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The Effect of Climate Change on Hydrological Regimes in Europe: A Continental Perspective
Abstract
This paper outlines the effects of climate change by the 2050s on hydrological regimes at the continental scale in Europe, at a spatial resolution of 0.5×0.5°. Hydrological regimes are simulated using a macro-scale hydrological model, operating at a daily time step, and four climate change scenarios are used. There are differences between the four scenarios, but each indicates a general reduction in annual runoff in southern Europe (south of around 50°N), and an increase in the north. In maritime areas there is little difference in the timing of flows, but the range through the year tends to increase with lower flows during summer. The most significant changes in flow regime, however, occur where snowfall becomes less important due to higher temperatures, and therefore both winter runoff increases and spring flow decreases: these changes occur across a large part of eastern Europe. In western maritime Europe low flows reduce, but further east minimum flows will increase as flows during the present low flow season – winter – rise. “Drought” was indexed as the maximum total deficit volume below the flow exceeded 95% of the time: this was found to increase in intensity across most of western Europe, but decrease in the east and north. The study attempted to quantify several sources of uncertainty, and showed that the effects of model uncertainty on the estimated change in runoff were generally small compared to the differences between scenarios and the assumed change in global temperature by 2050.
... Establishing a multi-model set by considering multiple simulations through a series of global climate models (GCMs) has become a common approach for understanding climate disorders [21,22]. Arnell (1999) determined that climate change significantly impacts flood risk [23]. Previous studies have examined the flooding frequency over climate change using different projected climate scenarios [24,25]. ...
... Establishing a multi-model set by considering multiple simulations through a series of global climate models (GCMs) has become a common approach for understanding climate disorders [21,22]. Arnell (1999) determined that climate change significantly impacts flood risk [23]. Previous studies have examined the flooding frequency over climate change using different projected climate scenarios [24,25]. ...
This study summarizes reviews on climate change’s impact on the water environment and hydrological regime. The results indicate a strong relationship between the climatological parameters and hydrological patterns. This relationship can be determined in two steps: (1) define the variations in climatological factors, particularly temperature and precipitation, and (2) measure the variations in runoff and inflows to streams and river systems using different statistical and global climate modeling approaches. It is evident that the increasing global temperatures have significant positive effects on runoff variations and evapotranspiration. Similarly, the increase in temperature has speeded up the melting of glaciers and ice on hilly terrains. This is causing frequent flash floods and a gradual rise in the sea level. These factors have altered the timing of stream flow into rivers. Furthermore, the accumulation of greenhouse gases, variations in precipitation and runoff, and sea-level rise have significantly affected freshwater quality. These effects are likely to continue if timely mitigation and adaptation measures are not adopted.
... The impact of climate change on the streamflow and therefore, the hydrological connectivity of basins has been an area of active research (e.g., Arnell 1999;Mimikou et al. 1999;Middelkoop et al. 2001;Chang et al. 2002;Smith et al. 2010Smith et al. , 2013. These studies indicate that there is a conclusive correlation between climate change and variability in stream flows. ...
... These studies indicate that there is a conclusive correlation between climate change and variability in stream flows. For example, Arnell (1999), Middelkoop et al. (2001), and Chang et al. (2002) predicted that the regional hydrology of the snow-dominated regions will observe significant variations under global warming scenarios and the month of maximum runoff are expected to shift. Since hydrological connectivity is expected to be conclusively impacted by climate change, this connectivity can effectively be used to evaluate the climate change-induced modifications to the material fluxes at the catchment scale (Smith et al. 2010). ...
Geomorphic connectivity among different
landscape compartments is a result of physical
linkage and material flux exchange. Physical
linkage is the structural component, and
material flux is the functional component of
connectivity. Both components are interlinked
and define catchments processes and
responses. Terrain characteristics such as
slope and topography control define structural
connectivity, whereas functional connectivity
is defined by processes and stimuli such as
rainfall events, land cover dynamics, and
tectonics. There exists feedback between
structural and functional connectivity, and
they actively modify each other to keep the
geomorphic system in an equilibrium state.
Under the climate change scenario, dynamics
of the processes such as rainfall and land
cover are changing rapidly, which in turn
affects the catchment connectivity and linkages. The present study first introduces the
concept of geomorphic connectivity in a
comprehensive manner and then discusses
the impact of climate change on catchment structures and processes in a theoretical
framework.
... Additionally, Trnka et al. [15] point out an increase in drought frequency, duration and severity in Central Europe, which is a direct consequence of climate change. Arnell [16] indicates that the significant changes in the flow regime occur in broad parts of Eastern Europe. Stahl et al. [17] indicate positive trends of annual runoff in western and northern Europe and negative trends in southern and eastern Europe based on the ensemble mean. ...
... Simulation results show that the most significant shifts in hydrological regimes occur in the regions where snowfall becomes less important due to higher temperatures caused by climate change. As a result, a large part of Eastern Europe will see an increase in winter run-off and a spring flow decrease [16]. At the same time, Rottler et al. [27] show that run-off will increase in winter and spring, while discharge will decrease in summer and at the beginning of autumn. ...
This paper presents changes in the flow of 14 rivers located in the Warta River basin, recorded from 1951 to 2020. The Warta is the third-longest river in Poland. Unfortunately, the Warta River catchment area is one of the most water-scarce regions. It hosts about 150 hydropower plants with a capacity of up to 5 kW. The catchment areas of the 14 smaller rivers selected for the study differ in location, size, land cover structure and geological structure. The paper is the first study of this type with respect to both the number of analyzed catchments, the length of the sampling series and the number of analyzed flow characteristics in this part of Europe. The analysis of changes in the river flows was performed with reference to low minimum, mean and maximum monthly, seasonal and annual flows. Particular attention was paid to 1, 3, 7, 30 and 90-day low flows and durations of the flows between Q50 and Q90%. In addition, the duration of flows between Q50 and Q90% were analysed. Analysis of the direction and extent of particular flow types was performed by multitemporal analysis using the Mann–Kendall (MK) and Sen (S) tests. The analysis of multiannual flow sequences from the years 1951–2020 showed that the changes varied over the time periods and catchments. The most significant changes occurred in the low flows, while the least significant changes occurred in the high flows. From the point of view of the operation of the hydropower sector, these changes may be unfavourable and result in a reduction in the efficiency of run-of-river hydropower plants. It was established that local factors play a dominant role in the shaping of river flows in both positive and negative terms, for the efficiency of the hydropower plants.
... This implies that river discharges increase because of wetter climate. This corresponds well with the results reported for other European catchments (Arnell, 2002). Singh & Bengtsson (2004) and Adeoye et al., (2018) found out that in rainy or wetland areas, increment of precipitation is primarily due to runoff rather than evaporation, because the amount of evaporation is nearly constant due to the already saturated land surface condition. ...
... Higher peak flows would potentially cause more floods, which would have some effect on agriculture and near river; urban areas would experience higher flooding frequency and flood risk. Expansion of urban and paved areas will most likely respond in higher mean annual river discharges and flashier river regimes, because of the quick delivery of rainwater to the river (Arnell, 2002;Otieno et al., 2013 andAdeoye et al., 2018) and as the land use pattern change over time, the runoff increases. Therefore, there is need for preventive measures to be taken to reduce flood risk. ...
Climate change has direct influence on environment and human existence. Climate change has been a monster posing threat to the hydrological cycle, hence the flow discharge of rivers. Therefore, it is necessary to study its effects on the flow of rivers thereby producing measures to alleviating its effects. In this study, the effects of land cover and weather conditions between 1967 and 2017 on the flow discharge of River Ona were investigated by making use of the climatic data (rainfall and temperature). The statistical variations in temperature and rainfall data were assessed using Statistical Program for Social Science (SPSS) in order to depict the linear variation, regression and correlation of the prevailing climate of the area The results showed that year 1998 and 1999 have the lowest and highest rainfall values respectively. The land-use maps show there is gradual increment in area of lands that are built-up but gradual reduction in the vegetal area. The runoff of River Ona would increase because of wetter climate caused by high rainfall in 1999. In addition, over the years, runoff severity tends to increase because of land development, giving rise to the replacement of vegetal areas by built up areas, which have low retention capacity in the area. The findings from this study can be used to predict the discharge of river given other weather and environmental factors.
... Although it is widely expected that the climate of the earth system will be systematically altered over the next century, the anticipated magnitude and nature of these changes vary widely depending on geographic location and modeling approach. Most model predictions of global climate change, however, predict regional increases in ambient temperature (IPCC, 2007), shifts in precipitation and storm frequency (e.g., Mulholland et al., 1998;Arnell, 1999;Rabalais et al., 2009), and increased acidity of the ocean (e.g., Hoegh-Guldberg et al., 2007). Recent model simulations in several large estuarine basins (e.g., Ni et al., 2019, Meier et al., 2011, Laurent et al., 2018 are consistent in their prediction of elevated respiration rates that drive elevated oxygen depletion. ...
... But because of a sharp decline in average rainfall, there has been a protracted drought. As a result, the Salento peninsula's climate can be characterized as virtually semi-arid (very high temperatures and insufficient precipitation): the dryness tends to occur in summer, while the precipitation is concentrated in autumn and winter, with only very few occurrences at the end of summer [17]. ...
Air pollution is a great threat to the sustainable development of the world; therefore, the improvement of air quality through the identification and apportionment of emission sources is a significant tool to reach sustainability. Single particle analysis, by means of a scanning electron microscope equipped with X-ray energy dispersive analysis (SEM-EDS), was used to identify the morphological and chemical properties of the PM10 particles in order to identify and quantify the main emission sources in three areas of Lecce, a city in the Apulia region of southern Italy. This type of characterization has not yet been performed for the Lecce site, but it is of particular importance to identify, based on the shape of the particles, the natural sources from the anthropogenic sources that are responsible for the serious health effects of the inhabitants. Three primary schools located in peripheral areas of the city were chosen for the sampling: “School 1” (A site), “School 2” (B site), and “School 3” (C site) to carry out a study of the air quality. The A site is characterized by a greater presence of calcium sulphates probably due both to construction activities present during sampling and to reactions between Ca particles and the sulfur present in the atmosphere. At the C site, there is a relative numerical abundance of different groups of particles that present, in the EDS spectrum, an enrichment in sulfur. At the B site, the number of particle groups is intermediate compared to that of the other two sites. With the source apportionment technique, ten emission sources were identified: combustion, soot, industry, soil, carbonates, sea salt, calcium sulfates, SIA, biological particles, and others. In PM10, the three sites are more affected by the soil source, with an effect greater than 60%.
... Musolin, 2007). Observations to date suggest that snow is becoming rarer in many regions of central and southern Europe (Arnell, 1999;Räisänen et al., 2004). Such climatic changes can have a fatal impact on a variety of organisms, including oligostenotermous winter-active insects. ...
This paper attempts to fill the gaps in knowledge about the biodiversity of some winter-active fly families from snowfields and caves in Vârghiș, Romania. A total of 15 fly species were recorded from caves and 9 species from snowfields. Exechiopsis (Exechiopsis) pseudindecisa Lastovka & Matile, 1974 and Rymosia placida Winnertz, 1863 from caves and Mycetophila mitis (Johannsen, 1912) (all Mycetophilidae) from snow represent the first records for Romania. Habitus photographs of these three species are provided.
... Lately, Papakostas et al. [103], conducted for Greece (Athens and Thessaloniki), confirmed the reduced demand for heat energy and the increase in energy consumption for cooling, due to the increase in air temperature. The results of earlier research also warned of the impact of climate change on reducing water availability and increasing water use [104][105][106][107]. Lehner et al. [108] pointed to the reduction of water resources in Eastern Europe due to two main causes: trends towards a dry climate and increasing water consumption for human use. ...
The aim of our paper is economic vulnerability assessment in the water sector of Montenegro, with a focus on electricity production in hydropower plants. The absence of an officially defined methodology in Montenegro, as well as in the region of South-East Europe represents a kind of challenge for research of this type especially for the assessment of economic damage caused by climate change and in the future period. In our paper, we treated negative impacts in the water sector as additional costs for the import of electricity due to reduced electricity production caused by the reduction of water potential due to climate change. After collecting, processing and analyzing data on electricity production in Montenegro, we prepared a projection of this production in the future period for the basic scenario - “without climate change”. This was followed by an assessment of the quantitative damage, in accordance with the determined climate scenarios. After analyzing electricity prices in the European market, we defined future unit were defined as a basis for damage assessment. We conclude the paper with the calculation and projection of economic damages caused by climate change in the Montenegrin energy sector. The basic variant of the analysis would be the existing price of electricity imports for 2022, in the amount of 200 EUR per MWh. The other two variants would be one higher and one lower electricity import prices (250 and 150 EUR per MWh, respectively), in order to gain an overview of the future price fluctuations in a certain way.
... One of the effects of urbanization in such areas is increasing the percentage of impervious surfaces which in itself causes environmental problems, and such a trend is common in urban cities. Moreover, studies show that global warming causes an increasing in extreme rainfall events (Arnell, 1999;Bates et al., 2008) and one of the solutions to cope with such problems is the adopting of new storm-water management strategies such as Low Impact Development policies (Voyde et al., 2010), Sustainable Urban Drainage Systems (SUDS) (Stovin, 2010), Low Impact Urban Design and Development policies (LIUDD) (Van Roon, 2005) and Water Sensitive Urban Design strategies (WSUD) (Beecham and Chowdhury, 2012)., The utilization of Green infrastructure through WSUD is among the possible solutions to reduce the negative impacts of urbanization particularly. ...
The application of green roofs is increasingly recognized in many countries as a solution to improve environmental quality and reduce runoff quantity. This study investigates the viability of super absorbing materials in a substrate mix for extensive green roofs, where plants are supported by lightweight growing media (substrate) overlying a drainage layer. In addition, the role of super absorbing materials as a growth medium, drainage properties of the substrate mix containing recycled materials, as well as its susceptibility to erosion and resistance to sliding when placed on a slope were investigated. Therefore, the main aim of this study is to investigate the impact of natural zeolite on rainfall infiltration into the soil, runoff, and soil water storage capacity in green roofs .This study includes the establishment, development, and performance of both grass and sedum model green roofs under simulated rainfall events. It indicates supportive suitability of the substrate mix containing recycled waste materials for plants growth. It is resistant to erosion and slippage and capable of providing good drainage. The results showed that infiltration in zeolite-treated soil is very high and treated soil can reduce drained water volume. In the treatment analysis, the highest rate of drained water was recorded as 20.5 (ml) and it was shown that in untreated soil there is a lacks of water as runoff, thus drainage and preserving water in the soils were too low and the lowest rate of drained water was seen in soil treated with 3% zeolite (5 ml).The results of this laboratory investigation were used to extend green roofs into the wider perspective of sustainability benefits.
... Precipitation is one of the most crucial parameters of the hydrological cycle. Climate change is intensifying the hydrological cycle, which is anticipated to have a major impact on regional water resources (Arnell 1999;River et al. 2018). Analyzing precipitation is important for several applications, such as hydrological and climate change impact studies (Azmat et al. 2018a). ...
Reliable spatial and temporal meteorological estimates are essential for accurately modeling hydrological, ecological, and climatic processes. High-resolution gridded datasets can be utilized for such applications, particularly in data-sparse regions. However, the validation of the accuracy of these products is necessary before their application in hydrological modeling for the assessment and management of water resources. In this study, high-resolution (0.08° × 0.08°), long-term station-based gridded datasets for precipitation and maximum and minimum temperatures were developed for the Potohar Plateau. Linear regression analysis was performed against the datasets and nearby stations for gap-filling during the base period. The observed gap-filled data were spatially interpolated using the ordinary kriging technique to obtain an observed gridded dataset. Five datasets for precipitation and three datasets for temperature were selected for evaluation in this study. GPCC, APHRODITE, ERA5-Land, MSWEP, and PERSIANN-CDR for precipitation, and CPC, CRU, and ERA5 for temperature were selected. The performance evaluation was performed using widely used statistical parameters (KGE, R², MAE, and RMSE). Bias correction was performed by selecting the best technique between linear scaling and quantile mapping. The results revealed that GPCC and ERA5 were the best-performing datasets for precipitation and temperature, respectively, among the evaluated datasets. For GPCC, KGE, R², MAE, and RMSE values were 0.75, 0.79, 21.22 mm, and 35.11 mm correspondingly, whereas, for ERA5, the aforementioned values were 0.87, 0.97, 1.5 mm, and 1.85 mm, and 0.92, 0.98, 1.05 mm, and 1.25 mm, respectively, for maximum and minimum temperature. Furthermore, linear scaling performed better than quantile mapping in bias correction. Finally, the GPCC and ERA5 datasets were bias-corrected to develop the final gridded dataset products for precipitation and temperature. This dataset will be utilized in hydro-climatological studies, which would be helpful in policy-making for sustainable water resources management.
... Climatic change can affect hydrological regimes in surface waters (Arnell, 1999;Shogren et al., 2020;Li et al., 2022). The significantly negative effect of discharge, Q, on indicator concentrations for many sites and years (Figs. 5 & 6) suggests the significant role of flow variability, that is, dilution under high flow conditions and increased concentration when flow is low. ...
Acid rain has degraded the environmental health of many regions worldwide since the Industrial Revolution. Signatures of river chemistry recovery from acid rain since the Clean Air Act and similar legislation have been reported extensively in small streams but are often subdued or masked in large rivers by complex, co-occurring drivers. Here we assess the recovery of river chemistry from acid rain deposition in the Mississippi River Basin (MRB), the largest river basin in North America. We combine analysis of temporal trends of acid rain indicator solutes with Bayesian statistical models to assess the large-scale recovery from acid rain and characterize effects of anthropogenic activities. We found evidence of river chemistry recovery from acid rain; however, the effects of other anthropogenic activities, including fertilizer application and road salting, and changing climate, are likely intensifying. Trends of pH, alkalinity and SO4 export suggest acid rain recovery at large in the MRB, with stronger evidence of recovery in the historically afflicted eastern region of the basin. The concentrations of acid rain indicators generally correlate positively to NO3 and Cl, indicating that N-fertilizer application may have significantly increased weathering, and possibly acidification, and road salt application likely increased cation loss from catchments and contributed to SO4 export. Temperature correlates positively with solute concentrations, possibly through respiration-driven weathering or evaporation. The concentrations of acid rain indicators correlate negatively and most strongly to discharge, indicating discharge as a predominant driver and that lower discharge during droughts can elevate concentrations of riverine solutes in a changing climate. Using long-term data, this study represents a rare, comprehensive assessment of the recovery from acid rain in a large river basin, taking into consideration the entangled effects of multiple human activities and climate change. Our results highlight the ever-present need for adaptive environmental management in a constantly changing world.
... The hydrological impact of a globally rising temperature is of large spatial variance, and there is a high probability that this will lead to higher river discharge in higher latitudes and lower discharge in the lower latitudes (Nijssen et al. 2001;Hirabayashi et al. 2013); however, findings indicate that total river runoff will probably increase (Labat et al. 2004). At the same time, the temporal variance of river runoff increases, leading to higher flood water levels and lower drought water levels (Arnell 1999). In that context, river training measures, such as groynes, are intended to limit the effect of seasonal variations of discharge and water level, with the overall aim of ensuring reliable navigation conditions (Alauddin and Tsujimoto 2012;Remo et al. 2009;Han et al. 2017). ...
River training structures, such as groynes or spur-dikes, are subject to intensifying ship-induced loads, owing to increasing ship dimensions and traffic density on waterways. In particular, the long-period primary wave system differs from other loading components, such as short-period wind waves, owing to the long wave length. To date, this loading scenario is not reflected within the empirical based design approaches for groynes. In this study, numerical approaches based on shallow water theory and computational fluid dynamics (CFD) are employed for deriving groyne design parameters, particularly by assuming stationary load conditions. Firstly, the numerical tools REEF3D::CFD and REEF3D::SFLOW are validated for the specific parameter range of ship-induced groyne overtopping based on an experimental data set. Secondly, numerical simulations at the prototype scale are connected with empirical equations for armor layer design. Comparing the results with field data from groyne prototypes indicates that the combined approach yields plausible required armor layer dimensions. Further, the examination of geometric variations of groynes confirms that a reduction in groyne slope can reduce the required armor layer dimensions by approximately 10%.
... The rainfall and temperature data for CC SWAT simulation were then prepared by applying this delta (projected change in temperature and precipitation) to the base precipitation and temperature data of 1998-2007. The abovementioned method, usually referred to as the delta method, is widely used in regional and local CC studies [9,[55][56][57] and is considered an efficient way to assess climate change with multiple GCM outputs [55]. Table 3 shows the selected CC models, corresponding climatic conditions, and average projected change in temperature and precipitation over the Brahmaputra basin. ...
Climate change (CC) is impacting the hydrology in the basins of the Himalayan region. Thus, this could have significant implications for people who rely on basin water for their lives and livelihoods. However, there are very few studies on the Himalayan river basins. This study aims to fill this gap by presenting a water balance for the Brahmaputra River Basin using the Soil and Water Assessment Tool (SWAT). Results show that snowmelt contributed about 6% of the total annual flow of the whole Brahmaputra, 21% of the upper Brahmaputra, and 5% of the middle Brahmaputra. The basin-wide average annual water yield (AWY) is projected to increase by 8%, with the maximum percentage increase in the pre-monsoon season. The annual snowmelt is projected to decrease by 17%, with a marked decrease during the monsoon but an increase in other seasons and the greatest percentage reduction in the upper Brahmaputra (22%). The contribution of snowmelt to AWY is projected to decrease while rain runoff will increase across the entire Brahmaputra and also in the upper and middle Brahmaputra. The impact assessment suggests that the upper Brahmaputra will be most affected by CC, followed by the middle Brahmaputra. The results can be used to support future water management planning in the basin taking into account the potential impact of CC.
... The rainfall and temperature data for CC SWAT simulation were then prepared by applying this delta (projected change in temperature and precipitation) to the base precipitation and temperature data of 1998-2007. The abovementioned method, usually referred to as the delta method, is widely used in regional and local CC studies [9,[55][56][57] and is considered an efficient way to assess climate change with multiple GCM outputs [55]. Table 3 shows the selected CC models, corresponding climatic conditions, and average projected change in temperature and precipitation over the Brahmaputra basin. ...
Climate change (CC) is impacting the hydrology in the basins of the Himalayan region. Thus, this could have significant implications for people who rely on basin water for their lives and livelihoods. However, there are very few studies on the Himalayan river basins. This study aims to fill this gap by presenting a water balance for the Brahmaputra River Basin using the Soil and Water Assessment Tool (SWAT). Results show that snowmelt contributed about 6% of the total annual flow of the whole Brahmaputra, 21% of the upper Brahmaputra, and 5% of the middle Brahmaputra. The basin-wide average annual water yield (AWY) is projected to increase by 8%, with the maximum percentage increase in the pre-monsoon season. The annual snowmelt is projected to decrease by 17%, with a marked decrease during the monsoon but an increase in other seasons and the greatest percentage reduction in the upper Brahmaputra (22%). The contribution of snowmelt to AWY is projected to decrease while rain runoff will increase across the entire Brahmaputra and also in the upper and middle Brahmaputra. The impact assessment suggests that the upper Brahmaputra will be most affected by CC, followed by the middle Brahmaputra. The results can be used to support future water management planning in the basin taking into account the potential impact of CC.
... The increasing risk of conflict as a result of the decrease in available water makes it necessary to make legal arrangements in this regard. For this reason, in the last 50 years, many studies have been carried out by international institutions, international legal associations, non-governmental organizations, and academics in the international arena (Arnell, 1999a(Arnell, , 1999b(Arnell, , 2003van Vliet et al., 2013;Sherwood and Fu, 2014;Rodell et al., 2018;UN-Water, 2018;Vano et al., 2010;Tramblay et al., 2020;Lehner et al., 2006;Smiatek et al., 2014;Amin et al., 2017). In this study, the important impacts of climate change on Turkish basins were investigated and the measures to be Review Article How to cite: Tokuslu, A. (2022). ...
Climate change, which is caused by the greenhouse gases released into the atmosphere by humans, disrupting the temperature, rainfall, and humidity balance on the earth, makes itself felt more and more every day. The effects of climate change are seen in oceans, habitats, briefly all over the world, from the equator to the poles. With the impacts of these effects, the polar glaciers are melting, the seawater level rises and soil losses increase in the coastal areas, while the severity and number of hurricanes, and floods increase in some parts of the world, while long-term droughts and desertification have started in some other regions. Climate change also affects water resources greatly, and it occurs as a decrease in water resources, forest fires, and related ecological deterioration. As a result of the decrease in the water flow in the river basins, water shortage started in the cities, agricultural production decreased and caused the expansion of arid or semi-arid areas. In this study, the impacts of climate change on Turkish basins were investigated and the measures to be taken were examined. Possible problems to be encountered in the future were mentioned and suggestions were made about what to do in the basins.
... Global warming effects upon water ecosystems have now been evident for years. The impact of climate change on freshwater availability was assessed both at regional (Arnell, 1999;Lehner et al., 2006), and global scale (Doll and Zhang, 2010;Sperna et al., 2012;Vorosmarty et al., 2000). Among others, several studies were carried out that highlighted significant warming in the European Alps, decreasing of snow and ice cover, and stream flows modification thereby (Bocchiola and Diolaiuti, 2010;Bocchiola, 2014;Fuso et al., 2020). ...
Habitat quality of alpine river is largely affected by human activity. The exploitation for hydropower, combined with anthropogenic climate change, can alter mountain riverine ecosystems, leading to less suitable hydro-thermal regimes for the fish. Here, we present a new methodology to assess water temperature within a river featuring water exploitation for hydropower purposes, usable to assess future potential deterioration of riverine habit suitability in response to (increasing) water temperature. We then propose an application focusing upon the case study of the Serio River, in Northern Italy, largely exploited by hydropower productions and highly populated by a very sensitive species, brown trout (Salmo trutta). The methodology proposed involves a set of tools, i.e. i) the hydrological model Poli-Hydro, to evaluate natural hydrological regime, ii) a hydropower plants scheme to assess river water withdrawal, iii) fish density-environment curves to evaluate the hydraulic suitability in terms of trout potential density for adult, young, and fry as a function of hydraulic features, i.e. depth and velocity, and iv) a new, physically based model, Poli-Wat.Temp, to assess changes in river water temperature, and possible outbreaks of temperature dependant lethal conditions, such as proliferative kidney disease, and others. To provide an assessment of river suitability, possibly complementing (improving?) models based upon solely hydraulic indexes, we propose a new synthetic River Stress index, combining i) potential fish density as driven by hydraulic variables, and ii) thermal suitability. Given that utmost unsuitable conditions (thermally, and likely hydrologically) are expected under future climate conditions pending global warming, we then projected water temperature, and stream flows until the end of the century, in response to socio-economic scenarios of AR6 of the IPCC, to explore the potential for future decrease of river quality. Water temperature would be largely susceptible to climate change with increase up to +6.5 C° in the worst scenarios, while no clear trend is observed for fish density. Overall, potential density would decrease in winter for adults, and in summer for juvenile and fry in downstream sections. Therefore, by coupling hydraulic, and thermal suitability, one finds that i) Alpine rivers would likely face longer critical periods, with respect to those predicted based upon a solely hydraulic habitat based assessment, and ii) continuous temperature increase as projected until the end of the century would result into worse conditions in summer months, seriously endangering fish guilds.
... Projections of water futures are fundamental for developing water resources management strategies under a changing climate. The projections are often developed using hydrological models run with future climate forcing informed by global circulation models (GCMs) or regional climate models (RCMs) (e.g., Arnell 1999a;Arnell 1999b;Graham et al. 2007;Chiew et al. 2009;. There is considerable uncertainty in the projections because of the compounding uncertainties in global emission and warming scenarios, future climate in particular rainfall projections, translating GCM or RCM outputs to catchment scale climate forcing, and hydrological modelling (Cisneros et al. 2014;Ekstrom et al. 2016;Chiew et al 2017). ...
Dominant hydrological processes of a catchment could shift due to a changing climate. This climate induced hydrological non-stationarity could affect the reliability of future runoff projection developed using a hydrological model calibrated for the historical period as the model or parameters may no longer be suitable under a different future hydroclimate. This paper explores whether competing parameterization approaches proposed to account for hydrological non-stationarity could improve the robustness of future runoff projection compared to the traditional approach where the model is calibrated targeting overall model performance over the entire historical period. The modelling experiments are carried out using climate and streamflow datasets from south-eastern Australia which has experienced a long drought and exhibited noticeable hydrological non-stationarity. The results show that robust multi-criteria calibration based on the Pareto front can provide a more consistent model performance over contrasting hydroclimate conditions but at a slight expense of increased bias over the entire historical period compared to the traditional approach. However, the robust calibration does not necessarily result in a more reliable projection of future runoff. This is because the systematic bias in any parameterisation approach would propagate from the historical period to the future period and would largely be cancelled out when estimating the relative runoff change. Ensemble simulations combining results from different parameterization considerations could produce a more inclusive range of future runoff projection as it covers the uncertainties due to model parameterization.
... The study of climate change impacts on different environmental systems has motivated many works, especially on water-related systems (Arnell, 1999;Middelkoop et al., 2001). Soil moisture (SM) is a key variable involved in many climatic, geophysical and biological processes, so monitoring its dynamics and understanding its (causal) relations in these processes are crucial. ...
Soil moisture (SM) plays a key role in the water cycle, and its variability is intimately linked to coupled land-atmosphere processes. Having a good knowledge of soil-atmospheric interactions is thus essential to assess the impact of climate change on SM; however, many aspects of how water and energy exchanges occur in the soil-atmosphere continuum are still uncertain. In particular, it is known that atmospheric circulation patterns influence climate conditions over Europe but their impact on SM has only rarely been studied. This study provides insight into how atmospheric patterns influence soil moisture dynamics in Europe, where an increase in temperature and agricultural droughts are expected as an impact of climate change. To do so, we analysed the influence of the North Atlantic Oscillation (NAO), the Arctic Oscillation (AO), and the El Niño Southern Oscillation (ENSO) on European SM, including lagged responses, for the period 1991–2020 at a monthly scale. Two methods have been used: a lagged correlation analysis and a more sophisticated causality approach using the PCMCI (PC method combined with the momentary conditional independence (MCI) test). SM series from two different databases were considered: the hydrological model LISFLOOD and the reanalysis dataset ERA5-Land. The results from the correlation analysis showed a significant, predominantly negative relationships of SM with NAO and AO over almost all of Europe and no significant relation with ENSO. With the causality analysis, similar patterns are obtained for NAO and AO; however, the PCMCI analysis revealed clear patterns of ENSO influencing SM with a delayed response of one-to-two months in central and northwest Europe. The results obtained in this work highlight that there are causal relations between the main modes of interannual climate oscillations and SM variations in Europe, underlining the importance of accounting for global atmospheric circulations to study current changes in regional soil water-related processes.
... The study of climate change impacts on different environmental systems has motivated many works, especially on water-related systems (Arnell, 1999;Middelkoop et al., 2001). Soil moisture (SM) is a key variable involved in many climatic, geophysical and biological processes, so monitoring its dynamics and understanding its (causal) relations in these processes are crucial. ...
... The main question addressed is whether the impact of warming on mountain snow and annual runoff can be offset by precipitation increases. This has not been resolved in the literature (e.g., Arnell, 1999;Prowse et al., 2006;Luo et al., 2008). The specific objective for this sensitivity analysis is, therefore, to quantify the response of simulated mountain hydrological processes to changes in air temperature and precipitation associated with future climate change. ...
Whether or not the impact of warming on mountain snow and runoff can be offset by precipitation increases has not been well examined, but it is crucially important for future downstream water supply. Using the physically based Cold Regions Hydrological Modelling Platform (CRHM), elasticity (percent change in runoff divided by change in a climate forcing) and the sensitivity of snow regimes to perturbations were investigated in three well-instrumented mountain research basins spanning the northern North American Cordillera. Hourly meteorological observations were perturbed using air temperature and precipitation changes and were then used to force hydrological models for each basin. In all three basins, lower temperature sensitivities of annual runoff volume (≤ 6% °C⁻¹) and higher sensitivities of peak snowpack (-17% °C⁻¹) showed that annual runoff was far less sensitive to temperature than the snow regime. Higher and lower precipitation elasticities of annual runoff (1.5 – 2.1) and peak snowpack (0.7 – 1.1) indicated that the runoff change is primarily attributed to precipitation change and, secondarily, to warming. A low discrepancy between observed and simulated precipitation elasticities showed that the model results are reliable, and one can conduct sensitivity analysis. The air temperature elasticities, however, must be interpreted with care as the projected warmings range beyond the observed temperatures and, hence, it is not possible to test their reliability. Simulations using multiple elevations showed that the timing of peak snowpack was most sensitive to temperature. For the range of warming expected from North American climate model simulations, the impacts of warming on annual runoff, but not on peak snowpack, can be offset by the size of precipitation increases projected for the near-future period 2041-2070. To offset the impact of 2°C warming on annual runoff, precipitation would need to increase by less than 5% in all three basins. To offset the impact of 2°C warming on peak snowpack, however, precipitation would need to increase by 12% in Wolf Creek in Yukon Territory, 18% in Marmot Creek in the Canadian Rockies, and an amount greater than the maximum projected at Reynolds Mountain in Idaho. The role of increased precipitation as a compensator for the impact of warming on snowpack is more effective at the highest elevations and higher latitudes. Increased precipitation leads to resilient and strongly coupled snow and runoff regimes, contrasting sharply with the sensitive and weakly coupled regimes at low elevations and in temperate climate zones.
... Today, many important cities worldwide have paid more attention to the concept of sustainable development to reduce the negative effects of their city development on the quality and quantity of runoff by using modern management technologies, including Best Management Practices (BMP) and Low Impact Development (LID). These methods promote a better balance among natural resource conservation, growth and development, ecosystem protection, public health, and quality of life [4][5][6][7][8]. One of the methods to control the rain on the spot and reuse it is called the green roof method. ...
One of the methods to control the rain on the spot and reuse it is the green roof. This method uses a multi-layer system of vegetation on the roof and balcony of a building to absorb part of the rainwater; the volume and peak runoff are also reduced by evaporation, transpiration, and treatment processes. This research was conducted as a field experiment in the hydraulic laboratory of the Agriculture Faculty in the University of Zanjan, Iran. The factors of the study design included a green roof covered with shards of brick and cultivated soil (grass). The experiments were performed at rainfall intensities of 45, 55, and 65 mm/h with 5, 10, and 25 year return periods, respectively. Also, the volume of the water stored and drainage was measured in different conditions. The results of this study showed that regardless of the type of materials used in the green roof, with increasing time, the amount of water stored in the green roof decreased, and the amount of drained water increased. A comparison of the average performance of the brick and grass modifiers for green roofs showed that the volume of the stored water in the grass corrector was higher; if the shards of bricks were used, 69% of the rainfall would be stored, and 31% was drained. However, adding grass to the green roof increased the volume of stored water to 78% and reduced the volume of drainage water to 22%. Also, the presence of grass on the green roof reduced the electrical conductivity by 32% compared to the single brick.
... Extreme weather events cause serious alterations in the hydrological regime at various spatial scales, involving both surface waterbodies (Woodward et al., 2016) and groundwater aquifers (Cuthbert et al., 2019;Taylor et al., 2013), with a drastic decrease in the discharge of watercourses in periods of drought alternating with periods of intense rainfall and flash-flood events (Beniston et al., 2007;Di Baldassarre et al., 2017). Non-perennial rivers and streams now represent more than 50% of the global river network Skoulikidis et al., 2017), but these numbers are predicted to drastically increase in some climatic and geographic regions (Acuña et al., 2014;Arnell, 1999;Döll & Schmied, 2012). For example, in the coming decades, a decrease in the discharge of rivers and streams in the European-Mediterranean region is expected (Milly et al., 2005;Skoulikidis et al., 2017); some river basins already subject to reduced levels of available superficial flow may present a further reduction of 10% by 2030, with a significant increase in the intermittence phenomena and complete drought of former perennial rivers (IPCC, 2018). ...
Because of global change and increasing anthropogenic pressures, non‐perennial rivers and streams are predicted to drastically increase in the European‐Mediterranean region. Some river basins already subject to reduced levels of available superficial flow, may present a further reduction, with a significant increase in intermittence phenomena and complete drought of former perennial rivers. In this context, a sound knowledge of the ecological effects of increasing drying events on these watercourses may help to better predict impacts of the altered flow regime on structure and functions of freshwater ecosystems. In this paper we assessed the long‐term response of invertebrate assemblages and ecosystems processes to antecedent drying events (drying memory) in a Central Apennine river (Italy). We demonstrated that compared to the perennial reach, the 7‐Km downstream intermittent site, after more than one year from a complete superficial flow resumption, still conserved the “memory” of past disturbance with marked differences in structure, composition and functional traits of assemblages which, in turn, negatively influenced the leaf‐litter breakdown process. Despite total abundance and taxa richness were on average higher at the intermittent site, antecedent droughts determined a decline of shredders and scrapers and an increase of collectors. In addition, some more sensible, semivoltine and rheophile taxa were replaced by generalist, multivoltine and more resistant taxa. Our findings confirm and extend the “drying memory” hypothesis and suggest that irregular drying events in former perennial Apennine rivers may have dramatic long‐term effects on both structure and functions of lotic ecosystems.
... The degradation of the equilibrium of the environment caused by human activity and the consumption of natural resources for energy production and general inputs is a matter of global concern and growing importance (Letcher 2019;Qiao et al. 2019). The increase of the greenhouse gases (GHGs) concentration in the atmosphere straightly affects climatic parameters (planet global temperature, changes in rainfall patterns, extreme weather events, among others) (Arnell 1999;Jacob and Winner 2009;Kumar et al. 2018). Consequently, researchers and the scientific community stay alert looking for new and optimal strategies to control emissions from different productive activities. ...
Palladium was incorporated into carboxymethylated cellulose fibers as a support, thereby becoming an efficient and stable catalyst for low temperature gas phase reaction. Thus, NO was used as test molecule of Greenhouse Gas to be catalytically reduced with hydrogen on an eco-friendly sustainable material containing palladium as the active site. Prior to the catalytic test, the catalysts were reduced with glucose as an eco-friendly reagent. The material characterization was performed by SEM–EDS, XRD, LRS, TGA and FTIR. The catalytic results showed that at 170 °C, NO conversion was 100% with a selectivity of 70% to nitrogen. While NOX species were completely converted into N2 at temperatures higher than 180 °C. The starting commercial dissolving pulp was also studied, but its performance resulted lower than the ones of functionalized fibers. The use of this strategy, i.e., the functionalization of cellulose fibers followed by in-situ formation of metallic nanoparticles, can be further applied for the design of a wide range of materials with interesting applications for gas and liquid phase reactions under mild conditions.
Graphic abstract
... ). Arnell (1999) explained that a temperature rise can lead to a general reduction in the proportion of precipitation falling as snow, and a consequent reduction in many areas in the duration of snow cover. Dey and Kumar (1983) found an inverse relationship (negative correlation) between Indian Summer Monsoon (ISM) rainfall and the extent of snow cover in the Himalayas, which suggests that there might be a link between increasing rainfall and decreasing snowfall in the Mustang region. ...
Climate change is a proven and burning issue in this world. It has visibly impacted different nations. From this research on Gharapjhong Rural Municipality of Mustang district of country Nepal, it is again proved that the climate at the local level has been experiencing increasing trends of both precipitation and temperature as per the data from 1988 to 2017. The study was conducted to study the impact of climate change on agriculture of the Mountainous area of Nepal i.e. Gharapjhong Rural Municipality of Mustang District. Field observation, Questionnaire survey, Key Informant Interview, and Focus Group Discussion was carried out to obtain primary data whereas; secondary data were collected from the Department of Hydrology and Meteorology, Ministry of Agriculture and Livestock Development, Budget program for Gharapjhong Rural Municipality (2074/2075), authorized report and papers. Different trend analyses and correlations were plotted to validate the research objectives. The analysis of productivity trend (1999/00-2016/17) was found to be increased in maize, potato, barley whereas decrement of trend in wheat and oilseed. Apple productivity data from the year 2012/13 to 2016/17 also shows linear increments. Both the agricultural data analysis part and local people's experience part show similar outcomes, i.e. positive as well as negative impact on agricultural production due to climate change. Analysis of sales of chemical fertilizers data (2013/14 to 2016/17) shows the increasing trend of chemical fertilizers. The majority of the respondents are practicing inter-cropping, planting new crops, increasing the use of biofertilizers and pesticides. Whereas, every respondent is using an irrigation system to cope with an increasing climatic trend.
... In recent years, many researchers are concerned about the temporal and spatial variability of precipitation rate. (Arnell 1999;Camici et al. 2014;Fennessy et al. 1994;Ficklin et al. 2009;Liu et al. 2015;Pachauri et al. 2014;Pandey et al. 2017;Sneyers 1997;Ting and Wang 1997;Tiwari and Pandey 2019). ...
... In the Cantabrian Mountains, a reduction of the regulatory effect of the accumulated snow in mountain areas is also detected, producing an earlier snowmelt of about 45 days and a much more accentuated low water level in rivers from April. These results agree with previous studies predicting that by the end of the twenty-first century, the peak flow of many North American and European rivers is expected to occur 30-40 days earlier as a result of earlier snowmelt [40,41], but changes in precipitation caused by climate change can increase or reduce flow rates. ...
Climate change undoubtedly will affect snow events as temperature and precipitation are expected to change in the future. Spanish mountains are especially affected by that situation, since snow storage is there focussed on very specific periods of the hydrological year and plays a very important role in the management of water resources. In this study, an analysis of the behaviour of the complex snow-related phenomena in the four main mountain regions of Spain in the next 50 years is conducted. The ASTER hydrological model is applied using temperature and precipitation data as basic input, estimated under a climate change scenario. Results show different changes in the maximum and average expected flows, depending on the very different magnitude and sign of changes in precipitation. An increase of flooding episodes may occur as a result of a complex relation between changes in precipitation and an increase in maximum snowmelt intensities that range from 2.1% in the Pyrenees to 7.4% in the Cantabrian Mountains. However, common patterns are shown in a shorter duration of the snow bulk reserves, expected to occur 45 days earlier for the Cantabrian Mountains, and about 30 days for the rest of the studied mountain regions. Changes observed also lead to a concerning decrease in the regulatory effect of the snow-related phenomena in the Spanish rivers, with a decrease in the average snow accumulation that ranges from about 28% for the Pyrenees and Sierra Nevada to 42% for the Central System and the Cantabrian Mountains. A decrease in average flow is expected, fluctuating from 2.4% in the Pyrenees to 7.3% in Cantabrian Mountains, only increasing in the Central System by 4.0%, making all necessary to develop new adaptation measures to climate change.
... Some regulations are based on identifying the month of the year with the lowest flow (e.g., LQ50 in Table 1). In a study of the impact of climate change on the flow regimes in Europe, Arnell [28] indicated that the most significant changes are expected in the eastern part of the continent, where the snow water equivalent (SWE) will likely decrease and shift in part to liquid precipitation due to higher temperatures. This change will lead to winter runoff increases and spring flow decreases, which may, in turn, exacerbate summer low flows. ...
Environmental flows (eflows) refer to the amount of water required to sustain aquatic ecosystems. In its formal definition, three flow characteristics need to be minimally maintained: quantity, timing and quality. This overview paper highlights the challenges of some of the current methods used for eflow determination in the context of an evolving climate. As hydrological methods remain popular, they are first analyzed by describing some of the potential caveats associated with their usage when flow time series are non-stationarity. The timing of low-flow events will likely change within a season but will also likely shift in seasonality in some regions. Flow quality is a multi-faceted concept. It is proposed that a first simple step to partly incorporate flow quality in future analyses is to include the water temperature as a covariate. Finally, holistic approaches are also critically revisited, and simple modifications to the Ecological Limits of Flow Alteration (ELOHA) framework are proposed.
... They highlight a link (R = 0.49) between runoff and rainfall changes. Finally, this will tend to preserve the MP groundwater quality as greater runoff results generally in greater loads of salts, fecal coliforms, pathogens and heavy metals (Arnell 1999) that can seep into the aquifer. ...
A multidisciplinary approach was carried out in Douala, a humid tropical coastal megacity (Cameroon, West Africa) which already experiences some environmental changes due to population growth, urbanization and industrialization. We aimed at identifying the hydrological processes involved in this peculiar site, which records approximately 4 m of rainfall/year and undergoes almost continuous rainfall during year. Moreover since it is well known that modifications in land uses may profoundly influence hydrology, we need to improve our understanding on key hydrological processes in such tropical humid. To answer this question, we focus on water fluxes across the critical zone (land–atmosphere-subsurface continuum) through isotopic and chemical data from water vapour, rainfall and groundwater.Concerning atmospheric fluxes, results highlight an influence of large scale meteorological conditions on precipitation stable isotope composition. Classical processes (thermo-dependency, amount effect, continental recycling) observed elsewhere cannot be applied in Douala region. The intensity of upstream convection and the size of convective system mostly impact monthly and daily rainfalls. We also put in evidence that extended clouds in altitude, due to strong convection, provoke depleted precipitation in heavy isotopes. Moreover, the isotopic signature in rainfall is similar to that of water vapour, thus meaning a lack of post-condensational effects.By coupling this isotopic signal of precipitation with that of groundwater, we show that the Mio-Pliocene aquifer in Douala is recharged locally by rainwater and that this recharge occurs preferentially from April to August and November. There is no fractionating process during the infiltration of rainwater. Stable isotopes in groundwater highlight the existence of different flow paths within this multi-layered aquifer. We identified a deep flow path that mays correspond to groundwater with long residence time compared to shallower ones. Information obtained by the isotopes is similar to that provided by hydro-meteorological and potentiometric data. The aquifer recharge varies between 892.6 mm and 933.6 mm/year. Rainwater infiltrates at high altitudes, then flows underground with a velocity estimated to 1.96 m/day, before reaching the estuary. Groundwater chemistry enforces these findings. Water mineralization clearly increases along a flow path conducting water from the recharge zone (high altitudes) to the discharge area (estuary). Concentrations in main ions are partly controlled by rainfall intensity through the dilution effect, water-rocks interactions processes and human activities.The impacts of these human activities on groundwater quantity and quality, but also, on a more general way on climatic changes within the region, have been then deeply investigated. The results show that there is a widespread degradation of groundwater quality due to anthropogenic activities, leading also to seawater intrusion in some coastal megacities of West Africa. Groundwater deterioration tends to be emphasized by climate change (through an increase in CO2, increase in air temperatures and slight increase in precipitation amount).Finally this thesis provides new insights for tropical hydrology and key management tools to Douala water resource managers.Keywords: Douala, Rainwater; Mio-Pliocene groundwater; stable isotopes; major ions; upstream convection; anthropogenic activities, critical zone.
... Many authors have devoted significant efforts to evaluate net water resources in climate change projections, on all scales from global to basin [3][4][5][6][7][8][9]. Their results show that climate change will affect, in varying ways and to different extents, each region of the planet. ...
Recent trends suggest that streamflow discharge is diminishing in many rivers of Southern Europe and that interannual variability is increasing. This threatens to aggravate water scarcity problems that periodically arise in this region, because both effects will deteriorate the performance of reservoirs, decreasing their reliable yield. Reservoir storage is the key infrastructure to overcome variability and to enhance water availability in semiarid climates. This paper presents an analysis of the role of reservoir storage in preserving water availability under climate change scenarios. The study is focused on 16 major Southern European basins. Potential water availability was calculated in these basins under current condition and for 35 different climatic projections for the period 2070–2100. The results show that the expected reduction of water availability is comparable to the decrease of the mean annual flow in basins with large storage capacity. For basins with small storage, the expected reduction of water availability is larger than the reduction of mean annual flow. Additionally, a sensitivity analysis was carried out by replicating the analysis assuming variable reservoir volumes from 25% to 175% of current storage. The results show that increasing storage capacity attenuates the reduction of water availability and reduces its uncertainty under climate change projections. This feature would allow water managers to develop suitable policies to mitigate the impacts of climate change, thus enhancing the resilience of the system.
... It has been projected that by the end of this century, the peak flow from the snowmelt in many American and European rivers would be 30-40 days earlier than the beginning of 2000s (Arnell, 1999). During 1974During -2003, the snowmelt floods in Canada showed a decreasing trend (Cunderlik and Ouarda, 2009). ...
The cryosphere is an important component of the global climate system. Cryospheric components are sensitive to climate warming, and changes in the cryosphere can lead to serious hazards to human society, while the comprehensive understanding of cryospheric hazards largely remains unknown. Here we summarized the hazards related to atmospheric, oceanic and land cryosphere. The different types of cryospheric hazards, including their phenomena, mechanisms and impacts were reviewed. Our results suggested that: 1) The recorded hazards from atmospheric cryosphere including frost, hail, freezing rain decreased or showed great spatial heterogeneities, while their future changes are difficult to predict, and the extreme cold events in winter may increase in the future; 2) Sea ice extent declines rapidly, and iceberg numbers will increase. The permafrost-dominated coastline erosion will be exacerbated by climate warming. Meanwhile, the sea level rise is expected to continue in the next decades; 3) The glacier collapse, glacial lake outbursts and paraglacial readjustments will increase in the future. Although the total area of snow cover will decrease, the heavy snow events, snow avalanches, and snowmelt floods will not decrease simultaneously. The permafrost-related rock and debris flow and thaw slump will also increase with permafrost degradation. Taken together, we concluded the cryosphere is shrinking, while cryospheric hazards will likely in a warming climate.
... Hydroclimate variability affects natural and human systems globally, and extreme events such as floods, droughts, and heatwaves can alter ecosystem functioning, disrupt food production and security 1,2 , significantly impact ecology and carbon sequestration 3,4 , affect water availability 5 , damage human settlements and increase mortality 6 . These extreme events are likely to be exacerbated by global warming 7,8 . ...
Central Europe has experienced a severe drought almost every April for the last 14 years consecutively, driven by record high temperatures, low flows, high evapotranspiration, and high soil moisture deficit. The dynamic of this recent and recurrent midspring
dryness is not yet understood. Here we show that the period 2007–2020 was characterized by a reduction of ~50% of the usual April rainfall amount over large areas in central Europe. The precipitation deficit and the record high temperatures were
triggered by a multiyear recurrent high-pressure system centered over the North Sea and northern Germany and a decline in the temperature gradient between the Arctic region and the mid-latitudes, which diverted the Atlantic storm tracks northward. From a
long-term perspective, the precipitation, temperature, and soil moisture anomalies observed over the last 14 years have reached the highest amplitudes over the observational record. Our study provides an in-depth analysis of the hydroclimate extremes in central Europe over the last 140 years and their atmospheric drivers, enabling us to increase our dynamical understating of longterm dry periods, which is vital to enhance forecasting and mitigation of such events.
... These aims were achieved by analyzing the responses of PET to perturbations in four of its driving climatic variables, namely temperature (T ), relative humidity (RH), solar radiation (R s ) and wind speed (u z ), at 30 study sites across Australia representing a range of climate zones. Both the Penman-Monteith and Priestley-Taylor models were used, as they represent different conceptualizations of the PET-related processes, with both models being widely used for climate impact assessments (Felix et al., 2013;Arnell, 1999;Gosling et al., 2011;Kay et al., 2009;Prudhomme and Williamson, 2013;Donohue et al., 2009). It is worth noting that the potential changes in one climate variable can be amplified or offset by changes in another variable (for examples see the discussions of "evaporation paradox" in Lu et al., 2016;Roderick and Farquhar, 2002), which can affect the relative importance of each variable. ...
Understanding the factors that impact on the sensitivity of potential evapotranspiration (PET) to changes in different climate variables is critical to assessing the possible implications of anthropogenic climate change on the catchment water balance. Using global sensitivity analysis, this study assessed the implications of baseline climate conditions on the sensitivity of PET to a large range of plausible changes in temperature (T), relative humidity (RH), solar radiation (Rs) and wind speed (uz). The analysis was conducted at 30 Australian locations representing different climatic zones, using the Penman–Monteith and Priestley–Taylor PET models. Results from both models suggest that the baseline climate can have a substantial impact on overall PET sensitivity. In particular, approximately 2-fold greater changes in PET were observed in cool-climate energy-limited locations compared to other locations in Australia, indicating the potential for elevated water loss as a result of increasing actual evapotranspiration (AET) in these locations. The two PET models consistently indicated temperature to be the most important variable for PET, but showed large differences in the relative importance of the remaining climate variables. In particular, for the Penman–Monteith model wind and relative humidity were the second-most important variable for dry and humid catchments, respectively, whereas for the Priestley–Taylor model solar radiation was the second-most important variable, particularly for warmer catchments. This information can be useful to inform the selection of suitable PET models to estimate future PET for different climate conditions, providing evidence on both the structural plausibility and input uncertainty for the alternative models.
... These studies also predicted for 2025 and above mentioned countries will growing to get affected by climate change and water resource stress. By the year 2050s and 2080s, other countries in southern Africa will derive into the stressed class and pressures will grow much rapidly in Africa and parts of southern Asia and Eastern Europe (Arnell 1999). Coastal aquifer is an important sources of freshwater and saltwater intrusion. ...
Groundwater is around one third of global water withdrawals and serve drinking water. Coast is a most sensorial and dynamic geomorphic unit where marine, Aeolian, and terrestrial system meet. Coast is a potential area for human dwell, around 70% of world population live along the coast, and this population is growing exponentially to support the increasing population growth and development requires a large quantity of freshwater. In several areas groundwater resource is a subject of worry in respect to both quantity and quality. Groundwater salinization is considered a specific category of pollution that portends groundwater resources, because mixing a small quantity of saltwater with groundwater makes freshwater unsuitable and can result in abandonment of freshwater supply. Pumping or over extraction is considered the key reason of saltwater intrusion into coastal groundwater aquifers in several areas of the world although climate change and global warming have significantly accelerated sea-level rise and groundwater recharge. Saltwater intrusion poses a major restriction to utilization of groundwater so saltwater intrusion should be prevented or at least have to be controlled. It is essential to practical measures and protect the available groundwater resources from pollution, saltwater intrusion, and contaminants which deplete quality. The modern computer modelling techniques can be used to design better groundwater withdrawal networks and methods to reduce the probability of sea-water intrusion and contaminations.
... Alcamo et al., 2007, examined the long-term changes in global water resources, driven by socioeconomic and climatic changes. [19] examined the effect of climate change on hydrological regimes in Europe. ...
Global spatial and annual distribution of surface water vapour density were estimated using 2005 -2016monthly air temperature and relative humidity at 1° ×1° resolution obtained from Era interim and NCEP/NCAR database products. Obtained results from reanalysis were statistically tested using in situ data from Tropospheric Data Acquisition Network (TRODAN) of The Center for Atmospheric Research (CAR). Four seasonal variations of surface water vapour density (winter (DJF), spring (MAM), summer (JJA) and autumn (SON)) was examined. Observed result from the two reanalysis follow similar trends with value from Era interim leading.High values ranges between 50 g/m2 and 68 g/m2 were observed in tropical regions and humid sub-tropical regions. Low values ranges between 8 g/m2 and 38 g/m2 were observed in Ice cap, Tundra and arid regions. High warming may be experienced in tropical and sub-tropical regions, similarly, climatechange with alarming
rate may be experienced in locations with low values. The annual cycle of surface water vapor density is clearly established from two reanalysis across world classified into twelve regions. The statistical test for the reanalysis present good result with a mean bias error, MBE, root mean square error, RMSE and R square of 20.56, 18.29, 0.87 and 5.87, 0.98, 0.93 for Era interim and NCEP/NCAR respectively.
Study Region: Mountains play a crucial role in supplying water for consumption, irrigation, and hydroelectric power. However, they are highly vulnerable to climate change. The Pyrenees exemplify a mountainous region undergoing significant changes, notably in land-use practisces, with a significant shift towards forest cover. Study Focus: We use the SWAT model, to analyse in depth two factors that most influence the hydrological cycle: land-use change and climate variability. The model is calibrated and validated using daily streamflow for the periods 1992-2004 and 2005-2018. The following results were obtained for both periods: an NSE of 0.51, an R2 of 0.72, and a PBIAS of-12.67 % for the calibration period and an NSE of 0.55, an R2 of 0.75, and a PBIAS of-16.49 % for the validation period, indicating that the model accurately represented the daily streamflow. Subsequently, we designed three scenarios based on combinations of historical data to quantify the contribution of each factor. New Hydrological Insights for the Region: Comparing the scenarios confirms the downward trend of streamflow in the region and provides quantitative information on the influence of each factor on this decline. Notably, that land-use changes account for 41.4 % almost as much as the climate variability. Furthermore, we observed an increase in the frequency and magnitude of floods with an increase in flood parameters of about 40%. The alteration of these parameters is slightly mitigated by reforestation, leading to a decrease of 5%.
شهرها و روستاها به عنوان اراضی که دارای سطوح وسیعی از اراضی غیرقابل نفوذ و یا کم نفوذ شامل کاربریهای مختلف
بوده که دارای توان استحصال قابل توجه نزولات جوی می باشد. طراحی شبکه های هدایت، جمع آوری و دفع آبهای
سطحی این مناطق می تواند با رویکرد جمع آوری آبهای سطحی ناشی از نزولات جوی به منظور کاهش اثرات کم آبی
بخصوص در مناطق خشك و نیمه خشك کشور صورت گیرد. از آنجا که سیستم جمع آوری آبهای سطحی هنوز به عنوان
مساله مهمی در طراحی ها در نظر گرفته نشده و مشکلات ناشی از آن به وضوح در سطح شهرها دیده می شود لذا
شایسته است که بر این معضل اهمیت خاصی داده شود. هدف ازاین مطالعه بررسی یکی از روش های جمع آوری رواناب
سطحی در نزدیکی منطقه تازه کند و سد نهند می باشد. نتایج نشان داد که با توجه به حجم بارش و میزان رواناب،
میتوان با روش های مدیریتی این حجم رواناب را به سد نهند منتقل و یا با استفاده از سازه های انتقال آب، جریان را به
سمت مناطق مسکونی برده و در مصارف غیر آشامیدنی از این منبع آبی استفاده کرد .
The promise of a healthier, more comfortable, and more productive way of life has fueled a rapid technological transition, and a regenerative built environment has emerged as the tagline to denote the recent sustainable development. In the built environment, the regenerative paradigm has emerged as a transformative approach that goes beyond mere sustainability, aiming to restore, renew, and enhance the ecosystems affected by human activities. However, the concept of the regenerative paradigm and its potential to foster sustainable development has been understudied in recent time. Therefore, this paper explores how we can transform the built environment in the face of the present impacts of climate change using a new regenerative paradigm concept. The objectives of the study are: (i) to explore the predictors of climate change, (ii) to determine the negative impacts of environmental issues on inhabitants’ health, and (iii) to explore adaptive climate change strategies for Nigeria’s regenerative built environment. The study sample consisted of 235 stratified respondents’ opinions from within the built environment in southwestern Nigeria collected via a self-administered questionnaire. The collected quantitative data was analysed using SPSS (version 22) logistic regression analysis. The major results of the analysis revealed: (i) the ten most important predictors of climate change indicators, (ii) the existence of negative consequences of the impacts of climate change on inhabitants’ health in southwestern regions of Nigeria, and (iii) a significant (p ≤ 0.05) in all regenerative factors: planting native species has the highest β coefficient of 0.499, followed by the biophilic approach (0.494), the establishment of a city’s tree canopy (0.467), the creation of a green functional green space (0.436), the use of smart landscaping techniques (0.388), and the development of a healthy watershed (0.314). This indicates that to have a regenerative built environment it is essential to create a functional green space, plant native species, establish a city’s tree canopy, create a healthy watershed, and render a biophilic approach. The study’s recommendations include urgent action to integrate climate change interventions into the decision-making processes, initiatives, and development plans of the Nigerian government. This integration should prioritize sustainable practices within the built environment, considering the regenerative paradigm’s potential to address climate change impact effectively.
Streamflow rate changes due to damming are hydro-ecologically sensitive in present and future times. Very less studies have done an investigation of the damming effect on the streamflow along with future forecasting, which can be the solution for the existing problems. Therefore, this study aims to use the Pettitt test as well as standard normal homogeneity test (SNHT) to discover trends in streamflow with the future situation in the Punarbhaba River in Indo-Bangladesh from 1978 to 2017. Trend was spotted using Mann–Kendall test, Spearman’s rank correlation approach, innovative trend analysis, and a linear regression model. The current work additionally uses advanced machine learning techniques like random forest (RF) to estimate flow regimes using historical time series data. 1992 appears to be a yard mark in this continuum of time series datasets, indicating a significant transformation in the streamflow regime. The MK test as well as Spearman’s rho was used to find a significant negative trend for the average (−0.57), maximum (−0.62), and minimum (−0.48) flow regimes. The consistency of the flow regime has been losing consistency, and the variability of flow regime has increased from 2.1 to 6.7% of the average water level, 1.5 to 6.5% of the maximum streamflow, and 3.1 to 5.8% of the minimum streamflow in the post-change point phase. The forecast trend using random forest for streamflow up to 2030 are negative for all four seasons with a flow volume likely to be reduced by 0.67% to−5.23%. Annual and monthly streamflows revealed very negative tendencies, according to the conclusions of unique trend analysis. Flow declination of this magnitude impacts downstream habitat and environment. According to future estimates, the seasonal flow will decrease. Furthermore, the outcome of this research will give a wealth of data for river management and other places with comparable environment.
Extreme climatic events present society with significant challenges in a rapidly warming world. Ordinary citizens, the insurance industry and governments are concerned about the apparent increase in the frequency of weather and climate events causing extreme, and in some instances, catastrophic, impacts. Climate Extremes and Society focuses on the recent and potential future consequences of weather and climate extremes for different socioeconomic sectors. The book also examines actions that may enable society to better respond to climate variability. It provides examples of the impact of climate and weather extremes on society. How have these extremes varied in the past, and how might they change in the future? What type of efforts will help society adapt to potential future changes in climate and weather extremes? The book is designed for all policy-makers, engineers and scientists who have an interest in the effects of climate extremes on society.
Europe has relatively uniform rainfall distribution and less water-related disasters when compared with other continents. Even so, desalination plants have been constructed in many places like Greece, London, and Barcelona. In the future, due to climate change and population growth, it is possible that more and more cities may have the water-shortage problem. This chapter investigates the possible coastal reservoirs for capital cities in Europe. It is found that Greece and Italy's water crisis can be well solved by coastal reservoirs, especially for their islands. Spain's water diversion from north to south should connect the coastal reservoirs, not the dams. Coastal reservoirs at the Thames and Seine river mouths can supply sufficient, high-quality water to London and Paris. Compared with dams and desalination plants used in Europe, coastal reservoirs have minimum environmental/social impacts. The Cardiff coastal reservoirs and those in Netherlands have demonstrated their positive impacts for urban regeneration and flood control.
With the recent warming trend over Europe and the Arctic, the Nordic regions have experienced more frequent and damaging extreme hydrological events which are anticipated to increase towards the end of the 21st century. Despite explicit trends, large variations have been observed across basins and regions when it comes to precipitation and floods hinting at a strong natural hydroclimatic variability that further complicates any assessment of potential future changes. In this study, we aim to better understand how climate variability links with the current extremes and future projections of floods in Norway in the context of the last millennium and the future. Specifically, we simulate over 1000 years (850-2099) daily discharge and floods at 34 catchments over five regions of Norway from the last millennium (including a warm period and a cold period; 850-1849) to the end of the 21st century by an ensemble model-chain method including four global climate models (GCMs), two bias-correction methods and two hydrological models. The modelling results show (i) all GCMs except MIROC-ESM simulate a higher mean temperature in Medieval Climate Anomaly (MCA) period than Little Ice Age (LIA) period, while simulated annual precipitation varies a lot in different GCMs and catchments, (ii) no significant change of flood characteristics during the last millennium from ensemble-mean results, (iii) in future, we will have an extraordinary shift in flood seasonality and generating processes, and flood frequency increase in most of the study catchments in Norway, and (iv) climate projections represent the largest contribution to overall uncertainty in the projected changes in hydrological extremes for most of the catchments.
This study investigates the combined impacts of climate change and agricultural conservation on the magnitude and uncertainty of nutrient loadings in the Maumee River Watershed, the second‐largest watershed of the Laurentian Great Lakes. Two scenarios — baseline agricultural management and increased agricultural conservation — were assessed using an ensemble of five Soil and Water Assessment Tools driven by six climate models. The increased conservation scenario included raising conservation adoption rates from a baseline of existing conservation practices to feasible rates in the near future based on farmer surveys. This increased adoption of winter cover crops on 6%–10% to 60% of cultivated cropland; subsurface placement of phosphorus fertilizers on 35%–60% to 68% of cultivated cropland; and buffer strips intercepting runoff from 29%–34% to 50% of cultivated cropland. Increased conservation resulted in statistically significant (p ≤ 0.05) reductions in annual loads of total phosphorus (41%), dissolved reactive phosphorus (18%), and total nitrogen (14%) under the highest emission climate scenario representative concentration pathway (RCP 8.5). While nutrient loads decreased with increased conservation relative to baseline management for all watershed models, different conclusions on the true effectiveness of conservation under climate change may be drawn if only one watershed model was used.
In this study, we assessed the impacts of uncertainties arising from hydrologic model parameters and climate change data on streamflow and catchment-level non-floodplain wetland (NFW) water storage predictions for the Coastal Plain of the Chesapeake Bay watershed. The hydrologic model used in this study was the Soil and Water Assessment Tool (SWAT) coupled with improved wetland modules. Model uncertainty was represented using 12 parameter sets (PARs) with acceptable model performance. Different projections of future climate conditions (eight global circulation models [GCMs] under three representative concentration pathways [RCPs]) were used to represent climate change uncertainty. The ensemble method and analysis of variance were adopted for uncertainty assessment. The results showed that monthly streamflow projections did not substantially differ with respect to individual PARs, GCMs, and RCPs; by contrast, the projected NFW water storage varied significantly. However, the changes in projected hydrological values relative to historic conditions greatly differed with regard to the PARs, GCMs, and RCPs, leading to a high uncertainty in assessing climate change impacts. The variability of GCM projections was the most significant single contributor, accounting for 46% and 49% of the total streamflow and NFW water storage projection uncertainties, respectively, followed by PARs and RCPs. Our work assessed the impacts of different uncertainty sources on NFW hydrology under climate change, suggesting careful consideration of model and climate change uncertainties for the reliable projections of NFW hydrologic behaviors.
The predicted climate change may introduce more stress and need various adaptation strategies to be implemented. Climate change in the Indian context has caused an increase in surface temperature at the rate of 0.2 ℃ per decade from 1971 to 2007. The present work is done to assess the impact of climate change through review of literatures pertaining to it.
Recent advancements in catchment hydrology (such as understanding hydrological processes, accessing new data sources, and refining methods for parameter constraints) make it possible to apply catchment models for ungauged basins over large domains. Here we present a cutting-edge case study applying catchment-modelling techniques at the global scale for the first time. The modelling procedure was challenging but doable and even the first model version show better performance than traditional gridded global models of river flow. We used the open-source code of the HYPE model and applied it for > 130 000 catchments (with an average resolution of 1000 km2), delineated to cover the Earths landmass (except Antarctica). The catchments were characterized using 20 open databases on physiographical variables, to account for spatial and temporal variability of the global freshwater resources, based on exchange with the atmosphere (e.g. precipitation and evapotranspiration) and related budgets in all compartments of the land (e.g. soil, rivers, lakes, glaciers, and floodplains), including water stocks, residence times, interfacial fluxes, and the pathways between various compartments. Global parameter values were estimated using a step-wise approach for groups of parameters regulating specific processes and catchment characteristics in representative gauged catchments. Daily time-series (> 10 years) from 5338 gauges of river flow across the globe were used for model evaluation (half for calibration and half for independent validation), resulting in an average monthly KGE of 0.4. However, the world-wide HYPE (WWH) model shows large variation in model performance, both between geographical domains and between various flow signatures. The model performs best in Eastern USA, Europe, South-East Asia, and Japan, as well as in parts of Russia, Canada, and South America. The model shows overall good potential to capture flow signatures of monthly high flows, spatial variability of high flows, duration of low flows and constancy of daily flow. Nevertheless, there remains large potential for model improvements and we suggest both redoing the calibration and reconsidering parts of the model structure for the next WWH version. The calibration cycle should be repeated a couple of times to find robust values under new fixed parameter conditions. For the next iteration, special focus will be given to precipitation, evapotranspiration, soil storage, and dynamics from hydrological features, such as lakes, reservoirs, glaciers, and floodplains. This first model version clearly indicates challenges in large scale modelling, usefulness of open data and current gaps in processes understanding. Parts of the WWH can be shared with other modellers working at the regional scale to appreciate local knowledge, establish a critical mass of experts and improve the model in a collaborative manner. Setting up a global catchment model has to be a long-term commitment of continuous model refinements to achieve successful and truly useful results.
The main equilibrium changes in climate, due to doubling CO 2, deduced from models are given below: Near the Earth's surface the global average warming lies between 1.5°C and 4.5°C, with a "best guess' of 2.5°C. There is much greater effect in high latitudes, than in the tropics. At the same time, the stratosphere cools. Global average precipitation (and evporation) increases by 3% to 15%. The area of sea-ice and seasonal snow cover diminish. -J.F.Austin
Different methods for automatically classifying river flow regimes have been investigated. The methods use monthly data and include procedures based on the timing of maximal and minimal flow. The paper also investigates the stability of flow regime types in time and provides a broad interpretation of spatial patterns in monthly flow regimes across northern and western Europe. It also takes up the problem of presentation of the results on a regular grid and considers how the regime types can be assigned to grid cells without observations.
Greenland ice-core data have revealed large decadal climate variations over the North Atlantic that can be related to a major
source of low-frequency variability, the North Atlantic Oscillation. Over the past decade, the Oscillation has remained in
one extreme phase during the winters, contributing significantly to the recent wintertime warmth across Europe and to cold
conditions in the northwest Atlantic. An evaluation of the atmospheric moisture budget reveals coherent large-scale changes
since 1980 that are linked to recent dry conditions over southern Europe and the Mediterranean, whereas northern Europe and
parts of Scandinavia have generally experienced wetter than normal conditions.
A new set of greenhouse gas emissions scenarios has been produced by the Intergovernmental Panel on Climate Change (IPCC). Incorporating these into models that also include the effects of C02 fertilization, feedback from stratospheric ozone depletion and the radiative effects of sulphate aerosols yields new projections for radiative forcing of climate and for changes in global-mean temperature and sea level. Changes in temperature and sea level are predicted to be less severe than those estimated previously, but are still far beyond the limits of natural variability.
A high-resolution (2.75{degrees} lat x 3.75{degrees} long) coupled ocean-atmosphere model has been used to simulate the transient response of climate to a gradual increase in atmospheric carbon dioxide concentrations. Although the radiative forcing increases linearly, there is a delay of about 30 yr before the ocean warms appreciably. This {open_quotes}cold start{close_quotes} is, at least partly, an artifact of the experimental design. At the time of doubling (after 70 yr), the patterns of change are similar to those found in comparable studies of the equilibrium response, except in the high latitudes of the Southern Ocean and the North Atlantic, where the warming is considerably reduced. The mechanisms leading to this reduction are discussed. After two to three decades, the pattern of warming is well established. The warming over land is substantially larger than that over the sea, with a consequent lowering of surface pressure over the northern continents in summer. The patterns of changes in precipitation and soil moisture take longer to establish themselves, although locally there are consistent changes after the third decade. 55 refs., 30 figs., 6 tabs.
A 1961–1990 mean monthly climatology for a ‘greater European’ region extending from 32°W to 66°E and from 25° to 81°N has been constructed at a resolution of 0.5°latitude by 0.5° longitude for a suite of nine surface climate variables: minimum, maximum, and mean air temperature; precipitation totals; sunshine hours; vapour pressure; wind speed; and (ground) frost day and rain day ( > 0.1 mm) frequencies. This climatology has been constructed from observed station data distributed across the region. Station frequencies range from 936 (wind speed) to 3078 (precipitation). Over 95 per cent of these data are based on observations between 1961 and 1990 and over 90 per cent were supplied by individual national meteorological agencies (NMAs) on specific request. For four variables, some standardization of the data had to be performed because different countries supplied data under different definitions. Thus cloud cover had to be converted to sunshine hours, relative humidity to vapour pressure, air frost days to ground frost days and rain days > 1 mm to rain days > 0.1 mm.
The interpolation of the station data to the grid used elevation as one of the predictor variables and thus enabled three climate surfaces to be produced for each variable, reflecting the minimum, mean, and maximum elevation within each 0.5° by 0.5° cell. Subsets of stations were used for the interpolation of each variable, the selection being based on optimizing the spatial distribution, source priority and length of record. The accuracy of the various interpolations was assessed using validation sets of independent station data (i.e. those not used in the interpolation). Estimated mean absolute errors (MAE) ranged from under 4 per cent for vapour pressure to about 10 per cent for precipitation and up to 20 per cent for wind speed. The accuracy of the interpolated surfaces for minimum and maximum temperature was between 0.5°C and 0.8°C.
We believe these results constitute the first climatology that has been constructed for this extensive European region at such a fine spatial resolution (0.5° by 0.5°) from relatively dense station networks, for three different elevation surfaces and for a wide range of surface climate variables, all expressed with respect to a standard 30‐year period. The climatology is already being used by researchers for applications in the areas of ecosystem modelling, climate change impact assessment and climate model validation, and is available from the authors.
This study describes a new coupled ocean-atmosphere general circulation model (OAGCM) developed for studies of climate change
and results from a hindcast experiment. The model includes various physical and technical improvements relative to an earlier
version of the Hadley Centre OAGCM. A coupled spinup process is used to bring the model to equilibrium. Compared to uncoupled
spinup methods this is computationally more expensive, but helps to counter climate drift arising from inadequate sampling
of short time scale coupled variability when the components are equilibrated separately. Including sea ice advection and enhancing
reference surface salinities in high southern latitudes in austral winter to promote bottom water formation during spinup
appears to have stabilized the high-latitude drift exhibited in the earlier model’s control run. In the present study, the
atmospheric control climate is stable on multi-century time scales with a drift in global average surface air temperature
of only +0.016 K/century, despite a small residual drift in the deep ocean. The control climate is an improvement over the
earlier model in several respects, notably in its variability on short time scales. Two anomaly runs are presented incorporating
estimated forcing changes over the period 1860 to 1990 arising from greenhouse gases alone and from greenhouse gases plus
the radiative scattering effect of sulphate aerosols. These allow validation of the model against the instrumental climate
record. Inclusion of aerosol forcing gives a significantly better simulation of historical temperature patterns, although
comparisons against recent sea ice trends are equivocal. These studies emphasize the potential importance of including additional
forcing terms apart from greenhouse gases in climate simulations, and refining estimates of their spatial distribution and
magnitude.
Introduction -- Africa -- The Arctic and the Antarctic -- Australasia -- Europe -- Latin America -- Middle East and Arid Asia -- North America -- Small Island States -- Temperate Asia -- Tropical Asia -- Annexes En port.: A Special Report of IPCC Working Group II. Published for the Intergovernmental Panel on Climate Change
5—23 Fig. 5. Change in the month of maximum runoff by 2050: UKTR, UKHI, CCC and GHGx scenarios A macro-scale hydrological model for the simula-tion of streamflow over a large geographic domain
- N W Arnell
N.W. Arnell / Global Environmental Change 9 (1999) 5—23 Fig. 5. Change in the month of maximum runoff by 2050: UKTR, UKHI, CCC and GHGx scenarios. N.W. Arnell / Global Environmental Change 9 (1999) 5—23 References Arnell, N.W., 1998, A macro-scale hydrological model for the simula-tion of streamflow over a large geographic domain. Journal of Hydrology (submitted).
Decadal trends in the North Atlantic Oscillation: regional temperature and precipitation The second Hadley Centre coupled ocean-atmosphere GCM: model description, spinup and validation
- J Hurrell
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- T C Johns
- R E Carnell
- J F Crossley
Hurrell, J., 1995, Decadal trends in the North Atlantic Oscillation: regional temperature and precipitation. Science 269, 676—679. Johns, T.C., Carnell, R.E., Crossley, J.F. et al., 1997. The second Hadley Centre coupled ocean-atmosphere GCM: model description, spinup and validation. Climate Dynamics 13, 103—134.
Impacts of anthropogenic climate change in relation to multi-decadal natural climate variability: examples from Europe
- M Hulme
- E Barrow
- N W Arnell
- P Harrison
- T C Johns
- T E Down-Ing
Hulme, M., Barrow, E., Arnell, N.W., Harrison, P., Johns, T.C., Down-ing, T.E., 1998. Impacts of anthropogenic climate change in relation to multi-decadal natural climate variability: examples from Europe.