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Topography map of southwestern China, while the dark dots show the locations of the meteorological stations, the thick pink lines are the basin boundaries and the thin dark lines are the main rivers.
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Climate extremes have and will continue to cause severe damages to buildings and natural environments around the world. A full knowledge of the probability of the climate extremes is important for the management and mitigation of natural hazards. Based on Mann–Kendall trend test and copulas, this study investigated the characteristics of precipitat...
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Owing to their essential influence on human society and natural environment exerted by inducing disasters, such as floods and droughts, further studies on precipitation extremes in China are needed. This study presents the regional frequency and spatial-temporal patterns of precipitation extremes in China based on a high-resolution (0.5∘ × 0.5∘) da...
Citations
... In the southwestern karst region of China, due to the slow rate of soil formation, coupled with severe soil erosion, results in shallower soil (Jiang et al., 2014;Kovačič and Ravbar, 2013). This region influenced by a subtropical monsoon climate, experiences abundant rainfall, intense evaporation, complex surface water processes, and issues such as drought, water shortage, and soil erosion (Liu et al., 2014). Fortunately, in the humid karst ecosystem, land cover can serve as a significant protective measure against soil erosion and other ecological problems. ...
... Most studies found that global warming has altered precipitation, and more extreme precipitation occurred in the early twenty-first century (Donat et al. 2016;Ficklin et al. 2022;Kosaka and Xie 2013;Li et al. 2022a). Extreme precipitation and increased evapotranspiration can increase the severity and frequency of flood or drought events (Liu et al. 2014;Yu et al. 2014), which then influence water yield ) and ecosystem function (von Buttlar et al. 2018;Zeppel et al. 2014). Improving understanding of hydrologic intensity can assist in evaluating the impact of extreme precipitation events on plant function and water cycle (Gu et al. 2022;Li et al. 2022b;Lian et al. 2022). ...
Climate change is expected to alter the hydrologic cycle through precipitation and evapotranspiration. The hydrologic intensity is more complex under climate change in high mountainous regions. The spatial and temporal patterns of hydrological intensity were analyzed. The results showed that the degree of annual variations of hydrological intensity increased between 2001 and 2015 compared to 1980 and 2000. The slope of hydrological intensification showed a significant downward trend along the elevation gradient from 1980 to 2000, but no significant elevation-dependent pattern existed from 2001 to 2015. The variation of hydrologic intensity in spring before 2000 and after 2000 was most significant, while the change of hydrologic intensity in summer was not significant. Precipitation, air temperature, net radiation, and vapor pressure deficit (VPD) were significantly correlated with the hydrological intensity before 2000, while only precipitation and air temperature were significantly correlated with hydrological intensity after 2000. The spatial correlation coefficient between hydrological intensity and vertically integrated moisture flux at different altitudes was distributed more homogeneity after 2000. Local meteorological factors and large-scale circulation can influence the elevation-dependent precipitation variation. Under climate change, more attention should be paid to no elevation-dependent changes in hydrological intensity and societal decision-making in mountainous regions.
... In this work, we find that spring drought had a significant worsen trend in ESWC during 1961-2020, which can be explained by a significant downward trend in precipitation and a significant increasing trend in temperature (Figs. 2 and 3). The changes in temperature and precipitation were consistent with the results of previous studies (Qin et al., 2010;Liu et al., 2014;Li, 2015;Lian et al., 2015;Cheng et al., 2019). In particular, these results from segmented models and PDFs indicate that spring drought became much more frequent and intensified in ESWC during recent decades especially after 2003 (Figs. 6 and 7). ...
Study region: Southwest China (97.4ºE~112.1ºE, 21.1ºN~34.3ºN), including Sichuan, Yunnan, Guizhou, Chongqing, and Guangxi provinces. Study focus: Meteorological droughts were likely to become much more frequent and intensified, posing a huge threat to food security, drinking water supply, ecological environment security, and sustainable development of economy and society. However, the spatial and temporal variations of seasonal droughts and its possible driving forces are still not fully understood. In this work, we deeply explored the spatial and temporal variations of spring drought in Southwest China and its possible teleconnection mechanisms during 1961-2020. New hydrological insights for the region: The rising temperature and reduced precipitation led to a significant worsen trend of spring drought in the eastern parts of Southwest China (ESWC) during 1961-2020. Significant abrupt changes of spring drought occurred in 2003, and spring drought became much more frequent and intensified especially after 2003 in ESWC. Spring drought evolutions were dominated by NAO, and were also affected by the coupling of TNA and AO in ESWC during 1961-2020. However, the significant worsen trend of spring drought during 2003-2020 in ESWC could be largely explained by the coupling influences of NAO, TNA, and PDO. These results can provide valuable information for agricultural production, water resource management, and especially the early warning and prediction of spring drought in Southwest China.
... The southwestern region of China, characterized by its unique Karst topography and fragile ecosystem, is a sensitive and vulnerable zone to climate change [36]. Influenced by complex terrain and monsoonal circulations, this area is prone to localized intense precipitation [37,38], making it one of the regions in China with the most significant local variations and complexities in rainfall patterns. ...
This study harnesses ground observation data collected between 1980 and 2021 and ERA5 hourly data to thoroughly implement trend and correlation analysis techniques to explore the spatiotemporal dynamic characteristics of daily and hourly extreme precipitation in the Sichuan Basin. The investigation delineates these characteristics and probes into the potential triggers of extreme hourly rainstorms. The findings unveil the following: (1) A general increase in extreme rainfall volume, contribution rate, intensity, and dispersion, along with a decline in frequency and proportion of rainstorm areas, indicating the concentration of daily-scale severe rainstorms. The basin’s edge receives more precipitation than the bottom, exhibiting latitudinal variations. (2) The northernmost mountainous regions have less frequent, less intense rainstorms influenced by terrain, whereas the northeastern region experiences more frequent, dispersed rainstorms. (3) Extreme hourly rainstorms predominantly occur at night, with rainfall amount, intensity, and frequency declining at 21:00 compared to 19:00. (4) Summer experiences the highest risk of extreme rainstorms, with annual and monthly datasets displaying a rising trend in the frequency, dispersion, and intensity of intense hourly rainstorms. (5) Peak values of extreme hourly rainstorms are growing, with two distinct periods for their frequency: 1:00–9:00 and 10:00–24:00, with an increase in the former and a decrease in the latter. (6) Normalized difference vegetation index (NDVI) values ascend from southwest to northeast within the basin on a ten-day scale, correlating with the distribution of hourly extreme precipitation.
... Additionally, the vegetation in dolomite or limestone areas has persisted predominantly as low shrubs or grasses for nearly two decades under natural restoration conditions. Moreover, the southwestern region has witnessed a continuous reduction in annual rainfall at a rate of 11.4 mm per decade over the past 60 years, thereby increasing the frequency of extreme drought and flood events, which further impedes the restoration of forest landscapes (Liu et al., 2014). ...
Over the past two decades, the karst region in southern China has emerged as a critical area for ecological conservation and restoration, attracting global attention for its efforts in ‘greening.’ However, particular areas face challenges transitioning into forests due to the carbonate bedrock constraint, which likely undermines sustainability of greening efforts in karst regions. This study overviews the significant achievements in vegetation restoration in the karst region of southwest China, emphasizing the potential of short-term ecological restoration in effectively sequestering carbon, a valuable approach to achieving carbon neutrality in the region. However, combating rocky desertification remains difficult due to geological limitations that hinder large-scale afforestation. Additionally, variations in soil and rock composition impact the success and quality of vegetation restoration, leading to some areas failing to establish forests. Therefore, establishing the goals for rocky desertification control in different regions (enhancement, degradation, or reduction) should be based on current conditions and the evolutionary characteristics of rocky desertification. To facilitate precise afforestation and grass planting in the karst region, factors such as climate, rock conditions, and human-environment relationships should be considered in regional divisions, including natural restoration zones, artificial afforestation zones, grass planting zones, and protected zones.
... Under climate change, the annual precipitation and rain days in SWC were decreasing (Qin et al. 2015;Liu and Xu 2016), but the extreme daily rainfall was increasing (Zhang et al. 2011;Luo et al. 2015). Similar trend analyses have also been conducted in specific regions of SWC, with a significant increase in daily extreme precipitation in Guizhou and Yunnan Liu et al. 2014). ...
Southwest China (SWC) possesses complicated topography with frequent geological activities, where heavy precipitation occurs frequently in warm seasons. Few previous studies on extreme precipitation were carried out at hourly scales. In this study, spatiotemporal variations of the extreme hourly precipitation (EHP) over SWC during the warm season of 1981–2020 and the involved mechanisms are investigated. Results show that the threshold and intensity of EHP present similar spatial distribution—lower (higher) in the west (east) part of SWC, while the EHP frequency is opposite. The long-term trend of EHP amount shows a more significant positive tendency than that of hourly precipitation (HP) amount due to synchronous increases in intensity and frequency. The significant increasing trend of EHP occurs in areas above 500-m terrain height, with a weak increasing trend below 500 m (e.g., Chongqing and eastern Sichuan). EHP appears mainly from June to August and exhibits a bimodal distribution in diurnal variation. The mechanism analysis demonstrates that occurrences of EHP are generally accompanied by positive anomalies of temperature, humidity, and geopotential height. Anomalous cyclonic circulation can also be found in the low-level wind field. The westward and northward extension of the western North Pacific subtropical high (WNPSH) as well as temperature rise may be the primary reason for the increase of EHP. For Chongqing and eastern Sichuan, the anticyclone circulation in low-level and the significantly weakened water vapor flux convergence cause poor moisture and dynamic conditions, inhibiting the growth of EHP.
Significance Statement
Heavy precipitation occurs frequently during the warm season in Southwest China (SWC), often causing severe impacts on human safety and economic property. This study analyses spatiotemporal variations of the extreme hourly precipitation (EHP) over SWC during the warm season of 1981–2020 and the involved mechanisms. The increasing trend of EHP far exceeds that of hourly precipitation (HP), especially in areas above 500 m. The westward and northward extension of the western North Pacific subtropical high (WNPSH) and temperature rise may be the main reason for the increase of EHP. For areas below 500 m (e.g., Chongqing and eastern Sichuan), poor moisture and dynamic conditions inhibited the growth of EHP.
... The frequency of extreme hourly precipitation nationwide has shown an increase of 0.7 h/10a; however, the overall trend in precipitation intensity remains insignificant across the country [7]. Liu et al. [8] also emphasized an increased risk of extreme wet and hot events in different regions of China. From 17 to 22 July 2021, Henan Province experienced a historically rare extreme, heavy precipitation event (referred to as the "7.20" ...
Precipitation products play an important role in monitoring rainstorm processes. This study takes a rare historical event of extreme, heavy precipitation that occurred in Henan Province, China, in July 2021 as a research case. By analyzing the distribution of the spatial and temporal characteristics of precipitation errors, using a probability density function of the occurrence of precipitation and the daily variation pattern, we assess the capability of a radar precipitation estimation product (RADAR), satellite precipitation products (IMERG and GSMAP), a reanalysis product (ERA5) and a precipitation fusion product (the CMPAS) to monitor an extreme rainstorm in the Henan region. The CMPAS has the best fit with the gauge observations in terms of the precipitation area, precipitation maximum and the evolution of the whole process, with a low spatial variability of errors. However, the CMPAS slightly underestimated the precipitation extremum at the peak moment (06:00–08:00). The RADAR product was prone to a spurious overestimation of the originally small rainfall, especially during peak precipitation times, with deviations concentrated in the core precipitation area. The IMERG, GSMAP and ERA5 products have similar performances, all of which failed to effectively capture heavy precipitation in excess of 60 mm/h, with negative deviations in precipitation at mountainfront locations west of northern Henan Province. There is still a need for terrain-specific error revisions for areas with large topographic relief. By merging and processing precipitation data from multiple sources, the accuracy of the CMPAS is better than any single-source precipitation product. The CMPAS has the characteristic advantage of high spatial and temporal resolutions (0.01° × 0.01°/1 h), which play a positive role in precipitation dynamic monitoring, providing early warnings of heavy rainfall processes and hydrological application research.
... Similarly, several studies have demonstrated the influence of forest clearance and urbanization on peak flows (Huang et al. 2008;Wei et al. 2018) and landslides (Goetz et al. 2015;Persichillo et al. 2017). Reforestation in mountainous regions is, therefore, paramount as they are landslide-prone regions and presented a trend to increase Rx1day and Rx5day (Aristizábal et al. 2011;Diakakis 2012;Liu et al. 2014;Wu et al. 2015). Therefore, it is suggested to make these areas a priority in reforestation programs that aim to maintain, recover, and expand forest cover such as the Reflorestar program (Benini et al. 2016). ...
Disasters caused by rainfall extremes represent social challenges in several sectors, especially in climate change scenarios. Along with changes in land use and land cover, this relationship may become more complex. Thus, the present study aimed to detect recent trends in the pattern of rainfall indicators and associate them with records of natural disasters and the evolution of changes in land use and land cover for the state of Espírito Santo, southeastern Brazil. Daily rainfall data from 77 rain gauge stations from 1970 to 2018 were used to analyze climate trends in different rainfall indicators obtained using the RClimDex software. Records of natural disasters from 1991 to 2020 in the state of Espírito Santo were gathered from the Brazilian Integrated Disaster Information System. Additionally, land use and land cover data from 1985 and 2019 were also used. The Mann-Kendall (MK) test and the Sen slope were used to detect and quantify trends. In the Litoral Norte Espírito-santense and Noroeste Espírito-santense mesoregions of the State, trends of drought intensification are expected mainly in the regions further north. Associated with the great recent agricultural expansion in the region, this trend is concerning. The Central Espírito-santense and Sul Espírito-santense mesoregions tend to become wetter, which explains the recent increase in floods and heavy rainfall. No significant trends were found in the other regions studied. The approach adopted in this study has the potential to assist decision-making, implement mitigation and/or adaptation measures, and reduce the impacts of natural disasters in different regions of the world.
... Nevertheless, because of the limited research scale, it remains unclear whether the soil microbial community patterns observed upon vegetation restoration are also relevant on a regional scale in karst areas. In addition, long-term continuous data indicated that the risk and severity degree of extreme weather events in Southwest China are increasing [33]. However, it is not clear how soil microbial communities respond to climate change in the karst region, which increases the difficulty of predicting the recovery performance of these ecologically fragile areas. ...
Managed and natural vegetation restorations are two vital measures of land restoration; however, their effects on soil microbial communities at a large scale are not clearly understood. Hence, changes in the microbial community composition after 15 years of vegetation restoration along a climatic gradient in the subtropical karst region of Southwest China were assessed based on phospholipid fatty acids (PLFAs) profiles. Managed (plantation forest) and natural (naturally recovered to shrubbery) vegetation restoration types were compared, with cropland and mature forest serving as controls. Soil microbial community abundance was significantly higher under the two vegetation restoration types than in the cropland; however, it was lower than in the mature forest. The abundance, composition, and structure of soil microbial communities did not differ significantly between plantation forest and shrubbery. Soil organic carbon or total nitrogen was the primary factor positively affecting soil microbial abundance, whereas the mean annual temperature (MAT) was recognized as the primary factor contributing to the variation in the soil microbial community structure. Moreover, temperature had opposite effects on different indicators of microbial community structure. That is, it positively and negatively affected the ratios of gram-positive to gram-negative bacterial PLFAs (GP:GN) and fungal to bacterial PLFAs (F:B), respectively. Our results show that both vegetation restoration types have the ability to improve soil productivity in karst areas. Furthermore, shifts in soil microbial community structure (GP:GN and F:B ratios) induced by warming are likely to lead to a higher proportion of labile carbon, which is sensitive to soil tillage. Hence, more attention should be paid to ecological restoration in warmer karst areas to alleviate the severe loss of soil carbon in croplands.
... The hydrological cycle is crucial for both natural ecosystems and the survival and development of humans (Li et al. 2014). Climate change and human activities have caused an accelerated global hydrological cycle, resulting in shifts in precipitation and evaporation distribution (Xu et al. 2013;Liu et al. 2014;Amin et al. 2017). Consequently, the study of variations in runoff has become essential. ...
Under the dual influences of precipitation and human activities, urban runoff has significantly changed. It is important to evaluate how precipitation characteristics and human activities may affect city runoff in the aspect of alleviating urban flooding problems. The impact of precipitation concentration and human activities on urban runoff was studied by hydro-statistical methods, to provide a scientific basis for the evolution regularity of urban runoff and the urban flood control. The investigation of sudden alterations in runoff was carried out utilizing two approaches—the method of Mann–Kendall test and the technique of double accumulation curve. Then, a regression model was used to analyze the relationship between the precipitation concentration and runoff during different periods. Using the SCRCQ method, we examined how changes in runoff are influenced by the concentration of precipitation and human activities. This research took Guangzhou city as a case study, analyzing the alteration in runoff from 1970 to 2020. The results indicated a rise in runoff of 132.9 mm between 2013 and 2020, attributable to the combined impacts of precipitation concentration and human activities. Specifically, human activities contributed to a runoff increase of 141.4 mm, while the decrease in precipitation concentration resulted in a runoff decrease of 8.5 mm. Human activities displayed a significant contribution rate of 94% to runoff, whereas the contribution rate of precipitation concentration was -6%. This research provides a scientific basis for alleviating urban floods.
