Marshall Shepherd

University of Georgia | UGA · Department of Geography

Climate‐driven disasters have disproportionate and often devastating consequences on individuals with disabilities. Warming ocean and air temperatures are fueling more extreme tropical cyclones, further endangering those living in at‐risk regions. Although hurricane preparedness is particularly critical for those with functional impairments and/or...

This handbook is currently in development, with individual articles publishing online in advance of print publication. At this time, we cannot add information about unpublished articles in this handbook, however the table of contents will continue to grow as additional articles pass through the review process and are added to the site. Please note...

Observational and numerical modeling studies continue to affirm the existence of the “urban rainfall effect” (URE), or a discernible anomaly in warm season precipitation due to urbanization. However, the literature has been lacking a progression towards the predictability of the URE. Atlanta, Georgia has consistently appeared in the literature beca...

Figure 4. WRF simulations of surface temperature (℃) in control (top left), NOURBAN (top right), and DCBAL (bottom) land cover modification schemes. Valid at 0000 UTC on 6 February 2004.

Figure 15. WRF-simulated lifting condensation level (LCL) height difference (m) from control (LCLmodified − LCLcontrol). Valid at 1200 UTC on 6 February 2004.

Figure 8. WRF-simulated air temperature (°C) and winds, u, (kt) in the control simulation at 1000, 925, 850, and 700 mb. Valid at 0000 UTC on 6 February 2004.

Urban modification of precipitation regimes is well documented in the urban climate literature. Studies investigating urbanization and non-convective precipitation, specifically winter precipitation, are limited. The theoretical framework here argues that the collective influence of urbanization extends beyond traditional city limits and the surrou...

Figure 9. WRF-simulated 925 mb (left, Column A) and 1000 mb (right, Column B) temperature difference (°C) from the control (Tmodified − Tcontrol). Valid at 0000 UTC on 6 February 2004.

Figure 13. Same as Figure 12 except zoomed into the lowest kilometer of the atmosphere for detail.

Figure 5. Observed domain Doppler (left) and WRF-simulated, control (right) reflectivity (dBZ) at 1800 UTC on 6 February 2004. Observed data courtesy of Iowa Environmental Mesonet.

Figure 10. WRF-simulated vertical atmospheric soundings at Philadelphia, PA over the control, NOURBAN, and PHLWIL simulations. Valid at 1000 and 1200 UTC on 6 February 2004. Black and blue lines are temperature and dewpoint (°C), respectively.

Figure 12. Vertical cross-section of WRF-simulated relative humidity (%) and air temperature, T, (°C) from southwest to northeast beginning in Northern Virginia and ending near Princeton, New Jersey. Dashed (solid) lines denote T < 0 °C (T > 0 °C); thick, black line denotes T = 0 °C. Valid at 0800 UTC on 6 February 2004.

Figure 7. WRF-simulated snow depth difference from the control (SnowDepthmodified − SnowDepthcontrol) over the masked urban grid points. Valid from 0000 UTC on 4 February to 2300 UTC on 8 February 2004.

Figure 11. Graphical depiction of the horizontal path for the WRF-simulated vertical cross-section (red line). Urban footprint (grey) and major cities (stars) are also shown.

Figure 1. (top) The domain of study, major cities, and regional urban footprint. (bottom) NOAA-operated atmospheric sounding sites over the Mid-Atlantic region in the United States.

Figure 2. Weather research and forecasting (advanced research WRF) computational domains. The outer domain extends the edge of the graphic and has a horizontal resolution of 10 km. The second and third domains have resolutions of 3.3 km and 1.1 km, respectively.

Figure 14. Same geographic template as Figure 13. Vertical cross-section anomalies of WRF-simulated relative humidity (%) and air temperature, T, (°C) (Xmodified − Xcontrol) from southwest to northeast beginning in northern Virginia and ending near Princeton, New Jersey. Dashed (solid) lines denote ΔT < 0 °C (ΔT > 0 °C); thick, black line denotes Δ...

Figure 3. Moderate resolution imaging spectroradiometer (MODIS) land cover classifications over the domain (shown via WRF output variable LU_INDEX). Yellow, cross-hatched areas highlight urban land surface type (MODIS land cover classification No. 13). The labels correspond to each respective urban cluster—DCBAL (A), PHLWIL (B), and NYC (C). Combin...

Figure 6. Comparison of 2-m temperature distribution over the masked urban grid points after precipitation onset in the domain. Valid period beginning at 1800 UTC on 5 February 2004.

The Brown Ocean Effect (BOE) is the observation that post-landfalling tropical cyclones strengthen or maintain intensity over moist surface, given a near-barotropic environment and sufficient latent heat flux release, emphasizing soil moisture. Under these conditions, the land surface imitates an ocean surface, which provides a moisture source. To...

Cyclone Kelvin made landfall in northwest Australia as a category 1 storm on 18 February 2018. After landfall, tropical cyclones typically weaken due to the exhaustion of a moisture supply. Cyclone Kelvin continued to intensify with winds gusting to 100 knots and significant flooding well inland. A distinct eye feature also formed well after landfa...

Inland flooding due to tropical cyclones (TCs) is a major hazard, accounting for 25-50% of related deaths since 1970. Inland wind damage is also not to be overlooked, which is responsible for over 10% of deaths prior to Hurricane Katrina. Therefore, understanding the land-atmosphere interactions is critical for assessing inland impacts of TCs. One...

Subnational entities are recognizing the need to systematically examine options for reducing their carbon footprints. However, few robust and comprehensive analyses are available that lay out how US states and regions can most effectively contribute. This paper describes an approach developed for Georgia—a state in the southeastern United States ca...

Tropical Storm Bill produced over 400 mm of rainfall to portions of southern Oklahoma from 16-20 June 2015, adding to the catastrophic urban and river flooding that occurred throughout the region in the month prior to landfall. The unprecedented excessive precipitation event that occurred across Oklahoma and Texas during May and June 2015 resulted...

Barriers to the application of climate science in land use planning are often understood as a problem related to perceived disciplinary knowledge gaps. This paper argues that, instead, limitations to the application of knowledge are not strictly linked to transference, but are also attributed to the thought processes that planners use to understand...

An investigation of TC Kelvin in February 2018 over northeast Australia was conducted to understand the mechanisms of the Brown Ocean effect (BOE), and to develop a comprehensive analysis framework for landfalling tropical cyclones (TCs) in the process. NASA’s Land Information System (LIS) coupled to the NASA Unified WRF (NU-WRF) system was employe...

While only a small fraction of the Earth’s total land cover, the majority of the world population resides in cities. Urbanization is critical to the social, political, and economic vibrancy of society, but it also has significant impacts on the environment. NASA-related satellite, modeling, and scientific resources have enabled a systems perspectiv...

The Brown Ocean Effect (BOE) is the observation that post-landfalling tropical cyclones strengthen over moist surface, given a near-barotropic environment and sufficient latent heat flux release, emphasizing soil moisture. Under these conditions, the land surface imitates an ocean surface, which provides a moisture source. Previous research has ind...

Extreme flooding over southern Louisiana in mid-August of 2016 resulted from an unusual tropical low that formed and intensified over land. We used numerical experiments to highlight the role of the ‘Brown Ocean’ effect (where saturated soils function similar to a warm ocean surface) on intensification and it’s modulation by land cover change. A nu...

Recent tropical cyclones (TCs) have highlighted the hazards that TC rainfall poses to human life and property. These hazards are not adequately conveyed by the commonly used Saffir–Simpson scale. Additionally, while recurrence intervals (or, their inverse, annual exceedance probabilities) are sometimes used in the popular media to convey the magnit...

The human population on Earth has increased by a factor of 4.6 in the last 100 years and has become more centered in urban environments. This expansion and migration pattern has resulted in stresses on the environment. Meteorological applications have helped to understand and mitigate those stresses. This chapter describes several applications that...

The 2009 Atlanta flood was a historic event that resulted in catastrophic damage throughout the metropolitan area. The flood was the product of several hydrometeorological processes, including moist antecedent conditions, ample atmospheric moisture, and mesoscale training. Additionally, previous studies hypothesized that the urban environment of At...

Climate change has far-reaching effects on human and ecological systems, requiring collaboration across sectors and disciplines to determine effective responses. To inform regional responses to climate change, decision-makers need credible and relevant information representing a wide swath of knowledge and perspectives. The southeastern U. S. State...

Climate change has far-reaching effects on human and ecological systems, requiring collaboration across sectors and disciplines to determine effective responses. To inform regional responses to climate change, decision-makers need credible and relevant information representing a wide swath of knowledge and perspectives. The southeastern U. S. State...

Although it is widely recognized that urbanization has a notable impact on streamflow characteristics, the relative influence of the extent, spatial configuration, and positioning of urban development on low, high, and peak flow regimes is still not fully understood. The overarching research objective of this study was to clarify these relationship...

The intensely active 2017 Atlantic basin hurricane season provided an opportunity to examine how climate drivers, including warming oceans and rising seas, exacerbated tropical cyclone hazards. The season also highlighted the unique vulnerabilities of populations residing on Small Island Developing States (SIDS) to the catastrophic potential of the...

Spatial metrics have emerged as a widely utilized tool to quantify urban morphologies and monitor urban sprawl. Since previous applications of spatial metrics have typically considered only a single urban class, this study evaluates how deriving spatial metrics from multiple land use/land cover (LULC) classification schemes can help elucidate the s...

Spatio-temporal patterns in mean and extreme rainfall are examined around the city of Atlanta, Georgia using the Multi-sensor Precipitation Estimates (MPE) and ERA-Interim reanalysis datasets. The analysis spans the period 2002 to 2015 and employs a 9-cell gridded framework centered on downtown Atlanta. Statistically significant anomalies in daily...

A major thunderstorm asthma epidemic struck Melbourne and surrounding Victoria, Australia, on 21 November 2016, which led to multiple deaths, a flood of residents seeking medical attention for respiratory problems, and an overwhelmed emergency management system. This case day had all the classic ingredients for an epidemic, including high rye grass...

In several regions of the world, tropical cyclones have been known to maintain or increase strength after landfall without transitioning to extratropical systems. It is hypothesized that these inland areas help sustain tropical cyclones when there has been plentiful rainfall, leading to unusually wet soil and strong latent heat release. Additionall...

The relationship between rainfall characteristics and urbanization over the Eastern US was examined by analyzing four datasets: daily rainfall in 4,593 surface stations over the last 50 years (1958-2008), a high resolution gridded rainfall product, reanalysis wind data, and a proxy for urban land-use: gridded human population data. Results indicate...

Atmospheric rivers (ARs) are narrow and elongated bands of anomalous water vapour transport that have been widely studied due to their notable influence on regional weather patterns, surface hydrology, and the global water cycle. Although ARs produce a relatively large proportion of the annual precipitation in the southeastern quadrant of the Unite...

This study maps the spatial and temporal evolution of acres irrigated in the Coastal Plain of Georgia over a 38 year period. The goal of this analysis is to create a time-series of irrigated areas in the Coastal Plain of Georgia at a sub-county level. From 1976 through 2013, Landsat images were obtained and sampled at four year intervals to manuall...

We use the Northeast US Urban Climate Archipelago as a case study to explore three key limitations of planning and policy initiatives to mitigate extreme urban heat. These limitations are: (1) a lack of understanding of spatial considerations-for example, how nearby urban areas interact, affecting, and being affected by, implementation of such poli...

Roughly one third of U.S. greenhouse gas emissions are travel-related, and much of these are from routine, short trips that can be controlled by individual consumers. Because of this, sustainability advocates encourage greater use of alternative transportation modes such as mass transit and non-motorized transport to help limit carbon dioxide emiss...

Inflatable bounce houses provide a popular summer activity for children. Injuries such as sprains and fractures are widely acknowledged, but there is less awareness about possible hazards from excessive heat exposure. This study aims to identify whether conditions in the bounce house are more oppressive than ambient conditions on a typical summer d...

If you follow climate news or have climatologist friends like we do, you will have noted the successful end of the Paris Conference of Parties (COP21) meeting in mid-December. As the supreme decision making body of the United Nation’s Framework Convention on Climate Change (UNFCCC), the Conference of Parties is a central actor in international clim...

Flooding is routinely one of the most deadly weather-related hazards in the United States, which highlights the need for more hydrometeorological research related to forecasting these hazardous events. Building upon previous literature, a synergistic study analyzes hydrometeorological aspects of major urban flood events in the United States from 19...

The year 2015 is notable for the coincidence of several strong climate indicators that having bearing on the occurrence and intensity of tropical cyclones worldwide. This year, 2015, is clearly on track to become the warmest on record in terms of global temperatures. During the latter half of 2015, a very strong El Nino has formed and is predicted...

Climate change is one of the most challenging geophysical science and policy issues in modern times. The combined anthropogenic and natural forcing on the climate have profound impacts on the major spheres of the Earth system. Scholarly analysis has also revealed a cascading array of effects on the socio-economic and political fabric. One of the mo...

Climate change is occurring in the Southeastern United States, and one manifestation is changes in frequency and intensity of extreme events. A vulnerability assessment is performed in the state of Georgia (United States) at the county level from 1975 to 2012 in decadal increments. Climate change vulnerability is typically measured as a function of...

We combine Landsat and MODIS data in a land model to assess the impact of urbanization on US surface climate. For cities built within forests, daytime urban land surface temperature (LST) is much higher than that of vegetated lands. For example, in Washington DC and Atlanta, daytime mean temperature differences between impervious and vegetated land...

Recent upward trends in acres irrigated have been linked to increasing near-surface moisture. Unfortunately, stations with dew point data for monitoring near-surface moisture are sparse. Thus, models that estimate dew points from more readily observed data sources are useful. Daily average dew temperatures were estimated and evaluated at 14 station...

The localized rain rate maxima (R M) of the inner core region of intense tropical cyclones (TCs) are investigated using Version 6 of the Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis data-set from 1998 to 2010. Specifically, this study examines the probabilities of R M exceeding 25 mm h−1 (P25) in intense TCs. The 25 mm...

Drawing on megapolitan geographies, urban political ecology, and urban metabolism as theoretical frameworks, this article theoretically and empirically explores megapolitan political ecology. First, we elucidate a theoretical framework in the context of southern Appalachia and, in particular, the Piedmont megapolitan region, suggesting that the meg...

Superstorm Sandy was an unprecedented meteorological event that devastated the Caribbean and the Northeastern Coast of the USA in October 2012. While many research efforts will focus on the atmospheric conditions that led to the creation and unusual track of the storm, this study evaluates the impact of Sandy on voter turnout in the 2012 US Preside...

In late October 2012, an extreme area of high pressure centred near Greenland, known as a ‘Greenland block’, forced Hurricane Sandy to turn westward into the Northeast coast of the United States. In light of this unusual and catastrophic event, the Greenland blocking conditions associated with Sandy and previous North Atlantic hurricane tracks are...

Extreme heat is the leading weather-related killer in the United States. Vulnerability to extreme heat has previously been identified and mapped in urban areas to improve heat morbidity and mortality prevention efforts. However, only limited work has examined vulnerability outside of urban locations. This study seeks to broaden the geographic conte...

Satellite-based precipitation data are a viable source of information in data-sparse regions and are particularly valuable for hydrological modelling applications. Several studies of satellite-based precipitation focus on monthly or greater timescales, but a relatively fewer number have been done on the daily or sub-daily scales. Also, biases in sa...

Land cover changes (LCCs) play an important role in the climate system. Research over recent decades highlights the impacts of these changes on atmospheric temperature, humidity, cloud cover, circulation, and precipitation. These impacts range from the local- and regional-scale to sub-continental and global-scale. It has been found that the impacts...

Forecasting tropical cyclone (TC) intensity changes over land is complicated by interactions of various surface and atmospheric features. Due to generally unfavorable conditions, many TCs weaken and decay soon after landfall. In some cases, TCs may also transition to extratropical cyclones (ETs). Despite the absence of oceanic forcing, a number of...

Megacities of South Asia face the challenges of decreasing recharge and dwindling ground water resources because of rapid urbanization, high population growth, and rural-to-urban migration. Sustainable approaches for water resources in the future should account for such trends and patterns in the context of increasing urbanization, imperviousness,...

Tropical cyclones (TCs) typically weaken or transition to extratropical cyclones after making landfall. However, there are cases of TCs maintaining warm-core structures and intensifying inland unexpectedly, referred to as TC maintenance or intensification events (TCMIs). It has been proposed that wet soils create an atmosphere conducive to TC maint...

This chapter was originally published in the book Climate Vulnerability. The copy attached is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research, and educational use. This includes without limitation use in instruction at your institution, distribution to specific colleagues, a...

Atmospheric warming and associated hydrological changes have implications for regional flood intensity and frequency. Climate models and hydrological models have the ability to integrate various contributing factors and assess potential changes to hydrology at global to local scales through the century. This survey of floods in a changing climate r...

Validation of North American Regional Climate Change Assessment Program (NARCCAP) climate simulations is conducted for selected US Forest Service sites in the southeastern United States. Results focus on qualitative and quantitative comparisons of seasonal and monthly temperature data from NARCCAP simulations to the surface air temperature data set...

Empirical and modelling studies show that urbanization can have an impact on the environment. Relatively few studies have investigated urban effects on precipitation in India or other developing countries experiencing rapid urbanization. Furthermore, most precipitation-related studies for India focus on monsoonal rainfall. However, premonsoonal per...

In October 2010, the water level upstream of the Three Gorges Dam (TGD) reached the designated 175-m level. The associated inundation and land use-land cover changes have important implications for water resource management, agriculture, ecosystems, and the hydroclimate. Ultimately, it is important to quantify whether the dam-related changes have a...

Urban–coastal circulations affect urban weather, dispersion and transport of pollutants and contaminants, and climate. Proper characterization and prediction of thermodynamic and dynamic processes in such environments are warranted. A new generation of observation and modeling systems is enabling unprecedented characterization of the three-dimensio...

The world has seen, and is still seeing the rapid development and spread of urban areas. Cities and towns have sprouted up every where around the globe. Villages are transforming into towns and towns into cities, attracting more and more people, and adding to urban expansion. Population increase and industrialization are the key factor behind such...

Marshall Shepherd, professor of geography in the University of Georgia's Franklin College of Arts and Sciences, Athens, began a 1-year term as president-elect of the American Meteorological Society (AMS) on 22 January. In 2013 he will assume the presidency of the society. Also, five AGU members recently were elected as AMS councilors, with terms ex...

Two surface temperatures have been used in global change studies - 2-m surface air temperature (Tair) and skin temperature (Tskin). Skin temperature provides additional new information about the Earth surface because its physical meaning and magnitude differ from Tair. We will present two examples to reveal the advantages of using Tskin in studying...

An overview of synoptic and mesoscale factors contributing to the disastrous Atlanta flood of 2009 is presented. The 100-yr flood level with a 1% chance of occurrence in any given year is one of the standards that the Federal Emergency Management Agency (FEMA) uses to set flood insurance rates and prevent flood plain development. The cooperative ob...

• Carbon dioxide levels do show natural variability, but only since the industrial revolution have values moved beyond the "natural bound" of 270 to 280 ppm. Current levels are approximately 390 ppm. • Global livestock production 1) appropriates around 3% of global net primary productivity, 2) leads to collateral carbon flows such as losses to the...

In response to the Chief of Naval Operations (CNO), the National Research Council appointed a committee operating under the auspices of the Naval Studies Board to study the national security implications of climate change for U.S. naval forces. In conducting this study, the committee found that even the most moderate current trends in climate, if c...

A radar-based climatology of 91 unique summertime (May 2000-August 2009) thunderstorm cases was examined over the Indianapolis, Indiana, urban area. The study hypothesis is that urban regions alter the intensity and composition/structure of approaching thunderstorms because of land surface heterogeneity. Storm characteristics were studied over the...

Many regions of the world have limited meteorological or hydrological data for use in watershed analysis and modeling. This makes it difficult to obtain input and calibration datasets for effective modeling. Satellite-based and reanalysis meteorological data provide spatially and temporally distributed inputs for hydrologic analysis and are availab...

An accidental tritium release (570 L, 210 TBq) from the K-Reactor at the Savannah River Site (South Carolina, USA) occurred between December 22-25, 1991. Observed tritium concentrations in rivers and streams, as well as in the coastal estuary, are used to calibrate a hydrologic flow and transport model, BASINS 4.0 (Better Assessment Science Integra...

1] Understanding the forcings exerted by large dams on local climate is key to establishing if artificial reservoirs inadvertently modify precipitation patterns in impounded river basins. Using a 30 year record of reanalysis data, the spatial gradients of atmospheric variables related to precipi-tation formation are identified around the reservoir...