Regional Drought Risk in the Contiguous United States

Apurv, Tushar; Cai, Ximing

doi:10.1029/2020gl092200

Cited by 22 publications

(14 citation statements)

References 88 publications

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“…Previous studies have attempted to capture the change in drought parameters during the drought propagation process by comparing the cumulative distribution functions of different types of droughts [15,16,19,20]. Apurv et al [15] suggested that the drought propagation process can be quantified by a ratio such as the drought propagation ratio, as shown in Equation (7) and Equation ( 8 However, the drought propagation ratios above can only capture the difference in the distribution of drought parameters, while the difference in the frequency of drought events is not considered.…”

Section: Drought Propagationmentioning

confidence: 99%

“…𝑇 𝑗 is the corresponding return period, t is the total time length of the study period (67 years), 𝑛 𝑠 and 𝑛 𝑚 are the numbers of soil moisture droughts and meteorological droughts, respectively. Drought propagation ratios are regarded as constant features of basins in previous studies and are determined by climate features and underlying properties [20]. Since the regional climate and underlying surface might change during the study period, the propagation ratios are also calculated by a moving-window method (see Section 3.5 for details).…”

Section: Drought Propagationmentioning

confidence: 99%

“…Apurv and Cai [20] applied a set of 30-year moving windows to capture the potential drought risks in the United States, with the precipitation in each moving window generated from the rainfall series in the moving window. Here, we also use 30-year moving windows to represent the change in drought characteristics.…”

Section: Temporal Analysis Of Historical Droughtsmentioning

confidence: 99%

“…Apurv and Cai [19] estimated the stationarity of historical droughts in the United States since 1901 and found increasing meteorological drought risks since 1901 in the southeastern US and California. Apurv and Cai [20] supposed an unchanged trend in the near future and estimated the corresponding trends of soil droughts, streamflow droughts, and water supply droughts, suggesting that the southwestern US will suffer severe water deficits in all of the drought types. However, the drought propagation is herein supposed to be unchanged.…”

Section: Introductionmentioning

confidence: 99%

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Spatiotemporal Characteristics of Droughts and Their Propagation during the Past 67 Years in Northern Thailand

Zhao

Yang

et al. 2022

Atmosphere

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Droughts grow concurrently in space and time; however, their spatiotemporal propagation is still not fully studied. In this study, drought propagation and spatiotemporal characteristics were studied in northern, northeastern, and central Thailand (NNCT). The NNCT is an important agricultural exporter worldwide, and droughts here can lead to considerable pressure on the food supply. This study investigated meteorological drought and soil drought in northern Thailand and identified 70 meteorological drought events and 44 soil drought events over 1948–2014. Severe droughts (droughts with long trivariate return periods) mainly occurred after 1975 and were centered in northern and northeastern Thailand. Meteorological drought and soil drought that occurred during 1979–1980 had the longest trivariate return periods of 157 years and 179 years, respectively. The drought centers were mainly located in the Chao Phraya River basin and the Mun River basin. The mean propagation ratios of all drought parameters (duration, area, severity) were lower than 1, indicating that the underlying surface can serve as a buffer to alleviate water deficits. Most of the probability distribution coefficients and all drought propagation ratios of the three drought parameters were found to change significantly based on a moving-window method, indicating that the drought parameters and propagation from meteorological drought to soil drought were non-stationary. Significant increasing trends were detected in mean values of most drought parameters, ranging from 2.4%/decade to 16.6%/decade. Significant decreasing trends were detected in coefficients of skewness (Cs) of all drought parameters and coefficients of variation (Cv) of most drought parameters, ranging from −3.3 to −12.4%/decade, and from −5.5 to −19.4%/decade, respectively. The propagation ratios of all drought parameters showed significant increasing trends, indicating that the function of the underlying surface as a buffer has become weaker. The drought propagation ratios were found to be positively related to two climate indices, the phase index (PI) and the climate seasonality index (CSI). These findings will help to develop a better understanding and management of water resources in Thailand.

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Section: Drought Propagationmentioning

confidence: 99%

Section: Drought Propagationmentioning

confidence: 99%

Section: Temporal Analysis Of Historical Droughtsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spatiotemporal Characteristics of Droughts and Their Propagation during the Past 67 Years in Northern Thailand

Zhao

Yang

et al. 2022

Atmosphere

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“…The changing climate may not influence the snowpack accumulation, melt and subsequent runoff uniformly [12]. Since these drier conditions are leading to a more uncertain future [13,14], an understanding of the spatial distribution of the snowpack is vital for management of water resources [15]. Spatial patterns of snow distribution have been considered at various scales [16] from local [17] to regional [18].…”

Section: Introductionmentioning

confidence: 99%

Snow Water Equivalent Accumulation Patterns from a Trajectory Approach over the U.S. Southern Rocky Mountains

et al. 2021

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The spatial characteristics and patterns of snow accumulation and ablation inform the amount of water stored and subsequently available for runoff and the timing of snowmelt. This paper characterizes the snow accumulation phase to investigate the spatiotemporal snow water equivalent (SWE) distribution by fitting a function to the trajectory plot of the standard deviation versus mean SWE across a domain. Data were used from 90 snow stations for a 34-year period across the Southern Rocky Mountains in the western United States. The stations were divided into sub-sets based on elevation, latitude, and the mean annual maximum SWE. The best function was a linear fit, excluding the first 35 mm of SWE. There was less variability with SWE data compared to snow depth data. The trajectory of the accumulation phase was consistent for most years, with limited correlation to the amount of accumulation. These trajectories are more similar for the northern portion of the domain and for below average snow years. This work could inform where to locate new stations, or be applied to other earth system variables.

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Interannual controls on riparian plant health in a dryland river

Downs,

Lambert,

Williams

et al. 2024

Ecohydrology

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Riparian zones in drylands provide important refugia for plants but depend on groundwater and thus are subject to local temporal and spatial variability in abiotic controls. In lieu of costly field‐based sampling, we used readily available data to establish site–scale interannual relationships among riparian plant health and the abiotic factors that control their water balance for a historically persistent wetland adjoining the Santa Clara River in southern California, USA. Non‐linear generalized additive model (GAM) analysis of plant health, represented using the normalized difference vegetation index (NDVI), confirmed robust relationships among plant health and various geomorphological and hydrological factors over multi‐decadal timeframes, including years since last high‐flow event, intra‐year groundwater elevation changes and magnitude of 2‐year cumulative surface water inflows. Geomorphic controls are related to years with high flows that cause extensive scour and deposition that re‐set riparian plant communities. Relationships with dry‐season groundwater declines reflect direct plant access to sub‐surface moisture. Hydrological dependence via cumulative inflow magnitude indicates the dependency of groundwater elevations on sufficient winter recharge to prevent precipitous groundwater decline. GAMs‐based inflection point analysis of surface water inflows versus groundwater elevations confirmed that the cumulative magnitude of multi‐year inflows is critical in avoiding catastrophic groundwater declines and that large flood events drive groundwater recovery. We show that abiotic controls on plant health can be derived from readily available data and that non‐linear analysis better represents the complexity of these scalar controls. Our analysis has relevance for ecosystem management of human‐altered rivers and climate change adaptation.

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Regional Drought Risk in the Contiguous United States

Cited by 22 publications

References 88 publications

Spatiotemporal Characteristics of Droughts and Their Propagation during the Past 67 Years in Northern Thailand

Spatiotemporal Characteristics of Droughts and Their Propagation during the Past 67 Years in Northern Thailand

Snow Water Equivalent Accumulation Patterns from a Trajectory Approach over the U.S. Southern Rocky Mountains

Interannual controls on riparian plant health in a dryland river

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