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Acute and chronic water scarcity impacts four billion people, a number likely to climb with population growth and increasing demand for food and energy production. Chronic water insecurity and long-term trends are well studied at the global and regional level; however, there have not been adequate systems in place for routinely monitoring acute water scarcity. To address this gap, we developed a monthly monitoring system that computes annual water availability per capita based on hydrologic data from the Famine Early Warning System Network (FEWS NET) Land Data Assimilation System (FLDAS) and gridded population data from WorldPop. The monitoring system yields maps of acute water scarcity using monthly Falkenmark classifications and departures from the long-term mean classification. These maps are designed to serve FEWS NET monitoring objectives; however, the underlying data are publicly available and can support research on the roles of population and hydrologic change on water scarcity at sub-annual and sub-national scales.
Amy McNally; Kristine Verdin; Laura Harrison; Augusto Getirana; Jossy Jacob; Shraddhanand Shukla; Kristi Arsenault; Christa Peters-Lidard; James P. Verdin. Acute Water-Scarcity Monitoring for Africa. Water 2019, 11, 1968 .
AMA StyleAmy McNally, Kristine Verdin, Laura Harrison, Augusto Getirana, Jossy Jacob, Shraddhanand Shukla, Kristi Arsenault, Christa Peters-Lidard, James P. Verdin. Acute Water-Scarcity Monitoring for Africa. Water. 2019; 11 (10):1968.
Chicago/Turabian StyleAmy McNally; Kristine Verdin; Laura Harrison; Augusto Getirana; Jossy Jacob; Shraddhanand Shukla; Kristi Arsenault; Christa Peters-Lidard; James P. Verdin. 2019. "Acute Water-Scarcity Monitoring for Africa." Water 11, no. 10: 1968.
In operational analyses of the surface moisture imbalance that defines drought, the supply aspect has generally been well characterized by precipitation; however, the same count be said of the demand side—a function of evaporative demand (E0) and surface moisture availability. In drought monitoring, E0 is often poorly parameterized by a climatological mean, by non-physically based estimates, or is neglected entirely. One problem has been a paucity of driver data—on temperature, humidity, solar radiation, and wind speed—required to fully characterize E0. This deficient E0 modeling is particularly troublesome over data-sparse regions that are also home to drought-vulnerable populations, such as across much of Africa. There is thus urgent need for global E0 estimates for physically accurate drought analyses and food security assessments; further we need an improved understanding of how E0 and drought interact and to exploit these interactions in drought monitoring. In this presentation we explore ways to meet these needs. From MERRA-2—an accurate, fine-resolution land-surface/atmosphere reanalysis—we have developed a >38-year, daily, global Penman-Monteith reference ET dataset as a fully physical metric of E0. This dataset is valuable for examining hydroclimatic changes and extremes. A novel drought index based on this dataset—the Evaporative Demand Drought Index (EDDI)—represents drought’s demand perspective, and permits early warning and ongoing monitoring of agricultural flash drought and hydrologic drought. We highlight the findings of our examination of E0-drought interactions and using EDDI in Africa. Using reference ET as an E0 metric has permitted explicit attribution of the variability of E0 across Africa, and of E0 anomalies associated with canonical droughts in the Sahel region. This analysis determines where, when, and to what relative degree each of the individual drivers of E0 affects the demand side of drought. Using independent estimates of drought across space and time—CHIRPS precipitation and the Normalized Difference Vegetation Index for 1982-2015—we examine the differences between drought and non-drought periods, and between precipitation-forced droughts and droughts forced by a combination of precipitation and E0.
Mike Hobbins; Laura Harrison; Sari Blakeley; Candida Dewes; Greg Husak; Shraddhanand Shukla; Harikishan Jayanthi; Amy McNally; Daniel Sarmiento; James Verdin. Drought in Africa: Understanding and Exploiting the Demand Perspective Using a New Evaporative Demand Reanalysis. 2019, 1 .
AMA StyleMike Hobbins, Laura Harrison, Sari Blakeley, Candida Dewes, Greg Husak, Shraddhanand Shukla, Harikishan Jayanthi, Amy McNally, Daniel Sarmiento, James Verdin. Drought in Africa: Understanding and Exploiting the Demand Perspective Using a New Evaporative Demand Reanalysis. . 2019; ():1.
Chicago/Turabian StyleMike Hobbins; Laura Harrison; Sari Blakeley; Candida Dewes; Greg Husak; Shraddhanand Shukla; Harikishan Jayanthi; Amy McNally; Daniel Sarmiento; James Verdin. 2019. "Drought in Africa: Understanding and Exploiting the Demand Perspective Using a New Evaporative Demand Reanalysis." , no. : 1.