Effect of hydroclimatological teleconnections on the watershed‐scale drought predictability in the southeastern United States

• Published in: International journal of climatology Vol. 38; no. S1; pp. e1139 - e1157
• Main Authors: Sehgal, Vinit, Sridhar, Venkataramana
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.04.2018; Wiley Subscription Services, Inc
• Subjects: Atmospheric circulation; Atmospheric circulation patterns; Atmospheric models; Circulation patterns; Climate; Climatic conditions; Climatic indexes; Computer simulation; Correlation; Correlation analysis; Drought; Drought index; drought predictability; Dynamics; ENSO; Environmental assessment; Evapotranspiration; hydroclimatology; Hydrologic models; Hydrology; Moisture content; PDSI; Potential evapotranspiration; Precipitation; Rainfall; Seasonal variations; Seasonality; Soil; Soil moisture; Soil water; Soil water storage; southeastern United States; SWAT; Teleconnections; Water balance; Water balance components; Water storage; Watershed hydrology; Watersheds; United States > US
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.5439

ABSTRACT Large‐scale atmospheric circulation patterns have a strong influence on hydrologic variability in the southeastern United States (SEUS). These climatic indices are often linked with anomalous climatic conditions and thus can be useful to forecast either water surplus or deficit conditions over the region. This study provides an assessment of the watershed‐scale influence of hydroclimatological teleconnections in the context of drought predictability. The interrelationship between several climate indices is assessed with the monthly percentiles of soil water storage (SW), precipitation (PCP), surface run‐off (SURQ), and potential evapotranspiration (PET) for 50 watersheds in the South Atlantic Gulf region of the SEUS. The hydrologic variables are simulated by implementing SWAT models for each watershed at a HUC‐12 resolution for a period of January 1982 through December 2013. The study highlights the strong correlation between the climate indices and watershed‐scale hydrologic variables and provides important insights on the effect of seasonality and the dynamics of water balance components on the predictability of drought at watershed‐scale. Among all hydrologic variables evaluated, soil moisture shows a stronger relationship with the climate indices compared to PCP, SW, and SURQ. The interrelationship between watershed hydrology and climate indices is found to be stronger during fall (September–November) and winter seasons (December–February) with high correlation of SW and PCP with the climate indices, especially in the Carolinas, Georgia, and parts of Florida. Simulated SW corresponds strongly with the Palmer drought severity index (PDSI) in terms of its response to climate indices, indicating that SW can be an effective predictor of drought in the region. Graphical summary of the watershed scale drought predictability analysis for the Southeastern US.