Hydroclimatology of the Southeastern USA

Abstract

We provide an overview of the hydroclimatology of the Southeastern USA, and review the primary factors that influence hydroclimatic variability on seasonal to interannual timescales. The Southeastern USA is characterized by high mean annual precipitation, but with significant variability. Precipitation variability is on the rise in this region, with more frequent, longer duration dry periods and infrequent, short duration, but heavy precipitation events. Hydroclimatic extremes are a relatively common occurrence in the region. Seasonal to interannual hydroclimatic variability in the Southeast is primarily controlled by El Niño/Southern Oscillation (ENSO), the Pacific North American (PNA) pattern, the Bermuda High, and tropical cyclones. Future research should focus on providing a better understanding of current and future drivers of hydroclimatic variability, including interactions between human-dominated components, such as urban areas, and the hydroclimatic system. Additional research is also needed on hydroclimatic extremes (droughts and floods).

Warm Season Hydroclimatic Variability and Change in the Appalachian Region of the Southeastern U.S. from 1950 to 2018

“…Additionally, teleconnection patterns likely influence hydroclimatic trends differently in the SAM than in the SEUS due to the added influence of topographic variability and its interaction with the low level moisture flux from the surface to the middle troposphere. Very few stations have significant correlations between these teleconnection patterns and heavy precipitation variability, whereas these teleconnection patterns are known to have a marked influence of hydroclimatic variability in the SEUS [13,17,[20][21][22][23].…”

“…Topographic and geographic features, such as slope, aspect, elevation, and exposure are known to play critical roles in the spatial distribution of precipitation events, thus adding regional differences within the SEUS [7,8]. The hydroclimate of the SEUS is changing, with increased precipitation variability and dry spells [2,6,[11][12][13][14]. Many changes have occurred during the warm season.…”

“…Among those researching the drivers of the SEUS's hydroclimate, some identified a link between sea surface temperatures and various climate indices and circulation patterns [13,17,[20][21][22][23][24]. Much research has also examined the synoptic-scale circulation patterns that are associated with anomalous warm season precipitation totals [16,17,20].…”

“…In general, wet periods across the southeast are tied to the eastward displacement of the North Atlantic Subtropical High, while dry periods are tied to its westward displacement. This suggests that the Pacific North American Index (PNA) and the Bermuda High Index (BHI) are drivers of hydroclimatic variability in the SEUS [13,[25][26][27].…”

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

“…Hydrologic variability in the SEUS in terms of precipitation and streamflow can be partly explained by the phase of various hydroclimatological teleconnections (Kahya and Dracup, 1993;Labosier and Quiring, 2013;Engström and Waylen, 2017a). Previously, Labosier and Quiring (2013) reviewed the hydroclimatology of the e1140 V. SEHGAL AND V. SRIDHAR SEUS and concluded that the region is strongly impacted by El Niño-Southern Oscillation (ENSO), the Pacific North American (PNA) pattern, the Bermuda High, and tropical cyclones. ENSO, the North Atlantic Oscillation (NAO), and PNA pattern all found to significantly change seasonal precipitation and run-off in the SEUS (Engström and Waylen, 2017a).…”