Drought in the Southeastern U.S. - future outlooks
Abstract
The Southeastern United States, a region used to abundant precipitation, has repeatedly been struck by droughts in the last decades. The droughts of 1986-1988, 1998-2002, 2006-2009 and 2016-2017 have caused significant environmental and economic losses, and sparked multiple lawsuits, including the "Tri-State Water Dispute" between the states of Alabama, Florida and Georgia. In this study future outlooks for extended dry spells in the Southeast are assessed. The study is divided into two parts, starting with an evaluation of the performance of 32 CMIP5 models' (downscaled using localized constructed analogs (LOCA)) capability of predicting historical dry spells (1950-2005) in the Southeastern United States. The data is divided into warm and cool seasons, based on timing of agricultural planting and harvesting dates of key crops. The models generally simulate the distribution of dry periods well, but there are large differences between the ability of the best and worst performing models, particularly when it comes to the upper tail of the distribution. Only the top models provide a good estimate of extreme dry spell lengths with simulations of 20 year return values within ± 5 days of observed values across the region. In the second step of the analysis the five best performing models for each season are used to make projections for the length of future (2020-2059 and 2060-2099) 20 year return period dry spells in the region, considering both the RCP 4.5 and RCP 8.5 emission scenarios. Based on the best models warm period droughts are likely to become shorter while the length of cold period droughts show more variability.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H41C..06E
- Keywords:
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- 1812 Drought;
- HYDROLOGYDE: 1817 Extreme events;
- HYDROLOGYDE: 1833 Hydroclimatology;
- HYDROLOGYDE: 1880 Water management;
- HYDROLOGY