Premium
Projected Changes in Summertime Circulation Patterns Imply Increased Drought Risk for the South‐Central United States
Author(s) -
Ryu JungHee,
Hayhoe Katharine,
Kang SongLak
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl080593
Subject(s) - climatology , ridge , environmental science , atmosphere (unit) , sea surface temperature , climate model , zonal and meridional , coupled model intercomparison project , oceanography , global warming , climate change , atmospheric sciences , geology , geography , meteorology , paleontology
Historically, extreme hot, dry summers over the South‐Central (SC) United States are dominated by an isolated dome of high pressure centered over the region. Applying self‐organizing map techniques to North American Regional Reanalysis reanalysis and historical and future Coupled Model Intercomparison Project version 5 (CMIP5) simulations, we find that as the world warms, this type of high‐pressure system is likely to become stronger and more frequent—even after removing the effect of surface warming on the expansion of the lower atmosphere. These projected changes appear to be related to self‐reinforcing ocean‐atmosphere interactions in a warming world. Specifically, intensified easterly winds over the Atlantic and Gulf of Mexico drive an increase in the meridional sea surface temperature gradient due to oceanic Ekman transport, which further enhances the ridge of high pressure extending across the SC United States: a dynamical relationship that increases confidence in regional projections of summer drought risk over the SC United States.