Influence of internal variability and global warming on multidecadal changes in regional drought severity over the continental United States

Tushar Apurv, Ximing Cai, Xing Yuan

Research output: Contribution to journalArticle

Abstract

Meteorological droughts in the continental United States (CONUS) are known to oscillate at the multidecadal time scale in response to the sea surface temperatures (SST) variability over the Pacific Ocean and the North Atlantic Ocean. While previous studies have focused on understanding the influence of SST oscillations on drought frequency over the CONUS, this information has not been integrated with global warming for future drought risk assessment at the decadal scale. In this study, we use the support vector machines (SVMs) to handle correlation between input variables for quantifying the influence of internal variability [Atlantic multidecadal oscillation (AMO) and Pacific decadal oscillation (PDO)] and global warming on the decadal changes in the severity of seasonal droughts over the CONUS during 1901-2015. The regional drivers of drought severity identified using SVMs are used for the assessment of decadal drought risk in the near future. We find internal variability as the dominant driver of decadal changes in drought severity in the southern and central Great Plains and global warming as the dominant driver for the southeastern and southwestern United States. In the southern Plains, the existing pattern of increasing drought severity is likely to persist in the near future if AMO and PDO remain in their positive and negative phases, respectively, while global warming is likely to contribute to increasing drought severity in the Southeast and Southwest. This study suggests an emerging role of global warming in drought risk over the southern states, where near-term climate change adaptation is necessary.

Original languageEnglish (US)
Pages (from-to)411-429
Number of pages19
JournalJournal of Hydrometeorology
Volume20
Issue number3
DOIs
StatePublished - Mar 1 2019

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global warming
drought
Atlantic Multidecadal Oscillation
Pacific Decadal Oscillation
sea surface temperature
risk assessment
oscillation
timescale
ocean

Keywords

  • Climate change
  • Drought
  • Multidecadal variability
  • Sea surface temperature

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Influence of internal variability and global warming on multidecadal changes in regional drought severity over the continental United States. / Apurv, Tushar; Cai, Ximing; Yuan, Xing.

In: Journal of Hydrometeorology, Vol. 20, No. 3, 01.03.2019, p. 411-429.

Research output: Contribution to journalArticle

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