Precipitation sensitivity to local variations in tropical sea surface temperature

Jie He, Nathaniel C. Johnson, Gabriel A. Vecchi, Benjamin Kirtman, Andrew T. Wittenberg, Stephan Sturm

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

The driving of tropical precipitation by the variability of the underlying sea surface temperature (SST) plays a critical role in the atmospheric general circulation. To assess the precipitation sensitivity to SST variability, it is necessary to observe and understand the relationship between precipitation and SST. However, the precipitation-SST relationships from any coupled atmosphere-ocean system can be difficult to interpret given the challenge of disentangling the SST-forced atmospheric response and the atmospheric intrinsic variability. This study demonstrates that the two components can be isolated using uncoupled atmosphere-only simulations, which extract the former when driven by time-varying SSTs and the latter when driven by climatological SSTs. With a simple framework that linearly combines the two types of uncoupled simulations, the coupled precipitation-SST relationships are successfully reproduced. Such a framework can be a useful tool for quantitatively diagnosing tropical air-sea interactions. The precipitation sensitivity to SST variability is investigated with the use of uncoupled simulations with prescribed SST anomalies, where the influence of atmospheric intrinsic variability on SST is deactivated. Through a focus on local precipitation-SST relationships, the precipitation sensitivity to local SST variability is determined to be predominantly controlled by the local background SST. In addition, the strength of the precipitation response increases monotonically with the local background SST, with a very sharp growth at high SSTs. These findings are supported by basic principles of moist static stability, from which a simple formula for precipitation sensitivity to local SST variability is derived.

Original languageEnglish (US)
Pages (from-to)9225-9238
Number of pages14
JournalJournal of Climate
Volume31
Issue number22
DOIs
StatePublished - Nov 1 2018

Keywords

  • Atmosphere-ocean interaction
  • Convection
  • Coupled models
  • Precipitation
  • Sea surface temperature
  • Tropical variability

ASJC Scopus subject areas

  • Atmospheric Science

Fingerprint Dive into the research topics of 'Precipitation sensitivity to local variations in tropical sea surface temperature'. Together they form a unique fingerprint.

  • Cite this