Feedback mechanisms of shallow convective clouds in a warmer climate as demonstrated by changes in buoyancy

G. Dagan, I. Koren*, O. Altaratz, G. Feingold

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Cloud feedbacks could influence significantly the overall response of the climate system to global warming. Here we study the response of warm convective clouds to a uniform temperature change under constant relative humidity (RH) conditions. We show that an increase in temperature drives competing effects at the cloud scale: a reduction in the thermal buoyancy term and an increase in the humidity buoyancy term. Both effects are driven by the increased contrast in the water vapor content between the cloud and its environment, under warming with constant RH. The increase in the moisture content contrast between the cloud and its environment enhances the evaporation at the cloud margins, increases the entrainment, and acts to cool the cloud. Hence, there is a reduction in the thermal buoyancy term, despite the fact that theoretically this term should increase.

Original languageAmerican English
Article number054033
JournalEnvironmental Research Letters
Volume13
Issue number5
DOIs
StatePublished - May 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 The Author(s). Published by IOP Publishing Ltd.

Keywords

  • buoyancy
  • cloud feedback
  • shallow convection

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