The Role of Water Vapour in Earth’s Energy Flows

Authors: Richard P Allan

Publish Date: 2011/11/24

Volume: 33, Issue: 3-4, Pages: 557-564

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Abstract

Water vapour modulates energy flows in Earths climate system through transfer of latent heat by evaporation and condensation and by modifying the flows of radiative energy both in the longwave and shortwave portions of the electromagnetic spectrum This article summarizes the role of water vapour in Earths energy flows with particular emphasis on 1 the powerful thermodynamic constraint of the Clausius Clapeyron equation 2 dynamical controls on humidity above the boundary layer or freetroposphere 3 uncertainty in continuum absorption in the relatively transparent window regions of the radiative spectrum and 4 implications for changes in the atmospheric hydrological cycleThanks to Paul O’Gorman Remy Roca Keith Shine Brian Soden and two anonymous reviewers for comments and corrections on the original manuscript and for their input along with BJ Sohn Andrew Dessler and many others to the International Space Sciences Institute Workshop Session on Observing and modelling Earth’s energy flows R Allan was supported by the UK Natural Environment Research Council PREPARE project NE/G015708/1

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