Water vapour adjustments and responses differ between climate drivers
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Published version
Author(s)
Type
Journal Article
Abstract
Water vapour in the atmosphere is the source of a major climate feedback mechanism and potential increases in the availability of water vapour could have important consequences for mean and extreme precipitation. Future precipitation changes further depend on how the hydrological cycle responds to different drivers of climate change, such as greenhouse gases and aerosols. Currently, neither the total anthropogenic influence on the hydrological cycle nor that from individual drivers is constrained sufficiently to make solid projections. We investigate how integrated water vapour (IWV) responds to different drivers of climate change. Results from 11 global climate models have been used, based on simulations where CO2, methane, solar irradiance, black carbon (BC), and sulfate have been perturbed separately. While the global-mean IWV is usually assumed to increase by ∼7 % per kelvin of surface temperature change, we find that the feedback response of IWV differs somewhat between drivers. Fast responses, which include the initial radiative effect and rapid adjustments to an external forcing, amplify these differences. The resulting net changes in IWV range from 6.4±0.9 % K−1 for sulfate to 9.8±2 % K−1 for BC. We further calculate the relationship between global changes in IWV and precipitation, which can be characterized by quantifying changes in atmospheric water vapour lifetime. Global climate models simulate a substantial increase in the lifetime, from 8.2±0.5 to 9.9±0.7 d between 1986–2005 and 2081–2100 under a high-emission scenario, and we discuss to what extent the water vapour lifetime provides additional information compared to analysis of IWV and precipitation separately. We conclude that water vapour lifetime changes are an important indicator of changes in precipitation patterns and that BC is particularly efficient in prolonging the mean time, and therefore likely the distance, between evaporation and precipitation.
Date Issued
2019-10-17
Date Acceptance
2019-09-02
Citation
Atmospheric Chemistry and Physics, 2019, 19 (20), pp.12887-12899
ISSN
1680-7316
Publisher
Copernicus Publications
Start Page
12887
End Page
12899
Journal / Book Title
Atmospheric Chemistry and Physics
Volume
19
Issue
20
Copyright Statement
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/).
the Creative Commons Attribution 4.0 License (https://creativecommons.org/licenses/by/4.0/).
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000491147900001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Life Sciences & Biomedicine
Physical Sciences
Environmental Sciences
Meteorology & Atmospheric Sciences
Environmental Sciences & Ecology
HYDROLOGICAL CYCLE
PRECIPITATION EXTREMES
LIFETIME
PDRMIP
Publication Status
Published
OA Location
https://www.atmos-chem-phys.net/19/12887/2019/acp-19-12887-2019.pdf
Date Publish Online
2019-10-17