Title: Dynamical and thermodynamical modulations on future changes of landfalling atmospheric rivers over western North America

Abstract

This study examines the changes of landfalling atmospheric rivers (ARs) over the west coast of North America in response to future warming using model outputs from the Coupled Model Intercomparison Project phase 5 (CMIP5). The result reveals a strikingly large magnitude of increase of AR days by the end of the 21st century in the RCP8.5 climate change scenario, with fractional increases ranging between ~50% and 600%, depending on the seasons and the landfall locations. These increases are predominantly controlled by the super-Clausius-Clapeyron rate of increase of atmospheric water vapor with warming, while changes of winds that transport moisture in the ARs, or dynamical effect, mostly counter the thermodynamical effect of increasing water vapor, limiting the increase of AR events in the future. Here, the consistent negative effect of wind changes on AR days during spring and fall can be further linked to the robust poleward shift of the subtropical jet in the North Pacific basin.

Authors:

Gao, Yang ^[1]; Lu, Jian ^[1]; Leung, L. Ruby ^[1]; Yang, Qing ^[1]; Hagos, Samson M. ^[1]; Qian, Yun ^[1]

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+ Show Author Affiliations

1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Publication Date:

Mon Aug 24 00:00:00 EDT 2015

Research Org.:

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1224503

Alternate Identifier(s):

OSTI ID: 1402358

Report Number(s):

PNNL-SA-110116
Journal ID: ISSN 0094-8276; KP1703010

Grant/Contract Number:  

AC05-76RL01830

Resource Type:

Accepted Manuscript

Journal Name:

Geophysical Research Letters

Additional Journal Information:

Journal Volume: 42; Journal Issue: 17; Journal ID: ISSN 0094-8276

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; atmospheric rivers; climate change; thermodynamic effects; dynamical effects; increased moisture