Evidence for added value of convection-permitting models for studying changes in extreme precipitation.

Meredith, Edmund, Maraun, Douglas, Semenov, Vladimir A. and Park, Wonsun (2015) Evidence for added value of convection-permitting models for studying changes in extreme precipitation. Open Access Journal of Geophysical Research - Atmospheres, 120 (24). pp. 12500-12513. DOI 10.1002/2015JD024238.

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Abstract

Climate model resolution can affect both the climate change signal and present-day representation of extreme precipitation. The need to parametrize convective processes raises questions about how well the response to warming of convective precipitation extremes is captured in such models. In particular, coastal precipitation extremes can be sensitive to sea surface temperature (SST) increase. Taking a recent coastal precipitation extreme as a showcase example, we explore the added value of convection-permitting models by comparing the response of the extreme precipitation to a wide range of SST forcings in an ensemble of regional climate model simulations using parametrized and explicit convection. Compared at the same spatial scale, we find that the increased local intensities of vertical motion and precipitation in the convection-permitting simulations play a crucial role in shaping a strongly nonlinear extreme precipitation response to SST increase, which is not evident when convection is parametrized. In the convection-permitting simulations, SST increase causes precipitation intensity to increase only until a threshold is reached, beyond which further SST increase does not enhance the precipitation. This flattened response results from an improved representation of convective downdrafts and near-surface cooling, which damp the further intensification of precipitation by stabilizing the lower troposphere locally and also create cold-pools that cause subsequent convection to be triggered at sea, rather than by the coastal orography. These features are not well represented in the parametrized convection simulations, resulting in precipitation intensity having a much more linear response to increasing SSTs

Document Type: Article
Additional Information: WOS:000369846700012
Keywords: added value; convection-permitting model; extreme precipitation; climate change; parametrized convection; storyline approach; nonlinear response
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-ME Maritime Meteorology
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2015JD024238
ISSN: 0148-0227
Projects: EUREX
Date Deposited: 16 Dec 2015 12:29
Last Modified: 11 Apr 2017 08:57
URI: http://oceanrep.geomar.de/id/eprint/30651

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