Title: Microphysical Sensitivity of Superparameterized Precipitation Extremes in the Contiguous United States Due to Feedbacks on Large-Scale Circulation

Abstract

Superparameterized (SP) global climate models have been shown to better simulate various features of precipitation relative to conventional models, including its diurnal cycle as well as its extremes. While various studies have focused on the effect of differing microphysics parameterizations on precipitation within limited-area cloud-resolving models, we examine here the effect on contiguous U.S. (CONUS) extremes in a global SP model. We vary the number of predicted moments for hydrometeor distributions, the character of the rimed ice species, and the representation of raindrop self-collection and breakup. Using a likelihood ratio test and accounting for the effects of multiple hypothesis testing, we find that there are some regional differences, particularly during spring and summer in the Southwest and the Midwest, in both the current climate and a warmer climate with uniformly increased sea surface temperatures. These differences are most statistically significant and widespread when the number of moments is changed. To determine whether these results are due to (fast) local effects of the different microphysics or the (slower) ensuing feedback on the large-scale atmospheric circulation, we run a series of short, 5-day simulations initialized from reanalysis data. We find that the differences largely disappear in these runs and therefore infer that themore » different parameterizations impact precipitation extremes indirectly via the large-scale circulation. Finally, we compare the present-day results with hourly rain gauge data and find that SP underestimates extremes relative to observations regardless of which microphysics scheme is used given a fixed model configuration and resolution.« less

Authors:

Charn, Alexander B.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-0076-8357"

Collins, William D.  ^[1];

• Search DOE PAGES for author "Collins, William D."
• Search DOE PAGES for ORCID "0000-0002-4463-9848"

Parishani, Hossein  ^[2];

• Search DOE PAGES for author "Parishani, Hossein"
• Search DOE PAGES for ORCID "0000-0002-4454-3184"

Risser, Mark D.  ^[3];

• Search DOE PAGES for author "Risser, Mark D."
• Search DOE PAGES for ORCID "0000-0003-1956-1783"

O'Brien, Travis A.  ^[4]

• Search DOE PAGES for author "O'Brien, Travis A."
• Search DOE PAGES for ORCID "0000-0002-6643-1175"

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2. Univ. of California, Irvine, CA (United States)
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
4. Indiana Univ., Bloomington, IN (United States)

Publication Date:

Sat Apr 04 00:00:00 EDT 2020

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1756333

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Earth and Space Science

Additional Journal Information:

Journal Volume: 7; Journal Issue: 7; Journal ID: ISSN 2333-5084

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; extreme precipitation; superparameterization; microphysics; Community Atmosphere Model; ILIAD; Climate Prediction Center Hourly Precipitation Dataset