Convective response to large-scale forcing in the tropical western Pacific simulated by spCAM5 and CanAM4.3

TitleConvective response to large-scale forcing in the tropical western Pacific simulated by spCAM5 and CanAM4.3
Publication TypeJournal Article
Year of Publication2019
AuthorsMitovski T., Cole J.NS, McFarlane N.A, von Salzen K., Zhang GJ
JournalGeoscientific Model Development
Volume12
Pagination2107-2117
Date Published2019/05
Type of ArticleArticle
ISBN Number1991-959X
Accession NumberWOS:000469432900002
Keywordscloud-resolving model; cumulus parameterization; events; Geology; mesoscale; precipitation; scheme; superparameterization; temperature; trigger functions; variability
Abstract

Changes in the large-scale environment during convective precipitation events in the tropical western Pacific simulated by version 4.3 of the Canadian Atmospheric Model (CanAM4.3) are compared against those simulated by version 5.0 of the super-parameterized Community Atmosphere Model (spCAM5). This is done by compositing sub-hourly output of convective rainfall, convective available potential energy (CAPE), CAPE generation due to large-scale forcing in the free troposphere (dCAPELSFT) and near-surface vertical velocity (omega) over the time period May-July 1997. Compared to spCAM5, CanAM4.3 tends to produce more frequent light convective precipitation (< 0.2 mm h(-1)) and underestimates the frequency of extreme convective precipitation (> 2 mm h(-1)). In spCAM5, 5% of convective precipitation events lasted less than 1.5 h and 75% lasted between 1.5 and 3.0 h, while in CanAM4.3 80% of the events lasted less than 1.5 h. Convective precipitation in spCAM5 is found to be a function of dCAPE(LSFT) and the large-scale near-surface omega with variations in omega slightly leading variations in convective precipitation. Convective precipitation in CanAM4.3 does not have the same dependency and instead is found to be a function of CAPE.

DOI10.5194/gmd-12-2107-2019
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