Diurnal cycle of the Intertropical Convergence Zone in the east Pacific

TitleDiurnal cycle of the Intertropical Convergence Zone in the east Pacific
Publication TypeJournal Article
Year of Publication2010
AuthorsBain, C. L., Magnusdottir G., Smyth P., & Stern H.
JournalJournal of Geophysical Research-Atmospheres
Volume115
Date PublishedDec
Type of ArticleArticle
ISBN Number0148-0227
Accession Numberhttp://apps.isiknowledge.com/InboundService.do?Func=Frame&product=WOS&action=retrieve&SrcApp=EndNote&Init=Yes&SrcAuth=ResearchSoft&mode=FullRecord&UT=000285017500010
Keywords1000; clouds; Content Type: Biblio; convective activity; Magnusdottir Modeling Lab; ocean; precipitation; rainfall; satellite; scale; tropical pacific; variability; warm pool
Abstract

A data set of Intertropical Convergence Zone (ITCZ) extent and location in the eastern Pacific, 90 degrees W-180 degrees W, 0 degrees N-25 degrees N, is used to examine the diurnal cycle of cloudiness over the ocean. The data set was generated using a statistical model which utilizes 30 year, 3-hourly infrared (IR) satellite data from 1980 to 2009. The ITCZ envelope of convection has a significant diurnal cycle across the whole domain, and the area of cloudiness "pulses" in extent, peaking in the afternoon. The diurnal cycle of brightness temperatures within the ITCZ changes from east to west, but generally there are two minima in mean IR, implying cold cloud is at a peak: one in the morning, 0600-0900 LST, and another in the afternoon, 1300-1600 LST. Decomposition of cloud top temperatures show that high cloud is at a maximum in the early morning and midlevel cloud peaks in the afternoon. Low cloud is at a maximum in the late evening (2200-0000 LST) and is immediately followed by increases in high cloud, suggesting that the deepest convective systems grow rapidly, within a few hours overnight. There are seasonal changes in the diurnal cycle of cloud top temperature, and it is suggested that colder mean temperatures are more likely in the afternoon when the ITCZ is more extensive. This is shown via seasonal changes and also by comparing El Nino years, when ITCZ is more present, to La Nina years.

URLhttp://apps.isiknowledge.com/InboundService.do?Func=Frame&product=WOS&action=retrieve&SrcApp=EndNote&Init=Yes&SrcAuth=ResearchSoft&mode=FullRecord&UT=000285017500010
Alternate JournalJ. Geophys. Res.-Atmos.
ESS Associations
Research Area: 
Physical Climate
Research Lab: 
Magnusdottir Research Group