Regional-scale model climatology of the North American monsoon system

Details Regional-scale model climatology of the North American monsoon system Regional-scale model climatology of the North American monsoon system

Jul 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998phdt.......105s&link_type=abstract

Thesis (PhD). THE UNIVERSITY OF UTAH, Source DAI-B 59/08, p. 4182, Feb 1999, 159 pages.

Computer Science

Scientific paper

The regional climate of the North American monsoon system over the eastern equatorial Pacific Ocean and adjacent land areas is simulated during June, July, and August 1990-1997. The Pennsylvania State University/National Center of Atmospheric Research Mesoscale Model 5 (MM5) is forced by the observed evolution of sea surface temperature and the National Center for Environmental Prediction (NCEP) reanalyses of the atmospheric flow on the lateral boundaries. The MM5 reproduces many of the general features of the large-scale circulation found in the NCEP reanalyses. It does, however, develop a stronger regional meridional circulation with higher precipitation rates in the Intertropical Convergence Zone (ITCZ), stronger cross- equatorial flow in the boundary layer, and greater divergent flow aloft. The model ITCZ is displaced too far north and tends to be located over the highest sea surface temperature. Mesoscale circulation features, such as diurnal land/sea breezes and gap flows across Mexico and Central America, are captured. The observed latitudinal transition from the shallow planetary boundary layer (PBL) with stratiform clouds over the cool waters of the equatorial Pacific to a relatively deeper PBL further north is simulated by the model. More tropical cyclones develop in the MM5 than were observed and they were comparatively shorter-lived and weaker. Also, the model, as presently configured, does not realistically simulate the year-to-year variations in tropical cyclones. The regional circulation during Summer 1997 was dominated by the planetary-scale El Ni/tilde no/Southern Oscillation phenomenon. The normally cool waters along the equator were unusually warm with enhanced convection to the south of the mean position of the ITCZ. Large- scale subsidence over Central America and the extreme eastern Pacific Ocean led to drought conditions in that region. The number and intensity of tropical cyclones observed during summer 1997 in the eastern equatorial Pacific were reduced despite the fact that the most intense hurricane of the eight seasons occurred during that year. The MM5 captures the weaker and broader ITCZ during summer 1997 over the eastern equatorial Pacific.

Affiliated with

Also associated with

No associations

Rating

Regional-scale model climatology of the North American monsoon system does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Regional-scale model climatology of the North American monsoon system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Regional-scale model climatology of the North American monsoon system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1271919