Relationships between Sea Surface Temperatures in the Gulf of California and Surge Events

Abstract

Relationships between sea surface temperatures (SSTs) in the Gulf of California (GoC) and moisture surge events during the North American Monsoon Experiment (NAME) were examined using the multiplatform-merged daily SST data and the final NCEP North American Regional Reanalysis.When tropical storms pass through the southern end of the gulf, they often trigger moisture surge events. When surge events pass through the gulf, SSTs in the GoC decrease. Evidence indicates that changes in SSTs in the GoC are caused by the surge events associated with tropical storms.The intensification of surface winds and changes in humidity and temperature near the surface associated with surge events increase evaporation and decrease the latent heat entering the gulf. Rainfall originating from the peaks and foothills of the Sierra Madre Occidental (SMO) propagates westward into the GoC. Cloudiness increases over the GoC during the surge events, preventing shortwave radiation from reaching the oceanic surface. The net radiation entering the ocean reduces, and less heat into the ocean leads to the cooling of SSTs in the gulf.

An anomaly in the occurrence of the month of maximum precipitation distribution in northwest Mexico

“…The maximum seasonal thermal state of East Pacific warm pool occurs from July to September and has been considered to provide significant moisture for NAM rainfall (Cavazos et al, 2008;Mo and Higgins, 2008). This area is characterized by high SSTs between July and October with an average SST greater than 28.5 C (Wang and Enfield, 2003) and salinities above 34.9 psu with lower temperature and salinity values in the surrounding water .…”