Low-level flow around the Baja California peninsula during NAME

This study presents an analysis of ten NOAA P-3 missions carried out during NAME-2004. We focus on the structure of the low-level flow over and around the Baja California peninsula. The aircraft flew a pattern of descending and ascending legs that yielded detailed cross-sections of the marine boundary layer structure over the eastern Pacific to the west of the Baja California peninsula and over the Gulf of California to the east. The observations reveal interesting coastal and orographic effects including i) a barrier jet to the west of Baja California, ii) relatively drier low-level Pacific flow entraining into the Gulf of California, and iii) major moisture flux spatial variability over the Gulf of California. Understanding these low-level flow features is important for evaluating fine-resolution regional climate simulations and analysis products, some of which are also presented. Some comparisons of the observations with simulations show both the ability and inability of these simulations to reproduce the observed features. The implications for overall simulations of the monsoonal flow are discussed.