Lower Tropospheric Analysis of the Daily Cycle of the Wind for the East Coast of the Gulf of California during NAME 2004

The daily cycle of the wind in the lower troposphere is not well known over the Gulf of California and the western coastal plains of Mexico. During the North American Monsoon (NAM) it is thought to be associated with the daily cycle of convective precipitation in this region. Half-hourly lower tropospheric winds from three wind profilers have been analyzed. These wind profilers were deployed along the coastal plain of Mexico during the Enhanced Observation Period (EOP) of the North American Monsoon Experiment (NAME 2004). The data from the wind profilers were used to document and understand the daily cycle profile of the winds during the monsoon. Mean profiles and mean daily cycles were computed at Puerto Peñasco (31.34ºN, 113.51ºW), Bahía Kino (28.81ºN, 111.93ºW), and Los Mochis (25.69ºN, 109.08ºW) over the first half of the 2004 NAM. The mean profiles show shallow southerly winds backing to easterlies; the southerlies deepen with latitude. The mean daily cycles show land/sea breezes at the most southern sites and a low level jet at the northern site. The directional constancy of these features is high. These results give an initial look into the structure of the winds in the lower atmosphere in this area and their variability along the Gulf of California, which have not been previously documented. This work has raised additional questions about the wind flow in this region that may facilitate future research of the NAM and will be useful for the improvement of models forecasting this phenomenon.