Spatial and seasonal variability of temperature, salinity and density in Bahía Concepción, Gulf of California, Mexico

This study analyzed the seasonal and spatial (longitudinal, transverse and depth) variability of temperature, salinity, and density in the Bahía Concepción in the Gulf of California, Mexico. CTD data from 4 oceanographic cruises carried out during 1994 (winter, spring, summer, and autumn) were used. The presence of wind-driven southeast upwelling at the mouth of the Bahía de Concepción was found during stratified and warm conditions in the spring and summer of 1994, with the highest index of wind-induced upwelling and the maximum frequency of Brunt-Väisälä in spring. The Bay was stratified and warm in temperature during spring and summer with the thermocline, halocline, and pycnocline more pronounced in spring. This was mainly due to increased solar radiation and the arrival of cold and less salty water from the Gulf of California, caused by upwelling on the west coast of the gulf generated by the winds from the southeast. Meanwhile in autumn and winter the Bahía Concepción showed homogeneous and cold conditions, produced by strong northwest winds and lower solar radiation. The distribution of temperature, salinity, and density varied seasonally and spatially due to solar radiation, warm stratification, upwelling, and wind-driven flow. Conditions in the Bay ranged from homogeneous and cold to stratified and warm, apparently separated by two short transition periods.