Seasonal variability of the temperature and salinity fields in the coastal zone of the states of Jalisco and Colima, Mexico

Abstract

The results of the analysis of data obtained from a series of oceanographic surveys conducted in an ecological monitoring polygon on the continental shelf off Jalisco and Colima (Mexico) are presented. The surveys were conducted monthly between 1995 and 1997 with an undulating CTD. In one day, up to 100 soundings were made at stations with a maximum depth of 150 m, in a spatial grid of points with an area of 50 · 15 km. The vertical profiles of temperature and salinity were obtained by averaging the data from the oceanographic surveys. It is shown that the vertical distributions and hydrophysical characteristics analyzed present a significant seasonal variability related to the annual variations of solar energy input and variability of evaporation, precipitation and coastal discharges in the study area. The seasonal oscillations cover a water layer greater than 100 m, but the subsurface layers of the coastal waters are observed with greater intensity. The mean profiles present a high statistical reliability, since the deformations caused by the internal waves were completely suppressed.