Thermal structure and circulation in Lake Chapala, Mexico

This study analyzed and discussed the instrumental measurements of temperature and currents made on January 10, 2007, in Lake Chapala. We received new data on the formation of the thermocline. It is shown that the thermocline of the lake is formed only in the daytime and in a top-heated 0.5-1.0 m layer. The vertical temperature gradient reaches 2.5°C in the first meter, and the spatial average temperature across the lake showed that the northern end of the lake is, on average, 1°C warmer than the southern end. We numerically modelled the currents in the lake for the dry season using the HAMSOM 2D hydrodynamic model. The simulation results are in good agreement with the acoustic Doppler current profiler ADCP measurements. In the dry season, two gyres were found: a cyclonic gyre in the eastern part and an anticyclonic gyre in the western part.