The level variability, thermal structure and currents in Lake Chapala, Mexico

Abstract

Measurements of temperature, currents and lake level taken in 2005-2014 are analyzed and discussed. Moored measurements of temperature and level in the northern part of the lake reveal the presence of seiches oscillations of the first and second modes, with periods of 5.7 and 2.8 hours, and amplitudes of 15.4 and 2.1 mm. In 2006 four temperature cross-sections were carried out in the study area. The obtained data reveal that in all four seasons of the year the temperatures averaged over the north and south coastal areas differ by 2-3°C. The lake currents were simulated using the HAMSOM 2-D hydrodynamic model both for wet and dry seasons. The model results are in good agreement with the ADCP data. The presence of an anticyclonic gyre, 10-12 km in diameter, in the central part of the lake in both seasons is revealed. In particular, the summer 2014 data provide evidence of the gyre and its impact on the spatial distribution of temperature in the lake.