Influence of lake morphology and clarity on water surface temperature as measured by EOS ASTER

Relationships between lake morphometric parameters and nighttime lake surface temperatures were investigated in North American temperate lakes using the ASTER kinetic temperature (AST08) product. Nighttime ASTER kinetic temperature measurements were found to be a good analogue for nighttime surface temperatures. Linear regression between ASTER and buoy-measured temperatures in a test lake were better during the evening (R² = 0.98) than the day (R² = 0.90), presumably due to the greater influence of radiation and latent heat fluxes during daylight hours. Nighttime lake surface temperatures measured in three ASTER scenes were significantly correlated to logarithm of lake area, maximum lake depth, Secchi depth (a measure of lake clarity) and lake order (a measure of lake connection with surface drainage), during October and November. Nighttime lake surface temperatures were significantly correlated only with lake area in July. We hypothesize that morphology was more strongly related to surface temperature in the fall months due to lake turnover during that season. This study suggests that satellite derived thermal data may be useful for calculation of lake heat budgets and evaporation rates, provided surface temperatures are measured in well-mixed lakes.