Spatial and temporal surface temperature patterns across the Dead Sea as investigated from thermal images and thermodynamic concepts

Abstract

The annual cycle of the Dead Sea surface temperature was investigated using band 10 onboard Landsat 8 during 2017–2018 and thermodynamic concepts. Retrieved Dead Sea temperatures are congruent with field observations with a mean square error of 1.22 °C and a correlation coefficient of 0.983. A new method employing thermodynamic concepts is presented in this paper to address the influence of buoyant plumes generated by freshwater influx on evaporation from hypersaline lakes/lagoons. Thermal images reveal a distinct spatial temperature pattern across the Dead Sea which reflects differential heating and cooling caused by variations in thermophysical characteristics of the deep sea compared with the shallow shoreline. The temperature patterns are negatively skewed in winter and positively skewed in summer. These temporal and spatial temperature patterns were illustrated using observed hourly data combined with energy balance calculations. The presence of buoyant plumes is found to alter evaporation compared with the undisturbed sea brine, and the effect of these plumes on evaporation is controlled by the simultaneous departure of temperature and activity compared with the undisturbed sea brine. Analysis shows that evaporation from buoyant plumes is more likely to be smaller than that from the open sea in winter and larger than its corresponding part from the open sea in summer. Thermal images can be used as surrogates to intensive field campaigns to examine temperature and evaporation regimes of lakes/salt flats.