The annual surface temperature patterns across the Dead Sea as retrieved from thermal images

Abstract

Satellite images capture a large scene instantaneously, enabling direct comparisons of surface–atmosphere interactions in a static time domain. The annual course of surface temperature of the Dead Sea is investigated using thermal images obtained from Band 10 onboard Landsat 8. Retrieved sea surface temperature varied from around 20 °C in February to ~ 35 °C in July. Retrieved sea surface temperature is commensurate with extensive field measurements, with a root mean square error of 1.25 °C. Satellite images reveal three distinct thermal patterns. The first one is the presence of temperature variations across the open sea which may reflect differences in local meteorology and/or differential mixing with the deeper layers. The second feature is the different temperature skewness patterns between winter and summer months. A slight negative temperature skewness is observed during the period November through February, and a steep positive one during the rest of the year, with large values occurring during summer. These skewness patterns reflect the variations in the annual course of heating and cooling mechanisms occurring in the open sea and along the shallow shorelines. The third distinct feature is the presence of cold finger plumes during the cold months, extending around 4 km inside the open sea and covering an area in excess of 3 km2. The influence of freshwater flux on evaporation from large hypersaline water bodies is investigated using a theoretical formulation derived in this paper. Results show that the effect of freshwater flux on evaporation from hypersaline lakes is a complex process determined by activity and temperature departures. Satellite images provide an excellent surrogate to field observations which are money and labor intensive, time consuming, and very limited in their spatial coverage.