Spatio-Temporal Analysis of Water Surface Temperature in a Reservoir and its Relation with Water Quality in a Climate Change Context.

Remote sensing community is making enormous efforts to implement early warning systems capable for following spatio-temporal patterns of water quality and climate change risk indicators, being Horizon 2030 EOXPOSURE project one of them. This work presents first results of surface temperature Landsat 8 Level 2 Collection 2 products analysis for a reservoir and compare them with field data measurements. A Root Mean Square Error (RMSE) of 1.7$^o$C and a Mean Absolute Percentage Error (MAPE) of 7\% were obtained for these products but validation curve resulted not confident at a 95\% level. A semiempirical linear model with 94\% accuracy, RMSE of 1.1$^o$C and a MAPE of 5\% is presented. It was successfully validated with a control group data set obtaining 94\% accuracy. A Water Surface Temperature temporal series is shown for the 2013-2020 period and spatio temporal patterns are analyzed and discussed. Water surface temperature behavior in zones with algal bloom occurrence present greater significant values, up to 3$^o$C, than those with clearer water, indicating that water emissitiviy must be revised for these cases