Surface Temperature trends in the Mediterranean Sea from MODIS data during years 2003–2019

Abstract

Sea Surface Temperature is a variable recognized as an Essential Climate Variable (ECV) by the Global Climate Observation System (GCOS), due to its determinant influence on climate dynamics, from micro scale to global levels The aim of this paper is to estimate Sea Surface Temperature trends in the Mediterranean Sea during years 2003–2019 by using the MODIS Level 3 SST Thermal IR 8 Day 4km V2019.0. Results show an SST increase of 0.040 ± 0.001 °C/yr. The seasonal maximum trend is associated to summer 0.070 ± 0.001 °C/yr, followed by winter, (0.040 ± 0.001) °C/yr, autumn 0.030 ± 0.001 °C/yr and spring, 0.020 ± 0.001 °C/yr. The total period analyzed has been divided into ten-year time spans, showing a stable increase of 0.055 °C/yr in average, from period 2005–2014 onwards. In absolute SST values terms, the parameter range is of 0.85°C from year 2005 to 2019. We have also analyzed the spatial variability of the parameter by dividing the Mediterranean Sea into nine sub-basins: Alboran Sea, Balearic Sea (Iberian Sea), Mediterranean Western Basin, Mediterranean Eastern Basin, Ligurian Sea, Tyrrhenian Sea, Ionian Sea, Adriatic Sea and Aegean Sea. The results show warming trends from 0.02 °C/yr for the Alboran Sea to 0.07°C/yr for the Adriatic Sea. Results have been validated by using data from a local observational buoy system, obtaining a coefficient of determination of 0.97.