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

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 degrees C/yr. The seasonal maximum trend is associated to summer 0.070 +/- 0.001 degrees C/yr, followed by winter, (0.040 +/- 0.001) degrees C/yr, autumn 0.030 +/- 0.001 degrees C/yr and spring, 0.020 +/- 0.001 degrees C/yr. The total period analyzed has been divided into ten-year time spans, showing a stable increase of 0.055 degrees C/yr in average, from period 2005-2014 onwards. In absolute SST values terms, the parameter range is of 0.85 degrees 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 degrees C/yr for the Alboran Sea to 0.07 degrees 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. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Sea Surface Temperature (SST) trends in the Mediterranean Sea from 2003 to 2019 were estimated using MODIS Level 3 SST data, showing an overall warming trend of 0.055 degrees C/yr. Seasonal variations revealed a higher warming trend in summer and lower in spring. The analysis of SST spatial variability across nine sub-basins demonstrated different warming trends, with the Adriatic Sea showing the highest increase.