Sea Surface Temperature changes analysis, an Essential Climate Variable for Ecosystem Services provisioning

Sea Surface Temperature is an Essential Climate Variable (ECV) that allows an effective quantitative estimation of recent changes in large marine ecosystem like the Mediterranean Sea. Sea Surface Temperature (SST) continues to rise, threatening marine ecosystem status and Ecosystem Services (ESS) provisioning. One of the questions that multitemporal analysis of Earth Observation (EO) time series should address is the response to variations in SST spatial distribution due to climate change. Ecosystem indicators like the fish growth rates across Mediterranean regions reveal temporal trends and regional variability. This study addresses the changes of the SST of the Mediterranean Sea "Large Marine Ecosystem" over the last three decades in order to evaluate trends, identify spatial and temporal patterns of SST variability from multitemporal analysis of EO products. Time series of daily SST estimated for the period 1982-2016 from multi-sensor satellite data were collected from operational Copernicus Marine Environment Monitoring Service (CMEMS). A wide range of statistical approaches are considered, like Seasonal Trend decomposition, Empirical Orthogonal Function, Self-Organizing Maps. Focusing on the thermal habitat of fish species, a fish growth model is used to reveal different scenarios in the potential growth of fish populations under past and current conditions as well as future climate projections. Results indicate that in the past three decades the eastern part of the Mediterranean Sea experienced greater SST increase than the western part, producing different scenarios of fish growth rates across the Mediterranean regions.