Differences in coastal and oceanic SST warming rates along the Canary upwelling ecosystem from 1982 to 2010

Sea surface temperature (SST) trends were calculated for the Moroccan part (22–33 °N) of the Canary upwelling ecosystem, which is characterized by permanent upwelling. This analysis was carried out from 1982 to 2010 by means of daily SST data with an approximate spatial resolution of 4×4 km.SST trends are not homogeneous either in latitude or longitude. SST trends were observed to increase southward, which can be explained in terms of air temperature (Tair) trends that follow a similar pattern. In addition, remarkable differences in warming trends were observed between coastal and ocean locations at the same latitude (ΔSSTtrend=SSToceantrend−SSTcoasttrend). ΔSSTtrend is positive at most of latitudes showing that the ocean warming rate is higher than the coastal one. The differences between coast and ocean were observed to depend on upwelling index (UI) intensity. Actually, UI calculated for the months with intense upwelling (May–September) showed a no significant positive trend and was significantly correlated (R=0.44; p<0.05) with ΔSST averaged from August to December. In addition, the extended winter EA (December–March) showed a significant correlation (R=0.57; p<0.01) with ΔSST for the months of highest upwelling intensity when a lag of 1 yr was considered between both variables.

► We analyze SST changes along the Canary Upwelling System (CUE).
► Different warming rates can be observed at coastal and ocean locations.
► The different warming rates are related to changes in upwelling intensity.
► EA teleconnection patterns are also correlated with differences in SST.