Temporal trends in sea surface temperature gradients in the South Atlantic Ocean

In this study, we investigate the spatial and temporal characteristics of Sea Surface Temperature (SST) gradients in the South Atlantic Ocean (SAO) using satellite data. 12 years (2003-2014) of high resolution synoptic SST images acquired from NASA's MODIS instrument onboard Terra and Aqua platforms were processed to mitigate quality issues related to stripe noise and cloud misclassification and then compiled into monthly, yearly, and decadal maps of SST gradient magnitudes. We used these composite maps and corresponding time series to identify regions with strong frontal activity and characterize the seasonal and long term evolution of thermal gradients. While a clear seasonal cycle was observed in most subregions of the SAO, the satellite data do not suggest significant interannual variability or long term changes in the magnitude of thermal fronts in the SAO except in the upwelling region of Cape Frio Brazil, where SST gradients have increased at an approximate rate of 1% per year since 2003.