Evaluating Surface Radiation Fluxes Observed From Satellites in the Southeastern Pacific Ocean

This study is focused on evaluation of current satellite and reanalysis estimates of surface radiative fluxes in a climatically important region. It uses unique observations from the STRATUS Ocean Reference Station buoy in a region of persistent marine stratus clouds 1,500km off northern Chile during 2000-2012. The study shows that current satellite estimates are in better agreement with buoy observations than model outputs at a daily time scale and that satellite data depict well the observed annual cycle in both shortwave and longwave surface radiative fluxes. Also, buoy and satellite estimates do not show any significant trend over the period of overlap or any interannual variability. This verifies the stability and reliability of the satellite data and should make them useful to examine El Nino-Southern Oscillation variability influences on surface radiative fluxes at the STRATUS site for longer periods for which satellite record is available. Plain Language Summary The ability of satellites to provide accurate estimates of shortwave and longwave radiation reaching the surface of the ocean is investigated by comparing satellite estimates with observations from a surface buoy. The buoy was deployed since 2000 at a site 1,500km off northern Chile, where persistent clouds complicate remote sensing of the ocean surface. Good agreement has been found between current satellite products and the buoy; the results are better than those found with surface radiation estimates based on reanalysis models. Since the satellite data capture well the annual cycle in radiative fluxes at the buoy, and there are no detectable trends in buoy and satellite shortwave and longwave radiation, the satellite data are seen to have good temporal stability. Neither satellite nor the buoy showed interannual variability in surface radiative fluxes at the site; using satellite data to map where El Nino-Southern Oscillation variability is seen shows that the STRATUS site is just south of the region where El Nino-Southern Oscillation variability is seen in surface radiative fluxes.