An observational analysis of the relationship between variability in sea surface temperature gradients and the atmospheric circulation near the Kuroshio-Oyashio extension

The advent of increasingly high-resolution satellite observations and numerical models has led to a series of advances in our understanding of the role of sea surface temperature (SST) gradients in climate variability, especially near western boundary currents. For example, recent observational analyses suggest that ocean dynamics play a central role in driving interannual SST variability over the Kuroshio-Oyashio extension region, and recent numerical experiments suggest that variations in the SST field in the Kuroshio-Oyashio extension region have a much more pronounced influence on the atmospheric circulation than previously thought. In this talk we will assess the observational support for (or against) a robust atmospheric response to mid-latitude ocean variability in the Kuroshio-Oyashio extension region. We investigate in detail the relationships between variability in SST gradients over the Kuroshio-Oyashio extension region and various key atmospheric parameters, including the amplitude of baroclinic waves, precipitation, and the near-surface flow. The results provide an observational basis for interpreting climate simulations of the atmospheric response to variations in SST gradients in the North Pacific sector.