Fundamental to an understanding of El Nino/Southern Oscillation climate fluctuations is an understanding of the interannual equatorial Pacific surface flows which advect the surface waters and change the sea surface temperature. Through the advent of accurate satellite altimeter measurements from late 1992 to the present, we now have long records of estimated sea levels and surface currents that are spatially well resolved and available not just in the Pacific, but also in the Indian and Atlantic Oceans. These records are long enough to study the observed interannual surface flows and their dynamics. While we have some knowledge of the observed interannual flows in the equatorial Pacific, less is known about the structure, strength and variability of the interannual flows in the equatorial Indian and Atlantic Oceans. The main goal of the project will be to describe the interannual equatorial surface flows in all three ocean basins and understand major aspects of them using theory and the dynamically consistent high resolution ECCO2 numerical model results. The scientific community is beginning to take advantage of the ECCO2 global ocean model, and a secondary benefit of the analysis will be the evaluation of the accuracy of this model and its dynamics near the equator in all three ocean basins.
Broader Impacts: Accurate, long satellite altimeter records from 1992 to the present day provide an unprecedented opportunity to examine the detailed spatial and time-varying structure of low frequency surface equatorial flows, flows which play a key role in changing equatorial sea surface temperature and climate. As noted above, surprisingly little is known about the structure and dynamics of these flows, so investigating these flows, and understanding their physics in all three equatorial ocean basins, will make a significant impact on our knowledge of equatorial ocean and climate dynamics. This fundational knowledge will be helpful to the many scientists who will analyze future long records of equatorial climate data gathered in the multinational Atlantic Ocean PIRATA and Indian Ocean RAMA observational programs. It is important to the future of oceanography that new young scientists develop their careers, and this project will support a junior researcher who recently completed her postdoctoral work.
