Geophysical Research Letters

Oceanic and atmospheric anomalies of tropical instability waves



Tropical instability waves (TIWs) are detected in remotely-sensed sea surface height (SSH), temperature (SST), and wind records of the eastern equatorial Pacific. Analyses of TIW anomaly relationships reveal strong dynamical influence of TIWs within approximately 5° of the equator. The first influence is advective heat flux. The primary forcing of TIW SST anomalies is advection of the meridional temperature gradient by TIW currents. The second influence is modification of the wind stress and Ekman pumping fields by TIW surface ocean currents. By affecting surface stress and hence roughness, TIW currents in this low-wind region introduce a significant bias in scatterometer vector wind measurement. This bias is evident in both NSCAT and QuikSCAT winds. The difference between wind measurements from TAO moorings and scatterometers is phase-locked with TIW SST oscillations. These results have important implications for scatterometry and for understanding tropical dynamics, thermodynamics and biogeochemistry.