Presented on April 5, 2023, by

Niklas Schneider
Director, International Pacific Research Center
Professor, Department of Oceanography
University of Hawai’i at Mānoa


The Gulf Stream Convergence Zone is a dipole of long-term averaged surface-wind divergence and convergence over the cold and warm flanks of the Gulf Stream, respectively. Using satellite observations of equivalent neutral winds and sea surface temperatures, we show that this dipole results from the aggregation of the atmospheric boundary layer responses to the Gulf Stream sea surface temperature front and winds of transients in the North Atlantic storm track. The boundary layer is based on observed impulse response functions for surface wind divergences, and captures modulations of boundary layer vertical mixing and atmospheric pressure over, and downwind of, ocean mesoscale sea surface temperatures. When forced with observed mean sea surface temperatures and synoptic-scale winds, the empirical boundary layer recovers the long term dipole of surface divergence, and the preponderance of surface wind divergence and convergence when winds are in the direction of, or opposed to, gradients of sea surface temperatures, respectively. These sea surface temperature impacts can also be seen in strong surface wind convergences associated with mid-latitude cyclones and fronts.