Study Investigates Influence of Hurricanes on Ocean Surface Currents
May 4, 2017
Scientists used GPS data collected from ocean drifters during Hurricane Isaac with a coupled atmosphere-wave-ocean model to better understand how hurricanes affect upper ocean circulation. The researchers found that hurricane-induced Stokes drift (wind-wave-driven water mass transport) created a cyclonic rotational flow to the storm’s left and an anticyclonic rotational flow to its right. Stokes drift accounted for more than 20% of the average current’s velocity and changed its direction up to 90 degrees, significantly enhancing shoreward upper ocean transport on the storm’s right side. The team estimated that the spread rate for these surface flows was 6 times larger than before the storm, a significant deviation from recognized measurements of lateral dispersion during non-hurricane conditions. The scientists published their findings in Geophysical Research Letters: Hurricane-induced ocean waves and stokes drift and their impacts on surface transport and dispersion in the Gulf of Mexico.
Previous research has demonstrated the importance of Stokes drift in local upper ocean circulation. However, Stokes drift’s effect on storm-scale surface currents has never been studied using in situ observations and coupled modeling. Because hurricanes produce extremely high winds and waves that significantly impact upper ocean circulation and water mass transport, it is important to better understand and predict their influence during events like the 2010 Deepwater Horizon oil spill.