Coastal Downwelling Study Selected as a Featured Paper

A recent study authored by five NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML) scientists (Lew Gramer, Jun Zhang, Ghassan Alaka, Andrew Hazelton, and Sundararamen Gopalakrishnan) was recently selected out of a variety of publications as a featured paper for EOS Science News by the American Geophysical Union

Using a state-of-the-art hurricane modeling system developed at AOML, the Basin-Scale Hurricane Weather Research and Forecasting (HWRF-B) model, scientists found coastal downwelling factors such as increased heat and moisture, transfer into the atmosphere, creating an environment suitable for hurricane intensification. The analysis and modeling of coastal downwelling enables better understanding, prediction and forecasting of hurricane intensification prior to making landfall, thus having crucial implications for public safety.

Caption: A diagram shows the process of coastal downwelling, which has been found to impact the intensity of landfalling hurricanes. Image credit: American Meteorological Society.

Using the coupled model and buoy observations, Gramer et al. analyzed three 2020 Atlantic hurricanes, Eta, Hannah, and Sally, that intensified as they approached land. The study showed coastal downwelling occurred when hurricane winds blew parallel to the coast, which led to rising water levels along the coast. This process brought warm surface water over the continental shelf, further intensifying the landfalling hurricanes. 

To understand the complex system of coastal downwelling, we must improve how the coastal ocean is represented in hurricane forecast models. This is done by continuing to observe the coastal ocean using aircraft-deployed instruments, autonomous vehicles, and ocean moorings. 

This research was conducted with support from the Hurricane Forecast Improvement Program (HFIP), as well as funding from the Hurricane Supplemental.

Citation: Gramer, L. J., Zhang, J. A., Alaka, G., Hazelton, A., & Gopalakrishnan, S. (2022). Coastal downwelling intensifies landfalling hurricanes. Geophysical Research Letters, 49, e2021GL096630.