Hurricane Intensity Is More Than Surface Deep
Improving the representation of upper-ocean layers in hurricane forecast models enhances their predictive skill
Hurricanes draw energy from heat at the ocean surface. Thus, the rate at which hurricanes strengthen, or intensify, is highly sensitive to sea surface temperatures (SSTs) in the core of the storm.
Using Hurricane Matthew, a powerful storm from 2016, for comparison, researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory analyzed the degree to which the layers beneath the ocean surface—referred to as upper-ocean stratification—affected SST and hurricane intensity and then applied this new knowledge to forecasts between 2005-2014. They found that an accurate representation of SST under a hurricane—even through relatively simple analytical formulations—can significantly improve the forecasts.
The Statistical Hurricane Intensity Prediction Scheme (SHIPS) is a model used by the National Oceanic and Atmospheric Administration's National Hurricane Center in Miami, Florida, for operational forecasts. In this study, researchers showed that the model's forecasts could be improved significantly by including the effects of ocean temperature, density, and salinity on SST under the hurricane. Better forecasts are important for emergency planning and response in the face of destructive hurricanes.
Reference: K. Balaguru, G.R. Foltz, L.R. Leung, S.M. Hagos, D.R. Judi, "On the Use of Ocean Dynamic Temperature for Hurricane Intensity Forecasting." Weather and Forecasting 33(2), 411-418 (2018). [DOI: 10.1175/WAF-D-17-0143.1]