A partnership between researchers is enhancing hurricane forecasting by factoring in the effects of sea spray in models that predict hurricane activity.
Hurricanes are vast and intricate systems that can cover hundreds of miles as they rotate around the storm’s eye’s low-pressure center. In such complex conditions, estimating the potential growth of a hurricane poses a significant challenge.
A new partnership between scientists in South Korea and Florida State University is making advancements in hurricane forecasting by integrating sea spray effects into predictive models for hurricane behavior. This research was published in Environmental Research Letters.
“While hurricane track predictions are generally accurate, intensity forecasts have not been as reliable, and we’re investigating the reasons behind that,” explained Mark Bourassa, a professor from FSU’s Department of Earth, Ocean and Atmospheric Science and one of the paper’s co-authors.
As hurricanes move over the ocean, the surface winds and waves create droplets of seawater that are launched into the air, referred to as sea spray. When these warm water droplets evaporate, they cool down while simultaneously releasing heat and moisture into the air just above the ocean’s surface. This heat contributes to lifting more moisture-rich air, a key factor in driving hurricanes.
The researchers analyzed data from probes deployed by hurricane-hunter aircraft and discovered significantly more thermal energy being transferred from the ocean to the atmosphere than they had anticipated. This finding suggested a previously underestimated element that impacts storm intensity.
Past research focusing on the influence of sea spray on intensifying hurricanes often relied on indirect measurements, such as wind speed, to estimate how sea spray decreases drag; this, in turn, enhances storm intensity in models. However, these estimates did not accurately reflect how spray increases the energy that fuels storms, particularly at wind speeds over 20 meters per second.
The weather model utilized by the South Korean and FSU researchers included a wave model to improve the precision of sea spray generation and accounted for variations in the heat and moisture transferred to the atmosphere.
“We’ve been overlooking a substantial amount of energy in these storms,” Bourassa noted. “When we integrated data showing how sea spray alters heat and moisture flow in a storm, we found that the intensity forecasts became significantly more accurate compared to when the model was run without that adjustment.”
To validate their findings, the research team examined four major hurricanes from the Atlantic Ocean—Ida (2021), Harvey (2017), Michael (2018), and Ian (2022)—which caused extensive damage in the U.S. They also looked at four typhoons from the Pacific Ocean with assistance from their colleagues in Korea.
While current scientific methods are generally effective at predicting a hurricane’s trajectory, meteorologists aim to refine their models to enhance understanding and predictions of storm intensity. This research indicates that operational models could be adjusted to provide improved intensity forecasts.
Future studies inspired by this research may focus on the rapid intensification of storms, Bourassa stated, contributing to unraveling the complexities surrounding hurricane forecasting.
The FSU research team comprised Chaehyeon Chelsea Nam, an assistant professor in the Department of Earth, Ocean and Atmospheric Science; DW Shin and Steven Cocke, research scientists at FSU’s Center for Ocean-Atmospheric Prediction Studies; Sinil Yang from the APEC Climate Center in South Korea; Dong-Hyun Cha from Ulsan National Institute of Science and Technology; and Baek-Min Kim from Pukyong National University in South Korea.
This research received support from various organizations, including the Korea Hydrographic and Oceanographic Agency, the Ministry of Oceans and Fisheries of Korea, the Korea Environment Industry & Technology Institute, the Korea Ministry of Environment, the National Research Foundation of Korea, and the Korea Meteorological Administration Research and Development Program.
