Tropical storms are rapidly rotating storm systems with an organized center over warm tropical oceans and maximum sustained surface winds ranging greater than or equal to 39 mph. These storms can range dramatically in size and produce many hazards to the affected areas, such as storm surge, coastal flooding, inland flooding, destructive winds, and tornadoes.
Much research has been done on the impact tropical cyclones (tropical storms with maximum sustained surface winds ranging greater than or equal to 74 mph) have on drought, but the contribution of weaker tropical storms on the drought intensity in the US is not often investigated. Research shows that rainfall is not always proportional to the wind scale of the tropical cyclone and therefore, in some cases, tropical storms may produce more rainfall. Researchers are now asking whether tropical storms can help mitigate and alleviate agricultural drought conditions in the affected areas.
In a new AGU Earth’s Future article, authors J. Y. Song, P. Abbaszadeh, P. Deb, and H. Moradkhani use high spatial resolution soil moisture data to find if agricultural droughts are improved or exacerbated when Atlantic tropical storms occur in the contiguous United States (CONUS).
The study reveals that states on the eastern coastline in the US are more likely to be affected by tropical storms and weakened agricultural droughts, including Tennessee and Kentucky. In addition, agricultural droughts in Texas, Louisiana, Mississippi, and Florida are less influenced by tropical storms. These states are near to the location where some of the more powerful and destructive tropical storms made landfall, implying agricultural drought in the Gulf of Mexico is relatively irrelevant to tropical storms. Whereas, agricultural droughts in the eastern coastal states such as Virginia, Delaware, Maryland, New Jersey, and the District of Columbia are more likely to be affected by tropical storms in either a positive or a negative way.
Funding for this project was provided by the NOAA Climate Program Office, MAPP program.
Read the full study here.