Abstract
Hurricanes play a significant role in the exchange of energy and moisture between the atmosphere and ocean. Mixed layer depth (MLD) and sea surface temperature (SST) variability are two factors that modulate hurricane intensity. Although there are many studies on individual storms, here we analyzed six major hurricanes that traversed across the Gulf of Mexico (GoM) and western Caribbean Sea (WCS) to compare upper-ocean response via the use of Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) microwave imagery along with HYbrid Coordinate Ocean Model (HYCOM) data. Data was analyzed to quantify spatial patterns of ocean response variability and atmospheric boundary layer dynamics along the hurricane track for each storm. Extensive SST cooling with corresponding MLD deepening greater than 100 m in the WCS was observed. Hurricane Charley, a fast-moving eastern GoM storm, did not display a noteworthy effect on MLD, nor did it largely cool the ocean along its track. However, Hurricane Ivan caused substantial SST cooling and MLD variability. Our analysis of SST variations through numerical models and both active and passive remote sensing highlighted distinct cooling patterns linked to each storm. Additionally, chlorophyll-a concentrations were found to increase in areas of reduced ocean temperatures post-hurricane and along impacted coastlines. The forward translational speed of hurricanes was critical in determining SST cooling and MLD outcomes, revealing that fast-moving storms like Hurricane Michael, despite achieving category 5 status, had a lesser impact on MLD compared to their slower counterparts. Notably, a rising trend in hurricane intensity was observed between 2004 and 2018, emphasizing the changing dynamics of hurricane behavior in this region.