Exploration of Real-time Satellite Measurments to Advance Hurricane Intensity Prediction in the Northern Gulf of
Nan Walker, Robert Leben, Steve Anderson, Alaric Haag, Chet Pilley, Mitsuko Korobin
The accurate prediction of hurricane track and intensity is an important endeavor for improvement of public safety during hurricane season. Our overall goal in this research is to assess the potential role that different sources of real-time satellite data can provide to improve hurricane intensity forecasts. We focus on investigating the role that ocean features played in the intensity changes that transpired during the passages of five major hurricanes in the Gulf of Mexico (GoM) between 2004 and 2008 (Ivan, Katrina, Rita, Gustav, Ike). Research has shown that intensity is partially controlled by the underlying ocean temperature and mixed layer ocean heat content (OHC). In the Gulf, regions of high OHC (the Loop Current and warm-core eddies) have the potential of decreasing hurricane intensity. And essential ingredient of air-sea interactions is the hurricane's production of a "cool wake", a region near its path that has the potential of providing negative feedback to intensity. We investigate the development and characteristics of the five cool wakes in detail. In this endeavor, we used several sources of satellite measurements available in near-real-time: infrared measurements and night-time composites of sea surface temperature (SST) from GOES-12, gridded sea-surface height (SSH) maps derived from multiple-satellite altimetry, and microwave SST measurements from TMI and AMSR-E. Atmospheric data included the National Hurricane Center storm track and maximum sustained wind speeds; scatterometer wind measurements; and GOES-12 satellite-tracked winds.
Our analysis demonstrated that three of the five hurricanes intensified over the Loop Current and WCEs while three of the hurricanes weakened in close proximity to the cool wakes that they generated. We found that each cool wake was unique. In all cases, areas of maximum cooling were co-located with regions of cyclonic circulation close to the hurricane's track. Cool wake generation was clearly dependant upon the path of the hurricane in relationship to the position and strength of ocean cyclones. We observed no correlation between hurricane intensity and either the magnitude of temperature change, minimum temperature generated, or size of the cool wake. Based on our results, we conclude that the surveillance of ocean features in the GoM is essential for the advancement of hurricane intensity modeling and prediction. Further study of cool wakes and intensity changes is recommended. Advancement of hurricane intensity prediction would benefit from improved ocean mesoscale sampling afforded by more operational satellite altimeters on orbit.