Hurricane track forecasting has improved steadily over the past three decades whereas the forecasting of hurricane intensity changes has not, due mainly to insufficient real-time oceanic and atmospheric information. In this paper, we investigate the intensity changes of recent hurricanes (Ivan, Katrina and Rita) during crossings of the Gulf of Mexico and relationships with the Loop Current, detached warm core rings, and cold core eddies. Our primary goal is to assess the role that real-time satellite measurements can play in providing better predictor variables for hurricane intensity changes.

GOES-E satellite measurements were used to quantify sea surface temperature changes resulting from ocean to atmosphere heat and moisture fluxes, caused mainly by hurricane winds. Sea surface height measurements were used to identify distinct water masses as the surface temperature structure can be quite uniform across the Gulf during summer, reducing ocean feature detection before hurricane passages. Sea surface temperatures (SSTs) were computed from the mid-infrared channel (3.5-3.9 micron) of GOES GVAR using night-time data only. The major advantage of using GOES GVAR data in oceanography is its high frequency repeat coverage (every 15 minutes over the Gulf) which enables removal of much water vapor and cloud contamination through the use of the warmest pixel compositing technique on a series of night-time images. Satellite altimetry measurements provide the only remote sensing technique that directly measures a dynamical variable of ocean state - the sea surface height (SSH). Detection of mesoscale eddies has been improved by combining multi-mission measurements from TOPEX-Poseidon, ERS-2, GFO, Jason-1 and Envisat into a gridded product, updated daily (http://argo.colorado.edu/~realtime/welcome). Integration of GOES SST and SSH data can be found at http://www.esl.lsu.edu.

The cyclonic winds within Hurricane Ivan in September 2004 enhanced the cyclonic circulation in two large areas north and south of a detached warm core ring of the Loop Current. Cooling of 3-7 C was measured over 39,000 km² producing SSTs below 26 C, a known lower limit for hurricane maintenance. NHC wind data showed a decrease in sustained maximum wind speeds as Hurricane Ivan interacted immediately with the cool water as it crossed the Gulf. The following year, Hurricanes Katrina and Rita exhibited rapid intensification from category 1 to category 5 in close proximity to the high heat content Loop Current and detached warm core rings, however both hurricanes experienced weakening before landfall in close proximity to self-generated cool wakes within cold-core ocean cyclones adjacent to warm core rings. These results demonstrate the importance of both cyclonic and anticyclonic eddies in producing hurricane intensity changes. A focused effort to incorporate more accurate information on mesoscale cyclonic eddies and cool wake predictions could benefit hurricane intensity modelling efforts.