Eastern Pacific Ocean heat content estimates from altimetry for operational hurricane intensity forecasts

As part of a NOAA Joint Hurricane Testbed effort, an Eastern Pacific (EPAC) oceanic heat content (OHC) estimation scheme was developed for use in the Statistical Hurricane Intensity Prediction Scheme for predicting hurricane intensity. The approach follows those made operational for hurricane intensity forecasts from SHIPS in the Atlantic Ocean Basin. In the EPAC, the modified algorithm computes OHC from multiple platform radar altimeters and sea surface temperatures from TRMM microwave imager. Altimeter data are smoothed, combined and objectively analyzed to a 0.5^o grid to estimate isotherm depths and OHC variations based on a seasonal climatology. Estimates from 2000 to 2006 were compared to several sets of thermal structure measurements from NOAA's Tropical Atmosphere Ocean (TAO) buoys. Within the context of a two-layer fluid, satellite-derived estimates were in good agreement with the in situ data. Regression analyses revealed RMS differences of a few meters in isotherm depths and OHC estimates of less than 8 KJ cm^-2.