Statistical Hurricane Intensity Prediction Scheme with Microwave Imagery (SHIPS-MI): Results from 2006
Daniel J. Cecil CecilD@uah.edu
University of Alabama in Huntsville
A Statistical Hurricane Intensity Prediction Scheme (SHIPS) with Microwave Imagery (SHIPS-MI) was run experimentally at the National Hurricane Center (NHC) and run in parallel at the University of Alabama in Huntsville (UAH) during 2006. Results from the NHC runs will be shown here. SHIPS-MI uses the large scale diagnostic predictors that are generated for SHIPS, and adds predictors taken from satellite passive microwave imagers. These predictors – primarily the mean 19 GHz brightness temperature within 100 km from the cyclone center – are related to the latent heating in the tropical cyclone’s inner core. The SHIPS model’s infrared and oceanic heat content terms are not used in SHIPS-MI, but most of the other predictors are.
Mean absolute errors from SHIPS-MI were slightly smaller (~0.3 kt) than those from SHIPS for a homogeneous set of Atlantic basin forecasts. For the Eastern North Pacific, SHIPS- MI showed a much greater reduction of error (~2.0 kt). Some of this improvement in the Eastern North Pacific may be attributable to using a slightly different set of large scale diagnostic and climatological predictors, besides including the microwave predictors. The SHIPS-MI mean absolute errors for 24 (48) hour forecasts were 9.4 kt (15.9 kt) for the Atlantic and 10.2 kt (11.4 kt) for the Eastern North Pacific. For the same set of forecasts, the SHIPS mean absolute errors were 9.7 kt (16.7 kt) for the Atlantic and 11.6 kt (13.5 kt) for the Eastern North Pacific.
The primary limitation of SHIPS-MI is that the necessary microwave data is not consistently available when needed for forecasts. It requires data from the Special Sensor Microwave Imager (SSMI), Tropical Rainfall Measuring Mission (TRMM) Microwave Imger (TMI), or Advanced Microwave Scanning Radiometer for EOS (AMSR-EOS), all on satellites in low earth orbit. Forecasts are desired for the synoptic times 0000, 0600, 1200, 1800 UTC. At NHC in 2006, SHIPS-MI was run for 77 of 253 possible Atlantic advisories (30%) and 141 of 385 Eastern North Pacific advisories (37%).