65th IHC Booklet/Program (pdf - 4.9MB) - Office of the Federal ...

Improvements in the Statistical Prediction of Tropical Cyclone Rapid Intensification
Christopher M. Rozoff 1 James P. Kossin 1,2 , Christopher Velden 1 , Anthony J. Wimmers 1 ,
Margaret E. Kieper 3 , John Kaplan 4 , John A. Knaff 5 , and Mark DeMaria 5
(chris.rozoff@ssec.wisc.edu),
1 CIMSS/UW-Madison; 2 NOAA/NCDC; 3 Private Consultant; 4 NOAA/HRD;
5 NOAA/NESDIS/StAR
The National Hurricane Center currently uses a skillful probabilistic rapid intensification
(RI) index (RII) based on linear discriminant analysis of the environmental and satellite-derived
features from the Statistical Hurricane Prediction Scheme (SHIPS) dataset. In this presentation,
two new probabilistic models for RI prediction, along with the benefits of using an ensemblemean
of multiple models, will be reviewed. The remainder of the presentation will focus on the
benefits of using structural predictors based on microwave imagery.
Two new probabilistic RI models, one based on logistic regression and the other on a naïve
Bayes framework, are evaluated. Both models incorporate data from the SHIPS dataset and have
been developed for a variety of RI thresholds for both the Atlantic and eastern Pacific. Crossvalidation
demonstrates that both models are skillful relative to climatology and that their skill is
competitive with SHIPS-RII. Finally, a three-member ensemble-mean of the logistic, Bayesian,
and SHIPS-RII models provides superior skill to any of the individual members. For a rapid
intensification threshold of 25 kt per 24 h, the three-member ensemble-mean improves the Brier
skill scores relative to the current operational SHIPS-RII by 33% in the Atlantic and 52% in the
eastern Pacific.
This presentation will also highlight improvements in statistical models of RI resulting
from the incorporation of predictors derived from 37-GHz microwave imagery. These predictors
exploit the internal structure of tropical cyclones often obscured from view in geostationary
satellite data. Cross-validation of the logistic RI model in both the Atlantic and East Pacific
shows that adding certain microwave-based predictors improves both the Brier skill score and
probability of detection significantly. Plans to include predictors from 19- and 85-GHz
microwave frequencies will also be discussed.
Session 11 – Page 4