Statistical Models of Holland Pressure Profile Parameter and Radius to Maximum Winds of Hurricanes from Flight-Level Pressure and H*Wind Data

In many hurricane risk models the inclusion of the Holland B parameter plays an important role in the risk prediction methodology. This paper presents an analysis of the relationship between B and a nondimensional intensity parameter. The nondimensional parameter includes the strong negative correlation of B with increasing hurricane size [as defined by the radius to maximum winds (RMW)] and latitude as well as a positive correlation with sea surface temperature. A weak positive correlation between central pressure deficit and B is also included in the single parameter term. Alternate statistical models relating B to RMW and latitude are also developed. Estimates of B are derived using pressure data collected during hurricane reconnaissance flights, coupled with additional information derived from the Hurricane Research Division's H*Wind snapshots of hurricane wind fields. The reconnaissance data incorporate flights encompassing the time period 1977 through 2001, but the analysis was limited to include only those data collected at the 700-hPa-or-higher level. Statistical models relating RMW to latitude and central pressure derived from the dataset are compared to those derived for U. S. landfalling storms during the period 1900-2005. The authors find that for the Gulf of Mexico, using only the landfall hurricanes, the data suggest that there is no inverse relationship between RMW and the central pressure deficit. The RMW data also demonstrate that Gulf of Mexico hurricanes are, on average, smaller than Atlantic Ocean hurricanes. A qualitative examination of the variation of B, central pressure, and radius to maximum winds as a function of time suggests that along the Gulf of Mexico coastline ( excluding southwest Florida), during the final 6-24 h before landfall, the hurricanes weaken as characterized by both an increase in central pressure and the radius to maximum winds and a decrease in B. This weakening characteristic of landfalling storms is not evident for hurricanes making landfall elsewhere along the U. S. coastline.