Eyewall Wind Profiles in Hurricanes Determined by GPS Dropwindsondes

In 1997, NOAA and Air Force Reserve hurricane reconnaissance aircraft began to deploy Global Positioning System (GPS) based dropwindsondes in the hurricane eyewall. These instruments provide, for the first time, detailed (5 m vertical resolution) accurate (0.5-2.0 ms-1) profiles of the inner core of a hurricane from flight level (typically 700 mb) down to the surface. Nearly 200 such profiles have been obtained through the 1999 hurricane season. This paper will document the mean wind structure of the lower 3000 m of the hurricane eyewall, determined from the existing sample of eyewall dropsonde profiles. Implications for operational estimates of hurricane intensity will be discussed.