A Technique for Predicting Surface Wind Distributions of Tropical Cyclones in the Western North Pacific.
Abstract
Accurate initial estimates and forecasts of radii of winds over 30 kt and 50 kt around tropical cyclones are important requirements for Navy decision-making and operations. This report describes a diagnostic study of tropical cyclone surface wind distribution that was conducted by using data extracted from tropical cyclone warnings issued by the Joint Typhoon Warning Center, Guam, during the period 1966-77. Results from two different data analyses show that: (1) The tangential wind speed along the radial axis decreases exponentially outward from the radius of maximum wind; (2) In addition to persistence, the change of a tropical cyclone's size depends only on the change of the maximum wind; and (3) The asymmetric shape of the isotachs correlates highly to the speed of movement. Based on these findings, a statistical wind-radius forecast model was formulated and tested on independent 1979 data. Results show that a time lag exists between the change of maximum wind and the change of wind radii, which suggests that the wind-pressure gradient adjustments may originate from the inner core of the storm and slowly propagate outward. The results also indicate that the statistical forecast model possesses a skill equal to that of an average JTWC forecaster's wind radius forecast. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1982
- Accession Number
- ADA122034
Entities
People
- L. Robin Brody
- Samson Brand
- Ted L. Tsui