A NUMERICAL FORECASTING INVESTIGATION USING THE EQUATION OF MOTION
Abstract
The equations governing the time rates of changes of wind speed and direction were simplified to check the orders of magnitude of their principal terms and the accuracy with which they can be determined to provide a positive aid in wind forecasting. The 2-day test period covered a time during which the maximum number of observations were available. Figures are presented for 16,000- ft streamline-isovel maps and 500-mb contours. Forecast maps are included of the isogon and isovel fields; these provide 2 history maps and a verification map. The results of the study were largely negative. The belief that the wind fields should enter directly into the wind prognosis was unchanged. The conclusion was that either better smoothing techniques or simultaneous wind and pressure analysis are required to determine accurately wind speed and direction tendencies. Some indication was obtained that the advective parts of these tendencies can be used in a qualitative way to improve wind forecasts. Measurements of the vertical advection and pressure influence indicated at least as large a contribution to wind tendencies as the horizontal advection term. If these results are verified, the vertical linkage resulting from the ageostrophic and vertical velocity terms would be the controlling factor in the determination of wind-field forecasts.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1953
- Accession Number
- AD0016368
Entities
People
- John C. Joern
- Leon Sherman
Organizations
- Florida State University