Estimation of Vertical Wind Shear from Infrared and Microwave Radiances.
Abstract
Linear regression estimates of radiosonde observed vertical wind shears between mandatory levels were made, using radiance gradients obtained via the TIROS-N satellite as predictors in a pilot experiment based on about 200-500 observations. The best results were obtained for shears between 850 mb and a level in the upper troposphere, such as 300 mb. Results were similar for 850-400 or 850-200 mb shears, but notably inferior for 850-500 mb shears. The linear correlation coefficients between estimated and smoothed observed components of shear was about 0.70, corresponding to about 50 percent explained variance in independent test samples. Somewhat higher explained variances (about 0.60) were achieved in a limited trial where the data-set was stratified according to subjectively-judged trajectory curvature. Estimates of the wind itself in the upper troposphere were nearly as skillful as the best shear results. Overall, with the possible exception of curvature-stratified estimates in clear regions, both wind and wind shear estimates are not likely to be superior to methods that generate RMS wind errors of order 5m/s. Most of the information was contributed by the linear combination of microwave channel 2 minus microwave channel 3. Some additional information may be obtainable from the infrared (HIRS-2) channels 3, 4 and 5 (especially 5). (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1981
- Accession Number
- ADA100439
Entities
People
- Anthony Cavalier
- Frederick Gadomski
- Hans A. Panofsky
- John J. Cahir
Organizations
- Pennsylvania State University