TECHNIQUES FOR OBJECTIVE HEMISPHERIC ANALYSIS AND PREDICTION OF THE JET STREAM
Abstract
The objective hemispheric analysis technique incorporates information from data areas into level of maximum wind (LMW) analyses for no-data areas. This is done in a quantitative, objective, and consistent manner by using LMW regression equations that specify the initial-guess fields for the analysis. The analysis technique locates jet cores between grid points, and generates observations along these cores by using horizontal jet profiles. This technique produces high-quality analyses that compare favorably with subjective analyses, and that are generally consistent with one another. The first prediction technique is based on a procedure wherein potential predictors are obtained from a network grid oriented with respect to the LMW wind direction at the predictand point. Prediction equations are obtained by applying the screening regression technique to predictors selected from initial-state LMW parameters (and their 12-hr change) and wind speed values at constant pressure surfaces. Tests on independent data showed that these equations produce prognoses that are better than persistence for all polar and subtropical jetstream categories. The second prediction technique applies diagnostic LMW regression equations (originally derived to produce the initial-guess fields in the LMW analysis) to constant- pressure-surface numerical prognoses.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1965
- Accession Number
- AD0622711
Entities
People
- Bernard J. Erickson
- David B. Spiegler
- John T. Ball
- Robert J. Ball
Organizations
- United Technologies Corporation