Enhancements to the AFGL (Air Force Geophysics Laboratory) Statistical Analysis Program (ASAP) for the Global Multivariate Analysis of Heights and Winds
Abstract
This report documents changes to and experiments designed to test the impact of these changes on the AFGL Statistical Analysis Program (ASAP) of heights and winds on the model sigma surfaces. Key enhancements include a new, simpler and more efficient method of converting pressure layer temperatures into sigma level heights, a corrected and improved handling of the least squares equations and a new solver for these systems of equations based on standard LINPACK routines. We conducted several offline tests of the new versions of procedures SATLTMP and ASAP2 which embody these enhancements to verify their correctness, to compare their results to results of the earlier versions and to tune certain control constants. We then conducted a one week data assimilation experiment, using simulated data to examine the impact of the enhanced ASAP. The changes made to ASAP have enhanced its consistency and operation. Separate studies of the satellite profile data preprocessing and the specification and solution of the normal equations demonstrated that the changes made are desirable. The overall positive impact of the enhancements is small as measured by a one week data assimilation experiment based on simulated data. Keywords: Data assimilation; Numerical weather prediction; Objective analysis; Optimal interpolation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 17, 1988
- Accession Number
- ADA202912
Entities
People
- Mark Mickelson
- Ross N. Hoffman
- Thomas Nehrkorn
Organizations
- Atmospheric and Environmental Research, Inc