Accession Number : ADA188861

Title :   Baseline Observing System Experiments Using the AFGL Global Data Assimilation System.

Descriptive Note : Technical rept.,

Corporate Author : ATMOSPHERIC AND ENVIRONMENTAL RESEARCH INC CAMBRIDGE MA

Personal Author(s) : Louis, J F ; Hoffman, R N ; Nehrkorn, T ; Baldwin, T ; Mickelson, M

PDF Url : ADA188861

Report Date : 18 Nov 1987

Pagination or Media Count : 66

Abstract : Four observing system experiments each includes one week of data assimilation during each special observing period of the FGGE year, and 3 four day forecasts, starting from the 3rd, 5th and 7th day of the assimilation periods. The first experiment (STATSAT) provides a baseline for the others and uses all the available level II-B FGGE data, except surface observations. Comparisons with the NMC level III-A analyses show that the AFGL system performs adequately. In the 2nd experiment (NOSAT) all satellite data are removed from the data set. As expected the impact on the analysis is small in the Northern Hemisphere, out large in the Southern Hemisphere. This experiment provides a measure of the sensitivity that can be expected from future experiments in which different satellite retrieval techniques are tested. The 3rd experiment (NOCON) was designed to test the degradation of the analyses when all conventional data are denied and only satellite data are used. Differences between this and the STATSAT experiment appear first over continental areas but propagate quickly over the oceans, especially in the winter.

Descriptors :   *WEATHER FORECASTING, *DATA PROCESSING, ASSIMILATION, DEGRADATION, GLOBAL, INFORMATION RETRIEVAL, NORTHERN HEMISPHERE, SENSITIVITY, SOUTHERN HEMISPHERE, SURFACES, WINTER, METEOROLOGICAL SATELLITES, DATA ACQUISITION

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE