18th Conference on Weather and Forecasting, 14th Conference on Numerical Weather Prediction, and Ninth Conference on Mesoscale Processes

Tuesday, 31 July 2001
Short-term forecasting at Kennedy Space Center using the ARPS Data Analysis System
Timothy D. Oram, NASA/Spaceflight Meteorology Group, Houston, TX; and T. Garner and J. L. Case
Poster PDF (158.7 kB)
The National Weather Service (NWS ) Spaceflight Meteorology Group (SMG) issues forecasts for emergency and planned landings of the Space Shuttle. Kennedy Space Center (KSC) in Florida is the primary landing site for the Shuttle at the end of a mission and an important emergency landing site during launch and on-orbit activity. Recent improvements in observing systems due to the NWS modernization program and the development of a mesoscale meteorological data network around KSC have resulted in SMG forecasters having to interpret a large volume of data to develop a mental picture of the state of the atmosphere. As a result, tools are required to routinely integrate and assimilate data into a single system in order to simplify the analysis and interpretation of the state of the atmosphere while retaining the capabilities of new data sources. Automated techniques to assimilate data for mesoscale numerical models have advanced over the past decade. These techniques can be used in combination with appropriate visualization tools to provide forecasters with high-resolution, automated analyses of meteorological variables in support of short-term forecasts.

One such data analysis tool was recently installed at SMG during the summer of 2000. With the assistance of the NASA Applied Meteorology Unit, SMG has implemented the Advanced Regional Prediction System (ARPS) Data Assimilation System (ADAS) to assimilate many of the data sources available at KSC. A nested grid with 10-km resolution on the outer grid and 2-km on an inner grid centered over KSC is used. The Rapid Update Cycle (RUC) model serves as the background field for the 10-km grid. The 10-km grid analysis is then used as the background field for the 2-km analysis. GOES-8 visible and infrared imagery, WSR-88D Level III reflectivity and radial velocity data from several Florida sites (Melbourne, Tampa Bay, Jacksonville, and Miami), wind data from 6 Doppler radar profilers, wind tower data, surface routine aviation observations, and ship and buoy observations are currently integrated into the analysis. An analysis is produced every 15-minutes at 00, 15, 30, and 45 minutes after the hour. The analysis is generated 9 minutes after the valid time and uses data received in a 15-minute window surrounding the analysis time.

Successful integration of ADAS into routine SMG forecast operations has occurred in stages. Forecasters must first understand the benefits of a data assimilation and analysis model and be able to view products easily. At SMG, some products displaying weather information significant to Shuttle landing forecasts are automatically created and converted into GIF images for viewing. Forecasters can also use GARP and GEMPAK analysis software to view the analysis grids and create unique displays. Adjustment and tuning of ADAS to obtain the best possible operational analysis requires objective and subjective input from the forecasters. Initial focus for improvement addresses the ADAS cloud analyses and wind products. Cloud ceiling conditions are one of the most difficult forecast and analysis problems for Space Shuttle landings. Crosswinds in May and October 2000 at KSC caused multiple landing delays and a landing site diversion for the first time in Space Shuttle history. ADAS analysis examples, graphics, and comparisons to observed conditions will be presented in this paper.

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