Directability of the system is being tested through trajectory simulations. Based the the concept of" shear direction", management strategies for single balloons and balloon networks are under development using NCEP Reanalysis winds. Algorithms for targeting a balloon to a specified location, and for flying balloons along latitude circles have been tested. A trajectory forecast model has also been developed to predict the balloon's track for field planning and during tests. Current versions of these models employ climatology for the planning stages and a combination of operational raob data and pseudo-sounding forecasts from the RUC during actual tests.
GAINS development also encompasses balloon vehicle and instrument design. In 1999, the current prototype, an 18-m-diameter superpressure balloon capable of carrying a 90-kg payload, will be launched from Tillamook, Oregon. Operating on solar power, with line-of-sight telemetry and over-the-horizon communications, this prototype will float for 48 hours at 60,000 ft. Data from the Global Positioning System (GPS) provide the location of the balloon and winds at float altitude. Atmospheric sounding capability will be demonstrated. The balloon is equipped with an aircraft transponder (for Air Traffic Control during ascent and descent through the national air space) and with redundant safety devices.
This talk will give an overview of the GAINS program discussing the concept, the motivation for this observing system, and the seven-year development program. Trajectory simulations illustrating the feasibility of the proposed GAINS network will be presented. Finally, status of the program and results of experimental flights will be discussed.
![](images/flag.png)
![](images/blue_ribbon.png)