9610009 Businger This project is part of the North Atlantic Regional Aerosol Characterization Experiment (ACE-2) which will be conducted in June and July, 1997 over the subtropical Northeastern Atlantic Ocean as an international collaborative effort. The main objectives of ACE-2 are to study the properties of atmospheric aerosols relevant to radiative forcing and climate using aircraft, ship-board, and ground-based measurements. In a prior NSF-supported project led by this PI, smart tetroons were developed and tested whose altitude could be controlled through variable ballasting achieved using an expandable balloon inside a pressurized constant volume tetroon. Smart tetroons were deployed successfully during the field phase of the ACE-1 experiment in 1995 to track air parcels. Smart balloon track information is provided through an onboard GPS receiver and pressure, temperature, humidity and rainfall sensors which collect additional data that are transmitted along with the position data to a research aircraft. The motivation for the development of this capability was to use the instrumented smart tetroons for data collection and tracking in Lagrangian chemistry and boundary layer physics experiments without the threat of balloon loss through groundings. In this project, the next generation smart balloon will be developed and constructed. The transponder will be enhanced with the addition of two-way communications. This will allow the operating parameters and the altitude control strategy to be adjusted from the aircraft during an experiment, and provide for more efficient data transmission via radio. To overcome the effects of precipitation loading and to extend the pressure range of the balloon in general, the superpressure smart balloon will be constructed from a new fabric which affords a tenfold larger dynamic lift range than the original fabric. The new balloon will also have a spherical shape which provides improved surface area to volume ratio. The instrument package, pumps, and transponder design will be integrated with the new balloon and undergo tests prior to deployment in field experiments.
