Characteristics of wind profiles derived from a stabilized balloon and differential GPS technology

The radar tracked jimsphere was developed in the mid 1960s to support space launch programs requiring more precise winds than could be obtained by conventional systems. The primary advantage of the jimsphere balloon is the roughened surface, which perturbs the air flow, inducing a regular spiraling motion at supercritical Reynolds numbers. The main disadvantages of the system are its expense and the fact that it was not designed to do temperature and humidity sounding. The advent of inexpensive GPS technology has enabled precise tracking of virtually any balloon system. Using ordinary balloons, we find a significant amount of contamination is introduced by spurious motions due to irregular vortex shedding. The addition of a simple narrow sail-like structure to conventional latex balloons is found to induce a more regular, narrow band oscillation at super critical Reynolds numbers. Results are presented from tests of the new stabilized balloon including comparison with near simultaneous radar tracked jimspheres. Results indicate the quality of the data depends, in part, on the length of the train used to loft the sonde. In all cases, the stabilized balloon is found to substantially reduce contamination over conventional latex balloons with the same train length. With train lengths on the order of 10m, the system is found to produce winds that approach radar tracked jimsphere quality.