Characteristics of High-Resolution Wind Profiles Derived from Radar-Tracked Jimspheres and the Rose Processing Program

Abstract

Results are presented from an investigation to estimate the limiting accuracy of atmospheric wind measurements obtained from a radar-tracked jimsphere and the data reduction program. The current system used to support space launches includes the jimsphere balloon, the radar, and the data processing system. Characteristics of the derived wind profiles are examined by spectral analysis of the radar tracking data and the derived wind profiles. Consistent with earlier work, the quality of the resulting wind profile is found to depend on the slant range of the balloon. In the current data processing systems, however, no explicit attempt is made to remove the effect of the regular oscillation of the jimsphere. The limiting accuracy of the system at low altitudes is found to be the result of aliased self-induced balloon motion in the wind profile. The magnitude of the error resulting from the aliased balloon oscillation decreases from 0.5 m s?1 near the surface to near zero at about 12 km in proportion to the jimsphere rise rate. Radar noise adds to the errors in the wind profile and increases with slant range. For independent layer averages of about 30 m, the resulting accuracy is 0.5?0.7 m s?1 in most tracking conditions. The effective vertical resolution of the system is found to increase in magnitude with altitude and slant range. Near the surface it is possible to resolve vertical features on the order of 150 m. At altitudes over 12 km at long slant ranges the effective vertical resolution decreases to 300 m.