Intercomparison of Atmospheric Soundings from the Aerosonde and Radiosonde

Abstract

This paper presents a preliminary evaluation of meteorological measurements made by the Aerosonde (using Vaisala, Inc., RS90 sensors) by comparing them with closely correlated measurements made using traditional balloonborne sondes (Vaisala RS80-A/-H). Eighteen comparisons were completed in temperatures ranging from ?20° to 10°C. Although the Aerosonde generally performed well in comparison with the radiosonde, calibration errors and time-lag errors similar to those observed between radiosonde and dropsonde observations were evident in some of the temperature and relative humidity profiles. The average temperature differences between the Aerosonde and radiosonde profiles varied between 0.01° and 1.2°C, with the Aerosonde observations being consistently warmer than the radiosonde measurements. A dry bias was also generally present in the radiosonde relative humidity observations relative to the Aerosonde observations. Wind observations were comparable. Mean wind magnitude differences ranged from 0.02 to 1.7 m s?1, with the mean wind direction differences between 0.1° and 19.1°. After application of ground-check corrections, the most prominent causes of disparity between the Aerosonde and radiosonde profiles are the inevitable temporal and spatial dislocation between the Aerosonde and radiosonde soundings and aerodynamic factors that influence the Aerosonde sensor measurements. These differences are inherent in this very different observing platform. Kinetic heating, the different sensor types, chemical contamination, storage and handling inconsistencies, and sensor age are likely to play a lesser role.