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
hetween 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 playa lesser
role.
