The accuracy and performance of the new Vaisala RS90 radiosonde in operational use

The total uncertainty of upper air radiosonde observations depends on many different sub factors, such as; performance of the sensor itself, references used in the radiosonde factory calibration process, quality of the ground check performance, fitting errors of the calibration curves, uncertanties caused by the measuring electronics, quality of the telemetry, sensor lag errors, and sensor solar and infrared errors. This PTU -measurements accuracy chain has been modeled from the sensor design through factory calibration to the TEMP report produced by the ground receiving system. The higher performance of the Vaisala RS90 type radiosonde has an positive impact on synoptic and research observations.

In this paper, the accuracy chain of PTU -measurements from factory calibration to the TEMP message is evaluated and the total uncertanties of soundings are introduced and compared with actual data from the field.

Several improvments have been made to GPS-derived upper air wind measurements using the RS80. These improements have now been implemented in the RS90 design and its associated computation algorithms. The effect of these improvements has been analysed for performance and reliability and compared with collected operational data from the field.