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Evaluation for China L band radiosonde. Dr. LI Wei CMA Meteorological Observation Centre. Distribution on Sites. GTS1-2 & GTS1-2 advanced version. GTS1. RS92 as reference radiosonde. Multiple radiosondes attached on one balloon. Error separating method Principle:
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Evaluation for China L band radiosonde Dr. LI Wei CMA Meteorological Observation Centre
RS92 as reference radiosonde. • Multiple radiosondes attached on one balloon.
Error separating method Principle: (1) If there are enough sample data, the data distribution will be normalization. (2) Two radiosondes with the same sensors between which the statistical systematic errors (SE) should be near zero. And the STD of each them should be approximately equal.
Analytical Methods of Dynamic Measurement Error 1)Taking RS92 as a standard and GTS1, GTS1-2 as tests, the STD of the tests is given by formula (1): (1) 2) As the principle, the separated STD of RS92 is given by formula (2): (2) So the individual STD of RS92, GTS1 and GTS1-2 can be achieved.
Comparative Trial Data description Comparative trials sites : Yangjiang, Xinlinhaote and Nanjing upper-air stations The number of releasing sounding balloons: 65 Available data sets: 59 Methods of trails: Nanjing Yangjiang GTS1-2 RS92 RS92 GTS1-2 GTS1 RS92 GTS1-2 advanced GTS1 RS92 Yangjiang, Xinlinhaote
Pressure hPa GTS1-2 GTS1 hPa
Pressure GTS1-2 advanced version GTS1-2
Temperature GTS1-2 GTS1
Temperature GTS1-2 advanced version
Humidity GTS1-2 GTS1
Wind Direction Wind Speed GTS1 & GTS1-2 (using the same type of L-band radar)
Wind Direction Wind Speed
5. Conclusion • The temperature sensor of radiosonde used in China has been changed from the rod-shaped thermistor to bead thermistor gradually, the measurement accuracy has been improved significantly, and the radiation error has also been effectively corrected. • At present, the GTS1-2 radiosonde has better performance than GTS1, but the humidity measurement still exist a certain gap compared with RS92.
Through software algorithm, bias for pressure measurement can be corrected largely. Current operational wind calculation method has relative large wind pulse affection, and some real results reflecting the wind speed and direction have also been smoothed. The moving average vector method can better eliminate the pulsation effect. If using the 1 minute moving average window to calculate the upper-air wind per second, it can be consistent with GPS wind measurement.