32nd Conference on Broadcast Meteorology/31st Conference on Radar Meteorology/Fifth Conference on Coastal Atmospheric and Oceanic Prediction and Processes

Friday, 8 August 2003: 4:15 PM
Quality of Weather Radar Wind Profiles
Iwan Holleman, KNMI, De Bilt, Netherlands
KNMI operates two C-band Doppler weather radars which are amongst others used for obtaining wind profiles. For this, the radars are performing ten-elevation Doppler volume scans four times per hour. One of the Doppler radars, located in De Bilt, is collocated with an operational radiosonde station. About nine months, running from 1 October 2001 until 1 July 2002, of Doppler volume data and radiosonde data have been collected. During this period the radar operation remained unchanged and the radiosonde station performed four launches per day.

Wind profiles have been calculated from the Doppler volume scans using different implementations of the Velocity Azimuth Display (VAD) and Volume Velocity Processing (VVP) retrieval methods. In addition, several procedures for quality control of the mean radial velocity data and the retrieved wind vectors have been implemented. The quality and availability of the obtained weather radar wind profiles have been assessed by comparisons with radiosonde observations.

The comparisons show that the most simple implementation of the VVP retrieval algorithm, using only three fit parameters, provides the best combination of quality and availability of the wind profiles. Furthermore, it is found that the standard deviation of the mean radial velocity as obtained from the VAD/VVP retrieval is a good quality indicator. Finally, a promising method for removal of ``migrating birds'' winds based on filtering of the mean radial velocity data will be presented.

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