Status and Future Direction of Operational Radar Application at KNMI

The national weather service of the Netherlands, KNMI, operates two Gematronik C-band Doppler radars. Currently, the reflectivity data are employed operationally for the synthesis of composites of pseudoCAPPI products and echotop products. The quality of the Doppler data and the potential of this data for operational applications is still under investigation.

For the production of pseudoCAPPI images, anomalous propagation clutter is removed from the raw images using a statistical method. The inherent fluctations of Rayleigh-scattered precipitation signal and the relative stability of clutter signal are used to flag clutter-contaminated pixels in a reliable way. Three-hourly estimates of accumulated precipitation are calculated rountinely by adding the pseudoCAPPI products. Via a comparison of daily versions of these estimates to the accumulated-precipitation distribution obtained from a dense network of rain gauges, corrections for systematic errors of the radar data have been revealed. The radar estimates of accumulated precipitation will be corrected for these errors. For the production of echotop maps, an algorithm is used that corrects for errors due to the finite width and sidelobes of the radar beam.

To fully exploit the potential of radar (reflectivity) data, a tool for the detection and display of severe weather phenomena related to convective systems is being developed. The development of a product for the detection of summer hail has been completed. The hail detection product uses both radar reflectivity data and temperature information from a numerical weather prediction model. It has been verified extensively using hail observations and damage reports. Investigation into the potential of radar (reflectivity) data for estimation of the maximum velocity of convective wind gusts is still ongoing.

In the presentation, an overview of the current products will be given and special features of the processing will be highlighted. In addition, the latest results on the quality assessment of the Doppler data will be presented.