35GHz CloudRadar Images

Since 25th of February 2004 KNMI supports near real-time processing of the 35 GHz Cloudradar in Cabauw. The products shown here are preliminary

NOTE: during the winter season of 2011/2012 we will again perform sometimes measurements in what we call the "fog-mode". During these measurements the beam of the radar is pointing almost horizontal instead of vertical!!

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radar dBZe
velocity
spectral
width

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Introduction to Images

radar backscatter

The cloudradar measures in a so-called uncoded and coded mode. The backscatter presented here is an average of these two modes. Note that the backscatter signal is from clouds droplets, precipitation and/or in the lowest kilometers (except in winter) it can also be from insects. In the plot with the lidar-ceilometer cloudbases included, the radar dBZe's below the cloudbase indicated by the ceilometer are most likely from insects or from precipitation below the clouds. The thick black line at the bottom of the plot indicates when data have been taken by the radar. Note that thin water clouds might not be detected by the radar as the small droplets in these clouds have a too small backscatter cross section to be detected, and clouds of small vertical extension sometimes are "lost" in the cloudmasking processing.

Examples of different cloudtypes will be included here in the future. For a brief explanation and examples of a 95 GHz cloudradar at Chilbolton (UK) click here.

vertical velocity

When valid the velocity is taken only from the uncoded mode. Otherwise the velocity data are derived from the coded mode (if valid of course). Note that in the display positive velocites are downwards!

spectral width

The radar measures in full Doppler mode and from the maximum peak in the Doppler spectrum the width is presented here. The spectral width is usually larger e.g. in more turbulent regions or in rain.

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This site is maintained by Henk Klein Baltink