CAX1 ZDR bias

In theory, horizontal views of light raindrops should appear spherical and yield ZDR values of 0.0.
For entire CAX1 dataset with 5-min scan cycle, the median ZDR for each low level 1.5deg PPI (DOPVOL1_A) scan was calculated for light rain pixels (minimum threshold=1500) meeting the following criteria,
•	RhoHV < 0.985
•	2.0 < range_km < 30.0 (below the Bright Band)
•	+10.0 < DBZ < +20.0
To remove the possible effect of radome wetting, those times identified by the co-located FD12P using a precipitation rate threshold of > 0.01 mm/h, were not included in the calculation of a daily mean ZDR bias.
For the entire dataset the mean ZDR bias was determined to be 0.75dB with a standard deviation of 0.13dB.
There was no significant day to day variation of overall ZDR bias over the course of the campaign.
No ZDR bias correction has been applied to submitted CAX1 dataset.