¶ Scanning ARM Precipitation Radar (SAPR)
¶ Overview
Multiple precipitation radars have been or are being deployed at the various ARM facilities.
More information of radars in general can be found here: General Information on Radar
¶ Data Quality Plots
There are many ways in which to monitor the health of radars. The following are a few tests that the DQ Office is implementing and are likely to change.
¶ Diagnostic Plots
The diagnostic plot, Fig. 1, has multiple plot windows. The first plot is of a point target reflectivity. A point target is a stationary object suchas a bridge, tower, railroad, etc... that the radar can observe. Since this object does not change, the observation of it from the radars perspective should not change, neglecting atmospheric conditions. We can use this target to monitor the calibration of the radar over long periods of time.
The second and third plots are the max and min values of Zh and Zdr, respectively, for each file.
The fourth plot is the standard deviation of reflectivity (DZ), differential reflectivity (DR), and doppler velocity (VR).
The fifth plot is of the percentage of points in a file labeled as "bad" by the radar processing for reflectivity and differential reflectivity.
The last plot is the scanning mode of the radar for each time sample.
Vertical Point Mode
Sometimes the radars will sit in vertical point mode (VPT), during which they continuously stare at approximately 90 degrees. This is similar to the operation of the KAZR.
Reflectivity Profile Over the Main Site
This plot is of the vertical profile of reflectivity over the main site (SGP C1, NSA C1, TWP C1). This is used to compare with the other instruments at the site.
¶ Beam Pattern
Using the point target described earlier, the beam pattern of a radar can be determined. See the section Point Targets under General Information on Radar for more information.
This plots out multiple days of the beam pattern for the radar. If there is a significant change in the pattern, then there is possibly a problem with the radar antenna.
Movies
There are currently 2 sets of movie loops for the radars. Both sets consists of movies for each of the radar variables. The first set is from the full volume scans and includes a PPI image and an RHI slice from the data in the volume. THe second set are from the RHI scans and have a noticeable higher resolution than the PPI from the volume scans.
Comparison Plot
The final plot is a comparison plot of various instruments over the site's major facility. These will be dependent on each site and the instruments available for comparison.
At the SGP site, the plots will consist of data from the KAZR, XSAPR @ I4/I5/I6, Micropulse Lidar, Ceilometer, Doppler Lidar, Radar Wind profiler, Disdrometer, and 2D Video Disdrometer.
