Analysis of Vertically Pointing Millimeter Wave Radar Data Quality at the ARM Eastern North Atlantic Site

The Department of Energy’s Atmospheric Radiation Measurement (ARM) radar program consists of 33 radars of various wavelengths at many locations around the world, with the goal of providing the best possible data to scientists. To work towards this goal, the ARM Eastern North Atlantic (ENA) site’s Ka-band Zenith Radar (KAZR) data quality was analyzed. Basic health checks were conducted on the KAZR to ensure all variables were operating as expected and catch any issues. A significant detection mask using only data from the radar was then developed to isolate meteorological returns. Using the significant detection mask, reflectivity comparisons between the various operational modes of the KAZR were conducted to ensure the data is well calibrated and to monitor how the offsets change over time. A cross-instrument reflectivity comparison was done using the Ka- and W-band Scanning ARM Cloud Radars (KASACR, WSACR) vertically pointing modes to check calibrations of both the SACRs and the KAZR over time. Any drastic changes in the reflectivity offsets would point to an engineering change or an issue developing. In addition to the comparisons, potential improvements to the radar were also considered. The ARM KAZR radars use pulse compression to improve sensitivity by transmitting a longer pulse. During transmission of the pulse, the radar is unable to receive data and this causes a blind range in the data. Using a year of ceilometer data, the cloud base was calculated to determine an acceptable blind range for the radar that maximized the compression gain. The methods developed for the ENA KAZR will then be applied to the Oliktok (OLI) KAZR on the north slope of Alaska. This study will show the methodology developed at the ARM ENA site for the KAZR, as well as results from the comparisons and blind range analysis at both ENA and OLI.