CASA Radar Display in AWIPS2

Working in conjunction with NOAA Southern Region Headquarters and Raytheon, the ERC for Collaborative Adaptive Sensing of the Atmosphere (CASA) has successfully introduced functionality into AWIPS2 to process and display radar moment data and merged product data. Successful integration into the standard AWIPS2 build ensures that all National Weather Service weather forecast offices are able to display data conforming to the standards that were defined as part of this project. This paper describes the process that was undertaken for AWIPS2 integration, the format specifications and the rationale behind them, the ingest and notification process, as well as provides example imagery and recommendations to further facilitate use by the radar operators during weather events. Unlike the original CASA radar ingestion into AWIPS that was undertaken in 2010, the AWIPS2 modification was intended for the baseline distribution, such that all offices would have the necessary tools to display radar data of this type. It suggested a generalized approach rather than a very specific one tailored to existing CASA products. Future low power radar deployments may be phase steered and care was taken to avoid scan assumptions that would preclude radars of this type. NetCDF format was selected for its flexibility, self describing nature, ease of use, and compatibility with existing tools. Two formal NetCDF header types were defined, one for radar moment data in polar coordinate form, another for 3d gridded data in altitude above sea level/latitude/longitude coordinate form. We have successfully encoded and displayed moment data from mechanical and phase tilt radars, as well as gridded data representing merged reflectivity, quantitative precipitation estimation, and multi-Doppler winds. The examination of radar data in real time forecasting is highly time sensitive. A dense network of radars generates a substantial amount of data and we evaluate the throughput and notification times, representing the delay from the time the radar data is sent out from the radars to the moment that the WFO forecaster is informed of the availability of that data within their CAVE display. This involves many steps including compression/decompression, transfer to a central processing location, queueing and pattern matching, firewall passage, and recognition by the display of the arrival of the data with subsequent updating of the product tables. Finally, we have made initial observations regarding the user interface for this type of data. Certain selection criteria may not be ideal for CASA data, specifically the generalized association, and resultant menu access methods, of a single radar with a portion of the forecast area. Similarly there are some built in scan selection tools that may be confusing should a radar execute non-standard scan strategy. We have chosen to adapt the radar data to smoothly interface with the existing front end tools, with the hope that in later releases there may be a paradigm shift in scan selection and areal observation techniques when using the CASA-enabled tools provided in AWIPS2. We make recommendations for efficient use in the meantime, and future development efforts.