Evaluation of NOAA/NSSL Multi-Radar Multi-Sensor Radar Echo Top Heights with the GPM Dual-Frequency Radar

The accuracy and uncertainty of radar echo top heights estimated by ground-based radars remains largely unknown despite their critical importance for applications ranging from aviation weather forecasting and severe weather diagnosis. A vast majority of research has not used any external reference for cross-comparison. The use of space-borne radar data is explored to better identify echo top heights, as the vantage point of space is more suited for the estimation of storm tops than ground-based radars and provides a unique opportunity for systematic evaluation. An investigation has been carried out across the conterminous U.S. (CONUS) by comparing the NOAA/NSSL Multi-Radar Multi-Sensor (MRMS) system to the space-based radar onboard the NASA/JAXA Global Precipitation Measurement (GPM) satellite platform. The MRMS system combines information from all ground-based radars comprising the National Weather Service’s NEXRAD network, mosaics reflectivity data onto a common 3D grid to derive a number of meteorological products including the 18-dBZ echo top heights. The systematic biases and uncertainties of the 18-dBZ MRMS echo top height relative to the GPM radar are documented. Their relation to data voids, specifically above the highest radar tilts (cone of silence), beam broadening at far ranges and radar scanning strategies are investigated.