Using operational weather radar to assess high-resolution numerical weather prediction over the British Isles for a cold air outbreak case-study



Examination of weather radar data from the Constrain field campaign during January 2010 is presented, and comparisons between the radar data and reflectivity data computed from the Met Office high-resolution British Isles NWP model (UKV Δx = 1.5 km) are shown. Cluster analysis was used to identify and track cells of precipitation in the two datasets; this allowed characteristics of the cloud field to be examined. Cells of precipitation were identified in the data using a reflectivity threshold of 10 dBz which allowed these cells to be tracked as they moved through the region of interest. The mean cell area identified in the radar data was found to be 37.5±1.3 km2, while the mean area of cells identified in the model data was 63.5±2.0 km2. Significant differences between the model and radar data were seen in the shape of the cells, with the cells identified in the model found to be more circular than those seen in the radar data.