Correction of radar QPE errors associated with low and partially observed bright band layers

The melting of aggregated snow/crystals often results in an enhancement of the reflectivity observed by weather radars, and this is commonly referenced as the bright band (BB). The locally high reflectivity often causes overestimation in radar quantitative precipitation estimates (QPE) if no appropriate correction is applied. When the melting layer is high, a complete bright band layer profile including top, peak, and bottom can be observed by the radar and a vertical profile of reflectivity (VPR) correction can be made to reduce the BB impact. When a melting layer is near the ground and the bottom part of the bright band cannot be observed by the radar, a VPR correction can not be made directly from radar observations. This paper presents a new VPR correction method under this situation. From high- resolution precipitation profiler data, an empirical relationship between BB peak and BB bottom is developed The empirical relationship is combined with the apparent BB peak observed by volume scan radars and the BB bottom is found. Radar QPEs are then corrected based on the estimated BB bottom. The new method is shown to be effective in reducing the radar QPE overestimation under low bright band situations.