Radar Quality Index (RQI) - a combined measure for beam blockage and VPR effects in a national network

摘要

The next-generation multi-sensor quantitative precipitation estimation (QPE), or "Q2", is an experimental hydrometeorological system that integrates data from radar, raingauge, and atmospheric models and generates high-resolution precipitation products on a national scale in real-time. The quality of the Q2 radar QPE varies in space and in time due to a number of factors, which include: (1) errors in measuring radar reflectivity; (2) segregation of precipitation and non-precipitation echoes; (3) uncertainties in Z-R relationships; and (4) variability in the vertical profile of reflectivity (VPR). In the current study, a Radar QPE Quality Index (RQI) field is developed to present the radar QPE uncertainty associated with VPRs. The RQI field accounts for radar beam sampling characteristics (blockage, beam height and width) and their relationships with respect to the freezing level. A national RQI map is generated by mosaicking single radar RQI fields. The radar quality information is useful to hydrological users and can add value in radar rainfall applications.