Performance study of the radar Sun-monitoring method

The spreading of national and international weather radar networking practices has increased efforts towards the consolidation of common procedures in weather radar data quality and calibration. The Sun is regarded a well-known and worldwide available target that can be used as reference for a number of calibration purposes. Along these lines, a Sun-based, fully automatic procedure, developed at the Royal Netherlands and Finnish Meteorological Institutes, has proven effective for online monitoring of antenna alignment and receiver chain calibration and is currently operational in several national meteorological services, as recommended for example in the framework of the European EUMETNET group. Recently, the method has been adapted and implemented for the weather radar network (XRAD) of the Meteorological Service of Catalonia and one-year of data obtained from three C-band radars has been examined in detail. In the present work, built upon the previous analysis, the distributions of solar observations collected by the XRAD radars during selected time periods serve as base for a performance study of the Sun-monitoring method. The power of the solar observations and the retrieval procedure involved in the method are simulated under controlled conditions. The aim of the study is to evaluate the precision and accuracy of the estimated calibration parameters for variable measurement conditions such as number, distribution and uncertainty of the solar observations.