An operational methodology to control radar measurements stability from mountain returns

Radar measurements can suffer from lack of stability due to different causes, especially in the case of attenuated radars. From electronic fluctuations to general attenuation due to rainfall over the radome, this kind of under-detection could become critical in some cases. It also may lead to improper application of other usual correction procedures (as correction of screening effects from partial blocking, or rainfall attenuation) if signal stability is not controlled and corrected. A methodology to monitor and control the stability of radar measurements based on the analysis of the mountain returns is proposed. It has been designed to work operationally on real time, and it is has two objectives: 1) to give a real-time alert in case of big signal instabilities and 2) to estimate a correction factor. The methodology identifies and compares the present ground clutter map with a climatological mean one, obtained avoiding anaprop situations. It takes into account in a simplified way the effects of eventual rain over the mountains and on the travel path. Some selected case studies from its operational application at the CMTC (Instituto Nacional de Meteorologia, Barcelona) are used to illustrate and evaluate the proposed algorithm.