New insights into the wet antenna attenuation effect based on data from a dedicated field experiment with CML antennas

The monostatic field experiment ATTRRA2 uses six dual-polarized, customary CML antennas which operate at different frequency bands. The experiment is installed at the TERENO field site in Fendt, Germany. A mounted camera provides pictures of the antenna radomes, and, thereby, visual information about the wetness distribution on the antennas. On-site disdrometers provide a reference for the rainfall intensity. Transmit-receive signal level (TRSL) data commonly used for quantitative precipitation estimation (QPE) is recorded into a minutely sampled time series together with the so-called antenna mismatch factor. The latter provides additional information about the radome condition in this use case and, thereby, serves as a proxy measurement of the wet antenna attenuation (WAA). Careful analysis of the data yields new insights into the temporal dynamics of WAA, especially during dewy periods before actual rain and drying periods after rain events. A comparison with established WAA correction methods shows that the proposed one performs promisingly, especially during periods of high TRSL fluctuations. A remaining challenge is the long-term stability of the instrument which will be specifically addressed in the future.