Integrating Microwave Link Data for Analysis of Precipitation in Complex Terrain: Theoretical Aspects and Hydrometeorological Applications (IMAP)

The IMAP project is a joint research project between partners from Germany, Israel, and Palestine. Its main objective is to develop and apply new methods for the quantification of precipitation in regions of complex terrain and thereby improve streamflow modeling and forecasts. In these methods the most important source of information about near-to-ground precipitation is fast-fading data from commercial terrestrial microwave point-to-point links. This data is gathered from a great many of microwave links on an every-munite basis. It is used as a basis for the derivation of rainfall and humidity information as well as for spatial reconstruction of rainfields from the line-integrated information that microwave links provide.

The overall scientific objectives are:

  1. To mitigate errors and to improve calibration for microwave attenuation-derived precipitation estimates
  2. To investigate the potential of microwave link data as a source of atmospheric humidity information
  3. To improve estimates of spatio-temporal rainfall distribution by developing new data integration and reconstruction methods for gauge-, radar-, and microwave link data, as well as high resolution hydrometeorological model output
  4. To setup and extend a coupled hydrometeorological model system (WRF-Hydro), that allows to account for the complex and fast precipitation-runoff processes in mountainous terrain.

The specific research tasks at TUM are:

  1. To investigate and quantify the wet antenna effect and further shortcomings of the microwave link hardware by simulation and measurement
    • Measurement of wet antenna parameters with the aid of a controlled sprinkler in the lab
    • Study the transient behavior of wet antenna attenuation
    • Evaluation of RSL measurement accuracy in MW-link RF hardware
    • Integration of findings into MW-link processing software
  2. Develop an outdoor atmospheric transmission measurement system with actual microwave link reflector antennas
    • Based on network-analyzer hardware to measure 6 frequency bands in one sweep
    • Fully polarimetric
    • Infrared camera to monitor and document the states of the antenna radomes (degree and structure of the wetting) permanently and in real time

Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Project number SI2034/1-2