Exploiting commercial Cell Phone Links to measure Precipitation in Southern Germany

Over the last decade, wireless communication networks have grown to cover huge areas by dense meshes and, being impaired by precipitation, may therefore be considered as large-scale, high resolution atmospheric observation networks with practically no additional maintenance cost. The principal feasibility of rainfall estimation by microwave attenuation between commercial radio links (the so-called backhaul links) has been shown in Israel by Messer et al. (Science, 2006, 312: 713-714). While highly interesting in order to bridge the gap between pointwise direct gauge measurement and areal indirect radar measurement with their well-known respective drawbacks, this technique depends heavily on the density, homogeneity, and operation conditions of the mobile phone networks.

The PROCEMA Virtual Institute ("regional PRecipitation Observation by CEllular network Microwave Attenuation and application to water resources management"), sponsored by the Helmholtz Society, is dedicated to a three-year feasibility study in order to test the concept under the specific orographic, technical, and economic conditions in southern Germany. (A similar test site is situated in the upper Jordan catchment in Israel.) It is the primary goal of this project to exploit existing commercial infrastructure, including DWD's weather radar network, to produce areal precipitation maps.

As a scientific base, emphasis is given to - the collection and homogenization of commercial link data in prealpine Southern Germany - the deployment of a dedicated fully coherent and fully "polarized" monostatic experimental link - the collection and evaluation of data of the close-by dualpol C-band weather radar and X-band rain scanner - the modelling of phase and polarization effects of precipitation falling through a microwave beam - the joint evaluation of radar, link attenuation, and gauge data by the novel "copula method" - the integration of point, line, and volume measurements into a combined areal precipitation product.

The current state of the project will be presented.