To overcome these problems, the radar reflectivity of rain (Z) is
measured. This provides measurements in space and time,
i.e. four-dimensional data. Using the so-called, 
-
-relation,
the measured data is transferred into the desired quantity, the
precipitation at the ground (R). The --relation strongly depends
on variations of the local drop size distribution and therefore on the
precipitation type and its temporal development. Further problems
arise through measurement noise or other artefacts, like clutter
(reflections from fixed, non-meteorological targets)and anomalous
propagation or attenuation of the radar beam.
The basis of this project is, that the radar reflectivity of rain (Z)
contains sufficient information in order to significantly improve the
estimation of precipitiation at the ground (R) in comparison to
currently used --relations. One goal is, to identify the
relevant parameters of the --relation and to develop operational
methods for precipitation measurement at the ground through radar
reflectivity. Therefore a new approach is investigated, using an
objective scale-dependant analysis of existing radar volume data
together with simultaneous surface observations of rain intensity.
Secondary goals are objective structure-based clutter elimination,
efficient radar volume storage and visualization.