The precipitation-radar images show only qualitative information
on precipitation.The radar images are based on non-processed raw
data. Their quality is limited to non-quantitative information,
since radar is only an indirect method of measuring
precipitation, based on reflectivity. Quantitative information
from radar measurements is obtained by comparing the data with
conventional precipitation measurements. However, real-time
measurements aren't possible yet. This so-called quasi-
calibrated data is neither produced regularly nor updated. For
different technical reasons radar information is still
incomplete and patchy. The spatial resolution of the
precipitation radar image is 4 km x 4 km and the temporal
resolution is 15 minutes. Based on the magnitude of radar
reflection seven different intensities of precipitation were
distinguished.