Original paper
Characteristic spatial extent of hourly and daily precipitation events in Germany derived from 16 years of radar data
Lengfeld, Katharina; Winterrath, Tanja; Junghänel, Thomas; Hafer, Mario; Becker, Andreas
Meteorologische Zeitschrift Vol. 28 No. 5 (2019), p. 363 - 378
56 references
published: Dec 2, 2019
published online: Sep 20, 2019
manuscript accepted: Jun 19, 2019
manuscript revision received: May 17, 2019
manuscript revision requested: Mar 22, 2019
manuscript received: Feb 7, 2019
Open Access (paper may be downloaded free of charge)
Abstract
Precipitation is an important component of our climate system that is highly variable in space and time and, therefore, difficult to observe. Heavy rainfall events can be devastating especially in urban areas and can even lead to loss of life. In Europe, long lasting heavy rainfall can be captured by raingauge networks because it mostly occurs on scales of 100 km or more associated with frontal systems. Short-term heavy precipitation, however, is mainly caused by convective events affecting only a few 10 km or less and requires spatially contiguous observations of radar systems. A 16‑year precipitation climatology from the C‑band radar network operated by the German Weather Service allows for a comprehensive analysis of the characteristic spatial extent of daily and hourly precipitation events and their spatial patterns in Germany. Daily precipitation is clearly related to the orography with larger precipitation depths in mountainous regions, e.g. the Alps or the Harz Mountains, whereas hourly precipitation seems to be less influenced by the orography and occurs in flatlands and mountainous areas in a similar frequency and intensity. The mean characteristic spatial extent, defined as the distance where the spatial correlation function of precipitation time series from the radar climatology falls to 1∕e$1/\mathrm{e}$ of its maximum value, amounts to 215 km for daily precipitation events in Germany. For hourly precipitation it is 5.5 times smaller with 39 km. This corresponds more or less to twice the mean inter-station distance of the German rain gauge network and underlines the importance of weather radar for observing and investigating small-scale structures of heavy short-term precipitation events that cannot sufficiently be captured by rain gauges.
Keywords
radar meteorology • precipitation climatology • rainfall events • rainfall statistics • spatial extent of precipitation events