1h-precipitation amount (derived from radar and measurements), Time Sequence: 1h, 01 March 2008     

This chapter presents the precipitation amounts of the last hour (derived from the DWD-radar network and from local measurements). The colours indicate the precipitation amounts according to the radar data (the corresponding legend at each picture, click upon the key-symbol, above).

The radar data enable us to get a more detailed overview of the precipitation amounts although they may exhibit some errors. One problem during approaching colder air (as it happened in this case study) is the so-called bright-band effect. Due to technical reasons, sleet and graupel/hail exhibits relatively high reflectivities in the radar images. Because the precipitation amounts are derived from the reflectivity in 1 km height we may get high precipitation amounts which are not realistic.

During the last hour, at many regions of Germany precipitation up to 10 mm/h occured (based upon radar). However, we will only concentrate upon the precipitation in relation to the cold front and the succeeding convective line.

Precipitation anounts of 15 to 20 mm/h (from radar) happened at the Dutch coast. From the surface measurements we get the information of only up to 6 mm/h.

At German-Netherlands border up to 9 mm/h were measured. Whereas in Hamburg only 4 mm/h were reported we derive from the radar up to 15 mm/h.

Over parts of North Germany more than 20 mm/h precipitation happened (dark yellow, orange pixels).

The convective line moved fast to the South. Again we see preciptiations of up to 30 mm/h (north of Hannover, where "only" 2 mm/h were measured at the surface station).

We recognise also from the radar the line orientation of higher precipitation amounts (extending from Berlin to Cologne) with precipation of partly more than 30 mm/h (highest surface measurement: 7 mm/h at Hannover).

11 and 12 mm/h were measured in Goettingen and Wernigerode (so-called Harz), respectively. In this area no radar data were available.

The precipitation band moved fast to the Southeast. There was a quite good agreement between measurements and the radar data. The highest precipation were registered in Leipzig.

The area with most intense precipitation continued moving and arrived the line "Dresden - Southwest Germany. In Dresden up to 20 mm/h precipitation can be derived from radar.

The east parts of the convective line came outside the domain of this radar product. This image reveals high amounts over South Germany. South of Wuerzburg 12 mm/h were measured. However, the radar data exhibit less (about 5 mm/h).

The most intense preciptation arrived the Danube. We see a quite good correspondence between the measurements and the radar.

The precipitation arrived at the Alps and remained rather high with up to 8 mm/h. Again, we observe a good correspondence between both methods.

The cold front hit the Alps. The surface measurements show up to 7 mm/h. The precipitation over the northern half of Germany happened in connection to showers.