Studying the Areal Rainfall Reduction in the Urals Based on Radar Data

Аннотация

The study considers problems of estimation of the areal reduction of flood-forming rainfalls based on the joint use of rain-gage and radar information for the territory of the Urals. Information on areal rainfall reduction is crucial in development of methods for calculating the flood runoff of unexplored rivers. The large volume of rain-gage records (>6000 individual showers) for the period of 1936–2015 was collected and processed as well as radar data on cloud reflectivity for the period of 2003–2015 (data of the MRL-5 pulse weather radar from the Koltsovo airport are used). Empirical dependences between precipitation intensity for short (30 minutes) time periods and reflectivity of clouds in the first surface layer (to the altitude of 1000 km) are derived for several weather stations. The stability of parameters of these dependences is assessed as moving away from the radar. Based on these dependences, we determined the areas of territory irrigation by precipitation of various intensity and the parameters of the areal rainfall reduction. Taking into account the previous studies, the “double-reduction” dependence of rainfall intensity on its time and irrigated area is developed. Preliminary calculations of precipitation intensity depending on time and irrigated area are performed for Yekaterinburg weather station.