Spatial and Altitudinal Regular Patterns of the Mean Multiannual Values of Snowmelt Flood Beginning at Watercourses of the Belaya River Basin

Abstract

The research was conducted in order to clarify the spatial and altitudinal regularities of the spring flood onset dates, taking into account the recent years of observations at 73 hydrological stations in the Belaya River basin. To analyze arrays of time characteristics, an algorithm for converting dates into the numeric format was applied. The analysis of spatial regularities was carried out using the tools of the software package ArcGIS 10.3, while the altitudinal regular patterns were identified using the method of linear trends. The work performed has resulted in identifying a number of regular patterns and drawing a schematic map of the mean multi-annual dates of the spring flood beginning. It is revealed that the spatial patterns within the territory manifest themselves via a shift to later dates for the beginning of floods while moving from the south to the north and from the west to the east. The displacement intensity amounts to 9 days for the latitudinal component, and reaches 5 days for the sectoral component. The identified latitudinal-sectoral regularities are contravened due to the relief impact; in the southwestern part of the basin, within the spurs of ObshchySyrt, while in the eastern part of the basin within the mountain structures of the Urals a shift towards the later dates was detected, and it is revealed that the center of the mountainous zone features a pronounced anomaly in the snowmelt flood beginning dates, 5-8 days in length. The results obtained can be used both for determining the mean multiannual dates of snowmelt flood beginning and for establishing predictive models. The results obtained are in line with the materials already published on the research topic and do not contradict the general ideas related to the process of spring flood formation. The presented schematic map can be applied for preliminary calculations of the mean multi-annual dates of the spring flood onset.