The influence of atmospheric precipitation on the formation of the flow of the Zolota Lypa River during 1945-2015

Abstract

The article describes the main natural conditions and factors of runoff formation in the Zolota Lypa river basin. An analysis of existing studies of river flow was carried out. The experience of measuring the main characteristics of atmospheric precipitation and methods of river flow analysis are analyzed. The trend of air temperature changes during the observation period from 1945 to 2015 was determined and analyzed. The regime of atmospheric precipitation within the basin of the Zolota Lypa River was studied. Long-term changes and intra-annual distribution of atmospheric precipitation, in particular rain, were analyzed, and based on the data of observations of the Berezhany weather station. Periods of atmospheric precipitation fluctuations relative to the standard norm were identified and the influence of atmospheric precipitation on the formation of runoff was determined. The graph of the dependence of the flow of the Zolota Lypa River on atmospheric precipitation showed a fairly clear dependence between the variable values of the flow and atmospheric precipitation. Research of precipitation, water balance of river basins, and the impact of precipitation on river runoff remain relevant in the context of global and regional climate change. Nowadays, many scientific researches all over the world are devoted to the research of the problem of river runoff change under the influence of climatic factors. This kind of research has been developing strongly in Ukraine in recent decades. The basin of the river Zolota Lypa has a temperate-continental climate with mild summers, mild winters and sufficient rainfall. This area is flat, there are no high mountains. That is why during the year it is under the influence of cyclones that form over the Atlantic Ocean and arctic air masses that come in the form of high pressure cores. The average annual runoff is characterized by rather complex patterns of change both in time and space. There are periodic, cyclical and unidirectional changes that occur under the influence of a complex system of factors. Climate is a major factor of the water change. To determine the effect of precipitation on river runoff, the method of comparing difference-integral curves of annual runoff and precipitation, as well as water-balance methods are used. Long-term changes and intra-annual distribution of precipitation, in particular rainfall, according to the observations of the meteorological station Berezhany were analyzed. We constructed a differential integrated curve of modular coefficients of the average annual precipitation. It clearly reflects the cyclical changes in precipitation. Long-term changes and intra-annual distribution of water runoff in the Zolota Lypa River also were analyzed. During the observation period, periods of long-term fluctuations of the average annual precipitation were revealed. The average annual rainfall is 631,8 mm. The annual course is stable, in the greatest amount of precipitation falls in the summer, when there are intense thunderstorms and showers, the least – in winter. For the analysis of the water regime of the Zolota Lypa River, observation data from two hydrological stations (Berezhany and Zadariv) were used. According to the graph of the dependence of the flow of the Zolota Lypa River on precipitation for the studied period, a fairly clear connection between the variable values of the flow and precipitation can be traced. To assess the closeness of the relationship between the amount of precipitation and water consumption, a correlation coefficient of 0.74 was calculated, which is a positive approximation. In this case (with a close connection), it can be asserted that the flow of the main watercourses within the basin of the Zolota Lypa River is directly dependent on the amount of precipitation. Keywords: atmospheric precipitation, river runoff, standard climate norm, difference integral curve, correlation coefficien.