LONG-TERM FORECASTING OF THE START DATE OF SPRING FLOOD IN THE UPPER OF THE SOUTHERN BUH RIVER BY TELECONNECTION INDICES

Abstract

The start date of spring flood is an important hydrological characteristic. Insufficient attention is paid to its long-term forecasting, which is due to the complexity and unsolved problem in terms of improving the quality of such forecasting. Most often, quantitative methods are used in long-term forecasting. The most used are statistical, correlation, and regression analysis. Recently, teleconnection indices and patterns are increasingly used in hydrological long-term forecasting. At the same time, the basis of the concept of forecasting by the teleconnection connections is the idea of the influence of distant fluctuations of atmospheric circulation on the hydrological event. So, the theteleconnection indices and patterns are used for forecasting and analysis of river flow, atmospheric precipitation, research of snow water equivalent of river basins, forecasting of droughts and ice phenomena. The objective of this of the study is to develop a methodology of the long-term forecast of the spring flood start date in the upper part of the Southern Buh River using teleconnection indices and patterns. The method of long-term forecasting of the start date of spring flood was developed for the Southern Buh River – Lelitka village water gauge. The Southern Buh River – Lelitka village water gauge is located in the forest zone and characterizes homogeneous conditions of the formation of spring flood. Information on the start dates of spring flood for the observation period 1966-2015 and teleconnection indices and patterns were used. The start dates of spring flood at the Southern Buh River near Lelitka village are characterized by significant variability. So, the difference between late and early dates of spring flood is 65 days. 34 teleconnection indices and patterns were used, which the National Oceanic & Atmospheric Administration USA were determined. The best regression relationship with the start dates of spring flood at the South Buh River – Lelitka village water gauge was obtained for the indices WPAC850 in January and AAO in December. The technique corresponds to the “satisfactory” category for the probability of not exceeding the permissible error, which allows it to be used for forecasting. So, the teleconnection indices and patterns can be quite successfully used in the long-term forecasting of the start date of spring flood.