The Lower Amur River Hydrological Regime and Relations Between the Summer-Autumn Runoff and Circulation Indices

Abstract

Long-term forecasting of flood flow in the lower reaches of the Amur is an urgent task of modern hydrometeorology serving the needs of economic sectors. The article analyzes the dependences between the runoff volumes in three sections of the Lower Amur and the amount of precipitation (at 10 representative weather stations for the period 1950−2015) as well as atmospheric circulation indices (9 climatic and 8 regional) at the 95% significance level. Considerable attention is paid to the search for predictors of the flood runoff formation (summer-autumn period). For this, the hydrological regime and flow dynamics in the sections of the lower part of the Amur basin (from 1897 to 2018) are considered. Based on the correlation matrices, the effect of atmospheric circulation and precipitation on the river runoff is analyzed. An assessment of the long-term dynamics of runoff volumes showed a decrease in both annual water content and water content in the warm period of the year against the background of a negative trend of precipitation. For regional indices (compared with climatic ones), the largest number of significant asynchronous relationships between the runoff volume and the state of atmospheric circulation was obtained with a lead time of 1 to 5 months. The results of the study will be further used to develop equations for long-term forecasting of flood flow.