ИСТИНА

Hydrological anomalies which occurred in the last decade in the Amur river basin, russian Far Eastern region that has rich natural resources, require detail research of their reasons. Total water runoff of the Amur river during warm periods depends on quantity of a precipitation. The formation of heavy precipitation and low-water summer seasons are connected with macrometeorological conditions. In the context of revealed regional climate changes over the Amur basin the atmosphere circulation conditions of extreme drought in 2008 and catastrophic flood in 2013 are analysed. The choice of these two different for weather conditions events lead to discover common connections of the meteorological processes over the Amur basin with the climate anomalies. It is revealed that the formation of heavy precipitation in the Amur river basin in june — september 2013 is associated with the series of polar-front cyclones of the unprecedented duration and intensity. The intensification of frontal rainfalls was caused by the active participation in frontal processes of very warm and moist marine tropical air from the Pacific Ocean. The simultaneous deepening of the surface Far Eastern depression and the strengthening of the subtropical high over the ocean became a reason for the dramatic intensification of the moisture-laden monsoon flow. The drought in 2008 is associated with strengthening of the high pressure area over the Amur basin, that didn't allow main source of heavy rainfall take part in the frontal processes. Correlation analysis of vertical velocity with Arctic oscillation (AO) and Pacific-North American (PNA) teleconnection patterns revealed their significant dependence.