A climate shift in seasonal values of meteorological and hydrological parameters for Northeastern Asia

The well-known climate shift that occurred around 1976/1977 in the marine e cosystem of North Pacific Ocean was preceded by changes in the early 1970s over Northeastern Asia. In this paper long-term variability of Siberian Hig h and Aleutian Low parameters, seasonal discharge of Siberian rivers and ai r temperature and precipitation regime in their watersheds are examined in data sets covering 1945-1995. It was found that the change in seasonal valu es of Siberian river discharges is a consequence of an atmospheric climatic shift that occurred in the early 1970s over North Asia. This shift was ind uced by a change in atmospheric circulation pattern in the Eurasian sector and Pacific sector of the Northern Hemisphere after 1970. It resulted in ch anges in position and intensity of the Siberian High and Aleutian Low befor e and after the 1970s, which induced a different pattern of precipitation i n West and East Siberia. There was an increase in winter precipitation over West Siberia but a decrease over East Siberia. The period after 1970s is c haracterized by higher amplitude of all parameters and increases in the yea r-to-year variability, (C) 2000 Elsevier Science Ltd. All rights reserved.