Quasi-Biennial and Quasi-Decadal Variations in Snow Accumulation over Northern Eurasia and Their Connections to the Atlantic and Pacific Oceans

Abstract

Spatial and temporal characteristics of winter snow depth variation over northern Eurasia and their connections to sea surface temperatures (SSTs) and associated atmospheric circulation anomalies, surface air temperatures, and precipitation are examined by using 60 yr (1936?95) of station data records. This study found that snow depth variation over the region east of the Caspian Sea and west of China, explaining 10.1% of total snow depth variance, has a quasi-biennial variability of about 2.5 yr. The snow depth variation over central European Russia and western-central Siberia, explaining 8.1% of the total snow depth variance, has a quasi-decadal variability of about 11.8 yr. The snow depth variation over the northern Ural Mountains, explaining 7.5% of the total snow depth variance has, variability of about 8 and 14 yr. The quasi-biennial snow depth variation is associated with SSTs over the northern North Pacific and tropical western Atlantic extending into the Gulf of Mexico. The associated atmospheric circulation pattern of Eurasia 1 (EU-1) and the Pacific?North American (PNA) pattern determine the surface air temperature conditions and thus snow depth at the biennial timescale. The quasi-decadal snow variation is associated with a well-known SST anomaly pattern over the Atlantic, having opposite SST variations in alternating latitudinal belts, and SSTs over the tropical Pacific Ocean. The associated atmospheric North Atlantic oscillation (NAO) and the circulation anomaly over central Siberia affect both surface air temperature and precipitation and thus snow depth anomaly on this quasi-decadal timescale. The results provide observational evidence of possible causes for snow depth variability over high-latitude regions.