Changes in snow cover characteristics over Northern Eurasia since 1966

Abstract

Current snow state descriptions and estimates of major snow characteristics (snow cover duration, maximum winter snow depth, snow water equivalent) up to 2010 have been recorded from 958 meteorological stations in Russia. Apart from the description of long-term averages of snow characteristics, the estimates of their change that are averaged over quasi-homogeneous climatic regions are derived and regional differences in the change of snow characteristics are studied. In recent decades, the Russian territory has experienced an increase in snow depth, both winter average and maximum snow depths, against the background of global temperature rise and sea ice reduction in the northern hemisphere. The first generalized regional characteristics of maximum snow water equivalent in the winter season have been obtained. According to field observations, an increase in water supply has been revealed in the north of the East European Plain, in the western part by 4.5% (10 yr) −1 and in the eastern part by 6% (10 yr) −1 . This characteristic also increases by ∼6% (10 yr) −1 in the southern forest zone of Western Siberia and in the Far East. Snow water equivalent in central Eastern Siberia increases by 3.4% (10 yr) −1 . From snow course observations in the forest, a tendency for a decrease in water supply (−6.4% (10 yr) −1 is only found in the southwest of the East European Plain. Snow cover characteristics, being a product of several climate-forming factors that simultaneously affected them, change nonlinearly and different characteristics may and often do change differently with time. Therefore, one cannot assume that having information about the trend of one of the snow characteristics implies knowledge of the trend sign of others. In particular, whilst during the past four decades over the Russian Federation most snow cover characteristics-including the most important of them responsible for water supply-have increased, the only quantity that is reliably monitored from space (snow cover extent) has decreased, but in the last two decades this decrease has ceased. These tendencies are opposite to those observed in Canada and Alaska.

Recent Change—Terrestrial Cryosphere

“…The greatest decreases occurred in areas where the seasonal mean air temperature was between −5 and +5°C (i.e., the mid-latitudinal coastal regions of the continents). Choi et al (2010) Bulygina et al (2011). They found a decrease in SCD since 1966.…”

“…More recently, a fast decrease in spring SCE In Fennoscandia, there has been a decreasing trend in SCE especially since the 1970s, but with some regional exceptions (Venäläinen et al 2009). SCE decreased in the Russian part of the Baltic Sea basin during the 1970-1990s; this decrease has since ceased (Bulygina et al 2011). …”

“…However, maximum winter snow depth decreased in western European Russia. An increase in SWE was seen in many areas, but decreased in western European Russia (Bulygina et al 2011). -term (1936-2008) and recent (1979-2006) trends in monthly observations on anomalies of air temperature (T), precipitation (Pr), snow depth (H) and snow water equivalent (S) for the Russian part of the Baltic Sea drainage basin (ROSHYDROMET 2008; adopted from Kitaev et al 2007Kitaev et al , 2010 In Sweden (northern part of the Baltic Sea drainage basin), maximum snow depth did not change significantly There has been a general decrease in snow depth at the majority of monitoring stations since 1914 in Norway.…”

“…According to IN-TAS-SCCONE, snow depth is still increasing despite the recent rise in global temperature, for the majority of northern Eurasia (Heino et al 2006;Kitaev et al 2010). Drozdov et al (2010) reported a slight positive trend in snow accumulation in European Russia (eastern part of the Baltic Sea drainage basin), and Bulygina et al (2011) reported an increase in mean winter and maximum snow depth across most of the Russian land area over the past four decades. In most areas, the number of days when snow depth is greater than 20 cm also increased.…”

Observed cold season changes in a Fennoscandian fell area over the past three decades

“…Long-term observational data have shown the decreases in snow cover duration in Eurasia since the 1980s and in North America since the 1950s . Changes in snow characteristics in the Northern Hemisphere show strong geographical variations, as for example, decreasing snow depths have been reported in Canada and Alaska and increasing snow depths in northern Eurasia (Brown and Robinson 2011;Bulygina et al 2011;Callaghan et al 2011;Cohen et al 2012).…”