Winter snow anomaly and atmospheric circulation in Mongolia

Abstract

An observational study was conducted of winter snow anomaly in Mongolia and the associated atmospheric circulation. Monthly data of snow depth and temperature at 23 Mongolian stations from 1940 to 1992 were used for a statistical analysis. The Mongolian snow amount is fairly large in the northern mountainous regions and decreases to the south. On average, there is a substantial seasonal increase in snow depth during November and December. The deepest snow occurs in January, with an average depth of 3.4 cm averaged for all 23 stations. The correlation coefficients for November and December between the snow depth and temperature are significant and negative over wide areas.A principal component analysis was applied to interannual anomalies of January snow depth. The first mode (PC1) reveals widespread loadings of the same sign, and the second mode (PC2) shows a northeast-southwest dipole pattern. A correlation analysis was employed to examine relationships between PC1, PC2 and the preceding atmospheric circulation modes derived from a principal component analysis of the Northern Hemisphere 500 hPa geopotential heights. The PC1 time series for January is highly correlated with the North Atlantic oscillation for November, and the PC2 time series is significantly correlated with the Eurasian pattern for December. These relationships will provide a potential basis for long-range forecasts of mid-winter anomalous snow that leads to a significant loss of livestock (so-called white dzud ) in Mongolia.

Role of atmospheric circulation with respect to the interannual variability in the date of snow cover disappearance over northern latitudes between 1988 and 2003

“…Morinaga et al [2003] found a significant and negative correlation between snow depth and the EA/WR pattern in January (R = À0.47). Ye [2001b] analyzed the interannual variability of the winter snow accumulation in northern Eurasia between 1936 and 1995 using rotated PCA and showed a snowpack pattern representative of central Siberia and western Russia, which is connected to the EA/WR pattern.…”

“…[7] Several studies have investigated the links between atmospheric circulation patterns and snow cover and, in some cases, found significant relationships that would be useful for seasonal forecasting [e.g., Saunders et al, 2003;Gutzler and Rosen, 1992;Clark et al, 1999;Morinaga et al, 2003;Bamzai, 2003].…”

Habitat Fragmentation by Railways as a Barrier to Great Migrations of Ungulates in Mongolia

“…Annual average precipitation in this area is less than about 350 mm, but its interannual variation is large (Vandandorj et al 2015;Yu et al 2004), which is typical for drylands. Because precipitation and snowfall increase and temperature decreases from south to north (Morinaga et al 2003;Nandintsetseg and Shinoda 2011), vegetation correspondingly changes from desert to drylands and forest steppe ecosystems. Droughts and severe winters are a cause of high mortality among livestock (Fernandez-Gimenez et al 2012Tachiiri and Shinoda 2012) and wild animals (Kaczensky et al 2011a).…”

The effects of ocean SST dipole on Mongolian summer rainfall

“…The annual mean temperature is approximately -4 °C in the high mountains, 2 °C in the steppe and desert steppe zones, and 6 °C in the desert regions. Snowfall occurs between mid-October and the end of April, and the annual maximum snow depth (34 mm) occurs in January (Morinaga et al, 2003). The growing season (from May to August) in Mongolia is very short.…”