Snow Cover in the Northern Hemisphere
（Dec. 2004）
Northern Hemisphere
During December, the area with snow cover was larger than average in Eurasia, and little larger in the Northern Hemisphere (Fig.1).
In the month, the number of days with snow cover (NDSC) were more than 25 in Asia and America north to 50°N, northeastern Europe, northeastern China and parts of the Tibetan Plateau. Positive NDSC anomalies were about 5~15 in northern Italy, eastern Turkey, western Kazakstan, parts of three regions of Tibetan Plateau, eastern China and eastern America, with more than 15 days above average in part of regions. Negative anomalies about –5～–10 were observed in parts of eastern Europe, parts of Mongolia, western and southeastern Tibet, and parts of central and northwestern America, with more than 10 days below average in part of regions.
Fig.1 Regional Snow Cover Anomaly Indices (Unit: 106km2) (a)Northern Hemisphere (b) Eurasia
Fig.2 Number of Days with Snow Cover (left) and Anomalies (right) in the Northern Hemisphere during Dec. 2004. (unit:day)
China
In general, areas with snow cover in China, the Tibetan Plateau, northern Xinjiang and Northeast China were larger than average in Dec. (Fig.3).
In Dec. (Fig.4), NDSC were generally more than 25 in parts of the Tibetan Plateau, northern Xinjiang, most of Northeast China. Positive NDSC anomalies above 5 were in the area around the Tianshan Mountains, the central Tibet, eastern and southern Qinghai, northern Sichuan, parts of North China, lower reaches of the Yellow River and central Northeast China, with more than 10 days above average in local regions. Meanwhile, negative anomalies about –5～–10 were observed in the western and southeastern Tibet, and western Xinjiang.
Fig. 3 Regional Snow Cover Anomaly Indices (Unit: 104km2)
(a) China (b) Tibet Plateau (c) Northern Xinjiang (d)Northeast China
Fig.4 Number of Days with Snow Cover (left) and Anomalies (right) in China during Dec. 2004.(unit:day)
Analyst: Climate System Diagnostics and Prediction Division/National Climate Center/CMA
Climatologic fields are from the 1973-2002 base period means.
