Cold Regions in China

There are many definitions for the phrase ‘Cold Regions’, albeit it has been widely used. In China, Cold Regions should include all the permafrost area, the glacier area, and the great majority of stable seasonal snow cover area, in which the vegetation type and climate type are, to some extent, unique compared with those in the other regions. The air temperature, according to the literal meaning of ‘Cold Regions’, is the major factor to judge whether a region belongs to Cold Regions or not. In this essay, the averaged monthly air temperature data, which were derived from 4-time daily data, at the 571 stations in China, from 1961 to 1998, were used. The averaged monthly air temperature at the each 1 km grid in Alberts projection was calculated by using the regressing equation, in which altitude, Y axis and X axis in Alberts projection of the 571 stations were input and R2 was of 0.92–0.97. The results show that the Wooʹs definition and Yangʹs definition for the Cold Regions are not appropriate in China. A new definition of the Cold Regions in China should be that the averaged air temperature of the coldest month is lower than − 3.0 °C, the number of months of which the averaged air temperature is higher than 10 °C is not more than 5, and the averaged yearly temperature does not exceed 5.0 °C. The new partition by the definition is nearly in accordance with the borders of the defacto area of permafrost, seasonal stable snow cover, vegetation distribution and climate regionalization. Therefore, the area of the Cold Regions in China by the new definition is about 417.4 × 104 km2, 43.5% of the countryʹs land area.