Study Again on Qinghai-Tibet Plateau Tundra:Determination of Geography Polarity for the Third Pole of Earth

Whether if there is tundra in Qinghai-Tibet Plateau,is very important for the problem that whether or not the third pole of earth(high pole)is geographic,so that it is a basic problem for global geographical science.The definition of tundra was proposed,and the index assembly of tundra environment composed by five factors was put forward.The five factors include that the mean temperature in July is 0 ℃-10 ℃;there is periglacial environment located in ice cover or glaciers periphery,and frost is strong;there is permafrost;soil is frost;it is treeless.The region with average temperature of 0 ℃-10 ℃in July is about 50.4% (129.64×104 km2)of QinghaiTibet Plateau;distribution of valley glacier is wide,and modern periglacial environment is typical in the region;the area of permafrost in the region is 72.05% of that in Qinghai-Tibet Plateau,soil is frost and tundra soil develops;it is treeless because altitude is high than forest line,but there are small brush,grass,moss and so on;therefore,there is tundra in Qinghai-Tibet Plateau.A lot of plants in marsh are special,frost peat mound is wide and is combined with cellular soil,so that marsh tundra develops.Hill tundra develops in the mountain around Qinghai-Tibet Plateau,and plateau tundra develops in the middle.The characteristic of QinghaiTibet Plateau is highland,so that there is highland tundra only in the plateau,showing the diversity of tundra.It is incorrect that there is no tundra in China except Changbai,Altai and Tianshan Mountains,but Qinghai-Tibet Plateau is the southern edge for tundra in China.The discovery of tundra in Qinghai-Tibet Plateau can confirm the geography polarity of the third pole in earth,and has important significance for understanding plateau environment deeply.