A Revised Potential Extent of Desertification in China

Based on the definition of desertification from the United Nations Convention to Combat Desertification,the potential extent of desertification in China was revised by employing Thornthweite's and Penman's formulae to calculate humidity index using the records of 671 meteorological stations from 1950 to 1990,and the biogeographical features of the climate types were clarified.The calculated result was adjusted according to the climate division and vegetation division of China and the characteristics of desertification development of China.The results show that: ①The potential extent of desertification and the criteria for climate division defined by the United Nations Convention to Combat Desertification are not applicable to all cases in China.②Desertification occurs in extremely arid,arid,semi-arid and sub-humid areas in China.The extremely arid area corresponds to extremely arid desert,the arid area corresponds to desert,steppe desert and desert steppe,the semi-arid area corresponds to steppe and the sub-humid area corresponds to the drier part of meadow steppe.③The revised potential extent of desertification in China is about 4524089.1 km2,accounts for about 47.1% of the total terrestrial area of China,in which,sub-humid,semi-arid,arid and extremely arid areas account for 12.6%,28.8%,34.4% and 24.2% respectively.The potential extent of desertification increased 1207056.9 km2 compared to the former results after revision,sub-humid area decreased,semi-arid,arid and extremely arid areas increased.