SCIENTIA GEOGRAPHICA SINICA ›› 2012, Vol. 32 ›› Issue (12): 1513-1520.doi: 10.13249/j.cnki.sgs.2012.012.1513

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Permafrost Distribution Using Sub-region Classification and Multivariate Data in the Wenquan Area over the Qinghai-Tibet Plateau

Xiu-min ZHANG1,2(), Yu SHENG1(), Lin ZHAO3, Ji-chun WU1, Ji CHEN1, Er-ji DU3, Yan-hui YOU1   

  1. 1.State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu 73000, China
    2. Shaanxi Regional Electric Power Goup Company Limited, Xi′an, Shaanxi 710000, China
    3. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu 73000, China
  • Received:2011-09-07 Revised:2012-01-08 Online:2012-12-20 Published:2012-12-20

Abstract:

The Wenquan area is located in the southeastern part of the Qinghai-Tibet plateau. Administratively, it extends across four counties, Xinghai, Maduo, Maqin and Dulan of the Qinghai Province, western China. It is a transitional area from the seasonally frozen soil to permafrost. In order to understand distribution patterns of permafrost in the area, a comprehensive field exploration was carried out, from September to October, in 2009. Based on the methods of field exploration, as well as theoretic analysis and model building in doors and the data of digital elevation model and field, it was found that aspect has important influence on the distribution of permafrost. In this paper, sub-region classification method was proposed to deal with the distribution of permafrost because of the impact of complex terrain. For the plain area, the permafrost distribution map in Kuhai area was completed by the expert knowledge and other areas’ maps which completed by means of annual ground temperature model. For the mountain area, the effects of aspect on the distribution of permafrost were studied quantitatively and a permafrost distribution model was constructed. Taking ground temperatures of permafrost as classification principles, the distribution map of permafrost and the spatial distribution patterns analysis were carried out. The results showed that the area of permafrost was 1 681.4 km2, accounting for 66.7% of the whole area. The transitional and sub-stable permafrost were the major types of permafrost, accounting for 50.8% of the whole area; unstable permafrost was accounted for about 11.4% of the total area, yet the percentage of stable and extreme-stable were smaller relatively, the percentage was 4.4% and 0.2% respectively. From the distribution pattern of permafrost, vertical zoning characteristics were demonstrated in the distribution of permafrost, i.e., the type of frozen ground would be altered with the increase of altitude and the decrease of permafrost ground temperature. A change was that seasonal frozen ground changed into unstable permafrost, then transitional permafrost, then substable permafrost, then stable permafrost, and extremely stable permafrost eventually with the increase of elevation.

Key words: permafrost, distribution sub-region, multivariate data, Wenquan area

CLC Number: 

  • P461.4