Acta Geographica Sinica ›› 2011, Vol. 66 ›› Issue (9): 1191-1199.doi: 10.11821/xb201109004

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Variation of 0 ℃ Isotherm Height and Ground Temperature in Summer in Northwest China during the Past 50 Years

HUANG Xiaoyan, ZHANG Mingjun, WANG Shengjie, LI Yaju, PAN Shukun   

  1. Geography and Environment College, Northwest Normal University, Lanzhou 730070, China
  • Received:2011-04-15 Revised:2011-07-05 Online:2011-09-20 Published:2011-09-20
  • Supported by:

    The Program for New Century Excellent Talents in Universities by the Education Ministry of China, No. NCET-10-0019; National Natural Science Foundation of China, No.41161012; The Foundation for Young Innovative Scientists in Gansu Province; The Knowledge and Technological Innovation Project of Northwest Normal University, No.NWNU-KJCXGC-03-66

Abstract: Based on the data of 112 meteorological stations and 21 aerological stations in Northwest China from 1960 to 2009, the variation of 0 ℃ isotherm height and mean temperature in summer was analyzed. The result indicated that the mean height of 0 ℃ isotherm in summer was 4675.7 m during 1960-2009, with an annual decrease of 5.6 m before 1987 and an annual increase of 2.6 m after 1987. The ground temperature showed a similar annual trend at the 0 ℃ isotherm height, which was converse around the climatic mutation in Northwest China, with a considerable increase rate of 0.53 ℃ per decade after 1987. During 1960-2009, in most parts of Northwest China, the 0 ℃ isotherm height at Beijing Time 8:00 in summer increased significantly, and the height at Beijing Time 20:00 decreased. However, during 1987-2009, the 0 ℃ isotherm height in most parts of Northwest China increased at Beijing Time 8:00 and 20:00. A marked increasing trend of mean temperature in summer was observed in most parts of Northwest China, but the trend was opposite in Urumqi and Qinling-Daba Mountains. For the different climatic zones, the main trend and correlation between 0 ℃ isotherm height and mean temperature in summer varied spatially. The correlation was significant in the Cold Region on the Qinghai-Tibet Plateau, less significant in the Arid Region in Northwest China, and not significant in Monsoon Region in eastern China.

Key words: Northwest China, 0 ℃ isotherm height, mean temperature, climatic change