GEOGRAPHICAL RESEARCH ›› 2006, Vol. 25 ›› Issue (1): 35-42.doi: 10.11821/yj2006010005

• Earth Surface Processes • Previous Articles     Next Articles

Investigation on changes of snow cover and climate in Helanshan mountains for the past approximate millennium

QU Xiang-ning, WANG Yi-ming   

  1. Western China Ecology Research Center,Department of Geography,Ningxia University,Yinchuan 750021,China
  • Received:2005-01-08 Revised:2005-09-26 Online:2006-02-15 Published:2006-02-15

Abstract:

For the past approximate millennium, the general changing trend in climate is warmer due to the snow fall in summer and winter and snow cover for the whole year in the Western Xia regime,the snow cover for the whole year in the Ming Dynasty,and snow cover without snow fall in the summer of the early Qing Dynasty according to the historic snow cover record of the Helanshan mountains.Also it is confirmed that the period from the Western Xia regime to the Yuan and Ming dynasties witnessed cold climate,and the characteristics of the snow cover reflected climate change agreed well with the characteristics of the climate change in western China.It is found that the time change process and the change regularity are of agreement,and the inference for the minimum limit of permanent snow cover of the cold stage in the 12th century was given by comparing historic snow cover changes of Halanshan,Tianshan,Taibaishan and Diancangshan mountains. Helanshan recorded the climate change in a specific stage.In the warm stage of the Middle ages,Helanshan presented the characteristic cold and cool climate of the western China,and gave an evidence of the existence of the cold stage in the 12th century by the snow cover and the other environmental record.It showed the characteristic of both cold and wet,and the decline of snow line.The Little Ice Age was also reflected in the record of the Helanshan mountains,i.e.,it was cold and dry with decreasing in snow line. According to the relationship between the number of the annual lowest temperature(≤0℃) days and the annual mean temperature of the Helanshan Observatory and taking into the consideration of the change in temperature in the specific stage,the inferences that annual mean temperature of the cold stage in Helenshan in the 12th century was predicted to be 1.52℃ lower than the present, and the lower limit of the permanent snow cover was estimated to be 3400 to 3500m;the annual mean temperature of the Little Ice Age in the 17th century was 11.5℃ lower than that of the present and the lower limit of the permanent snow cover decreased to 3400 to 3500m were also given.

Key words: Helanshan mountains, permanent snow cover, climate change, cold stage