Variations of Glacier Mass Balance and Their Response to Climatic Change
Ding Yongjian and Bing Hongtao(Lanzhou Institute of Glaciology and Geocryology, Chinese Academy of Sciences, 730000)
Based on the data of mass-balance which are continiously mesaured on more than 40 glaciers in the last thirty to fourty years, this parer analyses some characteristics of mass balance varations of the main glacierized areas in the northern hemisphere. Mass balance variations have not only similar features within a region, but also represent a certain connections between regions. Fluctuations of mass balance in Scandinavia, Rocky Mountains and Tianshan Mountains mostly show corresponding connection. However, compared with glaciers in the Apls, slight anti-variations seem to exist between mass balance series in the above regions and those in the Apls. This paper also discusses the suitability of relationship between mass balance and ELA in different space scales, it is found that loss of mass balance in various regions corresponds to a rise of 0.7-1.2℃ in air temperature relative to zero balance (stable state) in the last thirty to fourty years. Sensitivity of mass balance to ELA shift is associated with balance conditions: the higher the mass balance tends to the negative value, the higher the sensitivity is, and the effect of air temperature on mass balance is much more obvious than that of precipitation in the hemispherical range. Mass balance is closely related to winter air temperature in the scale of hemisphere. Sensitivity of mass balance to climatic warming is approximately-800 mm/ a per degree temperature rise, which is quite comparable with the other studies.