祁连山地区更新世以来冰期雪线变化研究

Study on Snowline and Climate Changes during Different Ice Ages in the Qilian Mountains since Pleistocene

通过统计祁连山地区5次冰期雪线下降值,以及相应的温度、降水变化的数据,反映出中更新世以来冰期气候(温度和降水)使得此区雪线不断迁升,冰川规模越来越小。并认为,太阳辐射能量的周期性变化是冰期气候变迁的根本因素,而青藏高原隆升对大气环流的改变及其对气候降温的反馈作用等是十分重要的气候影响因子。

In this paper, the degressive altitude of snowline and the corresponding change of temperature and precipitation in the Qilian Mountains during five ice ages since Pleistocene are lucubrated. The results are as follows： （ 1 ） The degressive altitude of snowline in the Qilian Mountains was decreased from the earliest ice age to the latest ice age, which reveal that the snowline altitude has been continuously increased and the glacier size has been reduced under global climate change since Pleistocene; （2） Change of snowline is closely related to the change of precipitation and temperature, for example, the degressive altitude of snowline in the mountains during the third ice age from now was the most significant because of the low temperature and more precipitation, whereas the size of glaciers during the second ice age from now did not exceed that during the third ice age from now under lower temperature but less precipitation; （3） It is considered that the periodical change of solar radiation is the main cause resulting in climate change and alternation of ice ages and interglacial ages. Moreover, the uplift of the Qinghai-Ti-betan Plateau brings about the changes the atmospheric circulation, temperature and precipitation as well as snowline, so it is also an important factor affecting climate and snowline changes.