天山乌鲁木齐河源1号冰川对夏季0 ℃层高度变化的响应

采用1971-2000年乌鲁木齐河源1号冰川周围4个探空站逐日0 ℃层高度探测资料, 用距离倒数的加权平均得到1号冰川的夏季0 ℃层高度, 并与1号冰川观测资料进行对比, 定性与定量分析了30 a来夏季0 ℃层平均高度变化和冰川观测量的变化趋势及之间的关系. 结果表明: 1971-2000年的30 a里1号冰川夏季0 ℃层高度呈增高趋势, 1990年代呈陡升趋势, 与1号冰川的零平衡海拔高度、消融区面积、 纯物质消融量和融水径流深4个量具有很好的一致性, 为正相关;而与积累区面积、纯积累量、纯物质平衡总量、纯物质平衡值4个量反位相同步变化, 为负相关, 说明天山乌鲁木齐河源1号冰川对自由大气夏季0 ℃层高度具有非常好的响应. 随着全球变暖加剧, 天山山区对流层中下层均显著变暖, 夏季0 ℃层高度升高, 天山乌鲁木齐河源1号冰川消融加快. 1990年代夏季0 ℃层高度陡升, 进而1号冰川出现了最大的物质负平衡.

The Response of the Glacier No. 1 to the Height Change of the 0 ℃ Level in Summer at the Riverhead of the (U)rümqi River, Tianshan Mountains

Using daily observations of 0 ℃ level from four sounding stations around the Glacier No. 1 during 1971-2000, in this paper, the changing tendency of mean height of 0 ℃ level in summer and the observed glacier mass balance parameters are analyzed qualitatively and quantitatively. In addition, the relationship between them during the past 30 a is analyzed through calculating the 0 ℃ level in summer by averaging the weighted reciprocal of distance and then further contrasting it with the observations in the Glacier No. 1. It is found that, the 0 ℃ level in summer shows a increasing tendency in the 30 a, and then went up steeply from 1990, with a positively relation to the four parameters of Glacier No. 1, including the zero balance height, ablation area, pure ablation and runoff depth of metlwater, and a negative relation to accumulation area, pure accumulation, the pure mass balance total and pure mass balance. The above correlations have the significance level of 0.05, and seven of them reach above 0.01. These indicate a good response of the Glacier No. 1 to the 0 ℃ level in summer. It is concluded that, accompanying the global warming, the middle and low levels of troposphere will warm up significantly, the 0 ℃ level in summer will rise more, and the ablation of the glacier will speed up as well. The 0 ℃ level in summer will rise steeply and a maximum negative mass balance will appear in the Glacier No. 1, correspondingly.