1980—2019年藏东南帕隆藏布流域冰川物质平衡模拟

Simulation of mass balance of glaciers in the Parlung Zangbo basin in southeast Tibet from 1980 to 2019

帕隆藏布流域位于中国海洋性冰川发育最为集中的藏东南地区,近年来随着全球气候变暖,帕隆藏布流域冰川亏损显著。利用全球开放冰川模型(OGGM)模拟了1980—2019年藏东南地区帕隆藏布流域1554条冰川物质平衡,发现1980—2019年帕隆藏布流域全域冰川物质平衡呈现不断亏损的状态,为-0.41 m w.e.·a^(-1),在2000—2019年物质平衡亏损更为严重,达到-0.56 m w.e.·a^(-1)。从空间分布上来看,流域东南部和流域西北部是冰川亏损最为严重的区域,流域中部和西部冰川亏损相比较少。温度的升高和降水的轻微减少是冰川物质亏损的主要原因。通过气温和降水的敏感性分析,气温上升1℃,流域71.75%的冰川物质平衡变化在-1000~-500 mm w.e.·a^(-1);降水减少20%,62.81%的冰川物质平衡变化在-450~-300 mm w.e.·a^(-1),相较于降水,冰川对气温变化更为敏感。通过分析国家气象站及再分析数据,发现1980—2019年气象站气温上升均超过1.5℃,波密站2000—2019年总降水相较于前20年,减少了10%,流域降水整体呈现减少的趋势,气温的持续升高和降水的轻微减少导致帕隆藏布流域冰川处于持续亏损之中。

The Parlung Zangbo basin,located in the southeastern Tibetan Plateau,where the marine glaciers are most concentrated.However,due to global climate warming over recent years,these glaciers have experienced substantial losses.By applying the Open Global Glacier Model(OGGM),we simulated the mass balance of 1554 glaciers within the basin from 1980 to 2019.The results show that the mass balance of the entire Parlung Zangbo basin was in a continuous state of loss from 1980 to 2019,with a rate of-0.41 m w.e.a^(-1).The loss was even more severe in 2000—2019,reaching-0.56 m w.e.·a^(-1).Spatially,the southeast and northwest parts of the basin suffer from the most severe glacier losses,while the central and western parts have relatively less.The main causes of glacier mass loss are the increase in temperature and a slight decrease in precipitation.Through sensitivity analysis of temperature and precipitation,it was found that when the temperature rises by 1℃,the mass balance of 71.75%of the glaciers in the basin changes at a rate of-1000 to-500 mm w.e.a^(-1).When pre⁃cipitation decreases by 20%,the mass balance of 62.81%of the glaciers changes at a rate of-450 to-300 mm w.e.·a^(-1).Compared to precipitation,glaciers are more sensitive to changes in temperature.Meteorological data analysis from the National Meteorological Station and reanalysis data showed that the temperature increased by more than 1.5℃ from 1980 to 2019.Total precipitation at the Bomi Station from 2000 to 2019 was 10%lower than in the previous 20 years,and the overall precipitation in the basin showed a decreasing trend.The ongoing rise in temperature,coupled with a marginal decline in precipitation,has resulted in sustained glacier mass re⁃duction in the Parlung Zangbo basin.