北极Svalbard地区冰川物质平衡研究进展

回顾了Svalbard地区冰川物质平衡观测研究的历史,总结了该区域自1950年代以来冰川物质平衡的主要特征.结果表明:1)冰川净平衡、冬季积累和夏季消融没有明显长期变化趋势,净平衡一般为负值,导致冰体不断地缩减;2)冰川冬季积累年际波动较小,基本保持稳定状态;夏季消融年际波动较大,但没有融化增加的迹象;3)面积/海拔高度分布的不同导致了各冰川物质平衡的差异,面积较小(<10 km²)、海拔较低(<500 m)的冰川持续退缩;而具有更高海拔高度、更大面积的冰川则处于平衡或略微增长状态;4)净平衡与冰川平衡线高度(ELA)具有良好的负相关性,平均物质平衡梯度无明显变化,物质平衡对平衡线高度变化(气候变化)的敏感性保持稳定;5)Svalbard地区冰川物质平衡与该区夏季各月正积温和冬季降水具有密切的相关性.最后提出了加强Svalbard地区冰川物质平衡内补给过程研究以及与我国天山冰川物质平衡的对比研究,以求更加准确地认识Svalbard地区冰川物质平衡特征.

Progress in Studies on Mass Balance of Glaciers, Svalbard, Arctic

The history of mass balance observations and studies of glaciers in Svalbard has been reviewed in this paper.Their characteristics since the 1950s are summarized as follows: 1) There is no obvious long-term tendency in annual net balance,winter accumulation and summer ablation.The annual net balance is generally negative,resulting in continuous shrinkage of glacier volumes.2) The inter-annual variation of winter accumulation is comparatively stable,while the summer ablation shows a larger inter-annual oscillation.There is no indication of increasing melting during the observation period.3) The area/altitude distribution results in the diversity of mass balance of glaciers.The glaciers with smaller area(<10 km2) and lower altitude(<500 m) retreat steadily,however, the glacier with larger area and higher elevation is kept in zero net balance or a slightly positive net balance.4) There is a good inverse relationship between net mass balance and equilibrium line altitude(ELA).No obvious change of mean mass balance gradient has been found,which means that glacial sensitivity of mass balance to ELA(or climatic) change keeps stable in Svalbard.5) Glacier mass balance in Svalbard has close relationship with positive degree-days in July,August and September-October,as well as winter precipitation.At last,in this paper,it is suggested to further strengthen the research of internal accumulation processes for polythermal glaciers in Svalbard and to study comparatively the mass balance between Svalbard archipelago and Tianshan Mountains,in order to understand the characteristics of mass balance of Svalbard glaciers accurately.