Assessment of effects on sea-level changes due to recessions of large-scale temperate glaciers caused by global warming

这项研究主要是通过分析1999年和2000年在南美洲巴塔哥尼亚冰川实地调查中获得的样本和数据进行的。冰芯钻探于1999年12月在廷德尔冰川堆积区头部(1756ma.s.l)附近进行。在实验室中对46米长冰芯沿线的稳定氧和氢同位素以及主要离子和生物量进行了分析，以估计巴塔哥尼亚冰场的积累率。1997/98-1998/99平衡年度的年净累积率估计为1780万欧元，而1998/99-1999/00年度的净累积率为110万欧元。这种高的净积累率使廷德尔冰川成为世界上最极端的海洋冰川之一。巴塔哥尼亚几乎所有的大型冰川都向西崩解成峡湾，向东崩解成湖泊。研究了湖相崩解的厄普萨拉冰川的动力学行为，发现冰川的锋面变化应受到冰床地形和纵向伸展的影响。从巴塔哥尼亚的淡水冰川获得了崩解速度与崩解末端附近的水深之间的线性关系。1999年12月，在Perito Moreno冰川末端附近进行了流速和冰解事件的测量。最大流速为2.7md^~(-1)~(-1)。根据对索勒冰川等地的水流速度和消融速率的测量，建立了动态冰川模型。

This study was conducted by analyzing mostly the samples and data obtained from the field surveys at glaciers in Patagonia, South America, made in 1999 and 2000. Ice-core drilling was carried out in December 1999 near the head(1756m a.s.l.)of the accumulation area of Tyndall Glacier. Analyses of stable oxygen and hydrogen isotopes as well as major ions and biomass along a 46-m-long ice-core were made in laboratories to estimate accumulation rates over the Patagonia Icefield. Annual net accumulation rate was estimated as 17.8m a^<-1> w.e.in the balance year of 1997/98-1998/99, whereas 11.0m a^<-1> in 1998/99-1999/00. This high net-accumulation rate ranks Tyndall Glacier as one of the more extreme maritime glaciers in the world. Almost all large-scale glaciers in Patagonia calve into fjords to the west and into lakes to the east. Dynamic behavior of the lacustrine calving Upsala Glacier was studied, and it was found that the frontal variations should be affected by the bed topography and longitudinal stretching of the glacier. A linear relationship between calving velocity and water depth near the calving terminus was derived from freshwater calving glaciers in Patagonia. Measurements of flow velocities and calving events were carried out in December 1999 near the terminus of Glaciar Perito Moreno. The largest velocity was obtained as 2.7m d^<-1> at the front tip. A dynamic glacier model was constructed on the basis of measurements of flow velocity and ablation rates at Soler Glacier and others.