北极Svalbard群岛Austre Lovénbreen和Pedersenbreen冰川表面运动特征

以野外实测数据为基础,分析北极Svalbard群岛Austre Lovénbreen和Pedersenbreen冰川表面运动特征。结果表明:(1)Austre Lovénbreen和Pedersenbreen冰川表面水平运动速度平均分别为2.14 m·a-1和6.28 m·a-1,变差系数平均分别为0.24和0.14,夏季水平运动速度略高于冬季,水平运动速度与其所处海拔高度具有多项式型关系,冰川主流线表面水平运动速度高于两侧,冰川两侧的表面水平运动速度不对称,Austre Lovénbreen冰川从源头至末端依次表现为运动的压缩区、拉伸区和压缩区;(2)Austre Lovénbreen和Pedersenbreen冰川表面垂直运动速度平均分别为0.76 m·a-1和0.90 m·a-1,两条冰川表面夏季垂直运动速度均大于冬季且夏季变差系数小,垂直运动速度与海拔高度具有一元线性相关性,表面物质平衡造成的高程变化对垂直运动速度的贡献率最大;(3)Austre Lovénbreen和Pedersenbreen冰川表面应变率分布表现为沿主流线方向逐渐减小然后负向增加,且其变差系数平均分别为0.19和0.15。

CHARACTERISTICS OF SURFACE MOVEMENT ON THE AUSTRE LOVéNBREEN AND PEDERSENBREEN GLACIERS,SVALBARD, THE ARCTIC

The glaciers Austre Lovénbreen and Pedersenbreen are located near Ny-?lesund, Svalbard, Arctic. The characteristics of surface movement are analyzed based on filed data from 2005 to 2011 on both glaciers. The results are as following: (1) The average horizontal velocities of Austre Lovénbreen and Pedersenbreen are 2.14 m?a-1 and 6.28 m?a-1 , respectively, and their corresponding variation coefficient are 0.24 and 0.14, respectively. The average horizontal velocity in summer of two glaciers is slightly higher than that in winter. There is a multinomial relationship between the glacial horizontal velocity and its elevation. The horizontal velocity is larger along glacial mainstream line than that on both sides, and its distribution is not symmetrical on both sides of Austre Lovénbreen glacier. Based on the glacial movement features, Austre Lovénbreen can be divided into three regions from its origin to terminal, and they are compressional region, stretching region and compressional region in order. (2)The average vertical velocities of Austre Lovénbreen and Pedersenbreen are 0.76 m?a-1 and 0.90 m?a-1 respectively, and their corresponding variation coefficient are 0.81 and 0.59, respectively. The vertical velocities are bigger in summer with a smaller variation coefficient than that in winter .There is a linear relationship between the glacial vertical velocity and its elevation. According to their contribution to the composition of vertical velocity on Austre Lovénbreen, height changes caused by surface mass balance makes the greatest part in 64%, followed by compensation flow (19%) and horizontal velocity components (16%). On Pedersenbreen, in contrast, height change caused by surface mass balance makes the greatest contribution in 40%，followed by horizontal velocity components (35%) and compensation flow (25%). (3) The surface strain rate decreases firstly and then increases along the mainstream line direction on Austre Lovénbreen and Pedersenbreen, and their corresponding average variation coefficient are 0.19 and 0.15, respectively.