斯瓦尔巴群岛冰川学研究进展与我国北极冰川监测系统建设

北极斯瓦尔巴群岛冰川大多数属于亚极地型(sub-polar)或多热型(polythermal)。Austre Br(?)ggerbreen和Midre Lovénbreen冰川(＜10km~2)长时间系列物质平衡研究显示,自小冰期结束以来几乎所有的观测年中夏季消融比冬季积累更大,导致冰体稳定地减小；而面积更大、海拔高度更高的冰川如Kongsvegen冰川(105km~2)则更加接近稳定态的平衡。斯瓦尔巴群岛冰川流动速率一般较低,但跃动相当频繁,控制跃动型冰川空间分布的因素包括冰川长度、基底岩性和多热场。可通过冰川水文特征、钻孔温度测量和无线电回波探测获取斯瓦尔巴群岛冰川热场的信息。斯瓦尔巴群岛冰川的低流速和多热性结构对冰川上的排水系统相当重要,整个群岛淡水径流的四个主要来源分别是冰川消融、雪融化、夏季降雨和冰崩解,经验回归方法和模式方法用于计算淡水径流量。因夏季融水渗浸作用、采样分辨率低和化学成分分析有限,早期斯瓦尔巴群岛冰芯的准确定年受到严重影响,但最近的研究显示,来自斯瓦尔巴群岛冰帽的冰芯数据仍然能够提供重要的气候和环境信息。通过我国北极黄河站2005年度科学考察,我们已初步建立了Austre Lovénbreen冰川和Pedersenbreen冰川监测系统,并计划在Austre Lovénbreen冰川进行钻孔温度测量、冰川气象要素观测、冰川前缘水文观测以及冰川厚度和内部结构测量,重点开展斯瓦尔巴群岛冰川基本特征和发育条件、冰川表面能量和物质平衡、冰川波动与气候变化关系、淡水径流年际和季节性变化和气/雪/冰界面过程等方面的研究。

THE PROGRESS OF GLACIOLOGICAL STUDIES IN SVALBARD AND CHINESE CONSTRUCTION OF GLACIER MONITORING SYSTEM CLOSE TO YELLOW RIVER STATION,NY-(?)LESUND,SVALBARD

Most glaciers in Svalbard are classified as sub-polar or polythermal.Long time series of mass balance investigations on Austre Br(?)ggerbreen and Midre Lovénbreen(＜10km~2)show that summer ablation has been greater than winter accumulation nearly all observed years since the end of Little Ice Age,resulting in steady decreasing ice masses.However,those glaciers covering larger areas at higher altitudes,such as Kongsvegen(105km~2),are closer to steady- state balance than the small ones.The flow rate of Svalbard glaciers is generally low,but there exists frequent surging.Glacier length,bedrock lithology and polythermal regime are main con- trois on spatial distribution of surge-type glaciers.Information on the thermal regime of Svalbard glaciers can be obtained from their hydrological characteristics,temperature measurements in boreholes,and radio-echo sounding.The low flow velocities and the polythermal structure of the glaciers are important for drainage system on the glaciers.The four main sources for fresh- water run-off over whole archipelago are glacier ablation,snowmelt,summer rainfall and ice calving.Both empirical regression and modelling approaches could be used to calculate the a- mount of freshwater run-off.Proper dating of the early Svalbard ice cores has been hampered by a combination of melting producing ice layers,coarse sampling and limited analysis of chemical species,however,recent studies suggest that ice-core data from ice caps in Svalbard could still provide us with important climatic and environmental information.During glaciological expedi- tion around Chinese Yellow River station in 2005,the stakes for mass balance and surface flow investigations has been set up on Austre Lovénbreen and Pedersenbreen.It is planned that tem- perature measurements in boreholes,meteorological and hydrological observations,and thick- ness and internal structure soundings will be carried out on Austre Lovénbreen.The following studies of Svalbard glaciers will be conducted:main characteristics and conditions,surface en- ergy and mass balance,glacier fluctuations and its relations with climate,interannual and sea- sonal variations in freshwater run-off,and interaction processes between atmosphere,snow and ice interfaces.