基于冰川动力学的古里雅冰帽稳定态建模分析  

An analysis of the ice temperature and velocity along the main flowline of Guliya Ice Cap of Western Kunlun Mountains based on glacier dynamical model

作　　者：陈万宝 刘时银 李维德[1] 王伟利 王荣军 

机构地区：[1]兰州大学数学与统计学院,兰州730000 [2]云南大学国际河流与生态安全研究院,昆明650091 [3]中国科学院西北生态环境资源研究院冰冻圈科学国家重点实验室,兰州730000 [4]SGT Inc,NASA Goddard Space Flight Center [5]中国科学院大学,北京100049

出　　处：《科学通报》2017年第33期3910-3920,共11页Chinese Science Bulletin

基　　金：科技部科技基础性工作专项(2013FY111400);中国科学院重点部署项目(KZZD-EW-12-1);国家自然科学基金(41571016);云南大学人才引进项目(YJRC3201702)资助

摘　　要：古里雅冰帽是已知亚州中部最大、最高和最冷的冰帽,研究其内部运动速度、温度空间分布对气候变化的响应具有重要的意义.基于二维热耦合冰川动力学流线模型,以冰川表面观测温度、冰川运动速度及冰川几何形态作为输入,利用冰帽主流线物质平衡作为驱动,对古里雅冰帽在稳定态下的运动速度与温度分布进行模拟研究.通过对参数的敏感性分析表明,稳定态下在6200 m处的表面运动速度模拟值与实测值吻合较好.古里雅冰川的运动速度空间差异显著,消融区和末端的运动速率较低,而在积累区的运动速度较大;从中流线的纵剖面来看,冰川表面运动速度高于底部,且在冰川积累区尤其明显.该冰帽温度分布模拟结果和实测数据基本一致,且古里雅冰川的温度沿着中流线的纵剖面具有分异特点,冰川由表面到底部冰温逐渐升高,特别是在海拔6200 m处,底部冰温为-1.65℃,而冰川表面的温度为-16.2℃.最后,对模型存在的不确定性进行了分析,并由数值模拟结果得出冰川末端相对较小的应变率变化是古里雅冰帽长期处于基本稳定状态的原因之一.Glacier is an important component of the hydrological cycle at different temporal scales. A major mechanism of glacier formation is ＂metamorphosis＂, by which snow changes into ice. The process is affected by glacier temperature, velocity and mass balance. In recent decades, glaciers in the Western Kunlun Mountains manifested differently from those in other regions. Understanding the mechanism behind their abnormal response to climate change is pressing in order to predict their future trend. However, few simulation researches of Tibetan Plateau glacier change responding to climate warming have been done due to limitation of the availability of glaciological data in situ measurements. Knowledge of present-day ice temperature and velocity is important in order to determine how fast a glacier may respond to climate change. Guliya Ice Cap is located in the Western Kunlun Mountains which lies in the northwestern part of Tibetan Plateau. It is an extremely continental-type （cold） glacier and is characterized by low temperature and precipitation. Using the few observed data for ice temperature and surface velocity, we apply a two-dimensional higher-order thermomechanical towline dynamical model to simulate the ice temperature and velocity in steady-state along the main towline of Guliya Ice Cap. The rare but valuable observational data are used to validate the results of numerical simulation of the model in this study. Owing to the uncertainty of parameters＇ values, some diagnostic experiments have been conducted to simulate the present-day spatial distributions of ice velocity and temperature along the main towline of the Guliya Ice Cap. Based on the sensitivity experiments described above, the appropriate parameters on which the model can best simulate the present-day ice velocity and temperature distributions of Guliya are selected. Generally, modeled and observed ice surface velocities exhibit good agreement under the parameters we adopted. Our results show that significant spatial difference of velocity f

关 键 词：冰川动力学 古里雅冰帽 冰川运动速度 冰川温度 

分 类 号：P343.6[天文地球—水文科学]