熊俊麟, 范宣梅, 窦向阳, 杨莹辉. 藏东南然乌湖流域雅弄冰川流速季节性变化[J]. 武汉大学学报 ( 信息科学版), 2021, 46(10): 1579-1588. DOI: 10.13203/j.whugis20210104
引用本文: 熊俊麟, 范宣梅, 窦向阳, 杨莹辉. 藏东南然乌湖流域雅弄冰川流速季节性变化[J]. 武汉大学学报 ( 信息科学版), 2021, 46(10): 1579-1588. DOI: 10.13203/j.whugis20210104

藏东南然乌湖流域雅弄冰川流速季节性变化

  • 摘要: 冰川流速是表征冰川运动的重要参数之一,对于冰川动力学、气候变化以及物质平衡等研究具有重要意义。冰川流速的影响因素多样,其中气象因子主要是通过改变冰川物质平衡、活动性以及水力特征来对冰川运动产生影响,所以冰川流速也可能与气象因子一样具有季节性差异。基于2017-11-06—2020-11-02期间31景哨兵1号(Sentinel-1)雷达影像,采用外部数字高程模型(digital elevation model,DEM)辅助的偏移量追踪法对中国西藏自治区昌都市八宿县境内然乌湖流域的雅弄冰川进行了冰川表面流速提取,并结合研究区冰舌面积变化以及气象因子(平均气温、降水量、降雪日数以及平均日照数)对雅弄冰川流速季节性变化进行了分析。结果表明:雅弄冰川流速分布呈现中上部流速高而下部流速低的特点,且冰川中部主流线流速明显高于两侧速度。30组冰川流速变化具有明显的季节性,夏季流速高而冬春季流速低。与流速变化相同,冰舌面积变化同样具有季节性差异,冬季面积明显大于夏季面积。与气象影响因子对比分析发现,气温、降水以及日照均对冰川表面流速具有正效应,促进冰川运动,而降雪抑制了部分热量及辐射传递,进而抑制了冰川融水过程,减缓了冰川运动。在气象因子影响力上,气温对冰川运动的效应最明显,降雨次之,日照影响最小。

     

    Abstract:
      Objectives  As a primary parameter of glacier movement, glacier velocity is widely applied in research fields such as glacier mass balance and dynamics, climate change, and hydro-climate models throughout the cryosphere. Meteorological factors play an essential role in the glacier movement by changing the glacier mass balance and hydraulic characteristics. Therefore, the glacier velocity may have the same seasonal characteristic as meteorological factors.
      Methods  DEM(digital elevation model)-assisted offset tracking method was applied to extract the surface velocity of Yalong glacier with 31 Sentinel-1 radar images from November 2017 to November 2020. Combined with the area change of the glacial tongue and meteorological factors (e.g., average temperature, precipitation, snowfall days and average sunshine hours), the seasonal velocity change of Yalong glacier was analyzed.
      Results  The velocity distribution of Yalong glacier shows that there is high velocity in the upper part and low velocity in the lower part, and the velocity in the mainstream is obviously higher than that on both sides. Thiry sets of data prove that the variation of glacier velocity has apparent seasonality, with high velocity characteristics in summer and low in winter and spring. The variation of the glacial tongue has seasonal characteristics consistent with the glacier velocity, the glacial tongue area in winter is significantly larger than in summer. One possible reason is that glaciers have a higher velocity in summer, and most of the ice enters nearby glacial lakes as the glaciers melt or move.
      Conclusions  The analysis of meteorological factors such as temperature, precipitation, and sunshine proves their promoting effect on glacier movement. Meanwhile, the temperature effect relatively lags in winter and spring and there is no timely feedback. In terms of the influence of meteorological factors, the temperature has the most apparent effect on glacier movement, followed by rainfall, and sunshine has a minor effect.

     

/

返回文章
返回