冰川表面水文过程研究进展

冰面水文过程是冰川径流过程的重要组成部分,对于冰川运动与物质平衡具有重要影响.冰川表面在太阳辐射、冰川物理性质、冰面地形和成冰带空间分布等多种因素影响下消融,形成以冰面水系为主线,锅穴、冰裂隙、冰面湖等为端点的冰面融水输送与分配体系.深入理解冰面水文过程,掌握冰川表面融水的输送、存储与释放,对于研究短时间尺度的冰川融水径流过程、探索冰川动态响应机理具有重要意义.总结回顾了目前国内外冰面水文过程的研究现状,提出了该领域有待解决的主要科学问题.

Supraglacial drainage system: a review

Supraglacial drainage system is one of the most important parts of glacial drainage systems,which impacts glacier surface ablation processes through transfer and drainage of surface meltwater.The existence of supraglacial drainage system also significantly impacts glacier flow and dynamics.Most of the conventional glacier hydrologic models suggest that surface meltwater can efficiently drain from glaciers and thus ignore the ability of supraglacial drainage system to retain meltwater.However,the impact of this retention,which leads to large uncertainties in glacier runoff prediction,could not be ignored.Therefore,it is crucial to improve the understanding in supraglacial drainage systems.The formation of supraglacial drainage system is controlled by glacier size,physical characteristics and ablation zone distribution.There is a seasonal development process of supraglacial drainage system from subsurface flow to slush flow and then to open channel flow.This dynamic supraglacial drainage system can route glacial surface meltwater into moulins,ice crevasses or supraglacial lakes through supraglacial networks with variable efficiencies and delays over space and time.In this paper,an attempt is tried to review the current supraglacial drainage system studies,and to discuss the evolution,distribution and constitution of supraglacial drainage system in sequence and their roles in meltwater transfer and drainage.In particular,hydrodynamics of supraglacial networks are discussed in detail to illustrate the pattern,efficiency and meltwater partition of supraglacial drainage system.