度日模型在冰川与积雪研究中的应用进展

Progress of the Application of Degree-Day Model to Study Glaciers and Snow Cover

度日模型是基于冰川与积雪消融和气温,尤其是冰雪表面的正积温之间的线性关系建立的.度日模型已广泛应用于北欧、阿尔卑斯山、格陵兰冰盖、青藏高原等地区的冰雪消融、冰川物质平衡及对气候敏感性响应、冰川动力模型以及冰雪融水径流模拟等的研究中.度日模型尽管是对冰雪表面消融能量平衡这一复杂过程的简化描述,但在流域尺度上,通常可以获取类似于能量平衡模型的输出结果.度日模型也有其不足之处,仍需进一步的改进与完善.

Degree-day model is one of the simple but sufficiently accurate ones to estimate ice or snow ablation. It bases on linear correlation between ablation and sum of daily mean temperatures above melting point, the cumulative positive temperature, during a period. Although more physically based energy balance models can describe more properly the processes of ice or snow ablation, the degree-day model has been used for more than a century for its convenience in practice. Comparing with another climate variables, air temperature is the most readily available data in general, hence, degree-day model becomes the most widely used method for calculating ice and snow ablation in the studies of mass balance, hydrological process, ice dynamic process and climate sensitivity. Despite its simplicity, it is demonstrated that the degree-day model is a powerful tool for ablation modeling on a catchment scale, rather than the energy balance models. Due to generally good performance, low data requirements and simplicity, the degree-day model is accepted widely at present and will be accepted in the future in snow and glacier ablation modeling. However, it is necessary to understand its limitations, in order to refine and develop.