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对于天然淡水冰而言,冰温是决定其性质的关键因素。基于对黑龙江红旗泡水库淡水冰现场实测冰温、辐射等数据的分析,利用冰温数据探讨天然淡水冰热扩散系数受冰温度的影响情况。借鉴文献中淡水冰热传导系数、比热和密度等的研究成果,通过建立最优控制模型的方法,从数学角度上说明了水库天然淡水冰温度对热扩散系数的影响:在相对高冰温区域热扩散系数变化显著,随冰温升高明显降低,并趋于水的热扩散系数值;在相对低冰温区域热扩散系数变化缓慢,随冰温降低逐渐趋于稳定。所证明的高温区域热扩散系数的剧烈变化趋势的存在性为天然淡水冰热扩散系数与淡水热扩散系数之间的过渡赋予了较为合理的物理解释。最后,对辨识的天然水库淡水冰热扩散系数的变化做了简单讨论。
For natural freshwater ice, ice temperature is the key factor that determines its nature. Based on the data of ice temperature and radiation measured at the freshwater ice field of Hongqifo reservoir in Heilongjiang province, the influence of ice temperature on the freshwater ice thermal diffusion coefficient was discussed based on the ice temperature data. Based on the research results of freshwater ice thermal conductivity, specific heat and density in the literatures, the influence of natural freshwater ice temperature on thermal diffusivity is illustrated mathematically from the point of view of mathematical model: The coefficient of thermal diffusivity changes significantly with the increase of ice temperature, and tends to the value of thermal diffusivity of water. The coefficient of thermal diffusivity changes slowly at relatively low ice temperature, and tends to be stable with the decrease of ice temperature. The existence of the sharp trend of the thermal diffusivity in the high temperature region proves to be a reasonable physical explanation for the transition between the natural freshwater ice thermal diffusivity and the freshwater thermal diffusivity. Finally, a brief discussion is made on the change of thermal diffusion coefficient of freshwater identified in natural reservoirs.