南极洛多姆冰帽BJ钻孔粒雪层的热学性质及其温度分布

THERMAL PROPERTIES AND TEMPERATURE DISTRIBUTION OF SNOW / FIRN LAYER IN BOREHOLE BJ ON THE LAW DOME ICE CAP, ANTARCTICA

根据详细的密度资料,对洛多姆冰帽BJ钻孔粒雪层的热学性质进行了讨论。应用非均匀介质热传导方程描述活动层温度分布。通过两种简化的层状结构和竖向运动模型给出了解析解。计算和实测温度差异的分析表明边界条件的选取非常重要。

Based on detailed data on density and temperature in a shallow (about 20m deep) borehole at 1043m a.s.l.on the Law Dome Ice Cap, Antarctica, thermal properties and temperature distribution of snow/ firn in the active layer are discussed. Refering to the review of works on thermal properties of snow by Yen (1981), we suggest that the relationship between thermal conductivity (λ) and density (ρ) may be expressed by a formula, λ= 0.0784+2.697 ρ2. Then the heat transfer equation in an ununifrom medium, i.e.with variable thermal parameters, is applied and solved analytically by two approaches, laminar structure and vertical movement models.Comparison of calculated and measured temeratures indicates that the first model is bettr to describe the actual temperature distribution in snow / firn layer on a glacier, but the latter is more convenient to use because of its simplicity .The difference between calculated and measured temperatures is mainly due to the determination of boundary conditions.