用于GCM耦合的积雪模型的设计

文中描述一个一维的积雪分层模型，目的是要刻划雪盖随季节的变化，与其下冻土变动模型一起，构成完整的雪盖模型。为了保持一定精度，并能用于大气环模式（ＧＣＭ）研究，模型对积雪内部热量及质量输送过程的描述精细程度及计算时分层多少均有所考虑。模型中，改用内能代替温度作为预报量，克服了相变时直接预报温度时造成的计算误差，有效地预报了相变过程。对于积雪密度的变化，考虑了雪花形态的破坏而引起的密度变化及由于压实过程而引起的密度变化。并对各分层自重产生压实过程推导了相应的公式，在模型中对雪盖的光学特性、热力学特性及水流流动特性参数化方案设计也进行了分析。本简化模型的模拟结果与精细积雪模型的比较，具有几乎同等的精度，与俄罗斯的Ｙｅｒ－ｓｈｏｖ站实测数据相比，吻合十分理想。

A SNOW MODEL DESIGN FOR COUPLING WITH GCM

It is a simplified and layered model to describe seasonal change of a snow cover.The model will be used to couple with frozen soil model being developed later.In order to keep the model more accuracy as well to be able in using in GCM study,the model takes into consideration the energy and mass transport processes as well scheme of layering snow pack carefully. In the model,the internal energy,instead of temperature,is used as predicted variable.It will help us to deal with phase change process and to reduce computational error more efficiently. As for snow density change,two processes leading snow more dense will be considered.They are metamorphism and compaction processes.The compaction effect from self weight of each sublayer is also considered because the sublayer may be very thick in the model.There are many parameters involved in the model,and it is explained to how to select the scheme to estimate these parameters. Comparison of simulation results from the model with more fine model shows that the model can almost predict results with same accuracy as the fine model did.The model also simulates the field observation data very well.