冻土过程参数化方案与中尺度大气模式的耦合

将发展的冻土过程参数化方案与耦合了NCAR LSM陆面过程模式的中尺度大气模式MM5相耦合，对包括我国北方，蒙古国，东西伯利亚的高纬度地区进行了模拟．模拟时间选为北半球季节冻土生成的10月份。模拟结果表明，模式能够较好地模拟出该区域的冻土分布，并且对大气模式中海平面气压场、气温场的模拟改进显。

Frozen Soil Parameterization Scheme Coupled with Mesoscale Model

A simple frozen soil parameterization scheme is developed. It can be coupled with mososcale model system that coupled NCAR Land Surface Model (LSM), which considered the primary features of frozen soil as follows: 1) phase change in soil column is the source/sink term in energy budget, and soil ice content is set as a prognostic variables and can be solved by combination of freezing point depression equation and soil matrix potential relation; 2) a new parameterization of thermal conductance (J75) is adopted to replace the former one (Farouki, 1981), which can be more accurately described under frozen soil condition; 3) effect of soil ice on liquid water movement is considered and it also affects the partition of surface between infiltration and runoff. The simulation has been conducted over high latitude regions, including North China, Mongolia and East Siberia in October, when seasonal frozen soil is forming in the north hemisphere. The results indicate that the model can reasonably simulate frozen soil distribution. It is found that the simulated ice content and ground heat flux are related to the soil type and frozen depth. The simulation of sea level pressure field and air temperature field, therefore, can be evidently improved.