砾石参数化对青藏高原陆面过程模拟的影响及敏感性分析

Impact and Sensitivity Analysis of Gravel Parameterization on Simulation of Land Surface Processes on the Qinghai-Xizang Plateau

将砾石参数化方案加入陆面模式CLM4.5中,验证了新方案在模式中的适用性且土壤温湿度模拟效果优于原方案,有效提升了深层土壤温度峰值和土壤含水量谷值的模拟。利用新方案研究土壤中不同砾石含量对陆面过程的影响分析发现:土壤导热率随砾石含量增多而增大,使深层土壤夏季(冬季)吸热(放热)增强,模拟值升高(降低)。土壤含水量大(小)的时候土壤导水率随砾石含量增多而增大(减小),造成土壤含水量模拟值减小(增大)。同时砾石的增多减小了冬季深层土壤温度的模拟值,使深层更多的水变成了冰,进一步减小了土壤导水率,造成深层土壤含水量模拟值的减小。砾石改变了土壤水热过程,进而影响了地表辐射通量和能量通量的变化,各月份砾石含量的不同对其贡献均有所不同,总贡献表现为随砾石含量的增多,土壤净辐射减小。

The gravel parameterization scheme is added to the land surface model CLM4.5,which verifies the applicability of the new scheme in the model and the simulation effect of soil temperature and humidity is better than the original scheme.The simulation of the peak soil temperature and the valley value of soil water content is effectively improved.The new scheme was used to study the effect of different gravel content on the land surface process.The analysis found that the soil thermal conductivity increases with the increase of gravel content,which increases the endothermic(exothermic)heat of the deep soil in summer(winter)and increases(reduces)the simulated value.When the soil water content is large(small),the soil hydraulic conductivity increases(decreases)with the increase of the gravel content,which causes the simulated value of the soil water content to decrease(increased).At the same time,the increase of gravel reduces the simulation of deep soil temperature in winter,making more water in the deep layer become ice,further reducing the soil hydraulic conductivity,and causing the simulation of deep soil water content to decrease.Gravel changes the soil hydrothermal process,which affects the surface radiation flux and energy flux.The contribution of different gravel contents in each month was different,and the total contribution showed that the net soil radiation decreased with the increase of gravel content.