CoLM陆面模式对中亚干旱荒漠草地生态系统陆面过程的数值模拟

Simulation analysis of land surface processes in central Asian desert grassland ecosystems using CoLM

鉴于陆面模式在干旱半干旱区模拟性能较差,本研究运用Common Land Model(CoLM)陆面模式对中亚干旱荒漠草地生态系统进行了站点验证,检验其在该区域的模拟性能,并分析了其陆面特征。结果表明,不同水分状况的草地生态系统在能量分配上表现出明显的差异性,干旱特征明显的阜康站和咸海站能量分配表现为以感热通量为主;水分状况较好的巴尔喀什湖站能量分配以潜热通量为主。CoLM陆面模式对典型干旱荒漠草地生态系统的陆面过程有较好的模拟性能,能正确描述能量通量的日变化特征。模型对研究站点夜晚感热通量、土壤热通量的模拟效果不太理想,夜间感热通量模拟值略高于观测值,土壤热通量模拟明显低于观测值,在3个研究站点土壤热通量偏差均大于50 W/m^2,不能很好地描述昼夜温差较大的干旱区夜间较强的土壤热通量交换过程。

The performance of a land surface heat flux model known as the Common Land Model（CoLM）was investigated in arid and semi-arid areas,in desert grassland ecosystems over Central Asia.The model performance was tested for three sites;Fukang,the Aral sea,and Balhash Lake,and the characteristics of the land surface were also analyzed for these three sites.It was found that water status of the grassland ecosystem had a major impact on the pattern of energy flux.Sensible heat flux was the dominant component of the diurnal energy balance at the Fukang site and Aral sea sites,which displayed obvious drought characteristics.The dominant energy component was the latent heat flux at Balhash Lake site,which was less arid than the other sites.CoLM performed well in typical desert grassland ecosystems,and correctly described the diurnal variation in energy fluxes.The simulations for sensible heat flux and ground heat flux overnight were less accurate.At night,the simulated sensible heat flux was higher than the observed values,and the simulated ground heat flux was significantly lower than the observed data.The deviation was greater than 50W/m2 at each site.The model does not adequately describe the soil heat flux exchange process at night in arid areas which have a large temperature differential between day and night.