陆面模式Noah-MP模拟地表热通量的物理过程不确定性分析

Uncertainty analysis of physical process on surface heat flux simulation in Noah-MP land surface model

陆面过程中的热量交换对于确定生态系统中的水文循环、边界层发展、天气和气候至关重要,然而目前陆面模式Noah-MP对地表热通量模拟的偏差在-180~180 W·m^-2之间,为明确模拟不确定性来源,本研究基于FLUXNET全球热通量观测数据,在5种气候类型、9类下垫面系统定量评估了Noah-MP感热和潜热通量模拟的不确定性.结果表明:Noah-MP在不同类型下对感热和潜热通量模拟的平均误差主要分布在-80~10 W·m^-2和-30~10 W·m^-2之间,模型在气候类型为热带和干旱气候以及下垫面类型为草地、针叶林、落叶阔叶林的模拟误差最大.研究发现植被过程是热通量模拟不确定性的主要来源,其次是水文过程和土壤过程;其中动态植被模型(DVEG)是植被过程模拟的主导因子,其次是湍流输送过程(SFC)、冠层气孔阻抗(CRS)和冠层辐射传输(RAD).

Heat exchange in the land surface process is essential to determine hydrological cycles,boundary layer development,weather and climate in ecosystems.The bias of the surface heat flux simulated by Noah-MP land surface model ranged between-180 and 180 W·m^-2.To investigate the sources of uncertainty in simulation,this study systematically assesses the uncertainty of Noah-MP sensible and latent heat flux simulation in 5 climate zones and 9 land cover types based on FLUXNET global heat flux observation data.The result shows that the average error of sensible and latent heat flux simulation is-80~10 W·m^-2 and-30~10 W·m^-2at different types,respectively,with the largest simulation error found in the climate zone of tropical and arid,and land cover types of grassland,evergreen needle-leaved forest and deciduous broad-leaved forest.Vegetation land surface processes are the primary source of uncertainty in heat flux simulation,followed by water and soil land surface processes.The Dynamic Vegetation Model(DVEG)is the dominant factor affecting vegetation process simulation,followed by Surface Exchange Coefficient for Heat,CH(SFC),Canopy Stomatal Resistance(CRS)and Radiation Transfer(Rad).