阔叶红松林净初级生产力模型参数的敏感性

Sensitivity of parameters in net primary productivity model of broadleaf-Korean pine mixed forest

PnET-Ⅱ(photosynthesis and evapotranspiration)模型是生态系统过程模型,运行过程中所需的参数较多,包括植被、土壤和气候参数等.本文估计了丰林自然保护区阔叶红松林中红松和阔叶树的总净初级生产力(NPP)和枝干NPP对PnET-Ⅱ模型参数变化的敏感程度.结果表明:PnET-Ⅱ模型的植被参数中,林冠参数变化对模拟结果影响较大,且红松总NPP对植被参数的敏感性大于阔叶树;红松和阔叶树NPP对土壤持水量变化敏感性较小,且红松NPP对土壤持水量的敏感性略小于阔叶树;在气候情景范围内,气温变化对红松和阔叶树NPP的影响最大,降水和光合有效辐射次之.不同气候情景对NPP模拟结果的影响不同.红松和阔叶树的总NPP和枝干NPP对各输入参数的敏感程度并不完全一致.

PnET-Ⅱ（photosynthesis and evapotranspiration） model is an ecosystem process model, which requires extensive input parameters, including vegetation parameters, soil parameters and climate parameters, to simulate net primary productivity （NPP）. This study estimated the total and wood （stem and branch） NPPs of Korean pine and broadleaf species in Fenglin Natural Reserve, and examined the responses of the NPPs to the variations of the input parameters in PnET-Ⅱ model. The simulation results indicated that among the vegetation parameters in PnET-Ⅱ model, the variation of canopy parameters had greater effects on the simulated NPPs of Korean pine and broadleaf species, and the response of Korean pine＇ s total NPP to vegetation parameters was larger than that of broadleaf species＇. The variation of soil water holding capacity （WHC） had smaller effects on the NPPs of Korean pine and broadleaf species, and the response of Korean pine＇ s NPP to the WHC was somewhat smaller than that of broadleaf trees＇. In climate scenarios, the variation of air temperature had the greatest effects on the simulated NPP of Korean pine and broadleaf trees, followed by precipitation and radiation. Different climate scenarios had different effects on the predicted results. The total and wood NPPs of Korean pine and broadleaf trees had different responses to the input parameters.