CASA模型的改进及在干旱区生态系统NPP估算中的应用

Improving the CASA model and applying it to estimate the net primary productivity of arid region ecology system

CASA模型是针对北美地区植被而建立的净第一性生产力(NPP)模型,当前,该模型已被广泛应用于陆地生态系统NPP的估算。由于模型是针对北美地区植被而建立,因此,模型在不同于北美地区应用时,其参数需要进行修正。现在已有一些关于CASA模型修正的研究,但修正均未体现干旱区特点。文中以甘肃省为例,在充分考虑干旱区特点基础上,从土地利用/覆盖类型的划分、最大光能利用率的取值、高精度气象数据的选择以及遥感影像数据的选择等方面,对利用CASA模型进行干旱区生态系统NPP估算过程进行改进,使该模型更适用于干旱区。利用改进后的CASA模型模拟了甘肃省各土地利用/覆盖类型的NPP,获得了较高的精度,研究利于探索干旱区生态系统碳计量方法。

CASA （Carnegie Ames Stanford Approach） model was bulk to evaluate the net primary productivity （NPP） of vegetations in North America. At present, the CASA model had been used for estimating the NPP of land ecology system widely. Because the CASA model was built based on the vegetations in North America, the parameters of CASA model needs to modify when it is used in other regions which is different from North Ameri- ca. At present, there were some researches on adjusting the parameters of CASA model, while these researches did not consider the characteristic of arid region. Take Gansu province as a case in this paper, from these aspects such as dividing the land use/land cover types, quantifying the maximum light use efficiency, adopting the high resolution weather data and remote sensing images to improve the estimation NPP process of arid region ecology system by applying the CASA model based on considering the characteristic of arid region fully, and to make the CASA model suitable to estimate the NPP of different land use/land cover types in arid region more accurately. A high simulated precision of NPP to different land use/land cover types in Gansu province had been gotten by adopting the improved CASA model. The study would be benefit to explore the carbon accounting methods of arid region ecology system.