为探讨近十几年来新疆天山地区植被净初级生产力时空格局及其对气候要素的响应机制,基于资源平衡的观点和光能利用率的概念,利用改进的光能利用率模型估算2001-2013年天山植被NPP,利用RS和GIS技术逐像元分析天山植被NPP时空分布特征及其与气候要素的相关关系,进而了解天山地区植被NPP对气候变化的响应机制,为天山地区生态环境保护和管理提供科学依据.具体方法包括:(1)将2001-2003年新疆地区MODIS-NDVI月产品数据、天山26个气象台站插值数据和2005年土地利用-覆盖数据进行预处理后作为参数输入到CASA模型中,估算出13 a天山地区植被NPP;(2)通过与其他研究NPP模拟结果进行对比,验证该文所采用的模型的模拟精度.研究结果表明,天山地区植被NPP总体呈西高东低,由北向南递减的空间分布特征;13a平均植被NPP(以C计,下同)和NPP总量分别为156.63 g·m-2·a-1、93.2 Tg·a-1(1Tg=1012 g);2001-2013年天山植被NPP总体呈缓慢增长趋势,NPP快速增长区零星分布在天山北坡的林地和耕地区,增长速率为25～55 g·m-2·a-1,草地NPP总量波动较为明显,林地和耕地NPP总量呈缓慢上升趋势,而荒漠NPP总量波动趋于平缓;植被NPP与年降雨量、年均温的平均相关系数分别为0.383和-0.189,天山地区植被NPP与年降雨量的相关性更强,降雨量是影响天山植被NPP的重要因子;不同类型植被NPP对气候要素的响应情况存在明显差异:天山林地、草地和荒漠植被NPP主要受降雨量影响,而耕地植被NPP同时受到降雨量和气温的限制.%In this paper,the Carnegie-Arnes-Stanford Approach (CASA) model,which was based on the theory of Resource Balance and Light Use Efficiency,was proposed to simulate Net Primary Production (NPP) of different vegetation types in the Tianshan Mountains Region (TMR) over the past few decades and its response to climatic factors.The inputs of the model include a set of monthly MODIS NDVI product data & meteorological interpolation data from 2001 to 2013 in this region.China Land use/cover data in 2005 was used to confirm the light utilization efficiency of different vegetation types.The process of the model was fulfilled by compiling programs with IDL in ENVI 5.1.The outputs of the model embrace annual NPP & NPP summation.In order to verify the simulation precision of the model,comparing with other NPP simulation results which research in similar regions by using different models.The results shows that,the spatial distribution of vegetation NPP in the TMR,by and large,decreased from west to east and increased from north to south.Average annual NPP (by C,the same below) and total NPP from 2001 to 2013 in TMR was 156.63 g·m-2·a-1 and 93.2 Tg·a-1 respectively.The vegetation NPP in the TMR showed a slowly increasing trend from 2001 to 2013.Among them,NPP rapid growth area scattered across the north slope of the forest and cropland in the TMR,with the growth rate of 25～55 g.m-2·a-1.The total NPP of grassland fluctuated obviously,forest and cropland had a increasing tendency slowly,while the total NPP of desert tended to be gentle.The average correlation coefficients of vegetation NPP with annual rainfall and annual mean temperature were 0.383 and-0.189.The response of NPP to annual rainfall is more sensitive than to the annual mean temperature in the study area.Rainfall is the major factor which affected the growth of vegetation in the TMR.There were significant differences in response of different types of vegetation NPP to climatic factors.The vegetation NPP of forest,grassland and desert in the TMR was mainly affected by rainfall,while NPP of cropland was limited both by rainfall and temperature.
展开▼
