基于MODIS-NDVI数据的植被碳汇空间格局研究——以石羊河流域为例

Spatial Pattern of Vegetation Carbon Sinks Based on MODIS-NDVI Data: A Case Study in Shiyang River Basin,China

本文以石羊河流域地表植被为研究对象,利用遥感影像数据、气象资料数据、DEM数据和土地利用数据,通过修正的CASA模型和土壤微生物呼吸模型计算石羊河流域生态系统NEP。在此基础上定量地划分出碳源、高碳汇区和低碳汇区,并对流域内碳源/汇空间分布进行详细研究。结果表明:石羊河流域净生态系统生产力(NEP)空间分布表现出由西南向东北逐渐递减的趋势,整体呈现出南高北低、高低相间的分布特征。研究区碳源/汇空间分布大体呈现条带状分布格局,碳源主要分布于下游民勤绿洲周边的沙漠区,低碳汇区主要分布于中游河西走廊平原,高碳汇区主要分布于上游祁连山区。由于光照等因子的差异,高碳汇区主要分布于阴坡其次是半阳坡和半阴坡,阳坡分布最少,低碳汇区主要分布于阴坡和半阳坡地区。研究结果能够较好地反映出石羊河流域植被生长及分布状况。

To analyze the net ecosystem productivity(NEP)in a small-scale local ecosystem,in this paper the Shiyang River basin was taken as a case study,which is a typical inland river basin in the arid of northwest China.NEP was calculated by the net primary productivity(NPP)and heterotrophic respiration(R H)based on MODIS images and meteorological data.By the calculated results of NEP,Shiyang River basin was divided into three parts,i.e.,the carbon source area,the high carbon sink and the low carbon sink area.The results showed that the proposed method was able to quickly extract ecosystem net primary productivity and carbon sinks for the Shiyang River basin more efficiently,conveniently and practically.The spatial distribution of NEP displayed a decreasing trend from southwest to northeast.Carbon sinks and carbon sources showed a stripe-shaped distribution pattern.Carbon sources were mainly distributed in the desert areas around the downstream Minqin oasis.Low carbon sinks were mainly distributed in the plains of Hexi corridor in the middle reaches,while the high carbon sinks were mainly distributed in the upper reaches of Qilian Mountain.Due to the differences in light and other factors,the high carbon sinks were mainly distributed on the shady slopes,followed by the semi-sunny slopes and the semi-shady slopes,and the sun slopes were the least.The low carbon sinks were mainly located on the shady slopes and semi-sunny slopes.The analysis also effectively revealed the growth and distribution of vegetation in the Shiyang River basin.