石羊河上游净生态系统生产力研究

On the Net Ecosystem Productivity in the Upper Reaches Area of Shiyang River

利用MODIS数据,结合CASA(carnegie ames stanford approach)模型和土壤呼吸拟合方程,对石羊河上游2003—2012年净生态系统生产力的空间格局及变化趋势进行了分析,并探讨了气候因子对区域碳源/汇的影响。结果表明:1 2003—2012年,石羊河上游地区年均NEP为126.96 g·m-2·a-1,NEP总量为1.38×1010t·a-1;近10 a NEP有明显的增加趋势。2 NEP空间分布呈现出由中部向南、北依次降低的空间格局;总体上表现为碳汇,只有小部分荒漠为碳源;不同生态系统NEP存在较大差异。这主要与研究区水热条件组合和植被类型有关。3 NEP的年际变化与气温和降水量呈正相关,降水量对NEP的影响大于气温,并且在空间上具有互补性。

By using MODIS data,combining with CASA（ Carnegie Ames Stanford that CASA） model and soil respiration fitting equation,this paper simulated the Net Ecosystem Productivity（ NEP） of different vegetation types in the upper reaches area of Shiyang River in 2012. The result shows that： 1 The NEP is 126. 96 g·m-2·a-1and the total annual NEP is 1. 38 × 1010t·a-1from 2003 to 2012,and it has been a marked increase in recent 10 years. 2 The NEP shows a spatial pattern,becoming lower in turns from the central to the north and south. Overall,it acts as a carbon sink,only a small part of the desert acts as a carbon source. There are larger differences between different ecosystems to the NEP. This is correlated to hydrothermal conditions and the different distribution of vegetation types in the study area. 3 Interannual variation of the NEP was positively related to the temperature and precipitation,the precipitation has a larger influence on NEP,and complementary in the space.