基于CASA模型的玉溪市NPP时空变化分析

Analysis on Temporal and Spatial Variation of NPP in Yuxi City Based on CASA Model

净初级生产力是陆地生态系统碳汇的决定因子,是生态系统中物质与能量流动研究的基础。为了解玉溪市净初级生产力时空变化情况及其与影响因子的相互关系,利用CASA模型对玉溪市2000年、2005年、2010年、2015年净初级生产力进行了估算,并从时间、空间变化及其与DEM、NDVI等的空间关系进行了分析。结果表明:(1)玉溪市15年间净初级生产力均值呈先"减小后增大再减小"的趋势。(2)各地区净初级生产力空间差异明显,西南部地区最高,东北部地区最低;15年间西部与西南部地区减少较明显,北部与东北部地区增加较明显。(3)净初级生产力均值总体随海拔的上升而增大,与DEM、NDVI呈正相关。在海拔较高区域,与NDVI相关性较大;在海拔较低区域,与DEM相关性较大。

Net Primary Productivity（NPP） was a determining factor of terrestrial ecosystem carbon sink, and it was the basis of research on mate-rial and energy flow in ecosystem. For a detailed understanding of the temporal and spatial variation of the NPP in Yuxi City and its relationship withthe image factors, in this paper, CASA model was used to estimate the mean NPP of 2000,2005,2010 and 2015in Yuxi City. In addition, the authorsanalyzed the spatial and temporal variation of NPP and the relationships between the NPP and DEM, NDVI. The results showed that：（DOver the past15 years（2000 - 2015 ）, the mean NPP in Yuxi City changed in volatility：First decreased and then increased, then decreased. （1）The spatial differenceof the mean NPP in Yuxi City was obvious, with the highest in the southwest region and the lowest in the northeast region. At the same time, the de-crease of NPP was obvious in the west and southwest of Yuxi City in fifteen years, and the northern and northeastern regions increased significantly. （2）In generally, the mean NPP of Yuxi City increased with the increase of DEM, and it was positively correlated with elevation and normalized differencevegetation index. Meanwhile, the correlation between the NPP and the normalized difference vegetation index was big in high altitude areas, but thecorrelation between NPP and DEM was big in the low altitude areas.