应用MODIS影像数据估测台湾陆域生态区之净初级生产力

Using MODIS image data to estimate the terrestrial net primary productivity(NPP) of ecological zone in Taiwan

净初级生产力为研究全球气候变迁与陆域生态系的核心资料之一。净初级生产力之估算有很多种方式,应用遥测数据估算净初级生产力为目前的发展趋势。MODIS初级生产力产品(MOD17)系以1km空间解析力及8d的时间解析力,进行实时监测性及重复性的监测植被净初级生产力数据,该项数据对监测生态环境、自然资源和环境之变化有很大的帮助。本研究以2001—2006年之6年间的净初级生产力与不同生态区之净初级生产力推估,比较MODIS所推估之净初级生产力与其他不同方式所推估之净初级生产力的差异性,以了解MODIS推估台湾不同陆域生态系之净初级生产力的适宜性。研究结果显示:2001—2006年之净初级生产力主要集中于1000～1500g/(cm2·a)区间,占总面积百分比于24.2%～54.5%之间,平均值为1035.64g/(cm2·a)。其气候生态区之净初级生产力与前人研究的其他方法所推测之数值比较,显示MODIS对于台湾全岛尺度之NPP估测具有其可靠性。

Net primary productivity （NPP） estimation was one of the most important issues in studies of global climate change and terrestrial ecosystems. Remote sensing data, among others, is currently the most popular method used to estimate NPP. MODIS primary productivity products （MOD17） were the first regular, near-real-time data sets for repeated monitoring of vegetation primary productivity on vegetated land at 1 km resolution in an 8-day interval. It was advantageous for monitoring ecological conditions, natural resources and environmental changes. In this research, we studied the suitability of MODIS NPP in Taiwan. We explored the differences in the time-variant NPP and compared the results with previous studies. Six years of MODIS image data （2001 to 2006） were used to construct the NPP map, and the results of time-variant NPP data analyzed statistically. The results showed that during the years 2001 - 2006, the NPP data concentrated mainly in the 1 000 - 1 500 g/（cm^2 ·year） with an average of 1 035.64 g/（cm^2year） , accounting for 24.2% -54.5% of that of the total area. A comparison of NPP data of ecological zone indicated that NPP data was within the range of results of previous studies, which proved that the application of MODIS NPP in Taiwan was reliable.