黑河流域植被净初级生产力的遥感估算

Estimation of Net Primary Productivity of Heihe River Basin Using Remote Sensing

利用光能利用率模型C-FIX,高时空分辨率的SPOT/VEGETATION遥感数据,全球格网化气象再分析资料以及黑河流域土地利用图,估算了1998—2002年黑河流域不同生态系统净初级生产力(NPP)的年总量和平均生产力,输出了黑河流域NPP年累积量空间分布格局图、NPP季节动态图,分析了近5a来黑河流域NPP时空变化特征,评价了不同土地利用类型下的生态系统生产力水平差异。其结果表明,黑河流域陆地生态系统NPP空间分布及其季相变化特征是流域自然环境、地貌、气候以及人类生产活动长期共同作用和影响的结果,其中水分条件是控制黑河流域陆地生态系统NPP空间格局的决定因子。1998—2002年黑河流域山区高覆盖度草地和下游荒漠区净初级生产力持续下降,反映出这些地区生态环境恶化严重。这些研究结果可以为黑河流域的水-生态-经济系统的合理设计与有效实施提供科学数据集。

In this paper, the Monteith type parametric model-C-FIX, the 1 km SPOT4/VEGETATION data and the global meteorological data provided by Meteo France were used to estimate the net primary productivity （NPP） of the different ecosystems in the Heihe River Basin from the year of 1998 to 2002. The annual total NPP of the whole basin was estimated about 18. 16 Tg C（1 Tg = 10^12）. The annual mean NPP only equal to 106 g·m^-2·a^-1 over the study area of 128000km^2. The spatial pattern of the annual-accumulated NPP, the monthly dynamics of NPP as well as the NPP changes from 1998 to 2002 in the basin were illustrated and descript in detail. In addition, different ecosystems and their corresponding NPP were compared and evaluated by using the land-use map of the basin. The results showed that the spatial and temporal patterns of NPP in the Heihe River Basin were attributable to the complex interaction between natural environment, various climates and human activities. Among them, the restricted water resource was the main element to control the basin＇s NPP. Moreover, a continuously decrease NPP during the last five years existed in the closed grassland of the mountainous and the desert of the down streams, indicating a pronounced ecological degradation in these areas. The series of the NPP outputs and the evaluation results will be useful in the design and management of water-ecology-economy systems of the Heihe River Basin.