Sentinel-2数据的冬小麦地上干生物量估算及评价

发布时间：2018-08-19 05:55

【摘要】：作物生物量快速精确的监测对于农业资源的合理利用与农田的精准管理具有重要意义。近年来,遥感技术因其独特的优势已被广泛用于作物生物量的估算中。本文主要针对不同宽波段植被指数在冬小麦生物量(文中的生物量均是指地上干生物量)估算方面的表现进行探索。首先利用欧洲空间局最新的Sentinel-2A卫星数据提取出17种常见的植被指数,之后分别构建其与相应时期内采集的冬小麦地上生物量间的最优估算模型,通过分析两者间的相关性与敏感性,获取适宜进行生物量估算的指数。最后,绘制了研究区的生物量空间分布图。结果表明,所选的植被指数均与生物量显著相关。其中,红边叶绿素指数(CI_(re))与生物量的估算精度最高(决定性系数R~2为0.83;均方根误差RMSE为180.29 g·m~( 2))。虽然相关性较高,但部分指数,如归一化差值植被指数(NDVI)等在生物量较高时会出现饱和现象,从而导致生物量的低估。而加入红边波段的指数不仅能够延缓指数的饱和趋势,而且能够提高反演精度。此外,通过敏感性分析发现,归一化差值指数和比值指数分别在作物生长的早期和中后期对生物量的变化保持较高的敏感性。由于红边比值指数(SR_(re))和MERIS叶绿素敏感指数(MTCI)在冬小麦全生长季内一直对生物量的变化保持高灵敏性,二者是生物量估算中最为稳定的指数。
[Abstract]:Rapid and accurate monitoring of crop biomass is of great significance for rational utilization of agricultural resources and precision management of farmland. In recent years, remote sensing technology has been widely used in crop biomass estimation because of its unique advantages. In this paper, the performance of different broad band vegetation indices in estimating winter wheat biomass (all biomass in this paper refers to aboveground dry biomass) is explored. First, 17 common vegetation indices were extracted from the latest Sentinel-2A satellite data of the European Space Agency, and then the optimal estimation models between them and the aboveground biomass of winter wheat collected in the corresponding period were constructed respectively. By analyzing the correlation and sensitivity between the two indexes, an index suitable for biomass estimation was obtained. Finally, the spatial distribution map of biomass in the study area was drawn. The results showed that the selected vegetation indices were significantly correlated with biomass. Among them, the red edge chlorophyll index (CI _ (re) and biomass have the highest estimation accuracy (decisive coefficient R _ (2) = 0.83; root mean square error (RMSE) = 180.29 g m ~ (2). Although the correlation is high, some indexes, such as normalized difference vegetation index (NDVI), will be saturated when the biomass is high, which leads to the underestimation of biomass. The index with red edge band can not only delay the saturation trend of the exponent, but also improve the inversion accuracy. In addition, it was found that the normalized difference index and the ratio index remained highly sensitive to biomass changes in the early and middle stage of crop growth, respectively. The red edge ratio index (SRS _ (re) and MERIS chlorophyll sensitive index (MTCI) have been highly sensitive to biomass changes during the whole growing season of winter wheat. They are the most stable indices in biomass estimation.
【作者单位】：中国科学院遥感与数字地球研究所数字地球重点实验室;中国科学院大学;
【基金】：2013年粮食公益性行业科研专项(编号:201313009-2) 国家重点研发计划项目(编号:2016YFA0600304,2016YFA0600302) 2014年粮食公益性行业科研专项(编号:201413003-7)~~
【分类号】：S512.11;S127

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