Evaluation of Sentinel-2 red-edge bands for empirical estimation of green LAI and chlorophyll content.
Evaluation of Sentinel-2 red-edge bands for empirical estimation of green LAI and chlorophyll content.
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DOI：
10.3390/s110707063
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Moreno J
中科院分区：
文献类型：
--
作者：
Delegido J;Verrelst J;Alonso L;Moreno J
ESA即将发射的Sentinel-2卫星将提供高空间、光谱和时间分辨率的地球图像，旨在确保Landsat和SPOT观测的连续性。与后者相比，Sentinel-2在红边区域增加了三个新的光谱带，其中心为705,740和783 nm。本研究探讨了这些新波段对两个重要生物物理参数：绿叶面积指数（LAI）和叶绿素含量（Ch）的检索和监测的重要性。利用欧空局在农业站点（SPARC, AgriSAR, CEFLES2）上进行的几次野外活动的数据，我们评估了两种专门利用新的Sentinel-2波段的经验方法的有效性。首先，利用高光谱数据，可以从通用归一化差指数（NDI）中得到LAI，其中674 nm和712 nm是表现最好的波段；这些波段靠近Sentinel-2 B4 （665 nm）和新的红边B5 （705 nm）波段。该方法已应用于Sentinel-2模拟数据。得到的绿色LAI图与不同作物类型的田间数据进行了验证，从而跨越了0到6之间的LAI，得到了0.6的RMSE。其次，研究了基于高光谱数据导出的“归一化面积过反射曲线”（NAOC）与Sentinel-2模拟数据的兼容性。该指数综合了643 ~ 795 nm之间的反射率曲线，因此在红边区域包含了新的Sentinel-2波段。我们发现这些新波段显著提高了Ch估计的精度。两种方法都强调了红边带对Sentinel-2生物物理参数操作估计的重要性。
ESA’s upcoming satellite Sentinel-2 will provide Earth images of high spatial, spectral and temporal resolution and aims to ensure continuity for Landsat and SPOT observations. In comparison to the latter sensors, Sentinel-2 incorporates three new spectral bands in the red-edge region, which are centered at 705, 740 and 783 nm. This study addresses the importance of these new bands for the retrieval and monitoring of two important biophysical parameters: green leaf area index (LAI) and chlorophyll content (Ch). With data from several ESA field campaigns over agricultural sites (SPARC, AgriSAR, CEFLES2) we have evaluated the efficacy of two empirical methods that specifically make use of the new Sentinel-2 bands. First, it was shown that LAI can be derived from a generic normalized difference index (NDI) using hyperspectral data, with 674 nm with 712 nm as best performing bands. These bands are positioned closely to the Sentinel-2 B4 (665 nm) and the new red-edge B5 (705 nm) band. The method has been applied to simulated Sentinel-2 data. The resulting green LAI map was validated against field data of various crop types, thereby spanning a LAI between 0 and 6, and yielded a RMSE of 0.6. Second, the recently developed “Normalized Area Over reflectance Curve” (NAOC), an index that derives Ch from hyperspectral data, was studied on its compatibility with simulated Sentinel-2 data. This index integrates the reflectance curve between 643 and 795 nm, thereby including the new Sentinel-2 bands in the red-edge region. We found that these new bands significantly improve the accuracy of Ch estimation. Both methods emphasize the importance of red-edge bands for operational estimation of biophysical parameters from Sentinel-2.
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影响因子：
13.5
作者：
Combal, B;Baret, F;Wang, L
通讯作者：
Wang, L
影响因子：
6.2
作者：
Casa, R.;Baret, F.;Jones, H. G.
通讯作者：
Jones, H. G.
影响因子：
3.4
作者：
Delegido, J.;Fernandez, G.;Moreno, J.
通讯作者：
Moreno, J.
影响因子：
13.5
作者：
Chen, JM;Pavlic, G;Pellikka, PKE
通讯作者：
Pellikka, PKE
影响因子：
3.4
作者：
Clevers, JGPW;De Jong, SM;Scholte, KH
通讯作者：
Scholte, KH