Trophic state assessment of global inland waters using a MODIS-derived Forel-Ule index
Trophic state assessment of global inland waters using a MODIS-derived Forel-Ule index
复制标题
使用 MODIS 衍生的 Forel-Ule 指数对全球内陆水域的营养状况进行评估
DOI：
10.1016/j.rse.2018.08.026
复制
发表时间：
2018-11-01
影响因子：
13.5
通讯作者：
Peng, Dailiang
中科院分区：
文献类型：
--
作者：
Wang, Shenglei;Li, Junsheng;Peng, Dailiang
内陆沃茨的富营养化被认为是一个严重的全球性环境问题。卫星遥感已被确立为一个重要的信息来源，通过检索叶绿素a等光学活性水质参数来确定内陆沃茨的营养状况。然而，使用遥感技术的内陆沃茨在全球范围内的营养状态的评估是阻碍了检索算法的性能超过高度动态和复杂的光学特性，这些系统的特点。在这项研究中，我们开发了一种新的RS方法来评估全球内陆水体的营养状态的基础上，中分辨率成像光谱仪（MODIS）图像和Forel-Ule指数（FUI）。首先，FIJI计算从MODIS数据划分天然水色为21个指数，从深蓝色到黄褐色。然后，在实地测量和MODIS产品的基础上，建立了FIJI和营养状态指数（TSI）之间的关系。在基于斐济的营养状态评价中，采用645 nm波段的离水反射率来区分有色溶解有机物（CDOM）占主导地位的系统。在此基础上，利用2012年夏季的MODIS数据，开发了基于FUI的营养状态评价方法，并应用于全球2058个大型内陆水体（表面积> 25 km 2）的营养状态评价。我们的研究结果表明，FUI可以从MODIS检索相当的准确性（92.5%，R-2 = 0.92），通过比较，在广泛的湖泊的同时在原位测量，和基于斐济的营养状态评估方法的整体准确性为80.0%（R-2 = 0.75）验证了一个独立的数据集。在所考虑的全球大型水体中，贫营养大型湖泊集中在中亚和南美洲南部的高原地区，而富营养大型湖泊则集中在中非、东亚以及北美中北部和东南部。
Eutrophication of inland waters is considered a serious global environmental problem. Satellite remote sensing (RS) has been established as an important source of information to determine the trophic state of inland waters through the retrieval of optically active water quality parameters such as chlorophyll-a (Chl-a). However, the use of RS techniques for assessment of the trophic state of inland waters on a global scale is hindered by the performance of retrieval algorithms over highly dynamic and complex optical properties that characterize many of these systems. In this study, we developed a new RS approach to assess the trophic state of global inland water bodies based on Moderate Resolution Imaging Spectroradiometer (MODIS) imagery and the Forel-Ule index (FUI). First, the FIJI was calculated from MODIS data by dividing natural water colour into 21 indices from dark blue to yellowish-brown. Then the relationship between FIJI and the trophic state index (TSI) was established based on in-situ measurements and MODIS products. The water-leaving reflectance at 645 nm band was employed to distinguish coloured dissolved organic matter (CDOM)-dominated systems in the FIJI-based trophic state assessment. Based on the analysis, the FUI-based trophic state assessment method was developed and applied to assess the trophic states of 2058 large inland water bodies (surface area > 25 km(2)) distributed around the world using MODIS data from the austral and boreal summers of 2012. Our results showed that FUI can be retrieved from MODIS with a considerable accuracy (92.5%, R-2 = 0.92) by comparing with concurrent in situ measurements over a wide range of lakes, and the overall accuracy of the FIJI-based trophic state assessment method is 80.0% (R-2 = 0.75) validated by an independent dataset. Of the global large water bodies considered, oligotrophic large lakes were found to be concentrated in plateau regions in central Asia and southern South America, while eutrophic large lakes were concentrated in central Africa, eastern Asia, and mid-northern and southeast North America.