基于高光谱反射率的江苏大丰麋鹿国家级自然保护区水体营养状态评价

以归一化和一阶微分光谱反射率为自变量,建立江苏大丰麋鹿国家级自然保护区核心区水体中的叶绿素a、总氮和总磷含量的估算方程;采用修正营养状态指数方法,评价该保护区核心区水体的营养状态。研究结果表明,叶绿素a、总氮和总磷含量的敏感波段分别为514 nm、680 nm和737 nm;以一阶微分光谱反射率为自变量建立的叶绿素a和总氮含量估算方程精度较高,以归一化光谱反射率为自变量建立的总磷含量估算方程的精度相对最高;江苏大丰麋鹿国家级自然保护区第一和第二核心区的水体处于中度富营养状态,第三核心区人工河流水体的营养状态由中度富营养向轻度富营养转变,第三核心区自然河流水体处于中、轻度富营养状态。

Assessment of Nutritional Status of Water Bodies in Jiangsu Dafeng Milu National Nature Reserve based on Hyperspectral Reflectance

The quality of water bodies of the natural and constructed rivers in the core areas of Jiangsu Dafeng Milu National Nature Reserve was assessed with the modified trophic state index approach, on the basis of constructing the relationship between field reflectance hyperspectral and concurrent chlorophyll-a, total nitrogen, total phosphorus concentrations. The hyperspectral reflectance were measured with ASD Field Spec spectrometer in October 2018. The results showed the normalized and first-derivative hyperspectral reflectances were highly correlated with water quality parameters. Furthermore, the first-derivative reflectances at 514 nm and 680 nm were most appropriate to estimate chlorophyll-a, total nitrogen concentrations respectively, and the normalized reflectance around 737 nm was optimal for estimating total phosphorus concentration. The evaluation finding indicated the water bodies in the first and second core areas of the reserve were both in moderate eutrophication level, the constructed river water in the third core area varies from mesotrophic to light eutrophication level, and the water bodies of natural river in the third core area were in moderate or light eutrophication state.