Hyperspectral remote sensing offers an effective approach for frequent, synoptic water quality measurements over a large spatial extent. However, the optical complexity of case 2 water makes the water quality monitori...Hyperspectral remote sensing offers an effective approach for frequent, synoptic water quality measurements over a large spatial extent. However, the optical complexity of case 2 water makes the water quality monitoring by remote sensing in estuarine water a challenge. The prime objective of this study was to develop algorithms for hyperspectral remote sensing of water quality based on in situ spectral measurement of water reflectance. In this study, water reflectance spectra R(λ) were acquired by a pair of Ocean Optic 2000 spectroradiometers during the summers from 2008 to 2011 at Patuxent River, a tributary of Chesapeake Bay, USA. Simultaneously, concentrations of chlorophyll a and total suspended solids (TSS), as well as absorption of colored dissolved organic matter (CDOM) were measured. Empirical models that based on spectral features of water reflectance generally showed good correlations with water quality parameters. The retrieval model that using spectral bands at red/NIR showed a high correlation with chlorophyll a concentration (R2 = 0.81). The ratio of green to blue spectral bands is the best predictor for TSS (R2 = 0.75), and CDOM absorption is best correlated with spectral features at blue and NIR regions (R2 = 0.85). These empirical models were further applied to the ASIA Eagle hyperspectral aerial imagery to demonstrate the feasibility of hyperspectral remote sensing of water quality in the optical complex estuarine waters.展开更多
对两种颗粒吸收光谱测量方法的差异性及在二类水体中的适用性进行了研究.通过理论推导指出.颗粒后向散射是T方法(Transmittance method)较T—R方法(Transmittance and Reflectance method)测量结果偏高的首要原因,并且其偏高程...对两种颗粒吸收光谱测量方法的差异性及在二类水体中的适用性进行了研究.通过理论推导指出.颗粒后向散射是T方法(Transmittance method)较T—R方法(Transmittance and Reflectance method)测量结果偏高的首要原因,并且其偏高程度同时取决于颗粒的后向散射和吸收性质;对福建沿岸典型二类水体同时采用两种方法测量的结果表明:与T—R方法相比.T方法测量所得总颗粒、非藻类颗粒、藻类颗粒的光学密度.在400~700nm波段的平均相对误差分别为38.5%、40.0%、33.1%.根据理论推导和实际测量分析结果,提出在中国近海二类水体中需采用T—R方法来替代T方法测量颗粒吸收光谱的建议.展开更多
文摘Hyperspectral remote sensing offers an effective approach for frequent, synoptic water quality measurements over a large spatial extent. However, the optical complexity of case 2 water makes the water quality monitoring by remote sensing in estuarine water a challenge. The prime objective of this study was to develop algorithms for hyperspectral remote sensing of water quality based on in situ spectral measurement of water reflectance. In this study, water reflectance spectra R(λ) were acquired by a pair of Ocean Optic 2000 spectroradiometers during the summers from 2008 to 2011 at Patuxent River, a tributary of Chesapeake Bay, USA. Simultaneously, concentrations of chlorophyll a and total suspended solids (TSS), as well as absorption of colored dissolved organic matter (CDOM) were measured. Empirical models that based on spectral features of water reflectance generally showed good correlations with water quality parameters. The retrieval model that using spectral bands at red/NIR showed a high correlation with chlorophyll a concentration (R2 = 0.81). The ratio of green to blue spectral bands is the best predictor for TSS (R2 = 0.75), and CDOM absorption is best correlated with spectral features at blue and NIR regions (R2 = 0.85). These empirical models were further applied to the ASIA Eagle hyperspectral aerial imagery to demonstrate the feasibility of hyperspectral remote sensing of water quality in the optical complex estuarine waters.
文摘对两种颗粒吸收光谱测量方法的差异性及在二类水体中的适用性进行了研究.通过理论推导指出.颗粒后向散射是T方法(Transmittance method)较T—R方法(Transmittance and Reflectance method)测量结果偏高的首要原因,并且其偏高程度同时取决于颗粒的后向散射和吸收性质;对福建沿岸典型二类水体同时采用两种方法测量的结果表明:与T—R方法相比.T方法测量所得总颗粒、非藻类颗粒、藻类颗粒的光学密度.在400~700nm波段的平均相对误差分别为38.5%、40.0%、33.1%.根据理论推导和实际测量分析结果,提出在中国近海二类水体中需采用T—R方法来替代T方法测量颗粒吸收光谱的建议.