海洋学研究 ›› 2022, Vol. 40 ›› Issue (1): 64-71.DOI: 10.3969/j.issn.1001-909X.2022.01.007
悬浮泥沙质量浓度(SSC)是我国河口水体研究的重要水质参数之一,遥感测定SSC是一种重要的方法。为了研究遥感光谱数据和表层悬浮泥沙质量浓度(SSSC)之间的定量梯度关系,本文采集了长江口南汇嘴附近的表层沉积物,定量设计了SSSC的梯度变化值,利用ASD高光谱仪对不同质量浓度含沙水体进行了光学特性测量。结果表明,随着SSSC的增加,水体的光谱反射率曲线具有相似的形态,但也存在一定的差异。当SSSC<36.59 mg/L时,光谱曲线仅在560~580 nm之间有1个反射峰;当SSSC>52.69 mg/L时,光谱曲线第一反射峰位于570~710 nm,并在近红外波段780~820 nm处出现第二反射峰。光谱曲线第一峰值区间存在明显的“红移”现象,且波长的“红移”变化与SSSC的线性拟合R2达到0.91,说明两者呈较强的线性相关性。在400~900 nm光谱范围内,600~860 nm波段对0~200 mg/L范围内的SSSC变化较敏感且比较稳定,740~900 nm波段对>200 mg/L的SSSC的变化具有更强的响应能力。
Suspended sediment concentration (SSC) is one of the important water quality parameters in estuarine water research. Remote sensing determination of SSC is an important method. In order to study the quantitative gradient relationship between remote sensing spectral data and surface suspended sediment concentration(SSSC), the surface sediments near the Nanhuizui of the Changjiang (Yangtze River) Estuary were collected, the gradient changes of SSSC were designed quantitatively, and the optical characteristics of sediment laden water with different concentrations were measured by ASD hyperspectral spectrometer. The results show that with the increase of SSSC, the spectral reflectance curve of water has similar morphology, but there are also some differences. When SSSC<36.59 mg/L, the spectral curve has only one reflection peak at 560-580 nm. When SSSC>52.69 mg/L, the first reflection peak of the spectral curve is at 570-710 nm, and the second reflection peak appears at 780-820 nm in the near infrared band. There is an obvious “red shift” phenomenon in the first peak interval of the spectral curve, and the linear fitting R2 between the “red shift” change of wavelength and SSSC reaches 0.91, indicating a strong linear correlation between them. In the spectral range of 400~900 nm, 600-860 nm band is sensitive and stable to the change of SSSC in the range of 0~200 mg/L, and 740900 nm band has stronger response to the change of SSSC>200 mg/L.
摘要: 悬浮泥沙质量浓度(SSC)是我国河口水体研究的重要水质参数之一,遥感测定SSC是一种重要的方法。为了研究遥感光谱数据和表层悬浮泥沙质量浓度(SSSC)之间的定量梯度关系,本文采集了长江口南汇嘴附近的表层沉积物,定量设计了SSSC的梯度变化值,利用ASD高光谱仪对不同质量浓度含沙水体进行了光学特性测量。结果表明,随着SSSC的增加,水体的光谱反射率曲线具有相似的形态,但也存在一定的差异。当SSSC<36.59 mg/L时,光谱曲线仅在560~580 nm之间有1个反射峰;当SSSC>52.69 mg/L时,光谱曲线第一反射峰位于570~710 nm,并在近红外波段780~820 nm处出现第二反射峰。光谱曲线第一峰值区间存在明显的“红移”现象,且波长的“红移”变化与SSSC的线性拟合R2达到0.91,说明两者呈较强的线性相关性。在400~900 nm光谱范围内,600~860 nm波段对0~200 mg/L范围内的SSSC变化较敏感且比较稳定,740~900 nm波段对>200 mg/L的SSSC的变化具有更强的响应能力。
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