Estimation of suspended sediment concentrations using Terra MODIS: an example from the Lower Yangtze River, China.
Estimation of suspended sediment concentrations using Terra MODIS: an example from the Lower Yangtze River, China.
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DOI：
10.1016/j.scitotenv.2009.11.057
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发表时间：
2010-02
期刊：
影响因子：
--
通讯作者：
Jian-jun Wang;Xixi Lu
中科院分区：
文献类型：
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作者：
Jian-jun Wang;Xixi Lu
传统的河流悬浮泥沙浓度测量方法是通过现场采样进行的，既昂贵又耗时。因此，这些方法不能提供连续的SSC记录。虽然遥感已被用于SSC的估计，很少有研究已经进行了内陆河流，特别是像长江高浊度的河流。已有研究提出将Landsat TM/ETM+ Band 4作为长江泥沙含量的光谱指示器，但其时间分辨率的局限性不足以用于泥沙动态变化的研究。本文提出了一种利用高时间分辨率Terra MODIS时间序列数据估算长江九江段悬浮物浓度的方法。结果发现，在波段2和波段5之间的水反射率的差异可以提供相对准确的SSC估计，即使在原位大气条件是未知的。交叉验证后，平均绝对相对误差（ARE）和相对均方根误差（RRMSE）相对较低（即，25.5%和36.5%）。该经验关系式成功地应用于长江下游大通站的SSC估算，尽管SSC值普遍被低估。本研究表明，Terra MODIS可以用于估算大型浑浊河流中的SSC，但一些影响因素需要进一步研究，以提高SSC估算的准确性。
Traditional measurements of suspended sediment concentrations (SSC) through in-situ sampling in rivers are expensive and time-consuming to perform. Thus, these methods cannot provide continuous SSC records. Although remote sensing has been used for SSC estimation, little research has been undertaken on inland rivers, especially for highly turbid rivers like the Yangtze. Previous studies have proposed Landsat TM/ETM+ Band 4 as a spectral SSC indicator for the Yangtze, but its limitation on temporal resolution is insufficient for the study of dynamic changes of sediment. This paper presents a method of estimating SSC of the Yangtze at Jiujiang using time-series satellite data of high temporal resolution Terra MODIS. It was found that differences in water reflectance between Band 2 and Band 5 could provide relatively accurate SSC estimation even when in-situ atmospheric conditions were unknown. After cross-validation, mean absolute relative error (ARE) and relative root mean square error (RRMSE) were relatively low (i.e., 25.5% and 36.5%, respectively). This empirical relationship was successfully applied to the estimation of SSC at Datong in the Lower Yangtze River, although the SSC values were generally underestimated. This study suggests that Terra MODIS could be used to estimate SSC in large turbid rivers, although some influencing factors require further study to improve the accuracy of SSC estimation.