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【目的】获取准确的水质参数分布情况,进而对水质参数与动力作用复杂的河口水域环境进行综合评价。【方法】利用2011年5月30组长江口水域的遥感反射率数据,在尝试多种波段组合以及不同函数形式后,针对叶绿素a浓度和总悬浮物浓度分别建立最优经验反演模型。【结果】对总悬浮物浓度,波段差值(634~644 nm)的二次函数形式最优,决定系数R2为0.837,均方根误差(RMSE)为0.226 mg·L,利用独立的验证样本得到平均绝对百分比误差(MAPE)为58.2%。对叶绿素a浓度,波段比值(650 nm/644 nm)的二次函数形式最优,为0.552,RMSE为0.486 mg m,利用独立的验证样本得到MAPE为66.2%。将模型运用于2011年5月MERIS卫星数据,反演出长江口水域叶绿素a浓度与总悬浮物浓度空间分布图,叶绿素a浓度呈现出从河口向外海逐渐减少的趋势,最大值出现在舟山群岛附近。总悬浮物浓度呈阶梯状向外海减少。【结论】通过评价参数可看出,总悬浮物浓度反演模型对总悬浮物浓度反演效果较为准确,而叶绿素a浓度反演模型显示对叶绿素a的反演浓度较低。
【Objective】 Obtain accurate distribution of water quality parameters, and then make a comprehensive evaluation of the water quality parameters and the dynamics of the estuarine waters. 【Method】 Based on remote sensing reflectance data of 30 May 2011 watersheds, the optimal empirical inversion model for chlorophyll-a concentration and total suspended matter concentration was established after trying various band combinations and different function forms. 【Result】 The results showed that the quadratic function of total concentration and band difference (634 ~ 644 nm) was the best. The determination coefficient R2 was 0.837 and the root mean square error (RMSE) was 0.226 mg · L. The independent validation samples The average absolute percentage error (MAPE) was 58.2%. For the concentration of chlorophyll a, the quadratic function of the band ratio (650 nm / 644 nm) was 0.552 and the RMSE was 0.486 mg m. MAPE was 66.2% with independent validation samples. Applying the model to MERIS satellite data in May 2011, the spatial distribution of chlorophyll a concentration and total suspended matter concentration in the Yangtze Estuary waters was inverted. The chlorophyll a concentration showed a decreasing trend from the estuary to the outer sea, and the maximum appeared in the Zhoushan Archipelago . The total suspended solids concentration stepped down to the sea. 【Conclusion】 It can be seen from the evaluation parameters that the total suspended sediment concentration inversion model is more accurate for the total suspended sediment concentration inversion, while the chlorophyll a concentration inversion model shows a lower inversion concentration of chlorophyll a.