Analysis of riverine suspended particulate matter fluxes (Gulf of Lion, Mediterranean Sea) using a synergy of ocean color observations with a 3-D hydrodynamic sediment transport model
Analysis of riverine suspended particulate matter fluxes (Gulf of Lion, Mediterranean Sea) using a synergy of ocean color observations with a 3-D hydrodynamic sediment transport model
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DOI：
10.1002/2014jc010098
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发表时间：
2015-02
影响因子：
--
通讯作者：
V. L. Fouest;M. Chami;R. Verney
中科院分区：
文献类型：
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作者：
V. L. Fouest;M. Chami;R. Verney
沿海海洋中河流悬浮颗粒物（SPM）的输出对生物地球化学循环具有重要影响。在地中海（法国），罗纳河向狮子湾（GoL）输入的SPM在时间上变化很大，这严重阻碍了SPM通量的评估。本研究的目的是：(i)利用水动力输沙模式与卫星观测的互补（即协同）来研究SPM的陆-海通量预测；（ii）分析SPM输出的空间分布。提出了一种将MARS-3D模型与卫星海洋颜色数据相结合的方法。卫星衍生SPM和光穿透深度用于初始化MARS-3D并验证其预测。通过敏感性分析，量化了河流泥沙粒径组成和沉降速率对泥沙水平出口的影响。在两种条件下，模型与卫星在SPM空间分布和输出方面的一致性最好，即“重而快”沉降颗粒相对于“轻而慢”沉降颗粒的相对比例显著增加，以及“重而轻”SPM沉降速率增加5倍。MARS-3D与卫星数据的协同作用使罗纳河口附近SPM通量预测提高了48%。我们的研究结果证实了在海洋模式初始化过程中实施卫星观测的重要性，因为数据同化技术可能无法处理具有强烈季节性变化的河流洪水。
The export of riverine suspended particulate matter (SPM) in the coastal ocean has major implications for the biogeochemical cycles. In the Mediterranean Sea (France), the Rhone River inputs of SPM into the Gulf of Lion (GoL) are highly variable in time, which severely impedes the assessment of SPM fluxes. The objectives of this study are (i) to investigate the prediction of the land-to-ocean flux of SPM using the complementarity (i.e., synergy) between a hydrodynamic sediment transport model and satellite observations, and (ii) to analyze the spatial distribution of the SPM export. An original approach that combines the MARS-3D model with satellite ocean color data is proposed. Satellite-derived SPM and light penetration depth are used to initialize MARS-3D and to validate its predictions. A sensitivity analysis is performed to quantify the impact of riverine SPM size composition and settling rate on the horizontal export of SPM. The best agreement between the model and the satellite in terms of SPM spatial distribution and export is obtained for two conditions: (i) when the relative proportion of ''heavy and fast'' settling particles significantly increases relative to the ''light and slow'' ones, and (ii) when the settling rate of heavy and light SPM increases by fivefold. The synergy between MARS-3D and the satellite data improved the SPM flux predictions by 48% near the Rhone River mouth. Our results corroborate the importance of implementing satellite observations within initialization procedures of ocean models since data assimilation techniques may fail for river floods showing strong seasonal variability.