Including the effects of subsurface currents on buoyant particles in Lagrangian particle tracking models: Model development and its application to the study of riverborne plastics over the Louisiana/Texas shelf
Including the effects of subsurface currents on buoyant particles in Lagrangian particle tracking models: Model development and its application to the study of riverborne plastics over the Louisiana/Texas shelf
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DOI：
10.1016/j.ocemod.2021.101879
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发表时间：
2021-11
期刊：
影响因子：
3.2
通讯作者：
Jun‐Hong Liang;Jinliang Liu;M. Benfield;D. Justić;D. Holstein;Bingqing Liu;R. Hetland;D. Kobashi;C. Dong;Weiyuan Dong
中科院分区：
文献类型：
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作者：
Jun‐Hong Liang;Jinliang Liu;M. Benfield;D. Justić;D. Holstein;Bingqing Liu;R. Hetland;D. Kobashi;C. Dong;Weiyuan Dong
我们报道了一种新的基于物理的算法的开发和实现，该算法在拉格朗日粒子跟踪模型中包括了地下电流对浮力粒子的影响，特别是幼虫传输拉格朗日(LTRANS)模型。在上层海洋，由于Ekman平衡等局地效应和热风平衡等大尺度影响，水平流的方向和大小随水深变化。次表层水流改变了弱浮力粒子的平流和扩散，这些粒子可以通过湍流悬浮在海洋表面边界层中。使用路易斯安那州和得克萨斯州大陆架(乳胶架)的后播模型解决方案，研究了来自密西西比河和阿查法拉亚河的河载塑料的运输和命运。模型结果显示，塑料颗粒离开河口后，在乳胶架上方平均向西南方向移动长达四个月，从几百公里过渡到一千多公里。粒子的路径和命运随着粒子大小的变化而变化，较小的粒子移动较慢。此外，浮力较小的颗粒会在更多的近海区域传输更长的距离，并在乳胶架上停留更长的时间。颗粒路径也表现出与乳胶架上循环的季节性周期相关的强烈的季节性周期。模型结果进一步显示，密西西比河和阿查法拉亚河输送的塑料颗粒中，超过50%到达乳胶架的陆地边界，其中超过18%到达路易斯安那州以西的陆地边界，包括德克萨斯州和墨西哥的部分地区。这个模型框架可以用来研究海洋中其他正浮力颗粒物质的传输，如溢油和浮游生物。
We report on the development and implementation of a novel physics-based algorithm that includes the effects of subsurface current on buoyant particles in a Lagrangian particle tracking model, specifically the Larval TRANSport Lagrangian (LTRANS) model. In the upper ocean, the direction and the magnitude of horizontal current change with water depth due to local effects such as the Ekman balance and large-scale influences such as the thermal wind balance. The subsurface current alters both the advection and the dispersion of weakly buoyant particles that could be suspended in the ocean surface boundary layer by turbulence. The transport and fate of riverborne plastics from the Mississippi and Atchafalaya Rivers were examined using a hindcast model solution for the Louisiana and Texas Continental Shelf (LATEX shelf). The model results show that after leaving the river outlets, plastic particles travel on average in a southwestward direction over the LATEX shelf for up to four months, transiting from a few hundred kilometers to more than a thousand kilometers. The pathways and the fate of particles change as a function of the particle size, with smaller particles traveling slower. Also, less buoyant particles transit longer distances over more offshore regions and remain longer on the LATEX shelf. Particle pathways also display a strong seasonal cycle associate with the seasonal cycle of circulation on the LATEX shelf. The model results further reveal that more than 50% of the plastic particles delivered by the Mississippi and Atchafalaya Rivers reach the land boundary of the LATEX shelf, and more than 18% of those reach the land boundary west of Louisiana including Texas and portions of Mexico. This modeling framework can be used to study the transport of other positively buoyant particulate materials in the ocean, such as spilled oil and plankton.