Dynamical geography and transition paths of Sargassum in the tropical Atlantic
Dynamical geography and transition paths of Sargassum in the tropical Atlantic
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DOI：
10.1063/5.0117623
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发表时间：
2022-10-01
期刊：
影响因子：
1.6
通讯作者：
Lumpkin, R.
中科院分区：
文献类型：
--
作者：
Beron-Vera, F. J.;Olascoaga, M. J.;Lumpkin, R.
通过分析一个时间齐次马尔可夫链构建的轨迹undrogued漂流浮标从NOAA全球漂流者计划，我们发现，概率密度可以分布的方式，非常接近最近观察到的经常性带的高马尾藻浓度在热带大西洋之间的5和10度N，创造了大大西洋马尾藻带（GASB）。相关的过渡矩阵的谱分析进一步揭示了一个向前吸引几乎不变的一套在墨西哥湾西北部的吸引力弱连接与马尾藻海，但包括亚马逊河和奥里诺科河河口周围的营养丰富的地区，也上升流系统关闭西非的北方海岸相应的盆地。这是一个基于数据的推断，潜在的远程来源的马尾藻经常入侵美洲内海域（IAS）。通过进一步应用过渡路径理论（TPT）的数据导出的马尔可夫链模型，两个潜在的途径，马尾藻到IAS从非洲海岸的上升流系统揭示。一个TPT推断的途径发生在沿着GASB。第二条路径更向南，速度也更慢，首先穿过几内亚湾，然后穿过热带大西洋到达亚马逊河河口，最后沿着南美洲东北边缘。这样一个南方TPT推断的途径的存在可能会产生后果，从河流径流的营养盐的水华刺激。(C)2022年作者。
By analyzing a time-homogeneous Markov chain constructed using trajectories of undrogued drifting buoys from the NOAA Global Drifter Program, we find that probability density can distribute in a manner that resembles very closely the recently observed recurrent belt of high Sargassum concentration in the tropical Atlantic between 5 and 10 degrees N, coined the Great Atlantic Sargassum Belt (GASB). A spectral analysis of the associated transition matrix further unveils a forward attracting almost-invariant set in the northwestern Gulf of Mexico with a corresponding basin of attraction weakly connected with the Sargasso Sea but including the nutrient-rich regions around the Amazon and Orinoco rivers mouths and also the upwelling system off the northern coast of West Africa. This represents a data-based inference of potential remote sources of Sargassum recurrently invading the Intra-Americas Seas (IAS). By further applying Transition Path Theory (TPT) to the data-derived Markov chain model, two potential pathways for Sargassum into the IAS from the upwelling system off the coast of Africa are revealed. One TPT-inferred pathway takes place along the GASB. The second pathway is more southern and slower, first going through the Gulf of Guinea, then across the tropical Atlantic toward the mouth of the Amazon River, and finally along the northeastern South American margin. The existence of such a southern TPT-inferred pathway may have consequences for bloom stimulation by nutrients from river runoff. (C) 2022 Author(s).