Influence of the El Niño Phenomenon on Shoreline Evolution. Case Study: Callao Bay, Perú
Influence of the El Niño Phenomenon on Shoreline Evolution. Case Study: Callao Bay, Perú
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厄尔尼诺现象对海岸线演变的影响案例研究：秘鲁卡亚俄湾。
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
A. Dastgheib
中科院分区：
文献类型：
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作者：
E. Guzman;C. Ramos;A. Dastgheib
分析河口和河口附近海岸线的长期动态通常依赖于河流泥沙排放的平均（预测）值。然而，这种方法没有考虑低频率的严重事件，如厄尔尼诺（EN），可能对海岸线产生重大影响。虽然EN对洪水和干旱的影响得到了很好的研究，但关于其对沿海地区，特别是对海岸线演变的影响的信息却很少。2017年初，赤道太平洋发生了一次厄尔尼诺现象，秘鲁受到高降水量、极端河流排放和洪水的影响。在这一事件中，在利马区，Rimac河向卡劳湾排放了大量沉积物，海岸线增加了约1公里，表明EN可能对沿海地区产生重大影响。为了探索这些影响，本文通过分析1985-2019年的陆地卫星图像，研究了EN对卡劳湾海岸线演变的影响，以了解海岸线演变并确定海岸线的变化。结果表明，当发生异常EN时（例如，1982-1983年，1997-1998年和2017年），海岸线经历了高加积相比，当一个较小的，或没有EN发生。在这些事件中，一个显着的三角洲的形式在南端的海湾，和波浪作用的沉积物的重新分配，导致附近的海岸线的加积为7公里的河口以北。这表明这些事件对受EN影响的河口附近海岸线的福祉的重要性。
Analyzing the long-term behavior of the coastlines in the vicinity of river mouths and estuaries usually relies on the mean (predicted) values of the sediment discharge from the river. However, this approach does not consider low frequency, severe events, such as El Nino (EN), that can have a large effect on coastlines. While the effects of an EN on flooding and droughts are well studied, little information exists about its effects on coastal zones, and especially on the evolution of coastlines. In early 2017, an EN occurred in the equatorial Pacific Ocean, and the country of Peru was affected with high precipitation levels, and extreme river discharges and flooding. During this event, in the district of Lima, the Rimac River discharged a huge amount of sediment into the Callao Bay, and the shoreline accreted approximately 1 km, demonstrating the significant effects that an EN can have on coastal zones. To explore these effects, this paper studies the influence of an EN on shoreline evolution in the Callao Bay by analyzing Landsat images from 1985–2019 to understand the shoreline evolution and identify changes to the coastline. Results show that when an extraordinary EN occurs (e.g., 1982–1983, 1997–1998, and 2017), the shoreline experiences high accretion compared to when a smaller, or no EN occurs. During these events, a significant delta forms at the south end of the bay, and the redistribution of the accumulated sediment by wave action causes the accretion of the adjacent coastlines for as far as 7 km north of the river mouth. This shows the importance of these events for the wellbeing of coastlines adjacent to river mouths affected by EN.