Accelerated flooding along the US East Coast: On the impact of sea-level rise, tides, storms, the Gulf Stream, and the North Atlantic Oscillations
Accelerated flooding along the US East Coast: On the impact of sea-level rise, tides, storms, the Gulf Stream, and the North Atlantic Oscillations
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DOI：
10.1002/2014ef000252
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发表时间：
2014-08-01
期刊：
影响因子：
8.2
通讯作者：
Atkinson, Larry P.
中科院分区：
文献类型：
--
作者：
Ezer, Tal;Atkinson, Larry P.
最近的研究将哈特拉斯角以北的美国东海岸确定为海平面加速上升（SLR）的“热点”，这里提出的分析表明，该地区也是“加速洪水的热点”。“近年来，从缅因州湾到佛罗里达的大多数沿海地区，轻微潮汐洪水[定义为高于MHHW（平均较高水位）0.3米]的持续时间加快了。1970年以前至1971-1990年期间，年小洪水持续时间的平均增加量与20 h相似，1971-1990年至1991-2013年期间与50 h相似;洪水加速的空间变化与海平面加速的空间变化相似。小洪水的增加可以从SLR和潮差中预测，但极端风暴潮洪水事件（MHHW以上0.9 m）的频率较难预测，并受北大西洋振荡（NAO）的影响。1960年以来的极端风暴潮事件数的振荡周期约为15年，风暴潮事件数的年际变化与NAO指数呈显著正相关。随着海平面上升，与风暴潮无关的洪水事件也会增加。例如，它表明，为期一周的洪水事件，在弗吉尼亚州的诺福克，往往与时期的减少，在佛罗里达目前的运输。结果表明，以前报道的墨西哥湾流（GS）和沿海海平面的年代际变化之间的连接也可能适用于短期变化，因此，洪水预测可能会得到改善，如果GS的影响被考虑。
Recent studies identified the U.S. East Coast north of Cape Hatteras as a "hotspot" for accelerated sea-level rise (SLR), and the analysis presented here shows that the area is also a "hotspot for accelerated flooding." The duration of minor tidal flooding [defined as 0.3 m above MHHW (mean higher high water)] has accelerated in recent years for most coastal locations from the Gulf of Maine to Florida. The average increase in annual minor flooding duration was similar to 20 h fromthe period before 1970 to 1971-1990, and similar to 50 h from 1971-1990 to 1991-2013; spatial variations in acceleration of flooding resemble the spatial variations of acceleration in sea level. The increase in minor flooding can be predicted from SLR and tidal range, but the frequency of extreme storm surge flooding events (0.9 m above MHHW) is less predictable, and affected by the North Atlantic Oscillations (NAO). The number of extreme storm surge events since 1960 oscillates with a period of similar to 15 year and interannual variations in the number of storms are anticorrelated with the NAO index. With higher seas, there are also more flooding events that are unrelated to storm surges. For example, it is demonstrated that week-long flooding events in Norfolk, VA, are often related to periods of decrease in the Florida Current transport. The results indicate that previously reported connections between decadal variations in the Gulf Stream (GS) and coastal sea level may also apply to short-term variations, so flood predictions may be improved if the GS influence is considered.