Detecting and understanding the accelerated sea level rise along the east coast of the United States during recent decades
Detecting and understanding the accelerated sea level rise along the east coast of the United States during recent decades
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检测和了解近几十年来美国东海岸海平面加速上升
DOI：
10.1002/2014jc010305
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发表时间：
2014
影响因子：
--
通讯作者：
W. Han
中科院分区：
文献类型：
--
作者：
J. Kenigson;W. Han
最近在哈特拉斯角和科德角之间发现了海平面加速上升的“热点”。然而，由于可变性，特别是与大西洋数十年振荡（AMO）相关的~60年周期，长期趋势的加速很难与瞬态加速分开。经验模态分解 (EMD) 和集成 EMD (EEMD) 方法已用于隔离振荡并为趋势提供稳健的加速度估计。然而，这些方法在检测海平面加速上升方面的可靠性尚未得到充分测试，特别是考虑到潮汐计记录的长度有限。在这里，EMD 和 EEMD 方法适用于验潮仪观测和合成海平面时间序列，该序列构建为从验潮仪记录中提取的振荡总和以及具有指定加速度的趋势。使用 (E)EMD 分析连续截断的合成数据和观测数据，并根据记录长度生成加速度误差的估计值。一般来说，EEMD 提供比 EMD 更稳定的加速度估计，并且误差随着记录长度的增加而减小，尽管不是单调的。长度超过两个数十年振荡周期的记录比较短的记录提供更好的估计。此外，AMO 可能对近几十年来在热点地区检测到的快速加速做出了重大贡献。这些发现对于改善气候变暖时区域海平面加速的检测具有重要意义。
A “hot spot” of accelerated sea level rise has recently been detected between Cape Hatteras and Cape Cod. The acceleration in the long-term trend, however, is difficult to isolate from transient acceleration due to variability, particularly the ∼60 year cycle associated with the Atlantic Multidecadal Oscillation (AMO). The Empirical Mode Decomposition (EMD) and Ensemble EMD (EEMD) methods have been used to isolate oscillations and provide robust acceleration estimates for the trend. Yet the reliability of these methods in detecting accelerated sea level rise, particularly given the limited lengths of tide gauge records, has not been fully tested. Here, the EMD and EEMD methods are applied to both tide gauge observations and synthetic sea level time series constructed as a sum of oscillations extracted from tide gauge records and trends with prescribed acceleration rates. The successively truncated synthetic and observed data are analyzed with (E)EMD, and estimates of the acceleration error based on the record length are produced. Generally, EEMD provides more stable acceleration estimates than EMD, and the error decreases as the record length increases, although not monotonically. Records exceeding two multidecadal oscillation periods in length provide superior estimates over shorter records. In addition, the AMO may have contributed significantly to the rapid acceleration detected in the hot spot during recent decades. These findings have important implications for improved detection of regional sea level acceleration in a warming climate.