Ocean tides have been observed to be changing worldwide for nonastronomical reasons, which can combine with rising mean sea level (MSL) to increase the long‐term impact to coastal regions. Tides can also exhibit variability at shorter timescales, which may be correlated with short‐term variability in MSL. This short‐term coupling may yield higher peak water levels and increased impacts of exceedance events that may be equally significant as long‐term sea level rise. Previous studies employed the tidal anomaly correlation (TAC) method to quantify the sensitivity of tides to MSL fluctuations at long‐period (>20 years) tide gauges in basin‐scale surveys of the Pacific and Atlantic Ocean, finding that TACs exist at most locations. The Indian Ocean also experiences significant sea level rise and tidal variability yet has been less studied due to a sparse network of tide gauges. However, since the beginning of the 21st century, more tide gauges have been established in a wider geographical range, bringing the possibility of better estimates of tidal and MSL variability. Here, we improve the TAC approach, using the ensemble empirical mode decomposition (EEMD) method to analyze tidal amplitudes and sea level at multiple frequency bands, allowing a more effective use of shorter record tide gauges and better understanding of multiple timescales of tidal variability. We apply this approach to 73 tide gauges in the Indian Ocean to better quantify tidal variability in these under‐studied regions, finding that the majority of locations exhibit significant correlations of tides and MSL.

中文翻译：

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基于集合经验模式分解的印度洋潮汐变化多时标分析

由于非天文学原因，全球范围内的海洋潮汐正在发生变化，这可能与平均海平面（MSL）的上升相结合，从而增加了对沿海地区的长期影响。潮汐也可能在较短的时间尺度上表现出变异性，这可能与MSL的短期变异性相关。这种短期耦合可能会产生更高的峰值水位，并增加超出事件的影响，这与长期海平面上升同样重要。以前的研究使用潮汐异常相关（TAC）方法来量化潮汐对太平洋和大西洋海盆尺度调查中长周期（> 20年）潮汐计MSL波动的敏感度，发现TAC存在于大多数位置。印度洋也经历了明显的海平面上升和潮汐变化，但由于潮汐仪的稀疏网络，因此研究较少。但是，自21世纪初以来，在更广阔的地理范围内建立了更多的潮汐仪，带来了更好地估计潮汐和MSL变化的可能性。在这里，我们使用整体经验模式分解（EEMD）方法来分析多个频带上的潮汐振幅和海平面，从而改进TAC方法，从而可以更有效地使用较短的潮汐记录并更好地理解潮汐变化的多个时标。我们将此方法应用于印度洋的73个潮汐仪，以更好地量化这些研究不足区域的潮汐变化，