Decadal sea level variability of the Indian Ocean is studied using long-term tide gauge observations of 17 stations. The existence of close association between Indian Ocean sea level and the global decadal climate modes, such as Pacific Decadal Oscillation (PDO) and/or Atlantic Multidecadal Oscillation (AMO) is revealed in most of the tide gauge data sets. An anti-phase sea level evolution with PDO index is identified in the regions such as west coast of India, east coast of India and the western coast of Australia. Moreover, the PDO related sea level variability is found to be stronger at the tide gauge stations along the west coast of India compared to that along the east coast of India, ruling out the remote forcing from the equatorial Indian Ocean. On the other hand, the tide gauge station at Mumbai with more than 100 years of data shows an in-phase relationship with AMO index on the decadal timescales, whereas such relationship is very weak at the tide gauge station Fremantle where similar long-term data is available. The analysis of sea level pressure (SLP), rainfall and winds over the tropical Indian Ocean indicates existence of strong relationship with AMO especially over the Arabian Sea region, strongly suggesting that the variability observed at the tide gauge station Mumbai may have larger spatial signatures. During the positive phase of AMO, the Arabian Sea region is characterized by large fall in SLP and a strong cross equatorial flow towards the Indian land mass, which are primarily responsible for the positive sea level anomalies (SLAs) at the Mumbai tide gauge station and the adjacent regions and positive rainfall over India.

利用对17个站的长期潮汐仪观测数据，研究了印度洋的十年代海平面变化。大多数潮汐仪数据集都揭示了印度洋海平面与全球年代际气候模式（如太平洋年代际振荡（PDO）和/或大西洋多年代际振荡（AMO））之间的紧密联系。在印度西海岸，印度东海岸和澳大利亚西海岸等地区发现了具有PDO指数的反相位海平面演变。此外，与印度东海岸相比，在印度西海岸的潮汐观测站发现与PDO有关的海平面变化更大，排除了赤道印度洋的遥远强迫。另一方面，孟买的潮汐台站具有100多年的数据，在十年时间尺度上与AMO指数呈同相关系，而潮汐台站弗里曼特尔（Fremantle）具有类似的长期数据，但这种关系非常微弱。对热带印度洋上的海平面压力（SLP），降雨和风的分析表明，与AMO尤其是在阿拉伯海地区的AMO之间存在很强的关系，这强烈表明在潮位计孟买观测到的变化性可能具有较大的空间特征。在AMO的积极阶段，阿拉伯海地区的特征是SLP大幅下降，并且赤道通向印度陆地的强烈横流，