Background

The sea level records since the start of the twentieth century show oscillations with many periodicities up to multi-decadal. The sea level may then change because of local factors such as subsidence or uplift, and global factors such as mass addition and thermal expansion of the oceans.

Purpose

We use non-aligned data from the tide gauges of Aden, and the tide gauges of Mumbai and Karachi, to reconstruct the most likely pattern of sea levels for these three locations of the west Indian Ocean.

Methods

Linear and parabolic fittings of monthly average mean sea levels (MSL) from the different tide gauges of the three locations were carried out. Alignment of the different data sets based on historical information, similarity of patterns, and break point alignment was done.

Results

Analysis of the tide gauge data of Aden, Yemen shows that without arbitrary alignment of data, Aden exhibits very stable sea level conditions like those in Mumbai, India and Karachi, Pakistan, without any significant sea level trend.

Conclusion

The reconstructed tide gauge records of Aden, Mumbai and Karachi are perfectly consistent with multiple lines of evidence from other key sites of the Indian Ocean including Qatar, Maldives, Bangladesh and Visakhapatnam. The sea levels have been stable since the start of the twentieth century in Aden similar to Karachi and Mumbai.