Thursday, December 07, 2017

Is the Sea Level Stable at Aden, Yemen?

This link is to a paper by Parker and Ollier.

Some reports show a rising sea level trend at Aden and Yemen.  P&O say that this is likely due to questionable statistical adjustments. Their conclusion follows.
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The tide gauge record of Aden is a composite derived from 5 distinctive sets of measurements, with the historical data, comprising 4 of these sets, ending in 1969, and the novel measurements with a new tide gauge, starting in 2007. By revising the alignment of the data up to 1969, and neglecting the misaligned new measurements, the sea levels are only very weekly rising at − 0.05 to 0.24 mm/year in Aden over the 20th century.

In Mumbai, the tide gauge record is the composite of 3 distinctive sets of measurements, with the historical data, comprising 2 of these sets, ending in 1994, and the novel measurements with a new tide gauge, starting in 2005. By revising the alignment of the data up to 1994, and neglecting the misaligned new measurements, the sea levels are perfectly stable over the 20th century.

In Karachi, the tide gauge record is the composite of 4 distinctive sets of measurements, with the historical data, comprising 3 of these sets, ending in 1995, and the novel measurements with a new tide gauge, starting in 2007. By revising the alignment of all the data, the sea levels were previously shown in Parker (2016) to be weekly increasing at +0.18 mm/year over the twentieth century.

The sea levels have, therefore, been stable in Aden, as at Karachi and Mumbai, over all the 20th century.

These and other key sites of the Indian Ocean indicate a stable sea level of about zero mm/year over the last 50 years, as shown in Mörner (2007, 2010, 2014, 2015a, b, 2016a, b), Parker and Ollier (2015) and Parker (2016).

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