Discussion of Foster &amp; Brown's Time and Tide: Analysis of Sea Level Time Series

A Parker,C Ollier

doi:10.9734/psij/2015/15652

Abstract

The recognition of the non-accelerating, periodic pattern of sea levels as described by the tide gauges measurements does not require any special mathematical tool. Providing enough data of sufficient quality have been recorded, If the classical linear fitting is used to compute the rate of rise at any time, then the acceleration is simply the time rate of change of this velocity. By using this technique, the lack of any acceleration over the last few decades is evident in the naturally oscillating, slow rising, tide gauges of appropriate quality and length. Contrary to what is claimed in the commented paper, the accuracy in the computation of the periodicities of the natural oscillations does not impact at all on this result. As the measured sea level oscillations are not perfectly sinusoidal, clearly different assumptions about the shape of the periodic functions, their number and the definition of the algorithm used to compute the parameters of the selected periodic functions all affect the determination of the periodicities. This has however very little influence on the present sea level debate questioning the presence or the absence of acceleration at the tide gauges.

Highlights

Analyses of the sea levels recorded by the tide gauges have shown that contrary to the Intergovernmental Panel on Climate Change (IPCC) claim, there has been no sign of carbon dioxide driven acceleration since the 1950
Analyses of the sea levels recorded by the tide gauges have shown that contrary to the IPCC claim, there has been no sign of carbon dioxide driven acceleration since the 1950
The use in different times of different populations of tide gauges of different length, different rates of subsidence or uplift, and different parameters of the oscillations is what permits the false claim the sea level have been accelerating over the last decades by cherry picking when all the long term tide gauges of the world have been on average acceleration free

Summary

Introduction

Analyses of the sea levels recorded by the tide gauges have shown that contrary to the IPCC claim, there has been no sign of carbon dioxide driven acceleration since the 1950. As a matter of fact, the most part of the work on the multi-decadal periodicities claim the existence of quasi-20 or quasi-60 year’s periodicities, and not certainly of perfectly sinusoidal oscillations of time periods computed within an accuracy of the nanoseconds It is shown with a simple methodology as the sea levels are not accelerating and the issues raised by Foster & Brown (2014) are irrelevant. According to [4], the papers that have examined sea level data to estimate the pattern of acceleration and deceleration proposing cyclic or quasi-periodic variations “contain technical problems which call their results into question” In this way, the authors try to make unclear what is otherwise very evident, defocusing the debate from the striding differences from the pattern predicted by the Intergovernmental Panel on Climate Change (IPCC) climate models and the actual measurements at the tide gauges

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