Multi-scale dynamical analysis (MSDA) of sea level records versus PDO, AMO, and NAO indexes

TL;DR

This study introduces a multi-scale dynamical analysis method using graphical diagrams to interpret tide gauge records and climate oscillation indices, revealing significant decadal and multidecadal oscillations and teleconnections across global sea level data.

Contribution

The paper presents a novel multi-scale dynamical analysis technique that effectively visualizes oscillations and teleconnections in tide gauge records and climate indices at various time scales.

Findings

Oscillations and teleconnections are clearly highlighted at decadal and multidecadal scales.

Tide gauge accelerations oscillate significantly from positive to negative, following PDO, AMO, and NAO patterns.

A prominent quasi 60-70 year natural oscillation influences sea level records.

Abstract

Herein I propose a multi-scale dynamical analysis to facilitate the physical interpretation of tide gauge records. The technique uses graphical diagrams. It is applied to six secular-long tide gauge records representative of the world oceans: Sydney, Pacific coast of Australia; Fremantle, Indian Ocean coast of Australia; New York City, Atlantic coast of USA; Honolulu, U.S. state of Hawaii; San Diego, U.S. state of California; and Venice, Mediterranean Sea, Italy. For comparison, an equivalent analysis is applied to the Pacific Decadal Oscillation (PDO) index and to the Atlantic Multidecadal Oscillation (AMO) index. Finally, a global reconstruction of sea level and a reconstruction of the North Atlantic Oscillation (NAO) index are analyzed and compared: both sequences cover about three centuries from 1700 to 2000. The proposed methodology quickly highlights oscillations and teleconnections among the records at the decadal and multidecadal scales. At the secular time scales tide gauge records present relatively small (positive or negative) accelerations, as found in other studies. On the contrary, from the decadal to the secular scales (up to 110-year intervals) the tide gauge accelerations oscillate significantly from positive to negative values mostly following the PDO, AMO and NAO oscillations. In particular, the influence of a large quasi 60-70 year natural oscillation is clearly demonstrated in these records. The multiscale dynamical evolutions of the rate and of the amplitude of the annual seasonal cycle of the chosen six tide gauge records are also studied.