scholarly journals Barotropic Rossby Waves Radiating from Tropical Instability Waves in the Pacific Ocean

2011 ◽  
Vol 41 (6) ◽  
pp. 1160-1181 ◽  
Author(s):  
J. Thomas Farrar
Keyword(s):  
Dispersion Relation ◽  
Pacific Ocean ◽  
Sea Level ◽  
Rossby Waves ◽  
North Pacific Subtropical Gyre ◽  
Sea Level Variability ◽  
Instability Waves ◽  
Tropical Instability Waves ◽  
The Pacific ◽  
The Pacific Ocean

Abstract Tropical instability waves are triggered by instabilities of the equatorial current systems, and their sea level signal, with peak amplitude near 5°N, is one of the most prominent features of the dynamic topography of the tropics. Cross-spectral analysis of satellite altimetry observations shows that there is sea level variability in the Pacific Ocean as far north as Hawaii (i.e., 20°N) that is coherent with the sea level variability near 5°N associated with tropical instability waves. Within the uncertainty of the analysis, this off-equatorial variability obeys the dispersion relation for nondivergent, barotropic Rossby waves over a fairly broad range of periods (26–38 days) and zonal wavelengths (9°–23° of longitude) that are associated with tropical instability waves. The dispersion relation and observed wave properties further suggest that the waves are carrying energy away from the instabilities toward the North Pacific subtropical gyre, which, together with the observed coherence of the sea level signal of the barotropic waves with that of the tropical instability waves, suggests that the barotropic Rossby waves are being radiated from the tropical instability waves. The poleward transport of kinetic energy and westward momentum by these barotropic Rossby waves may influence the circulation in the subtropics.

scholarly journals Tidal Variability Related to Sea Level Variability in the Pacific Ocean

2017 ◽  
Vol 122 (11) ◽  
pp. 8445-8463 ◽  
Author(s):  
Adam T. Devlin ◽  
David A. Jay ◽  
Edward D. Zaron ◽  
Stefan A. Talke ◽  
Jiayi Pan ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Sea Level Variability ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Tidal Variability

How much of the decadal, coastal sea level variability can we describe by climate modes?

2021 ◽  
Author(s):  
Samantha Royston ◽  
Jonathan Bamber ◽  
Rory Bingham
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Sea Level Change ◽  
Internal Variability ◽  
Sea Level Variability ◽  
Steric Sea Level ◽  
Climate Modes ◽  
Level Change ◽  
The Pacific ◽  
The Pacific Ocean

<p>It is well known that key climatic variability like the El Niño Southern Oscillation and Pacific Decadal Oscillation dominate steric sea-level variability in the Pacific Ocean and that this variability influences global- and regional-mean sea-level time series. Reducing the known internal variability from these time series reduces trend errors and can elucidate other factors including anthropogenic influence and sea-level acceleration, as has been demonstrated for the open ocean. Here we discuss the influence of key climate modes on coastal, decadal sea-level variability. For coastal stakeholders and managers it is important to understand the decadal-scale and local changes in the rate of sea-level rise in the context of internal variability in order to inform management decisions in the short- to medium-term. We use a 53-year run of a high-resolution NEMO ocean model run, forced by the DRAKKAR reanalysis atmospheric data set and with the global-mean sea level at each timestep removed, to investigate modes of decadal sea-level variability at the coast, in different basins and from different sea-level components. At more than 45% of Pacific Ocean coastal locations, greater than 50% of the decadal sea-level change can be explained by a regression of the leading principal component mode with key climate indices; ENSO in the Pacific Ocean. In different ocean basins, 18.5% to 61.0% of coastal locations have more than 33% of decadal sea-level variance explained by our climate index reconstructions. These areas include coastal regions lacking long-duration or good quality tide gauges for long-term observations such as the North-West Africa coastline. Because of the shallow depth of continental shelves, steric sea-level change propagates onto the shelf as a manometric (mass) sea-level signal. We use a set of tide gauge locations to demonstrate the internal, decadal sea-level change observed at many coasts has a substantial contribution from local, manometric signal that is driven by climate variability.</p>

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