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>

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

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 Decadal Sea Level Variability in the Pacific Ocean: Origins and Climate Mode Contributions

2019 ◽  
Vol 36 (4) ◽  
pp. 689-698 ◽  
Author(s):  
Lingsheng Meng ◽  
Wei Zhuang ◽  
Weiwei Zhang ◽  
Angela Ditri ◽  
Xiao-Hai Yan
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Time Scales ◽  
Wind Stress ◽  
Tropical Pacific ◽  
Central Basin ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Sea Level Variations ◽  
The Tropical Pacific

AbstractSea level changes within wide temporal–spatial scales have great influence on oceanic and atmospheric circulations. Efforts have been made to identify long-term sea level trend and regional sea level variations on different time scales. A nonuniform sea level rise in the tropical Pacific and the strengthening of the easterly trade winds from 1993 to 2012 have been widely reported. It is well documented that sea level in the tropical Pacific is associated with the typical climate modes. However, sea level change on interannual and decadal time scales still requires more research. In this study, the Pacific sea level anomaly (SLA) was decomposed into interannual and decadal time scales via an ensemble empirical mode decomposition (EEMD) method. The temporal–spatial features of the SLA variability in the Pacific were examined and were closely associated with climate variability modes. Moreover, decadal SLA oscillations in the Pacific Ocean were identified during 1993–2016, with the phase reversals around 2000, 2004, and 2012. In the tropical Pacific, large sea level variations in the western and central basin were a result of changes in the equatorial wind stress. Moreover, coherent decadal changes could also be seen in wind stress, sea surface temperature (SST), subtropical cells (STCs), and thermocline depth. Our work provided a new way to illustrate the interannual and decadal sea level variations in the Pacific Ocean and suggested a coupled atmosphere–ocean variability on a decadal time scale in the tropical region with two cycles from 1993 to 2016.

scholarly journals Long-term regional trend and variability of mean sea level during the satellite altimetry era

2019 ◽  
Vol 83 (2) ◽  
pp. 111
Author(s):  
Quang-Hung Luu ◽  
Qing Wu ◽  
Pavel Tkalich ◽  
Ge Chen
Keyword(s):  
Sea Level ◽  
Climatic Factors ◽  
Sea Level Change ◽  
Climate System ◽  
Regional Trend ◽  
Mean Sea Level ◽  
Level Change ◽  
The Pacific ◽  
Change In Mean

The rise and fall of mean sea level are non-uniform around the global oceans. Their long-term regional trend and variability are intimately linked to the fluctuations and changes in the climate system. In this study, geographical patterns of sea level change derived from altimetric data over the period 1993-2015 were partitioned into large-scale oscillations allied with prevailing climatic factors after an empirical orthogonal function analysis. Taking into account the El Niño–Southern Oscillation (ENSO) and the Pacific Decadal Oscillations (PDO), the sea level change deduced from the multiple regression showed a better estimate than the simple linear regression thanks to significantly larger coefficients of determination and narrower confidence intervals. Regional patterns associated with climatic factors varied greatly in different basins, notably in the eastern and western regions of the Pacific Ocean. The PDO exhibited a stronger impact on long-term spatial change in mean sea level than the ENSO in various parts of the Indian and Pacific Oceans, as well as of the subtropics and along the equator. Further improvements in the signal decomposition technique and physical understanding of the climate system are needed to better attain the signature of climatic factors on regional mean sea level.

scholarly journals Pacific Sea Levels Rising Very Slowly and Not Accelerating

2019 ◽  
Vol 38 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Albert Parker ◽  
Clifford Ollier
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Relative Rate ◽  
Tide Gauges ◽  
Sea Levels ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Long Term Trend

AbstractOver the past decades, detailed surveys of the Pacific Ocean atoll islands show no sign of drowning because of accelerated sea-level rise. Data reveal that no atoll lost land area, 88.6% of islands were either stable or increased in area, and only 11.4% of islands contracted. The Pacific Atolls are not being inundated because the sea level is rising much less than was thought. The average relative rate of rise and acceleration of the 29 long-term-trend (LTT) tide gauges of Japan, Oceania and West Coast of North America, are both negative, −0.02139 mm yr−1and −0.00007 mm yr−2respectively. Since the start of the 1900s, the sea levels of the Pacific Ocean have been remarkably stable.

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