Coherent patterns in long-term sea-level variability trends derived from long-term tide gauge measurements

2012 ◽  
Vol 33 (3) ◽  
pp. 577-584
Author(s):  
Ivica Vilibić ◽  
Jadranka Šepić ◽  
Zoran Adam Gaxotte
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Sea Level Variability ◽  
Tide Gauge Measurements

scholarly journals Use of Oceanic Reanalysis to Improve Estimates of Extreme Storm Surge

2019 ◽  
Vol 36 (11) ◽  
pp. 2205-2219 ◽  
Author(s):  
Li Zhai ◽  
Blair Greenan ◽  
Richard Thomson ◽  
Scott Tinis
Keyword(s):  
Sea Level ◽  
Storm Surge ◽  
West Coast ◽  
Large Scale ◽  
Tide Gauge ◽  
Steric Effects ◽  
Tide Gauge Records ◽  
The West ◽  
Sea Level Variability

AbstractA storm surge hindcast for the west coast of Canada was generated for the period 1980–2016 using a 2D nonlinear barotropic Princeton Ocean Model forced by hourly Climate Forecast System Reanalysis wind and sea level pressure. Validation of the modeled storm surges using tide gauge records has indicated that there are extensive areas of the British Columbia coast where the model does not capture the processes that determine the sea level variability on intraseasonal and interannual time scales. Some of the discrepancies are linked to large-scale fluctuations, such as those arising from major El Niño and La Niña events. By applying an adjustment to the hindcast using an ocean reanalysis product that incorporates large-scale sea level variability and steric effects, the variance of the error of the adjusted surges is significantly reduced (by up to 50%) compared to that of surges from the barotropic model. The importance of baroclinic dynamics and steric effects to accurate storm surge forecasting in this coastal region is demonstrated, as is the need to incorporate decadal-scale, basin-specific oceanic variability into the estimation of extreme coastal sea levels. The results improve long-term extreme water level estimates and allowances for the west coast of Canada in the absence of long-term tide gauge records data.

scholarly journals Spatial patterns of linear and nonparametric long-term trends in Baltic sea-level variability

2012 ◽  
Vol 19 (1) ◽  
pp. 95-111 ◽  
Author(s):  
R. V. Donner ◽  
R. Ehrcke ◽  
S. M. Barbosa ◽  
J. Wagner ◽  
J. F. Donges ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sea Level ◽  
Spatial Patterns ◽  
Tide Gauge ◽  
Sufficient Information ◽  
Sea Level Variability ◽  
Advantages And Disadvantages ◽  
Long Term Trends ◽  
The Impact

Abstract. The study of long-term trends in tide gauge data is important for understanding the present and future risk of changes in sea-level variability for coastal zones, particularly with respect to the ongoing debate on climate change impacts. Traditionally, most corresponding analyses have exclusively focused on trends in mean sea-level. However, such studies are not able to provide sufficient information about changes in the full probability distribution (especially in the more extreme quantiles). As an alternative, in this paper we apply quantile regression (QR) for studying changes in arbitrary quantiles of sea-level variability. For this purpose, we chose two different QR approaches and discuss the advantages and disadvantages of different settings. In particular, traditional linear QR poses very restrictive assumptions that are often not met in reality. For monthly data from 47 tide gauges from along the Baltic Sea coast, the spatial patterns of quantile trends obtained in linear and nonparametric (spline-based) frameworks display marked differences, which need to be understood in order to fully assess the impact of future changes in sea-level variability on coastal areas. In general, QR demonstrates that the general variability of Baltic sea-level has increased over the last decades. Linear quantile trends estimated for sliding windows in time reveal a wide-spread acceleration of trends in the median, but only localised changes in the rates of changes in the lower and upper quantiles.

scholarly journals Inferring regional vertical crustal velocities from averaged relative sea level trends: A proof of concept

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
H. Bâki Iz ◽  
C. K. Shum ◽  
C. Zhang ◽  
C. Y. Kuo
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Eastern Coast ◽  
Adjustment Process ◽  
Tide Gauge Records ◽  
Relative Sea Level ◽  
Isostatic Adjustment ◽  
Vertical Crustal Motion ◽  
Gps Time Series

AbstractThis study demonstrates that relative sea level trends calculated from long-term tide gauge records can be used to estimate relative vertical crustal velocities in a region with high accuracy. A comparison of the weighted averages of the relative sea level trends estimated at six tide gauge stations in two clusters along the Eastern coast of United States, in Florida and in Maryland, reveals a statistically significant regional vertical crustal motion of Maryland with respect to Florida with a subsidence rate of −1.15±0.15 mm/yr identified predominantly due to the ongoing glacial isostatic adjustment process. The estimate is a consilience value to validate vertical crustal velocities calculated from GPS time series as well as towards constraining predictive GIA models in these regions.

scholarly journals Global sea level reconstruction for 1900–2015 reveals regional variability in ocean dynamics and an unprecedented long weakening in the Gulf Stream flow since the 1990s

Ocean Science ◽  
2020 ◽  
Vol 16 (4) ◽  
pp. 997-1016
Author(s):  
Tal Ezer ◽  
Sönke Dangendorf
Keyword(s):  
Sea Level ◽  
Gulf Stream ◽  
Tide Gauge ◽  
Meridional Overturning Circulation ◽  
Ocean Dynamics ◽  
South Atlantic Bight ◽  
Regional Variability ◽  
Coastal Sea ◽  
Global Sea Level

Abstract. A new monthly global sea level reconstruction for 1900–2015 was analyzed and compared with various observations to examine regional variability and trends in the ocean dynamics of the western North Atlantic Ocean and the US East Coast. Proxies of the Gulf Stream (GS) strength in the Mid-Atlantic Bight (GS-MAB) and in the South Atlantic Bight (GS-SAB) were derived from sea level differences across the GS. While decadal oscillations dominate the 116-year record, the analysis showed an unprecedented long period of weakening in the GS flow since the late 1990s. The only other period of long weakening in the record was during the 1960s–1970s, and red noise experiments showed that is very unlikely that those just occurred by chance. Ensemble empirical mode decomposition (EEMD) was used to separate oscillations at different timescales, showing that the low-frequency variability of the GS is connected to the Atlantic Multi-decadal Oscillation (AMO) and the Atlantic Meridional Overturning Circulation (AMOC). The recent weakening of the reconstructed GS-MAB was mostly influenced by weakening of the upper mid-ocean transport component of AMOC as observed by the RAPID measurements for 2005–2015. Comparison between the reconstructed sea level near the coast and tide gauge data for 1927–2015 showed that the reconstruction underestimated observed coastal sea level variability for timescales less than ∼5 years, but lower-frequency variability of coastal sea level was captured very well in both amplitude and phase by the reconstruction. Comparison between the GS-SAB proxy and the observed Florida Current transport for 1982–2015 also showed significant correlations for oscillations with periods longer than ∼5 years. The study demonstrated that despite the coarse horizontal resolution of the global reconstruction (1∘ × 1∘), long-term variations in regional dynamics can be captured quite well, thus making the data useful for studies of long-term variability in other regions as well.

scholarly journals Atmospheric circulation changes and their impact on extreme sea levels around Australia

2019 ◽  
Vol 19 (5) ◽  
pp. 1067-1086 ◽  
Author(s):  
Frank Colberg ◽  
Kathleen L. McInnes ◽  
Julian O'Grady ◽  
Ron Hoeke
Keyword(s):  
Sea Level ◽  
Large Scale ◽  
Climate Models ◽  
Tide Gauge ◽  
Austral Summer ◽  
Sea Level Changes ◽  
Sea Level Variability ◽  
Sea Levels ◽  
Extreme Sea Levels ◽  
Coastal Sea

Abstract. Projections of sea level rise (SLR) will lead to increasing coastal impacts during extreme sea level events globally; however, there is significant uncertainty around short-term coastal sea level variability and the attendant frequency and severity of extreme sea level events. In this study, we investigate drivers of coastal sea level variability (including extremes) around Australia by means of historical conditions as well as future changes under a high greenhouse gas emissions scenario (RCP 8.5). To do this, a multi-decade hindcast simulation is validated against tide gauge data. The role of tide–surge interaction is assessed and found to have negligible effects on storm surge characteristic heights over most of the coastline. For future projections, 20-year-long simulations are carried out over the time periods 1981–1999 and 2081–2099 using atmospheric forcing from four CMIP5 climate models. Changes in extreme sea levels are apparent, but there are large inter-model differences. On the southern mainland coast all models simulated a southward movement of the subtropical ridge which led to a small reduction in sea level extremes in the hydrodynamic simulations. Sea level changes over the Gulf of Carpentaria in the north are largest and positive during austral summer in two out of the four models. In these models, changes to the northwest monsoon appear to be the cause of the sea level response. These simulations highlight a sensitivity of this semi-enclosed gulf to changes in large-scale dynamics in this region and indicate that further assessment of the potential changes to the northwest monsoon in a larger multi-model ensemble should be investigated, together with the northwest monsoon's effect on extreme sea levels.

Very-Long-Baseline Interferometry Applied to Geophysics

1993 ◽  
Vol 156 ◽  
pp. 133-144
Author(s):  
W. E. Carter ◽  
D. S. Robertson
Keyword(s):  
Very Long Baseline Interferometry ◽  
Tide Gauge ◽  
Global Changes ◽  
Long Baseline ◽  
Tidal Forces ◽  
The Earth ◽  
Tide Gauge Measurements ◽  
Rotation Of The Earth ◽  
Global Reference Frame

Very-long-baseline Interferometry (VLBI) has opened for study a broad new spectrum of geophysical phenomena including: direct observation of the tectonic motions and deformations of the Earth's crustal plates, observations of unprecedented detail of the variations in the rotation of the Earth, and direct measurement of the elastic deformations of the Earth in response to tidal forces. These new measurements have placed significant constraints on models of the interior structure of the Earth; for example, measurements of the variations in the Earth's nutation have been shown to be particularly sensitive to the shape of the core-mantle boundary. The VLBI measurements will allow us to construct a global reference frame accurate at the centimeter level. Such a frame will be essential to studying long-term global changes, especially those changes related to sea-level variations as recorded by tide gauge measurements.

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