Sea-level variations from co-located tide gauge and GNSS stations using GNSS-Reflectometry in Indonesia

Abstract. The city of Venice and the surrounding lagoonal ecosystem are highly vulnerable to variations in relative sea level. In the past ∼150 years, this was characterized by an average rate of relative sea-level rise of about 2.5 mm/year resulting from the combined contributions of vertical land movement and sea-level rise. This literature review reassesses and synthesizes the progress achieved in quantification, understanding and prediction of the individual contributions to local relative sea level, with a focus on the most recent studies. Subsidence contributed to about half of the historical relative sea-level rise in Venice. The current best estimate of the average rate of sea-level rise during the observational period from 1872 to 2019 based on tide-gauge data after removal of subsidence effects is 1.23 ± 0.13 mm/year. A higher – but more uncertain – rate of sea-level rise is observed for more recent years. Between 1993 and 2019, an average change of about +2.76 ± 1.75 mm/year is estimated from tide-gauge data after removal of subsidence. Unfortunately, satellite altimetry does not provide reliable sea-level data within the Venice Lagoon. Local sea-level changes in Venice closely depend on sea-level variations in the Adriatic Sea, which in turn are linked to sea-level variations in the Mediterranean Sea. Water mass exchange through the Strait of Gibraltar and its drivers currently constitute a source of substantial uncertainty for estimating future deviations of the Mediterranean mean sea-level trend from the global-mean value. Regional atmospheric and oceanic processes will likely contribute significant interannual and interdecadal future variability in Venetian sea level with a magnitude comparable to that observed in the past. On the basis of regional projections of sea-level rise and an understanding of the local and regional processes affecting relative sea-level trends in Venice, the likely range of atmospherically corrected relative sea-level rise in Venice by 2100 ranges between 32 and 62 cm for the RCP2.6 scenario and between 58 and 110 cm for the RCP8.5 scenario, respectively. A plausible but unlikely high-end scenario linked to strong ice-sheet melting yields about 180 cm of relative sea-level rise in Venice by 2100. Projections of human-induced vertical land motions are currently not available, but historical evidence demonstrates that they have the potential to produce a significant contribution to the relative sea-level rise in Venice, exacerbating the hazard posed by climatically induced sea-level changes.

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Impact of sea level variations on hydrographic survey around Taiwan

10.5194/egusphere-egu2020-13544 ◽

2020 ◽

Author(s):

Wen-Hau Lan ◽

Chung-Yen Kuo ◽

Sheng-Fong Lin ◽

Chien-Hsing Lu

Keyword(s):

Sea Level ◽

Tide Gauge ◽

Temporal Changes ◽

Altimeter Data ◽

Ocean Tide ◽

Ocean Tides ◽

Sea Level Anomalies ◽

Sea Level Variations ◽

Ocean Tide Models ◽

And Sea Level

Taiwan is an island entirely surrounded by oceans, so living and economics are significantly influenced by the oceans. The electronic navigational chart system is extremely important for improving the safety of marine navigation and ocean depth is the essential data for electronic charts. Sea surface variations affected by ocean tide and sea level change are the main error sources in hydrographic surveys since the traditional tidal correction only using tide gauge stations, ignoring geographically non-uniform ocean tides and sea level anomalies around Taiwan. In this research, we evaluate two factors impacting the accuracy of hydrographic surveys, including ocean tides and seasonal sea level variations, using tide gauge records, satellite altimeter data and ocean tide models around Taiwan, and also analyze the accuracy of the ocean tide models around Taiwan. In addition, sea level anomalies are strongly influenced by climate changes in recent years. An understanding of seasonal sea level cycle and its spatial and temporal changes are importance because its temporal changes can result in the variation of the frequency and magnitude of coastal hazards. Therefore, we will apply the Ensemble Empirical Mode Decomposition to sea level data to assess the stability of the long-term seasonal sea level fluctuations with time.

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Evaluation and improvement of coastal GNSS reflectometry sea level variations from existing GNSS stations in Taiwan

Advances in Space Research ◽

10.1016/j.asr.2018.10.039 ◽

2019 ◽

Vol 63 (3) ◽

pp. 1280-1288 ◽

Cited By ~ 2

Author(s):

Chi-Ming Lee ◽

Chung-Yen Kuo ◽

Jian Sun ◽

Tzu-Pang Tseng ◽

Kwo-Hwa Chen ◽

...

Keyword(s):

Sea Level ◽

Gnss Reflectometry ◽

Sea Level Variations

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Tide gauge-based sea level variations since 1950 along the Norwegian and Russian coasts of the Arctic Ocean: Contribution of the steric and mass components

Journal of Geophysical Research Atmospheres ◽

10.1029/2011jc007706 ◽

2012 ◽

Vol 117 (C6) ◽

pp. n/a-n/a ◽

Cited By ~ 28

Author(s):

O. Henry ◽

P. Prandi ◽

W. Llovel ◽

A. Cazenave ◽

S. Jevrejeva ◽

...

Keyword(s):

Arctic Ocean ◽

Sea Level ◽

Tide Gauge ◽

The Arctic ◽

The Arctic Ocean ◽

Sea Level Variations

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Sea level accelerations at globally distributed tide gauge stations during the satellite altimetry era

Journal of Geodetic Science ◽

10.1515/jogs-2018-0013 ◽

2018 ◽

Vol 8 (1) ◽

pp. 130-135 ◽

Cited By ~ 1

Author(s):

H. Bâki Iz ◽

C. K. Shum ◽

C. Y. Kuo

Keyword(s):

Sea Level ◽

Satellite Altimetry ◽

Tide Gauge ◽

Tide Gauge Data ◽

Trend Model ◽

Gauge Data ◽

Sea Level Variations ◽

Global Mean Sea Level ◽

Globally Distributed ◽

Global Mean

Abstract This observational study reports that several globally distributed tide gauge stations exhibit a propensity of statistically significant sea level accelerations during the satellite altimetry era. However, the magnitudes of the estimated tide gauge accelerations during this period are systematically and noticeably smaller than the global mean sea level acceleration reported by recent analyses of satellite altimetry. The differences are likely to be caused by the interannual, decadal and interdecadal sea level variations, which are modeled using a broken trend model with overlapping harmonics in the analyses of tide gauge data but omitted in the analysis of satellite altimetry.

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Linear and non-linear sea-level variations in the Adriatic Sea from tide gauge records (1872-2012)

Annals of Geophysics ◽

10.4401/ag-6536 ◽

2015 ◽

Vol 57 (6) ◽

Author(s):

Gaia Galassi ◽

Giorgio Spada

Keyword(s):

Sea Level ◽

North Atlantic ◽

Adriatic Sea ◽

Tide Gauge ◽

Ensemble Empirical Mode Decomposition ◽

Tide Gauges ◽

Tide Gauge Records ◽

Mode Decomposition ◽

Sea Level Variations ◽

Global Values

We have analyzed tide gauge data from the Adriatic Sea in order to assess the secular sea-level trend, its acceleration and the existence of possible cyclic variation. Analyzing the sea-level stack of all Adriatic tide gauges, we have obtained a trend of (1.25±0.04) mm yr-1, in agreement with that observed for the last century in the Mediterranean Sea, and an acceleration that is negligibile compared to the average global values. By means of the Ensemble Empirical Mode Decomposition technique, we have evidenced an energetic oscillation with a period of ∼20 years that we relate with the recurrence of opposite phases in the Atlantic Multi–decadal Oscillation and North Atlantic Oscillation indices. We suggest that anomalously high sea-level values observed at all the Adriatic tide gauges during 2010 and 2011 can be explained by the rising phase of this 20 years cycle.

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Why and how to predict sea level changes at a tide gauge station with prediction intervals

Journal of Geodetic Science ◽

10.1515/jogs-2018-0012 ◽

2018 ◽

Vol 8 (1) ◽

pp. 121-129

Author(s):

H. Bâki Iz

Keyword(s):

Sea Level ◽

Policy Development ◽

Tide Gauge ◽

Prediction Intervals ◽

Sea Level Changes ◽

Mitigation And Adaptation ◽

Coastal Risk Assessment ◽

Sea Level Variations ◽

Coastal Risk ◽

Globally Distributed

Abstract Predicting sea level rise is essential for current climate discussions. Empirical models put in use to monitor and analyze sea level variations observed at globally distributed tide gauge stations during the last decade can provide reliable predictions with high resolution. Meanwhile, prediction intervals, an alternative to confidence intervals, are to be recognized and deployed in sea level studies. Predictions together with their prediction intervals, as demonstrated in this study, can quantify the uncertainty of a single future observation from a population, instead of the uncertainty of a conceivable average sea level namely a confidence interval, and it is thereby, better suited for coastal risk assessment to guide policy development for mitigation and adaptation responses.

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The effect of regional sea level atmospheric pressure on sea level variations at globally distributed tide gauge stations with long records

Journal of Geodetic Science ◽

10.1515/jogs-2018-0007 ◽

2018 ◽

Vol 8 (1) ◽

pp. 55-71 ◽

Cited By ~ 1

Author(s):

H. Bâki Iz

Keyword(s):

Sea Level ◽

Atmospheric Pressure ◽

Tide Gauge ◽

Atmospheric Temperature ◽

Random Component ◽

Sea Level Changes ◽

Additional Information ◽

Sea Level Variations ◽

The Impact ◽

Globally Distributed

Abstract This study provides additional information about the impact of atmospheric pressure on sea level variations. The observed regularity in sea level atmospheric pressure depends mainly on the latitude and verified to be dominantly random closer to the equator. It was demonstrated that almost all the annual and semiannual sea level variations at 27 globally distributed tide gauge stations can be attributed to the regional/local atmospheric forcing as an inverted barometric effect. Statistically significant non-linearities were detected in the regional atmospheric pressure series, which in turn impacted other sea level variations as compounders in tandem with the lunar nodal forcing, generating lunar sub-harmonics with multidecadal periods. It was shown that random component of regional atmospheric pressure tends to cluster at monthly intervals. The clusters are likely to be caused by the intraannual seasonal atmospheric temperature changes,which may also act as random beats in generating sub-harmonics observed in sea level changes as another mechanism. This study also affirmed that there are no statistically significant secular trends in the progression of regional atmospheric pressures, hence there was no contribution to the sea level trends during the 20th century by the atmospheric pressure.Meanwhile, the estimated nonuniform scale factors of the inverted barometer effects suggest that the sea level atmospheric pressure will bias the sea level trends inferred from satellite altimetry measurements if their impact is accounted for as corrections without proper scaling.

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