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

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.

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

2018 ◽  
Vol 8 (1) ◽  
pp. 55-71 ◽  
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.

scholarly journals Thermosteric contribution of warming oceans to the global sea level variations

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
H. Bâki Iz
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Secular Trends ◽  
Sea Surface ◽  
Sea Level Changes ◽  
Long Period ◽  
Sea Level Variations ◽  
Global Sea Level ◽  
Almost All ◽  
Globally Distributed

AbstractThermosteric contribution of warming oceans to the global sea level variations during the last century was evaluated at globally distributed 27 tide gauge stations with records over 80 years. The assessment was made using a recently proposed lagged model inclusive of a sea level trend, long and decadal periodicities, and lagged sea surface temperature measurements. The new model solutions revealed that almost all the long period periodic sea level changes experienced at these stations can be attributed to the lagged thermosteric effects of the warming oceans during the 20th century. Meanwhile, statistically significant (p<0.05) anomalous thermosteric contributions to the secular trends, some of them as large as 1.0±0.2 mm/yr, were detected at six tide gauge stations close to the equator and open seas. The findings of this study revealed a more complex impact of the warming oceans at the globally distributed tide gauge stations other than a secular contribution to the sea level trends of the previous studies.

scholarly journals Sea-level rise in Venice: historic and future trends (review article)

2021 ◽  
Vol 21 (8) ◽  
pp. 2643-2678 ◽  
Author(s):  
Davide Zanchettin ◽  
Sara Bruni ◽  
Fabio Raicich ◽  
Piero Lionello ◽  
Fanny Adloff ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Tide Gauge ◽  
Average Rate ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
The Past ◽  
Gauge Data ◽  
Relative Sea Level Rise ◽  
Sea Level Variations

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.

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

2018 ◽  
Vol 8 (1) ◽  
pp. 130-135 ◽  
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.

scholarly journals Rekonstruiranje promjena morske razine na istočnoj obali Jadrana (Hrvatska) – pregled

Geoadria ◽  
2017 ◽  
Vol 14 (2) ◽  
pp. 181 ◽  
Author(s):  
Maša Surić
Keyword(s):  
Sea Level ◽  
Multidisciplinary Approach ◽  
Tide Gauge ◽  
Tidal Range ◽  
Research Progress ◽  
Sea Level Changes ◽  
Historical Evidence ◽  
Adriatic Coast ◽  
Sea Level Variations ◽  
Methodological Approaches

Rocky karstified coast, low tidal range, indented shoreline with numerous islands, diverse coastal biocenoses, abundant palaeontological, archaeological and historical evidence, relatively dense tide-gauge stations and developing GPS network – all these facts offer optimal prerequisite for the sea-level changes studies on the Croatian coast. Through various methodological approaches (geomorphological, biostratigraphical, archaeological/historical, mareographic, geodetic, radiometric), most of these issues have been used in order to reconstruct relative sea and land motions, yielding scattered and sometimes erroneous results. Unfortunately, some of them have been often uncritically used as the basis for the subsequent research. Only recently, with multidisciplinary approach, sequences of relative sea-level variations have been successfully revealed, but opportunities that eastern Adriatic coast offers will, undoubtedly, ensure relatively rapid research progress.

Global sea level trends in the presence of variable sea level velocities, and variable accelerations

2013 ◽  
Vol 3 (2) ◽  
pp. 127-135
Author(s):  
H. Bâki Iz ◽  
X.L. Ding ◽  
C.K. Shum
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Linear Representation ◽  
Significant Variable ◽  
Sea Level Changes ◽  
All Solutions ◽  
Acceleration Model ◽  
Serial Correlations ◽  
Global Sea Level ◽  
Globally Distributed

Abstract This study investigates, using a new variable-acceleration model, the validity of the implicit assertion in previous studies regarding global constant sea level rise accelerations. Thirteen out of twenty seven globally distributed tide gauge stations, with records longer than 80 years, exhibit statistically significant quartic coefficients (p < 0.05) revealing the presence of variable sea level accelerations though not as a global phenomenon. Most of these stations initially exhibit decreasing negative velocities until early 20th century and increasing positive velocities after 1970’s following a period of constant velocities. It is shown that, for those locations experiencing statistically significant variable sea level accelerations, the estimates based on the conventional linear representation of linear sea level trends are not appropriate, and are notably biased for a number of stations. All solutions account for serial correlations, which otherwise induce biases in solution statistics. It is also demonstrated that the omission of non-linearities in sea level changes will bias the sea level trends for short records, such as those from satellite altimetry, as large as 3 mm/yr.

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