scholarly journals Nonlinear absolute sea-level patterns in the long-term-trend tide gauges of the West Coast of North America

2020 ◽  
Vol 9 (1) ◽  
pp. 382-397
Author(s):  
Alberto Boretti
Keyword(s):  
North America ◽  
Sea Level ◽  
West Coast ◽  
Tide Gauge ◽  
Relative Rate ◽  
Tide Gauges ◽  
The West ◽  
The Absolute ◽  
Long Term Trend

AbstractThe research issue of which are the present relative and absolute rates of rise and accelerations for North America is here addressed. The data of the 20 long-term-trend (LTT) tide stations of the West Coast of North America with more than 80 years of recorded data are shown. The absolute rates of rise are computed by considering the absolute vertical velocity of Global Navigation Satellite System (GNSS) antennas near the tide gauges, and the relative rate of sea-level rise from the tide gauge signals. The 20 LTT stations along the West Coast of North America show an average relative rate of rise of -0.38 mm/yr., an average acceleration of +0.0012 mm/yr2, and an average absolute rate of rise of +0.73 mm/yr. This is the first paper publishing a comprehensive survey of the absolute sea-level rates of rise along the West Coast of North America using the reliable information of relative sea-level rates of rise from LTT tide gauges plus the absolute subsidence rates from different GNSS antennas close to the tide gauge installations.

scholarly journals Nonlinear absolute sea-level patterns in the long-term-trend tide gauges of the East Coast of North America

2021 ◽  
Vol 10 (1) ◽  
pp. 1-15
Author(s):  
Alberto Boretti
Keyword(s):  
North America ◽  
Sea Level ◽  
East Coast ◽  
Tide Gauge ◽  
Tide Gauges ◽  
Sea Levels ◽  
Term Trend ◽  
The Absolute ◽  
Long Term Trend

Abstract The paper provides an estimate of the latest relative and absolute rates of rise and accelerations of the sea levels for the East Coast of North America. The computation is based on the long-term trend (LTT) tide gauge records of the relative sea levels and the Global Navigation Satellite System (GNSS) time series of the absolute position of fixed dome nearby the tide gauges. The GNSS result is used to infer the subsidence or uplift of the tide gauge instrument. The data of 33 LTT tide stations with more than 80 years of data are shown. The average relative sea-level rise is +2.22 mm/yr. subjected to a small, positive average acceleration of +0.0027 mm/yr2. The average absolute velocity of the tide gauge instruments is −0.52 mm/yr. translating in an average absolute sea-level rise of +1.70 mm/yr. This is the first paper publishing a comprehensive survey of the absolute sea-level rates of rise along the East Coast of North America using the reliable information of relative sea-level rates of rise from LTT tide gauges, plus the absolute subsidence rates from GNSS antennas that are close to the tide gauges installations.

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.

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.

Origin Time of the 1854 Ansei–Tokai Tsunami Estimated from Tide Gauge Records on the West Coast of North America

2020 ◽  
Vol 91 (5) ◽  
pp. 2624-2630 ◽  
Author(s):  
Satoshi Kusumoto ◽  
Kentaro Imai ◽  
Ryoko Obayashi ◽  
Takane Hori ◽  
Narumi Takahashi ◽  
...  
Keyword(s):  
North America ◽  
San Francisco ◽  
Local Time ◽  
West Coast ◽  
San Diego ◽  
Arrival Time ◽  
Tide Gauge ◽  
The West ◽  
Origin Time ◽  
Tsunami Signal

Abstract We estimated the origin time of the 1854 Ansei–Tokai tsunami from the tsunami waveforms recorded at three tide gauge stations (Astoria, San Francisco, and San Diego) on the west coast of North America. The tsunami signal is apparent in the San Francisco and San Diego records, and the arrival time was 0–1 p.m. Greenwich Mean Time (GMT) on 23 December 1854, whereas the tsunami signal of Astoria is ambiguous, and the arrival time could not be determined from the waveform. The simulated waveforms on the basis of nonlinear dispersive wave theory by assuming an origin time of 0 a.m. GMT on 23 December arrived earlier than the observations. Cross-correlation functions between the observed and simulated waveforms recorded at San Francisco and San Diego showed a time gap between them of approximately 30 min. Based on these results, we concluded that the origin time of the 1854 Ansei–Tokai tsunami was approximately 00:30 a.m. GMT or 09:46 local time on 23 December. Our result is roughly consistent with reports by a Russian frigate anchored in Shimoda Bay, ranging the earthquake between 09:00 and 09:45 and the tsunami between 09:30 and 10:00. The earthquake was also reported in historical Japanese documents ranging from 8 and 10 o’clock in local time.

scholarly journals Assessment of Sea Level Rise at West Coast of Portugal Mainland and Its Projection for the 21st Century

2019 ◽  
Author(s):  
Carlos Antunes
Keyword(s):  
Time Series ◽  
Sea Level Rise ◽  
Sea Level ◽  
21St Century ◽  
West Coast ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
The West ◽  
Relative Sea Level ◽  
Global Sea Level

Data collected at the Cascais tide gauge, located on the west coast of Portugal Mainland, have been analyzed and sea level rise rates have been updated. Based on a bootstrapping linear regression model and on polynomial adjustments, time series are used to calculate different empirical projections for the 21st century sea level rise, by estimating the initial velocity and its corresponding acceleration. The results are consistent to an accelerated sea level rise, showing evidence of a faster rise than previous century estimates. Based on different numerical methods of second order polynomial fitting, it is possible to build a set of projection models of relative sea level rise. Appling the same methods to regional sea level anomaly from satellite altimetry, additional projections are also built with good consistency. Both data sets, tide gauge and satellite altimetry data, enabled the development of an ensemble of projection models. The relative sea level rise projections are crucial for national coastal planning and management since extreme sea level scenarios can potentially cause erosion and flooding. Based on absolute vertical velocities obtained by integrating global sea level models, neo-tectonic studies and permanent Global Positioning System (GPS) station time series, it is possible to transform relative into absolute sea level rise scenarios, and vice-versa, allowing the generation of absolute sea level rise projection curves and its comparison with already established global projections. The sea level rise observed at the Cascais tide gauge has always shown a significant correlation with global sea level rise observations, evidencing relatively low rates of composed vertical land velocity from tectonic and post-glacial isostatic adjustment, and residual synoptic regional dynamic effects rather than a trend. An ensemble of sea level projection models for the 21st century is proposed with its corresponding probability density function, both for relative and absolute sea level rise for the west coast of Portugal Mainland.

scholarly journals Tide and mean sea level trend in the west coast of the Arabian Gulf from tide gauges and multi-missions satellite altimeter

Oceanologia ◽  
2019 ◽  
Vol 61 (4) ◽  
pp. 401-411 ◽  
Author(s):  
Nada Abdulraheem Siddig ◽  
Abdullah Mohammed Al-Subhi ◽  
Mohammed Ali Alsaafani
Keyword(s):  
Sea Level ◽  
West Coast ◽  
Arabian Gulf ◽  
Tide Gauges ◽  
The West ◽  
Satellite Altimeter ◽  
Mean Sea Level ◽  
Sea Level Trend
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