The Sea Level of Guam

Analysis of The Sea Level Rise of Guam

10.20944/preprints201803.0196.v2 ◽

2018 ◽

Author(s):

Albert Parker ◽

Clifford D. Ollier

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Tide Gauge ◽

Tide Gauges ◽

Single Measurement ◽

Sea Level Acceleration ◽

The Stability

Many reported sea level records are often not a single measurement. They are then a composition of different records from several tide gauges. Sometimes, they are from the same tide gauge, but the tide gauge stability has been affected by earthquakes. This is the case of Guam as discussed in the present manuscript. The claimed sea level acceleration of Guam is only the result of two earthquakes that have compromised the stability of the tide gauge.

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Sinking Tide Gauge Revealed by Space-borne InSAR: Implications for Sea Level Acceleration at Pohang, South Korea

Remote Sensing ◽

10.3390/rs11030277 ◽

2019 ◽

Vol 11 (3) ◽

pp. 277 ◽

Cited By ~ 5

Author(s):

Suresh Palanisamy Vadivel ◽

Duk-jin Kim ◽

Jungkyo Jung ◽

Yang-Ki Cho ◽

Ki-Jong Han ◽

...

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Tide Gauge ◽

Tide Gauges ◽

Tide Gauge Records ◽

Relative Sea Level ◽

Tide Gauge Station ◽

Sea Level Acceleration ◽

Vertical Land Motion ◽

Gauge Station

Vertical land motion at tide gauges influences sea level rise acceleration; this must be addressed for interpreting reliable sea level projections. In recent years, tide gauge records for the Eastern coast of Korea have revealed rapid increases in sea level rise compared with the global mean. Pohang Tide Gauge Station has shown a +3.1 cm/year sea level rise since 2013. This study aims to estimate the vertical land motion that influences relative sea level rise observations at Pohang by applying a multi-track Persistent Scatter Interferometric Synthetic Aperture Radar (PS-InSAR) time-series analysis to Sentinel-1 SAR data acquired during 2015–2017. The results, which were obtained at a high spatial resolution (10 m), indicate vertical ground motion of −2.55 cm/year at the Pohang Tide Gauge Station; this was validated by data from a collocated global positioning system (GPS) station. The subtraction of InSAR-derived subsidence rates from sea level rise at the Pohang Tide Gauge Station is 6 mm/year; thus, vertical land motion significantly dominates the sea level acceleration. Natural hazards related to the sea level rise are primarily assessed by relative sea level changes obtained from tide gauges; therefore, tide gauge records should be reviewed for rapid vertical land motion along the vulnerable coastal areas.

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Testing an “IoT” Tide Gauge Network for Coastal Monitoring

IoT ◽

10.3390/iot2010002 ◽

2021 ◽

Vol 2 (1) ◽

pp. 17-32

Author(s):

Philip Knight ◽

Cai Bird ◽

Alex Sinclair ◽

Jonathan Higham ◽

Andy Plater

Keyword(s):

Sea Level ◽

Morphological Changes ◽

Tide Gauge ◽

Low Cost ◽

Pressure Sensors ◽

Wave Activity ◽

Tide Gauges ◽

Coastal Monitoring ◽

Level Data ◽

Operational Constraints

A low-cost “Internet of Things” (IoT) tide gauge network was developed to provide real-time and “delayed mode” sea-level data to support monitoring of spatial and temporal coastal morphological changes. It is based on the Arduino Sigfox MKR 1200 micro-controller platform with a Measurement Specialties pressure sensor (MS5837). Experiments at two sites colocated with established tide gauges show that these inexpensive pressure sensors can make accurate sea-level measurements. While these pressure sensors are capable of ~1 cm accuracy, as with other comparable gauges, the effect of significant wave activity can distort the overall sea-level measurements. Various off-the-shelf hardware and software configurations were tested to provide complementary data as part of a localized network and to overcome operational constraints, such as lack of suitable infrastructure for mounting the tide gauges and for exposed beach locations.

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Recent sea level rise on Ireland's east coast based on multiple tide gauge analysis

10.5194/os-2020-81 ◽

2020 ◽

Author(s):

Amin Shoari Nejad ◽

Andrew C. Parnell ◽

Alice Greene ◽

Brian P. Kelleher ◽

Gerard McCarthy

Keyword(s):

Time Series ◽

Sea Level Rise ◽

Sea Level ◽

Continuous Time ◽

East Coast ◽

Tide Gauge ◽

Tide Gauges ◽

Missing Value ◽

Global Average ◽

Good Agreement

Abstract. We analysed multiple tide gauges from the east coast of Ireland over the period 1938–2018. We validated the different time series against each other and performed a missing value imputation exercise, which enabled us to produce a homogenised record. The recordings of all tide gauges were found to be in good agreement between 2003–2015, though this was markedly less so from 2016 to the present. We estimate the sea level rise in Dublin port for this period at 10 mm yr−1. The rate over the longer period of 1938–2015 was 1.67 mm yr−1 which is in good agreement with the global average. We found that the rate of sea level rise in the longer term record is cyclic with some extreme upward and downward trends. However, starting around 1980, Dublin has seen significantly higher rates that have been always positive since 1996, and this is mirrored in the surrounding gauges. Furthermore, our analysis indicates an increase in sea level variability since 1980. Both decadal rates and continuous time rates are calculated and provided with uncertainties in this paper.

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Validation of Copernicus Sea Level Altimetry Products in the Baltic Sea and Estonian Lakes

Remote Sensing ◽

10.3390/rs12244062 ◽

2020 ◽

Vol 12 (24) ◽

pp. 4062

Author(s):

Aive Liibusk ◽

Tarmo Kall ◽

Sander Rikka ◽

Rivo Uiboupin ◽

Ülo Suursaar ◽

...

Keyword(s):

Baltic Sea ◽

Sea Level ◽

Tide Gauge ◽

Tide Gauges ◽

The Baltic Sea ◽

Geoid Model ◽

Temporal Sampling ◽

Level 3 ◽

The Baltic ◽

Level 2

Multi-mission satellite altimetry (e.g., ERS, Envisat, TOPEX/Poseidon, Jason) data have enabled a synoptic-scale view of ocean variations in past decades. Since 2016, the Sentinel-3 mission has provided better spatial and temporal sampling compared to its predecessors. The Sentinel-3 Ku/C Radar Altimeter (SRAL) is one of the synthetic aperture radar altimeters (SAR Altimeter) which is more precise for coastal and lake observations. The article studies the performance of the Sentinel-3 Level-2 sea level altimetry products in the coastal areas of the Baltic Sea and on two lakes of Estonia. The Sentinel-3 data were compared with (i) collocated Global Navigation Satellite System (GNSS) ship measurements, (ii) the Estonian geoid model (EST-GEOID2017) together with sea-level anomaly corrections from the tide gauges, and (iii) collocated buoy measurements. The comparisons were carried out along seven Sentinel-3A/B tracks across the Baltic Sea and Estonian lakes in 2019. In addition, the Copernicus Marine Environment Monitoring Service (CMEMS) Level-3 sea-level products and the Nucleus for European Modelling of the Ocean (NEMO) reanalysis outcomes were compared with measurements from Estonia’s 21 tide gauges and the buoy deployed offshore. Our results showed that the uncertainty of the Sentinel-3 Level-2 altimetry product was below decimetre level for the seacoast and the selected lakes of Estonia. Results from CMEMS Level-3 altimetry products showed a correlation of 0.83 (RMSE 0.18 m) and 0.91 (RMSE 0.27 m) when compared against the tide gauge measurements and the NEMO model, respectively. The overall performance of the altimetry products was very good, except in the immediate vicinity of the coastline and for the lakes, where the accuracy was nearly three times lower than for the open sea, but still acceptably good.

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Sea level trend and variability around Peninsular Malaysia

Ocean Science ◽

10.5194/os-11-617-2015 ◽

2015 ◽

Vol 11 (4) ◽

pp. 617-628 ◽

Cited By ~ 18

Author(s):

Q. H. Luu ◽

P. Tkalich ◽

T. W. Tay

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Satellite Altimetry ◽

Tide Gauge ◽

Peninsular Malaysia ◽

Tide Gauges ◽

Tide Gauge Records ◽

Regional Sea Level ◽

Malacca Strait ◽

Singapore Strait

Abstract. Sea level rise due to climate change is non-uniform globally, necessitating regional estimates. Peninsular Malaysia is located in the middle of Southeast Asia, bounded from the west by the Malacca Strait, from the east by the South China Sea (SCS), and from the south by the Singapore Strait. The sea level along the peninsula may be influenced by various regional phenomena native to the adjacent parts of the Indian and Pacific oceans. To examine the variability and trend of sea level around the peninsula, tide gauge records and satellite altimetry are analyzed taking into account vertical land movements (VLMs). At annual scale, sea level anomalies (SLAs) around Peninsular Malaysia on the order of 5–25 cm are mainly monsoon driven. Sea levels at eastern and western coasts respond differently to the Asian monsoon: two peaks per year in the Malacca Strait due to South Asian–Indian monsoon; an annual cycle in the remaining region mostly due to the East Asian–western Pacific monsoon. At interannual scale, regional sea level variability in the range of ±6 cm is correlated with El Niño–Southern Oscillation (ENSO). SLAs in the Malacca Strait side are further correlated with the Indian Ocean Dipole (IOD) in the range of ±5 cm. Interannual regional sea level falls are associated with El Niño events and positive phases of IOD, whilst rises are correlated with La Niña episodes and negative values of the IOD index. At seasonal to interannual scales, we observe the separation of the sea level patterns in the Singapore Strait, between the Raffles Lighthouse and Tanjong Pagar tide stations, likely caused by a dynamic constriction in the narrowest part. During the observation period 1986–2013, average relative rates of sea level rise derived from tide gauges in Malacca Strait and along the east coast of the peninsula are 3.6±1.6 and 3.7±1.1 mm yr−1, respectively. Correcting for respective VLMs (0.8±2.6 and 0.9±2.2 mm yr−1), their corresponding geocentric sea level rise rates are estimated at 4.4±3.1 and 4.6±2.5 mm yr−1. The geocentric rates are about 25 % faster than those measured at tide gauges around the peninsula; however, the level of uncertainty associated with VLM data is relatively high. For the common period between 1993 and 2009, geocentric sea level rise values along the Malaysian coast are similar from tide gauge records and satellite altimetry (3.1 and 2.7 mm yr−1, respectively), and arguably correspond to the global trend.

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Using continuous GPS and absolute gravity to separate vertical land movements and changes in sea-level at tide-gauges in the UK

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2006.1746 ◽

2006 ◽

Vol 364 (1841) ◽

pp. 917-930 ◽

Cited By ~ 45

Author(s):

F.N Teferle ◽

R.M Bingley ◽

S.D.P Williams ◽

T.F Baker ◽

A.H Dodson

Keyword(s):

Time Series ◽

Sea Level ◽

Tide Gauge ◽

Absolute Gravity ◽

Tide Gauges ◽

Tide Gauge Record ◽

Vertical Movements ◽

Movement Component ◽

The Uk ◽

Continuous Gps

Researchers investigating climate change have used historical tide-gauge measurements from all over the world to investigate the changes in sea-level that have occurred over the last century or so. However, such estimates are a combination of any true sea-level variations and any vertical movements of the land at the specific tide-gauge. For a tide- gauge record to be used to determine the climate related component of changes in sea-level, it is therefore necessary to correct for the vertical land movement component of the observed change in sea-level. In 1990, the Institute of Engineering Surveying and Space Geodesy and Proudman Oceanographic Laboratory started developing techniques based on the Global Positioning System (GPS) for measuring vertical land movements (VLM) at tide-gauges in the UK. This paper provides brief details of these early developments and shows how they led to the establishment of continuous GPS (CGPS) stations at a number of tide-gauges. The paper then goes on to discuss the use of absolute gravity (AG), as an independent technique for measuring VLM at tide-gauges. The most recent results, from CGPS time-series dating back to 1997 and AG time-series dating back to 1995/1996, are then used to demonstrate the complementarity of these two techniques and their potential for providing site-specific estimates of VLM at tide-gauges in the UK.

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Review and Assessment of gap-filling methods from tide-gauges: Maxima missing at the Esbjerg, Denmark station, before 1910.

10.5194/egusphere-egu2020-4487 ◽

2020 ◽

Author(s):

Peter Thejll

Keyword(s):

Sea Level ◽

Tide Gauge ◽

Model Fit ◽

Tide Gauges ◽

Harmonic Model ◽

Gap Filling ◽

Tide Gauge Data ◽

Tide Gauge Record ◽

Long Baseline ◽

Gauge Data

Information on extremes of the sea-level is obtained from tide-gauge records. &#160;Such records may have gaps.Estimates of potential changes in the size and/or frequency of sea-level extremes are hampered by long gaps, or when just the high extremes are missing due, e.g. to equipment failure.Methods used for filling such gaps can be based on having multiple records from gauges near each other; but what to do if there is only one record? This problem can typically occur when old tide-gauge records are used -- the use of multiple recorders at the same place is more wide-spread today. However, especially older and therefore longer records hold the key to obtaining long-baseline insights into the temporal evolution of extreme tides and thus impacts of e.g. climate change.In this work, we review and assess methods for gap filling. We asses using the 'known truth' method, i.e. by applying realistic gaps to complete gauge records and reconstructing and then comparing errors calculated as the diffrence between modelled and actual values. &#160;We compare a simple harmonic model fit method to various spline methods as well as Neural network and deep learning approches. &#160;We also test a hybrid method which uses not just tide-gauge data but also air pressure readings from a meteorological station near the tide-gauge.We then attempt to fill in the missing maxima of the Esbjerg, Denmark hourly tide-gauge record since 1889. Particularly, before 1910 the maxima above 300 cm are missing (Bijl, et al., 1999), and we try to fill these in.

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Comparing satellite altimetry and tide gauges observations in the Mediterranean Sea within the framework of singular spectrum analysis

MAUSAM ◽

10.54302/mausam.v71i2.18 ◽

2021 ◽

Vol 71 (2) ◽

pp. 187-198

Author(s):

HADDAD MAHDI ◽

TAIBI HEBIB ◽

MOKRANE MOUSTAFA ◽

HAMMOUMI HOUSSEYN

Keyword(s):

Sea Level ◽

Spectrum Analysis ◽

Satellite Altimetry ◽

Tide Gauge ◽

Singular Spectrum Analysis ◽

Altimetry Data ◽

Tide Gauges ◽

The Mediterranean ◽

Satellite Altimetry Data

By considering time series from satellite altimetry and tide gauges that extend back to 1993, Singular Spectrum Analysis (SSA) is applied to investigate and compare the non linear trends of the sea level along the Mediterranean coasts. The major issue of this comparison is to show if the satellite altimetry data could be representative of the local sea level as observed by tide gauges. The results indicate that the local trends estimated from an in-situ tide gauge and satellite altimetry data show nearly identical positive rates over the period from 1993 to 2017. The differences between the estimated rates of sea level change from in-situ tide gauge and satellite measurements vary, in absolute value, from 0.18 to 4.29 mm/year with an average of 1.55 mm/year. This result is sufficient to admit, if necessary, on the one hand, the complementarily of the two measurement techniques (satellite altimetry and tide gauges) and, on the other hand, the rise in sea level near the Mediterranean coastal areas.

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Tide Gauge Records May Underestimate 20th Century Sea Level Rise

Eos ◽

10.1029/2016eo059979 ◽

2016 ◽

Vol 97 ◽

Author(s):

Leah Crane

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

20Th Century ◽

Tide Gauge ◽

Sea Level Change ◽

Tide Gauges ◽

Tide Gauge Records ◽

Level Change

Tide gauges can help measure sea level change, but their limited locations and short records make it hard to pinpoint trends. Now researchers are evaluating the instruments' limitations.

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