Absolute Comparison of Satellite Altimetry and Tide Gauge Registrations in Venezuela

The main aim of the article was to analyse the actual accuracy of determining the vertical movements of the Earth’s crust (VMEC) based on time series made of four measurement techniques: satellite altimetry (SA), tide gauges (TG), fixed GNSS stations and radar interferometry. A relatively new issue is the use of the persistent scatterer InSAR (PSInSAR) time series to determine VMEC. To compare the PSInSAR results with GNSS, an innovative procedure was developed: the workflow of determining the value of VMEC velocities in GNSS stations based on InSAR data. In our article, we have compiled 110 interferograms for ascending satellites and 111 interferograms for descending satellites along the European coast for each of the selected 27 GNSS stations, which is over 5000 interferograms. This allowed us to create time series of unprecedented time, very similar to the time resolution of time series from GNSS stations. As a result, we found that the obtained accuracies of the VMEC determined from the PSInSAR are similar to those obtained from the GNSS time series. We have shown that the VMEC around GNSS stations determined by other techniques are not the same.

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Validation of sea surface heights from satellite altimetry along the Indian coast

10.5194/egusphere-egu21-4862 ◽

2021 ◽

Author(s):

Milaa Murshan ◽

Balaji Devaraju ◽

Nagarajan Balasubramanian ◽

Onkar Dikshit

Keyword(s):

Time Series ◽

Sea Level ◽

Satellite Altimetry ◽

Tide Gauge ◽

Atmospheric Correction ◽

North Indian Ocean ◽

Sea Surface ◽

Indian Coast ◽

Vertical Land Motion ◽

And Performance

Satellite altimetry provides measurements of sea surface height of centimeter-level accuracy over open oceans. However, its accuracy reduces when approaching the coastal areas and over land regions. Despite this downside, altimetric measurements are still applied successfully in these areas through altimeter retracking processes. This study aims to calibrate and validate retracted sea level data of Envisat, ERS-2, Topex/Poseidon, Jason-1, 2, SARAL/AltiKa, Cryosat-2 altimetric missions near the Indian coastline. We assessed the reliability, quality, and performance of these missions by comparing eight tide gauge (TG) stations along the Indian coast. These are Okha, Mumbai, Karwar, and Cochin stations in the Arabian Sea, and Nagapattinam, Chennai, Visakhapatnam, and Paradip in the Bay of Bengal. To compare the satellite altimetry and TG sea level time series, both datasets are transformed to the same reference datum. Before the calculation of the bias between the altimetry and TG sea level time series, TG data are corrected for Inverted Barometer (IB) and Dynamic Atmospheric Correction (DAC). Since there are no prior VLM measurements in our study area, VLM is calculated from TG records using the same procedure as in the Technical Report NOS organization CO-OPS 065.&#160;Keywords&#8212; Tide gauge, Sea level, North Indian ocean, satellite altimetry, Vertical land motion

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Improving the Coastal Mean Dynamic Topography by Geodetic Combination of Tide Gauge and Satellite Altimetry

Marine Geodesy ◽

10.1080/01490419.2018.1530320 ◽

2018 ◽

Vol 41 (6) ◽

pp. 517-545 ◽

Cited By ~ 9

Author(s):

Ole Baltazar Andersen ◽

Karina Nielsen ◽

Per Knudsen ◽

Chris W. Hughes ◽

Rory Bingham ◽

...

Keyword(s):

Satellite Altimetry ◽

Tide Gauge ◽

Dynamic Topography ◽

Mean Dynamic Topography

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Sea level variations in the coastal region from altimetry – Using optimal interpolation in the Baltic Sea for 3-day mean sea level from altimetry, tide gauge and model data

10.5194/egusphere-egu21-10733 ◽

2021 ◽

Author(s):

Ida Margrethe Ringgaard ◽

Jacob L. Høyer ◽

Kristine S. Madsen ◽

Adili Abulaitijiang ◽

Ole B. Andersen

Keyword(s):

Baltic Sea ◽

Sea Level ◽

Temporal Resolution ◽

Satellite Altimetry ◽

Tide Gauge ◽

Coastal Region ◽

Optimal Interpolation ◽

The Baltic Sea ◽

Spatial Coverage ◽

The Baltic

The rise and fall of the sea surface in the coastal region is observed closely by two different sources: tide gauges measure the relative sea level anomaly at the coast at high temporal resolution (minutes or hours) and satellite altimeters measure the absolute sea surface height of the open ocean along tracks multiple times a day. However, these daily tracks are scattered across the Baltic Sea with each track being repeated at a lower temporal resolution (days). Due to the inverse relationship between spatial and temporal coverage of the satellite altimetry data, gridded satellite altimetry products often prioritize spatial coverage over temporal resolution, thus filtering out the high sea level variability. In other words, the satellite data, and especially averaged products, often miss the daily sea level variability, such as storm surges, which is most important for all societies in the coastal region. To compensate for the sparse spatial coverage from satellite altimetry, we here present an experimental product developed as part of the ESA project Baltic+SEAL: &#160;on a 3-day scale, the DMI Optimal Interpolation (DMI-OI) method is combined with error statistics from a storm surge model as well as 3-day averages from both tide gauge observations and satellite altimetry tracks to generate a gridded sea level anomaly product for the Baltic Sea for year 2017. The product captures the overall temporal evolution of the sea level changes well for most areas with an average RMSE wrt. tide gauge observations of 17.2 cm and a maximum of 34.2 cm. Thus, the 3-day mean gridded product shows potential as an alternative to monthly altimetry products, although further work is needed.

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Sea Level Changes Along Global Coasts from Satellite Altimetry, GPS and Tide Gauge

Satellite Positioning - Methods, Models and Applications ◽

10.5772/58972 ◽

2015 ◽

Cited By ~ 1

Author(s):

Guiping Feng ◽

Shuanggen Jin

Keyword(s):

Sea Level ◽

Satellite Altimetry ◽

Tide Gauge ◽

Sea Level Changes

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Recent Sea Level Change in the Black Sea from Satellite Altimetry and Tide Gauge Observations

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi9030185 ◽

2020 ◽

Vol 9 (3) ◽

pp. 185 ◽

Cited By ~ 1

Author(s):

Nevin Avşar ◽

Şenol Kutoğlu

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Black Sea ◽

Satellite Altimetry ◽

Tide Gauge ◽

The Black Sea ◽

Sea Level Changes ◽

Early 19Th Century ◽

Mean Sea Level ◽

The Mean

Global mean sea level has been rising at an increasing rate, especially since the early 19th century in response to ocean thermal expansion and ice sheet melting. The possible consequences of sea level rise pose a significant threat to coastal cities, inhabitants, infrastructure, wetlands, ecosystems, and beaches. Sea level changes are not geographically uniform. This study focuses on present-day sea level changes in the Black Sea using satellite altimetry and tide gauge data. The multi-mission gridded satellite altimetry data from January 1993 to May 2017 indicated a mean rate of sea level rise of 2.5 ± 0.5 mm/year over the entire Black Sea. However, when considering the dominant cycles of the Black Sea level time series, an apparent (significant) variation was seen until 2014, and the rise in the mean sea level has been estimated at about 3.2 ± 0.6 mm/year. Coastal sea level, which was assessed using the available data from 12 tide gauge stations, has generally risen (except for the Bourgas Station). For instance, from the western coast to the southern coast of the Black Sea, in Constantza, Sevastopol, Tuapse, Batumi, Trabzon, Amasra, Sile, and Igneada, the relative rise was 3.02, 1.56, 2.92, 3.52, 2.33, 3.43, 5.03, and 6.94 mm/year, respectively, for varying periods over 1922–2014. The highest and lowest rises in the mean level of the Black Sea were in Poti (7.01 mm/year) and in Varna (1.53 mm/year), respectively. Measurements from six Global Navigation Satellite System (GNSS) stations, which are very close to the tide gauges, also suggest that there were significant vertical land movements at some tide gauge locations. This study confirmed that according to the obtained average annual phase value of sea level observations, seasonal sea level variations in the Black Sea reach their maximum annual amplitude in May–June.

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Quantifying the impact of basin dynamics on the regional sea level rise in the Black Sea

Ocean Science ◽

10.5194/os-13-443-2017 ◽

2017 ◽

Vol 13 (3) ◽

pp. 443-452 ◽

Cited By ~ 5

Author(s):

Arseny A. Kubryakov ◽

Sergey V. Stanichny ◽

Denis L. Volkov

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Black Sea ◽

Satellite Altimetry ◽

Tide Gauge ◽

The Black Sea ◽

Southeastern Part ◽

Mean Sea Level ◽

The Impact ◽

Dynamic Sea Level

Abstract. Satellite altimetry measurements show that the magnitude of the Black Sea sea level trends is spatially uneven. While the basin-mean sea level rise from 1993 to 2014 was about 3.15 mm yr−1, the local rates of sea level rise varied from 1.5–2.5 mm yr−1 in the central part to 3.5–3.8 mm yr−1 at the basin periphery and over the northwestern shelf and to 5 mm yr−1 in the southeastern part of the sea. We show that the observed spatial differences in the dynamic sea level (anomaly relative to the basin-mean) are caused by changes in the large- and mesoscale dynamics of the Black Sea. First, a long-term intensification of the cyclonic wind curl over the Black Sea, observed in 1993–2014, strengthened divergence in the center of the basin and led to the rise of the sea level in coastal and shelf areas and a lowering in the basin's interior. Second, an extension of the Batumi anticyclone to the west resulted in ∼  1.2 mm yr−1 higher rates of sea level rise in the southeastern part of the sea. Further, we demonstrate that the large-scale dynamic sea level variability in the Black Sea can be successfully reconstructed using the wind curl obtained from an atmospheric reanalysis. This allows for the correction of historical tide gauge records for dynamic effects in order to derive more accurate estimates of the basin-mean sea level change in the past, prior to the satellite altimetry era.

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More confounders at global and decadal scales in detecting recent sea level accelerations

Journal of Geodetic Science ◽

10.1515/jogs-2015-0020 ◽

2015 ◽

Vol 5 (1) ◽

Author(s):

H. Bâki Iz

Keyword(s):

Sea Level ◽

Satellite Altimetry ◽

Tide Gauge ◽

Almost Periodic ◽

Altimetry Data ◽

Tide Gauge Data ◽

Gauge Data ◽

Close Range ◽

Globally Distributed ◽

Satellite Altimetry Data

AbstractThe residuals of 27 globally distributed long tide gauge recordswere scrutinized after removing the globally compounding effect of the periodic lunar node tides and almost periodic solar radiation’s sub and superharmonics from the tide gauge data. The spectral analysis of the residuals revealed additional unmodeled periodicities at decadal scales, 19 of which are within the close range of 12–14 years, at 27 tide gauge stations. The amplitudes of the periodicitieswere subsequently estimated for the spectrally detected periods and they were found to be statistically significant (p «0.05) for 18 out of 27 globally distributed tide gauge stations. It was shown that the estimated amplitudes at different localities may have biased the outcome of all the previous studies based on tide gauge or satellite altimetry data that did not account for these periodicities, within the range −0.5 – 0.5 mm/yr., acting as another confounder in detecting 21st century sea level rise.

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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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