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

2020 ◽  
Vol 9 (3) ◽  
pp. 185 ◽  
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.

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

Ocean Science ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 443-452 ◽  
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.

scholarly journals INVESTIGATON OF SEA LEVEL CHANGE ALONG THE BLACK SEA COAST FROM TIDE GAUGE AND SATELLITE ALTIMETRY

2015 ◽  
Vol XL-1-W5 ◽  
pp. 67-71 ◽  
Author(s):  
N. B. Avsar ◽  
S. H. Kutoglu ◽  
S. Jin ◽  
B. Erol
Keyword(s):  
Sea Level ◽  
Black Sea ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
The Black Sea ◽  
Level Change ◽  
Black Sea Coast ◽  
Grid Points ◽  
Sea Coast

In this study, we focus on sea level changes along the Black Sea coast. For this purpose, at same observation period the linear trends and the components of seasonal variations of sea level change are estimated at 12 tide gauge sites (Amasra, Igneada, Trabzon-II, Sinop, Sile, Poti, Batumi, Sevastopol, Tuapse, Varna, Bourgas, and Constantza) located along the Black Sea coast and available altimetric grid points closest to the tide gauge locations. The consistency of the results derived from both observations are investigated and interpreted. Furthermore, in order to compare the trends at the same location, it is interpolated from the trends obtained at the altimetric grid points in the defined neighbouring area with a diameter of 0.125° using a weighted average interpolation algorithm at each tide gauge site. For some tide gauges such as Sevastopol, Varna, and Bourgas, it is very likely that the trend estimates are not reliable because the time-spans overlapping the altimeter period are too short. At Sile, the long-term change for the time series of both data types do not give statistically significant linear rates. However, when the sites have long-term records, a general agreement between the satellite altimetry and tide gauge time series is observed at Poti (~20 years) and Tuapse (~18 years). On the other hand, the difference of annual phase between satellite altimetry and tide gauge results is from 1.32° to 71.48°.

scholarly journals KENAIKAN MUKA AIR LAUT PERAIRAN SUMATERA BARAT BERDASARKAN DATA SATELIT ALTIMETRI JASON-2

GEOMATIKA ◽  
2017 ◽  
Vol 23 (1) ◽  
pp. 1
Author(s):  
Isna Uswatun Khasanah
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Linear Regression Analysis ◽  
Coastal Areas ◽  
Sea Level Anomaly ◽  
Mean Sea Level ◽  
Development Plans ◽  
The Mean

<p><em>The phenomenon of the sea level rise caused by many factors, one of which is global warming. Coastal areas are most vulnerable regions affected by sea level rise. Therefore, the information of sea level rise are used as consideration and policy-making on development plans for coastal areas like in West Sumatera Waters. The aims of this research are to identify the quality of Satelit Altimetry Jason-2 Data in West Sumatera Waters and to analysis the information of sea level rise of West Sumatera sea based on satelit altimetry Jason-2 data. Sea Level Rise in West Sumatera Water are identified by several steps, begin with collecting satellite altimetry Jason-2 data from 2008 to 2015 years. Then extraction Sea Surface Height (SSH) value of  binary GDR data from Jason-2 by post processing to eliminate the geophysic errors, furthermore extraction undulation geoid value and calculating the Sea Level Anomaly (SLA) value. To identify the sea level rise value used linear regression analysis on the SLA data.  The results of this research shown the existence of satellite altimetry Jason-2 data is 92.91%. The mean sea level rise in West Sumatera Waters during th period 8 year is 6.88 mm, and mean sea level rise of West Sumatera sea is 0.86 mm/year.</em></p>

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

2019 ◽  
Vol 7 (3) ◽  
pp. 61 ◽  
Author(s):  
Carlos Antunes
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
21St Century ◽  
West Coast ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Relative Sea Level ◽  
Mean Sea Level ◽  
Relative Sea Level Rise ◽  
Global Sea Level

Based on the updated relative sea level rise rates, 21st-century projections are made for the west coast of Portugal Mainland. The mean sea level from Cascais tide gauge and North Atlantic satellite altimetry data have been analyzed. Through bootstrapping linear regression and polynomial adjustments, mean sea level time series were used to calculate different empirical projections for sea level rise, by estimating the initial velocity and its corresponding acceleration. The results are consistent with 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. Applying 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 vertical land velocity and residual synoptic regional dynamic effects. 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. A mean sea level rise of 1.14 m was obtained for the epoch of 2100, with a likely range of 95% of probability between 0.39 m and 1.89 m.

scholarly journals Effects of the basin dynamics on sea level rise in the Black Sea

2016 ◽  
Author(s):  
A. A. Kubryakov ◽  
S. V. Stanichny ◽  
D. L. Volkov
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Black Sea ◽  
Tide Gauge ◽  
The Black Sea ◽  
Tide Gauges ◽  
Tide Gauge Records ◽  
Sea Levels ◽  
The Difference

Abstract. Satellite altimetry measurements show that magnitude of the Black Sea level trends is spatially uneven. While the basin-averaged sea level was increasing at a rate of 3.15 mm/year from 1993 to 2014, the sea level rise varied from 0.15–2.5 mm/year in the central part to 3.5–3.8 mm/year in coastal areas and 5 mm/year in the southwestern part of the sea. These differences are caused by changes in the large- and mesoscale circulation of the Black Sea. A long-term increase of the cyclonic wind curl over the basin from 1979 to 2014 strengthened divergence in the center of the Black Sea that led to an increase of sea level near the coast and a decrease in the center of the basin. Changes in the distribution and intensity of mesoscale eddies caused the formation of the local extremes of sea level trend. The variability of the dynamic sea level (DSL) – the difference between the local and the basin-averaged sea levels – contributes significantly (up to ~ 50 % of the total variance) to the seasonal and interannual variability of sea level in the basin. The DSL variability in the Black Sea depends strongly on the basin-averaged wind curl and is well reconstructed using the ERA-Interim winds from 1979 to present, including the time when altimetry data was unavailable. The reconstruction can be used to correct historical tide gauges data for dynamic effects, which are usually neglected in the analysis of the Black Sea tide gauge records.

scholarly journals RELATIVE SEA LEVEL CHANGE ALONG THE BLACK SEA COAST FROM TIDE-GAUGE OBSERVATIONS

2019 ◽  
Vol XLII-3/W8 ◽  
pp. 43-47 ◽  
Author(s):  
N. B. Avsar ◽  
S. H. Kutoglu
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Black Sea ◽  
Tide Gauge ◽  
Sea Level Change ◽  
The Black Sea ◽  
Relative Sea Level ◽  
Level Change ◽  
Black Sea Coast ◽  
Gauge Station

<p><strong>Abstract.</strong> Potential sea level rise poses a significant threat to low-lying areas. Considering present and future of coastal areas, scientific study of sea level rise is an essential for adapting to sea level extremes. In this study, the relative sea level change in the Black Sea were investigated using data of 12 tide-gauge and 6 GNSS stations. Results generally indicated sea level rise along the Black Sea coast. Only at Bourgas tide-gauge station, a sea level fall was detected. A significant sea level change were not determined at Sinop tide-gauge station. On the other hand, at some stations such as Poti and Sile, ground subsidence contribution to relative sea level changes were observed.</p>

The sources of sea-level rise in the Mediterranean Sea since 1960

2021 ◽  
Author(s):  
Francisco Mir Calafat ◽  
Thomas Frederikse ◽  
Kevin Horsburgh ◽  
Nadim Dayoub
Keyword(s):  
Sea Level Rise ◽  
Mediterranean Sea ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Sea Level Changes ◽  
Tide Gauge Records ◽  
Land Mass ◽  
The Mediterranean ◽  
Dynamic Sea Level

&lt;p&gt;Sea-level change is geographically non-uniform, with regional departures that can reach several times the global average. Characterizing this spatial variability and understanding its causes is crucial to the design of adaptation strategies for sea-level rise. This, as it turns out, is no easy feat, primarily due to the sparseness of the observational sea-level record in time and space. Long tide gauge records are restricted to a few locations along the coast. Satellite altimetry offers a better spatial coverage but only since 1992. In the Mediterranean Sea, the tide gauge network is heavily biased towards the European shorelines, with only one record with at least 35 years of data on the African coasts. Past studies have attempted to address the difficulties related to this data sparseness in the Mediterranean Sea by combining the available tide gauge records with satellite altimetry observations. The vast majority of such studies represent sea level through a combination of altimetry-derived empirical orthogonal functions whose temporal amplitudes are then inferred from the tide gauge data. Such methods, however, have tremendous difficulty in separating trends and variability, make no distinction between relative and geocentric sea level, and tell us nothing about the causes of sea level changes. Here, we combine observational data from tide gauges and altimetry with sea-level fingerprints of land-mass changes through a Bayesian hierarchical model to quanify the sources of sea-level rise since 1960 at any arbitrary location in the Mediterranean Sea. We find that Mediterranean sea level rose at a relatively low rate from 1960 to 1990, primarily due to dynamic sea-level changes in the nearby Atlantic, at which point it started rising significantly faster with comparable contributions from dynamic sea level and land-mass changes.&lt;/p&gt;

scholarly journals A new assessment of the error budget of global mean sea level rate estimated by satellite altimetry over 1993–2008

Ocean Science ◽  
2009 ◽  
Vol 5 (2) ◽  
pp. 193-201 ◽  
Author(s):  
M. Ablain ◽  
A. Cazenave ◽  
G. Valladeau ◽  
S. Guinehut
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
Mean Sea Level ◽  
Error Budget ◽  
Isostatic Adjustment ◽  
Tide Gauge Measurements ◽  
Global Mean Sea Level ◽  
Global Mean

Abstract. A new error budget assessment of the global Mean Sea Level (MSL) determined by TOPEX/Poseidon and Jason-1 altimeter satellites between January 1993 and June 2008 is presented using last altimeter standards. We discuss all potential errors affecting the calculation of the global MSL rate. We also compare altimetry-based sea level with tide gauge measurements over the altimetric period. Applying a statistical approach, this allows us to provide a realistic error budget of the MSL rise measured by satellite altimetry. These new calculations highlight a reduction in the rate of sea level rise since 2005, by ~2 mm/yr. This represents a 60% reduction compared to the 3.3 mm/yr sea level rise (glacial isostatic adjustment correction applied) measured between 1993 and 2005. Since November 2005, MSL is accurately measured by a single satellite, Jason-1. However the error analysis performed here indicates that the recent reduction in MSL rate is real.

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