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EN
Santos’s mangroves are important wetlands located in Brazilian coast, a fishing area inside Santos Bay. The overall healthy mangroves area along the riparian zones influencing the Santos Estuary is around 25.20 km2. The resulting tidal level recorded from Port of Santos tide gauge (from 1940 to 2014), also located in the estuary, shows consistent increasing trend. One healthy mangrove was selected for a previous qualitative biological survey to better understand the characteristics of the habitat to be monitored and evaluated about the possible impacts in the next decades. The mangroves situated a few meters upper from the sea level and some other areas have the risk to be submerged till 2085 which will seriously affect the riparian mangroves biome. Indeed, the mangrove area is confined downward by the low tide level and upward by existing structures, roads, rural and urban areas.
EN
The process of global sea level rise is causing several significant changes in the coastal zone. Sea level rise and the frequency, strength and duration of storms are also occurring on the Polish coast. As a result, coastal protection measures, such as man-made engineering structure, are necessary. These engineering structures affect (among others) the marine ecosystem in different ways. Although the presence of such engineering structures can cause changes in the bathymetry of waterbody and the transport of sediments along the basin, it also slows down the erosion of the shoreline. For this reason, comprehensive knowledge of natural conditions, including dynamic and variable factors, is essential in the construction of a hydro-engineering structures. The correct determination of the environmental conditions helps to minimize environmental damage. Prior to interventions on the coast, the issues addressed in the paper should be analysed and studied. In this paper, the influence of shoreline structures on the main factors responsible for the development of tombolo phenomenon is discussed. In addition, the lithological diversity of surface sediments on which the rate of coastal erosion depends, is also discussed. An important element of the work is the descriptions of tombolo in Poland. They contain information on the causes of the phenomenon, as well as about the negative consequences of a disturbance of the hydrodynamic dynamics caused by the structure.
EN
The Gulf of Maranhão, North Coast of Brazil, is one of the regions in the world with largest tidal ranges. The Port Area of Maranhão, in São Marcos Bay, represents the second most important in Brazil. The port facilities are naturally sheltered from swell, with nautical operations and maintenance dredging volumes directly conditioned by macro-tides, which exceed the 6.0 m tidal range, and associated tidal currents, which can reach 7.0 knots. In order to assess the behavior of sea levels in recent decades, in view of the influence of climate changes on tides in various ports around the world, a period of two lunar nodal tidal cycles of 18.61 years, from 1980 to 2017, was investigated using unpublished data recorded in tide gauges. The trend pattern obtained was analyzed statistically and, unlike many other port areas, a sensitive stability of the mean sea level was noted. An important conclusion is about the reduction in HHW and increasing in LLW, leading to a reduction in tidal ranges, in tidal currents and a significant reduction of the shear stress in the bottom, which may increase the dredging rates in the port areas in the next decades, due to an increasing siltation.
EN
Tide gauge observations provide sea level relative to the Earth’s crust, while satellite altimetry measures sea level variations relative to the centre of the Earth’s mass. Local vertical land motion can be a significant contribution to the measured sea level change. Satellite altimetry was traditionally used to study the open ocean, but this technology is now being used over inland seas too. The difference of both observations can be used to estimate vertical crustal movement velocities along the sea coast. In this paper, vertical crustal movement velocities were investigated at tide gauge sites along the Adriatic Sea coast by analyzing differences between Tide Gauge (TG) and Satellite Altimetry (SA) observations. Furthermore, the estimated vertical motion rates were compared with those from nearby GNSS measurements. The study determines the practical relationships between these vertical crustal movements and those determined from unrelated data acquired from the neighbouring GNSS stations. The results show general consistence with the present geodynamics in the Adriatic Sea coastal zone.
EN
This work examines the multiscale variability in sea level along the English Channel coasts (NW France) using a wavelet multiresolution decomposition of water level values and climate oscillations in order to gain insights in the connection between the global atmospheric circulation and the local-scale variability of the monthly extreme surges. Changes in surges have exhibited different oscillatory components from the intermonthly (~3-6-months) to the interannual scales (~1.5-years, ~2-4-years, ~5-8-years) with mean explained variances of ~40% and ~25% of the total variability respectively. The correlation between the multiresolution components of surges and 28 exceptional stormy events with different intensities has revealed that energetic events are manifested at all timescales while moderate events are limited to short scales. By considering the two hypotheses of (1) the physical mechanisms of the atmospheric circulation change according to the timescales and (2) their connection with the local variability improves the prediction of the extremes, the multiscale components of the monthly extreme surges have been investigated using four different climate oscillations (Sea Surface Temperature (SST), Sea-Level Pressure (SLP), Zonal Wind (ZW), and North Atlantic Oscillation (NAO)); results show statistically significant correlations with ~3-6-months, ~1.5-years, ~2-4-years, and ~5-8-years, respectively. Such physical links, from global to local scales, have been considered to model the multiscale monthly extreme surges using a time-dependent Generalized Extreme Value (GEV) distribution. The incorporation of the climate information in the GEV parameters has considerably improved the fitting of the different timescales of surges with an explained variance higher than 30%. This improvement exhibits their nonlinear relationship with the large-scale atmospheric circulation.
EN
Climate change is expected to adversely afect the coastal ecosystem in many ways. One of the major consequences of climate change in coastal areas is sea level rise. In order to manage this problem efciently, it is essential to obtain reasonably accurate estimates of future sea level. This study focuses essentially on the identifcation of climatic variables infuencing sea level and sea level prediction. Correlation analysis and wavelet coherence diagrams were used for identifying the infuencing variables, and support vector machine (SVM) and hybrid wavelet support vector machine (WSVM) techniques were used for sea level prediction. Sea surface temperature, sea surface salinity, and mean sea level pressure were observed to be the major local climatic variables infuencing sea level. Halosteric efect is found to have a major impact on the sea level. The variables identifed were subsequently used as predictors in both SVM and WSVM. WSVM employs discrete wavelet transform to decompose the variables before being input to the SVM model. The performance of both the models was compared using statistical measures such as root mean square error (RMSE), correlation coefcient (r), coefcient of determination (r 2 ), average squared error, Nash–Sutclife efciency, and percentage bias along with graphical indicators such as Taylor diagrams and regression error characteristic curves. Results indicate that the WSVM model predicted sea level with an RMSE of 0.029 m during the training and 0.040 m during the testing phases. The corresponding values for SVM are 0.043 m and 0.069 m, respectively. Also, the other statistical measures and graphical indicators suggest that WSVM technique outperforms the SVM approach in the prediction of sea level.
EN
In the context of the environmental monitoring of the Concordia wreck removal project, measurements of currents, winds and sea level height were made along the eastern coast of the Giglio Island, Tyrrhenian Sea (Italy), during 2012–2013. The aim of the study was to investigate the effect of atmospheric forcing and periodic sea-level changes on the coastal currents. Normalised Cross-Correlation Function analysis allowed us to correlate these observations. A marked inter-seasonal variability was found in both current and local wind velocity observations but a significant level of correlation between the data was only found during strong wind events. Current and wind directions appeared to be uncorrelated and current measurements showed a predominant NW–SE direction, presumably linked to the shape and orientation of Giglio Island itself. During strong winds from the SSE, current flow was towards the NNW but it suddenly switched from the NNW to the SE at the end of wind events. The results show that, at Giglio Island, currents are principally dominated by the general cyclonic Tyrrhenian circulation, and, secondly, by strong wind events. The sea level had no effects on the current regime.
8
Content available Current state of art of satellite altimetry
EN
One of the fundamental problems of modern geodesy is precise defi nition of the gravitational fi eld and its changes in time. This is essential in positioning and navigation, geophysics, geodynamics, oceanography and other sciences related to the climate and Earth’s environment. One of the major sources of gravity data is satellite altimetry that provides gravity data with almost 75% surface of the Earth. Satellite altimetry also provides data to study local, regional and global geophysical processes, the geoid model in the areas of oceans and seas. This technique can be successfully used to study the ocean mean dynamic topography. The results of the investigations and possible products of altimetry will provide a good material for the GGOS (Global Geodetic Observing System) and institutions of IAS (International Altimetry Service). This paper presents the achievements in satellite altimetry in all the above disciplines obtained in the last years. First very shorly basic concept of satellite altimetry is given. In order to obtain the highest accuracy on range measurements over the ocean improved of altimetry waveforms performed on the ground is described. Next, signifi cant improvements of sea and ocean gravity anomalies models developed presently is shown. Study of sea level and its extremes examined, around European and Australian coasts using tide gauges data and satellite altimetry measurements were described. Then investigations of the phenomenon of the ocean tides, calibration of altimeters, studies of rivers and ice-sheets in the last years are given.
9
Content available Current State of Art of Satellite Altimetry
EN
One of the fundamental problems of modern geodesy is precise definition of the gravitational field and its changes in time. This is essential in positioning and navigation, geophysics, geodynamics, oceanography and other sciences related to the climate and Earth’s environment. One of the major sources of gravity data is satellite altimetry that provides gravity data with almost 75% surface of the Earth. Satellite altimetry also provides data to study local, regional and global geophysical processes, the geoid model in the areas of oceans and seas. This technique can be successfully used to study the ocean mean dynamic topography. The results of the investigations and possible products of altimetry will provide a good material for the GGOS (Global Geodetic Observing System) and institutions of IAS (International Altimetry Service). This paper presents the achievements in satellite altimetry in all the above disciplines obtained in the last years.
PL
Jednym z podstawowych problemów współczesnej geodezji jest dokładne określenie pola grawitacyjnego i jego zmian w czasie. Ma to zasadnicze znaczenie dla zastosowań w pozycjonowaniu i nawigacji, w geofizyce, geodynamice, oceanografii i innych naukach związanych z klimatem i środowiskiem Ziemi. Jednym z głównych źródeł danych grawimetrycznych jest altimetria satelitarna, która dostarcza dane grawimetryczne z prawie 75% powierzchni globu ziemskiego. Altimetria satelitarna dostarcza również dane do badania lokalnych, regionalnych i globalnych procesów geofizycznych, modelu geoidy na obszarach mórz i oceanów oraz średniej dynamicznej topografii oceanów. Wyniki badań i potencjalne produkty danych altimetrycznych mają stanowić materiał dla Globalnego Geodezyjnego Systemu Obserwacji GGOS (Global Geodetic Observing System) i instytucji IAS (International Altimetry Service).
EN
Neptunian sills at Rocca Busambra, a fragment of the Trapanese/Saccense Domain in western Sicily, host the most abundant ammonite and gastropod fauna which has ever been recorded from the Jurassic of the western Tethys. The fauna is dominated by parautochthonous organisms which were swept into the sills by gentle transport. Ammonites are characterized by perfect preservation and small size, a feature which is due to the predominance of microconchs but also of stunting. The most complete sill is 0.7 m thick and could be separated into 17 levels which range in age from the early Toarcian into the late Kimmeridgian, thus representing the most extreme case of palaeontologically and depositionally documented stratigraphic condensation in Earth history. The unique feature of the Rocca Busambra sills is due to the interaction of three processes: extreme stratigraphic condensation on the sea floor, weak tectonic fracturing of the host rock and repeated reopening on top of already existing sills. Contrasting percentages of gastropods in individual levels reflect sea-level oscillations which correspond to long known low- and highstands during the Jurassic of the western Tethys. Comparisons with other ammonite-bearing sill faunas reveal several similarities, but represent only short-timed phases of tectonic pulses and deposition.
11
Content available remote Baltic Sea datums and their unification as a basis for coastal and seabed studies
EN
This paper presents examples of application of a common reference datum, such as NAP, within the elevation EVRS reference system for the Baltic Sea. A common reference datum allowed for setting the geographical pattern of occurrence of extreme sea levels in the Baltic Sea. The eastern Baltic coasts exposed to western air masses are vulnerable to extreme hydrological events (the Gulf of Finland, the Gulf of Riga and the Gulf of Bothnia). On the contrary, the Swedish coasts of the central and northern Baltic are the least threatened by extreme sea levels. The south-western coasts of the Baltic Sea (the Bay of Mecklenburg and the Bay of Kiel) cover the basins with the most frequent and the most severe storm falls and extremely low sea levels. Demonstration of the Baltic surface deformation magnitude during a storm event is another example of NAP application. The instantaneous height difference between the north-eastern and southwestern coasts was 356 cm, which resulted from the negative impact of pressure (water cushion) induced by a dynamic and deep low-pressure system moving through the Baltic Sea. The common reference datum allowed for visualization of the so-called 'theoretical water' distribution which has a wide application in the hydraulic engineering within the coastal zone. In addition, the study provides examples of differences that may be observed during storm events between the real sea-level data and the hydrodynamic model forecast. This is of great practical significance in terms of forecasting storm surges in the Baltic Sea.
EN
Future sea-level changes along the Mediterranean Egyptian coast (southern Levantine sub-basin) are projected using satellite altimetry data and model simulations. Twenty-one years (1993–2013) of satellite altimetry data, represented by dynamic topography (DT), are examined in light of tide-gauge observations. Current DT changes are examined with respect to five atmospheric/oceanic factors. The qualities of three realizations of the Geophysical Fluid Dynamics Laboratory (GFDL) model are examined by comparing these with DT. Finally, the simulations best describing the present DT are used to describe projected sea-level changes in the study area. The results indicate that DT can be used to study coastal and deep-water sea-level changes in the study area. The southern Levantine sub-basin sea level has recently risen by an average of 3.1 cm decade-1 and exhibits significant annual sea-level variation of −17 cm to 8 cm. The sea-level variation is significantly affected by several factors: sea-level variation west of the Gibraltar Strait, steric sea level, and sea-surface temperature. The GFDL simulations best describing the recent sea level over the study area, i.e., GFDL-CM3 and GFDL-ESM2M, are used to calculate the two-model ensemble mean (GFDL-2ENM), which indicates that Egypt's Mediterranean coast will experience substantial sea-level rise (SLR) this century. The estimated uncertainty over the study area was 4–22 cm by 2100, with the emission assumptions dominating the three sources of uncertainty sources. Comparing the projected SLRs with digital elevation data indicates that Egypt's Mediterranean coast will only be safe from flooding by 2100 if effective adaptation methods are applied.
13
Content available remote Seasonal variability in the Baltic Sea level
EN
Sea level is subject to spatial and temporal variability on different scales. In this paper we investigate seasonal variability in the open Baltic Sea level using daily satellite altimetry data for the period 1 January 1993-31 December 2010. Our results indicate that there is a well-pronounced seasonal cycle in the 18-year average sea level and in its standard deviation. The average annual SLA amplitude in the open Baltic Sea is about 18 cm. The seasonal cycle of the SLA in the Baltic Sea is asymmetric in shape. In the autumn and winter (about 240-260 days per year), the 18-year average daily SLA are higher than the 18-year annual average SLA. In the spring and summer (about 100-120 days per year), the 18-year average daily SLA are lower than the 18-year annual average SLA. A similar asymmetry of the seasonal cycle is not observed in the North Sea and North Atlantic SLA data. The annual pattern of the sea level variability in the Baltic Sea is evident if one considers multi-year average time series, but the cycle can be obscured in some years.
14
Content available remote Recent multiyear trends in the Baltic Sea level
EN
Sea level rise is one of the most direct consequences of climate change. It has been documented that sea level rise is globally subject to considerable spatial heterogeneity. There is an increased awareness of the need to create regional data records and projections of sea level trends, because specific regional processes can cause regional trends to diverge significantly from global averages. In this paper available multimission satellite altimetry data were used to estimate the multiyear trend in the Baltic Sea level. The estimated trend is about 0.33 cm yr-1, similar to the globally averaged sea level trend, but significantly larger than the regional trends estimated in the North Sea and North Atlantic. The decadal scale variability in the sea level trend in the Baltic Sea does not indicate a significant acceleration of the trend in recent years. Our analysis confirms that the interannual variability of sea level in the Baltic in winter is significantly correlated with the North Atlantic Oscillation index.
EN
The analysis of sea level record series along the Polish coast is presented. The main aim was to identify linear trends in the sea level changes at the coastal (Świnoujście, Kołobrzeg, Ustka, Łeba, Władysławowo, Hel, Gdynia, Gdańsk), lagoonal (Trzebież, Tokmicko) and riverine (Szczecin) gauge stations. The analysis showed individual coastal stations to differ in the rate of sea level changes. During 60 years of continuous observations (1947-2006), the differences varied from 1.0 (the western part of the coast) to 2.5 mm year-1 (the eastern part of the coast). The longest, more than 100-yr-long data series showed the sea level rise in Świnoujście and Kołobrzeg to be about 0.5 mm year-1; 1.57 mm year-1 being revealed in Gdańsk. Spectral analysis applied to the data showed numerous fluctuations and cyclicity in changes of the annual mean sea level at the Polish coast. A distinct, major 3-year cycle was revealed. In addition, three secondary cycles of 4.6, 6.7, and 8.6 years were present in the data, more or less clearly identifiable at individual stations.
EN
Lagoon gyttja layers occurring in anomalously high position (up to 2.5 m above the present-day sea level) The transition phase between the Ancylus and Littorina stages of the Baltic Sea is an old controversial topic. With the newest data available we try to reach a compromise between the "dramatic" model, including a sudden and large drainage of the Ancylus Lake, and the idea of a non-existing Ancylus drainage through Denmark. This new model includes a minor, perhaps 5 m, sudden erosion and forced regression slightly before 10,000 cal. yrs BP. This was followed by a 200–300 yr long period when the outlet through Denmark and Great Belt (Dana River) was characterized by a variable fluvial environment creating fluvial, levée and lacustrine deposits. During this period of rapidly rising sea level, we postulate that the gradient between the Ancylus Lake and sea level gradually decreased from some 5 m until sea level had reached the Ancylus and Darss Sill level. After this point in time occasional pulses of marine water could easier enter into the Baltic basin, which is seen as brackish pulses as early as 9800 cal. yrs BP in records from the Bornholm and Gotland basins, but also from Blekinge. It would, however, take another c. 1500 years before the Öresund threshold was flooded by the rising sea level, causing a significant rise in salinity sometime between 8500–8000 cal. yrs BP, and marking the true onset of the Littorina Sea.
EN
The main findings of studies of the physical oceanography of the Gulf of Finland (GoF) during 1997-2007 are reviewed. The aim is to discuss relevant updates published in international peer-reviewed research papers and monographs, bearing in mind that a comprehensive overview of the studies up to the mid-1990s is available (Alenius et al. 1998). We start the discussion with updates on the basic hydrographical and stratification conditions, and progress in the understanding of atmospheric forcing and air-sea interaction. Advances in the knowledge of basin-scale and mesoscale dynamics are summarised next. Progress in circulation and water exchange dynamics has been achieved mostly by means of numerical studies. While the basic properties of circulation patterns in the gulf have been known for a century, new characteristics and tools such as water age, renewal index, and high-resolution simulations have substantially enriched our knowledge of processes in the Gulf of Finland during the last decade. We present the first overview of both status and advances in optical studies in this area. Awareness in this discipline has been significantly improved as a result of in situ measurements. Our understanding of the short- and long-term behaviour of the sea level as well as knowledge of the properties of both naturally and anthropogenically induced surface waves have expanded considerably during these ten years. Developments in understanding the ice conditions of the Gulf of Finland complete the overview, together with a short discussion of the gulf's future, including the response to climate change. Suggestions for future work are outlined.
EN
The response of semi-realistic wind speed increase scenarios to the mean sea level and current regime of semi-enclosed sub-basins in the Baltic Sea is studied with a 2D hydrodynamic model. According to the model output of spatial mean sea levels, an increase in the westerly wind component by 2 m s-1 leads, for example, to a mean sea level rise of up to 3 cm in windward locations in the study area. The sea level change patterns depend on the wind scenario and coastline configuration. The increases in wind speed considered here also lead to enhanced water exchange through the straits, strengthening of the basin-scale circulation, enhancement of up- and downwelling, and increased bottom stresses near coasts.
19
Content available remote Contribution of long-term tide components to sea level variations
EN
Some long-term sea level fluctuations at the Świnoujście gauging station reflect periodicities consistent with long-term components of the tidal forces of the moon and the sun as well as the planets. This paper presents results of a spectral analysis of monthly-normalized sea level values. Their relations with the long-term tidal force potential were determined. They can be the primary cause of sea level fluctuations.
EN
Sediments, carbon-datings on seashells, allow us to reconstruct the evolution of the average sea level for some 6000 years on the Taman Peninsula. The current sea level, regionally, appears to be the highest level ever reached on the peninsula. It seems that for the Anapa area and Tchouchtchka Spit area it is possible to propose a sea level curve characterised by a slow, continuous rising during the past 6000 years. On the Taman Peninsula itself, the sedimentary record of this slow ascent has been distorted by a heavy tectonic subsidence. We have identified this neo-tectonic subsidence effect on at least two areas on the peninsula. The south of the peninsula, Burgaz Spit and Vityazevos Lagoon, is the most affected area. The Taman Gulf is an intermediate area. The tectonic subsidence is particularly noticeable from 1500 to 500 BC, which we believe to have been misinterpreted until now, and to be at the origin of the notion of "Phanagorian Regression".
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