Sea level changes along the turkish coasts of the Black Sea, the Aegean Sea and the Eastern Mediterranean (original) (raw)

Internal and external forcing of sea level variability in the Black Sea

Climate Dynamics, 2015

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Dynamic response of the Black Sea elevation to intraseasonal fluctuations of the Mediterranean sea level

Response of the Black Sea elevation to intraseasonal sea level changes in the Mediterranean is studied using satellite altimetry data and a linear analytical model. Satellite observations show that the nonseasonal sea level in the Black Sea (η 1) is coherent with that in the Aegean and Marmara Seas (η 0) but lags behind them by 10–40 days at subannual periods. The observed time lag is mainly due to friction that constrains the exchange through the Bosphorus Strait. Using realistic friction and characteristic η 0 forcing in the model, we find that the amplitude of η 1 reaches the amplitude of η 0 at about 1 year period, and the time lag increases from 10 to 22 days at periods 50–250 days. Freshwater fluxes, atmospheric pressure, and to a smaller extent the along-strait wind also influence the Black Sea elevation, but sea level fluctuations in the Mediterranean appear to be the dominant forcing mechanism.

Investigaton of Sea Level Change Along the Black Sea Coast from Tide Gauge and Satellite Altimetry

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2015

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 ...

Sea level variability at Antalya and Menteş tide gauges in Turkey: atmospheric, steric and land motion contributions

Studia Geophysica et Geodaetica, 2012

Sea level trends along the western coasts of Anatolia are investigated during the 1985 -2001 period, quantifying the roles of atmospheric, steric and local land motion contributions to these trends. Tide gauge measurements, temperature/salinity climatologies and GPS data are used in the analyses and the results are compared with the output of a barotropic model forced by atmospheric pressure and wind. Atmospheric and steric contributions to interannual sea level variability are also explored. Two tide gauges collocated with GPS indicate sea level trends of 5.5 to 7.9 mm/yr. After the removal of the atmospheric forcing and steric contribution from sea level records, the resulting trends are 1.2 ± 0.7 mm/yr in Menteş, and 3.2 ± 0.6 mm/yr in Antalya tide gauges which are mostly explained by local land motions estimated from GPS data.

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

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 10 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 15

On the forcing of sea level in the Black Sea

Journal of Geophysical Research, 2004

1] Forcing mechanisms for sea level variability in the Black Sea are investigated in the context of an observed increase in the sea level of this basin by 2.5 mm/yr over the last 60 years. Temperature and salinity variations computed from the Mediterranean Data Archeology and Rescue (MEDAR) data set exhibit significant interdecadal variability. However, the corresponding steric height variation does not show a long-term increase and thus cannot account for the observed change in sea level. The impact of surface freshwater flux (P-E) changes is also investigated using two independent data sets. The first data set, which is based on measurements collected in the basin, can explain most of the sea level variability, with only 0.8 mm/yr remaining unexplained. The second data set, output from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis, is unable to explain any of the observed trend. Potential contributions from changes in river runoff and surface pressure are quantified but found to be minor terms. By comparing the observed salinity changes with the sea level rise and the P-E variability in the first data set, we infer that the P-E variations are the primary cause for the observed sea level rise, while land movements are likely to partly contribute, too. The relationship of Black Sea temperature and salinity variability with corresponding variability in the connected Aegean Sea has also been explored. A significant correlation is found between the salinity of the upper water of the Aegean Sea and the layer between 50 and 300 m in the Black Sea, indicating that the latter layer is a product of the Mediterranean inflow.

Trend Analysis of Sea Levels Along Turkish Coast

2007

Sea level changes can be considered as an indicator of environmental and climate change. Sea level becomes a factor of anxiety to those who fear the possible consequences of the earth warmed as a result of the buildup of greenhouse gases. Despite the cities along coastal lines cover less than five percent of the total surface area of Turkey; their total population is over 30 million with a rapid growing rate. A significant change in sea levels is extremely important to the coastal communities in Turkey. In literature, linear secular trends in annual mean sea level data are calculated as the least squares linear regression to a bivariate distribution of the data value versus year. The length of the time series is recommended to be 60 years or longer which sometimes is permitted to be as low as 25 years. In this study, we use a nonparametric approach to determine trends in sea levels as the available data comprises of rather short record length. At the same time, the nonparametric methods are more tolerable for the short records, computationally simpler and distribution-free. Therefore we investigated trend behaviors in sea level data measured along the Mediterranean, Aegean and Black Sea coasts of Turkey using nonparametric Mann-Kendall test. Annual sea level records, observed for eight typical stations, were used for the purpose of trend detection. As a result, five out of eight stations showed an upward trend as one of them showed a downward trend. No trend was found for the remaining stations. We also fitted a least squared line to quantify rate of change in seal level. Among the stations showing positive trends, the highest rate of change was computed in Trabzon (the Black Sea station) whereas the lowest was computed in Kar ıyaka (the Aegean Sea station). The results confirmed a strong signal of sea level rise at global scale.

Trend analysis of sea levels along Turkish coasts

wsprod.colostate.edu

Sea level changes can be considered as an indicator of environmental and climate change. Sea level becomes a factor of anxiety to those who fear the possible consequences of the earth warmed as a result of the buildup of greenhouse gases. Despite the cities along coastal lines cover less than five percent of the total surface area of Turkey; their total population is over 30 million with a rapid growing rate. A significant change in sea levels is extremely important to the coastal communities in Turkey. In literature, linear secular trends in annual mean sea level data are calculated as the least squares linear regression to a bivariate distribution of the data value versus year. The length of the time series is recommended to be 60 years or longer which sometimes is permitted to be as low as 25 years. In this study, we use a nonparametric approach to determine trends in sea levels as the available data comprises of rather short record length. At the same time, the nonparametric methods are more tolerable for the short records, computationally simpler and distribution-free. Therefore we investigated trend behaviors in sea level data measured along the Mediterranean, Aegean and Black Sea coasts of Turkey using nonparametric Mann-Kendall test. Annual sea level records, observed for eight typical stations, were used for the purpose of trend detection. As a result, five out of eight stations showed an upward trend as one of them showed a downward trend. No trend was found for the remaining stations. We also fitted a least squared line to quantify rate of change in seal level. Among the stations showing positive trends, the highest rate of change was computed in Trabzon (the Black Sea station) whereas the lowest was computed in Kar ıyaka (the Aegean Sea station). The results confirmed a strong signal of sea level rise at global scale.

Seasonal Dynamics of the System Sea-Strait: Black Sea–Bosphorus Case Study

Estuarine, Coastal and Shelf Science, 2002

The seasonal behaviour of the Black Sea-Bosphorus system is studied. The one-and-a-half-dimensional model of the Black Sea is used. It describes the level and thermohaline structure changes of the sea. A one-layer sub-model is used for the shallow Azov Sea. The Black Sea model is driven by the seasonal wind, heat flux, freshwater influx and bottom Bosphorus current. A quasi-stationary hydraulic two-layer model of the long strait with bottom and interface friction is used for Bosphorus. As opposed to most of the earlier models, it simulates exchange in terms of the level difference along the strait instead of net barotropic transport. The simulations show that the model is able to describe seasonal variations of the vertical structure of the Black Sea including cold intermediate layer (CIL) formation. A set of experiments was carried out to clarify the relative importance of seasonality of main forcing mechanisms (freshwater influx, heat budget, wind and level in the Marmara Sea) on the Black Sea vertical structure and strait exchange. The Black Sea level follows mainly in the freshwater influx with a delay of 2 months. The dependence of the volumetric flow rates in the upper and bottom layers of the strait on the level difference at the strait ends is close to linear. The simulations demonstrate sensitivity of exchange through the Bosphorus on the seasonal variations of the Marmara Sea level.