scholarly journals Διαχρονική παρατήρηση των μεταβολών της ακτογραμμής τμήματος της παράκτιας ζώνης του νόμου Πιερίας και εκτίμηση των επιπτώσεων από την μελλοντική άνοδο της θαλάσσιας στάθμης

2005 ◽  
Vol 38 ◽  
pp. 182
Author(s):  
Κ. ΤΣΑΝΑΚΑΣ ◽  
Ε. ΚΑΡΥΜΠΑΛΗΣ ◽  
Ι. ΠΑΡΧΑΡΙΔΗΣ

The aim of this study is to detect shoreline changes along part of the coastal zone of Piena during the time period between 1969 and 2000 using aerial photographs and satellite images. Additionally, a quantitative and qualitative assessment of the future sea-level rise (triggered by the global climate change) implications to the physical and socioeconomic environment of the area is attempted taking into account various sea-level rise scenarios. Retreating as well as prograding regions along the study area were defined and retreating/prograding rates for the time periods 1969-1987 and 1987-2000 were estimated using GIS and Remote Sensing techniques. Building activity rates for the coastal area of Paralia Katerinis were also estimated for the same periods. The coastline of the study area is retreating^ except than the area north of torrent Mavroneri where a progradation rate of 48 cm/year was estimated between 1969 and 1987. Retreating rate of the coast for the northern part of the area (Saltworks) is estimated to be 25 cm/year and 19 cm/yrear for the periods of 1969-1987 and 1987-2000 respectively. The broader study area is particularly vulnerable to a potential future sealevel rise due to the low-lying topography of the coastal zone and intensive socioeconomic activities such as tourism and commerce.

2013 ◽  
Vol 16 (1) ◽  
pp. 104-113 ◽  

<p>The present study investigates recent and future evolution of the beach zone of Almiros Bay, one of the most touristic developed beaches of north Crete, in relation to its morphodynamic setting and the anticipated sea level rise. The beach zone is exposed to northerly winds, with maximum wave heights and periods of 4.3 m and 9 s, respectively. The comparison of the aerial photographs (1982-1996) and a satellite image of 2007 have revealed an extended retreat of the beach zone, with its highest retreating rates (i.e. 0.6-0.8 m y-1 for the last 25 years) found at its central part. Moreover, an estimation of the future shoreline retreat, due to the anticipated sea level rise (i.e. 0.38 or 1 m for the year 2100), has shown that there is a potential coastal zone loss from 48% up to 100%, respectively. A gross evaluation of the economical impact due to the aforementioned beach loss accounts to approximately from $ 270,000 up to $ 720.000, annually.</p>


2021 ◽  
Author(s):  
Niki Evelpidou ◽  
Alexandros Petropoulos ◽  
Anna Karkani ◽  
Giannis Saitis

&lt;p&gt;Coastal areas include various landforms, such as dunes, lagoons and wetlands, which constitutes them as areas of particular environmental and geomorphological values. Coastal lagoons and dunes are of great environmental importance, given that, among others, they provide habitat for rare species of flora and fauna, but they also contribute to the protection of the coastal zone from sea level rise, storms, etc. Although these features are unique elements for sustainable development and are of great importance to the natural environment and economy, due to their relatively small size, they are one of the most vulnerable and threatened ecosystems. Such a case is the western coast of Naxos Island, hosting several wetlands bordering with low-lying sand dunes.&lt;/p&gt;&lt;p&gt;Naxos island lies in the center of the Aegean Sea, being part of the Cyclades Island group. The western coasts of Naxos include a number of natural features, which have been inherited from their palaeogeographical evolution over the last 10,000 years. Typically, the western coastal zone is composed of a sandy beach, bordered by low lying sand dunes, lagoons and an alluvial plain. These systems are becoming increasingly vulnerable, due to natural processes such as intensity of waves, but also due to human interventions that have blocked sediment input to the coastal zone and the increasing touristic development. The erosion of the dunes, the intense storms, the sea level rise, extreme events such as storms or tsunamis, and the increased tourist &quot;raid&quot;, will lead to marine flooding not only to the beach, but also to the lagoons and many acres of land (rural, residential areas).&lt;/p&gt;&lt;p&gt;The aim of our study is to assess the vulnerability of the western coasts of Naxos to sea level rise, considering both natural and anthropogenic pressures. For this purpose, we used a series of methodologies for the environmental and geomorphological study of the coastal zone and the shallow submarine area, which included: a) photointerpretation of aerial photographs from 1960 until today, b) systematic seasonal aerial monitoring by drone, since 2015, c) mapping of the coastal zone and topographic sections using DGPS and d) dune mapping and sampling, e) sampling of underwater beachrocks. Through our analysis we aim to better elucidate the impact of the relative sea level rise in the study area.&lt;/p&gt;


2016 ◽  
Vol 10 (3) ◽  
pp. 1147-1159 ◽  
Author(s):  
Andreas Bech Mikkelsen ◽  
Alun Hubbard ◽  
Mike MacFerrin ◽  
Jason Eric Box ◽  
Sam H. Doyle ◽  
...  

Abstract. It has been argued that the infiltration and retention of meltwater within firn across the percolation zone of the Greenland ice sheet has the potential to buffer up to  ∼  3.6 mm of global sea-level rise (Harper et al., 2012). Despite evidence confirming active refreezing processes above the equilibrium line, their impact on runoff and proglacial discharge has yet to be assessed. Here, we compare meteorological, melt, firn stratigraphy and discharge data from the extreme 2010 and 2012 summers to determine the relationship between atmospheric forcing and melt runoff at the land-terminating Kangerlussuaq sector of the Greenland ice sheet, which drains into the Watson River. The 6.8 km3 bulk discharge in 2012 exceeded that in 2010 by 28 %, despite only a 3 % difference in net incoming melt energy between the two years. This large disparity can be explained by a 10 % contribution of runoff originating from above the long-term equilibrium line in 2012 caused by diminished firn retention. The amplified 2012 response was compounded by catchment hypsometry; the disproportionate increase in area contributing to runoff as the melt-level rose high into the accumulation area.Satellite imagery and aerial photographs reveal an extensive supraglacial network extending 140 km from the ice margin that confirms active meltwater runoff originating well above the equilibrium line. This runoff culminated in three days with record discharge of 3100 m3 s−1 (0.27 Gt d−1) that peaked on 11 July and washed out the Watson River Bridge. Our findings corroborate melt infiltration processes in the percolation zone, though the resulting patterns of refreezing are complex and can lead to spatially extensive, perched superimposed ice layers within the firn. In 2012, such layers extended to an elevation of at least 1840 m and provided a semi-impermeable barrier to further meltwater storage, thereby promoting widespread runoff from the accumulation area of the Greenland ice sheet that contributed directly to proglacial discharge and global sea-level rise.


2013 ◽  
Vol 26 (8) ◽  
pp. 2502-2513 ◽  
Author(s):  
N. Bouttes ◽  
J. M. Gregory ◽  
J. A. Lowe

Abstract During the last century, global climate has been warming, and projections indicate that such a warming is likely to continue over coming decades. Most of the extra heat is stored in the ocean, resulting in thermal expansion of seawater and global mean sea level rise. Previous studies have shown that after CO2 emissions cease or CO2 concentration is stabilized, global mean surface air temperature stabilizes or decreases slowly, but sea level continues to rise. Using idealized CO2 scenario simulations with a hierarchy of models including an AOGCM and a step-response model, the authors show how the evolution of thermal expansion can be interpreted in terms of the climate energy balance and the vertical profile of ocean warming. Whereas surface temperature depends on cumulative CO2 emissions, sea level rise due to thermal expansion depends on the time profile of emissions. Sea level rise is smaller for later emissions, implying that targets to limit sea level rise would need to refer to the rate of emissions, not only to the time integral. Thermal expansion is in principle reversible, but to halt or reverse it quickly requires the radiative forcing to be reduced substantially, which is possible on centennial time scales only by geoengineering. If it could be done, the results indicate that heat would leave the ocean more readily than it entered, but even if thermal expansion were returned to zero, the geographical pattern of sea level would be altered. Therefore, despite any aggressive CO2 mitigation, regional sea level change is inevitable.


1993 ◽  
Vol 30 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Philip R. Hill ◽  
Arnaud Héquette ◽  
Marie-Hélène Ruz

New radiocarbon ages pertaining to the Holocene sea-level history of the Canadian Beaufort shelf are presented. The ages were obtained on samples of freshwater and tidal-marsh peat beds from offshore boreholes and shallow cores in the coastal zone and on molluscs and a single piece of wood deposited in foraminifera-bearing marine sediments. Although none of the samples record directly the position of relative sea level, the suite of ages constrains the regional curve sufficiently to suggest a faster rate of mid Holocene sea level rise (7–14 mm/a) than previously thought. The rate of relative rise slowed markedly in the last 3000 years, approaching the present at a maximum probable rate of 2.5 mm/a.


2015 ◽  
Vol 19 (2) ◽  
pp. 227-240 ◽  
Author(s):  
Adrián Pedrozo-Acuña ◽  
Richard Damania ◽  
Miguel A. Laverde-Barajas ◽  
Daniel Mira-Salama

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