scholarly journals SEA LEVEL CHANGES ALONG THE COASTS OF KEA ISLAND AND PALEOGEOGRAPHICAL COASTAL RECONSTRUCTION OF ARCHAEOLOGICAL SITES

2017 ◽  
Vol 43 (1) ◽  
pp. 453 ◽  
Author(s):  
N.D Mourtzas
Keyword(s):  
Sea Level ◽  
Human Activity ◽  
Human Activities ◽  
Archaeological Sites ◽  
Classical Period ◽  
Sea Level Changes ◽  
Coastal Morphology ◽  
Sea Levels

Sea level changes during the Upper Holocene submerged the coasts of Kea in three different phases about 5.50m, 3.90m and 1.50m respectively below the contemporary sea level thus causing sea transgression along the shores of Kea, which varied from 8m to 78m depending on the coastal morphology. These changes caused the alteration of the earlier morphology at coastal archaeological sites of the Island, as the prehistoric settlement of Ayia Irini and Classical period port of Karthaia, as well as, submerged under the sea areas of coastal human activity during antiquity, as the ancient schist quarry at Spathi bay. The study of historical, geomorphological and sedimentological data indicative of previous sea levels allow the paleogeographical reconstruction of the coasts during the period of human activities in these areas.

scholarly journals Atmospheric circulation changes and their impact on extreme sea levels around Australia

2019 ◽  
Vol 19 (5) ◽  
pp. 1067-1086 ◽  
Author(s):  
Frank Colberg ◽  
Kathleen L. McInnes ◽  
Julian O'Grady ◽  
Ron Hoeke
Keyword(s):  
Sea Level ◽  
Large Scale ◽  
Climate Models ◽  
Tide Gauge ◽  
Austral Summer ◽  
Sea Level Changes ◽  
Sea Level Variability ◽  
Sea Levels ◽  
Extreme Sea Levels ◽  
Coastal Sea

Abstract. Projections of sea level rise (SLR) will lead to increasing coastal impacts during extreme sea level events globally; however, there is significant uncertainty around short-term coastal sea level variability and the attendant frequency and severity of extreme sea level events. In this study, we investigate drivers of coastal sea level variability (including extremes) around Australia by means of historical conditions as well as future changes under a high greenhouse gas emissions scenario (RCP 8.5). To do this, a multi-decade hindcast simulation is validated against tide gauge data. The role of tide–surge interaction is assessed and found to have negligible effects on storm surge characteristic heights over most of the coastline. For future projections, 20-year-long simulations are carried out over the time periods 1981–1999 and 2081–2099 using atmospheric forcing from four CMIP5 climate models. Changes in extreme sea levels are apparent, but there are large inter-model differences. On the southern mainland coast all models simulated a southward movement of the subtropical ridge which led to a small reduction in sea level extremes in the hydrodynamic simulations. Sea level changes over the Gulf of Carpentaria in the north are largest and positive during austral summer in two out of the four models. In these models, changes to the northwest monsoon appear to be the cause of the sea level response. These simulations highlight a sensitivity of this semi-enclosed gulf to changes in large-scale dynamics in this region and indicate that further assessment of the potential changes to the northwest monsoon in a larger multi-model ensemble should be investigated, together with the northwest monsoon's effect on extreme sea levels.

scholarly journals Relative sea-level changes in crete: reassessment of radiocarbon dates from Sphakia and west Crete

2002 ◽  
Vol 97 ◽  
pp. 171-200 ◽  
Author(s):  
Simon Price ◽  
Tom Higham ◽  
Lucia Nixon ◽  
Jennifer Moody
Keyword(s):  
Sea Level ◽  
Late Antiquity ◽  
Isotopic Fractionation ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Sea Levels ◽  
Catastrophic Earthquake ◽  
Radiocarbon Data ◽  
Calendar Dates

This article is concerned with the recognition and dating of Holocene relative sea-level changes along the coast of west Crete (an island located in the active Hellenic subduction arc of the southern Aegean) and in particular in Sphakia. Radiocarbon data for changes in sea levels collected and analysed previously must (a) be recorrected to take into account isotopic fractionation, and (b) recalibrated by using the new marine reservoir value. These new radiocarbon dates are analysed using Bayesian statistics. The resulting calendar dates for changes in sea level are younger than previously assumed. In particular the Great Uplift in western Crete in late antiquity must be dated to the fifth or sixth century AD, not to AD 365. Moreover, recent work on tectonics suggests that the Great Uplift need not have been accompanied by a catastrophic earthquake. Finally, we consider the consequences of the Great Uplift for some coastal sites in Sphakia.

Venice lagoon salt marsh vulnerability and halophytic vegetation vertical migration in response to sea level rise

2020 ◽  
Author(s):  
Zhicheng Yang ◽  
Sonia Silvestri ◽  
Marco Marani ◽  
Andrea D’Alpaos
Keyword(s):  
Salt Marsh ◽  
Sea Level Rise ◽  
Sea Level ◽  
Salt Marshes ◽  
Current Knowledge ◽  
Venice Lagoon ◽  
Sea Level Changes ◽  
Human Pressure ◽  
Sea Levels ◽  
Vegetation Species

<p>Salt marshes are biogeomorphic systems that provide important ecosystem services such as carbon sequestration and prevention of coastal erosion. These ecosystems are, however, threatened by increasing sea levels and human pressure. Improving current knowledge of salt-marsh response to changes in the environmental forcing is a key step to understand and predict salt-marsh evolution, especially under accelerated sea level rise scenarios and increasing human pressure. Towards this goal, we have analyzed field observations of marsh topographic changes and halophytic vegetation distribution with elevation collected over 20 years (between 2000 and 2019) in a representative marsh in the Venice lagoon (Italy).</p><p>Our results suggest that: 1) on average, marsh elevation with respect to local mean sea level decreased , (i.e. the surface accretion rate was lower than the rate of sea level rise); 2) elevational frequency distributions are characteristic for different halophytic vegetation species, highlighting different ecological realized niches that change in time; 3) although the preferential elevations at which different species have changed in time, the sequence of vegetation species with increasing soil elevation was preserved and simply shifted upward; 4) we observed different vegetation migration rates for the different species, suggesting that the migration process is species-specific. In particular, vegetation species colonizing marsh edges (Juncus and Inula) migrated faster facing to changes in sea levels than Limonium and Spartina , while Sarcocornia was characterized by delayed migration in response to sea level changes. These results bear significant implications for long-term biogeomorphic evolution of tidal environments.</p>

The sedimentary record of climatic variation in the southern North Sea

1988 ◽  
Vol 318 (1191) ◽  
pp. 523-537 ◽  
Keyword(s):  
Sea Level ◽  
North Sea ◽  
Climatic Changes ◽  
Sea Level Changes ◽  
Offshore Area ◽  
Sea Levels ◽  
Indirect Response ◽  
Southern North Sea ◽  
Sedimentary Sequences ◽  
Glaciofluvial Deposits

The sedimentary sequence on the shelf of the southern North Sea records Quaternary climatic changes in two ways. They are indicated directly by moraine and glaciofluvial deposits from the Elsterian, Saalian and Weichselian glacial periods when the British and the Scandinavian ice sheets covered parts of the area. An indirect response to the climate is indicated by sea-level changes. Phases of cooling are characterized by regressions and low sea-level stands; phases of warming are indicated by marine transgressions and high sea levels during the Holsteinian, Eemian and Holocene periods. The seismic characteristics of the different lithological units, the sedimentary sequences and their fossil content are described for the offshore area and the adjacent coastal zone. This provides a record of the interaction of sedimentary processes and the palaeogeographic development as a response to climatic changes.

Holocene relative sea levels and coastal changes in the lower Cree valley and estuary, SW Scotland, U.K.

2002 ◽  
Vol 93 (4) ◽  
pp. 301-331 ◽  
Author(s):  
D. E. Smith ◽  
J. M. Wells ◽  
T. M. Mighall ◽  
R. A. Cullingford ◽  
L. K. Holloway ◽  
...  
Keyword(s):  
Sea Level ◽  
Early Holocene ◽  
Coastal Geomorphology ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels ◽  
Coastal Changes

ABSTRACTChanges in Holocene (Flandrian) relative sea levels and coastal geomorphology in the lower Cree valley and estuary, SW Scotland, are inferred from detailed morphological and stratigraphical investigations. A graph of relative sea level changes is proposed for the area. Rising relative sea levels during the early Holocene were interrupted at c. 8300–8600 14C years B.P.(c. 9400–9900 calibrated years B.P.), when an extensive estuarine surface was reached at c. −1 m O.D., after which a fluctuating rise culminated at c. 6100–6500 14C B.P. (c. 7000–7500 calibrated years B.P.) in a prominent shoreline and associated estuarine surface measured at 7·7–10·3 m O.D. A subsequent fall in relative sea level was followed by a rise to a shoreline at 7·8–10·1 m O.D., exceeding or reoccupying the earlier shoreline over much of the area after c. 5000 14C B.P. (c. 5,800 calibrated years B.P.), before relative sea level fell to a later shoreline, reached after c. 2900 14C B.P. (c. 3100 calibrated years B.P.) at 5·5–8·0 m O.D., following which relative sea levels fell, ultimately reaching present levels. During these changes, a particular feature of the coastline was the development of a number of barrier systems. The relative sea level changes identified are compared with changes elsewhere in SW Scotland and their wider context is briefly considered.

scholarly journals Low-End Probabilistic Sea-Level Projections

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1507 ◽  
Author(s):  
Gonéri Le Cozannet ◽  
Rémi Thiéblemont ◽  
Jeremy Rohmer ◽  
Déborah Idier ◽  
Jean-Charles Manceau ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Coupled Model ◽  
Climate Mitigation ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Intercomparison Project ◽  
Business As Usual ◽  
Change Mitigation ◽  
Selection Of

In the area of sea-level rise, recent research has focused on assessing either likely or high end future sea levels, but less attention has been given to “low-end” sea-level projections, exploring best-case potential sea-level changes and providing the basis for estimating minimum adaptation needs. Here, we provide global and regional probabilistic sea-level projections using conservative projections of glaciers and ice-sheets melting and a selection of models from the Coupled Model Intercomparison Project phase 5 (CMIP5) delivering moderate thermal expansion. Our low-end sea-level projections are higher than previously estimated because they rely on modeling outcomes only, and do not add any expert judgement, aiming essentially at delivering more realistic upper tails. While there are good reasons to believe that our projections are excessively optimistic, they can be used as low-end sea-level projections in order to inform users with low aversion to uncertainty. Our low-end sea-level projection exceeds 0.5 m along most inhabited coasts by 2100 for business as usual greenhouse gas emissions (RCP8.5), which is relevant for adaptation practitioners as long as efficient climate change mitigation policies are not implemented. This means that without efficient climate mitigation, an acceleration of sea-level rise can hardly be avoided during the 21st century.

Influence of the "Hypsithermal Age" and "Neoglaciation" climatic conditions on the Brazilian coast.

2001 ◽  
Vol 28 (2) ◽  
pp. 213 ◽  
Author(s):  
KENITIRO SUGUIO
Keyword(s):  
United States ◽  
Gulf Of Mexico ◽  
Sea Level ◽  
Southeastern United States ◽  
Climatic Conditions ◽  
Brazilian Coast ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Sea Levels ◽  
The Past

Meanwhile the highest relative sea-level is the present one in southeastern United States (Gulf of Mexico) or in Netherlands coast, most of the Brazilian coast exhibited Holocene sea-levels higher than the present in the past. The Brazilian curves, representing the relative sea-level changes during last 7.000 years, are outlined using sedimentological, biological and prehistorical past sea-level records. This paper shows that these relative sea-level records, during the Holocene, can be suitably used to demonstrate the influence of the worldwide known paleoclimatic events, like the “Hypsithermal Age” and “Neoglaciation” on the Brazilian coast.

Distribution and palaeogeography of two Mallee species of Eucalyptus in Southern Australia

1969 ◽  
Vol 17 (2) ◽  
pp. 323 ◽  
Author(s):  
RF Parsons
Keyword(s):  
Sea Level ◽  
Animal Species ◽  
Continuous Distribution ◽  
Effective Rainfall ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Plain Area ◽  
Rising Sea Levels

The present distributions of Eucalyptus diversifolia and E. incrassata are described and disjunctions indicated. It is suggested that a former continuous distribution of both species has been fragmented by rising sea-levels in the Quaternary, and that E. diversifolia was more widespread during a period of lower effective rainfall than the present. It is proposed that Quaternary sea-level changes are of importance in the interpretation of the palaeogeography of plant and animal species with disjunctions in the Nullarbor and Roe Plain area. The nature and role of edaphic barriers to migration in this area are also assessed.

Sea-level change and the archaeology of early Venice

Antiquity ◽  
1999 ◽  
Vol 73 (280) ◽  
pp. 303-312 ◽  
Author(s):  
A. J. Ammerman ◽  
C. E. McClennen ◽  
M. de Min ◽  
R. Housley
Keyword(s):  
Sea Level ◽  
Sea Level Change ◽  
Archaeological Sites ◽  
Archaeological Investigation ◽  
Sea Levels ◽  
Level Change ◽  
The Subject ◽  
Rising Sea Levels ◽  
New Evidence ◽  
Insight Into

The threatened city of Venice, plauged by rising sea levels and subsiding ground, has been the subject of recent archaeological investigation. Studies of buried archaeological sites yield new evidence on trends in sea-level change for the Lagoon of Venice and provide important insight into how early habitation responded to such change.

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