WorldWideScience

Sample records for local sea level

  1. Sea-level rise: towards understanding local vulnerability

    Science.gov (United States)

    Rahmstorf, Stefan

    2012-06-01

    , experts are increasingly looking at its potential impacts on coasts to facilitate local adaptation planning. This is a more complex issue than one might think, because different stretches of coast can be affected in very different ways. First of all, the sea-level response to global warming will not be globally uniform, since factors like changes in ocean currents (Levermann et al 2005) and the changing gravitational pull of continental ice (Mitrovica et al 2001) affect the local rise. Secondly, superimposed on the climatic trend is natural variability in sea level, which regionally can be as large as the climatic signal on multi-decadal timescales. Over the past decades, sea level has dropped in sizable parts of the world ocean, although it has of course risen in global mean (IPCC 2007). Thirdly, local land uplift or subsidence affects the local sea-level change relative to the coast, both for natural reasons (post-glacial isostatic adjustment centred on regions that were covered by ice sheets during the last ice age) and artificial ones (e.g., extraction of water or oil as in the Gulf of Mexico). Finally, local vulnerability to sea-level rise depends on many factors. Two interesting new studies in this journal (Tebaldi et al 2012, Strauss et al 2012) make important steps towards understanding sea-level vulnerability along the coasts of the United States, with methods that could also be applied elsewhere. The first, by Strauss and colleagues, merges high-resolution topographic data and a newly available tidal model together with population and housing data in order to estimate what land area and population would be at risk given certain increments in sea level. The results are mapped and tabulated at county and city level. They reveal the 'hot spots' along the US coast where sea-level rise is of the highest concern because of large populations living near the high-tide line: New York City and Long Island; the New Jersey shore; the Norfolk, Virginia, area; near Charleston

  2. Tidal marsh susceptibility to sea-level rise: importance of local-scale models

    Science.gov (United States)

    Thorne, Karen M.; Buffington, Kevin J.; Elliott-Fisk, Deborah L.; Takekawa, John Y.

    2015-01-01

    Increasing concern over sea-level rise impacts to coastal tidal marsh ecosystems has led to modeling efforts to anticipate outcomes for resource management decision making. Few studies on the Pacific coast of North America have modeled sea-level rise marsh susceptibility at a scale relevant to local wildlife populations and plant communities. Here, we use a novel approach in developing an empirical sea-level rise ecological response model that can be applied to key management questions. Calculated elevation change over 13 y for a 324-ha portion of San Pablo Bay National Wildlife Refuge, California, USA, was used to represent local accretion and subsidence processes. Next, we coupled detailed plant community and elevation surveys with measured rates of inundation frequency to model marsh state changes to 2100. By grouping plant communities into low, mid, and high marsh habitats, we were able to assess wildlife species vulnerability and to better understand outcomes for habitat resiliency. Starting study-site conditions were comprised of 78% (253-ha) high marsh, 7% (30-ha) mid marsh, and 4% (18-ha) low marsh habitats, dominated by pickleweed Sarcocornia pacifica and cordgrass Spartina spp. Only under the low sea-level rise scenario (44 cm by 2100) did our models show persistence of some marsh habitats to 2100, with the area dominated by low marsh habitats. Under mid (93 cm by 2100) and high sea-level rise scenarios (166 cm by 2100), most mid and high marsh habitat was lost by 2070, with only 15% (65 ha) remaining, and a complete loss of these habitats by 2080. Low marsh habitat increased temporarily under all three sea-level rise scenarios, with the peak (286 ha) in 2070, adding habitat for the endemic endangered California Ridgway’s rail Rallus obsoletus obsoletus. Under mid and high sea-level rise scenarios, an almost complete conversion to mudflat occurred, with most of the area below mean sea level. Our modeling assumed no marsh migration upslope due to human

  3. Allowances for evolving coastal flood risk under uncertain local sea-level rise

    Science.gov (United States)

    Buchanan, M. K.; Kopp, R. E.; Oppenheimer, M.; Tebaldi, C.

    2015-12-01

    Sea-level rise (SLR) causes estimates of flood risk made under the assumption of stationary mean sea level to be biased low. However, adjustments to flood return levels made assuming fixed increases of sea level are also inaccurate when applied to sea level that is rising over time at an uncertain rate. To accommodate both the temporal dynamics of SLR and their uncertainty, we develop an Average Annual Design Life Level (AADLL) metric and associated SLR allowances [1,2]. The AADLL is the flood level corresponding to a time-integrated annual expected probability of occurrence (AEP) under uncertainty over the lifetime of an asset; AADLL allowances are the adjustment from 2000 levels that maintain current risk. Given non-stationary and uncertain SLR, AADLL flood levels and allowances provide estimates of flood protection heights and offsets for different planning horizons and different levels of confidence in SLR projections in coastal areas. Allowances are a function primarily of local SLR and are nearly independent of AEP. Here we employ probabilistic SLR projections [3] to illustrate the calculation of AADLL flood levels and allowances with a representative set of long-duration tide gauges along U.S. coastlines. [1] Rootzen et al., 2014, Water Resources Research 49: 5964-5972. [2] Hunter, 2013, Ocean Engineering 71: 17-27. [3] Kopp et al., 2014, Earth's Future 2: 383-406.

  4. Reconstruction of Local Sea Levels at South West Pacific Islands—A Multiple Linear Regression Approach (1988-2014)

    Science.gov (United States)

    Kumar, V.; Melet, A.; Meyssignac, B.; Ganachaud, A.; Kessler, W. S.; Singh, A.; Aucan, J.

    2018-02-01

    Rising sea levels are a critical concern in small island nations. The problem is especially serious in the western south Pacific, where the total sea level rise over the last 60 years has been up to 3 times the global average. In this study, we aim at reconstructing sea levels at selected sites in the region (Suva, Lautoka—Fiji, and Nouméa—New Caledonia) as a multilinear regression (MLR) of atmospheric and oceanic variables. We focus on sea level variability at interannual-to-interdecadal time scales, and trend over the 1988-2014 period. Local sea levels are first expressed as a sum of steric and mass changes. Then a dynamical approach is used based on wind stress curl as a proxy for the thermosteric component, as wind stress curl anomalies can modulate the thermocline depth and resultant sea levels via Rossby wave propagation. Statistically significant predictors among wind stress curl, halosteric sea level, zonal/meridional wind stress components, and sea surface temperature are used to construct a MLR model simulating local sea levels. Although we are focusing on the local scale, the global mean sea level needs to be adjusted for. Our reconstructions provide insights on key drivers of sea level variability at the selected sites, showing that while local dynamics and the global signal modulate sea level to a given extent, most of the variance is driven by regional factors. On average, the MLR model is able to reproduce 82% of the variance in island sea level, and could be used to derive local sea level projections via downscaling of climate models.

  5. Sea level change

    Digital Repository Service at National Institute of Oceanography (India)

    Church, J.A.; Clark, P.U.; Cazenave, A.; Gregory, J.M.; Jevrejeva, S.; Levermann, A.; Merrifield, M.A.; Milne, G.A.; Nerem, R.S.; Nunn, P.D.; Payne, A.J.; Pfeffer, W.T.; Stammer, D.; Unnikrishnan, A.S.

    This chapter considers changes in global mean sea level, regional sea level, sea level extremes, and waves. Confidence in projections of global mean sea level rise has increased since the Fourth Assessment Report (AR4) because of the improved...

  6. Risk Analysis of Coastal hazard Considering Sea-level Rise and Local Environment in Coastal Area

    Science.gov (United States)

    Sangjin, P.; Lee, D. K.; KIM, H.; Ryu, J. E.; Yoo, S.; Ryoo, H.

    2014-12-01

    Recently, natural hazards has been more unpredictable with increasing frequency and strength due to climate change. Especially, coastal areas would be more vulnerable in the future because of sea-level rise (SLR). In case of Korea, it is surrounded by oceans and has many big cities at coastal area, thus a hazard prevention plan in coastal area is absolutely necessary. However, prior to making the plan, finding areas at risk would be the first step. In order to find the vulnerable area, local characteristics of coastal areas should also be considered along with SLR. Therefore, the objective of the research is to find vulnerable areas, which could be damaged by coastal hazards considering local environment and SLR of coastal areas. Spatial scope of the research was set up as 1km from the coastline according to the 'coastal management law' in Korea. The assessment was done up to the year of 2050, and the highest sea level rise scenario was used. For risk analysis, biophysical and socioeconomic characteristics were considered as to represent local characteristics of coastal area. Risk analysis was carried out through the combination of 'possibility of hazard' and the 'level of damages', and both of them reflect the above-mentioned regional characteristics. Since the range of inundation was narrowed down to the inundation from typhoon in this research, the possibility of inundation caused by typhoon was estimated by using numerical model, which calculated the height of storm surge considering wave, tide, sea-level pressure and SLR. Also the level of damage was estimated by categorizing the socioeconomic character into four factors; human, infrastructure, ecology and socioeconomic. Variables that represent each factor were selected and used in damage estimation with their classification and weighting value. The result shows that the urban coastal areas are more vulnerable and hazardous than other areas because of socioeconomic factors. The east and the south coast are

  7. Impacts of altimeter corrections on local linear sea level trends around Taiwan

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Andersen, Ole Baltazar

    2013-01-01

    .e. the inverted barometer correction, wet tropospheric correction, and sea state bias correction, have significant impacts on the determination of local LSLT. The trend of default corrections contribute more than 1.4 mm year-1 along the coastline of China mainland and 2.1 mm year-1 to local LSLT in the Taiwan...

  8. Amplification of flood frequencies with local sea level rise and emerging flood regimes

    Science.gov (United States)

    Buchanan, Maya K.; Oppenheimer, Michael; Kopp, Robert E.

    2017-06-01

    The amplification of flood frequencies by sea level rise (SLR) is expected to become one of the most economically damaging impacts of climate change for many coastal locations. Understanding the magnitude and pattern by which the frequency of current flood levels increase is important for developing more resilient coastal settlements, particularly since flood risk management (e.g. infrastructure, insurance, communications) is often tied to estimates of flood return periods. The Intergovernmental Panel on Climate Change’s Fifth Assessment Report characterized the multiplication factor by which the frequency of flooding of a given height increases (referred to here as an amplification factor; AF). However, this characterization neither rigorously considered uncertainty in SLR nor distinguished between the amplification of different flooding levels (such as the 10% versus 0.2% annual chance floods); therefore, it may be seriously misleading. Because both historical flood frequency and projected SLR are uncertain, we combine joint probability distributions of the two to calculate AFs and their uncertainties over time. Under probabilistic relative sea level projections, while maintaining storm frequency fixed, we estimate a median 40-fold increase (ranging from 1- to 1314-fold) in the expected annual number of local 100-year floods for tide-gauge locations along the contiguous US coastline by 2050. While some places can expect disproportionate amplification of higher frequency events and thus primarily a greater number of historically precedented floods, others face amplification of lower frequency events and thus a particularly fast growing risk of historically unprecedented flooding. For example, with 50 cm of SLR, the 10%, 1%, and 0.2% annual chance floods are expected respectively to recur 108, 335, and 814 times as often in Seattle, but 148, 16, and 4 times as often in Charleston, SC.

  9. The role of local and external factors in determining the interannual sea level variability of the Adriatic and Black Seas during the 20th century.

    Science.gov (United States)

    Scarascia, Luca; Lionello, Piero

    2016-04-01

    The Adriatic Sea and the Black Sea are two semienclosed basins connected to the Mediterranean Sea by the Otranto and the Bosporus straits, respectively. This work aims to reconstruction the sea level for both basins in the 20th century and to investigate main sources of interannual variability. Using 7 tide gauge timeseries located along the Adriatic coast and 5 along the Black Sea coast, provided by the PSMSL (Permanent service of mean sea level), a seamless sea level timeseries (1900-2009) has been obtained for each basin on the basis of statistical procedure involving PCA and Least Square Method. The comparison with satellite data in the period 1993 - 2009 confirms that these are reliable representations of the observed sea level for the whole basin, showing a great agreement with a correlation value of 0.87 and 0.72 for Adriatic and Black Sea respectively. The sea level has been decomposed in various contributions in order to analyze the role of the factors responsible for its interannual variability. The annual cycles of the local effect of pressure (inverse barometer effect IB), of the steric effect due to temperature and salinity variation and of the wind effect have been computed. The largest contribute for the Adriatic Sea is due to the wind, whilst inverse barometer effect plays a minor role and the steric effect seems to be almost negligible. For the Black Sea, on the contrary, wind effect is negligible, and the largest source of variability is due to the Danube river, which is estimated from the available discharge data of Sulina (one of the exits of the Danube delta. Steric and IB effects play both a minor role in this basin. A linear regression model, built considering as predictor the SLP gradient identified at large scale after having carried out the correlation analysis, is capable to explain a further percentage of variability (about 20-25%) of the sea level after subtracting all the factors considered above. Finally, residual sea levels show a

  10. Sea level changes induced by local winds on the west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Mehra, P.; Tsimplis, M.N.; Desai, R.G.P.; Joseph, A.; Shaw, A.G.P.; Somayajulu, Y.K.; Cipollini, P.

    1 National Institute of Oceanography, Goa, India 2 National Oceanography Centre, Southampton, UK # [Corresponding author: pmehra@nio.org] Abstract The contribution of atmospheric pressure and wind to sea level variability at Goa (West...), Southampton under an Indian Ocean Tsunami Warning System (IOWTS) fellowship-2008-2009. We are all grateful to the International Oceanographic Commission for providing us with the opportunity of working together. 17 R: Correlation coefficient between sea...

  11. Caribbean Sea Level Network

    Science.gov (United States)

    von Hillebrandt-Andrade, C.; Crespo Jones, H.

    2012-12-01

    requirements and factors have been considered for the sustainability of the stations. The sea level stations have to potentially sustain very aggressive conditions of not only tsunamis, but on a more regular basis, hurricanes. Given the requirement that the data be available in near real time, for tsunami and other coastal hazard application, robust communication systems are also essential. For the local operator, the ability to be able to visualize the data is critical and tools like the IOC Sea level Monitoring Facility and the Tide Tool program are very useful. It has also been emphasized the need for these stations to serve multiple purposes. For climate and other research applications the data need to be archived, QC'd and analyzed. Increasing the user base for the sea level data has also been seen as an important goal to gain the local buy in; local weather and meteorological offices are considered as key stakeholders but for whom applications still need to be developed. The CARIBE EWS continues to look forward to working with other IOC partners including the Global Sea Level Observing System (GLOSS) and Sub-Commission for the Caribbean and Adjacent Regions (IOCARIBE)/GOOS, as well as with local, national and global sea level station operators and agencies for the development of a sustainable sea level network.

  12. Sea level report

    International Nuclear Information System (INIS)

    Schwartz, M.L.

    1979-01-01

    Study of Cenozoic Era sea levels shows a continual lowering of sea level through the Tertiary Period. This overall drop in sea level accompanied the Pleistocene Epoch glacio-eustatic fluctuations. The considerable change of Pleistocene Epoch sea level is most directly attributable to the glacio-eustatic factor, with a time span of 10 5 years and an amplitude or range of approximately 200 m. The lowering of sea level since the end of the Cretaceous Period is attributed to subsidence and mid-ocean ridges. The maximum rate for sea level change is 4 cm/y. At present, mean sea level is rising at about 3 to 4 mm/y. Glacio-eustacy and tectono-eustacy are the parameters for predicting sea level changes in the next 1 my. Glacio-eustatic sea level changes may be projected on the basis of the Milankovitch Theory. Predictions about tectono-eustatic sea level changes, however, involve predictions about future tectonic activity and are therefore somewhat difficult to make. Coastal erosion and sedimentation are affected by changes in sea level. Erosion rates for soft sediments may be as much as 50 m/y. The maximum sedimentation accumulation rate is 20 m/100 y

  13. State and local governments plan for development of most land vulnerable to rising sea level along the US Atlantic coast

    International Nuclear Information System (INIS)

    Titus, J G; Hudgens, D E; Kassakian, J M; Trescott, D L; Craghan, M; Nuckols, W H; Hershner, C H; Linn, C J; Merritt, P G; McCue, T M; O'Connell, J F; Tanski, J; Wang, J

    2009-01-01

    Rising sea level threatens existing coastal wetlands. Overall ecosystems could often survive by migrating inland, if adjacent lands remained vacant. On the basis of 131 state and local land use plans, we estimate that almost 60% of the land below 1 m along the US Atlantic coast is expected to be developed and thus unavailable for the inland migration of wetlands. Less than 10% of the land below 1 m has been set aside for conservation. Environmental regulators routinely grant permits for shore protection structures (which block wetland migration) on the basis of a federal finding that these structures have no cumulative environmental impact. Our results suggest that shore protection does have a cumulative impact. If sea level rise is taken into account, wetland policies that previously seemed to comply with federal law probably violate the Clean Water Act.

  14. Contemporary Arctic Sea Level

    Science.gov (United States)

    Cazenave, A. A.

    2017-12-01

    During recent decades, the Arctic region has warmed at a rate about twice the rest of the globe. Sea ice melting is increasing and the Greenland ice sheet is losing mass at an accelerated rate. Arctic warming, decrease in the sea ice cover and fresh water input to the Arctic ocean may eventually impact the Arctic sea level. In this presentation, we review our current knowledge of contemporary Arctic sea level changes. Until the beginning of the 1990s, Arctic sea level variations were essentially deduced from tide gauges located along the Russian and Norwegian coastlines. Since then, high inclination satellite altimetry missions have allowed measuring sea level over a large portion of the Arctic Ocean (up to 80 degree north). Measuring sea level in the Arctic by satellite altimetry is challenging because the presence of sea ice cover limits the full capacity of this technique. However adapted processing of raw altimetric measurements significantly increases the number of valid data, hence the data coverage, from which regional sea level variations can be extracted. Over the altimetry era, positive trend patterns are observed over the Beaufort Gyre and along the east coast of Greenland, while negative trends are reported along the Siberian shelf. On average over the Arctic region covered by satellite altimetry, the rate of sea level rise since 1992 is slightly less than the global mea sea level rate (of about 3 mm per year). On the other hand, the interannual variability is quite significant. Space gravimetry data from the GRACE mission and ocean reanalyses provide information on the mass and steric contributions to sea level, hence on the sea level budget. Budget studies show that regional sea level trends over the Beaufort Gyre and along the eastern coast of Greenland, are essentially due to salinity changes. However, in terms of regional average, the net steric component contributes little to the observed sea level trend. The sea level budget in the Arctic

  15. Arctic Sea Level Reconstruction

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    Reconstruction of historical Arctic sea level is very difficult due to the limited coverage and quality of tide gauge and altimetry data in the area. This thesis addresses many of these issues, and discusses strategies to help achieve a stable and plausible reconstruction of Arctic sea level from...... 1950 to today.The primary record of historical sea level, on the order of several decades to a few centuries, is tide gauges. Tide gauge records from around the world are collected in the Permanent Service for Mean Sea Level (PSMSL) database, and includes data along the Arctic coasts. A reasonable...... amount of data is available along the Norwegian and Russian coasts since 1950, and most published research on Arctic sea level extends cautiously from these areas. Very little tide gauge data is available elsewhere in the Arctic, and records of a length of several decades,as generally recommended for sea...

  16. Sea level trends in Southeast Asian seas

    Science.gov (United States)

    Strassburg, M. W.; Hamlington, B. D.; Leben, R. R.; Manurung, P.; Lumban Gaol, J.; Nababan, B.; Vignudelli, S.; Kim, K.-Y.

    2015-05-01

    Southeast Asian seas span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian oceans. The Southeast Asian sea regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost 2 decades. Initial comparisons of global sea level reconstructions find that 17-year sea level trends over the past 60 years exhibit good agreement with decadal variability associated with the Pacific Decadal Oscillation and related fluctuations of trade winds in the region. The Southeast Asian sea region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer timescales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past 20 years, the rate of sea level rise is greatly reduced in the Southeast Asian sea region. As a result of the influence of the PDO, the Southeast Asian sea regional sea level trends during the 2010s and 2020s are likely to be less than the global mean sea level (GMSL) trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the Southeast Asian seas will continue to be affected by GMSL rise occurring now and in the future.

  17. Contemporary sea level rise.

    Science.gov (United States)

    Cazenave, Anny; Llovel, William

    2010-01-01

    Measuring sea level change and understanding its causes has considerably improved in the recent years, essentially because new in situ and remote sensing observations have become available. Here we report on most recent results on contemporary sea level rise. We first present sea level observations from tide gauges over the twentieth century and from satellite altimetry since the early 1990s. We next discuss the most recent progress made in quantifying the processes causing sea level change on timescales ranging from years to decades, i.e., thermal expansion of the oceans, land ice mass loss, and land water-storage change. We show that for the 1993-2007 time span, the sum of climate-related contributions (2.85 +/- 0.35 mm year(-1)) is only slightly less than altimetry-based sea level rise (3.3 +/- 0.4 mm year(-1)): approximately 30% of the observed rate of rise is due to ocean thermal expansion and approximately 55% results from land ice melt. Recent acceleration in glacier melting and ice mass loss from the ice sheets increases the latter contribution up to 80% for the past five years. We also review the main causes of regional variability in sea level trends: The dominant contribution results from nonuniform changes in ocean thermal expansion.

  18. Projecting future sea level

    Science.gov (United States)

    Cayan, Daniel R.; Bromirski, Peter; Hayhoe, Katharine; Tyree, Mary; Dettinger, Mike; Flick, Reinhard

    2006-01-01

    California’s coastal observations and global model projections indicate that California’s open coast and estuaries will experience increasing sea levels over the next century. Sea level rise has affected much of the coast of California, including the Southern California coast, the Central California open coast, and the San Francisco Bay and upper estuary. These trends, quantified from a small set of California tide gages, have ranged from 10–20 centimeters (cm) (3.9–7.9 inches) per century, quite similar to that estimated for global mean sea level. So far, there is little evidence that the rate of rise has accelerated, and the rate of rise at California tide gages has actually flattened since 1980, but projections suggest substantial sea level rise may occur over the next century. Climate change simulations project a substantial rate of global sea level rise over the next century due to thermal expansion as the oceans warm and runoff from melting land-based snow and ice accelerates. Sea level rise projected from the models increases with the amount of warming. Relative to sea levels in 2000, by the 2070–2099 period, sea level rise projections range from 11–54 cm (4.3–21 in) for simulations following the lower (B1) greenhouse gas (GHG) emissions scenario, from 14–61 cm (5.5–24 in) for the middle-upper (A2) emission scenario, and from 17–72 cm (6.7–28 in) for the highest (A1fi) scenario. In addition to relatively steady secular trends, sea levels along the California coast undergo shorter period variability above or below predicted tide levels and changes associated with long-term trends. These variations are caused by weather events and by seasonal to decadal climate fluctuations over the Pacific Ocean that in turn affect the Pacific coast. Highest coastal sea levels have occurred when winter storms and Pacific climate disturbances, such as El Niño, have coincided with high astronomical tides. This study considers a range of projected future

  19. Sea level trends in South East Asian Seas (SEAS)

    Science.gov (United States)

    Strassburg, M. W.; Hamlington, B. D.; Leben, R. R.; Manurung, P.; Lumban Gaol, J.; Nababan, B.; Vignudelli, S.; Kim, K.-Y.

    2014-10-01

    Southeast Asian Seas (SEAS) span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian Oceans. The SEAS regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost two decades. Initial comparisons of global sea level reconstructions find that 17 year sea level trends over the past 60 years exhibit good agreement in areas and at times of strong signal to noise associated decadal variability forced by low frequency variations in Pacific trade winds. The SEAS region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer time scales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past twenty years, the rate of sea level rise is greatly reduced in the SEAS region. As a result of the influence of the PDO, the SEAS regional sea level trends during 2010s and 2020s are likely to be less than the global mean sea level (GMSL) trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the SEAS will continue to be affected by GMSL rise occurring now and in the future.

  20. Local level sustainability policies in the Baltic Sea area: Local Agenda 21 within the Union of the Baltic Cities network.

    Science.gov (United States)

    Joas, M; Grönholm, B

    2001-08-01

    Local Agenda 21 (LA21) processes have 2 central goals. i) On the basis of some of the empirical evidence in this study, the primary goal is to improve democratic (environmental) policy-making processes in such a manner that a larger share of the population will be able to participate in planning and decision making and will also be able to understand the consequences of these decisions. ii) The LA21 processes seek to improve (at least indirectly) the broadly defined environmental situation locally in a manner that takes into account both the local and the global contexts. The first part of this article discusses the concept and methods of LA21 and sheds light on the different action areas that are central to the Baltic LA21 processes. In addition, the study will describe and display the LA21 situation within one network of cities, the Union of the Baltic Cities (UBC). Networking, including transfer of information, models and ideas, has been among the main tools for the diffusion of LA21 ideas especially into newly democratized societies. Finally, the article will conclude with an overall assessment of the LA21 situation on the Baltic rim.

  1. The role of sediment compaction and groundwater withdrawal in local sea-level rise, Sandy Hook, New Jersey, USA

    Science.gov (United States)

    Johnson, Christopher S.; Miller, Kenneth G.; Browning, James V.; Kopp, Robert E.; Khan, Nicole S.; Fan, Ying; Stanford, Scott D.; Horton, Benjamin P.

    2018-02-01

    The rate of relative sea-level (RSL) rise at Sandy Hook, NJ (4.0 ± 0.5 mm/yr) was higher than The Battery, NY (3.0 ± 0.3 mm/yr) from 1900 to 2012 despite being separated by just 26 km. The difference cannot be explained by differential glacial isostatic adjustment (GIA; 1.4 ± 0.4 and 1.3 ± 0.4 mm/yr RSL rise, respectively) alone. We estimate the contribution of sediment compaction to subsidence at Sandy Hook using high-resolution grain size, percent organic matter, and porosity data from three upper Quaternary (≤13,350 cal yr) cores. The organic matter content (indicates that compaction of deglacial silts likely reduced the column thickness by 10-20% over the past 13,350 cal yrs. While compaction rates were high immediately after the main silt deposition (13,350-13,150 cal yrs BP), rates decreased exponentially after deposition to an average 20th century rate of 0.16 mm/yr (90% Confidence Interval (C.I.), 0.06-0.32 mm/yr). The remaining ∼0.7 mm/yr (90% C.I. 0.3-1.2 mm/yr) difference in subsidence between Sandy Hook and The Battery is likely due to anthropogenic groundwater withdrawal. Historical data from Fort Hancock wells (2 km to the southeast of the Sandy Hook tide gauge) and previous regional work show that local and regional water extraction lowered the water levels in the aquifers underlying Sandy Hook. We suggest that the modern order of contribution to subsidence (highest to lowest) appears to be GIA, local/regional groundwater extraction, and compaction of thick Quaternary silts.

  2. Changing Sea Levels

    Science.gov (United States)

    Pugh, David

    2004-04-01

    Flooding of coastal communities is one of the major causes of environmental disasters world-wide. This textbook explains how sea levels are affected by astronomical tides, weather effects, ocean circulation and climate trends. Based on courses taught by the author in the U.K. and the U.S., it is aimed at undergraduate students at all levels, with non-basic mathematics being confined to Appendices and a website http://publishing.cambridge.org/resources/0521532183/.

  3. Coastal Adaptation Planning for Sea Level Rise and Extremes: A Global Model for Adaptation Decision-making at the Local Level Given Uncertain Climate Projections

    Science.gov (United States)

    Turner, D.

    2014-12-01

    Understanding the potential economic and physical impacts of climate change on coastal resources involves evaluating a number of distinct adaptive responses. This paper presents a tool for such analysis, a spatially-disaggregated optimization model for adaptation to sea level rise (SLR) and storm surge, the Coastal Impact and Adaptation Model (CIAM). This decision-making framework fills a gap between very detailed studies of specific locations and overly aggregate global analyses. While CIAM is global in scope, the optimal adaptation strategy is determined at the local level, evaluating over 12,000 coastal segments as described in the DIVA database (Vafeidis et al. 2006). The decision to pursue a given adaptation measure depends on local socioeconomic factors like income, population, and land values and how they develop over time, relative to the magnitude of potential coastal impacts, based on geophysical attributes like inundation zones and storm surge. For example, the model's decision to protect or retreat considers the costs of constructing and maintaining coastal defenses versus those of relocating people and capital to minimize damages from land inundation and coastal storms. Uncertain storm surge events are modeled with a generalized extreme value distribution calibrated to data on local surge extremes. Adaptation is optimized for the near-term outlook, in an "act then learn then act" framework that is repeated over the model time horizon. This framework allows the adaptation strategy to be flexibly updated, reflecting the process of iterative risk management. CIAM provides new estimates of the economic costs of SLR; moreover, these detailed results can be compactly represented in a set of adaptation and damage functions for use in integrated assessment models. Alongside the optimal result, CIAM evaluates suboptimal cases and finds that global costs could increase by an order of magnitude, illustrating the importance of adaptive capacity and coastal policy.

  4. A Simple Model Framework to Explore the Deeply Uncertain, Local Sea Level Response to Climate Change. A Case Study on New Orleans, Louisiana

    Science.gov (United States)

    Bakker, Alexander; Louchard, Domitille; Keller, Klaus

    2016-04-01

    Sea-level rise threatens many coastal areas around the world. The integrated assessment of potential adaptation and mitigation strategies requires a sound understanding of the upper tails and the major drivers of the uncertainties. Global warming causes sea-level to rise, primarily due to thermal expansion of the oceans and mass loss of the major ice sheets, smaller ice caps and glaciers. These components show distinctly different responses to temperature changes with respect to response time, threshold behavior, and local fingerprints. Projections of these different components are deeply uncertain. Projected uncertainty ranges strongly depend on (necessary) pragmatic choices and assumptions; e.g. on the applied climate scenarios, which processes to include and how to parameterize them, and on error structure of the observations. Competing assumptions are very hard to objectively weigh. Hence, uncertainties of sea-level response are hard to grasp in a single distribution function. The deep uncertainty can be better understood by making clear the key assumptions. Here we demonstrate this approach using a relatively simple model framework. We present a mechanistically motivated, but simple model framework that is intended to efficiently explore the deeply uncertain sea-level response to anthropogenic climate change. The model consists of 'building blocks' that represent the major components of sea-level response and its uncertainties, including threshold behavior. The framework's simplicity enables the simulation of large ensembles allowing for an efficient exploration of parameter uncertainty and for the simulation of multiple combined adaptation and mitigation strategies. The model framework can skilfully reproduce earlier major sea level assessments, but due to the modular setup it can also be easily utilized to explore high-end scenarios and the effect of competing assumptions and parameterizations.

  5. A Late Pleistocene sea level stack

    OpenAIRE

    Spratt Rachel M; Lisiecki Lorraine E

    2016-01-01

    Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal componen...

  6. Sea Level Rise Data Discovery

    Science.gov (United States)

    Quach, N.; Huang, T.; Boening, C.; Gill, K. M.

    2016-12-01

    Research related to sea level rise crosses multiple disciplines from sea ice to land hydrology. The NASA Sea Level Change Portal (SLCP) is a one-stop source for current sea level change information and data, including interactive tools for accessing and viewing regional data, a virtual dashboard of sea level indicators, and ongoing updates through a suite of editorial products that include content articles, graphics, videos, and animations. The architecture behind the SLCP makes it possible to integrate web content and data relevant to sea level change that are archived across various data centers as well as new data generated by sea level change principal investigators. The Extensible Data Gateway Environment (EDGE) is incorporated into the SLCP architecture to provide a unified platform for web content and science data discovery. EDGE is a data integration platform designed to facilitate high-performance geospatial data discovery and access with the ability to support multi-metadata standard specifications. EDGE has the capability to retrieve data from one or more sources and package the resulting sets into a single response to the requestor. With this unified endpoint, the Data Analysis Tool that is available on the SLCP can retrieve dataset and granule level metadata as well as perform geospatial search on the data. This talk focuses on the architecture that makes it possible to seamlessly integrate and enable discovery of disparate data relevant to sea level rise.

  7. Sea level and climate variations

    NARCIS (Netherlands)

    Oerlemans, J.

    1985-01-01

    Review paper, ESA Symposium on Application of Satellite Data to Climate Modelling. Alpbach (Austria) Sea level is an essential component of the climate system, on which many human activities in the coastal zone depend. Climate variations leading to changes in relative sea level are

  8. The Barbados Sea Level Record

    Science.gov (United States)

    Fairbanks, R. G.; Mortlock, R. A.; Abdul, N. A.; Wright, J. D.; Cao, L.; Mey, J. L.

    2013-12-01

    Additional offshore drill cores, nearly 100 new radiometric dates, and more than 1000 kilometers of Multibeam mapping greatly enhance the Barbados Sea Level record. Extensive Multibeam mapping around the entire island covers approximately 2650 km2 of the sea bottom and now integrates the offshore reef topography and Barbados Sea Level Record with the unparalleled onshore core collection, digital elevation maps, and Pleistocene sea level record spanning the past one million years. The reef crest coral, Acropora palmata, remains the stalwart indicator of sea level for many reasons that are validated by our redundant sea level records and redundant dating via Th/U and Pa/U analyses. Microanalysis and densitometry studies better explain why Acropora palmata is so well preserved in the Pleistocene reef records and therefore why it is the species of choice for sea level reconstructions and radiometric dating. New drill cores into reefs that formed during Marine Isotope Stage 3 lead us to a model of diagenesis that allows us to better prospect for unaltered coral samples in older reefs that may be suitable for Th/U dating. Equally important, our diagenesis model reinforces our rigorous sample quality criteria in a more quantitative manner. The Barbados Sea Level record has a sampling resolution of better than 100 years throughout much of the last deglaciation showing unprecedented detail in redundant drill cores. The Melt Water Pulses (MWP1A and MWP1B) are well resolved and the intervening interval that includes the Younger Dryas reveals sea level changes in new detail that are consistent with the terrestrial records of ice margins (see Abdul et al., this section). More than 100 paired Th/U and radiocarbon ages place the Barbados Sea Level Record unambiguously on the radiocarbon time scale for direct comparisons with the terrestrial records of ice margin changes.

  9. The Caribbean conundrum of Holocene sea level.

    Science.gov (United States)

    Jackson, Luke; Mound, Jon

    2014-05-01

    In the tropics, pre-historic sea-level curve reconstruction is often problematic because it relies upon sea-level indicators whose vertical relationship to the sea surface is poorly constrained. In the Caribbean, fossil corals, mangrove peats and shell material dominate the pre-historic indicator record. The common approach to reconstruction involves the use of modern analogues to these indicators to establish a fixed vertical habitable range. The aim of these reconstructions is to find spatial variability in the Holocene sea level in an area gradually subsiding (different depths. We use the first catalogue to calibrate 14C ages to give a probabilistic age range for each indicator. We use the second catalogue to define a depth probability distribution function (pdf) for mangroves and each coral species. The Holocene indicators are grouped into 12 sub-regions around the Caribbean. For each sub-region we apply our sea-level reconstruction, which involves stepping a fixed-length time window through time and calculating the position (and rate) of sea-level (change) using a thousand realisations of the time/depth pdfs to define an envelope of probable solutions. We find that the sub-regional relative sea-level curves display spatio-temporal variability including a south-east to north-west 1500 year lag in the arrival of Holocene sea level to that of the present day. We demonstrate that these variations are primarily due to glacial-isostatic-adjustment induced sea-level change and that sub-regional variations (where sufficient data exists) are due to local uplift variability.

  10. Intermittent sea-level acceleration

    Science.gov (United States)

    Olivieri, M.; Spada, G.

    2013-10-01

    Using instrumental observations from the Permanent Service for Mean Sea Level (PSMSL), we provide a new assessment of the global sea-level acceleration for the last ~ 2 centuries (1820-2010). Our results, obtained by a stack of tide gauge time series, confirm the existence of a global sea-level acceleration (GSLA) and, coherently with independent assessments so far, they point to a value close to 0.01 mm/yr2. However, differently from previous studies, we discuss how change points or abrupt inflections in individual sea-level time series have contributed to the GSLA. Our analysis, based on methods borrowed from econometrics, suggests the existence of two distinct driving mechanisms for the GSLA, both involving a minority of tide gauges globally. The first effectively implies a gradual increase in the rate of sea-level rise at individual tide gauges, while the second is manifest through a sequence of catastrophic variations of the sea-level trend. These occurred intermittently since the end of the 19th century and became more frequent during the last four decades.

  11. Is sea-level rising?

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    correction in the estimation of trends obtained for tide gauge records. The altimeter data permits to prepare spatial maps of sea-level rise trends. We present a map prepared for the Indian Ocean (Figure 4) north of 10oS , which shows a fairly uniform... drawn information from research papers published by the author and report of the IPCC AR5 WG1 Chapter 13: Sea Level Changes, in which the author has served as a ‘Lead Author’. Figure1 is prepared using data from the University of Colorado. Nerem, R...

  12. Recent Arctic Sea Level Variations from Satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Piccioni, Gaia

    2016-01-01

    Sea level monitoring in the Arctic region has always been an extreme challenge for remote sensing, and in particular for satellite altimetry. Despite more than two decades of observations, altimetry is still limited in the inner Arctic Ocean. We have developed an updated version of the Danish...... Technical University's (DTU) Arctic Ocean altimetric sea level timeseries starting in 1993 and now extended up to 2015 with CryoSat-2 data. The time-series covers a total of 23 years, which allows higher accuracy in sea level trend determination. The record shows a sea level trend of 2.2 ± 1.1 mm....../y for the region between 66°N and 82°N. In particular, a local increase of 15 mm/y is found in correspondence to the Beaufort Gyre. An early estimate of the mean sea level trend budget closure in the Arctic for the period 2005–2015 was derived by using the Equivalent Water Heights obtained from GRACE Tellus...

  13. Advancing Best Practices for the Formulation of Localized Sea Level Rise/Coastal Inundation Extremes Scenarios for Military Installations in the Pacific Islands

    Science.gov (United States)

    2015-07-14

    in mean sea level, El Niño Southern Oscillation (ENSO) and other modes of natural variability, tropical and extratropical storms , and unusually high...parameter) and changes in typical ( extratropical ) storm track (scale parameter) need to be explored as does the applicability of customized climate...mean sea level over decades to months; tropical and extratropical storms , and swell from distant storms that manifest as events lasting hours to

  14. Eustatic and Relative Sea Level Changes

    NARCIS (Netherlands)

    Rovere, A.; Stocchi, P.; Vacchi, M.

    2016-01-01

    Sea level changes can be driven by either variationsin the masses or volume of the oceans, or bychanges of the land with respect to the sea surface. Inthe first case, a sea level change is defined ‘eustatic’;otherwise, it is defined ‘relative’. Several techniques canbe used to observe changes in sea

  15. Local diffusion coefficient determination: Mediterranean Sea experiments

    International Nuclear Information System (INIS)

    Bacciola, D.; Borghini, M.; Cannarsa, S.

    1993-10-01

    The Mediterranean is a semi/enclosed basin characterized by the presence of channels and straits influencing the circulation, temperature and salinity fields. The tides generally have amplitudes of the order of 10 cm and velocities of few cm/s. Conversely, the wind forced circulation is very strong and can assume velocity values of 1 m/s at the sea surface. The temperature and salinity fields have a high temporal and spatial variability, because of many mixing processes existing in the sea. For example, the waters coming from the Provencal basin meet those waters coming from the Tyrrhenian Sea in the eastern Ligurian Sea, creating meanders and eddies. Local runoff influences significantly the coastal circulation. This paper describes diffusion experiments carried out in this complex environment. The experimental apparatus for the detection of the fluorescine released at sea was composed by two Turner mod. 450 fluorometres. During the experiments, temperature and salinity vertical profiles were measured by using a CTD; meteorological data were acquired on a dinghy. The positioning was obtained by means of a Motorola system, having a precision of about 1 meter. The experiments were carried out under different stratification and wind conditions. From data analysis it was found that the horizontal diffusion coefficient does not depend on time or boundary conditions. The role of stratification is important with regard to vertical displacement of the dye. However, its role with regard to vertical diffusion cannot be assessed with the actual experimental apparatus

  16. Analysis of Sea Level Rise in Singapore Strait

    Science.gov (United States)

    Tkalich, Pavel; Luu, Quang-Hung

    2013-04-01

    Sea level in Singapore Strait is governed by various scale phenomena, from global to local. Global signals are dominated by the climate change and multi-decadal variability and associated sea level rise; at regional scale seasonal sea level variability is caused by ENSO-modulated monsoons; locally, astronomic tides are the strongest force. Tide gauge records in Singapore Strait are analyzed to derive local sea level trend, and attempts are made to attribute observed sea level variability to phenomena at various scales, from global to local. It is found that at annual scale, sea level anomalies in Singapore Strait are quasi-periodic, of the order of ±15 cm, the highest during northeast monsoon and the lowest during southwest monsoon. Interannual regional sea level falls are associated with El Niño events, while the rises are related to La Niña episodes; both variations are in the range of ±9 cm. At multi-decadal scale, sea level in Singapore Strait has been rising at the rate 1.2-1.9 mm/year for the period 1975-2009, 2.0±0.3 mm/year for 1984-2009, and 1.3-4.7 mm/year for 1993-2009. When compared with the respective global trends of 2.0±0.3, 2.4, and 2.8±0.8 mm/year, Singapore Strait sea level rise trend was weaker at the earlier period and stronger at the recent decade.

  17. The impact of local land subsidence and global sea level rise on flood severity in Houston-Galveston caused by Hurricane Harvey

    Science.gov (United States)

    Miller, M. M.; Shirzaei, M.

    2017-12-01

    Category-4 Hurricane Harvey had devastating socioeconomic impacts to Houston, with flooding far past the 100-year flood zones published by FEMA. In recent decades, frequency and intensity of coastal flooding are escalating, correlated with sea level rise (SLR). Moreover, Local land subsidence (LLS) due to groundwater and hydrocarbon extraction and natural compaction changes surface elevation and slope, potentially altering drainage patterns. GPS data show a mm broad co-cyclonic subsidence due to elastic loading from the water mass measured by GPS, which is inverted to solve for the total fluid volume of 2.73x1010 m3. We additionally investigate the joint impact of an SLR and pre-cyclonic LLS on the flooding of Houston-Galveston during Hurricane Harvey. We examine vertical land motion within North American Vertical Datum 2012 for the period 2007 until the cyclone by investigating SAR imaged acquired by ALOS and Sentinel-1A/B radar satellites combined with GPS data. We find patchy, LLS bowls resulting in sinks where floodwater can collect. We map the flooding extent by comparing amplitudes of Sentinal1-A/B pixels' backscattered radar signal from pre- and post-Harvey acquisitions and estimate 782 km2 are submerged within the area of 3478 km2 of pixels covered by Sentinel frame. Comparing with the LLS map, 89% of the flooded pixels exhibit -3 mm/yr or greater vertical motion. Flooding attributed to the storm surge is determined with high-resolution LiDAR digital elevation models (DEM) and a 0.75 m storm tide inundation model, which engulfs only 195 km2 and nearby the shorelines. We estimate future inundation hazard by combining LiDAR DEMs with our InSAR derived subsidence map, projecting LLS rates forward 100 years, and modeling projected SLR from 0.4 to 1.2 meters. Were subsidence to continue unabated, the total flooded area is 281 km2 with a 0.4 m and 394 km2 with a 1.2 m SLR. Next, we add a modest storm tide (0.752 m), which increases the flooded area to 389 - 480

  18. Assessing Flood Risk Under Sea Level Rise and Extreme Sea Levels Scenarios: Application to the Ebro Delta (Spain)

    Science.gov (United States)

    Sayol, J. M.; Marcos, M.

    2018-02-01

    This study presents a novel methodology to estimate the impact of local sea level rise and extreme surges and waves in coastal areas under climate change scenarios. The methodology is applied to the Ebro Delta, a valuable and vulnerable low-lying wetland located in the northwestern Mediterranean Sea. Projections of local sea level accounting for all contributions to mean sea level changes, including thermal expansion, dynamic changes, fresh water addition and glacial isostatic adjustment, have been obtained from regionalized sea level projections during the 21st century. Particular attention has been paid to the uncertainties, which have been derived from the spread of the multi-model ensemble combined with seasonal/inter-annual sea level variability from local tide gauge observations. Besides vertical land movements have also been integrated to estimate local relative sea level rise. On the other hand, regional projections over the Mediterranean basin of storm surges and wind-waves have been used to evaluate changes in extreme events. The compound effects of surges and extreme waves have been quantified using their joint probability distributions. Finally, offshore sea level projections from extreme events superimposed to mean sea level have been propagated onto a high resolution digital elevation model of the study region in order to construct flood hazards maps for mid and end of the 21st century and under two different climate change scenarios. The effect of each contribution has been evaluated in terms of percentage of the area exposed to coastal hazards, which will help to design more efficient protection and adaptation measures.

  19. Future extreme sea level seesaws in the tropical Pacific.

    Science.gov (United States)

    Widlansky, Matthew J; Timmermann, Axel; Cai, Wenju

    2015-09-01

    Global mean sea levels are projected to gradually rise in response to greenhouse warming. However, on shorter time scales, modes of natural climate variability in the Pacific, such as the El Niño-Southern Oscillation (ENSO), can affect regional sea level variability and extremes, with considerable impacts on coastal ecosystems and island nations. How these shorter-term sea level fluctuations will change in association with a projected increase in extreme El Niño and its atmospheric variability remains unknown. Using present-generation coupled climate models forced with increasing greenhouse gas concentrations and subtracting the effect of global mean sea level rise, we find that climate change will enhance El Niño-related sea level extremes, especially in the tropical southwestern Pacific, where very low sea level events, locally known as Taimasa, are projected to double in occurrence. Additionally, and throughout the tropical Pacific, prolonged interannual sea level inundations are also found to become more likely with greenhouse warming and increased frequency of extreme La Niña events, thus exacerbating the coastal impacts of the projected global mean sea level rise.

  20. An Integrated Framework to Analyze Local Decision Making and Adaptation to Sea-Level Rise in Coastal Regions in Santos-Brazil, Broward County-USA and Selsey-UK

    Science.gov (United States)

    Marengo, J. A.; Muller-Karger, F. E.; Pelling, M.; Reynolds, C. J.; Merril, S. B.; Nunes, L. H.; Paterson, S.; Gray, A.; Lockman, J. T.; Kartez, J.; Moreira, F.; Greco, R.; Harari, J.; Souza, C. G.; Alves, L. M.; Hosokawa, E.; Tabuchi, E.

    2016-12-01

    One of the clear signals of present climate change is sea level rise (SLR). There is mounting evidence of other changes, including warmer temperatures in many localities, and changes in the intensity and frequency of extreme meteorological events, including wind, rain, and waves. A rising sea level combined with these factors and tides is expected to affect coastal communities through a number of processes, including increased risk of flooding and contamination of water sources. An international collaboration between Brazil, the United Kingdom, and the United States was designed to evaluate local decision making processes and to open convening space for local urban managers to reflect on possible actions toward adaption to SLR and the constraints imposed by framing administrative and institutional structures. The overall goal of the project is to help coastal communities better understand factors that facilitate or hinder their intrinsic, local decision-making processes related to planning for adaptation to risk. The project carried out these tests in 2014 and 2015 in one coastal city in each partnering nation. The framework was designed by an interdisciplinary team that incorporated social and natural scientists from these three nations, and which included local government officials. To support the overall goal, this paper 1) discusses some aspects of adaptive capacity and participant survey research conducted through the project, 2) presents technical modelling results for adaptation options that may reduce the potential damages of SLR and storm surge in each location, and 3) identifies project design considerations for similar transnational adaptation projects.

  1. Coastal Sea Levels, Impacts, and Adaptation

    Directory of Open Access Journals (Sweden)

    Thomas Wahl

    2018-02-01

    Full Text Available Sea-level rise (SLR poses a great threat to approximately 10% of the world’s population residing in low-elevation coastal zones (i.e., land located up to 10 m of present-day mean sea-level (MSL[...

  2. Causes for contemporary regional sea level changes.

    Science.gov (United States)

    Stammer, Detlef; Cazenave, Anny; Ponte, Rui M; Tamisiea, Mark E

    2013-01-01

    Regional sea level changes can deviate substantially from those of the global mean, can vary on a broad range of timescales, and in some regions can even lead to a reversal of long-term global mean sea level trends. The underlying causes are associated with dynamic variations in the ocean circulation as part of climate modes of variability and with an isostatic adjustment of Earth's crust to past and ongoing changes in polar ice masses and continental water storage. Relative to the coastline, sea level is also affected by processes such as earthquakes and anthropogenically induced subsidence. Present-day regional sea level changes appear to be caused primarily by natural climate variability. However, the imprint of anthropogenic effects on regional sea level-whether due to changes in the atmospheric forcing or to mass variations in the system-will grow with time as climate change progresses, and toward the end of the twenty-first century, regional sea level patterns will be a superposition of climate variability modes and natural and anthropogenically induced static sea level patterns. Attribution and predictions of ongoing and future sea level changes require an expanded and sustained climate observing system.

  3. Sea level rise : A literature survey

    NARCIS (Netherlands)

    Oude Essink, G.H.P.

    1992-01-01

    In order to assess the impact of sea level rise on Water Management, it is useful to understand the mechanisrns that determine the level of the sea. In this study, a literature survey is executed to analyze these mechanisms. Climate plays a centra! role in these mechanisms, Climate mainly changes

  4. Greenhouse warming and changes in sea level

    NARCIS (Netherlands)

    Oerlemans, J.

    1989-01-01

    It is likely that the anticipated warming due to the effect of increasing concentration of carbon dioxide and other greenhouse gases will lead to a further and faster rise in world mean sea level. There are many processes in the climate system controlling sea level, but the most important

  5. Sea Level Changes: Determination and Effects

    Science.gov (United States)

    Woodworth, P. L.; Pugh, D. T.; DeRonde, J. G.; Warrick, R. G.; Hannah, J.

    The measurement of sea level is of fundamental importance to a wide range of research in climatology, oceanography, geology and geodesy. This volume attempts to cover many aspects of the field. The volume opens with a description by Bolduc and Murty of one of the products stemming from the development of tide gauge networks in the northern and tropical Atlantic. This work is relevant to the growth of the Global Sea Level Observing System (GLOSS), the main goal of which is to provide the world with an efficient, coherent sea level monitoring system for océanographie and climatological research. The subsequent four papers present results from the analysis of existing tide gauge data, including those datasets available from the Permanent Service for Mean Sea Level and the TOGA Sea Level Center. Two of the four, by Wroblewski and by Pasaric and Orlic, are concerned with European sea level changes, while Yu Jiye et al. discuss inter-annual changes in the Pacific, and Wang Baocan et al. describe variability in the Changjiang estuary in China. The papers by El- Abd and A wad, on Red Sea levels, are the only contributions to the volume from the large research community of geologists concerned with sea level changes.

  6. Global change and the measurement of absolute sea-level

    Science.gov (United States)

    Diamante, John M.; Pyle, Thomas E.; Carter, William E.; Scherer, Wolfgang

    To quantify properly the long-term response of sea-level to climate change, land motions must be separated from the apparent or relative sea-level change recorded by conventional tide/sea-level gauges. Here we present a concept for global measurement of the true or “absolute” sea-level change, which combines recent advances in space-based geodetic techniques with plans for a global sea-level network under the World Climate Research Programme (WCRP). Data from initial feasibility tests show that land motion, due to global (plate tectonic), regional (glacial rebound), or local (fluid withdrawal) effects, can probably be measured to ±1cm (on a single measurement basis) by an innovative combination of Very Long Baseline Interferometry (VLBI) and Global Positioning System (GPS) tevhniques. By making repeated observations of position at a number of tide gauges using portable, economical GPS receivers in a differential mode relative to the fewer, more stable, but more expensive VLBI observatories, it will be possible to subtract land motion from the relative sea-level signal. Decadal to century scale trends at the 1-2mm y -1 level will be resolvable in the sea-level and vertical land motion time series within about a decade. Detection of subsidence or uplift at specific gauges will allow correction for land motion or deletion of bad data when computing regional or global, i.e. eustatic, sea-level changes. In addition to their applications in oceanography and climate studies, such data will test models by Peltier and other that relate mantle viscosity and deglaciation history to present rates of crustal subsidence or uplift. If the predicted crustal motions are confirmed, we can also have more confidence in the use of historical tide/sea-level gauge records in retrospective studies of sea-level change related to climate variability on decadal or longer time scales. It is concluded that as few as one-third (about 100) of the total number of tide/sea-level gauges (250

  7. Sea level rise in the Arctic Ocean

    OpenAIRE

    Proshutinsky, Andrey; Pavlov, Vladimir; Bourke, Robert H.

    2001-01-01

    The article of record as published may be found at http://dx.doi.org/10.1029/2000GL012760 About 60 tide-gauge stations in the Kara, Laptev, East-Siberian and Chukchi Seas have recorded the sea level change from the 1950s through 1990s. Over this 40-year period, most of these stations show a significant sea level rise (SLR). In light of global change, this SLR could be a manifestation of warming in the Artic coupled with a decrease of sea ice extent, warming of Atlantic waters, changes in...

  8. Global mapping of nonseismic sea level oscillations at tsunami timescales.

    Science.gov (United States)

    Vilibić, Ivica; Šepić, Jadranka

    2017-01-18

    Present investigations of sea level extremes are based on hourly data measured at coastal tide gauges. The use of hourly data restricts existing global and regional analyses to periods larger than 2 h. However, a number of processes occur at minute timescales, of which the most ruinous are tsunamis. Meteotsunamis, hazardous nonseismic waves that occur at tsunami timescales over limited regions, may also locally dominate sea level extremes. Here, we show that nonseismic sea level oscillations at tsunami timescales (sea level extremes, up to 50% in low-tidal basins. The intensity of these oscillations is zonally correlated with mid-tropospheric winds at the 99% significance level, with the variance doubling from the tropics and subtropics to the mid-latitudes. Specific atmospheric patterns are found during strong events at selected locations in the World Ocean, indicating a globally predominant generation mechanism. Our analysis suggests that these oscillations should be considered in sea level hazard assessment studies. Establishing a strong correlation between nonseismic sea level oscillations at tsunami timescales and atmospheric synoptic patterns would allow for forecasting of nonseismic sea level oscillations for operational use, as well as hindcasting and projection of their effects under past, present and future climates.

  9. The Influence of Wind and Basin Eddies in Controlling Sea Level Variations in the Coastal Red Sea

    KAUST Repository

    Abualnaja, Yasser

    2015-04-01

    Sea level variations in the central Red Sea coastal zone span a range of roughly 1.2 m. Though relatively small, these water level changes can significantly impact the environment over the shallow reef tops prevalent in the central Red Sea, altering the water depth by a factor or two or more. Roughly half of the coastal sea level variance in central Red Sea is due to elevation changes in an \\'intermediate\\' frequency band, with periods between 2 days and 1 month. We examined the sea level signal in this band using the data from pressure sensors maintained for more than five years at a number of locations in Saudi Arabian coastal waters between 20.1 and 23.5 oN. We find that the intermediate-band sea level variations are strongly correlated with the local wind stress measured at a meteorological buoy. The maximum pressure-wind correlation occurs at wind direction closely aligned with the alongshore orientation and at a lag (wind leading) of 45 hr, which is consistent with the expected response of the coastal sea level to local wind forcing. However, less than half of the sea level variance in the intermediate band is related, through linear correlation, with local wind forcing. Our analysis indicates that the residual coastal sea level signal, not associated with wind forcing, is largely driven remotely by the passage of mesoscale eddies, revealed by satellite altimeter-derived sea level anomaly fields of the central Red Sea. These eddy-driven coastal sea level changes occur on time scales of 10-30 days. They span a range of 0.5 m, and thus constitute an import component of the sea level signal in the coastal Red Sea.

  10. The Influence of Wind and Basin Eddies in Controlling Sea Level Variations in the Coastal Red Sea

    KAUST Repository

    Abualnaja, Yasser; Churchill, James H.; Nellayaputhenpeedika, Mohammedali; Limeburner, Richard

    2015-01-01

    Sea level variations in the central Red Sea coastal zone span a range of roughly 1.2 m. Though relatively small, these water level changes can significantly impact the environment over the shallow reef tops prevalent in the central Red Sea, altering the water depth by a factor or two or more. Roughly half of the coastal sea level variance in central Red Sea is due to elevation changes in an 'intermediate' frequency band, with periods between 2 days and 1 month. We examined the sea level signal in this band using the data from pressure sensors maintained for more than five years at a number of locations in Saudi Arabian coastal waters between 20.1 and 23.5 oN. We find that the intermediate-band sea level variations are strongly correlated with the local wind stress measured at a meteorological buoy. The maximum pressure-wind correlation occurs at wind direction closely aligned with the alongshore orientation and at a lag (wind leading) of 45 hr, which is consistent with the expected response of the coastal sea level to local wind forcing. However, less than half of the sea level variance in the intermediate band is related, through linear correlation, with local wind forcing. Our analysis indicates that the residual coastal sea level signal, not associated with wind forcing, is largely driven remotely by the passage of mesoscale eddies, revealed by satellite altimeter-derived sea level anomaly fields of the central Red Sea. These eddy-driven coastal sea level changes occur on time scales of 10-30 days. They span a range of 0.5 m, and thus constitute an import component of the sea level signal in the coastal Red Sea.

  11. Coupling of sea level and tidal range changes, with implications for future water levels.

    Science.gov (United States)

    Devlin, Adam T; Jay, David A; Talke, Stefan A; Zaron, Edward D; Pan, Jiayi; Lin, Hui

    2017-12-05

    Are perturbations to ocean tides correlated with changing sea-level and climate, and how will this affect high water levels? Here, we survey 152 tide gauges in the Pacific Ocean and South China Sea and statistically evaluate how the sum of the four largest tidal constituents, a proxy for the highest astronomical tide (HAT), changes over seasonal and interannual time scales. We find that the variability in HAT is significantly correlated with sea-level variability; approximately 35% of stations exhibit a greater than ±50 mm tidal change per meter sea-level fluctuation. Focusing on a subset of three stations with long records, probability density function (PDF) analyses of the 95% percentile exceedance of total sea level (TSL) show long-term changes of this high-water metric. At Hong Kong, the increase in tides significantly amplifies the risk caused by sea-level rise. Regions of tidal decrease and/or amplification highlight the non-linear response to sea-level variations, with the potential to amplify or mitigate against the increased flood risk caused by sea-level rise. Overall, our analysis suggests that in many regions, local flood level determinations should consider the joint effects of non-stationary tides and mean sea level (MSL) at multiple time scales.

  12. Regional sea level projections with observed gauge, altimeter and reconstructed data along China coast

    Science.gov (United States)

    Du, L.; Shi, H.; Zhang, S.

    2017-12-01

    Acting as the typical shelf seas in northwest Pacific Ocean, regional sea level along China coasts exhibits complicated and multiscale spatial-temporal characteristics under circumstance of global change. In this paper, sea level variability is investigated with tide gauges records, satellite altimetry data, reconstructed sea surface height, and CMIP simulation fields. Sea level exhibits the interannual variability imposing on a remarkable sea level rising in the China seas and coastal region, although its seasonal signals are significant as the results of global ocean. Sea level exhibits faster rising rate during the satellite altimetry era, nearly twice to the rate during the last sixty years. AVISO data and reconstructed sea surface heights illustrate good correlation coefficient, more than 0.8. Interannual sea level variation is mainly modulated by the low-frequency variability of wind fields over northern Pacific Ocean by local and remote processes. Meanwhile sea level varies obviously by the transport fluctuation and bimodality path of Kuroshio. Its variability possibly linked to internal variability of the ocean-atmosphere system influenced by ENSO oscillation. China Sea level have been rising during the 20th century, and are projected to continue to rise during this century. Sea level can reach the highest extreme level in latter half of 21st century. Modeled sea level including regional sea level projection combined with the IPCC climate scenarios play a significant role on coastal storm surge evolution. The vulnerable regions along the ECS coast will suffer from the increasing storm damage with sea level variations.

  13. Sea-level changes on multiple spatial scales: estimates and contributing processes

    NARCIS (Netherlands)

    Frederikse, T.

    2018-01-01

    Being one of the major consequences of anthropogenic climate change, sea level rise forms a threat for many coastal areas and their inhabitants. Because all processes that cause sea-level changes have a spatially-varying fingerprint, local sea-level changes deviate substantially from the global

  14. Generalized Cauchy model of sea level fluctuations with long-range dependence

    Science.gov (United States)

    Li, Ming; Li, Jia-Yue

    2017-10-01

    This article suggests the contributions with two highlights. One is to propose a novel model of sea level fluctuations (sea level for short), which is called the generalized Cauchy (GC) process. It provides a new outlook for the description of local and global behaviors of sea level from a view of fractal in that the fractal dimension D that measures the local behavior of sea level and the Hurst parameter H which characterizes the global behavior of sea level are independent of each other. The other is to show that sea level appears multi-fractal in both spatial and time. Such a meaning of multi-fractal is new in the sense that a pair of fractal parameters (D, H) of sea level is varying with measurement sites and time. This research exhibits that the ranges of D and H of sea level, in general, are 1 ≤ D sea level, we shall show that H > 0 . 96 for all data records at all measurement sites, implying that strong LRD may be a general phenomenon of sea level. On the other side, regarding with the local behavior, we will reveal that there appears D = 1 or D ≈ 1 for data records at a few stations and at some time, but D > 0 . 96 at most stations and at most time, meaning that sea level may appear highly local irregularity more frequently than weak local one.

  15. Climate Adaptation and Sea Level Rise

    Science.gov (United States)

    EPA supports the development and maintenance of water utility infrastructure across the country. Included in this effort is helping the nation’s water utilities anticipate, plan for, and adapt to risks from flooding, sea level rise, and storm surge.

  16. Millennial, centennial and decadal sea- level change in Florida, USA

    Science.gov (United States)

    Kemp, A.; Hawkes, A. D.; Donnelly, J. P.; Horton, B. P.

    2012-12-01

    Reconstructions of relative sea-level changes on millennial timescales provide data against which to test and calibrate Earth-Ice models. On the U.S. mid-Atlantic coast they constrain the geometry of the Laurentide Ice Sheet's collapsing forebulge. Sea -level data from southeastern Atlantic coast additionally constrain ice-equivalent meltwater input. Here we produce the first Holocene sea-level curve for Florida and Georgia from the St. Mary's River using agglutinated foraminifera preserved in radiocarbon-dated brackish and salt-marsh sediment. The use of foraminfera as sea-level indicators was underpinned by local and regional datasets describing the modern distribution of assemblages that are analogues for those preserved in buried sediment. This approach produced 25 index points that record 5.2 m of relative sea level rise over the last 8000 years with no evidence of a mid Holocene high stand. These reconstructions indicate that existing GIA models do not replicate proxy reconstructions and that northern Florida is subsiding in response to ongoing forebulge collapse at an estimated rate of approximately 0.3 mm/yr. Over multi decadal time scales, detailed sea level reconstructions provide an appropriate geological context for modern rates of sea-level rise. Reconstructions spanning the last 2000 years of known climate variability are important for developing models with predictive capacity that link climate and sea level changes. A reconstruction of sea-level changes since 2000 years BP was developed using a core of brackish marsh sediment from the Nassau River in Florida. Foraminifera estimated the elevation of former sea level with an uncertainty of ± 10 cm. Consistent downcore assemblages indicate that the marsh maintained its tidal elevation for 2000 years. An age depth model was developed for the core results from radiocarbon dating, 210Pb and 137Cs. The resulting relative sea level record was adjusted for the contribution made by glacio

  17. Sea level ~400 000 years ago (MIS 11: analogue for present and future sea-level?

    Directory of Open Access Journals (Sweden)

    D. Q. Bowen

    2010-01-01

    Full Text Available Comparison of the sea-level today with that of 400 000 years ago (MIS 11, when the Earth's orbital characteristics were similar may provide, under conditions of natural variability, indications of future sea-level during the present interglacial. Then, as now, orbital eccentricity was low and precession dampened. Evidence for MIS 11 sea-level occurs on uplifting coastlines where shorelines with geochronological ages have been preserved. The sea-level term and the uplift term may be separated with an "uplift correction" formula. This discovers the original sea-level at which the now uplifted shoreline was fashioned. Estimates are based on average uplift rates of the "last interglacial" sea-level (MIS 5.5 using a range of estimates for sea-level and age at that time at different locations. These, with varying secular tectonic regimes in different ocean basins, provide a band of estimates for the MIS 11 sea-level. They do not support the hypothesis of an MIS 11 sea-level at ~20 m, and instead show that it was closer to its present level.

  18. Vulnerability of marginal seas to sea level rise

    Science.gov (United States)

    Gomis, Damia; Jordà, Gabriel

    2017-04-01

    Sea level rise (SLR) is a serious thread for coastal areas and has a potential negative impact on society and economy. SLR can lead for instance to land loss, beach reduction, increase of the damage of marine storms on coastal infrastructures and to the salinization of underground water streams. It is well acknowledged that future SLR will be inhomogeneous across the globe, with regional differences of up to 100% with respect to global mean sea level (GMSL). Several studies have addressed the projections of SLR at regional scale, but most of them are based on global climate models (GCMs) that have a relatively coarse spatial resolution (>1°). In marginal seas this has proven to be a strong limitation, as their particular configurations require spatial resolutions that are not reachable by present GCMs. A paradigmatic case is the Mediterranean Sea, connected to the global ocean through the Strait of Gibraltar, a narrow passage of 14 km width. The functioning of the Mediterranean Sea involves a variety of processes including an overturning circulation, small-scale convection and a rich mesoscale field. Moreover, the long-term evolution of Mediterranean sea level has been significantly different from the global mean during the last decades. The observations of present climate and the projections for the next decades have lead some authors to hypothesize that the particular characteristics of the basin could allow Mediterranean mean sea level to evolve differently from the global mean. Assessing this point is essential to undertake proper adaptation strategies for the largely populated Mediterranean coastal areas. In this work we apply a new approach that combines regional and global projections to analyse future SLR. In a first step we focus on the quantification of the expected departures of future Mediterranean sea level from GMSL evolution and on the contribution of different processes to these departures. As a result we find that, in spite of its particularities

  19. Climate And Sea Level: It's In Our Hands Now

    Science.gov (United States)

    Turrin, M.; Bell, R. E.; Ryan, W. B. F.

    2014-12-01

    Changes in sea level are measurable on both a local and a global scale providing an accessible way to connect climate to education, yet engaging teachers and students with the complex science that is behind the change in sea level can be a challenge. Deciding how much should be included and just how it should be introduced in any single classroom subject area can be an obstacle for a teacher. The Sea Level Rise Polar Explorer App developed through the PoLAR CCEP grant offers a guided tour through the many layers of science that impact sea level rise. This map-based data-rich app is framed around a series of questions that move the user through map layers with just the level of complexity they chose to explore. For a quick look teachers and students can review a 3 or 4 sentence introduction on how the given map links to sea level and then launch straight into the interactive touchable map. For a little more in depth look they can listen to (or read) a one-minute recorded background on the data displayed in the map prior to launching in. For those who want more in depth understanding they can click to a one page background piece on the topic with links to further visualizations, videos and data. Regardless of the level of complexity selected each map is composed of clickable data allowing the user to fully explore the science. The different options for diving in allow teachers to differentiate the learning for either the subject being taught or the user level of the student group. The map layers also include a range of complexities. Basic questions like "What is sea level?" talk about shorelines, past sea levels and elevations beneath the sea. Questions like "Why does sea level change?" includes slightly more complex issues like the role of ocean temperature, and how that differs from ocean heat content. And what is the role of the warming atmosphere in sea level change? Questions about "What about sea level in the past?" can bring challenges for students who have

  20. Building more effective sea level rise models for coastal management

    Science.gov (United States)

    Kidwell, D.; Buckel, C.; Collini, R.; Meckley, T.

    2017-12-01

    For over a decade, increased attention on coastal resilience and adaptation to sea level rise has resulted in a proliferation of predictive models and tools. This proliferation has enhanced our understanding of our vulnerability to sea level rise, but has also led to stakeholder fatigue in trying to realize the value of each advancement. These models vary in type and complexity ranging from GIS-based bathtub viewers to modeling systems that dynamically couple complex biophysical and geomorphic processes. These approaches and capabilities typically have the common purpose using scenarios of global and regional sea level change to inform adaptation and mitigation. In addition, stakeholders are often presented a plethora of options to address sea level rise issues from a variety of agencies, academics, and consulting firms. All of this can result in confusion, misapplication of a specific model/tool, and stakeholder feedback of "no more new science or tools, just help me understand which one to use". Concerns from stakeholders have led to the question; how do we move forward with sea level rise modeling? This presentation will provide a synthesis of the experiences and feedback derived from NOAA's Ecological Effects of Sea level Rise (EESLR) program to discuss the future of predictive sea level rise impact modeling. EESLR is an applied research program focused on the advancement of dynamic modeling capabilities in collaboration with local and regional stakeholders. Key concerns from stakeholder engagement include questions about model uncertainty, approaches for model validation, and a lack of cross-model comparisons. Effective communication of model/tool products, capabilities, and results is paramount to address these concerns. Looking forward, the most effective predictions of sea level rise impacts on our coast will be attained through a focus on coupled modeling systems, particularly those that connect natural processes and human response.

  1. Upper Limit for Regional Sea Level Projections

    Science.gov (United States)

    Jevrejeva, Svetlana; Jackson, Luke; Riva, Riccardo; Grinsted, Aslak; Moore, John

    2016-04-01

    With more than 150 million people living within 1 m of high tide future sea level rise is one of the most damaging aspects of warming climate. The latest Intergovernmental Panel on Climate Change report (AR5 IPCC) noted that a 0.5 m rise in mean sea level will result in a dramatic increase the frequency of high water extremes - by an order of magnitude, or more in some regions. Thus the flood threat to the rapidly growing urban populations and associated infrastructure in coastal areas are major concerns for society. Hence, impact assessment, risk management, adaptation strategy and long-term decision making in coastal areas depend on projections of mean sea level and crucially its low probability, high impact, upper range. With probabilistic approach we produce regional sea level projections taking into account large uncertainties associated with Greenland and Antarctica ice sheets contribution. We calculate the upper limit (as 95%) for regional sea level projections by 2100 with RCP8.5 scenario, suggesting that for the most coastlines upper limit will exceed the global upper limit of 1.8 m.

  2. Coral seas in fifty years: Need for local policies

    Science.gov (United States)

    Longley, P.; Cheng, N. S.; Fontaine, R. M.; Horton, K.; Bhattacharya, A.

    2017-12-01

    Arising stressors from both global and local sources threaten coral reefs, with studies indicating that local and global sources might reduce coral resilience. Local sources include sediment stress and nutrient stress from fishing; global sources include increasing sea surface temperature and ocean acidification. Through an in-depth review and re-analysis of published work, conducted under the scope of a course in the spring of 2017 semester and follow up research over the summer of 2017 and fall of 2017, students in Environmental Studies Course, ENVS 4100: Coral reefs, at the University of Colorado Boulder have developed a framework to initiate a discussion of global and local policies focused on protection of coral reefs. The research aims to assess current threats and suggest mitigation efforts. The paper uses secondary research to analyze impact of ocean acidification on aragonite saturation levels, current thermal stress, nutrient stress, and sediment factors that influence the health of coral and its surrounding ecosystem over the Common Era. Case studies in this paper include the Caribbean and Red Sea coral reefs, due to the variation of the atmosphere, temperature, and human activity in these regions. This paper intends to offer sufficient evidence that will lead to appropriate policy decisions that pertain to reef conservation.

  3. Rising sea levels and small island states

    International Nuclear Information System (INIS)

    Leatherman, S.P.

    1994-01-01

    A review is given of the problems small island nations face with respect to sea level rise caused by global warming. Many small island nations are very vulnerable to sea level rise. Particularly at risk are coral reef atolls, which are generally quite small, lie within three metres of current sea levels, and have no land at higher elevations to relocate populations and economic activity. Volcanic islands in the Pacific have high ground, but it is largely rugged, high relief and soil-poor. The most vulnerable islands are those that consist entirely of atolls and reef islands, such as Kirabai, Maldives, Tokelau and Tuvalu. Small island states, which by themselves have little power or influence in world affairs, have banded together to form the Strategic Alliance of Small Island States (AOSIS). This alliance had grown to include 42 states by the time of the 1992 U.N. Earth Summit. Although the greenhouse effect is mainly caused by industrial nations, developing countries will suffer the most from it. Choices of response strategy will depend on environmental, economic and social factors. Most small island nations do not have the resources to fight sea level rise in the way that the Dutch have. Retreat can occur as a gradual process or as catastrophic abandonment. Prohibiting construction close to the water's edge is a good approach. Sea level histories for each island state should be compiled and updated, island geomorphology and settlement patterns should be surveyed to determine risk areas, storm regimes should be determined, and information on coastal impacts of sea level rise should be disseminated to the public

  4. Recent Arctic sea level variations from satellites

    OpenAIRE

    Ole Baltazar Andersen; Gaia ePiccioni

    2016-01-01

    Sea level monitoring in the Arctic region has always been an extreme challenge for remote sensing, and in particular for satellite altimetry. Despite more than two decades of observations, altimetry is still limited in the inner Arctic Ocean. We have developed an updated version of the Danish Technical University's (DTU) Arctic Ocean altimetric sea level timeseries starting in 1993 and now extended up to 2015 with CryoSat-2 data. The time-series covers a total of 23 years, which allows higher...

  5. Sea level monitoring in Africa | Woodworth | African Journal of ...

    African Journals Online (AJOL)

    Information Network for Africa (ODINAfrica) programme are described and a survey of currently existing and planned sea level stations in Africa is presented, together with information on where data for existing stations may be found. Keywords: sea level data applications, sea level data telemetry, sea level networks. African ...

  6. Holocene sea-level fluctuation in the southern hemisphere

    Science.gov (United States)

    Isla, Federico Ignacio

    If rising sea levels dominate in the northern hemisphere (NH), falling or fluctuating sea levels predominate in the southern hemisphere (SH). Endogenic processes (tectonics, isostasy or geoidal changes) could explain local or regional mean sea level (MSL) fluctuations but not an hemispherical one. Evidence from South America, Africa, Antarctica, Australia and the Pacific and Indian Oceans suggest that the Holocene transgression rose above the present MSL, in higher latitudes before the tropics. By plotting latitude against the age of MSL arrival at present coasts, good correlation is observed. Oceanic salinity mixing has been already proposed to explain this mid-Holocene sea-level fluctuation. Climate could be the only factor responsible for this hemisphere-wide behavior of MSL. It has been suggested previously that the climate of the SH precedes that of the NH by 3000 years. The climatic optimum, or maximum warmth, occurred predominantly about 6000 BP in the NH, but about 10-9000 BP in the SH. Short-term climatic effects on the sea level (monsoons, southern oscillation/El Niño phenomena) should have significant occurrences during the past in the windiest oceanic hemisphere. This latitudinal trend in former MSL should be considered when using shorelines as reference points for measuring vertical crustal movements.

  7. Impact of sea level rise on tide gate function.

    Science.gov (United States)

    Walsh, Sean; Miskewitz, Robert

    2013-01-01

    Sea level rise resulting from climate change and land subsidence is expected to severely impact the duration and associated damage resulting from flooding events in tidal communities. These communities must continuously invest resources for the maintenance of existing structures and installation of new flood prevention infrastructure. Tide gates are a common flood prevention structure for low-lying communities in the tidal zone. Tide gates close during incoming tides to prevent inundation from downstream water propagating inland and open during outgoing tides to drain upland areas. Higher downstream mean sea level elevations reduce the effectiveness of tide gates by impacting the hydraulics of the system. This project developed a HEC-RAS and HEC-HMS model of an existing tide gate structure and its upland drainage area in the New Jersey Meadowlands to simulate the impact of rising mean sea level elevations on the tide gate's ability to prevent upstream flooding. Model predictions indicate that sea level rise will reduce the tide gate effectiveness resulting in longer lasting and deeper flood events. The results indicate that there is a critical point in the sea level elevation for this local area, beyond which flooding scenarios become dramatically worse and would have a significantly negative impact on the standard of living and ability to do business in one of the most densely populated areas of America.

  8. Tides, surges and mean sea-level

    National Research Council Canada - National Science Library

    Pugh, D. T

    1987-01-01

    .... Interest in mean sea-level changes has recently been focused on the possibility of significant increases over the coming century as a result of global warming. Examples of applications from North America, Europe and other parts of the world are included.

  9. Investigating Margin and Grounding Line Dynamics with a Coupled Ice and Sea Level Model

    Science.gov (United States)

    Kuchar, J.; Milne, G. A.

    2017-12-01

    We present results from the coupling of an adaptive mesh glaciological model (BISICLES) with a model of glacial isostatic adjustment and sea level. We apply this coupled model to study the deglaciation of the Greenland Ice Sheet (GrIS) from the last glacial maximum. The proximity of the GrIS to the much larger Laurentide results in an east-west gradient in sea level rates across Greenland during the deglaciation. We investigate the impacts of this sea level gradient on ice and grounding line dynamics at the margins, as well as the influence of both local and non-local ice on sea level and ice dynamics.

  10. Analysis of Sea Level Rise in Action

    Science.gov (United States)

    Gill, K. M.; Huang, T.; Quach, N. T.; Boening, C.

    2016-12-01

    NASA's Sea Level Change Portal provides scientists and the general public with "one-stop" source for current sea level change information and data. Sea Level Rise research is a multidisciplinary research and in order to understand its causes, scientists must be able to access different measurements and to be able to compare them. The portal includes an interactive tool, called the Data Analysis Tool (DAT), for accessing, visualizing, and analyzing observations and models relevant to the study of Sea Level Rise. Using NEXUS, an open source, big data analytic technology developed at the Jet Propulsion Laboratory, the DAT is able provide user on-the-fly data analysis on all relevant parameters. DAT is composed of three major components: A dedicated instance of OnEarth (a WMTS service), NEXUS deep data analytic platform, and the JPL Common Mapping Client (CMC) for web browser based user interface (UI). Utilizing the global imagery, a user is capable of browsing the data in a visual manner and isolate areas of interest for further study. The interfaces "Analysis" tool provides tools for area or point selection, single and/or comparative dataset selection, and a range of options, algorithms, and plotting. This analysis component utilizes the Nexus cloud computing platform to provide on-demand processing of the data within the user-selected parameters and immediate display of the results. A RESTful web API is exposed for users comfortable with other interfaces and who may want to take advantage of the cloud computing capabilities. This talk discuss how DAT enables on-the-fly sea level research. The talk will introduce the DAT with an end-to-end tour of the tool with exploration and animating of available imagery, a demonstration of comparative analysis and plotting, and how to share and export data along with images for use in publications/presentations. The session will cover what kind of data is available, what kind of analysis is possible, and what are the outputs.

  11. Sea level hazards: Altimetric monitoring of tsunamis and sea level rise

    Science.gov (United States)

    Hamlington, Benjamin Dillon

    Whether on the short timescale of an impending tsunami or the much longer timescale of climate change-driven sea level rise, the threat stemming from rising and inundating ocean waters is a great concern to coastal populations. Timely and accurate observations of potentially dangerous changes in sea level are vital in determining the precautionary steps that need to be taken in order to protect coastal communities. While instruments from the past have provided in situ measurements of sea level at specific locations across the globe, satellites can be used to provide improved spatial and temporal sampling of the ocean in addition to producing more accurate measurements. Since 1993, satellite altimetry has provided accurate measurements of sea surface height (SSH) with near-global coverage. Not only have these measurements led to the first definitive estimates of global mean sea level rise, satellite altimetry observations have also been used to detect tsunami waves in the open ocean where wave amplitudes are relatively small, a vital step in providing early warning to those potentially affected by the impending tsunami. The use of satellite altimetry to monitor two specific sea level hazards is examined in this thesis. The first section will focus on the detection of tsunamis in the open ocean for the purpose of providing early warning to coastal inhabitants. The second section will focus on estimating secular trends using satellite altimetry data with the hope of improving our understanding of future sea level change. Results presented here will show the utility of satellite altimetry for sea level monitoring and will lay the foundation for further advancement in the detection of the two sea level hazards considered.

  12. DUACS: Toward High Resolution Sea Level Products

    Science.gov (United States)

    Faugere, Y.; Gerald, D.; Ubelmann, C.; Claire, D.; Pujol, M. I.; Antoine, D.; Desjonqueres, J. D.; Picot, N.

    2016-12-01

    The DUACS system produces, as part of the CNES/SALP project, and the Copernicus Marine Environment and Monitoring Service, high quality multimission altimetry Sea Level products for oceanographic applications, climate forecasting centers, geophysic and biology communities... These products consist in directly usable and easy to manipulate Level 3 (along-track cross-calibrated SLA) and Level 4 products (multiple sensors merged as maps or time series) and are available in global and regional version (Mediterranean Sea, Arctic, European Shelves …).The quality of the products is today limited by the altimeter technology "Low Resolution Mode" (LRM), and the lack of available observations. The launch of 2 new satellites in 2016, Jason-3 and Sentinel-3A, opens new perspectives. Using the global Synthetic Aperture Radar mode (SARM) coverage of S3A and optimizing the LRM altimeter processing (retracking, editing, ...) will allow us to fully exploit the fine-scale content of the altimetric missions. Thanks to this increase of real time altimetry observations we will also be able to improve Level-4 products by combining these new Level-3 products and new mapping methodology, such as dynamic interpolation. Finally these improvements will benefit to downstream products : geostrophic currents, Lagrangian products, eddy atlas… Overcoming all these challenges will provide major upgrades of Sea Level products to better fulfill user needs.

  13. Holocene sea-level changes in the Falkland Islands

    Science.gov (United States)

    Newton, Tom; Gehrels, Roland; Daley, Tim; Long, Antony; Bentley, Mike

    2014-05-01

    In many locations in the southern hemisphere, relative sea level (RSL) reached its maximum position during the middle Holocene. This highstand is used by models of glacial isostatic adjustment (GIA) to constrain the melt histories of the large ice sheets, particularly Antarctica. In this paper we present the first Holocene sea-level record from the Falkland Islands (Islas Malvinas), an archipelago located on the Patagonian continental shelf about 500 km east of mainland South America at a latitude of ca. 52 degrees. Unlike coastal locations in southernmost South America, Holocene sea-level data from the Falklands are not influenced by tectonics, local ice loading effects and large tidal ranges such that GIA and ice-ocean mass flux are the dominant drivers of RSL change. Our study site is a salt marsh located in Swan Inlet in East Falkland, around 50 km southwest of Stanley. This is the largest and best developed salt marsh in the Falkland Islands. Cores were collected in 2005 and 2013. Lithostratigraphic analyses were complemented by analyses of foraminifera, testate amoebae and diatoms to infer palaeoenvironments. The bedrock, a Permian black shale, is overlain by grey-brown organic salt-marsh clay, up to 90 cm thick, which, in a landward direction, is replaced by freshwater organic sediments. Overlying these units are medium-coarse sands with occasional pebbles, up to 115 cm thick, containing tidal flat foraminifera. The sandy unit is erosively overlain by a grey-brown organic salt-marsh peat which extends up to the present surface. Further away from the sea this unit is predominantly of freshwater origin. Based on 13 radiocarbon dates we infer that prior to ~9.5 ka sea level was several metres below present. Under rising sea levels a salt marsh developed which was suddenly drowned around 8.4 ka, synchronous with a sea-level jump known from northern hemisphere locations. Following the drowning, RSL rose to its maximum position around 7 ka, less than 0.5 m above

  14. Sea level rise and the geoid: factor analysis approach

    Directory of Open Access Journals (Sweden)

    Alexey Sadovski

    2013-08-01

    Full Text Available Sea levels are rising around the world, and this is a particular concern along most of the coasts of the United States. A 1989 EPA report shows that sea levels rose 5-6 inches more than the global average along the Mid-Atlantic and Gulf Coasts in the last century. The main reason for this is coastal land subsidence. This sea level rise is considered more as relative sea level rise than global sea level rise. Thus, instead of studying sea level rise globally, this paper describes a statistical approach by using factor analysis of regional sea level rates of change. Unlike physical models and semi-empirical models that attempt to approach how much and how fast sea levels are changing, this methodology allows for a discussion of the factor(s that statistically affects sea level rates of change, and seeks patterns to explain spatial correlations.

  15. The future for the Global Sea Level Observing System (GLOSS) Sea Level Data Rescue

    Science.gov (United States)

    Bradshaw, Elizabeth; Matthews, Andrew; Rickards, Lesley; Aarup, Thorkild

    2016-04-01

    Historical sea level data are rare and unrepeatable measurements with a number of applications in climate studies (sea level rise), oceanography (ocean currents, tides, surges), geodesy (national datum), geophysics and geology (coastal land movements) and other disciplines. However, long-term time series are concentrated in the northern hemisphere and there are no records at the Permanent Service for Mean Sea Level (PSMSL) global data bank longer than 100 years in the Arctic, Africa, South America or Antarctica. Data archaeology activities will help fill in the gaps in the global dataset and improve global sea level reconstruction. The Global Sea Level Observing System (GLOSS) is an international programme conducted under the auspices of the WMO-IOC Joint Technical Commission for Oceanography and Marine Meteorology. It was set up in 1985 to collect long-term tide gauge observations and to develop systems and standards "for ocean monitoring and flood warning purposes". At the GLOSS-GE-XIV Meeting in 2015, GLOSS agreed on a number of action items to be developed in the next two years. These were: 1. To explore mareogram digitisation applications, including NUNIEAU (more information available at: http://www.mediterranee.cerema.fr/logiciel-de-numerisation-des-enregistrements-r57.html) and other recent developments in scanning/digitisation software, such as IEDRO's Weather Wizards program, to see if they could be used via a browser. 2. To publicise sea level data archaeology and rescue by: • maintaining and regularly updating the Sea Level Data Archaeology page on the GLOSS website • strengthening links to the GLOSS data centres and data rescue organisations e.g. linking to IEDRO, ACRE, RDA • restarting the sea level data rescue blog with monthly posts. 3. Investigate sources of funding for data archaeology and rescue projects. 4. Propose "Guidelines" for rescuing sea level data. These action items will aid the discovery, scanning, digitising and quality control

  16. Tracking multidecadal trends in sea level using coral microatolls

    Science.gov (United States)

    Majewski, Jedrzej; Pham, Dat; Meltzner, Aron; Switzer, Adam; Horton, Benjamin; Heng, Shu Yun; Warrick, David

    2015-04-01

    Tracking multidecadal trends in sea level using coral microatolls Jędrzej M. Majewski 1, Dat T. Pham1, Aron J. Meltzner 1, Adam D. Switzer 1, Benjamin P. Horton2, Shu Yun Heng1, David Warrick3, 1 Earth Observatory of Singapore, Nanyang Technological University, Singapore 2 Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA 3 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA Coral microatolls can be used to study relative sea-level change at multidecadal timescales associated with vertical land movements, climate induced sea-level rise and other oceanographic phenomena such as the El Niño/Southern Oscillation (ENSO) or Indian Ocean Dipole (IOD) with the assumption that the highest level of survival (HLS) of coral microatolls track sea level over the course of their lifetimes. In this study we compare microatoll records covering from as early as 1883 through 2013, from two sites in Indonesia, with long records (>20 years) from proximal tide gauges, satellite altimetry, and other sea-level reconstructions. We compared the HLS time series derived from open-ocean and moated (or ponded) microatolls on tectonically stable Belitung Island and a potentially tectonically active setting in Mapur Island, with sea-level reconstructions for 1950-2011. The sea-level reconstructions are based on ground and satellite measurements, combining a tide model with the Estimating the Circulation and Climate of the Ocean (ECCO) model. Our results confirm that open-ocean microatolls do track low water levels at multi decadal time scales and can be used as a proxy for relative sea level (RSL) over time. However, microatolls that are even partially moated are unsuitable and do not track RSL; rather, their growth patterns likely reflect changes in the elevation of the sill of the local pond, as reported by earlier authors. Our ongoing efforts will include an attempt to recognize similarities in moated

  17. Course of sea-level change

    Science.gov (United States)

    Carlowicz, Michael

    This summer, the Environment and Climate Program of the European Union will offer an advanced study course on “sea-level changes on micro to macro timescales: measurements, modeling, interpretation, and application.” The short course will be taught from July 1-12 at the Aesclepon Conference Center on the island of Kos, Greece.The interdisciplinary course is designed to bring together at least 40 students from different disciplines in an attempt to share and disseminate fundamental ideas about sea level change, focusing particularly on changes influenced by anthropogenic factors. Participants will be selected by a scientific panel; the European Union will conduct the course free of charge and will provide free lodging. Students must pay for their own travel expenses and food.

  18. Sea level rise and the geoid: factor analysis approach

    OpenAIRE

    Song, Hongzhi; Sadovski, Alexey; Jeffress, Gary

    2013-01-01

    Sea levels are rising around the world, and this is a particular concern along most of the coasts of the United States. A 1989 EPA report shows that sea levels rose 5-6 inches more than the global average along the Mid-Atlantic and Gulf Coasts in the last century. The main reason for this is coastal land subsidence. This sea level rise is considered more as relative sea level rise than global sea level rise. Thus, instead of studying sea level rise globally, this paper describes a statistical...

  19. Cellular-based sea level gauge

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, R.G.P.; Joseph, A.

    treaties with greater transparency. Among the various communication technologies used for real-time transmission of sea-level data are the wired telephone connection, VHF/UHF transceivers, satellite transmit terminals and cellular connectivity. Wired... telephone connections are severely susceptible to loss of connectivity during natural disasters such as storm surges, primarily because of telephone line breakage. Communication via VHF/UHF transceivers is limited by line-of-sight distance between...

  20. Mechanisms of long-term mean sea level variability in the North Sea

    Science.gov (United States)

    Dangendorf, Sönke; Calafat, Francisco; Øie Nilsen, Jan Even; Richter, Kristin; Jensen, Jürgen

    2015-04-01

    We examine mean sea level (MSL) variations in the North Sea on timescales ranging from months to decades under the consideration of different forcing factors since the late 19th century. We use multiple linear regression models, which are validated for the second half of the 20th century against the output of a state-of-the-art tide+surge model (HAMSOM), to determine the barotropic response of the ocean to fluctuations in atmospheric forcing. We demonstrate that local atmospheric forcing mainly triggers MSL variability on timescales up to a few years, with the inverted barometric effect dominating the variability along the UK and Norwegian coastlines and wind (piling up the water along the coast) controlling the MSL variability in the south from Belgium up to Denmark. However, in addition to the large inter-annual sea level variability there is also a considerable fraction of decadal scale variability. We show that on decadal timescales MSL variability in the North Sea mainly reflects steric changes, which are mostly remotely forced. A spatial correlation analysis of altimetry observations and baroclinic ocean model outputs suggests evidence for a coherent signal extending from the Norwegian shelf down to the Canary Islands. This supports the theory of longshore wind forcing along the eastern boundary of the North Atlantic causing coastally trapped waves to propagate along the continental slope. With a combination of oceanographic and meteorological measurements we demonstrate that ~80% of the decadal sea level variability in the North Sea can be explained as response of the ocean to longshore wind forcing, including boundary wave propagation in the Northeast Atlantic. These findings have important implications for (i) detecting significant accelerations in North Sea MSL, (ii) the conceptual set up of regional ocean models in terms of resolution and boundary conditions, and (iii) the development of adequate and realistic regional climate change projections.

  1. Monitoring sea level and sea surface temperature trends from ERS satellites

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Knudsen, Per; Beckley, B.

    2002-01-01

    Data from the two ESA satellites ERS-1 and ERS-2 are used in global and regional analysis of sea level and sea surface temperature trends over the last, 7.8 years. T he ERS satellites and in the future the ENVISAT satellite provide unique opportunity for monitoring both changes in sea level and sea...

  2. Grain-size based sea-level reconstruction in the south Bohai Sea during the past 135 kyr

    Science.gov (United States)

    Yi, Liang; Chen, Yanping

    2013-04-01

    Future anthropogenic sea-level rise and its impact on coastal regions is an important issue facing human civilizations. Due to the short nature of the instrumental record of sea-level change, development of proxies for sea-level change prior to the advent of instrumental records is essential to reconstruct long-term background sea-level changes on local, regional and global scales. Two of the most widely used approaches for past sea-level changes are: (1) exploitation of dated geomorphologic features such as coastal sands (e.g. Mauz and Hassler, 2000), salt marsh (e.g. Madsen et al., 2007), terraces (e.g. Chappell et al., 1996), and other coastal sediments (e.g. Zong et al., 2003); and (2) sea-level transfer functions based on faunal assemblages such as testate amoebae (e.g. Charman et al., 2002), foraminifera (e.g. Chappell and Shackleton, 1986; Horton, 1997), and diatoms (e.g. Horton et al., 2006). While a variety of methods has been developed to reconstruct palaeo-changes in sea level, many regions, including the Bohai Sea, China, still lack detailed relative sea-level curves extending back to the Pleistocene (Yi et al., 2012). For example, coral terraces are absent in the Bohai Sea, and the poor preservation of faunal assemblages makes development of a transfer function for a relative sea-level reconstruction unfeasible. In contrast, frequent alternations between transgression and regression has presumably imprinted sea-level change on the grain size distribution of Bohai Sea sediments, which varies from medium silt to coarse sand during the late Quaternary (IOCAS, 1985). Advantages of grainsize-based relative sea-level transfer function approaches are that they require smaller sample sizes, allowing for replication, faster measurement and higher spatial or temporal resolution at a fraction of the cost of detail micro-palaeontological analysis (Yi et al., 2012). Here, we employ numerical methods to partition sediment grain size using a combined database of

  3. Deep Ocean Contribution to Sea Level Rise

    Science.gov (United States)

    Chang, L.; Sun, W.; Tang, H.; Wang, Q.

    2017-12-01

    The ocean temperature and salinity change in the upper 2000m can be detected by Argo floats, so we can know the steric height change of the ocean. But the ocean layers above 2000m represent only 50% of the total ocean volume. Although the temperature and salinity change are small compared to the upper ocean, the deep ocean contribution to sea level might be significant because of its large volume. There has been some research on the deep ocean rely on the very sparse situ observation and are limited to decadal and longer-term rates of change. The available observational data in the deep ocean are too spares to determine the temporal variability, and the long-term changes may have a bias. We will use the Argo date and combine the situ data and topographic data to estimate the temperature and salinity of the sea water below 2000m, so we can obtain a monthly data. We will analyze the seasonal and annual change of the steric height change due to the deep ocean between 2005 and 2016. And we will evaluate the result combination the present-day satellite and in situ observing systems. The deep ocean contribution can be inferred indirectly as the difference between the altimetry minus GRACE and Argo-based steric sea level.

  4. Annual mean sea level and its sensitivity to wind climate

    Science.gov (United States)

    Gerkema, Theo; Duran Matute, Matias

    2017-04-01

    the west-east component of the net wind energy vector, with some further improvement if one also includes the south-north component and annual mean atmospheric pressure. Knowledge of these local correlations can then be used to correct values of annual mean sea for these atmospheric effects. This halves the margin of error (expressed as 95%-confidence interval) for linear trends in a 20-year sea level record. The sensitivity on wind direction has a regional variability, even on a small scale like the Dutch Wadden Sea. Model results illustrate the detailed spatial patterns in inter-annual variability of annual mean sea level. This study also implies that climatic changes in wind direction, or in the strength of winds from a specific direction, may affect local annual mean sea level quite significantly.

  5. Sea Levels Online: Sea Level Variations of the United States Derived from National Water Level Observation Network Stations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water level records are a combination of the fluctuations of the ocean and the vertical land motion at the location of the station. Monthly mean sea level (MSL)...

  6. Monthly Variations in Sea Level at the Island of Zanzibar

    African Journals Online (AJOL)

    The trend in sea level. (9%) appeared ... There is a strong likelihood that physical processes other .... a bell-shaped curve. To avoid erroneous conclusions, residual analysis tests were carried ..... prediction of sea level, regardless of the units ...

  7. Expected extreme sea levels at Forsmark and Laxemar-Simpevarp up until year 2100

    International Nuclear Information System (INIS)

    Brydsten, Lars; Engqvist, Anders; Naeslund, Jens-Ove; Lindborg, Tobias

    2009-01-01

    Literature data on factors that can affect the highest expected shoreline during the operational lifetime of a final repository up until ca 2100 AD have been compiled for Forsmark and Laxemar/Simpevarp. The study takes into consideration eustasy (global sea level), isostasy (isostatic rebound) and their trends, as well as regional (North Sea) and local (Baltic Sea) annual extremes of today's sea levels and those in year 2100. The most uncertain factor of these is the future global sea level change. For this factor, three possible scenarios have been included from the literature, forming an rough uncertainty interval around a case with an 'intermediate' global sea level. To this end, the study thus makes use of information on global sea level change that has been published since the IPCC's (UN Intergovernmental Panel on Climate Change) most recent report (2007). The local cumulative impact on the shoreline of the eustatic and isostatic components for both the Forsmark and Laxemar/Simpevarp coastal areas is that the maximum sea level occurs at the end of the investigation period, by year 2100. The interaction of these estimates is discussed in terms of coastal oceanographic aspects and estimated return periods for local extreme sea level-impacting events, including estimated storm surge. Maximum sea levels in year 2100 based on the sea level rise estimates by Rahmstorf are + 254 cm for Forsmark and + 297 cm for Laxemar/Simpevarp, both of these levels with an uncertainty interval of about ± 70 cm. The numbers apply for the worst possible case in regard to future sea level rise, and for occasions of short duration during heavy storms. In this context it is important to note that the data on which these estimates are based are the subject of intense research, and that revisions are therefore to be expected

  8. Expected extreme sea levels at Forsmark and Laxemar-Simpevarp up until year 2100

    Energy Technology Data Exchange (ETDEWEB)

    Brydsten, Lars (Umeaa Univ., Umeaa (Sweden)); Engqvist, Anders (Royal Institute of Technology, Stockholm (Sweden)); Naeslund, Jens-Ove; Lindborg, Tobias (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

    2009-01-15

    Literature data on factors that can affect the highest expected shoreline during the operational lifetime of a final repository up until ca 2100 AD have been compiled for Forsmark and Laxemar/Simpevarp. The study takes into consideration eustasy (global sea level), isostasy (isostatic rebound) and their trends, as well as regional (North Sea) and local (Baltic Sea) annual extremes of today's sea levels and those in year 2100. The most uncertain factor of these is the future global sea level change. For this factor, three possible scenarios have been included from the literature, forming an rough uncertainty interval around a case with an 'intermediate' global sea level. To this end, the study thus makes use of information on global sea level change that has been published since the IPCC's (UN Intergovernmental Panel on Climate Change) most recent report (2007). The local cumulative impact on the shoreline of the eustatic and isostatic components for both the Forsmark and Laxemar/Simpevarp coastal areas is that the maximum sea level occurs at the end of the investigation period, by year 2100. The interaction of these estimates is discussed in terms of coastal oceanographic aspects and estimated return periods for local extreme sea level-impacting events, including estimated storm surge. Maximum sea levels in year 2100 based on the sea level rise estimates by Rahmstorf are + 254 cm for Forsmark and + 297 cm for Laxemar/Simpevarp, both of these levels with an uncertainty interval of about +- 70 cm. The numbers apply for the worst possible case in regard to future sea level rise, and for occasions of short duration during heavy storms. In this context it is important to note that the data on which these estimates are based are the subject of intense research, and that revisions are therefore to be expected

  9. Estimating sea-level allowances for Atlantic Canada under conditions of uncertain sea-level rise

    Directory of Open Access Journals (Sweden)

    B. Greenan

    2015-03-01

    Full Text Available This paper documents the methodology of computing sea-level rise allowances for Atlantic Canada in the 21st century under conditions of uncertain sea-level rise. The sea-level rise allowances are defined as the amount by which an asset needs to be raised in order to maintain the same likelihood of future flooding events as that site has experienced in the recent past. The allowances are determined by combination of the statistics of present tides and storm surges (storm tides and the regional projections of sea-level rise and associated uncertainty. Tide-gauge data for nine sites from the Canadian Atlantic coast are used to derive the scale parameters of present sea-level extremes using the Gumbel distribution function. The allowances in the 21st century, with respect to the year 1990, were computed for the Intergovernmental Panel on Climate Change (IPCC A1FI emission scenario. For Atlantic Canada, the allowances are regionally variable and, for the period 1990–2050, range between –13 and 38 cm while, for the period 1990–2100, they range between 7 and 108 cm. The negative allowances in the northern Gulf of St. Lawrence region are caused by land uplift due to glacial isostatic adjustment (GIA.

  10. Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover and fast ice decay

    Directory of Open Access Journals (Sweden)

    P. Itkin

    2017-10-01

    Full Text Available Ice retreat in the eastern Eurasian Arctic is a consequence of atmospheric and oceanic processes and regional feedback mechanisms acting on the ice cover, both in winter and summer. A correct representation of these processes in numerical models is important, since it will improve predictions of sea ice anomalies along the Northeast Passage and beyond. In this study, we highlight the importance of winter ice dynamics for local summer sea ice anomalies in thickness, volume and extent. By means of airborne sea ice thickness surveys made over pack ice areas in the south-eastern Laptev Sea, we show that years of offshore-directed sea ice transport have a thinning effect on the late-winter sea ice cover. To confirm the preconditioning effect of enhanced offshore advection in late winter on the summer sea ice cover, we perform a sensitivity study using a numerical model. Results verify that the preconditioning effect plays a bigger role for the regional ice extent. Furthermore, they indicate an increase in volume export from the Laptev Sea as a consequence of enhanced offshore advection, which has far-reaching consequences for the entire Arctic sea ice mass balance. Moreover we show that ice dynamics in winter not only preconditions local summer ice extent, but also accelerate fast-ice decay.

  11. Holocene Sea-Level Database For The Caribbean Region

    Science.gov (United States)

    Khan, N. S.; Horton, B.; Engelhart, S. E.; Peltier, W. R.; Scatena, F. N.; Vane, C. H.; Liu, S.

    2013-12-01

    Holocene relative sea-level (RSL) records from far-field locations are important for understanding the driving mechanisms controlling the nature and timing of the mid-late Holocene reduction in global meltwaters and providing background rates of late Holocene RSL change with which to compare the magnitude of 20th century RSL rise. The Caribbean region has traditionally been considered far-field (i.e., with negligible glacio-isostatic adjustment (GIA) influence), although recent investigations indicate otherwise. Here, we consider the spatial variability in glacio-isostatic, tectonic and local contributions on RSL records from the circum-Caribbean region to infer a Holocene eustatic sea-level signal. We have constructed a database of quality-controlled, spatially comprehensive, Holocene RSL observations for the circum-Caribbean region. The database contains over 500 index points, which locate the position of RSL in time and space. The database incorporates sea-level observations from a latitudinal range of 5°N to 25°N and longitudinal range of 55°W to 90°W. We include sea-level observations from 11 ka BP to present, although the majority of the index points in the database are younger than 8 ka BP. The database is sub-divided into 13 regions based on the distance from the former Laurentide Ice Sheet and regional tectonic setting. The index points were primarily derived from mangrove peat deposits, which in the Caribbean form in the upper half of the tidal range, and corals (predominantly Acropora palmata), the growth of which is constrained to the upper 5 m of water depth. The index points are classified on the basis of their susceptibility to compaction (e.g., intercalated, basal). The influence of temporal changes in tidal range on index points is also considered. The sea-level reconstructions demonstrate that RSL did not exceed the present height (0 m) during the Holocene in the majority of locations, except at sites in Suriname/Guayana and possibly Trinidad

  12. Anthropogenic forcing dominates sea level rise since 1850

    DEFF Research Database (Denmark)

    Jevrejeva, Svetlana; Grinsted, Aslak; Moore, John

    2009-01-01

    The rate of sea level rise and its causes are topics of active debate. Here we use a delayed response statistical model to attribute the past 1000 years of sea level variability to various natural (volcanic and solar radiative) and anthropogenic (greenhouse gases and aerosols) forcings. We show...... that until 1800 the main drivers of sea level change are volcanic and solar radiative forcings. For the past 200 years sea level rise is mostly associated with anthropogenic factors. Only 4 ± 1.5 cm (25% of total sea level rise) during the 20th century is attributed to natural forcings, the remaining 14 ± 1...

  13. Relative Sea Level, Tidal Range, and Extreme Water Levels in Boston Harbor from 1825 to 2016

    Science.gov (United States)

    Talke, S. A.; Kemp, A.; Woodruff, J. D.

    2017-12-01

    Long time series of water-level measurements made by tide gauges provide a rich and valuable observational history of relative sea-level change, the frequency and height of extreme water levels and evolving tidal regimes. However, relatively few locations have available tide-gauge records longer than 100 years and most of these places are in northern Europe. This spatio-temporal distribution hinders efforts to understand global-, regional- and local-scale trends. Using newly-discovered archival measurements, we constructed a 200 year, instrumental record of water levels, tides, and storm surges in Boston Harbor. We detail the recovery, datum reconstruction, digitization, quality assurance, and analysis of this extended observational record. Local, decadally-averaged relative sea-level rose by 0.28 ± 0.05 m since the 1820s, with an acceleration of 0.023 ±0.009 mm/yr2. Approximately 0.13 ± 0.02 m of the observed RSL rise occurred due to ongoing glacial isostatic adjustment, and the remainder occurred due to changes in ocean mass and volume associated with the onset of modern mean sea-level rise. Change-point analysis of the new relative sea level record confirms that anthropogenic rise began in 1924-1932, which is in agreement with global mean sea level estimates from the global tide gauge network. Tide range decreased by 5.5% between 1830 and 1910, likely due in large part to anthropogenic development. Storm tides in Boston Harbor are produced primarily by extratropical storms during the November-April time frame. The three largest storm tides occurred in 1851, 1909, and 1978. Because 90% of the top 20 storm tides since 1825 occurred during a spring tide, the secular change in tide range contributes to a slight reduction in storm tide magnitudes. However, non-stationarity in storm hazard was historically driven primarily by local relative sea-level rise; a modest 0.2 m increase in relative sea level reduces the 100 year high water mark to a once-in-10 year event.

  14. Implications of Sea Level Rise on Coastal Flood Hazards

    Science.gov (United States)

    Roeber, V.; Li, N.; Cheung, K.; Lane, P.; Evans, R. L.; Donnelly, J. P.; Ashton, A. D.

    2012-12-01

    Recent global and local projections suggest the sea level will be on the order of 1 m or higher than the current level by the end of the century. Coastal communities and ecosystems in low-lying areas are vulnerable to impacts resulting from hurricane or large swell events in combination with sea-level rise. This study presents the implementation and results of an integrated numerical modeling package to delineate coastal inundation due to storm landfalls at future sea levels. The modeling package utilizes a suite of numerical models to capture both large-scale phenomena in the open ocean and small-scale processes in coastal areas. It contains four components to simulate (1) meteorological conditions, (2) astronomical tides and surge, (3) wave generation, propagation, and nearshore transformation, and (4) surf-zone processes and inundation onto dry land associated with a storm event. Important aspects of this package are the two-way coupling of a spectral wave model and a storm surge model as well as a detailed representation of surf and swash zone dynamics by a higher-order Boussinesq-type wave model. The package was validated with field data from Hurricane Ivan of 2005 on the US Gulf coast and applied to tropical and extratropical storm scenarios respectively at Eglin, Florida and Camp Lejeune, North Carolina. The results show a nonlinear increase of storm surge level and nearshore wave energy with a rising sea level. The exacerbated flood hazard can have major consequences for coastal communities with respect to erosion and damage to infrastructure.

  15. Continuous sea-level reconstructions beyond the Pleistocene: improving the Mediterranean sea-level method

    Science.gov (United States)

    Grant, K.; Rohling, E. J.; Amies, J.

    2017-12-01

    Sea-level (SL) reconstructions over glacial-interglacial timeframes are critical for understanding the equilibrium response of ice sheets to sustained warming. In particular, continuous and high-resolution SL records are essential for accurately quantifying `natural' rates of SL rise. Global SL changes are well-constrained since the last glacial maximum ( 20,000 years ago, ky) by radiometrically-dated corals and paleoshoreline data, and fairly well-constrained over the last glacial cycle ( 150 ky). Prior to that, however, studies of ice-volume:SL relationships tend to rely on benthic δ18O, as geomorphological evidence is far more sparse and less reliably dated. An alternative SL reconstruction method (the `marginal basin' approach) was developed for the Red Sea over 500 ky, and recently attempted for the Mediterranean over 5 My (Rohling et al., 2014, Nature). This method exploits the strong sensitivity of seawater δ18O in these basins to SL changes in the relatively narrow and shallow straits which connect the basins with the open ocean. However, the initial Mediterranean SL method did not resolve sea-level highstands during Northern Hemisphere insolation maxima, when African monsoon run-off - strongly depleted in δ18O - reached the Mediterranean. Here, we present improvements to the `marginal basin' sea-level reconstruction method. These include a new `Med-Red SL stack', which combines new probabilistic Mediterranean and Red Sea sea-level stacks spanning the last 500 ky. We also show how a box model-data comparison of water-column δ18O changes over a monsoon interval allows us to quantify the monsoon versus SL δ18O imprint on Mediterranean foraminiferal carbonate δ18O records. This paves the way for a more accurate and fully continuous SL reconstruction extending back through the Pliocene.

  16. Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

    Science.gov (United States)

    Cronin, Thomas M.; O'Regan, Matt; Pearce, Christof; Gemery, Laura; Toomey, Michael; Semiletov, Igor

    2017-01-01

    Deglacial (12.8–10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM;  ∼  24 kiloannum or ka) minimum sea level of  ∼  125–130 meters below sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( ∼  400 cm of core depth) is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42–47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.

  17. Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

    Directory of Open Access Journals (Sweden)

    T. M. Cronin

    2017-09-01

    Full Text Available Deglacial (12.8–10.7 ka sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1 and multicore SWERUS-L2-4-MC1 (4-MC1, and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1. Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM;  ∼  24 kiloannum or ka minimum sea level of  ∼  125–130 meters below sea level (m b.s.l.. Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1 followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( ∼  400 cm of core depth is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42–47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.

  18. Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins

    Science.gov (United States)

    Cronin, Thomas M.; O'Regan, Matt; Pearce, Christof; Gemery, Laura; Toomey, Michael; Semiletov, Igor; Jakobsson, Martin

    2017-09-01

    Deglacial (12.8-10.7 ka) sea level history on the East Siberian continental shelf and upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores 4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth, respectively, only a few meters above the global last glacial maximum (LGM; ˜ 24 kiloannum or ka) minimum sea level of ˜ 125-130 meters below sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleodepths, the data reveal a dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea level rise beginning at roughly 11.4 to 10.8 ka ( ˜ 400 cm of core depth) is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was up to 42-47 m lower than predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.

  19. Updating Maryland's sea-level rise projections

    Science.gov (United States)

    Boesch, Donald F.; Atkinson, Larry P.; Boicourt, William C.; Boon, John D.; Cahoon, Donald R.; Dalrymple, Robert A.; Ezer, Tal; Horton, Benjamin P.; Johnson, Zoe P.; Kopp, Robert E.; Li, Ming; Moss, Richard H.; Parris, Adam; Sommerfield, Christopher K.

    2013-01-01

    With its 3,100 miles of tidal shoreline and low-lying rural and urban lands, “The Free State” is one of the most vulnerable to sea-level rise. Historically, Marylanders have long had to contend with rising water levels along its Chesapeake Bay and Atlantic Ocean and coastal bay shores. Shorelines eroded and low-relief lands and islands, some previously inhabited, were inundated. Prior to the 20th century, this was largely due to the slow sinking of the land since Earth’s crust is still adjusting to the melting of large masses of ice following the last glacial period. Over the 20th century, however, the rate of rise of the average level of tidal waters with respect to land, or relative sea-level rise, has increased, at least partially as a result of global warming. Moreover, the scientific evidence is compelling that Earth’s climate will continue to warm and its oceans will rise even more rapidly. Recognizing the scientific consensus around global climate change, the contribution of human activities to it, and the vulnerability of Maryland’s people, property, public investments, and natural resources, Governor Martin O’Malley established the Maryland Commission on Climate Change on April 20, 2007. The Commission produced a Plan of Action that included a comprehensive climate change impact assessment, a greenhouse gas reduction strategy, and strategies for reducing Maryland’s vulnerability to climate change. The Plan has led to landmark legislation to reduce the state’s greenhouse gas emissions and a variety of state policies designed to reduce energy consumption and promote adaptation to climate change.

  20. GHRSST Level 4 DMI_OI North Sea and Baltic Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

  1. Can salt marshes survive sea level rise ?

    Science.gov (United States)

    Tambroni, N.; Seminara, G.

    2008-12-01

    Stability of salt marshes is a very delicate issue depending on the subtle interplay among hydrodynamics, morphodynamics and ecology. In fact, the elevation of the marsh platform depends essentially on three effects: i) the production of soil associated with sediments resuspended by tidal currents and wind waves in the adjacent tidal flats, advected to the marsh and settling therein; ii) production of organic sediments by the salt marsh vegetation; iii) soil 'loss' driven by sea level rise and subsidence. In order to gain insight into the mechanics of the process, we consider a schematic configuration consisting of a salt marsh located at the landward end of a tidal channel connected at the upstream end with a tidal sea, under different scenarios of sea level rise. We extend the simple 1D model for the morphodynamic evolution of a tidal channel formulated by Lanzoni and Seminara (2002, Journal of Geophysical Research-Oceans, 107, C1) allowing for sediment resuspension in the channel and vegetation growth in the marsh using the depth dependent model of biomass productivity of Spartina proposed by Morris et al. (2002, Ecology, 83, pp. 2869 - 2877). We first focus on the case of a tide dominated salt marsh neglecting wind driven sediment resuspension in the shoal. Results show that the production of biomass plays a crucial role on salt marsh stability and, provided productivity is high enough, it may turn out to be sufficient to counteract the effects of sea level rise even in the absence of significant supply of mineral sediments. The additional effect of wind resuspension is then introduced. Note that the wind action is twofold: on one hand, it generates wind waves the amplitude of which is strongly dependent on shoal depth and wind fetch; on the other hand, it generates currents driven by the surface setup induced by the shear stress acting on the free surface. Here, each contribution is analysed separately. Results show that the values of bottom stress induced by

  2. GHRSST Level 4 ODYSSEA Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

  3. GHRSST Level 4 EUR Mediterranean Sea Regional Foundation Sea Surface Temperature Analysis (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily by Ifremer/CERSAT (France) using optimal...

  4. PERSPECTIVE: The tripping points of sea level rise

    Science.gov (United States)

    Hecht, Alan D.

    2009-12-01

    When President Nixon created the US Environmental Protection Agency (EPA) in 1970 he said the environment must be perceived as a single, interrelated system. We are nowhere close to achieving this vision. Jim Titus and his colleagues [1] highlight one example of where one set of regulations or permits may be in conflict with another and where regulations were crafted in the absence of understanding the cumulative impact of global warming. The issue here is how to deal with the impacts of climate change on sea level and the latter's impact on wetland polices, clean water regulations, and ecosystem services. The Titus paper could also be called `The tripping points of sea level rise'. Titus and his colleagues have looked at the impact of such sea level rise on the east coast of the United States. Adaptive responses include costly large- scale investment in shore protection (e.g. dikes, sand replenishment) and/or ecosystem migration (retreat), where coastal ecosystems move inland. Shore protection is limited by available funds, while ecosystem migrations are limited by available land use. The driving factor is the high probability of sea level rise due to climate change. Estimating sea level rise is difficult because of local land and coastal dynamics including rising or falling land areas. It is estimated that sea level could rise between 8 inches and 2 feet by the end of this century [2]. The extensive data analysis done by Titus et al of current land use is important because, as they observe, `property owners and land use agencies have generally not decided how they will respond to sea level rise, nor have they prepared maps delineating where shore protection and retreat are likely'. This is the first of two `tripping points', namely the need for adaptive planning for a pending environmental challenge that will create economic and environment conflict among land owners, federal and state agencies, and businesses. One way to address this gap in adaptive management

  5. Vertical ground motion and historical sea-level records in Dakar (Senegal)

    International Nuclear Information System (INIS)

    Le Cozannet, Gonéri; Raucoules, Daniel; Garcin, Manuel; Lavigne, Franck; Wöppelmann, Guy; Gravelle, Médéric; Da Sylva, Sylvestre; Meyssignac, Benoit

    2015-01-01

    With growing concerns regarding future impacts of sea-level in major coastal cities, the most accurate information is required regarding local sea-level changes with respect to the coast. Besides global and regional sea-level changes, local coastal vertical ground motions can substantially contribute to local changes in sea-level. In some cases, such ground motions can also limit the usefulness of tide-gauge records, which are a unique source of information to evaluate global sea-level changes before the altimetry era. Using satellite synthetic aperture radar interferometry, this study aims at characterizing vertical coastal ground motion in Dakar (Senegal), where a unique century-long record in Africa has been rediscovered. Given the limited number of available images, we use a stacking procedure to compute ground motion velocities in the line of sight over 1992–2010. Despite a complex geology and a rapid population growth and development, we show that the city as a whole is unaffected by differential ground motions larger than 1 mm year −1 . Only the northern part of the harbor displays subsidence patterns after 2000, probably as a consequence of land reclamation works. However, these ground motions do not affect the historical tide gauge. Our results highlight the value of the historical sea-level records of Dakar, which cover a 100 year time-span in a tropical oceanic region of Africa, where little data are available for past sea-level reconstructions. (letter)

  6. Present day sea level changes: observation and causes

    International Nuclear Information System (INIS)

    Lombard, A.

    2005-11-01

    Whereas sea level has changed little over the last 2000 years, it has risen at a rate of about 2 mm/year during the 20. century. This unexpected sea level rise has been attributed to the anthropogenic global warming, recorded over several decades. Sea level variations have been measured globally and precisely for about 12 years due to satellite altimeter missions Topex/Poseidon and Jason-1. These observations indicate a global mean sea level rise of about 3 mm/year since 1993, a value significantly larger than observed during previous decades. Recent observations have allowed us to quantify the various climatic factors contributing to observed sea level change: thermal expansion of sea water due to ocean warming, melting of mountain glaciers and ice sheets, and changes in the land water reservoirs. A water budget based on these new observations allows us to partly explain the observed sea level rise. In particular, we show that the thermal expansion explains only 25% of the secular sea level rise as recorded by tide-gauges over the last 50 years, while it contributes about 50% of sea level rise observed over the last decade. Meanwhile, recent studies show that glacier and ice sheet melting could contribute the equivalent of 1 mm/year in sea level rise over the last decade. In addition, the high regional variability of sea level trends revealed by satellite altimetry is mainly due to thermal expansion. There is also an important decadal spatio-temporal variability in the ocean thermal expansion over the last 50 years, which seems to be controlled by natural climate fluctuations. We question for the first time the link between the decadal fluctuations in the ocean thermal expansion and in the land reservoirs, and indeed their climatic contribution to sea level change. Finally a preliminary analysis of GRACE spatial gravimetric observations over the oceans allows us to estimate the seasonal variations in mean sea level due to ocean water mass balance variations

  7. Timescales for detecting a significant acceleration in sea level rise.

    Science.gov (United States)

    Haigh, Ivan D; Wahl, Thomas; Rohling, Eelco J; Price, René M; Pattiaratchi, Charitha B; Calafat, Francisco M; Dangendorf, Sönke

    2014-04-14

    There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that we have artificially extended to 2100. We find that the most important approach to earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual to multidecadal variability in sea level records.

  8. Potential of sea level rise impact on South China Sea: a preliminary ...

    African Journals Online (AJOL)

    The effect of the sea level rise was involved the existence of sea water intrusion and coastal erosion phenomenon in the coastal of Terengganu. This study aim to determine fluctuation of high and low tides of the South China Sea in their relation to water quality value of Marang and Paka Rivers as well as from wells ...

  9. Coastal wetlands, sea level, and the dimensions of geomorphic resilience

    Science.gov (United States)

    Phillips, Jonathan D.

    2018-03-01

    Geomorphic system resilience is often perceived as an intrinsic property of system structure and interactions but is also related to idiosyncratic place and history factors. The importance of geographical and historical circumstances makes it difficult to generate categorical statements about geomorphic resilience. However, network-based analyses of system structure can be used to determine the dynamical stability (= resilience) based on generally applicable relationships and to determine scenarios of stability or instability. These provide guidelines for assessing place and history factors to assess resilience. A model of coastal wetlands is analyzed, based on interactions among relative sea level, wetland surface elevation, hydroperiod, vegetation, and sedimentation. The system is generally (but not always) dynamically unstable and non-resilient. Because of gradients of environmental factors and patchy distributions of microtopography and vegetation, a coastal wetland landscape may have extensive local variations in stability/resilience and in the key relationships that trigger instabilities. This is illustrated by a case study where dynamically unstable fragmentation is found in two nearby coastal wetlands in North Carolina's Neuse River estuary-Otter Creek Mouth and Anderson Creek. Neither is keeping pace with relative sea level rise, and both show unstable state transitions within the wetland system; but locally stable relationships exist within the wetland systems.

  10. The social values at risk from sea-level rise

    International Nuclear Information System (INIS)

    Graham, Sonia; Barnett, Jon; Fincher, Ruth; Hurlimann, Anna; Mortreux, Colette; Waters, Elissa

    2013-01-01

    Analysis of the risks of sea-level rise favours conventionally measured metrics such as the area of land that may be subsumed, the numbers of properties at risk, and the capital values of assets at risk. Despite this, it is clear that there exist many less material but no less important values at risk from sea-level rise. This paper re-theorises these multifarious social values at risk from sea-level rise, by explaining their diverse nature, and grounding them in the everyday practices of people living in coastal places. It is informed by a review and analysis of research on social values from within the fields of social impact assessment, human geography, psychology, decision analysis, and climate change adaptation. From this we propose that it is the ‘lived values’ of coastal places that are most at risk from sea-level rise. We then offer a framework that groups these lived values into five types: those that are physiological in nature, and those that relate to issues of security, belonging, esteem, and self-actualisation. This framework of lived values at risk from sea-level rise can guide empirical research investigating the social impacts of sea-level rise, as well as the impacts of actions to adapt to sea-level rise. It also offers a basis for identifying the distribution of related social outcomes across populations exposed to sea-level rise or sea-level rise policies

  11. Past and future changes in extreme sea levels and waves

    Digital Repository Service at National Institute of Oceanography (India)

    Lawe, J.A.; Woodworth, P.L.; Knutson, T.; McDonald, R.E.; Mclnnes, K.L.; Woth, K.; Von Storch, H.; Wolf, J.; Swail, V.; Bernier, N.B.; Gulev, S.; Horsburgh, K.J.; Unnikrishnan, A.S.; Hunter, J.R.; Weisse, R.

    of Extreme Sea Level 11.3.1 An Introduction to Storms Both mid-latitude and tropical storms are associated with extremes of sea level. Storm surges are generated by low atmospheric pressure and intense winds over the ocean. The latter also cause high wave... timescales, extremes and mean-sea-level change are both major factors in determining coastal evolution including the development of coastal ecosystems. It will be seen below that, although it is difficult to determine how mean sea level has changed...

  12. The social values at risk from sea-level rise

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Sonia, E-mail: sonia.graham@unimelb.edu.au [Department of Resource Management and Geography, The University of Melbourne, 221 Bouverie St., Carlton, Victoria 3053 (Australia); Barnett, Jon, E-mail: jbarn@unimelb.edu.au [Department of Resource Management and Geography, The University of Melbourne, 221 Bouverie St., Carlton, Victoria 3053 (Australia); Fincher, Ruth, E-mail: r.fincher@unimelb.edu.au [Department of Resource Management and Geography, The University of Melbourne, 221 Bouverie St., Carlton, Victoria 3053 (Australia); Hurlimann, Anna, E-mail: anna.hurlimann@unimelb.edu.au [Faculty of Architecture, Building and Planning, The University of Melbourne, Architecture and Planning Building, Parkville, Victoria 3010 (Australia); Mortreux, Colette, E-mail: colettem@unimelb.edu.au [Department of Resource Management and Geography, The University of Melbourne, 221 Bouverie St., Carlton, Victoria 3053 (Australia); Waters, Elissa, E-mail: elissa.waters@unimelb.edu.au [Department of Resource Management and Geography, The University of Melbourne, 221 Bouverie St., Carlton, Victoria 3053 (Australia)

    2013-07-15

    Analysis of the risks of sea-level rise favours conventionally measured metrics such as the area of land that may be subsumed, the numbers of properties at risk, and the capital values of assets at risk. Despite this, it is clear that there exist many less material but no less important values at risk from sea-level rise. This paper re-theorises these multifarious social values at risk from sea-level rise, by explaining their diverse nature, and grounding them in the everyday practices of people living in coastal places. It is informed by a review and analysis of research on social values from within the fields of social impact assessment, human geography, psychology, decision analysis, and climate change adaptation. From this we propose that it is the ‘lived values’ of coastal places that are most at risk from sea-level rise. We then offer a framework that groups these lived values into five types: those that are physiological in nature, and those that relate to issues of security, belonging, esteem, and self-actualisation. This framework of lived values at risk from sea-level rise can guide empirical research investigating the social impacts of sea-level rise, as well as the impacts of actions to adapt to sea-level rise. It also offers a basis for identifying the distribution of related social outcomes across populations exposed to sea-level rise or sea-level rise policies.

  13. Barrier response to Holocene sea-level rise

    DEFF Research Database (Denmark)

    Pejrup, Morten; Andersen, Thorbjørn Joest; Johannessen, Peter N

    Normally it is believed that sea-level rise causes coastal barrier retreat. However, sea-level is only one of the parameters determining the long term coastal development of barrier coasts. Sediment supply is an equally important determinant and may overshadow the effects of sea-level rise....... Conceptually this has been known for a long time but for the first time we can show the relative effect of these two parameters. We have studied three neighboring barrier islands in the Wadden Sea, and described their 3D morphological evolution during the last 8000 years. It appears that the barrier islands...... a much stronger component of sea-level control. The distance between the islands is only 50 km, and therefore our study shows that prediction of barrier development during a period of rising sea level may be more complicated than formerly believed....

  14. The rise of sea level. To understand and to anticipate

    International Nuclear Information System (INIS)

    2013-03-01

    By proposing and briefly commenting graphs and drawings, this publication propose brief presentations of the main issues related to sea level rise: global warming and climate disturbance, description of the phenomenon of sea level rise (difference between sea ice and ground ice, melting of glaciers), increase of sea level rise during the twentieth century, territories at risk (examples of Greenland, Tuvalu, Shanghai), acceleration of ice melting during the twenty first century with many coastal areas at risk, already noticed and possible future impacts in France (glaciers runoff, threatened coasts, example of the Xynthia tempest), how to be united and to anticipate (a threat for millions of people, adaptation to sea level rise, limitation of global warming to limit sea level rise)

  15. A scaling approach to project regional sea level rise and its uncertainties

    Directory of Open Access Journals (Sweden)

    M. Perrette

    2013-01-01

    Full Text Available Climate change causes global mean sea level to rise due to thermal expansion of seawater and loss of land ice from mountain glaciers, ice caps and ice sheets. Locally, sea level can strongly deviate from the global mean rise due to changes in wind and ocean currents. In addition, gravitational adjustments redistribute seawater away from shrinking ice masses. However, the land ice contribution to sea level rise (SLR remains very challenging to model, and comprehensive regional sea level projections, which include appropriate gravitational adjustments, are still a nascent field (Katsman et al., 2011; Slangen et al., 2011. Here, we present an alternative approach to derive regional sea level changes for a range of emission and land ice melt scenarios, combining probabilistic forecasts of a simple climate model (MAGICC6 with the new CMIP5 general circulation models. The contribution from ice sheets varies considerably depending on the assumptions for the ice sheet projections, and thus represents sizeable uncertainties for future sea level rise. However, several consistent and robust patterns emerge from our analysis: at low latitudes, especially in the Indian Ocean and Western Pacific, sea level will likely rise more than the global mean (mostly by 10–20%. Around the northeastern Atlantic and the northeastern Pacific coasts, sea level will rise less than the global average or, in some rare cases, even fall. In the northwestern Atlantic, along the American coast, a strong dynamic sea level rise is counteracted by gravitational depression due to Greenland ice melt; whether sea level will be above- or below-average will depend on the relative contribution of these two factors. Our regional sea level projections and the diagnosed uncertainties provide an improved basis for coastal impact analysis and infrastructure planning for adaptation to climate change.

  16. Projecting Future Sea Level Rise for Water Resources Planning in California

    Science.gov (United States)

    Anderson, J.; Kao, K.; Chung, F.

    2008-12-01

    Sea level rise is one of the major concerns for the management of California's water resources. Higher water levels and salinity intrusion into the Sacramento-San Joaquin Delta could affect water supplies, water quality, levee stability, and aquatic and terrestrial flora and fauna species and their habitat. Over the 20th century, sea levels near San Francisco Bay increased by over 0.6ft. Some tidal gauge and satellite data indicate that rates of sea level rise are accelerating. Sea levels are expected to continue to rise due to increasing air temperatures causing thermal expansion of the ocean and melting of land-based ice such as ice on Greenland and in southeastern Alaska. For water planners, two related questions are raised on the uncertainty of future sea levels. First, what is the expected sea level at a specific point in time in the future, e.g., what is the expected sea level in 2050? Second, what is the expected point of time in the future when sea levels will exceed a certain height, e.g., what is the expected range of time when the sea level rises by one foot? To address these two types of questions, two factors are considered: (1) long term sea level rise trend, and (2) local extreme sea level fluctuations. A two-step approach will be used to develop sea level rise projection guidelines for decision making that takes both of these factors into account. The first step is developing global sea level rise probability distributions for the long term trends. The second step will extend the approach to take into account the effects of local astronomical tides, changes in atmospheric pressure, wind stress, floods, and the El Niño/Southern Oscillation. In this paper, the development of the first step approach is presented. To project the long term sea level rise trend, one option is to extend the current rate of sea level rise into the future. However, since recent data indicate rates of sea level rise are accelerating, methods for estimating sea level rise

  17. XXI century projections of wind-wave conditions and sea-level rise in the Black sea

    Science.gov (United States)

    Polonsky, A.; Garmashov, A.; Fomin, V.; Valchev, N.; Trifonova, E.

    2012-04-01

    generates the high waves in the S-E Black sea. The climate projections show that the frequency of such atmospheric pattern will not principally increase. The recent probability of the extreme wave height (exceeding 8 to10 m) in the S-W Black sea (~1 occurrence per 10 years) will not be much worse in XXI century. Similar conclusion is true for the storm surges along the Bulgarian coastline. Expected sea level rise in the Black sea basin for XXI century due to regional climate changes is about 2 mm per year (±50%). However, some Black sea subregions (such as Odessa and Varna bay) are characterized by fivefold sea level rise because of the local land subsidence. So, this geomorphologic effect is the most dangerous local consequence for the sustainable development and management of the coastal zone in such subregions. This study was supported by EC project "THESEUS".

  18. Surging Seas Risk Finder: A Tool for Local-Scale Flood Risk Assessments in Coastal Cities

    Science.gov (United States)

    Kulp, S. A.; Strauss, B.

    2015-12-01

    Local decision makers in coastal cities require accurate, accessible, and thorough assessments of flood exposure risk within their individual municipality, in their efforts to mitigate against damage due to future sea level rise. To fill this need, we have developed Climate Central's Surging Seas Risk Finder, an interactive data toolkit which presents our sea level rise and storm surge analysis for every coastal town, city, county, and state within the USA. Using this tool, policy makers can easily zoom in on their local place of interest to receive a detailed flood risk assessment, which synthesizes a wide range of features including total population, socially vulnerable population, housing, property value, road miles, power plants, schools, hospitals, and many other critical facilities. Risk Finder can also be used to identify specific points of interest in danger of exposure at different flood levels. Additionally, this tool provides localized storm surge probabilities and sea level rise projections at tidal gauges along the coast, so that users can quickly understand the risk of flooding in their area over the coming decades.

  19. Understanding extreme sea levels for coastal impact and adaptation analysis

    Science.gov (United States)

    Wahl, T.; Haigh, I. D.; Nicholls, R. J.; Arns, A.; Hinkel, J.; Dangendorf, S.; Slangen, A.

    2016-12-01

    Coastal impact and adaptation assessments require detailed knowledge on extreme sea levels, because increasing damage due to extreme events, such as storm surges and tropical cyclones, is one of the major consequences of sea level rise and climate change. In fact, the IPCC has highlighted in its AR4 report that "societal impacts of sea level change primarily occur via the extreme levels rather than as a direct consequence of mean sea level changes". Over the last few decades, substantial research efforts have been directed towards improved understanding of past and future mean sea level; different scenarios were developed with process-based or semi-empirical models and used for coastal impact assessments at various spatial scales to guide coastal management and adaptation efforts. The uncertainties in future sea level rise are typically accounted for by analyzing the impacts associated with a range of scenarios leading to a vertical displacement of the distribution of extreme sea-levels. And indeed most regional and global studies find little or no evidence for changes in storminess with climate change, although there is still low confidence in the results. However, and much more importantly, there is still a limited understanding of present-day extreme sea-levels which is largely ignored in most impact and adaptation analyses. The two key uncertainties stem from: (1) numerical models that are used to generate long time series of extreme sea-levels. The bias of these models varies spatially and can reach values much larger than the expected sea level rise; but it can be accounted for in most regions making use of in-situ measurements; (2) Statistical models used for determining present-day extreme sea-level exceedance probabilities. There is no universally accepted approach to obtain such values for flood risk assessments and while substantial research has explored inter-model uncertainties for mean sea level, we explore here, for the first time, inter

  20. Late Quaternary sea level and environmental changes from relic ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Keywords. Late Quaternary sea level; western margin of India; subsidence; uplift; depositional environment. ...... sea level rise by about 80m (between 12,000 and. 7,000 yr BP) or, .... from the Florida Keys; Palaentology 28 189–206. Carballo ...

  1. Sea level oscillations over minute timescales: a global perspective

    Science.gov (United States)

    Vilibic, Ivica; Sepic, Jadranka

    2016-04-01

    Sea level oscillations occurring over minutes to a few hours are an important contributor to sea level extremes, and a knowledge on their behaviour is essential for proper quantification of coastal marine hazards. Tsunamis, meteotsunamis, infra-gravity waves and harbour oscillations may even dominate sea level extremes in certain areas and thus pose a great danger for humans and coastal infrastructure. Aside for tsunamis, which are, due to their enormous impact to the coastlines, a well-researched phenomena, the importance of other high-frequency oscillations to the sea level extremes is still underrated, as no systematic long-term measurements have been carried out at a minute timescales. Recently, Intergovernmental Oceanographic Commission (IOC) established Sea Level Monitoring Facility portal (http://www.ioc-sealevelmonitoring.org), making 1-min sea level data publicly available for several hundred tide gauge sites in the World Ocean. Thereafter, a global assessment of oscillations over tsunami timescales become possible; however, the portal contains raw sea level data only, being unchecked for spikes, shifts, drifts and other malfunctions of instruments. We present a quality assessment of these data, estimates of sea level variances and contributions of high-frequency processes to the extremes throughout the World Ocean. This is accompanied with assessment of atmospheric conditions and processes which generate intense high-frequency oscillations.

  2. Separating decadal global water cycle variability from sea level rise.

    Science.gov (United States)

    Hamlington, B D; Reager, J T; Lo, M-H; Karnauskas, K B; Leben, R R

    2017-04-20

    Under a warming climate, amplification of the water cycle and changes in precipitation patterns over land are expected to occur, subsequently impacting the terrestrial water balance. On global scales, such changes in terrestrial water storage (TWS) will be reflected in the water contained in the ocean and can manifest as global sea level variations. Naturally occurring climate-driven TWS variability can temporarily obscure the long-term trend in sea level rise, in addition to modulating the impacts of sea level rise through natural periodic undulation in regional and global sea level. The internal variability of the global water cycle, therefore, confounds both the detection and attribution of sea level rise. Here, we use a suite of observations to quantify and map the contribution of TWS variability to sea level variability on decadal timescales. In particular, we find that decadal sea level variability centered in the Pacific Ocean is closely tied to low frequency variability of TWS in key areas across the globe. The unambiguous identification and clean separation of this component of variability is the missing step in uncovering the anthropogenic trend in sea level and understanding the potential for low-frequency modulation of future TWS impacts including flooding and drought.

  3. Projecting twenty-first century regional sea-level changes

    NARCIS (Netherlands)

    Slangen, A.B.A.; Carson, M.; Katsman, C.A.; van de Wal, R.S.W.; Köhl, A.; Vermeersen, L.L.A.; Stammer, D.

    2014-01-01

    We present regional sea-level projections and associated uncertainty estimates for the end of the 21 (st) century. We show regional projections of sea-level change resulting from changing ocean circulation, increased heat uptake and atmospheric pressure in CMIP5 climate models. These are combined

  4. Changes in extreme regional sea level under global warming

    NARCIS (Netherlands)

    Brunnabend, S. E.; Dijkstra, H. A.; Kliphuis, Michael; Bal, Henri E.; Seinstra, Frank J.; van Werkhoven, Ben; Maassen, J.; van Meersbergen, Maarten

    2017-01-01

    An important contribution to future changes in regional sea level extremes is due to the changes in intrinsic ocean variability, in particular ocean eddies. Here, we study a scenario of future dynamic sea level (DSL) extremes using a high-resolution version of the Parallel Ocean Program and

  5. Diurnal variations of serum erythropoietin at sea level and altitude

    DEFF Research Database (Denmark)

    Klausen, T; Poulsen, T D; Fogh-Andersen, N

    1996-01-01

    in 2, 3 diphosphoglycerate. After 64 h at altitude, six of the nine subjects had down-regulated their serum-EPO concentrations so that median values were three times above those at sea level. These six subjects had significant diurnal variations of serum-EPO concentration at sea level; the nadir...

  6. Sea-level Variation Along the Suez Canal

    Science.gov (United States)

    Eid, F. M.; Sharaf El-Din, S. H.; Alam El-Din, K. A.

    1997-05-01

    The variation of sea level at 11 stations distributed along the Suez Canal was studied during the period from 1980 to 1986. The ranges of variation in daily mean sea level at Port Said and Port Tawfik are about 60 and 120 cm, respectively. The minimum range of daily variation is at Kantara (47 cm). The fluctuations of the monthly mean sea level between the two ends of the Suez Canal vary from one season to another. From July to December, the sea level at Port Said is higher than that at Port Tawfik, with the maximum difference (10·5 cm) in September. During the rest of the year, the mean sea level at Port Tawfik is higher than that at Port Said, with the maximum difference (31·5 cm) in March. The long-term variations of the annual mean sea level at both Port Said and Port Tawfik for the period from 1923 to 1986 showed a positive trend. The sea level at Port Said increased by about 27·8 cm century -1while it increased by only 9·1 cm century -1at Port Tawfik. This indicates that the difference between sea level at Port Said and Port Tawfik has decreased with time.

  7. Integrative study of the mean sea level and its components

    CERN Document Server

    Champollion, Nicolas; Paul, Frank; Benveniste, Jérôme

    2017-01-01

    This volume presents the most recent results of global mean sea level variations over the satellite altimetry era (starting in the early 1990s) and associated contributions, such as glaciers and ice sheets mass loss, ocean thermal expansion, and land water storage changes. Sea level is one of the best indicators of global climate changes as it integrates the response of several components of the climate system to external forcing factors (including anthropogenic forcing) and internal climate variability. Providing long, accurate records of the sea level at global and regional scales and of the various components causing sea level changes is of crucial importance to improve our understanding of climate processes at work and to validate the climate models used for future projections. The Climate Change Initiative project of the European Space Agency has provided a first attempt to produce consistent and continuous space-based records for several climate parameters observable from space, among them sea level. Th...

  8. ACCELERATION OF SEA LEVEL RISE OVER MALAYSIAN SEAS FROM SATELLITE ALTIMETER

    Directory of Open Access Journals (Sweden)

    A. I. A. Hamid

    2016-09-01

    Full Text Available Sea level rise becomes our concern nowadays as a result of variously contribution of climate change that cause by the anthropogenic effects. Global sea levels have been rising through the past century and are projected to rise at an accelerated rate throughout the 21st century. Due to this change, sea level is now constantly rising and eventually will threaten many low-lying and unprotected coastal areas in many ways. This paper is proposing a significant effort to quantify the sea level trend over Malaysian seas based on the combination of multi-mission satellite altimeters over a period of 23 years. Eight altimeter missions are used to derive the absolute sea level from Radar Altimeter Database System (RADS. Data verification is then carried out to verify the satellite derived sea level rise data with tidal data. Eight selected tide gauge stations from Peninsular Malaysia, Sabah and Sarawak are chosen for this data verification. The pattern and correlation of both measurements of sea level anomalies (SLA are evaluated over the same period in each area in order to produce comparable results. Afterwards, the time series of the sea level trend is quantified using robust fit regression analysis. The findings clearly show that the absolute sea level trend is rising and varying over the Malaysian seas with the rate of sea level varies and gradually increase from east to west of Malaysia. Highly confident and correlation level of the 23 years measurement data with an astonishing root mean square difference permits the absolute sea level trend of the Malaysian seas has raised at the rate 3.14 ± 0.12 mm yr-1 to 4.81 ± 0.15 mm yr-1 for the chosen sub-areas, with an overall mean of 4.09 ± 0.12 mm yr-1. This study hopefully offers a beneficial sea level information to be applied in a wide range of related environmental and climatology issue such as flood and global warming.

  9. Acceleration of Sea Level Rise Over Malaysian Seas from Satellite Altimeter

    Science.gov (United States)

    Hamid, A. I. A.; Din, A. H. M.; Khalid, N. F.; Omar, K. M.

    2016-09-01

    Sea level rise becomes our concern nowadays as a result of variously contribution of climate change that cause by the anthropogenic effects. Global sea levels have been rising through the past century and are projected to rise at an accelerated rate throughout the 21st century. Due to this change, sea level is now constantly rising and eventually will threaten many low-lying and unprotected coastal areas in many ways. This paper is proposing a significant effort to quantify the sea level trend over Malaysian seas based on the combination of multi-mission satellite altimeters over a period of 23 years. Eight altimeter missions are used to derive the absolute sea level from Radar Altimeter Database System (RADS). Data verification is then carried out to verify the satellite derived sea level rise data with tidal data. Eight selected tide gauge stations from Peninsular Malaysia, Sabah and Sarawak are chosen for this data verification. The pattern and correlation of both measurements of sea level anomalies (SLA) are evaluated over the same period in each area in order to produce comparable results. Afterwards, the time series of the sea level trend is quantified using robust fit regression analysis. The findings clearly show that the absolute sea level trend is rising and varying over the Malaysian seas with the rate of sea level varies and gradually increase from east to west of Malaysia. Highly confident and correlation level of the 23 years measurement data with an astonishing root mean square difference permits the absolute sea level trend of the Malaysian seas has raised at the rate 3.14 ± 0.12 mm yr-1 to 4.81 ± 0.15 mm yr-1 for the chosen sub-areas, with an overall mean of 4.09 ± 0.12 mm yr-1. This study hopefully offers a beneficial sea level information to be applied in a wide range of related environmental and climatology issue such as flood and global warming.

  10. The land-ice contribution to 21st-century dynamic sea level rise

    Science.gov (United States)

    Howard, T.; Ridley, J.; Pardaens, A. K.; Hurkmans, R. T. W. L.; Payne, A. J.; Giesen, R. H.; Lowe, J. A.; Bamber, J. L.; Edwards, T. L.; Oerlemans, J.

    2014-06-01

    Climate change has the potential to influence global mean sea level through a number of processes including (but not limited to) thermal expansion of the oceans and enhanced land ice melt. In addition to their contribution to global mean sea level change, these two processes (among others) lead to local departures from the global mean sea level change, through a number of mechanisms including the effect on spatial variations in the change of water density and transport, usually termed dynamic sea level changes. In this study, we focus on the component of dynamic sea level change that might be given by additional freshwater inflow to the ocean under scenarios of 21st-century land-based ice melt. We present regional patterns of dynamic sea level change given by a global-coupled atmosphere-ocean climate model forced by spatially and temporally varying projected ice-melt fluxes from three sources: the Antarctic ice sheet, the Greenland Ice Sheet and small glaciers and ice caps. The largest ice melt flux we consider is equivalent to almost 0.7 m of global mean sea level rise over the 21st century. The temporal evolution of the dynamic sea level changes, in the presence of considerable variations in the ice melt flux, is also analysed. We find that the dynamic sea level change associated with the ice melt is small, with the largest changes occurring in the North Atlantic amounting to 3 cm above the global mean rise. Furthermore, the dynamic sea level change associated with the ice melt is similar regardless of whether the simulated ice fluxes are applied to a simulation with fixed CO2 or under a business-as-usual greenhouse gas warming scenario of increasing CO2.

  11. Evaluating model simulations of 20th century sea-level rise. Part 1: global mean sea-level change

    NARCIS (Netherlands)

    Slangen, A.B.A.; Meyssignac, B.; Agosta, C.; Champollion, N.; Church, J.A.; Fettweis, X.; Ligtenberg, S.R.M.; Marzeion, B.; Melet, A.; Palmer, M.D.; Richter, K.; Roberts, C.D.; Spada, G.

    2017-01-01

    Sea level change is one of the major consequences of climate change and is projected to affect coastal communities around the world. Here, global mean sea level (GMSL) change estimated by 12 climate models from phase 5 of the World Climate Research Programme’s Climate Model Intercomparison Project

  12. Sea level rise and variability around Peninsular Malaysia

    Science.gov (United States)

    Tkalich, Pavel; Luu, Quang-Hung; Tay, Tze-Wei

    2014-05-01

    Peninsular Malaysia is bounded from the west by Malacca Strait and the Andaman Sea, both connected to the Indian Ocean, and from the east by South China Sea being largest marginal sea in the Pacific Basin. As a result, sea level along Peninsular Malaysia coast is assumed to be governed by various regional phenomena associated with the adjacent parts of the Indian and Pacific Oceans. At annual scale, sea level anomalies (SLAs) are generated by the Asian monsoon; interannual sea level variability is determined by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD); whilst long term sea level trend is coordinated by the global climate change. To quantify the relative impacts of these multi-scale phenomena on sea level trend and variability surrounding the Peninsular Malaysia, long-term tide gauge record and satellite altimetry are used. During 1984-2011, relative sea level rise (SLR) rates in waters of Malacca Strait and eastern Peninsular Malaysia are found to be 2.4 ± 0.8 mm/yr and 2.7 ± 0.6 mm/yr, respectively. Discounting for their vertical land movements (0.8 ± 2.6 mm/yr and 0.9 ± 2.2 mm/yr, respectively), their pure SLR rates are 1.6 ± 3.4 mm/yr and 1.8 ± 2.8 mm/yr, respectively, which are lower than the global tendency. At interannual scale, ENSO affects sea level over the Malaysian east coast in the range of ± 5 cm with very high correlation coefficient. Meanwhile, IOD modulates sea level anomalies in the Malacca Strait in the range of ± 2 cm with high correlation coefficient. Interannual regional sea level drops are associated with El Niño events and positive phases of the IOD index; while the rises are correlated with La Niña episodes and the negative periods of the IOD index. Seasonally, SLAs are mainly monsoon-driven, in the order of 10-25 cm. Geographically, sea level responds differently to the monsoon: two cycles per year are observed in the Malacca Strait, presumably due to South Asian - Indian Monsoon; while single

  13. Simultaneous estimation of lithospheric uplift rates and absolute sea level change in southwest Scandinavia from inversion of sea level data

    DEFF Research Database (Denmark)

    Nielsen, Lars; Hansen, Jens Morten; Hede, Mikkel Ulfeldt

    2014-01-01

    the relative sea level data. Similar independent data do not exist for ancient times. The purpose of this study is to test two simple inversion approaches for simultaneous estimation of lithospheric uplift rates and absolute sea level change rates for ancient times in areas where a dense coverage of relative...... sea level data exists and well-constrained average lithospheric movement values are known from, for example glacial isostatic adjustment (GIA) models. The inversion approaches are tested and used for simultaneous estimation of lithospheric uplift rates and absolute sea level change rates in southwest...... Scandinavia from modern relative sea level data series that cover the period from 1900 to 2000. In both approaches, a priori information is required to solve the inverse problem. A priori information about the average vertical lithospheric movement in the area of interest is critical for the quality...

  14. Sea Level Data Archaeology for the Global Sea Level Observing System (GLOSS)

    Science.gov (United States)

    Bradshaw, Elizabeth; Matthews, Andy; Rickards, Lesley; Jevrejeva, Svetlana

    2015-04-01

    The Global Sea Level Observing System (GLOSS) was set up in 1985 to collect long term tide gauge observations and has carried out a number of data archaeology activities over the past decade, including sending member organisations questionnaires to report on their repositories. The GLOSS Group of Experts (GLOSS GE) is looking to future developments in sea level data archaeology and will provide its user community with guidance on finding, digitising, quality controlling and distributing historic records. Many records may not be held in organisational archives and may instead by in national libraries, archives and other collections. GLOSS will promote a Citizen Science approach to discovering long term records by providing tools for volunteers to report data. Tide gauge data come in two different formats, charts and hand-written ledgers. Charts are paper analogue records generated by the mechanical instrument driving a pen trace. Several GLOSS members have developed software to automatically digitise these charts and the various methods were reported in a paper on automated techniques for the digitization of archived mareograms, delivered to the GLOSS GE 13th meeting. GLOSS is creating a repository of software for scanning analogue charts. NUNIEAU is the only publically available software for digitising tide gauge charts but other organisations have developed their own tide gauge digitising software that is available internally. There are several other freely available software packages that convert image data to numerical values. GLOSS could coordinate a comparison study of the various different digitising software programs by: Sending the same charts to each organisation and asking everyone to digitise them using their own procedures Comparing the digitised data Providing recommendations to the GLOSS community The other major form of analogue sea level data is handwritten ledgers, which are usually observations of high and low waters, but sometimes contain higher

  15. Arctic Sea Level During the Satellite Altimetry Era

    DEFF Research Database (Denmark)

    Carret, A.; Johannessen, J. A.; Andersen, Ole Baltazar

    2017-01-01

    Results of the sea-level budget in the high latitudes (up to 80°N) and the Arctic Ocean during the satellite altimetry era. We investigate the closure of the sea-level budget since 2002 using two altimetry sea-level datasets based on the Envisat waveform retracking: temperature and salinity data....... However, in terms of regional average over the region ranging from 66°N to 80°N, the steric component contributes little to the observed sea-level trend, suggesting a dominant mass contribution in the Arctic region. This is confirmed by GRACE-based ocean mass time series that agree well with the altimetry......-based sea-level time series. Direct estimate of the mass component is not possible prior to GRACE. Thus, we estimated the mass contribution from the difference between the altimetry-based sea level and the steric component. We also investigate the coastal sea level with tide gauge records. Twenty coupled...

  16. Sea level change: lessons from the geologic record

    Science.gov (United States)

    ,

    1995-01-01

    Rising sea level is potentially one of the most serious impacts of climatic change. Even a small sea level rise would have serious economic consequences because it would cause extensive damage to the world's coastal regions. Sea level can rise in the future because the ocean surface can expand due to warming and because polar ice sheets and mountain glaciers can melt, increasing the ocean's volume of water. Today, ice caps on Antarctica and Greenland contain 91 and 8 percent of the world's ice, respectively. The world's mountain glaciers together contain only about 1 percent. Melting all this ice would raise sea level about 80 meters. Although this extreme scenario is not expected, geologists know that sea level can rise and fall rapidly due to changing volume of ice on continents. For example, during the last ice age, about 18,000 years ago, continental ice sheets contained more than double the modem volume of ice. As ice sheets melted, sea level rose 2 to 3 meters per century, and possibly faster during certain times. During periods in which global climate was very warm, polar ice was reduced and sea level was higher than today.

  17. Indo-Pacific sea level variability during recent decades

    Science.gov (United States)

    Yamanaka, G.; Tsujino, H.; Nakano, H.; Urakawa, S. L.; Sakamoto, K.

    2016-12-01

    Decadal variability of sea level in the Indo-Pacific region is investigated using a historical OGCM simulation. The OGCM driven by the atmospheric forcing removing long-term trends clearly exhibits decadal sea level variability in the Pacific Ocean, which is associated with eastern tropical Pacific thermal anomalies. During the period of 1977-1987, the sea level anomalies are positive in the eastern equatorial Pacific and show deviations from a north-south symmetric distribution, with strongly negative anomalies in the western tropical South Pacific. During the period of 1996-2006, in contrast, the sea level anomalies are negative in the eastern equatorial Pacific and show a nearly north-south symmetric pattern, with positive anomalies in both hemispheres. Concurrently, sea level anomalies in the south-eastern Indian Ocean vary with those in the western tropical Pacific. These sea level variations are closely related to large-scale wind fields. Indo-Pacific sea level distributions are basically determined by wind anomalies over the equatorial region as well as wind stress curl anomalies over the off-equatorial region.

  18. Present-day sea level rise: a synthesis

    International Nuclear Information System (INIS)

    Cazenave, A.; Llovel, W.; Lombard, A.

    2008-01-01

    Measuring sea level change and understanding its causes have improved considerably in the recent years, essentially because new in situ and remote sensing data sets have become available. Here we report on the current knowledge of present-day sea level change. We briefly present observational results on sea level change from satellite altimetry since 1993 and tide gauges for the past century. We next discuss recent progress made in quantifying the processes causing sea level change on time scales ranging from years to decades, i.e., thermal expansion, land ice mass loss and land water storage change. For the 1993-2003 decade, the sum of climate-related contributions agree well (within the error bars) with the altimetry-based sea level, half of the observed rate of rise being due to ocean thermal expansion, land ice plus land waters explaining the other half. Since about 2003, thermal expansion increase has stopped, whereas the sea level continues to rise, although at a reduced rate compared to the previous decade (2.5 mm/yr versus 3.1 mm/yr). Recent increases in glacier melting and ice mass loss from the ice sheets appear able to account alone for the rise in sea level reported over the last five years. (authors)

  19. Precise mean sea level measurements using the Global Positioning System

    Science.gov (United States)

    Kelecy, Thomas M.; Born, George H.; Parke, Michael E.; Rocken, Christian

    1994-01-01

    This paper describes the results of a sea level measurement test conducted off La Jolla, California, in November of 1991. The purpose of this test was to determine accurate sea level measurements using a Global Positioning System (GPS) equipped buoy. These measurements were intended to be used as the sea level component for calibration of the ERS 1 satellite altimeter. Measurements were collected on November 25 and 28 when the ERS 1 satellite overflew the calibration area. Two different types of buoys were used. A waverider design was used on November 25 and a spar design on November 28. This provided the opportunity to examine how dynamic effects of the measurement platform might affect the sea level accuracy. The two buoys were deployed at locations approximately 1.2 km apart and about 15 km west of a reference GPS receiver located on the rooftop of the Institute of Geophysics and Planetary Physics at the Scripps Institute of Oceanography. GPS solutions were computed for 45 minutes on each day and used to produce two sea level time series. An estimate of the mean sea level at both locations was computed by subtracting tide gage data collected at the Scripps Pier from the GPS-determined sea level measurements and then filtering out the high-frequency components due to waves and buoy dynamics. In both cases the GPS estimate differed from Rapp's mean altimetric surface by 0.06 m. Thus, the gradient in the GPS measurements matched the gradient in Rapp's surface. These results suggest that accurate sea level can be determined using GPS on widely differing platforms as long as care is taken to determine the height of the GPS antenna phase center above water level. Application areas include measurement of absolute sea level, of temporal variations in sea level, and of sea level gradients (dominantly the geoid). Specific applications would include ocean altimeter calibration, monitoring of sea level in remote regions, and regional experiments requiring spatial and

  20. Anthropogenic sea level rise and adaptation in the Yangtze estuary

    Science.gov (United States)

    Cheng, H.; Chen, J.; Chen, Z.; Ruan, R.; Xu, G.; Zeng, G.; Zhu, J.; Dai, Z.; Gu, S.; Zhang, X.; Wang, H.

    2016-02-01

    Sea level rise is a major projected threat of climate change. There are regional variations in sea level changes, depending on both naturally the tectonic subsidence, geomorphology, naturally changing river inputs and anthropogenic driven forces as artificial reservoir water impoundment within the watershed and urban land subsidence driven by ground water depletion in the river delta. Little is known on regional sea level fall in response to the channel erosion due to the sediment discharge decline by reservoir interception in the upstream watershed, and water level rise driven by anthropogenic measures as the land reclamation, deep waterway regulation and fresh water reservoir construction to the sea level change in estuaries. Changing coastal cities are situated in the delta regions expected to be threatened in various degrees. Shanghai belongs to those cities. Here we show that the anthropogenic driven sea level rise in the Yangtze estuary from the point of view of the continuous hydrodynamic system consisted of river catchment, estuary and coastal sea. Land subsidence is cited as 4 mm/a (2011-2030). Scour depth of the estuarine channel by upstream engineering as Three Gauge Dam is estimated at 2-10 cm (2011-2030). The rise of water level by deep waterway and land reclamation is estimated at 8-10 cm (2011-2030). The relative sea level rise will be speculated about 10 -16 cm (2011-2030), which these anthropogenic sea level changes will be imposed into the absolute sea level rise 2 mm/a and tectonic subsidence 1 mm/a measured in 1990s. The action guideline to the sea level rise strategy in the Shanghai city have been proposed to the Shanghai government as (1) recent actions (2012-2015) to upgrade the city water supply and drainage engineering and protective engineering; (2) interim actions (2016-2020) to improve sea level monitoring and early warning system, and then the special, city, regional planning considering sea level rise; (3) long term actions (2021

  1. THRESHOLD DETERMINATION FOR LOCAL INSTANTANEOUS SEA SURFACE HEIGHT DERIVATION WITH ICEBRIDGE DATA IN BEAUFORT SEA

    Directory of Open Access Journals (Sweden)

    C. Zhu

    2018-05-01

    Full Text Available The NASA Operation IceBridge (OIB mission is the largest program in the Earth’s polar remote sensing science observation project currently, initiated in 2009, which collects airborne remote sensing measurements to bridge the gap between NASA’s ICESat and the upcoming ICESat-2 mission. This paper develop an improved method that optimizing the selection method of Digital Mapping System (DMS image and using the optimal threshold obtained by experiments in Beaufort Sea to calculate the local instantaneous sea surface height in this area. The optimal threshold determined by comparing manual selection with the lowest (Airborne Topographic Mapper ATM L1B elevation threshold of 2 %, 1 %, 0.5 %, 0.2 %, 0.1 % and 0.05 % in A, B, C sections, the mean of mean difference are 0.166 m, 0.124 m, 0.083 m, 0.018 m, 0.002 m and −0.034 m. Our study shows the lowest L1B data of 0.1 % is the optimal threshold. The optimal threshold and manual selections are also used to calculate the instantaneous sea surface height over images with leads, we find that improved methods has closer agreement with those from L1B manual selections. For these images without leads, the local instantaneous sea surface height estimated by using the linear equations between distance and sea surface height calculated over images with leads.

  2. Multi-Level Secure Local Area Network

    OpenAIRE

    Naval Postgraduate School (U.S.); Center for Information Systems Studies Security and Research (CISR)

    2011-01-01

    Multi-Level Secure Local Area Network is a cost effective, multi-level, easy to use office environment leveraging existing high assurance technology. The Department of Defense and U.S. Government have an identified need to securely share information classified at differing security levels. Because there exist no commercial solutions to this problem, NPS is developing a MLS LAN. The MLS LAN extends high assurance capabilities of an evaluated multi-level secure system to commercial personal com...

  3. Sea-level variability over five glacial cycles.

    Science.gov (United States)

    Grant, K M; Rohling, E J; Ramsey, C Bronk; Cheng, H; Edwards, R L; Florindo, F; Heslop, D; Marra, F; Roberts, A P; Tamisiea, M E; Williams, F

    2014-09-25

    Research on global ice-volume changes during Pleistocene glacial cycles is hindered by a lack of detailed sea-level records for time intervals older than the last interglacial. Here we present the first robustly dated, continuous and highly resolved records of Red Sea sea level and rates of sea-level change over the last 500,000 years, based on tight synchronization to an Asian monsoon record. We observe maximum 'natural' (pre-anthropogenic forcing) sea-level rise rates below 2 m per century following periods with up to twice present-day ice volumes, and substantially higher rise rates for greater ice volumes. We also find that maximum sea-level rise rates were attained within 2 kyr of the onset of deglaciations, for 85% of such events. Finally, multivariate regressions of orbital parameters, sea-level and monsoon records suggest that major meltwater pulses account for millennial-scale variability and insolation-lagged responses in Asian monsoon records.

  4. Sea level trend and variability around Peninsular Malaysia

    Science.gov (United States)

    Luu, Q. H.; Tkalich, P.; Tay, T. W.

    2015-08-01

    Sea level rise due to climate change is non-uniform globally, necessitating regional estimates. Peninsular Malaysia is located in the middle of Southeast Asia, bounded from the west by the Malacca Strait, from the east by the South China Sea (SCS), and from the south by the Singapore Strait. The sea level along the peninsula may be influenced by various regional phenomena native to the adjacent parts of the Indian and Pacific oceans. To examine the variability and trend of sea level around the peninsula, tide gauge records and satellite altimetry are analyzed taking into account vertical land movements (VLMs). At annual scale, sea level anomalies (SLAs) around Peninsular Malaysia on the order of 5-25 cm are mainly monsoon driven. Sea levels at eastern and western coasts respond differently to the Asian monsoon: two peaks per year in the Malacca Strait due to South Asian-Indian monsoon; an annual cycle in the remaining region mostly due to the East Asian-western Pacific monsoon. At interannual scale, regional sea level variability in the range of ±6 cm is correlated with El Nino-Southern Oscillation (ENSO). SLAs in the Malacca Strait side are further correlated with the Indian Ocean Dipole (IOD) in the range of ±5 cm. Interannual regional sea level falls are associated with El Nino events and positive phases of IOD, whilst rises are correlated with La Nina episodes and negative values of the IOD index. At seasonal to interannual scales, we observe the separation of the sea level patterns in the Singapore Strait, between the Raffles Lighthouse and Tanjong Pagar tide stations, likely caused by a dynamic constriction in the narrowest part. During the observation period 1986-2013, average relative rates of sea level rise derived from tide gauges in Malacca Strait and along the east coast of the peninsula are 3.6±1.6 and 3.7±1.1 mm yr-1, respectively. Correcting for respective VLMs (0.8±2.6 and 0.9±2.2 mm yr-1), their corresponding geocentric sea level rise rates

  5. The Red Sea during the Last Glacial Maximum: implications for sea level reconstructions

    Science.gov (United States)

    Gildor, H.; Biton, E.; Peltier, W. R.

    2006-12-01

    The Red Sea (RS) is a semi-enclosed basin connected to the Indian Ocean via a narrow and shallow strait, and surrounded by arid areas which exhibits high sensitivity to atmospheric changes and sea level reduction. We have used the MIT GCM to investigate the changes in the hydrography and circulation in the RS in response to reduced sea level, variability in the Indian monsoons, and changes in atmospheric temperature and humidity that occurred during the Last Glacial Maximum (LGM). The model results show high sensitivity to sea level reduction especially in the salinity field (increasing with the reduction in sea level) together with a mild atmospheric impact. Sea level reduction decreases the stratification, increases subsurface temperatures, and alters the circulation pattern at the Strait of Bab el Mandab, which experiences a transition from submaximal flow to maximal flow. The reduction in sea level at LGM alters the location of deep water formation which shifts to an open sea convective site in the northern part of the RS compared to present day situation in which deep water is formed from the Gulf of Suez outflow. Our main result based on both the GCM and on a simple hydraulic control model which takes into account mixing process at the Strait of Bab El Mandeb, is that sea level was reduced by only ~100 m in the Bab El Mandeb region during the LGM, i.e. the water depth at the Hanish sill (the shallowest part in the Strait Bab el Mandab) was around 34 m. This result agrees with the recent reconstruction of the LGM low stand of the sea in this region based upon the ICE-5G (VM2) model of Peltier (2004).

  6. MIS 5e relative sea-level changes in the Mediterranean Sea: Contribution of isostatic disequilibrium

    Science.gov (United States)

    Stocchi, Paolo; Vacchi, Matteo; Lorscheid, Thomas; de Boer, Bas; Simms, Alexander R.; van de Wal, Roderik S. W.; Vermeersen, Bert L. A.; Pappalardo, Marta; Rovere, Alessio

    2018-04-01

    Sea-level indicators dated to the Last Interglacial, or Marine Isotope Stage (MIS) 5e, have a twofold value. First, they can be used to constrain the melting of Greenland and Antarctic Ice Sheets in response to global warming scenarios. Second, they can be used to calculate the vertical crustal rates at active margins. For both applications, the contribution of glacio- and hydro-isostatic adjustment (GIA) to vertical displacement of sea-level indicators must be calculated. In this paper, we re-assess MIS 5e sea-level indicators at 11 Mediterranean sites that have been generally considered tectonically stable or affected by mild tectonics. These are found within a range of elevations of 2-10 m above modern mean sea level. Four sites are characterized by two separate sea-level stands, which suggest a two-step sea-level highstand during MIS 5e. Comparing field data with numerical modeling we show that (i) GIA is an important contributor to the spatial and temporal variability of the sea-level highstand during MIS 5e, (ii) the isostatic imbalance from the melting of the MIS 6 ice sheet can produce a >2.0 m sea-level highstand, and (iii) a two-step melting phase for the Greenland and Antarctic Ice Sheets reduces the differences between observations and predictions. Our results show that assumptions of tectonic stability on the basis of the MIS 5e records carry intrinsically large uncertainties, stemming either from uncertainties in field data and GIA models. The latter are propagated to either Holocene or Pleistocene sea-level reconstructions if tectonic rates are considered linear through time.

  7. The multimillennial sea-level commitment of global warming.

    Science.gov (United States)

    Levermann, Anders; Clark, Peter U; Marzeion, Ben; Milne, Glenn A; Pollard, David; Radic, Valentina; Robinson, Alexander

    2013-08-20

    Global mean sea level has been steadily rising over the last century, is projected to increase by the end of this century, and will continue to rise beyond the year 2100 unless the current global mean temperature trend is reversed. Inertia in the climate and global carbon system, however, causes the global mean temperature to decline slowly even after greenhouse gas emissions have ceased, raising the question of how much sea-level commitment is expected for different levels of global mean temperature increase above preindustrial levels. Although sea-level rise over the last century has been dominated by ocean warming and loss of glaciers, the sensitivity suggested from records of past sea levels indicates important contributions should also be expected from the Greenland and Antarctic Ice Sheets. Uncertainties in the paleo-reconstructions, however, necessitate additional strategies to better constrain the sea-level commitment. Here we combine paleo-evidence with simulations from physical models to estimate the future sea-level commitment on a multimillennial time scale and compute associated regional sea-level patterns. Oceanic thermal expansion and the Antarctic Ice Sheet contribute quasi-linearly, with 0.4 m °C(-1) and 1.2 m °C(-1) of warming, respectively. The saturation of the contribution from glaciers is overcompensated by the nonlinear response of the Greenland Ice Sheet. As a consequence we are committed to a sea-level rise of approximately 2.3 m °C(-1) within the next 2,000 y. Considering the lifetime of anthropogenic greenhouse gases, this imposes the need for fundamental adaptation strategies on multicentennial time scales.

  8. Holocene sea levels of Visakhapatnam shelf, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.M.; Rao, T.C.S.

    The Holocene sea level changes in the shelf areas off Visakhapatnam was studied from sediment distribution pattern and shallow seismic profiling. Morphological features on the shelf indicate a Late Pleistocene regression down to about -130 m below...

  9. Climate Prediction Center Indonesia Sea Level Pressure (1949-present)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is one of the CPC?s Monthly Atmospheric and SST Indices. It contains standardized sea level pressure anomalies over the equatorial Indonesia region...

  10. Vulnerability of wastewater infrastructure of coastal cities to sea level ...

    African Journals Online (AJOL)

    to sea level rise: A South African case study ... developing countries such as South Africa, and for their coastal cities. ... of the wastewater pipeline network is around 8 790 km and .... propensity for regional infrastructure to malfunction under.

  11. Chronology of Fluctuating Sea Levels since the Triassic

    Science.gov (United States)

    Haq, Bilal U.; Hardenbol, Jan; Vail, Peter R.

    1987-03-01

    Advances in sequence stratigraphy and the development of depositional models have helped explain the origin of genetically related sedimentary packages during sea level cycles. These concepts have provided the basis for the recognition of sea level events in subsurface data and in outcrops of marine sediments around the world. Knowledge of these events has led to a new generation of Mesozoic and Cenozoic global cycle charts that chronicle the history of sea level fluctuations during the past 250 million years in greater detail than was possible from seismic-stratigraphic data alone. An effort has been made to develop a realistic and accurate time scale and widely applicable chronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic frame-work. A description of this approach and an account of the results, illustrated by sea level cycle charts of the Cenozoic, Cretaceous, Jurassic, and Triassic intervals, are presented.

  12. Changes in Absolute Sea Level Along U.S. Coasts

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows changes in absolute sea level from 1960 to 2016 based on satellite measurements. Data were adjusted by applying an inverted barometer (air pressure)...

  13. Measurements of sea level off Tikkavanipalem - Coast India

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Desai, R.G.P.; Peshwe, V.B.; Desa, E.; VijayKumar, K.; Desa, E.S.; Mehra, P.; Nagvekar, S.

    , and meteorological measurements were also made during this one-year period. These measurements have indicated that the sea level along this coast contains contributions from several classes of motions, principally tidal motions and set-up/set-down motions...

  14. Present day sea level changes: observations and climatic causes

    International Nuclear Information System (INIS)

    Lombard, A.

    2007-01-01

    After a few thousand years of relative stability, sea level has risen of about 20 cm since the beginning of the 20. century. It currently rises at an average rate of about 3 mm/yr in response to global warming. About half of this rate is directly attributed to thermal expansion of sea water due to ocean warming, while the other half is mainly due to the melting of mountain glaciers and ice sheets. Satellite observations show that sea level rise is highly non-uniform. (author)

  15. Caspian Sea level changes during the last millennium: historical and geological evidences from the south Caspian Sea

    Science.gov (United States)

    Naderi Beni, A.; Lahijani, H.; Mousavi Harami, R.; Arpe, K.; Leroy, S. A. G.; Marriner, N.; Berberian, M.; Andrieu-Ponel, V.; Djamali, M.; Mahboubi, A.

    2013-03-01

    Historical literature may constitute a valuable source of information to reconstruct sea level changes. Here, historical documents and geological records have been combined to reconstruct Caspian sea-level (CSL) changes during the last millennium. In addition to a literature survey, new data from two short sediment cores were obtained from the south-eastern Caspian coast to identify coastal change driven by water-level changes. Two articulated bivalve shells from the marine facies were radiocarbon dated and calibrated to establish a chronology and to compare them with historical findings. The overall results indicate a high-stand during the Little Ice Age, up to -19 m, with a -28 m low-stand during the Medieval Climate Anomaly, while presently the CSL stands at -26.5 m. A comparison of the CSL curve with other lake systems and proxy records suggests that the main sea-level oscillations are essentially paced by solar irradiance. Although the major controller of the long-term CSL changes is driven by climatological factors, the seismicity of the basin could create locally changes in base level. These local base-level changes should be considered in any CSL reconstruction.

  16. Caspian sea-level changes during the last millennium: historical and geological evidence from the south Caspian Sea

    Science.gov (United States)

    Naderi Beni, A.; Lahijani, H.; Mousavi Harami, R.; Arpe, K.; Leroy, S. A. G.; Marriner, N.; Berberian, M.; Andrieu-Ponel, V.; Djamali, M.; Mahboubi, A.; Reimer, P. J.

    2013-07-01

    Historical literature may constitute a valuable source of information to reconstruct sea-level changes. Here, historical documents and geological records have been combined to reconstruct Caspian sea-level (CSL) changes during the last millennium. In addition to a comprehensive literature review, new data from two short sediment cores were obtained from the south-eastern Caspian coast to identify coastal change driven by water-level changes and to compare the results with other geological and historical findings. The overall results indicate a high-stand during the Little Ice Age, up to -21 m (and extra rises due to manmade river avulsion), with a -28 m low-stand during the Medieval Climate Anomaly, while presently the CSL stands at -26.5 m. A comparison of the CSL curve with other lake systems and proxy records suggests that the main sea-level oscillations are essentially paced by solar irradiance. Although the major controller of the long-term CSL changes is driven by climatological factors, the seismicity of the basin creates local changes in base level. These local base-level changes should be considered in any CSL reconstruction.

  17. Adapting to Rising Sea Level: A Florida Perspective

    Science.gov (United States)

    Parkinson, Randall W.

    2009-07-01

    Global climate change and concomitant rising sea level will have a profound impact on Florida's coastal and marine systems. Sea-level rise will increase erosion of beaches, cause saltwater intrusion into water supplies, inundate coastal marshes and other important habitats, and make coastal property more vulnerable to erosion and flooding. Yet most coastal areas are currently managed under the premise that sea-level rise is not significant and the shorelines are static or can be fixed in place by engineering structures. The new reality of sea-level rise and extreme weather due to climate change requires a new style of planning and management to protect resources and reduce risk to humans. Scientists must: (1) assess existing coastal vulnerability to address short term management issues and (2) model future landscape change and develop sustainable plans to address long term planning and management issues. Furthermore, this information must be effectively transferred to planners, managers, and elected officials to ensure their decisions are based upon the best available information. While there is still some uncertainty regarding the details of rising sea level and climate change, development decisions are being made today which commit public and private investment in real estate and associated infrastructure. With a design life of 30 yrs to 75 yrs or more, many of these investments are on a collision course with rising sea level and the resulting impacts will be significant. In the near term, the utilization of engineering structures may be required, but these are not sustainable and must ultimately yield to "managed withdrawal" programs if higher sea-level elevations or rates of rise are forthcoming. As an initial step towards successful adaptation, coastal management and planning documents (i.e., comprehensive plans) must be revised to include reference to climate change and rising sea-level.

  18. SEA-LEVEL RISE. Sea-level rise due to polar ice-sheet mass loss during past warm periods.

    Science.gov (United States)

    Dutton, A; Carlson, A E; Long, A J; Milne, G A; Clark, P U; DeConto, R; Horton, B P; Rahmstorf, S; Raymo, M E

    2015-07-10

    Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of sea-level rise from polar ice-sheet loss during past warm periods. Accounting for glacial isostatic processes helps to reconcile spatial variability in peak sea level during marine isotope stages 5e and 11, when the global mean reached 6 to 9 meters and 6 to 13 meters higher than present, respectively. Dynamic topography introduces large uncertainties on longer time scales, precluding robust sea-level estimates for intervals such as the Pliocene. Present climate is warming to a level associated with significant polar ice-sheet loss in the past. Here, we outline advances and challenges involved in constraining ice-sheet sensitivity to climate change with use of paleo-sea level records. Copyright © 2015, American Association for the Advancement of Science.

  19. Sea-Level Allowances along the World Coastlines

    Science.gov (United States)

    Vandewal, R.; Tsitsikas, C.; Reerink, T.; Slangen, A.; de Winter, R.; Muis, S.; Hunter, J. R.

    2017-12-01

    Sea level changes as a result of climate change. For projections we take ocean mass changes and volume changes into account. Including gravitational and rotational fingerprints this provide regional sea level changes. Hence we can calculate sea-level rise patterns based on CMIP5 projections. In order to take the variability around the mean state, which follows from the climate models, into account we use the concept of allowances. The allowance indicates the height a coastal structure needs to be increased to maintain the likelihood of sea-level extremes. Here we use a global reanalysis of storm surges and extreme sea levels based on a global hydrodynamic model in order to calculate allowances. It is shown that the model compares in most regions favourably with tide gauge records from the GESLA data set. Combining the CMIP5 projections and the global hydrodynamical model we calculate sea-level allowances along the global coastlines and expand the number of points with a factor 50 relative to tide gauge based results. Results show that allowances increase gradually along continental margins with largest values near the equator. In general values are lower at midlatitudes both in Northern and Southern Hemisphere. Increased risk for extremes are typically 103-104 for the majority of the coastline under the RCP8.5 scenario at the end of the century. Finally we will show preliminary results of the effect of changing wave heights based on the coordinated ocean wave project.

  20. Sea level change since 2005: importance of salinity

    Science.gov (United States)

    Llovel, W.; Purkey, S.; Meyssignac, B.; Kolodziejczyk, N.; Blazquez, A.; Bamber, J. L.

    2017-12-01

    Sea level rise is one of the most important consequences of the actual global warming. Global mean sea level has been rising at a faster rate since 1993 (over the satellite altimetry era) than previous decades. This rise is expected to accelerate over the coming decades and century. At global scale, sea level rise is caused by a combination of freshwater increase from land ice melting and land water changes (mass component) and ocean warming (thermal expansion). Estimating the causes is of great interest not only to understand the past sea level changes but also to validate projections based on climate models. In this study, we investigate the global mass contribution to recent sea level changes with an alternative approach by estimating the global ocean freshening. For that purpose, we consider the unprecedented amount of salinity measurements from Argo floats for the past decade (2005-2015). We compare our results to the ocean mass inferred by GRACE data and based on a sea level budget approach. Our results bring new constrains on the global water cycle (ocean freshening) and energy budget (ocean warming) as well as on the global ocean mass directly inferred from GRACE data.

  1. Statistical analysis of the acceleration of Baltic mean sea-level rise, 1900-2012

    Directory of Open Access Journals (Sweden)

    Birgit Hünicke

    2016-07-01

    Full Text Available We analyse annual mean sea-level records from tide-gauges located in the Baltic and parts of the North Sea with the aim of detecting an acceleration of sea-level rise over the 20textsuperscript{th} and 21textsuperscript{st} centuries. The acceleration is estimated as a (1 fit to a polynomial of order two in time, (2 a long-term linear increase in the rates computed over gliding overlapping decadal time segments, and (3 a long-term increase of the annual increments of sea level.The estimation methods (1 and (2 prove to be more powerful in detecting acceleration when tested with sea-level records produced in global climate model simulations. These methods applied to the Baltic-Sea tide-gauges are, however, not powerful enough to detect a significant acceleration in most of individual records, although most estimated accelerations are positive. This lack of detection of statistically significant acceleration at the individual tide-gauge level can be due to the high-level of local noise and not necessarily to the absence of acceleration.The estimated accelerations tend to be stronger in the north and east of the Baltic Sea. Two hypothesis to explain this spatial pattern have been explored. One is that this pattern reflects the slow-down of the Glacial Isostatic Adjustment. However, a simple estimation of this effect suggests that this slow-down cannot explain the estimated acceleration. The second hypothesis is related to the diminishing sea-ice cover over the 20textsuperscript{th} century. The melting o of less saline and colder sea-ice can lead to changes in sea-level. Also, the melting of sea-ice can reduce the number of missing values in the tide-gauge records in winter, potentially influencing the estimated trends and acceleration of seasonal mean sea-level This hypothesis cannot be ascertained either since the spatial pattern of acceleration computed for winter and summer separately are very similar. The all-station-average-record displays an

  2. Experiments in Reconstructing Twentieth-Century Sea Levels

    Science.gov (United States)

    Ray, Richard D.; Douglas, Bruce C.

    2011-01-01

    One approach to reconstructing historical sea level from the relatively sparse tide-gauge network is to employ Empirical Orthogonal Functions (EOFs) as interpolatory spatial basis functions. The EOFs are determined from independent global data, generally sea-surface heights from either satellite altimetry or a numerical ocean model. The problem is revisited here for sea level since 1900. A new approach to handling the tide-gauge datum problem by direct solution offers possible advantages over the method of integrating sea-level differences, with the potential of eventually adjusting datums into the global terrestrial reference frame. The resulting time series of global mean sea levels appears fairly insensitive to the adopted set of EOFs. In contrast, charts of regional sea level anomalies and trends are very sensitive to the adopted set of EOFs, especially for the sparser network of gauges in the early 20th century. The reconstructions appear especially suspect before 1950 in the tropical Pacific. While this limits some applications of the sea-level reconstructions, the sensitivity does appear adequately captured by formal uncertainties. All our solutions show regional trends over the past five decades to be fairly uniform throughout the global ocean, in contrast to trends observed over the shorter altimeter era. Consistent with several previous estimates, the global sea-level rise since 1900 is 1.70 +/- 0.26 mm/yr. The global trend since 1995 exceeds 3 mm/yr which is consistent with altimeter measurements, but this large trend was possibly also reached between 1935 and 1950.

  3. Development of a methodology for the assessment of sea level rise impacts on Florida's transportation modes and infrastructure : [summary].

    Science.gov (United States)

    2012-01-01

    In Florida, low elevations can make transportation infrastructure in coastal and low-lying areas potentially vulnerable to sea level rise (SLR). Becuase global SLR forecasts lack precision at local or regional scales, SLR forecasts or scenarios for p...

  4. Sea level change along the Black Sea coast from satellite altimetry, tide gauge and GPS observations

    Directory of Open Access Journals (Sweden)

    Nevin B. Avsar

    2016-01-01

    Full Text Available Sea level change affects human living conditions, particularly ocean coasts. However, sea level change is still unclear along the Black Sea coast due to lack of in-situ measurements and low resolution satellite data. In this paper, sea level change along the Black Sea coast is investigated from joint satellite altimetry, tide gauge (TG and Global Positioning System (GPS observations. The linear trend and seasonal components of sea level change are estimated at 8 TG stations (Amasra, Igneada, Trabzon-II, Sinop, Sile, Poti, Tuapse, and Batumi located along the Black Sea coast, which are compared with Satellite Altimetry and GPS. At the tide gauge stations with long-term records such as Poti (about 21 years and Tuapse (about 19 years, the results obtained from the satellite altimetry and tide gauge observations show a remarkably good agreement. While some big differences are existed between Satellite Altimetry and TG at other stations, after adding vertical motion from GPS, correlation coefficients of the trend have been greatly improved from 0.37 to 0.99 at 3 co-located GPS and TG stations (Trabzon-II, Sinop and Sile.

  5. Extending the Instrumental Record of Sea-Level Change: A 1300-Year Sea-Level Record From Eastern Connecticut

    Science.gov (United States)

    Donnelly, J. P.; Cleary, P.

    2002-12-01

    The instrumental record of sea-level change in the northeastern United States extends back to the early 20th century and at New York City (NYC) extends back to 1856. These tide gauge records indicate that sea level has risen at a rate of 2.5 to 4 mm/year over the last 100-150 years. Geologic evidence of sea-level change in the region over the last 2,000 years indicates rates of sea-level rise of about 1 mm/year or less. The discordance between the instrumental and geologic records is frequently cited as potentially providing evidence that anthropogenic warming of the climate system has resulted in an increase in the rate of sea-level rise. In order to begin to test the hypothesis that acceleration in the rate of sea-level rise has occurred in the last 150 years due to anthropogenic climate warming, accurate and precise information on the timing of the apparent acceleration in sea-level rise are needed. Here we construct a high-resolution relative sea-level record for the past 1350 years by dating basal salt marsh peat samples above a glacial erratic in a western Connecticut salt marsh. Preservation of marsh vegetation remains in the sediment record that has a narrow vertical habitat range at the upper end of the tidal range provides information on past sea levels. { \\it Spartina patens} (marsh hay) and { \\it Juncus gerardi} (black rush) dominate both the modern marsh and their remains are the major constituent of the marsh sediments and occur in the modern marsh between mean high water (MHW) and mean highest high water. We use the elevation distribution of modern plant communities to estimate the relationship of sediment samples to paleo-mean high water. The chronology is based on 15 radiocarbon ages, supplemented by age estimates derived from the horizons of industrial Pb pollution and pollen indicative of European land clearance. Thirteen of the radiocarbon ages and the Pb and pollen data come from samples taken along a contact between marsh peat and a glacial

  6. Orthogonal stack of global tide gauge sea level data

    Science.gov (United States)

    Trupin, A.; Wahr, J.

    1990-01-01

    Yearly and monthly tide gauge sea level data from around the globe are fitted to numerically generated equilibrium tidal data to search for the 18.6 year lunar tide and 14 month pole tide. Both tides are clearly evident in the results, and their amplitudes and phases are found to be consistent with a global equilibrium response. Global, monthly sea level data from outside the Baltic sea and Gulf of Bothnia are fitted to global atmospheric pressure data to study the response of the ocean to pressure fluctuations. The response is found to be inverted barometer at periods greater than two months. Global averages of tide gauge data, after correcting for the effects of post glacial rebound on individual station records, reveal an increase in sea level over the last 80 years of between 1.1 mm/yr and 1.9 mm/yr.

  7. Sea level: measuring the bounding surfaces of the ocean

    Science.gov (United States)

    Tamisiea, Mark E.; Hughes, Chris W.; Williams, Simon D. P.; Bingley, Richard M.

    2014-01-01

    The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. PMID:25157196

  8. Sea level: measuring the bounding surfaces of the ocean.

    Science.gov (United States)

    Tamisiea, Mark E; Hughes, Chris W; Williams, Simon D P; Bingley, Richard M

    2014-09-28

    The practical need to understand sea level along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global sea level. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of sea-level rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in sea level. While information from many scientific disciplines is needed to understand sea-level change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the sea surface and the Earth's crust. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  9. Challenges in Projecting Sea Level Rise impacts on the Coastal Environment of South Florida (Invited)

    Science.gov (United States)

    Obeysekera, J.; Park, J.; Irizarry-Ortiz, M. M.; Barnes, J. A.; Trimble, P.; Said, W.

    2010-12-01

    Due to flat topography, a highly transmissive groundwater aquifer, and a growing population with the associated infrastructure, South Florida’s coastal environment is one of the most vulnerable areas to sea level rise. Current projections of sea level rise and the associated storm surges will have direct impacts on coastal beaches and infrastructure, flood protection, freshwater aquifers, and both the isolated and regional wetlands. Uncertainties in current projections have made it difficult for regional and local governments to develop adaptation strategies as such measures will depend heavily on the temporal and spatial patterns of sea level rise in the coming decades. We demonstrate the vulnerability of both the built and natural environments of the coastal region and present the current efforts to understand and predict the sea level rise estimate that management agencies could employ in planning of adaptation strategies. In particular, the potential vulnerabilities of the flood control system as well as the threat to the water supply wellfields in the coastal belt will be presented. In an effort to understand the historical variability of sea level rise, we present linkages to natural phenomena such as Atlantic Multi-Decadal Oscillation, and the analytical methods we have developed to provide probabilistic projections of both mean sea level rise and the extremes.

  10. Detailed Tropical Sea Level Record Spanning the Younger Dryas Chronozone

    Science.gov (United States)

    Abdul, N. A.; Mortlock, R. A.; Wright, J. D.; Fairbanks, R. G.

    2010-12-01

    Variability in sea level is a fundamental measure of past changes in continental ice volume and provides an important benchmark to test climate change hypotheses. Records of the most recent deglaciation show two pulses of accelerated sea-level rise (Meltwater Pulses 1A and 1B) separated by an interval of slower sea level rise. The Younger Dryas chronozone falls within the interval between MWP 1A and 1B. It was first described over 100 years ago and remains one of the most studied periods in Earth’s history. The Younger Dryas was originally constrained with 14C dating to the interval between 11,000 and 10,000 14C years BP, which converts to 13,000 to 11,640 calendar years BP. The climatic expression of the Younger Dryas was most pronounced in the circum North Atlantic where climate proxies returned in some regions to near glacial values. Interpretations of the Younger Dryas’ significance range from a catastrophic global cooling event accompanied by Northern hemisphere ice sheet growth to simply regional changes in ocean and air mass mixing zones confined mainly to the North Atlantic. A detailed sea level record containing the interval from the end of MWP 1A to the beginning of MWP 1B (~14,000 to 11,300 years BP) was generated using 26 new U/Th dates from our 2007 Barbados offshore drilling expedition combined with our 1988 expedition measurements. 16 of these dates fall within the Younger Dryas Chronozone. Younger Dryas sea level positions were based on Acropora palmata samples from 3 overlapping and contemporaneous offshore drill cores (RGF 12 and BBDS 9 & 10) and corrected for minor tectonic uplift. From 14,000 to 11,300 years BP, sea level rose from ~81 to 56.5 m below present sea level with an initial rate of 10 m/kyr that decreased smoothly to <5 m/kyr at the base of MWP 1B. At the beginning of the Younger Dryas, sea level was at 69 m below present and rose 8 m by the end of this interval. In the context of the Barbados sea level record, the Younger Dryas

  11. Sea-Level Rise and Flood Potential along the California Coast

    Science.gov (United States)

    Delepine, Q.; Leung, C.

    2013-12-01

    Sea-level rise is becoming an ever-increasing problem in California. Sea-level is expected to rise significantly in the next 100 years, which will raise flood elevations in coastal communities. This will be an issue for private homeowners, businesses, and the state. One study suggests that Venice Beach could lose a total of at least $440 million in tourism spending and tax dollars from flooding and beach erosion if sea level rises 1.4 m by 2100. In addition, several airports, such as San Francisco International Airport, are located in coastal regions that have flooded in the past and will likely be flooded again in the next 30 years, but sea-level rise is expected to worsen the effects of flooding in the coming decades It is vital for coastal communities to understand the risks associated with sea-level rise so that they can plan to adapt to it. By obtaining accurate LiDAR elevation data from the NOAA Digital Coast Website (http://csc.noaa.gov/dataviewer/?keyword=lidar#), we can create flood maps to simulate sea level rise and flooding. The data are uploaded to ArcGIS and contour lines are added for different elevations that represent future coastlines during 100-year flooding. The following variables are used to create the maps: 1. High-resolution land surface elevation data - obtained from NOAA 2. Local mean high water level - from USGS 3. Local 100-year flood water level - from the Pacific Institute 4. Sea-level rise projections for different future dates (2030, 2050, and 2100) - from the National Research Council The values from the last three categories are added to represent sea-level rise plus 100-year flooding. These values are used to make the contour lines that represent the projected flood elevations, which are then exported as KML files, which can be opened in Google Earth. Once these KML files are made available to the public, coastal communities will gain an improved understanding of how flooding and sea-level rise might affect them in the future

  12. Spatial sea-level reconstruction in the Baltic Sea and in the Pacific Ocean from tide gauges observations

    Directory of Open Access Journals (Sweden)

    Marco Olivieri

    2016-07-01

    Full Text Available Exploiting the Delaunay interpolation, we present a newly implemented 2-D sea-level reconstruction from coastal sea-level observations to open seas, with the aim of characterizing the spatial variability of the rate of sea-level change. To test the strengths and weaknesses of this method and to determine its usefulness in sea-level interpolation, we consider the case studies of the Baltic Sea and of the Pacific Ocean. In the Baltic Sea, a small basin well sampled by tide gauges, our reconstructions are successfully compared with absolute sea-level observations from altimetry during 1993-2011. The regional variability of absolute sea level observed across the Pacific Ocean, however, cannot be reproduced. We interpret this result as the effect of the uneven and sparse tide gauge data set and of the composite vertical land movements in and around the region. Useful considerations arise that can serve as a basis for developing sophisticated approaches.

  13. How Much Are Floridians Willing to Pay for Protecting Sea Turtles from Sea Level Rise?

    Science.gov (United States)

    Hamed, Ahmed; Madani, Kaveh; Von Holle, Betsy; Wright, James; Milon, J Walter; Bossick, Matthew

    2016-01-01

    Sea level rise (SLR) is posing a great inundation risk to coastal areas. Some coastal nesting species, including sea turtle species, have experienced diminished habitat from SLR. Contingent valuation method (CVM) was used in an effort to assess the economic loss impacts of SLR on sea turtle nesting habitats for Florida coasts; and to elicit values of willingness to pay (WTP) of Central Florida residents to implement certain mitigation strategies, which would protect Florida's east coast sea turtle nesting areas. Using the open-ended and dichotomous choice CVM, we sampled residents of two Florida communities: Cocoa Beach and Oviedo. We estimated the WTP of households from these two cities to protect sea turtle habitat to be between $42 and $57 per year for 5 years. Additionally, we attempted to assess the impact of the both the respondents' demographics and their perception toward various situations on their WTP value. Findings include a negative correlation between the age of a respondent and the probability of an individual willing to pay the hypothetical WTP amount. We found that WTP of an individual was not dependent on prior knowledge of the effects of SLR on sea turtle habitat. The greatest indicators of whether or not an individual was willing to pay to protect sea turtle habitat were the respondents' perception regarding the trustworthiness and efficiency of the party which will implement the conservation measures and their confidence in the conservation methods used. Respondents who perceive sea turtles having an effect on their life were also more likely to pay.

  14. Relative sea-level change in the central Cyclades (Greece) since the Early Bronze Age

    Science.gov (United States)

    Draganits, E.

    2012-04-01

    The Aegean is a focus of important cultural achievements in Europe since the Neolithic period. The resulting abundance of archaeological remains, many of them below sea-level represent an advantageous area for the study of local relative sea-level change. We have carried out detailed mapping of Despotiko Island (SW of Antiparos) and its surrounding. Despotiko is situated almost exactly in the center of the Cyclades (as defined nowadays), more so than Delos, and therefore is very well suited for sea-level studies of the Cyclades. This beneficial location, combined with a spacious and protected bay, additionally may explain its former importance as stepping-stone in the Aegean Sea. The island is uninhabited at present, but Early Bronze Age settlement sites and graveyards as well as a large Archaic sanctuary proof its former importance. The sanctuary is situated on a gently northeast dipping slope in the northeast part of Despotiko, in range of sight of the Órmos Despotiko. Since 1997 large parts of this important sanctuary have been excavated during several excavation campaigns. Tectonically, Despotiko, Antiparos and Paros, belong to the Attic-Cycladic Crystalline of the Central Hellenides, a stack of metamorphic tectonic nappes, mainly comprising variable types of gneiss, schist, marble and amphibolite, and tectonic slices of unmetamorphosed sediments on top, separated by low-angle normal faults from the metamorphic units below. Submerged archaeological structures at the sea bottom of the Órmos Despotiko, a Classical marble inscription from the sanctuary and partly submerged agriculture trenches at the east coast Despotiko, indicate that the relative sea-level in this area was some 3 m lower during the Early Bronze Age and still more than 1 m lower during Classical time. These values of relative sea-level rise indicate a subsidence component additional to the global sea-level rise in the investigated time period. Neglecting possible vertical tectonic movements and

  15. Detection of a dynamic topography signal in last interglacial sea-level records.

    Science.gov (United States)

    Austermann, Jacqueline; Mitrovica, Jerry X; Huybers, Peter; Rovere, Alessio

    2017-07-01

    Estimating minimum ice volume during the last interglacial based on local sea-level indicators requires that these indicators are corrected for processes that alter local sea level relative to the global average. Although glacial isostatic adjustment is generally accounted for, global scale dynamic changes in topography driven by convective mantle flow are generally not considered. We use numerical models of mantle flow to quantify vertical deflections caused by dynamic topography and compare predictions at passive margins to a globally distributed set of last interglacial sea-level markers. The deflections predicted as a result of dynamic topography are significantly correlated with marker elevations (>95% probability) and are consistent with construction and preservation attributes across marker types. We conclude that a dynamic topography signal is present in the elevation of last interglacial sea-level records and that the signal must be accounted for in any effort to determine peak global mean sea level during the last interglacial to within an accuracy of several meters.

  16. History of Aral Sea level variability and current scientific debates

    Science.gov (United States)

    Cretaux, Jean-François; Letolle, René; Bergé-Nguyen, Muriel

    2013-11-01

    The Aral Sea has shrunk drastically over the past 50 years, largely due to water abstraction from the Amu Darya and Syr Darya rivers for land irrigation. Over a longer timescale, Holocene palaeolimnological reconstruction of variability in water levels of the Aral Sea since 11,700 BP indicates a long history of alternating phases of regression and transgression, which have been attributed variously to climate, tectonic and anthropogenic forcing. The hydrological history of the Aral Sea has been investigated by application of a variety of scientific approaches, including archaeology, palaeolimnological palaeoclimate reconstruction, geophysics, sedimentology, and more recently, space science. Many issues concerning lake level variability over the Holocene and more recent timescales, and the processes that drive the changes, are still a matter for active debate. Our aim in this article is to review the current debates regarding key issues surrounding the causes and magnitude of Aral Sea level variability on a variety of timescales from months to thousands of years. Many researchers have shown that the main driving force of Aral Sea regressions and transgressions is climate change, while other authors have argued that anthropogenic forcing is the main cause of Aral Sea water level variations over the Holocene. Particular emphasis is made on contributions from satellite remote sensing data in order to improve our understanding of the influence of groundwater on the current hydrological water budget of the Aral Sea since 2005. Over this period of time, water balance computation has been performed and has shown that the underground water inflow to the Aral Sea is close to zero with an uncertainty of 3 km3/year.

  17. Why is mean sea level along the Indian coast higher in the Bay of Bengal than in the Arabian Sea?

    Digital Repository Service at National Institute of Oceanography (India)

    Shankar, D.; Shetye, S.R.

    Levelling observations conducted during the Great Trigonometrical Survey of India (1858-1909) and subsequent observations showed that mean sea level along the coast of India is higher in the Bay of Bengal than in the Arabian Sea, the difference...

  18. Sea level trend and variability around the Peninsular Malaysia

    Science.gov (United States)

    Luu, Q. H.; Tkalich, P.; Tay, T. W.

    2014-06-01

    Peninsular Malaysia is bounded from the west by Malacca Strait and the Andaman Sea both connected to the Indian Ocean, and from the east by South China Sea being largest marginal sea in the Pacific Basin. Resulting sea level along Peninsular Malaysia coast is assumed to be governed by various regional phenomena associated with the adjacent parts of the Indian and Pacific Oceans. At annual scale, sea level anomalies (SLAs) are generated by the Asian monsoon; interannual sea level variability is determined by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD); while long-term sea level trend is related to global climate change. To quantify the relative impacts of these multi-scale phenomena on sea level trend and variability around the Peninsular Malaysia, long-term tide gauge record and satellite altimetry are used. During 1984-2011, relative sea level rise (SLR) rates in waters of Malacca Strait and eastern Peninsular Malaysia are found to be 2.4 ± 1.6 mm yr-1 and 2.7 ± 1.0 mm yr-1, respectively. Allowing for corresponding vertical land movements (VLM; 0.8 ± 2.6 mm yr-1 and 0.9 ± 2.2 mm yr-1), their absolute SLR rates are 3.2 ± 4.2 mm yr-1 and 3.6 ± 3.2 mm yr-1, respectively. For the common period 1993-2009, absolute SLR rates obtained from both tide gauge and satellite altimetry in Peninsular Malaysia are similar; and they are slightly higher than the global tendency. It further underlines that VLM should be taken into account to get better estimates of SLR observations. At interannual scale, ENSO affects sea level over the Malaysian coast in the range of ±5 cm with a very high correlation. Meanwhile, IOD modulates sea level anomalies mainly in the Malacca Strait in the range of ±2 cm with a high correlation coefficient. Interannual regional sea level drops are associated with El Niño events and positive phases of the IOD index; while the rises are correlated with La Niña episodes and the negative periods of the IOD index

  19. Loss of cultural world heritage and currently inhabited places to sea-level rise

    International Nuclear Information System (INIS)

    Marzeion, Ben; Levermann, Anders

    2014-01-01

    The world population is concentrated near the coasts, as are a large number of Cultural World Heritage sites, defined by the UNESCO. Using spatially explicit sea-level estimates for the next 2000 years and high-resolution topography data, we compute which current cultural heritage sites will be affected by sea-level rise at different levels of sustained future warming. As indicators for the pressure on future cultural heritage we estimate the percentage of each country’s area loss, and the percentage of current population living in regions that will be permanently below sea level, for different temperature levels. If the current global mean temperature was sustained for the next two millennia, about 6% (40 sites) of the UNESCO sites will be affected, and 0.7% of global land area will be below mean sea level. These numbers increase to 19% (136 sites) and 1.1% for a warming of 3 K. At this warming level, 3–12 countries will experience a loss of more than half of their current land surface, 25–36 countries lose at least 10% of their territory, and 7% of the global population currently lives in regions that will be below local sea level. Given the millennial scale lifetime of carbon dioxide in the atmosphere, our results indicate that fundamental decisions with regard to mankind’s cultural heritage are required. (paper)

  20. Evaluation of sea level rise in Bohai Bay and associated responses

    Directory of Open Access Journals (Sweden)

    Ke-Xiu LIU

    2017-03-01

    Full Text Available Tide gauge data from 1950 to 2015 are used to analyze sea level change, tidal change, return levels, and design tide levels under rising sea level scenarios in Bohai Bay. Results show the following: 1 Since 1950 sea levels in Bohai Bay show a significant rising trend of 3.3 mm per year. The speed has been particularly rapid in 1980–2015 at a rate of 4.7 mm per year. 2 Astronomical tides showed a clear long-term trend in 1950–2015. The amplitude and phase lag of the M2 tide constituent decreased at a rate of 0.21 cm per year and 0.11° per year, respectively and the phase lag of K1 decreased at a rate of 0.09° per year, whereas there was little change in its amplitude. The mean high and low tides increased at a rate of 0.08 and 0.52 cm per year, respectively, whereas the mean tidal range decreased at a rate of 0.44 cm per year. Results from numerical experiments show that local sea level rise plays an important role in the tidal dynamics change in Bohai Bay. 3 It is considered that the sea level return periods will decrease owing to the influence of sea level rise and land subsidence, therefore design tide level will change in relation to sea level rise. Therefore, the ability of seawalls to withstand water will diminish, and storm surge disasters will become more serious in the future.

  1. A 500 kyr record of global sea-level oscillations in the Gulf of Lion, Mediterranean Sea: new insights into MIS 3 sea-level variability

    Directory of Open Access Journals (Sweden)

    J. Frigola

    2012-06-01

    Full Text Available Borehole PRGL1-4 drilled in the upper slope of the Gulf of Lion provides an exceptional record to investigate the impact of late Pleistocene orbitally-driven glacio-eustatic sea-level oscillations on the sedimentary outbuilding of a river fed continental margin. High-resolution grain-size and geochemical records supported by oxygen isotope chronostratigraphy allow reinterpreting the last 500 ka upper slope seismostratigraphy of the Gulf of Lion. Five main sequences, stacked during the sea-level lowering phases of the last five glacial-interglacial 100-kyr cycles, form the upper stratigraphic outbuilding of the continental margin. The high sensitivity of the grain-size record down the borehole to sea-level oscillations can be explained by the great width of the Gulf of Lion continental shelf. Sea level driven changes in accommodation space over the shelf cyclically modified the depositional mode of the entire margin. PRGL1-4 data also illustrate the imprint of sea-level oscillations at millennial time-scale, as shown for Marine Isotopic Stage 3, and provide unambiguous evidence of relative high sea-levels at the onset of each Dansgaard-Oeschger Greenland warm interstadial. The PRGL1-4 grain-size record represents the first evidence for a one-to-one coupling of millennial time-scale sea-level oscillations associated with each Dansgaard-Oeschger cycle.

  2. Holocene sea level, a semi-empirical contemplation

    Science.gov (United States)

    Bittermann, K.; Kemp, A.; Vermeer, M.; Rahmstorf, S.

    2017-12-01

    Holocene eustatic sea level from approximately -10,000-1800 CE was characterized by an increase of about 60m, with the rate progressively slowing down until sea level almost stabilizes between 500-1800 CE. Global and northern-hemisphere temperatures rose from the last glacial termination until the `Holocene Optimum'. From ­­there, up to the start of the recent anthropogenic rise, they almost steadily decline. How are the sea-level and temperature evolutions linked? We investigate this with semi-empirical sea-level models. We found that, due to the nature of Milankovitch forcing, northern-hemisphere temperature (we used the Greenland temperature by Vinther et al., 2009) is a better model driver than global mean temperature because the evolving mass of northern-hemisphere land ice was the dominant cause of Holocene global sea-level trends. The adjustment timescale for this contribution is 1200 years (900-1500 years; 90% confidence interval). To fit the observed sea-level history, the model requires a small additional constant rate (Bittermann 2016). This rate turns out to be of the same order of magnitude as reconstructions of Antarctic sea-level contributions (Briggs et al. 2014, Golledge et al. 2014). In reality this contribution is unlikely to be constant but rather has a dominant timescale that is large compared to the time considered. We thus propose that Holocene sea level can be described by a linear combination of a temperature driven rate, which becomes negative in the late Holocene (as Northern Hemisphere ice masses are diminished), and a positive, approximately constant term (possibly from Antarctica), which starts to dominate from the middle of the Holocene until the start of industrialization. Bibliography: Bittermann, K. 2016. Semi-empirical sea-level modelling. PhD Thesis University of Potsdam. Briggs, R.D., et al. 2014. A data-constrained large ensemble analysis of Antarctic evolution since the Eemian. Quaternary science reviews, 103, 91

  3. Sea-level rise risks to coastal cities

    Science.gov (United States)

    Nicholls, Robert J.

    2017-04-01

    Understanding the consequence of sea-level rise for coastal cities has long lead times and huge political implications. Civilisation has emerged and developed during a period of several thousand years during which in geological terms sea level has been unusually stable. We have now moved out of this period and the challenge will be to develop a long-term proactive assessment approach to manage this challenge. In 2005 there were 136 coastal cities with a population exceeding one million people and a collective population of 400 million people. All these coastal cities are threatened by flooding from the sea to varying degrees and these risks are increasing due to growing exposure (people and assets), rising sea levels due to climate change, and in some cities, significant coastal subsidence due to human agency (drainage and groundwater withdrawals from susceptible soils). In these cities we wish to avoid major flood events, with associated damage and potentially deaths and ultimately decline of the cities. Flood risks grow with sea-level rise as it raises extreme sea levels. As sea levels continue to rise, protection will have to be progressively upgraded. Even with this, the magnitude of losses when flood events do occur would increase as coastal cities expand, and water depths and hence unit damage increase with sea-level rise/subsidence. This makes it critical to also prepare for larger coastal flood disasters than we experience today and raises questions on the limits to adaptation. There is not an extensive literature or significant empirical information on the limits to adaptation in coastal cities. These limits are not predictable in a formal sense - while the rise in mean sea level raises the likelihood of a catastrophic flood, extreme events are what cause damage and trigger a response, be it abandonment, a defence upgrade or something else. There are several types of potential limits that could be categorised into three broad types: • Physical

  4. Modal recovery of sea-level variability in the South China Sea using merged altimeter data

    Science.gov (United States)

    Jiang, Haoyu; Chen, Ge

    2015-09-01

    Using 20 years (1993-2012) of merged data recorded by contemporary multi-altimeter missions, a variety of sea-level variability modes are recovered in the South China Sea employing three-dimensional harmonic extraction. In terms of the long-term variation, the South China Sea is estimated to have a rising sea-level linear trend of 5.39 mm/a over these 20 years. Among the modes extracted, the seven most statistically significant periodic or quasi-periodic modes are identified as principal modes. The geographical distributions of the magnitudes and phases of the modes are displayed. In terms of intraannual and annual regimes, two principal modes with strict semiannual and annual periods are found, with the annual variability having the largest amplitudes among the seven modes. For interannual and decadal regimes, five principal modes at approximately 18, 21, 23, 28, and 112 months are found with the most mode-active region being to the east of Vietnam. For the phase distributions, a series of amphidromes are observed as twins, termed "amphidrome twins", comprising rotating dipole systems. The stability of periodic modes is investigated employing joint spatiotemporal analysis of latitude/longitude sections. Results show that all periodic modes are robust, revealing the richness and complexity of sea-level modes in the South China Sea.

  5. Increasing Resilience Through Engagement In Sea Level Rise Community Science Initiatives.

    Science.gov (United States)

    Chilton, L. A.; Rindge, H.

    2017-12-01

    Science literate and engaged members of the public, including students, are critical to building climate resilient communities. USC Sea Grant facilitates programs that work to build and strengthen these connections. The Urban Tides Community Science Initiative (Urban Tides) and the Youth Exploring Sea Level Rise Science Program (YESS) engage communities across the boundaries of public engagement, K-12 education, and informal education. YESS is an experiential sea level rise education program that combines classroom learning, field investigations and public presentations. Students explore sea level rise using a new curricula, collect their own data on sea level rise, develop communication products, and present their findings to city governments, researchers, and others. Urban Tides engages community members, informal education centers, K-12 students, and local government leaders in a citizen science program photo- documenting extreme high tides, erosion and coastal flooding in Southern California. Images provide critical information to help calibrate scientific models used to identify locations vulnerable to damage from future sea level rise. These tools and information enable community leaders and local governments to set priorities, guidelines, and update policies as they plan strategies that will help the region adapt. The program includes a mobile app for data collection, an open database to view photos, a lesson plan, and community beach walks. Urban Tides has led to an increase in data and data-gathering capacity for regional scientists, an increase in public participation in science, and an increase in ocean and climate literacy among initiative participants. Both of these programs bring informed and diverse voices into the discussion of how to adapt and build climate resilient communities. USC Sea Grant will share impacts and lessons learned from these two unique programs.

  6. Global and local level density models

    International Nuclear Information System (INIS)

    Koning, A.J.; Hilaire, S.; Goriely, S.

    2008-01-01

    Four different level density models, three phenomenological and one microscopic, are consistently parameterized using the same set of experimental observables. For each of the phenomenological models, the Constant Temperature Model, the Back-shifted Fermi gas Model and the Generalized Superfluid Model, a version without and with explicit collective enhancement is considered. Moreover, a recently published microscopic combinatorial model is compared with the phenomenological approaches and with the same set of experimental data. For each nuclide for which sufficient experimental data exists, a local level density parameterization is constructed for each model. Next, these local models have helped to construct global level density prescriptions, to be used for cases for which no experimental data exists. Altogether, this yields a collection of level density formulae and parameters that can be used with confidence in nuclear model calculations. To demonstrate this, a large-scale validation with experimental discrete level schemes and experimental cross sections and neutron emission spectra for various different reaction channels has been performed

  7. Genetic Programming for Sea Level Predictions in an Island Environment

    Directory of Open Access Journals (Sweden)

    M.A. Ghorbani

    2010-03-01

    Full Text Available Accurate predictions of sea-level are important for geodetic applications, navigation, coastal, industrial and tourist activities. In the current work, the Genetic Programming (GP and artificial neural networks (ANNs were applied to forecast half-daily and daily sea-level variations from 12 hours to 5 days ahead. The measurements at the Cocos (Keeling Islands in the Indian Ocean were used for training and testing of the employed artificial intelligence techniques. A comparison was performed of the predictions from the GP model and the ANN simulations. Based on the comparison outcomes, it was found that the Genetic Programming approach can be successfully employed in forecasting of sea level variations.

  8. Topex-Poseidon analysis of sea level variability over the Atlantic Ocean

    Science.gov (United States)

    Catalan P-U, M.; Villares, P.; Catalan, M.; Gomez-Enri, J.

    2003-04-01

    The variability of sea level and surface geostrophic currents in Atlantic Ocean is investigated using 333 cycles of altimeter information obtained by TOPEX-POSEIDON satellite. After the improvements of orbit accuracy, the most important concern to studies of sea level variability from altimeter height data are related with the formalism used for modelling the altimetric measurement corrections. Presently, one of the main sources of potential error is the correction for atmospheric pressure loading, the so-called ‘inverse barometer effect’. As is well known, this correction is intended to adjust the sea surface elevation for the static effects of the downward force of the mass of the atmosphere on the sea surface, adjusted, in this oversimplified model in 1cm/mbar. The exact response of the sea surface to atmospheric pressure loading depends on the space and time scales of the pressure field and must be specially a concern at high latitudes where atmospheric pressure fluctuations are large due to the intensity of low pressure fields at these latitudes and the additional uncertainty in the model estimates of the local sea level pressure. To study these effects over the whole Atlantic Ocean we compute a linear regression adjustment and an Empirical Orthogonal Functions Decomposition (EOFD), between sea level variation without inverse barometer correction and the atmospheric pressure, in all the Topex-Poseidon cross points over the whole Atlantic, including both the Artic and Antarctic Oceans. We use the barometric factor computed from the linear regression to correct the satellite mean sea level variation, comparing the correlation with the pressure. Our results show an important improvement in the decorrelation between sea level and atmospheric pressure time series, compared with the use of Inverse Barometer model, at most of the satellite cross points. The complicated nature of sea level variability at high latitudes justify that EOFD analysis conclusions

  9. Detecting sea-level hazards: Simple regression-based methods for calculating the acceleration of sea level

    Science.gov (United States)

    Doran, Kara S.; Howd, Peter A.; Sallenger,, Asbury H.

    2016-01-04

    This report documents the development of statistical tools used to quantify the hazard presented by the response of sea-level elevation to natural or anthropogenic changes in climate and ocean circulation. A hazard is a physical process (or processes) that, when combined with vulnerability (or susceptibility to the hazard), results in risk. This study presents the development and comparison of new and existing sea-level analysis methods, exploration of the strengths and weaknesses of the methods using synthetic time series, and when appropriate, synthesis of the application of the method to observed sea-level time series. These reports are intended to enhance material presented in peer-reviewed journal articles where it is not always possible to provide the level of detail that might be necessary to fully support or recreate published results.

  10. Mass-induced [|#8#|]Sea Level Variations in the Red Sea from Satellite Altimetry and GRACE

    Science.gov (United States)

    Feng, W.; Lemoine, J.; Zhong, M.; Hsu, H.

    2011-12-01

    We have analyzed mass-induced sea level variations (SLVs) in the Red Sea from steric-corrected altimetry and GRACE between January 2003 and December 2010. The steric component of SLVs in the Red Sea calculated from climatological temperature and salinity data is relatively small and anti-phase with the mass-induced SLV. The total SLV in the Red Sea is mainly driven by the mass-induced SLV, which increases in winter when the Red Sea gains the water mass from the Gulf of Aden and vice versa in summer. Spatial and temporal patterns of mass-induced SLVs in the Red Sea from steric-corrected altimetry agree very well with GRACE observations. Both of two independent observations show high annual amplitude in the central Red Sea (>20cm). Total mass-induced SLVs in the Red Sea from two independent observations have similar annual amplitude and phase. One main purpose of our work is to see whether GRGS's ten-day GRACE results can observe intra-seasonal mass change in the Red Sea. The wavelet coherence analysis indicates that GRGS's results show the high correlation with the steric-corrected SLVs on intra-seasonal time scale. The agreement is excellent for all the time-span until 1/3 year period and is patchy between 1/3 and 1/16 year period. Furthermore, water flux estimates from current-meter arrays and moorings show mass gain in winter and mass loss in summer, which is also consistent with altimetry and GRACE.

  11. Sea level trend and variability in the Singapore Strait

    Digital Repository Service at National Institute of Oceanography (India)

    Tkalich, P.; Vethamony, P.; Luu, Q.-H.; Babu, M.T.

    www.ocean-sci.net/9/293/2013/ doi:10.5194/os-9-293-2013 © Author(s) 2013. CC Attribution 3.0 License. EGU Journal Logos (RGB) Advances in Geosciences O pen A ccess Natural Hazards and Earth System Sciences O pen A ccess Annales Geophysicae O pen A... Sci., 9, 293–300, 2013 www.ocean-sci.net/9/293/2013/ P. Tkalich et al.: Sea level in Singapore Strait 295 likely to be the cause for modulating the inter-annual sea level variability associated with ENSO. On the Sunda Shelf and particularly in SS, our...

  12. Land Sea Level Difference Impacts on Socio-Hydrological System.

    Science.gov (United States)

    Sung, K.; Yu, D. J.; Oh, W. S.; Sangwan, N.

    2016-12-01

    Allowing moderate shocks can be a new solution that helps to build adaptive capacity in society is a rising issue. In Social-Ecological field, Carpenter et al. (2015) suggested that exposure to short-term variability leads to long term resilience by enlarging safe operating space (SOS). The SOS refers to the boundary of favorable state that ecosystem can maintain resilience without imposing certain conditions (Carpenter et al. 2015). Our work is motivated by defining SOS in socio-hydrological system(SHS) because it can be an alternative way for flood management beyond optimized or robust flood control. In this context, large flood events that make system to cross the SOS should be fully managed, but frequent small floods need to be allowed if the system is located in SOS. Especially, land sea level change is critical factor to change flood resilience since it is one of the most substantial disturbance that changes the entire boundary of SOS. In order to have broader perspective of vulnerability and resilience of the coastal region, it is crucial to understand the land sea level dynamics changed with human activities and natural variances.The risk of land sea level change has been researched , but most of these researches have focused on explain cause and effect of land sea level change, paying little attention to its dynamics interacts with human activities. Thus, an objective of this research is to study dynamics of human work, land sea level change and resilience to flood with SOS approach. Especially, we focus on the case in Ganges-Brahmaputra, Bangladesh where has high vulnerability to flood, and is faced with relatively rapid land sea level change problem. To acheive the goal, this study will develop a stylized model by extending the human - flood interaction model combined with relative sea level difference equation. The model describes the dynamics of flood protection system which is changed by SHS and land sea level chage. we will focus on the aggradation

  13. The Impact of Sea Level Rise on Florida's Everglades

    Science.gov (United States)

    Senarath, S. U.

    2005-12-01

    Global warming and the resulting melting of polar ice sheets could increase global sea levels significantly. Some studies have predicted mean sea level increases in the order of six inches to one foot in the next 25 to 50 years. This could have severe irreversible impacts on low-lying areas of Florida's Everglades. The key objective of this study is to evaluate the effects of a one foot sea level rise on Cape Sable Seaside Sparrow (CSSS) nesting areas within the Everglades National Park (ENP). A regional-scale hydrologic model is used to assess the sensitivities of this sea-level rise scenario. Florida's Everglades supports a unique ecosystem. At present, about 50 percent of this unique ecosystem has been lost due to urbanization and farming. Today, the water flow in the remnant Everglades is also regulated to meet a variety of competing environmental, water-supply and flood-control needs. A 30-year, eight billion dollar (1999 estimate) project has been initiated to improve Everglades' water flows. The expected benefits of this restoration project will be short-lived if the predicted sea level rise causes severe impacts on the environmentally sensitive areas of the Everglades. Florida's Everglades is home to many threatened and endangered species of wildlife. The Cape Sable Seaside Sparrow population in the ENP is one such species that is currently listed as endangered. Since these birds build their nests close to the ground surface (the base of the nest is approximately six inches from the ground surface), they are directly affected by any sea level induced ponding depth, frequency or duration change. Therefore, the CSSS population serves as a good indicator species for evaluating the negative impacts of sea level rise on the Everglades' ecosystem. The impact of sea level rise on the CSSS habitat is evaluated using the Regional Simulation Model (RSM) developed by the South Florida Water Management District. The RSM is an implicit, finite-volume, continuous

  14. Postglacial relative sea level change at Fildes Peninsula, King George Island (West Antarctic

    Directory of Open Access Journals (Sweden)

    K. V. Polishchuk

    2016-01-01

    Full Text Available Analysis and integration of data obtained in our field and laboratory investigations of 2008–2012 together with results of previous paleogeographic studies were conducted to reveal parameters and factors of the post-glacial changes in the relative sea-level on the Fildes Peninsula and the King George Island. Results of dating of organic material taken from cross-sections of Quaternary deposits, data on morphology of marine landforms as well as on bottom sediments in lakes were used to construct a curve of changes in the relative sea-level.Our research has shown that the rapid rise of relative sea level in the area (since the beginning of the Holocene decelerated about 8000 years BP, achieving its maximum about 7000 years BP. This was followed by the fall of relative sea-level (the land elevation by 18–20  m in total, and it was characterized by relatively high rate of fall during periods of 6000– 5000 years BP, 4000–2500 years BP, and during the last 1500 years; the rate decreased in 5000–4000 years BP and 2500– 1600 years BP. The changes in relative sea level in this region were determined by the following factors: the eustatic component of the global changes in sea-level and, possibly, oscillations in the global sea level of another nature; local parameters of the Last glacial maximum; a course of the Peninsula deglaciation; regional physical characteristics of the Earth's crust and the mantle substances; local tectonic processes, including the isostatic rebound. Since the beginning of the Holocene up to about 7000 years BP, the main contribution to changes of the relative sea-level in this area was made by the global eustatic factor. The subsequent fall of the relative sea-level (elevation of the Peninsula surface proceeded under condition of reduced role of the eustatic factor and predominance of other factors.

  15. Effective inundation of continental United States communities with 21st century sea level rise

    Directory of Open Access Journals (Sweden)

    Kristina A. Dahl

    2017-07-01

    Full Text Available Recurrent, tidally driven coastal flooding is one of the most visible signs of sea level rise. Recent studies have shown that such flooding will become more frequent and extensive as sea level continues to rise, potentially altering the landscape and livability of coastal communities decades before sea level rise causes coastal land to be permanently inundated. In this study, we identify US communities that will face effective inundation—defined as having 10% or more of livable land area flooded at least 26 times per year—with three localized sea level rise scenarios based on projections for the 3rd US National Climate Assessment. We present these results in a new, online interactive tool that allows users to explore when and how effective inundation will impact their communities. In addition, we identify communities facing effective inundation within the next 30 years that contain areas of high socioeconomic vulnerability today using a previously published vulnerability index. With the Intermediate-High and Highest sea level rise scenarios, 489 and 668 communities, respectively, would face effective inundation by the year 2100. With these two scenarios, more than half of communities facing effective inundation by 2045 contain areas of current high socioeconomic vulnerability. These results highlight the timeframes that US coastal communities have to respond to disruptive future inundation. The results also underscore the importance of limiting future warming and sea level rise: under the Intermediate-Low scenario, used as a proxy for sea level rise under the Paris Climate Agreement, 199 fewer communities would be effectively inundated by 2100.

  16. Modelling sea level rise impacts on storm surges along US coasts

    International Nuclear Information System (INIS)

    Tebaldi, Claudia; Strauss, Benjamin H; Zervas, Chris E

    2012-01-01

    Sound policies for protecting coastal communities and assets require good information about vulnerability to flooding. Here, we investigate the influence of sea level rise on expected storm surge-driven water levels and their frequencies along the contiguous United States. We use model output for global temperature changes, a semi-empirical model of global sea level rise, and long-term records from 55 nationally distributed tidal gauges to develop sea level rise projections at each gauge location. We employ more detailed records over the period 1979–2008 from the same gauges to elicit historic patterns of extreme high water events, and combine these statistics with anticipated relative sea level rise to project changing local extremes through 2050. We find that substantial changes in the frequency of what are now considered extreme water levels may occur even at locations with relatively slow local sea level rise, when the difference in height between presently common and rare water levels is small. We estimate that, by mid-century, some locations may experience high water levels annually that would qualify today as ‘century’ (i.e., having a chance of occurrence of 1% annually) extremes. Today’s century levels become ‘decade’ (having a chance of 10% annually) or more frequent events at about a third of the study gauges, and the majority of locations see substantially higher frequency of previously rare storm-driven water heights in the future. These results add support to the need for policy approaches that consider the non-stationarity of extreme events when evaluating risks of adverse climate impacts. (letter)

  17. Accelerated sea level rise and Florida Current transport

    Directory of Open Access Journals (Sweden)

    J. Park

    2015-07-01

    Full Text Available The Florida Current is the headwater of the Gulf Stream and is a component of the North Atlantic western boundary current from which a geostrophic balance between sea surface height and mass transport directly influence coastal sea levels along the Florida Straits. A linear regression of daily Florida Current transport estimates does not find a significant change in transport over the last decade; however, a nonlinear trend extracted from empirical mode decomposition (EMD suggests a 3 Sv decline in mean transport. This decline is consistent with observed tide gauge records in Florida Bay and the straits exhibiting an acceleration of mean sea level (MSL rise over the decade. It is not known whether this recent change represents natural variability or the onset of the anticipated secular decline in Atlantic meridional overturning circulation (AMOC; nonetheless, such changes have direct impacts on the sensitive ecological systems of the Everglades as well as the climate of western Europe and eastern North America.

  18. Relative Sea Level Trends Along the Coast of the Bay of Bengal

    Science.gov (United States)

    Becker, M.; Calmant, S.; Papa, F.; Delebecque, C.; Islam, A. S.; Shum, C. K.

    2016-12-01

    In the coastal belt of the Bay of Bengal, the sea level rise is one of a major threat, linked to climate change, which drastically affects the livelihoods of millions of people. A comprehensive understanding of sea level trends and its variability in this region is therefore crucial and should help to anticipate the impacts of climate change and implement adaptation strategies. This region is bordered mostly by Bangladesh, India, Malaysia, Myanmar, and Thailand. Here, we revisit the sea level changes in the Bay of Bengal region from tide gauges and satellite altimetry over the period 1993-2014. The 23 monthly mean tide gauge records, used in this study, are retrieved from PSMSL (15 records) and supplemented with Bangladeshi observations (8 records). We show that, over the satellite altimetry era, the sea level interannual/decadal variability is mainly due to ocean thermal expansion variability driven by IOD/ENSO events and their low frequency modulation. We focus on relative sea level rise at major coastal cities and try to separate the climatic signal (long term trend plus interannual/decadal variability) from local effects, in particular vertical land movements. Results from GPS are analysed where available. When no such data exist, vertical land movements are deduced from the combined use of tide gauge and altimetry data. While the analysis is performed over the whole region, a particular attention is given to the low-lyingBangladesh's coastal area.

  19. Salt marsh persistence is threatened by predicted sea-level rise

    Science.gov (United States)

    Crosby, Sarah C.; Sax, Dov F.; Palmer, Megan E.; Booth, Harriet S.; Deegan, Linda A.; Bertness, Mark D.; Leslie, Heather M.

    2016-11-01

    Salt marshes buffer coastlines and provide critical ecosystem services from storm protection to food provision. Worldwide, these ecosystems are in danger of disappearing if they cannot increase elevation at rates that match sea-level rise. However, the magnitude of loss to be expected is not known. A synthesis of existing records of salt marsh elevation change was conducted in order to consider the likelihood of their future persistence. This analysis indicates that many salt marshes did not keep pace with sea-level rise in the past century and kept pace even less well over the past two decades. Salt marshes experiencing higher local sea-level rise rates were less likely to be keeping pace. These results suggest that sea-level rise will overwhelm most salt marshes' capacity to maintain elevation. Under the most optimistic IPCC emissions pathway, 60% of the salt marshes studied will be gaining elevation at a rate insufficient to keep pace with sea-level rise by 2100. Without mitigation of greenhouse gas emissions this potential loss could exceed 90%, which will have substantial ecological, economic, and human health consequences.

  20. A new Arctic 25-year Altimetric Sea-level Record (1992-2016) and Initial look at Arctic Sea Level Budget Closure

    OpenAIRE

    Andersen O.B., Passaro M., Benveniste J., Piccioni G.

    2016-01-01

    A new initiative within the ESA Sea Level Climate Change initiative (SL-cci) framework to improve the Arctic sea level record has been initiated as a combined effort to reprocess and retrack past altimetry to create a 25-year combined sea level record for sea level research studies. One of the objectives is to retracked ERS-2 dataset for the high latitudes based on the ALES retracking algorithm through adapting the ALES retracker for retracking of specular surfaces (leads). Secondly a reproce...

  1. Uncertainty in Twenty-First-Century CMIP5 Sea Level Projections

    Science.gov (United States)

    Little, Christopher M.; Horton, Radley M.; Kopp, Robert E.; Oppenheimer, Michael; Yip, Stan

    2015-01-01

    The representative concentration pathway (RCP) simulations included in phase 5 of the Coupled Model Intercomparison Project (CMIP5) quantify the response of the climate system to different natural and anthropogenic forcing scenarios. These simulations differ because of 1) forcing, 2) the representation of the climate system in atmosphere-ocean general circulation models (AOGCMs), and 3) the presence of unforced (internal) variability. Global and local sea level rise projections derived from these simulations, and the emergence of distinct responses to the four RCPs depend on the relative magnitude of these sources of uncertainty at different lead times. Here, the uncertainty in CMIP5 projections of sea level is partitioned at global and local scales, using a 164-member ensemble of twenty-first-century simulations. Local projections at New York City (NYSL) are highlighted. The partition between model uncertainty, scenario uncertainty, and internal variability in global mean sea level (GMSL) is qualitatively consistent with that of surface air temperature, with model uncertainty dominant for most of the twenty-first century. Locally, model uncertainty is dominant through 2100, with maxima in the North Atlantic and the Arctic Ocean. The model spread is driven largely by 4 of the 16 AOGCMs in the ensemble; these models exhibit outlying behavior in all RCPs and in both GMSL and NYSL. The magnitude of internal variability varies widely by location and across models, leading to differences of several decades in the local emergence of RCPs. The AOGCM spread, and its sensitivity to model exclusion and/or weighting, has important implications for sea level assessments, especially if a local risk management approach is utilized.

  2. The Offlap Break Position Vs Sea Level: A Discussion

    Science.gov (United States)

    Tropeano, M.; Pieri, P.; Pomar, L.; Sabato, L.

    Sedimentary lithosomes with subhorizontal topsets, basinward prograding foresets and subhorizontal bottomsets are common in the geologic record, and most of them display similar bedding architectures and/or seismic reflection patterns (i.e. Gylbert- type deltas and shelf wedges). Nevertheless, in shallow marine settings these bodies may form in distinct sedimentary environments and they result from different sed- imentary processes. The offlap break (topset edge) occurs in relation to the posi- tion of baselevel and two main groups of lithosomes can be differentiated with re- spect to the position of the offlap break within the shelf profile. The baselevel of the first group is the sea level (or lake level); the topsets are mainly composed by continental- or very-shallow-water sedimentary facies and the offlap break practi- cally corresponds to the shoreline. Exemples of these lithosomes are high-constructive deltas (river-dominated deltas) and prograding beaches. For the second group, base- level corresponds to the base of wave/tide traction, and their topsets are mostly composed by shoreface/nearshore deposits. Examples of these lithosomes are high- destructive deltas (wave/tide-dominated deltas) and infralittoral prograding wedges (i.e Hernandez-Molina et al., 2000). The offlap break corresponds to the shelf edge (shoreface edge), which is located at the transition between nearshore and offshore set- tings, where a terrace prodelta- or transition-slope may develop (Pomar &Tropeano, 2001). Two main problems derive from these alternative interpretations of shallow- marine seaward prograding lithosomes: 1) both in ancient sedimentary shallow-marine successios (showing seaward prograding foresets) and in high resolution seismic pro- files (showing shelf wedges), the offlap break is commonly considered to correspond to the sea-level (shoreline) and used to inferr paleo sea-level positions and to construct sea-level curves. Without a good facies control, this use of

  3. Past sea level changes along the western continental margins of India: Evidences from morphology of the sea bed

    Digital Repository Service at National Institute of Oceanography (India)

    Vora, K.H.

    -wide have been affected to a considerable extent by Pleistocene glaciations (Emery, 1968). The rate of sea-level rise has varied frequently and the sea-level still stands produced wave-cut terraces and platforms. In other words, the surface of a terrace... Merh (1992) while reviewing Quaternary sea level changes along India’s coasts observed that the Last Glacial Stage was a period of regression when the sea level went down to almost -150 m. With the advent of the Holocene, the sea started rising...

  4. Greenhouse effect, sea level rise, and coastal drainage systems

    Energy Technology Data Exchange (ETDEWEB)

    Titus, J G; Kuo, C Y; Gibbs, M J; LaRoche, T B; Webb, M K; Waddell, J O

    1987-01-01

    Increasing concentrations of carbon dioxide and other gases are expected to warm the earth several degrees in the next century, which would raise sea level a few feet and alter precipitation patterns. Both of these changes would have major impacts on the operation of coastal drainage systems. However, because sea level rise and climate change resulting from the greenhouse effect are still uncertain, most planners and engineers are ignoring the potential implications. Case studies of the potential impact on watersheds in Charleston, South Carolina, and Fort Walton Beach, Florida, suggest that the cost of designing a new system to accommodate a rise in sea level will sometimes be small compared with the retrofit cost that may ultimately be necessary if new systems are not designed for a rise. Rather than ignore the greenhouse effect until its consequences are firmly established, engineers and planners should evaluate whether it would be worthwhile to insure that new systems are not vulnerable to the risks of climate change and sea level rise.

  5. Integrating conservation costs into sea level rise adaptive conservation prioritization

    Directory of Open Access Journals (Sweden)

    Mingjian Zhu

    2015-07-01

    Full Text Available Biodiversity conservation requires strategic investment as resources for conservation are often limited. As sea level rises, it is important and necessary to consider both sea level rise and costs in conservation decision making. In this study, we consider costs of conservation in an integrated modeling process that incorporates a geomorphological model (SLAMM, species habitat models, and conservation prioritization (Zonation to identify conservation priorities in the face of landscape dynamics due to sea level rise in the Matanzas River basin of northeast Florida. Compared to conservation priorities that do not consider land costs in the analysis process, conservation priorities that consider costs in the planning process change significantly. The comparison demonstrates that some areas with high conservation values might be identified as lower priorities when integrating economic costs in the planning process and some areas with low conservation values might be identified as high priorities when considering costs in the planning process. This research could help coastal resources managers make informed decisions about where and how to allocate conservation resources more wisely to facilitate biodiversity adaptation to sea level rise.

  6. Sea Level Change and Coastal Climate Services: The Way Forward

    Directory of Open Access Journals (Sweden)

    Gonéri Le Cozannet

    2017-10-01

    Full Text Available For many climate change impacts such as drought and heat waves, global and national frameworks for climate services are providing ever more critical support to adaptation activities. Coastal zones are especially in need of climate services for adaptation, as they are increasingly threatened by sea level rise and its impacts, such as submergence, flooding, shoreline erosion, salinization and wetland change. In this paper, we examine how annual to multi-decadal sea level projections can be used within coastal climate services (CCS. To this end, we review the current state-of-the art of coastal climate services in the US, Australia and France, and identify lessons learned. More broadly, we also review current barriers in the development of CCS, and identify research and development efforts for overcoming barriers and facilitating their continued growth. The latter includes: (1 research in the field of sea level, coastal and adaptation science and (2 cross-cutting research in the area of user interactions, decision making, propagation of uncertainties and overall service architecture design. We suggest that standard approaches are required to translate relative sea level information into the forms required to inform the wide range of relevant decisions across coastal management, including coastal adaptation.

  7. Responding to changes in sea level: engineering implications

    National Research Council Canada - National Science Library

    National Research Council Staff; Marine Board; Commission on Engineering and Technical Systems; Division on Engineering and Physical Sciences; National Research Council

    1987-01-01

    ... Mean Sea Level Marine Board Commission on Engineering and Technical Systems National Research Council National Academy Press Washington, D.C. 1987 Copyrightthe cannot be not from book, paper however, version for formatting, original authoritative the typesetting-specific the as from created publication files XML from other this and of recom...

  8. Diurnal variations of serum erythropoietin at sea level and altitude

    DEFF Research Database (Denmark)

    Klausen, T; Poulsen, T D; Fogh-Andersen, N

    1996-01-01

    in 2, 3 diphosphoglycerate. After 64 h at altitude, six of the nine subjects had down-regulated their serum-EPO concentrations so that median values were three times above those at sea level. These six subjects had significant diurnal variations of serum-EPO concentration at sea level; the nadir......This study tested the hypothesis that the diurnal variations of serum-erythropoietin concentration (serum-EPO) observed in normoxia also exist in hypoxia. The study also attempted to investigate the regulation of EPO production during sustained hypoxia. Nine subjects were investigated at sea level...... and during 4 days at an altitude of 4350 m. Median sea level serum-EPO concentration was 6 (range 6-13) U.l-1. Serum-EPO concentration increased after 18 and 42 h at altitude, [58 (range 39-240) and 54 (range 36-340) U.l-1, respectively], and then decreased after 64 and 88 h at altitude [34 (range 18...

  9. Geomorphic expression of late Quaternary sea level changes along ...

    Indian Academy of Sciences (India)

    Department of Geology, Faculty of Science, M. S. University of Baroda, Vadodara 390 002, India. ∗ e-mail: ... referred to as miliolite limestone and shell lime- stone that form coastal ... the bed rocks and corresponding to the prevailing sea level.

  10. Guiding Users to Sea Level Change Data Through Content

    Science.gov (United States)

    Quach, N.; Abercrombie, S. P.; Boening, C.; Brennan, H. P.; Gill, K. M.; Greguska, F. R., III; Huang, T.; Jackson, R.; Larour, E. Y.; Shaftel, H.; Tenenbaum, L. F.; Zlotnicki, V.; Boeck, A.; Moore, B.; Moore, J.

    2017-12-01

    The NASA Sea Level Change Portal (https://sealevel.nasa.gov) is an immersive and innovative web portal for sea level change research that addresses the needs of diverse audiences, from scientists across disparate disciplines to the general public to policy makers and businesses. Since sea level change research involves vast amounts of data from multiple fields, it becomes increasingly important to come up with novel and effective ways to guide users to the data they need. News articles published on the portal contains links to relevant data. The Missions section highlights missions and projects as well as provide a logical grouping of the data. Tools available on the portal, such as the Data Analysis Tool, a data visualization and high-performance environment for sea level analysis, and the Virtual Earth System Laboratory, a 3D simulation application, describes and links to the source data. With over 30K Facebook followers and over 23K Twitter follower, the portal outreach team also leverages social media to guide users to relevant data. This presentation focuses on how the portal uses news articles, mission and project pages, tools, and social media to connect users to the data.

  11. Vulnerability of wastewater infrastructure of coastal cities to sea level ...

    African Journals Online (AJOL)

    This study investigates the vulnerability of the wastewater collection and disposal infrastructure (i.e. pipelines and manholes, pumping stations and wastewater treatment plants) to sea-level rise in eThekwini Municipality, South Africa. By using geographical information systems (GIS) and a multi-criteria analysis considering ...

  12. Measuring progress of the global sea level observing system

    Science.gov (United States)

    Woodworth, Philip L.; Aarup, Thorkild; Merrifield, Mark; Mitchum, Gary T.; Le Provost, Christian

    Sea level is such a fundamental parameter in the sciences of oceanography geophysics, and climate change, that in the mid-1980s, the Intergovernmental Oceanographic Commission (IOC) established the Global Sea Level Observing System (GLOSS). GLOSS was to improve the quantity and quality of data provided to the Permanent Service for Mean Sea Level (PSMSL), and thereby, data for input to studies of long-term sea level change by the Intergovernmental Panel on Climate Change (IPCC). It would also provide the key data needed for international programs, such as the World Ocean Circulation Experiment (WOCE) and later, the Climate Variability and Predictability Programme (CLIVAR).GLOSS is now one of the main observation components of the Joint Technical Commission for Oceanography and Marine Meteorology (JCOMM) of IOC and the World Meteorological Organization (WMO). Progress and deficiencies in GLOSS were presented in July to the 22nd IOC Assembly at UNESCO in Paris and are contained in the GLOSS Assessment Report (GAR) [IOC, 2003a].

  13. On the eigenperiods in the Tyrrhenian sea level oscillations

    International Nuclear Information System (INIS)

    Speich, S.; Mosetti, F.

    1988-01-01

    In this paper the eigenperiods of the Tyrrhenian sea are examined by an hydrodinamical model in two dimensions. The knowledge of these eigenperiods is important to evaluate the seiches that often appear, in some point or circumstance, stronger than the tides. This investigation is performed by energizing the basin through the Sardinia channel, in the same way as it was already done for the tides. This excitation simulates a large set of waves inducing oscillations inside the basin. The periods of the waves are narrow and their amplitude equal. An analogous method of investigation is that of the fluorescence. In addition, the results are compared with those previously obtained leaving the basin swinging, after having increased the sea level by an uniform displacement. The response of the bidimensional model agrees with that of a monodimensional one as far as possible; thus the last one can give useful information, also for a sea that does not have a channel shape, like the Tyrrhenian Sea. Nevertheless, this basin has other openings, besides the Sardinia channel, it seems that they do not influence the eigenperiod behaviour. This has been confirmed by performing the same computations over a sea 500m less deep: the uniform lowering of the sea surface is equivalent to close the four minor openings. The results carried out in this case agree with the previous one. Among all the periods pointed out by our investigation, one is always exhibited in every point and by each system. The period is that of 5.70h and it can be considered a fundamental mode of the Tyrrhenian Sea

  14. Sea-level and deep-sea-temperature variability over the past 5.3 million years.

    Science.gov (United States)

    Rohling, E J; Foster, G L; Grant, K M; Marino, G; Roberts, A P; Tamisiea, M E; Williams, F

    2014-04-24

    Ice volume (and hence sea level) and deep-sea temperature are key measures of global climate change. Sea level has been documented using several independent methods over the past 0.5 million years (Myr). Older periods, however, lack such independent validation; all existing records are related to deep-sea oxygen isotope (δ(18)O) data that are influenced by processes unrelated to sea level. For deep-sea temperature, only one continuous high-resolution (Mg/Ca-based) record exists, with related sea-level estimates, spanning the past 1.5 Myr. Here we present a novel sea-level reconstruction, with associated estimates of deep-sea temperature, which independently validates the previous 0-1.5 Myr reconstruction and extends it back to 5.3 Myr ago. We find that deep-sea temperature and sea level generally decreased through time, but distinctly out of synchrony, which is remarkable given the importance of ice-albedo feedbacks on the radiative forcing of climate. In particular, we observe a large temporal offset during the onset of Plio-Pleistocene ice ages, between a marked cooling step at 2.73 Myr ago and the first major glaciation at 2.15 Myr ago. Last, we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep-sea temperature.

  15. Evidence from the Seychelles of Last Interglacial Sea Level Oscillations

    Science.gov (United States)

    Vyverberg, K.; Dutton, A.; Dechnik, B.; Webster, J.; Zwartz, D.

    2014-12-01

    Several studies indicate that sea level oscillated during Marine Isotope Stage (MIS) 5e, but the details of these scenarios, including the number of sea level oscillations, are still debated. We lack a detailed understanding of the sensitivity of the large polar ice sheets to changes in temperature that could result in eustatic sea level oscillations. Because the Seychelles are located far from the margins of the Last Glacial Maximum northern hemisphere ice sheets, they have not been subjected to glacial isostatic adjustment, and have been tectonically stable since the Last Interglacial period; therefore, they provide a robust record of eustatic sea level during MIS 5e. All of the outcrops we examined contain unconformities and/or sharp transitions between facies, though the nature of these boundaries varies between sites. In some outcrops we observed a hardground comprising fine-grained, mollusc-rich sediment layer between distinct generations of in situ coralgal framework. In one outcrop, this succession was observed twice, where two generations of reef growth were each capped by a strongly indurated fine-grained, mollusc-rich sediment layer. At the site with the greatest vertical extent of outcrop, there is a marked difference in the taxonomic composition of the coral community above and below an unconformable surface, but the indurated fine-grained, sediment layer observed elsewhere was absent. Most of the other outcrops we studied contained a common succession of facies from in situ reef units overlain by cemented coral rubble. In two dated outcrops, the age of corals above and below the rubble layer are the same age. The hardgrounds and rubble layers may represent ephemeral exposure of the reef units during two drops in sea level. The inference of multiple meter-scale oscillations during the MIS 5e highstand indicates a more dynamic cryosphere than the present interglacial, although the climatic threshold for more volatile polar ice sheets is not yet clear.

  16. Uncertainty Quantification for Ice Sheet Science and Sea Level Projections

    Science.gov (United States)

    Boening, C.; Schlegel, N.; Limonadi, D.; Schodlok, M.; Seroussi, H. L.; Larour, E. Y.; Watkins, M. M.

    2017-12-01

    In order to better quantify uncertainties in global mean sea level rise projections and in particular upper bounds, we aim at systematically evaluating the contributions from ice sheets and potential for extreme sea level rise due to sudden ice mass loss. Here, we take advantage of established uncertainty quantification tools embedded within the Ice Sheet System Model (ISSM) as well as sensitivities to ice/ocean interactions using melt rates and melt potential derived from MITgcm/ECCO2. With the use of these tools, we conduct Monte-Carlo style sampling experiments on forward simulations of the Antarctic ice sheet, by varying internal parameters and boundary conditions of the system over both extreme and credible worst-case ranges. Uncertainty bounds for climate forcing are informed by CMIP5 ensemble precipitation and ice melt estimates for year 2100, and uncertainty bounds for ocean melt rates are derived from a suite of regional sensitivity experiments using MITgcm. Resulting statistics allow us to assess how regional uncertainty in various parameters affect model estimates of century-scale sea level rise projections. The results inform efforts to a) isolate the processes and inputs that are most responsible for determining ice sheet contribution to sea level; b) redefine uncertainty brackets for century-scale projections; and c) provide a prioritized list of measurements, along with quantitative information on spatial and temporal resolution, required for reducing uncertainty in future sea level rise projections. Results indicate that ice sheet mass loss is dependent on the spatial resolution of key boundary conditions - such as bedrock topography and melt rates at the ice-ocean interface. This work is performed at and supported by the California Institute of Technology's Jet Propulsion Laboratory. Supercomputing time is also supported through a contract with the National Aeronautics and Space Administration's Cryosphere program.

  17. Probabilistic reanalysis of twentieth-century sea-level rise.

    Science.gov (United States)

    Hay, Carling C; Morrow, Eric; Kopp, Robert E; Mitrovica, Jerry X

    2015-01-22

    Estimating and accounting for twentieth-century global mean sea level (GMSL) rise is critical to characterizing current and future human-induced sea-level change. Several previous analyses of tide gauge records--employing different methods to accommodate the spatial sparsity and temporal incompleteness of the data and to constrain the geometry of long-term sea-level change--have concluded that GMSL rose over the twentieth century at a mean rate of 1.6 to 1.9 millimetres per year. Efforts to account for this rate by summing estimates of individual contributions from glacier and ice-sheet mass loss, ocean thermal expansion, and changes in land water storage fall significantly short in the period before 1990. The failure to close the budget of GMSL during this period has led to suggestions that several contributions may have been systematically underestimated. However, the extent to which the limitations of tide gauge analyses have affected estimates of the GMSL rate of change is unclear. Here we revisit estimates of twentieth-century GMSL rise using probabilistic techniques and find a rate of GMSL rise from 1901 to 1990 of 1.2 ± 0.2 millimetres per year (90% confidence interval). Based on individual contributions tabulated in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, this estimate closes the twentieth-century sea-level budget. Our analysis, which combines tide gauge records with physics-based and model-derived geometries of the various contributing signals, also indicates that GMSL rose at a rate of 3.0 ± 0.7 millimetres per year between 1993 and 2010, consistent with prior estimates from tide gauge records.The increase in rate relative to the 1901-90 trend is accordingly larger than previously thought; this revision may affect some projections of future sea-level rise.

  18. Bipolar seesaw control on last interglacial sea level.

    Science.gov (United States)

    Marino, G; Rohling, E J; Rodríguez-Sanz, L; Grant, K M; Heslop, D; Roberts, A P; Stanford, J D; Yu, J

    2015-06-11

    Our current understanding of ocean-atmosphere-cryosphere interactions at ice-age terminations relies largely on assessments of the most recent (last) glacial-interglacial transition, Termination I (T-I). But the extent to which T-I is representative of previous terminations remains unclear. Testing the consistency of termination processes requires comparison of time series of critical climate parameters with detailed absolute and relative age control. However, such age control has been lacking for even the penultimate glacial termination (T-II), which culminated in a sea-level highstand during the last interglacial period that was several metres above present. Here we show that Heinrich Stadial 11 (HS11), a prominent North Atlantic cold episode, occurred between 135 ± 1 and 130 ± 2 thousand years ago and was linked with rapid sea-level rise during T-II. Our conclusions are based on new and existing data for T-II and the last interglacial that we collate onto a single, radiometrically constrained chronology. The HS11 cold episode punctuated T-II and coincided directly with a major deglacial meltwater pulse, which predominantly entered the North Atlantic Ocean and accounted for about 70 per cent of the glacial-interglacial sea-level rise. We conclude that, possibly in response to stronger insolation and CO2 forcing earlier in T-II, the relationship between climate and ice-volume changes differed fundamentally from that of T-I. In T-I, the major sea-level rise clearly post-dates Heinrich Stadial 1. We also find that HS11 coincided with sustained Antarctic warming, probably through a bipolar seesaw temperature response, and propose that this heat gain at high southern latitudes promoted Antarctic ice-sheet melting that fuelled the last interglacial sea-level peak.

  19. Estimating decadal variability in sea level from tide gauge records: An application to the North Sea

    NARCIS (Netherlands)

    Frederikse, Thomas; Riva, R.E.M.; Slobbe, Cornelis; Broerse, D.B.T.; Verlaan, Martin

    2016-01-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model by

  20. Estimating decadal variability in sea level from tide gauge records : An application to the North Sea

    NARCIS (Netherlands)

    Frederikse, T.; Riva, R.E.M.; Slobbe, D.C.; Broerse, D.B.T.; Verlaan, M.

    2016-01-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model

  1. Morphological changes within Florida Bay as a result of sea level rise

    Science.gov (United States)

    Holmes, C. W.

    2011-12-01

    Data from Florida Bay indicates that from 10,000 year BP to 6000 BP, the rate of sea level rise averaged about 10 mm/yr. The rate slowed at the end of this period flooding the shallow shelves surrounding the reef platforms of the western Atlantic. The relative flat South Florida shelf, because of its slight tilt to the southwest is an ideal local to assess the effects of this flooding. From 6000 BP to the present, numerous banks were formed within Florida Bay. A morphological model of bank formation based on the sea level oscillations was constructed from analysis of over 120 cores. These cores record sedimentological changes which are correlated to climatic events. In the central bay, the sediment accumulation was controlled by variations in rate of progressive sea-level rise. The Key West sea-level record shows that sea level has been rising incrementally over the last century. Between 1931 and 1950, sea level rose at a rate of 5 mm/yr. After 1950, it remained stable until 1971, when it again began to rise, but at a rate of 3 mm/yr. On the leeward side of mud banks, these variations resulted in shifts in sediment- accumulation rates, with accretion increasing during rising sea level and decreasing during stable periods. Between late 1970 and early 1972, a sharp jump in sea-level rise occurred that was approximately 10 cm higher than the preceding period. This jump coincided with a strongly positive North Atlantic Oscillation (NAO), a la Niña (negative ENSO), and a negative Pacific Decadal Oscillation (PDO). Water driven northward into Florida Bay eroded banks along the northern coastline, increased sediment accumulation in the northern lakes, and increased accretion rates on the banks. In addition to the sedimentological variations in the central portion of the bay, there was significant changes along the northern fringe. Around 1950, the northern fringe of the bay morphed from a fresh water environment to a marine environment. As a result, carbonate production

  2. Inter-annual sea level variability in the southern South China Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Soumya, M.; Vethamony, P.; Tkalich, P.

    (SCS) is one of the western marginal seas of the Pacific Ocean, surrounded by South China, Indo China Peninsula, Malaysian Peninsula, Philippines and Borneo Island. The SCS is a semi- enclosed basin connected to the western Pacific Ocean through Taiwan.... Sea level trend and variability in the Singapore Strait. Ocean Science, 9(2). Torrence, C. and Compo, G.P., 1998. A practical guide to wavelet analysis. Bulletin of the American Meteorological Society, 79(1): 61-78. Vargas‐Hernandez, J.M., Wijffels...

  3. Sea level and shoreline reconstructions for the Red Sea: isostatic and tectonic considerations and implications for hominin migration out of Africa

    Science.gov (United States)

    Lambeck, Kurt; Purcell, Anthony; Flemming, Nicholas. C.; Vita-Finzi, Claudio; Alsharekh, Abdullah M.; Bailey, Geoffrey N.

    2011-12-01

    observational evidence is consistent with tectonic and isostatic processes both operating over the past 300,000 years without requiring changes in the time averaged (over a few thousand years) tectonic rates. (v) Recent bathymetric data for the Bab al Mandab region have been compiled to confirm the location and depth of the sill controlling flow in and out of the Red Sea. Throughout the last 400,000 years the Red Sea has remained open to the Gulf of Aden with cross sectional areas at times of glacial maxima about 2% of that today. (vi) The minimum channel widths connecting the Red Sea to the Gulf of Aden at times of lowstand occur south of the Hanish Sill. The channels are less than 4 km wide and remain narrow for as long as local sea levels are below -50 m. This occurs for a number of sustained periods during the last two glacial cycles and earlier. (vii) Periods suitable for crossing between Africa and Arabia without requiring seaworthy boats or seafaring skills occurred periodically throughout the Pleistocene, particularly at times of favourable environmental climatic conditions that occurred during times of sea level lowstand.

  4. Geodetic infrastructure at the Barcelona harbour for sea level monitoring

    Science.gov (United States)

    Martinez-Benjamin, Juan Jose; Gili, Josep; Lopez, Rogelio; Tapia, Ana; Pros, Francesc; Palau, Vicenc; Perez, Begona

    2015-04-01

    The presentation is directed to the description of the actual geodetic infrastructure of Barcelona harbour with three tide gauges of different technologies for sea level determination and contribution to regional sea level rise and understanding past and present sea level rise in the Barcelona harbour. It is intended that the overall system will constitute a CGPS Station of the ESEAS (European Sea Level) and TIGA (GPS Tide Gauge Benchmark Monitoring) networks. At Barcelona harbour there is a MIROS radar tide gauge belonging to Puertos del Estado (Spanish Harbours).The radar sensor is over the water surface, on a L-shaped structure which elevates it a few meters above the quay shelf. 1-min data are transmitted to the ENAGAS Control Center by cable and then sent each 1 min to Puertos del Estado by e-mail. The information includes wave forescast (mean period, significant wave height, sea level, etc.This sensor also measures agitation and sends wave parameters each 20 min. There is a GPS station Leica Geosystems GRX1200 GG Pro and antenna AX 1202 GG. The Control Tower of the Port of Barcelona is situated in the North dike of the so-called Energy Pier in the Barcelona harbor (Spain). This tower has different kind of antennas for navigation monitoring and a GNSS permanent station. As the tower is founded in reclaimed land, and because its metallic structure, the 50 m building is subjected to diverse movements, including periodic fluctuations due to temperature changes. In this contribution the 2009, 2011, 2012, 2013 and 2014 the necessary monitoring campaigns are described. In the framework of a Spanish Space Project, the instrumentation of sea level measurements has been improved by providing the Barcelona site with a radar tide gauge Datamar 2000C from Geonica S.L. in June 2014 near an acoustic tide gauge from the Barcelona Harbour installed in 2013. Precision levelling has been made several times in the last two years because the tower is founded in reclaimed land and

  5. Radioactivity levels in some sediment samples from Red Sea and Baltic Sea

    International Nuclear Information System (INIS)

    Salahel Din, K.; Vesterbacka, P.

    2012-01-01

    Levels of 226, 228 Ra, 232 Th, 210 Pb, 210 Po and 40 K in sediments from four monitoring areas, El Hamraween and Ras El Behar (Red Sea (Egypt)) and LL3A and JML (Baltic Sea (Finland)), have been investigated using alpha and gamma spectrometry. The average activity concentrations were 238±4 Bq kg -1 ( 226 Ra), 215±11 Bq kg -1 ( 210 Pb) and 311±18 Bq kg -1 ( 210 Po) for El Hamraween area. In Ras El Behar area, the corresponding values were 16±0.4, 18±1 and 20±5 Bq kg -1 , respectively. The activity concentrations for 226 Ra, 210 Pb and 210 Po (uranium series) in El Hamraween bottom sediment are much high compared with those in Ras El Behar area, which indicates the enhanced levels due to the activities of phosphate mining and shipment operations in El Hamraween area. Excluding the influence of phosphate mining activities, it can be concluded that the levels of radioactivity in Baltic Sea sediments are higher than those in Red Sea sediments. (authors)

  6. Expression and localization of Aquaporin 1a in the sea-bass (Dicentrarchus labrax during ontogeny

    Directory of Open Access Journals (Sweden)

    Ivone eGiffard-Mena

    2011-07-01

    Full Text Available The successful establishment of a species in a given habitat depends on the ability of each of its developing stages to adapt to the environment. In order to understand this process we have studied the adaptation of a euryhaline fish, the sea-bass Dicentrarchus labrax, to various salinities during its ontogeny. The expression and localization of Aquaporin 1a (AQP1a mRNA and protein were determined in different osmoregulatory tissues. In larvae, the sites of AQP1a expression are variable and they shift according to age, implying functional changes. In juveniles after metamorphosis (D32-48 post hatch, 15 - 25 mm and in pre-adults, an increase in AQP1a transcript abundance was noted in the digestive tract, and the AQP1a location was observed in the intestine. In juveniles (D87-100 post hatch, 38 - 48 mm, the transcript levels of AQP1a in the digestive tract and in the kidney were higher in sea water than at lower salinity. These observations, in agreement with existing models, suggest that in sea water-acclimated fish, the imbibed water is absorbed via AQP1a through the digestive tract, particularly the intestine and the rectum. In addition, AQP1a may play a role in water reabsorption in the kidney. These mechanisms compensate dehydratation in sea water, and they contribute to the adaptation of juveniles to salinity changes during sea-lagoon migrations. These results contribute to the interpretation of the adaptation of populations to habitats where salinity varies.

  7. Sea urchin vault structure, composition, and differential localization during development

    Directory of Open Access Journals (Sweden)

    Dickey-Sims Carrie

    2005-02-01

    Full Text Available Abstract Background Vaults are intriguing ribonucleoprotein assemblies with an unknown function that are conserved among higher eukaryotes. The Pacific coast sea urchin, Strongylocentrotus purpuratus, is an invertebrate model organism that is evolutionarily closer to humans than Drosophila and C. elegans, neither of which possesses vaults. Here we compare the structures of sea urchin and mammalian vaults and analyze the subcellular distribution of vaults during sea urchin embryogenesis. Results The sequence of the sea urchin major vault protein (MVP was assembled from expressed sequence tags and genome traces, and the predicted protein was found to have 64% identity and 81% similarity to rat MVP. Sea urchin MVP includes seven ~50 residue repeats in the N-terminal half of the protein and a predicted coiled coil domain in the C-terminus, as does rat MVP. A cryoelectron microscopy (cryoEM reconstruction of isolated sea urchin vaults reveals the assembly to have a barrel-shaped external structure that is nearly identical to the rat vault structure. Analysis of the molecular composition of the sea urchin vault indicates that it contains components that may be homologs of the mammalian vault RNA component (vRNA and protein components (VPARP and TEP1. The sea urchin vault appears to have additional protein components in the molecular weight range of 14–55 kDa that might correspond to molecular contents. Confocal experiments indicate a dramatic relocalization of MVP from the cytoplasm to the nucleus during sea urchin embryogenesis. Conclusions These results are suggestive of a role for the vault in delivering macromolecules to the nucleus during development.

  8. Reassessment of 20th century global mean sea level rise

    Science.gov (United States)

    Dangendorf, Sönke; Marcos, Marta; Wöppelmann, Guy; Conrad, Clinton P.; Frederikse, Thomas; Riva, Riccardo

    2017-01-01

    The rate at which global mean sea level (GMSL) rose during the 20th century is uncertain, with little consensus between various reconstructions that indicate rates of rise ranging from 1.3 to 2 mm⋅y−1. Here we present a 20th-century GMSL reconstruction computed using an area-weighting technique for averaging tide gauge records that both incorporates up-to-date observations of vertical land motion (VLM) and corrections for local geoid changes resulting from ice melting and terrestrial freshwater storage and allows for the identification of possible differences compared with earlier attempts. Our reconstructed GMSL trend of 1.1 ± 0.3 mm⋅y−1 (1σ) before 1990 falls below previous estimates, whereas our estimate of 3.1 ± 1.4 mm⋅y−1 from 1993 to 2012 is consistent with independent estimates from satellite altimetry, leading to overall acceleration larger than previously suggested. This feature is geographically dominated by the Indian Ocean–Southern Pacific region, marking a transition from lower-than-average rates before 1990 toward unprecedented high rates in recent decades. We demonstrate that VLM corrections, area weighting, and our use of a common reference datum for tide gauges may explain the lower rates compared with earlier GMSL estimates in approximately equal proportion. The trends and multidecadal variability of our GMSL curve also compare well to the sum of individual contributions obtained from historical outputs of the Coupled Model Intercomparison Project Phase 5. This, in turn, increases our confidence in process-based projections presented in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. PMID:28533403

  9. Using environmental heterogeneity to plan for sea-level rise.

    Science.gov (United States)

    Hunter, Elizabeth A; Nibbelink, Nathan P

    2017-12-01

    Environmental heterogeneity is increasingly being used to select conservation areas that will provide for future biodiversity under a variety of climate scenarios. This approach, termed conserving nature's stage (CNS), assumes environmental features respond to climate change more slowly than biological communities, but will CNS be effective if the stage were to change as rapidly as the climate? We tested the effectiveness of using CNS to select sites in salt marshes for conservation in coastal Georgia (U.S.A.), where environmental features will change rapidly as sea level rises. We calculated species diversity based on distributions of 7 bird species with a variety of niches in Georgia salt marshes. Environmental heterogeneity was assessed across six landscape gradients (e.g., elevation, salinity, and patch area). We used 2 approaches to select sites with high environmental heterogeneity: site complementarity (environmental diversity [ED]) and local environmental heterogeneity (environmental richness [ER]). Sites selected based on ER predicted present-day species diversity better than randomly selected sites (up to an 8.1% improvement), were resilient to areal loss from SLR (1.0% average areal loss by 2050 compared with 0.9% loss of randomly selected sites), and provided habitat to a threatened species (0.63 average occupancy compared with 0.6 average occupancy of randomly selected sites). Sites selected based on ED predicted species diversity no better or worse than random and were not resilient to SLR (2.9% average areal loss by 2050). Despite the discrepancy between the 2 approaches, CNS is a viable strategy for conservation site selection in salt marshes because the ER approach was successful. It has potential for application in other coastal areas where SLR will affect environmental features, but its performance may depend on the magnitude of geological changes caused by SLR. Our results indicate that conservation planners that had heretofore excluded low

  10. Bayesian Statistical Analysis of Historical and Late Holocene Rates of Sea-Level Change

    Science.gov (United States)

    Cahill, Niamh; Parnell, Andrew; Kemp, Andrew; Horton, Benjamin

    2014-05-01

    of rise are continuously increasing. Analysis of the a global tide-gauge record (Church and White, 2011) indicated that the rate of sea-level rise increased continuously since 1880AD and is currently 2.57mm/yr (95% credible interval of 1.71 to 4.35mm/yr). Application of the model a proxy reconstruction from North Carolina (Kemp et al., 2011) indicated that the mean rate of rise in this locality since the middle of the 19th century (current rate of 2.66 mm/yr with a 95% credible interval of 1.29 to 4.59mm/yr) is in agreement with results from the tide gauge analysis and is unprecedented in at least the last 2000 years.

  11. Preparing for Sea-level Rise: Conflicts and Opportunities in Coastal Wetlands Coexisting with Infrastructure

    Science.gov (United States)

    Rodriguez, J. F.; Saco, P. M.; Sandi, S. G.; Saintilan, N.; Riccardi, G.

    2017-12-01

    Even though on a large scale the sustainability and resilience of coastal wetlands to sea-level rise depends on the slope of the landscape and a balance between the rates of soil accretion and the sea-level rise, local man-made flow disturbances can have comparable effects. Coastal infrastructure controlling flow in the wetlands can pose an additional constraint on the adaptive capacity of these ecosystems, but can also present opportunities for targeted flow management to increase their resilience. Coastal wetlands in SE Australia are heavily managed and typically present infrastructure including flow control devices. How these flow control structures are operated respond to different ecological conservation objectives (i.e. bird, frog or fish habitat) that can sometimes be mutually exclusive. For example, promoting mangrove establishment to enhance fish habitat results in saltmarsh decline thus affecting bird habitat. Moreover, sea-level rise will change hydraulic conditions in wetlands and may result in some flow control structures and strategies becoming obsolete or even counterproductive. In order to address these problems and in support of future management of flows in coastal wetlands, we have developed a predictive tool for long-term wetland evolution that incorporates the effects of infrastructure and other perturbations to the tidal flow within the wetland (i.e. vegetation resistance) and determines how these flow conditions affect vegetation establishment and survival. We use the model to support management and analyse different scenarios of sea-level rise and flow control measures aimed at preserving bird habitat. Our results show that sea-level rise affects the efficiency of management measures and in some cases may completely override their effect. It also shows the potential of targeted flow management to compensate for the effects of sea-level rise.

  12. Application of geo-spatial technologies in coastal vulnerability studies due to Sea Level Rise (SLR) along the Central Orissa Coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    ManiMurali, R.

    This chapter emphasizes the regional and local level coastal vulnerability studies due to sea level rise and the subsequent coastal inundation along the low-lying coastal areas using the advanced geo-spatial technologies. Natural hazards...

  13. Reconciling projections of the Antarctic contribution to sea level rise

    Science.gov (United States)

    Edwards, Tamsin; Holden, Philip; Edwards, Neil; Wernecke, Andreas

    2017-04-01

    Two recent studies of the Antarctic contribution to sea level rise this century had best estimates that differed by an order of magnitude (around 10 cm and 1 m by 2100). The first, Ritz et al. (2015), used a model calibrated with satellite data, giving a 5% probability of exceeding 30cm by 2100 for sea level rise due to Antarctic instability. The second, DeConto and Pollard (2016), used a model evaluated with reconstructions of palaeo-sea level. They did not estimate probabilities, but using a simple assumption here about the distribution shape gives up to a 5% chance of Antarctic contribution exceeding 2.3 m this century with total sea level rise approaching 3 m. If robust, this would have very substantial implications for global adaptation to climate change. How are we to make sense of this apparent inconsistency? How much is down to the data - does the past tell us we will face widespread and rapid Antarctic ice losses in the future? How much is due to the mechanism of rapid ice loss ('cliff failure') proposed in the latter paper, or other parameterisation choices in these low resolution models (GRISLI and PISM, respectively)? How much is due to choices made in the ensemble design and calibration? How do these projections compare with high resolution, grounding line resolving models such as BISICLES? Could we reduce the huge uncertainties in the palaeo-study? Emulation provides a powerful tool for understanding these questions and reconciling the projections. By describing the three numerical ice sheet models with statistical models, we can re-analyse the ensembles and re-do the calibrations under a common statistical framework. This reduces uncertainty in the PISM study because it allows massive sampling of the parameter space, which reduces the sensitivity to reconstructed palaeo-sea level values and also narrows the probability intervals because the simple assumption about distribution shape above is no longer needed. We present reconciled probabilistic

  14. A reconciled estimate of glacier contributions to sea level rise: 2003 to 2009.

    Science.gov (United States)

    Gardner, Alex S; Moholdt, Geir; Cogley, J Graham; Wouters, Bert; Arendt, Anthony A; Wahr, John; Berthier, Etienne; Hock, Regine; Pfeffer, W Tad; Kaser, Georg; Ligtenberg, Stefan R M; Bolch, Tobias; Sharp, Martin J; Hagen, Jon Ove; van den Broeke, Michiel R; Paul, Frank

    2013-05-17

    Glaciers distinct from the Greenland and Antarctic Ice Sheets are losing large amounts of water to the world's oceans. However, estimates of their contribution to sea level rise disagree. We provide a consensus estimate by standardizing existing, and creating new, mass-budget estimates from satellite gravimetry and altimetry and from local glaciological records. In many regions, local measurements are more negative than satellite-based estimates. All regions lost mass during 2003-2009, with the largest losses from Arctic Canada, Alaska, coastal Greenland, the southern Andes, and high-mountain Asia, but there was little loss from glaciers in Antarctica. Over this period, the global mass budget was -259 ± 28 gigatons per year, equivalent to the combined loss from both ice sheets and accounting for 29 ± 13% of the observed sea level rise.

  15. Interannual sea level variability in the Pearl River Estuary and its response to El Niño-Southern Oscillation

    Science.gov (United States)

    Wang, Linlin; Li, Qiang; Mao, Xian-zhong; Bi, Hongsheng; Yin, Peng

    2018-03-01

    The South China coast, especially the Pearl River Estuary (PRE) region, is prosperous and densely populated, but vulnerable to sea level changes. Sea level anomalies (SLA) during 1954-2012 from tide gauge station data and regional SLAs during 1993-2012 from satellite altimetry are analyzed and compare to the El Niño-Southern Oscillation (ENSO). Results show that sea level declines during El Niño events and rises during La Niña. Sea level in the PRE responds to ENSO with 3-month lag. The ENSO can cause sea level in the PRE to fluctuate from -8.70 to 8.11 cm. Sea level cycles of 3 and 5 years are related to ENSO. The ENSO mechanism affecting sea level in the PRE was analyzed by identifying dominant regional and local forces. Weak/strong SLAs in most El Niño/La Niña events may be attributed to less/more seawater transport driven by anomalously weak/strong north winds and local anomalously high/low sea level pressure. Wind-driven coastal current is the predominant factor. It generated coastal seawater volume transport along a 160 km wide cross section to decrease by 21.07% in a typical El Niño period (January 2010) and increase by 44.03% in a typical La Niña period (January 2011) as compared to an ENSO neutral situation (January 2013). Results of sea level rise and its potential mechanism provide insight for disaster protection during extreme El Niño/La Niña events.

  16. Return period estimates of extreme sea level along the east coast of India from numerical simulations

    Digital Repository Service at National Institute of Oceanography (India)

    Sindhu, B.; Unnikrishnan, A.S.

    . The simulated total sea level and the surge component were obtained for each event. The simulated peak levels showed good agreement with the observations available at few stations. The annual maxima of sea levels, extracted from the simulations, were fitted...

  17. Sea Level Forecasts Aggregated from Established Operational Systems

    Directory of Open Access Journals (Sweden)

    Andy Taylor

    2017-08-01

    Full Text Available A system for providing routine seven-day forecasts of sea level observable at tide gauge locations is described and evaluated. Forecast time series are aggregated from well-established operational systems of the Australian Bureau of Meteorology; although following some adjustments these systems are only quasi-complimentary. Target applications are routine coastal decision processes under non-extreme conditions. The configuration aims to be relatively robust to operational realities such as version upgrades, data gaps and metadata ambiguities. Forecast skill is evaluated against hourly tide gauge observations. Characteristics of the bias correction term are demonstrated to be primarily static in time, with time varying signals showing regional coherence. This simple approach to exploiting existing complex systems can offer valuable levels of skill at a range of Australian locations. The prospect of interpolation between observation sites and exploitation of lagged-ensemble uncertainty estimates could be meaningfully pursued. Skill characteristics define a benchmark against which new operational sea level forecasting systems can be measured. More generally, an aggregation approach may prove to be optimal for routine sea level forecast services given the physically inhomogeneous processes involved and ability to incorporate ongoing improvements and extensions of source systems.

  18. Sea level variability in the Arctic Ocean observed by satellite altimetry

    OpenAIRE

    Prandi, P.; Ablain, M.; Cazenave, A.; Picot, N.

    2012-01-01

    We investigate sea level variability in the Arctic Ocean from observations. Variability estimates are derived both at the basin scale and on smaller local spatial scales. The periods of the signals studied vary from high frequency (intra-annual) to long term trends. We also investigate the mechanisms responsible for the observed variability. Different data types are used, the main one being a recent reprocessing of satellite altimetry data...

  19. Sea Level Rise Impacts on Wastewater Treatment Systems Along the U.S. Coasts

    Science.gov (United States)

    Hummel, Michelle A.; Berry, Matthew S.; Stacey, Mark T.

    2018-04-01

    As sea levels rise, coastal communities will experience more frequent and persistent nuisance flooding, and some low-lying areas may be permanently inundated. Critical components of lifeline infrastructure networks in these areas are also at risk of flooding, which could cause significant service disruptions that extend beyond the flooded zone. Thus, identifying critical infrastructure components that are exposed to sea level rise is an important first step in developing targeted investment in protective actions and enhancing the overall resilience of coastal communities. Wastewater treatment plants are typically located at low elevations near the coastline to minimize the cost of collecting consumed water and discharging treated effluent, which makes them particularly susceptible to coastal flooding. For this analysis, we used geographic information systems to assess the exposure of wastewater infrastructure to various sea level rise projections at the national level. We then estimated the number of people who would lose wastewater services, which could be more than five times as high as previous predictions of the number of people at risk of direct flooding due to sea level rise. We also performed a regional comparison of wastewater exposure to marine and groundwater flooding in the San Francisco Bay Area. Overall, this analysis highlights the widespread exposure of wastewater infrastructure in the United States and demonstrates that local disruptions to infrastructure networks may have far-ranging impacts on areas that do not experience direct flooding.

  20. Sea level rise impacts on wastewater treatment systems along the U.S. coasts

    Science.gov (United States)

    Hummel, M.; Berry, M.; Stacey, M. T.

    2017-12-01

    As sea levels rise, coastal communities will experience more frequent and persistent nuisance flooding, and some low-lying areas may be permanently inundated. Critical components of lifeline infrastructure networks in these areas are also at risk of flooding, which could cause significant service disruptions that extend beyond the flooded zone. Thus, identifying critical infrastructure components that are vulnerable to sea level rise is an important first step in developing targeted investment in protective actions and enhancing the overall resilience of coastal communities. Wastewater treatment plants are typically located at low elevations near the coastline to minimize the cost of collecting consumed water and discharging treated effluent, which makes them particularly susceptible to coastal flooding. For this analysis, we used geographic information systems to assess the vulnerability of wastewater infrastructure to various sea level rise projections at the national level. We then estimated the number of people who would lose wastewater services, which could be more than three times as high as previous predictions of the number of people at risk of direct flooding due to sea level rise. We also considered several case studies of wastewater infrastructure in mid-sized cities to determine how topography and system configuration (centralized versus distributed) impact vulnerability. Overall, this analysis highlights the widespread vulnerability of wastewater infrastructure in the U.S. and demonstrates that local disruptions to infrastructure networks may have far-ranging impacts on areas that do not experience direct flooding.

  1. Flooded! An Investigation of Sea-Level Rise in a Changing Climate

    Science.gov (United States)

    Gillette, Brandon; Hamilton, Cheri

    2011-01-01

    Explore how melting ice sheets affect global sea levels. Sea-level rise (SLR) is a rise in the water level of the Earth's oceans. There are two major kinds of ice in the polar regions: sea ice and land ice. Land ice contributes to SLR and sea ice does not. This article explores the characteristics of sea ice and land ice and provides some hands-on…

  2. Sandy berm and beach-ridge formation in relation to extreme sea-levels

    DEFF Research Database (Denmark)

    Bendixen, Mette; Clemmensen, Lars B; Kroon, Aart

    2013-01-01

    The formation of berms and their transformation into beach ridges in a micro-tidal environment is coupled to wave run-up and overtopping during extreme sea levels. A straight-forward comparison between extreme sea levels due to storm-surges and active berm levels is impossible in the semi...... prograding spit on the south-eastern Baltic shores of Zealand, Denmark. The modern, sandy beach at this location consists of a beachface with a shallow incipient berm, a mature berm, and a dune-covered beach ridge. It borders a beach-ridge plain to the west, where more than 20 N–S oriented beach ridges...... and swales are present. Measured water-level data from 1991 to 2012 and topographical observations, carried out during fair weather period and during a storm event, provided the basis for a conceptual model exhibiting berm formation and transformation into the local beach-ridge system. The character...

  3. Estimates of the Economic Effects of Sea Level Rise

    International Nuclear Information System (INIS)

    Darwin, R.F.; Tol, R.S.J.

    2001-01-01

    Regional estimates of direct cost (DC) are commonly used to measure the economic damages of sea level rise. Such estimates suffer from three limitations: (1) values of threatened endowments are not well known, (2) loss of endowments does not affect consumer prices, and (3) international trade is disregarded. Results in this paper indicate that these limitations can significantly affect economic assessments of sea level rise. Current uncertainty regarding endowment values (as reflected in two alternative data sets), for example, leads to a 17 percent difference in coastal protection, a 36 percent difference in the amount of land protected, and a 36 percent difference in DC globally. Also, global losses in equivalent variation (EV), a welfare measure that accounts for price changes, are 13 percent higher than DC estimates. Regional EV losses may be up to 10 percent lower than regional DC, however, because international trade tends to redistribute losses from regions with relatively high damages to regions with relatively low damages. 43 refs

  4. Sea level reconstruction from satellite altimetry and tide gauge data

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

    2012-01-01

    Ocean satellite altimetry has provided global sets of sea level data for the last two decades, allowing determination of spatial patterns in global sea level. For reconstructions going back further than this period, tide gauge data can be used as a proxy. We examine different methods of combining...... for better sensitivity analysis with respect to spatial distribution, and tide gauge data are available around the Arctic Ocean, which may be important for a later high-latitude reconstruction....... satellite altimetry and tide gauge data using optimal weighting of tide gauge data, linear regression and EOFs, including automatic quality checks of the tide gauge time series. We attempt to augment the model using various proxies such as climate indices like the NAO and PDO, and investigate alternative...

  5. The Greenlandic sea areas and activity level up to 2025

    DEFF Research Database (Denmark)

    Jakobsen, Uffe; í Dali, Birita

    2016-01-01

    , petroleum activity, tourism and research/government activity. The last chapter is devoted to summarizing findings about the current developed activity level in the High North sea and coastal regions and the estimated activity level up to 2025. Possible implications for the preparedness system in the High....... It includes an overview of types of vessels and other objects involved in different activities, and the volume of traffic connected to different types of activities, such as fisheries, petroleum, tourism, navy and research. Furthermore, this report estimates the maritime activity level in the area the next...

  6. The global coastline dataset: the observed relation between erosion and sea-level rise

    Science.gov (United States)

    Donchyts, G.; Baart, F.; Luijendijk, A.; Hagenaars, G.

    2017-12-01

    Erosion of sandy coasts is considered one of the key risks of sea-level rise. Because sandy coastlines of the world are often highly populated, erosive coastline trends result in risk to populations and infrastructure. Most of our understanding of the relation between sea-level rise and coastal erosion is based on local or regional observations and generalizations of numerical and physical experiments. Until recently there was no reliable global scale assessment of the location of sandy coasts and their rate of erosion and accretion. Here we present the global coastline dataset that covers erosion indicators on a local scale with global coverage. The dataset uses our global coastline transects grid defined with an alongshore spacing of 250 m and a cross shore length extending 1 km seaward and 1 km landward. This grid matches up with pre-existing local grids where available. We present the latest results on validation of coastal-erosion trends (based on optical satellites) and classification of sandy versus non-sandy coasts. We show the relation between sea-level rise (based both on tide-gauges and multi-mission satellite altimetry) and observed erosion trends over the last decades, taking into account broken-coastline trends (for example due to nourishments).An interactive web application presents the publicly-accessible results using a backend based on Google Earth Engine. It allows both researchers and stakeholders to use objective estimates of coastline trends, particularly when authoritative sources are not available.

  7. The Future of GLOSS Sea Level Data Archaeology

    Science.gov (United States)

    Jevrejeva, S.; Bradshaw, E.; Tamisiea, M. E.; Aarup, T.

    2014-12-01

    Long term climate records are rare, consisting of unique and unrepeatable measurements. However, data do exist in analogue form in archives, libraries and other repositories around the world. The Global Sea Level Observing System (GLOSS) Group of Experts aims to provide advice on locating hidden tide gauge data, scanning and digitising records and quality controlling the resulting data. Long sea level data time series are used in Intergovernmental Panel on Climate Change (IPCC) assessment reports and climate studies, in oceanography to study changes in ocean currents, tides and storm surges, in geodesy to establish national datum and in geography and geology to monitor coastal land movement. GLOSS has carried out a number of data archaeology activities over the past decade, which have mainly involved sending member organisations questionnaires on their repositories. The Group of Experts is now looking at future developments in sea level data archaeology and how new technologies coming on line could be used by member organisations to make data digitisation and transcription more efficient. Analogue tide data comes in two forms charts, which record the continuous measurements made by an instrument, usually via a pen trace on paper ledgers containing written values of observations The GLOSS data archaeology web pages will provide a list of software that member organisations have reported to be suitable for the automatic digitisation of tide gauge charts. Transcribing of ledgers has so far proved more labour intensive and is usually conducted by people entering numbers by hand. GLOSS is exploring using Citizen Science techniques, such as those employed by the Old Weather project, to improve the efficiency of transcribing ledgers. The Group of Experts is also looking at recent advances in Handwritten Text Recognition (HTR) technology, which mainly relies on patterns in the written word, but could be adapted to work with the patterns inherent in sea level data.

  8. Portrait of a Warming Ocean and Rising Sea Levels: Trend of Sea Level Change 1993-2008

    Science.gov (United States)

    2008-01-01

    Warming water and melting land ice have raised global mean sea level 4.5 centimeters (1.7 inches) from 1993 to 2008. But the rise is by no means uniform. This image, created with sea surface height data from the Topex/Poseidon and Jason-1 satellites, shows exactly where sea level has changed during this time and how quickly these changes have occurred. It's also a road map showing where the ocean currently stores the growing amount of heat it is absorbing from Earth's atmosphere and the heat it receives directly from the Sun. The warmer the water, the higher the sea surface rises. The location of heat in the ocean and its movement around the globe play a pivotal role in Earth's climate. Light blue indicates areas in which sea level has remained relatively constant since 1993. White, red, and yellow are regions where sea levels have risen the most rapidly up to 10 millimeters per year and which contain the most heat. Green areas have also risen, but more moderately. Purple and dark blue show where sea levels have dropped, due to cooler water. The dramatic variation in sea surface heights and heat content across the ocean are due to winds, currents and long-term changes in patterns of circulation. From 1993 to 2008, the largest area of rapidly rising sea levels and the greatest concentration of heat has been in the Pacific, which now shows the characteristics of the Pacific Decadal Oscillation (PDO), a feature that can last 10 to 20 years or even longer. In this 'cool' phase, the PDO appears as a horseshoe-shaped pattern of warm water in the Western Pacific reaching from the far north to the Southern Ocean enclosing a large wedge of cool water with low sea surface heights in the eastern Pacific. This ocean/climate phenomenon may be caused by wind-driven Rossby waves. Thousands of kilometers long, these waves move from east to west on either side of the equator changing the distribution of water mass and heat. This image of sea level trend also reveals a significant

  9. How mangrove forests adjust to rising sea level

    Science.gov (United States)

    Krauss, Ken W.; McKee, Karen L.; Lovelock, Catherine E.; Cahoon, Donald R.; Saintilan, Neil; Reef, Ruth; Chen, Luzhen

    2014-01-01

    Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to sea-level rise. To persist, mangrove ecosystems must adjust to rising sea level by building vertically or become submerged. Mangroves may directly or indirectly influence soil accretion processes through the production and accumulation of organic matter, as well as the trapping and retention of mineral sediment. In this review, we provide a general overview of research on mangrove elevation dynamics, emphasizing the role of the vegetation in maintaining soil surface elevations (i.e. position of the soil surface in the vertical plane). We summarize the primary ways in which mangroves may influence sediment accretion and vertical land development, for example, through root contributions to soil volume and upward expansion of the soil surface. We also examine how hydrological, geomorphological and climatic processes may interact with plant processes to influence mangrove capacity to keep pace with rising sea level. We draw on a variety of studies to describe the important, and often under-appreciated, role that plants play in shaping the trajectory of an ecosystem undergoing change.

  10. Mangrove Sedimentation and Response to Relative Sea-Level Rise.

    Science.gov (United States)

    Woodroffe, C D; Rogers, K; McKee, K L; Lovelock, C E; Mendelssohn, I A; Saintilan, N

    2016-01-01

    Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions, related primarily to elevation and hydroperiod, influence mangrove distributions; this review considers how these distributions change over time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks, and tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon but also contain paleoenvironmental records of adjustments to past sea-level changes. Radiometric dating indicates long-term sedimentation, whereas measurements made using surface elevation tables and marker horizons provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative sea-level rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative sea-level rise. However, many human pressures threaten mangroves, resulting in a continuing decline in their extent throughout the tropics.

  11. Mangrove sedimentation and response to relative sea-level rise

    Science.gov (United States)

    Woodroffe, CD; Rogers, K.; Mckee, Karen L.; Lovelock, CE; Mendelssohn, IA; Saintilan, N.

    2016-01-01

    Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions influence mangrove distributions, primarily related to elevation and hydroperiod; this review considers how these adjust through time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks; tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon, but also contain paleoenvironmental records of adjustments to past sea-level changes. Radiometric dating indicates long-term sedimentation, whereas Surface Elevation Table-Marker Horizon measurements (SET-MH) provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative sea-level rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative sea-level rise. However, many human pressures threaten mangroves, resulting in continuing decline in their extent throughout the tropics.

  12. Detection of human influence on sea-level pressure.

    Science.gov (United States)

    Gillett, Nathan P; Zwiers, Francis W; Weaver, Andrew J; Stott, Peter A

    2003-03-20

    Greenhouse gases and tropospheric sulphate aerosols--the main human influences on climate--have been shown to have had a detectable effect on surface air temperature, the temperature of the free troposphere and stratosphere and ocean temperature. Nevertheless, the question remains as to whether human influence is detectable in any variable other than temperature. Here we detect an influence of anthropogenic greenhouse gases and sulphate aerosols in observations of winter sea-level pressure (December to February), using combined simulations from four climate models. We find increases in sea-level pressure over the subtropical North Atlantic Ocean, southern Europe and North Africa, and decreases in the polar regions and the North Pacific Ocean, in response to human influence. Our analysis also indicates that the climate models substantially underestimate the magnitude of the sea-level pressure response. This discrepancy suggests that the upward trend in the North Atlantic Oscillation index (corresponding to strengthened westerlies in the North Atlantic region), as simulated in a number of global warming scenarios, may be too small, leading to an underestimation of the impacts of anthropogenic climate change on European climate.

  13. Future increases in Arctic precipitation linked to local evaporation and sea-ice retreat.

    Science.gov (United States)

    Bintanja, R; Selten, F M

    2014-05-22

    Precipitation changes projected for the end of the twenty-first century show an increase of more than 50 per cent in the Arctic regions. This marked increase, which is among the highest globally, has previously been attributed primarily to enhanced poleward moisture transport from lower latitudes. Here we use state-of-the-art global climate models to show that the projected increases in Arctic precipitation over the twenty-first century, which peak in late autumn and winter, are instead due mainly to strongly intensified local surface evaporation (maximum in winter), and only to a lesser degree due to enhanced moisture inflow from lower latitudes (maximum in late summer and autumn). Moreover, we show that the enhanced surface evaporation results mainly from retreating winter sea ice, signalling an amplified Arctic hydrological cycle. This demonstrates that increases in Arctic precipitation are firmly linked to Arctic warming and sea-ice decline. As a result, the Arctic mean precipitation sensitivity (4.5 per cent increase per degree of temperature warming) is much larger than the global value (1.6 to 1.9 per cent per kelvin). The associated seasonally varying increase in Arctic precipitation is likely to increase river discharge and snowfall over ice sheets (thereby affecting global sea level), and could even affect global climate through freshening of the Arctic Ocean and subsequent modulations of the Atlantic meridional overturning circulation.

  14. Sea-level and solid-Earth deformation feedbacks in ice sheet modelling

    Science.gov (United States)

    Konrad, Hannes; Sasgen, Ingo; Klemann, Volker; Thoma, Malte; Grosfeld, Klaus; Martinec, Zdeněk

    2014-05-01

    The interactions of ice sheets with the sea level and the solid Earth are important factors for the stability of the ice shelves and the tributary inland ice (e.g. Thomas and Bentley, 1978; Gomez et al, 2012). First, changes in ice extent and ice thickness induce viscoelastic deformation of the Earth surface and Earth's gravity field. In turn, global and local changes in sea level and bathymetry affect the grounding line and, subsequently, alter the ice dynamic behaviour. Here, we investigate these feedbacks for a synthetic ice sheet configuration as well as for the Antarctic ice sheet using a three-dimensional thermomechanical ice sheet and shelf model, coupled to a viscoelastic solid-Earth and gravitationally self-consistent sea-level model. The respective ice sheet undergoes a forcing from rising sea level, warming ocean, and/or changing surface mass balance. The coupling is realized by exchanging ice thickness, Earth surface deformation and sea level periodically. We apply several sets of viscoelastic Earth parameters to our coupled model, e.g. simulating a low-viscous upper mantle present at the Antarctic Peninsula (Ivins et al., 2011). Special focus of our study lies on the evolution of Earth surface deformation and local sea level changes, as well as on the accompanying grounding line evolution. N. Gomez, D. Pollard, J. X. Mitrovica, P. Huybers, and P. U. Clark 2012. Evolution of a coupled marine ice sheet-sea level model, J. Geophys. Res., 117, F01013, doi:10.1029/2011JF002128. E. R. Ivins, M. M. Watkins, D.-N. Yuan, R. Dietrich, G. Casassa, and A. Rülke 2011. On-land ice loss and glacial isostatic adjustment at the Drake Passage: 2003-2009, J. Geophys. Res. 116, B02403, doi: 10.1029/2010JB007607 R. H. Thomas and C. R. Bentley 1978. A model for Holocene retreat of the West Antarctic Ice Sheet, Quaternary Research, 10 (2), pages 150-170, doi: 10.1016/0033-5894(78)90098-4.

  15. Observed Sea-Level Changes along the Norwegian Coast

    Directory of Open Access Journals (Sweden)

    Kristian Breili

    2017-07-01

    Full Text Available Norway’s national sea level observing system consists of an extensive array of tide gauges, permanent GNSS stations, and lines of repeated levelling. Here, we make use of this observation system to calculate relative sea-level rates and rates corrected for glacial isostatic adjustment (GIA along the Norwegian coast for three different periods, i.e., 1960 to 2010, 1984 to 2014, and 1993 to 2016. For all periods, the relative sea-level rates show considerable spatial variations that are largely due to differences in vertical land motion due to GIA. The variation is reduced by applying corrections for vertical land motion and associated gravitational effects on sea level. For 1960 to 2010 and 1984 to 2014, the coastal average GIA-corrected rates for Norway are 2.0 ± 0.6 mm/year and 2.2 ± 0.6 mm/year, respectively. This is close to the rate of global sea-level rise for the same periods. For the most recent period, 1993 to 2016, the GIA-corrected coastal average is 3.5 ± 0.6 mm/year and 3.2 ± 0.6 mm/year with and without inverse barometer (IB corrections, respectively, which is significantly higher than for the two earlier periods. For 1993 to 2016, the coastal average IB-corrected rates show broad agreement with two independent sets of altimetry. This suggests that there is no systematic error in the vertical land motion corrections applied to the tide-gauge data. At the same time, altimetry does not capture the spatial variation identified in the tide-gauge records. This could be an effect of using altimetry observations off the coast instead of directly at each tide gauge. Finally, we note that, owing to natural variability in the climate system, our estimates are highly sensitive to the selected study period. For example, using a 30-year moving window, we find that the estimated rates may change by up to 1 mm/year when shifting the start epoch by only one year.

  16. Sea level and global ice volumes from the Last Glacial Maximum to the Holocene.

    Science.gov (United States)

    Lambeck, Kurt; Rouby, Hélène; Purcell, Anthony; Sun, Yiying; Sambridge, Malcolm

    2014-10-28

    The major cause of sea-level change during ice ages is the exchange of water between ice and ocean and the planet's dynamic response to the changing surface load. Inversion of ∼1,000 observations for the past 35,000 y from localities far from former ice margins has provided new constraints on the fluctuation of ice volume in this interval. Key results are: (i) a rapid final fall in global sea level of ∼40 m in sea level, the main phase of deglaciation occurred from ∼16.5 ka BP to ∼8.2 ka BP at an average rate of rise of 12 m⋅ka(-1) punctuated by periods of greater, particularly at 14.5-14.0 ka BP at ≥40 mm⋅y(-1) (MWP-1A), and lesser, from 12.5 to 11.5 ka BP (Younger Dryas), rates; (iv) no evidence for a global MWP-1B event at ∼11.3 ka BP; and (v) a progressive decrease in the rate of rise from 8.2 ka to ∼2.5 ka BP, after which ocean volumes remained nearly constant until the renewed sea-level rise at 100-150 y ago, with no evidence of oscillations exceeding ∼15-20 cm in time intervals ≥200 y from 6 to 0.15 ka BP.

  17. The Potential Effect of Sea Level Rise on Coastal Property Values

    Science.gov (United States)

    O'Donnell, J.

    2015-12-01

    It is well established that one consequence of increasing global sea level is that the frequency of flooding at low-lying coastal sites will increase. We review recent evidence that the effects coastal geometry will create substantial spatial variations in the changes in flooding frequency with scales of order 100km. Using a simple model of the evolution of coastal property values we demonstrate that a consequence of sea level rise is that the appreciation of coastal properties will peak, and then decline relative to higher properties. The time when the value reach a maximum is shown to depend upon the demand for the coastal property, and the local rate of change of flooding frequency due to sea level rise. The simple model is then extended to include, in an elementary manner, the effects on the value of adjacent but higher properties. We show that the effect of increased flooding frequency of the lower properties leads to an accelerated appreciation of the value of upland properties and an accelerated decline in the value of the coastal properties. We then provide some example calculations for selected sites. We conclude with a discussion of comparisons of the prediction of the analyses to recent data, and then comments on the impact of sea level rise on tax base of coastal communities.

  18. Estimating decadal variability in sea level from tide gauge records: An application to the North Sea

    OpenAIRE

    Frederikse, Thomas; Riva, R.E.M.; Slobbe, Cornelis; Broerse, D.B.T.; Verlaan, Martin

    2016-01-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model by using a Kalman filter. The model consists of a time-varying trend and seasonal cycle, and variability induced by several physical processes, such as wind, atmospheric pressure changes and teleconne...

  19. The magnitude of a mid-Holocene sea-level highstand in the Strait of Makassar

    NARCIS (Netherlands)

    Mann, T.; Rovere, A.; Schöne, T.; Klicpera, A.; Stocchi, P.; Lukman, M.; Westphal, H.

    2016-01-01

    Knowledge on the timing andmagnitude of past sea-level changes is essential to understandmodern and futuresea-level variability.Holocene sea-level data fromliterature on thewest coast of Sulawesi, central Indonesia, suggestthat this region experienced two relative sea-level highstands over the last

  20. Integrating Non-Tidal Sea Level data from altimetry and tide gauges for coastal sea level prediction

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Andersen, Ole Baltazar; Knudsen, Per

    2012-01-01

    The main objective of this paper is to integrate Non-Tidal Sea Level (NSL) from the joint TOPEX, Jason-1 and Jason-2 satellite altimetry with tide gauge data at the west and north coast of the United Kingdom for coastal sea level prediction. The temporal correlation coefficient between altimetric...... NSLs and tide gauge data reaches a maximum higher than 90% for each gauge. The results show that the multivariate regression approach can efficiently integrate the two types of data in the coastal waters of the area. The Multivariate Regression Model is established by integrating the along-track NSL...... from the joint TOPEX/Jason-1/Jason-2 altimeters with that from eleven tide gauges. The model results give a maximum hindcast skill of 0.95, which means maximum 95% of NSL variance can be explained by the model. The minimum Root Mean Square Error (RMSe) between altimetric observations and model...

  1. Prediction of South China sea level using seasonal ARIMA models

    Science.gov (United States)

    Fernandez, Flerida Regine; Po, Rodolfo; Montero, Neil; Addawe, Rizavel

    2017-11-01

    Accelerating sea level rise is an indicator of global warming and poses a threat to low-lying places and coastal countries. This study aims to fit a Seasonal Autoregressive Integrated Moving Average (SARIMA) model to the time series obtained from the TOPEX and Jason series of satellite radar altimetries of the South China Sea from the year 2008 to 2015. With altimetric measurements taken in a 10-day repeat cycle, monthly averages of the satellite altimetry measurements were taken to compose the data set used in the study. SARIMA models were then tried and fitted to the time series in order to find the best-fit model. Results show that the SARIMA(1,0,0)(0,1,1)12 model best fits the time series and was used to forecast the values for January 2016 to December 2016. The 12-month forecast using SARIMA(1,0,0)(0,1,1)12 shows that the sea level gradually increases from January to September 2016, and decreases until December 2016.

  2. Gap Filling of Daily Sea Levels by Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Lyubka Pashova

    2013-06-01

    Full Text Available In the recent years, intelligent methods as artificial neural networks are successfully applied for data analysis from different fields of the geosciences. One of the encountered practical problems is the availability of gaps in the time series that prevent their comprehensive usage for the scientific and practical purposes. The article briefly describes two types of the artificial neural network (ANN architectures - Feed-Forward Backpropagation (FFBP and recurrent Echo state network (ESN. In some cases, the ANN can be used as an alternative on the traditional methods, to fill in missing values in the time series. We have been conducted several experiments to fill the missing values of daily sea levels spanning a 5-years period using both ANN architectures. A multiple linear regression for the same purpose has been also applied. The sea level data are derived from the records of the tide gauge Burgas, which is located on the western Black Sea coast. The achieved results have shown that the performance of ANN models is better than that of the classical one and they are very promising for the real-time interpolation of missing data in the time series.

  3. Changes in Holocene relative sea-level and coastal morphology

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Sander, Lasse; Clemmensen, Lars B

    2015-01-01

    Changes in relative sea-level (RSL) during the Holocene are reconstructed based on ground-penetrating radar (GPR) data collected across a raised beach ridge system on the island of Samsø, Denmark. The internal architecture of the beach ridge and swale deposits is divided into characteristic radar...... ridge progradation through time. The vertical levels of identified downlap points are combined with an age model based on optically stimulated luminescence-dated samples to reconstruct RSL for the past c. 5000 years. Overall, the reconstruction shows that the period between c. 4800 and 3800 yr BP...

  4. Confidence and sensitivity of sea-level reconstructions

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde

    For the last two decades, satellite altimetry has provided a near-global view of spatial and temporal patterns in sea surface height (SSH). When combined with records from tide gauges, a historical reconstruction of sea level can be obtained; while tide gauge records span up to 200 years back...... nature of the data fields. We examine the sensitivity of a reconstruction with respect to the length of calibration time series, and the spatial distribution of tide gauges or other proxy data. In addition, we consider the eect of isolating certain physical phenomena (e.g. ENSO) and annual signals...... and modelling these outside the reconstruction. The implementation is currently based on data from compound satellite datasets (i.e., two decades of altimetry), and the Simple Ocean Data Assimilation (SODA) model, an existing reconstruction, where a calibration period can be easily extracted and our model...

  5. Present level of contaminants in the Romanian Black Sea sector

    International Nuclear Information System (INIS)

    Bologa, A.S.; Apas, M.; Cociasu, A.; Cuingioglu, E.; Patrascu, V.; Pecheanu, I.; Piescu, V.; Popa, L.

    1999-01-01

    The assessment of environmental quality in the Romanian Black Sea sector is being constantly made by the Romanian Marine Research Institute (RMRI) within the National Integrated Monitoring System. The contamination of the marine environment is expressed by considering four chemical and a biological parameter: nutrients (N-NO 2 , N-NO 3 , N-NH 4 , P-PO 4 , organic P, Si-SiO 4 ), heavy metals (Mn, Fe, Cu, Cd, Pb), artificial radionuclides ( 90 Sr, 137 Cs), total hydrocarbons, parasite and saprophyte fungi in sediments, sea water and/or biota. Present levels of contaminants are discussed as to their historical evolution during the last few years or decades. Inorganic N and P concentrations still exceed three to five times those before eutrophication started to intensify in the early '70s. Practical uses of results by national and regional authorities are discussed. (author)

  6. Characterizing uncertain sea-level rise projections to support investment decisions

    Science.gov (United States)

    Lempert, Robert J.; Wikman-Svahn, Per; Keller, Klaus

    2018-01-01

    Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1) Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2) Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea-level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making such investments

  7. Characterizing uncertain sea-level rise projections to support investment decisions.

    Science.gov (United States)

    Sriver, Ryan L; Lempert, Robert J; Wikman-Svahn, Per; Keller, Klaus

    2018-01-01

    Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1) Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2) Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea-level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making such investments

  8. Characterizing uncertain sea-level rise projections to support investment decisions.

    Directory of Open Access Journals (Sweden)

    Ryan L Sriver

    Full Text Available Many institutions worldwide are considering how to include uncertainty about future changes in sea-levels and storm surges into their investment decisions regarding large capital infrastructures. Here we examine how to characterize deeply uncertain climate change projections to support such decisions using Robust Decision Making analysis. We address questions regarding how to confront the potential for future changes in low probability but large impact flooding events due to changes in sea-levels and storm surges. Such extreme events can affect investments in infrastructure but have proved difficult to consider in such decisions because of the deep uncertainty surrounding them. This study utilizes Robust Decision Making methods to address two questions applied to investment decisions at the Port of Los Angeles: (1 Under what future conditions would a Port of Los Angeles decision to harden its facilities against extreme flood scenarios at the next upgrade pass a cost-benefit test, and (2 Do sea-level rise projections and other information suggest such conditions are sufficiently likely to justify such an investment? We also compare and contrast the Robust Decision Making methods with a full probabilistic analysis. These two analysis frameworks result in similar investment recommendations for different idealized future sea-level projections, but provide different information to decision makers and envision different types of engagement with stakeholders. In particular, the full probabilistic analysis begins by aggregating the best scientific information into a single set of joint probability distributions, while the Robust Decision Making analysis identifies scenarios where a decision to invest in near-term response to extreme sea-level rise passes a cost-benefit test, and then assembles scientific information of differing levels of confidence to help decision makers judge whether or not these scenarios are sufficiently likely to justify making

  9. NOAA Digital Coast Sea Level Rise and Coastal Flooding Impacts Viewer

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Level Rise and Coastal Flooding Impacts Viewer depicts potential sea level rise and its associated impacts on the nation's coastal areas. These coastal areas...

  10. Reconstructing sea level from paleo and projected temperatures 200 to 2100 AD

    DEFF Research Database (Denmark)

    Grinsted, Aslak; Moore, John; Jevrejeva, Svetlana

    2010-01-01

    -proxy reconstructions assuming that the established relationship between temperature and sea level holds from 200 to 2100 ad. Over the last 2,000 years minimum sea level (-19 to -26 cm) occurred around 1730 ad, maximum sea level (12–21 cm) around 1150 AD. Sea level 2090–2099 is projected to be 0.9 to 1.3 m for the A1B...

  11. New evidence for "far-field" Holocene sea level oscillations and links to global climate records

    Science.gov (United States)

    Leonard, N. D.; Welsh, K. J.; Clark, T. R.; Feng, Y.-x.; Pandolfi, J. M.; Zhao, J.-x.

    2018-04-01

    Rising sea level in the coming century is of significant concern, yet predicting relative sea level change in response to eustatic sea level variability is complex. Potential analogues are provided by the recent geological past but, until recently, many sea level reconstructions have been limited to millennial scale interpretations due to age uncertainties and paucity in proxy derived records. Here we present a sea level history for the tectonically stable "far-field" Great Barrier Reef, Australia, derived from 94 high precision uranium-thorium dates of sub-fossil coral microatolls. Our results provide evidence for at least two periods of relative sea level instability during the Holocene. These sea level oscillations are broadly synchronous with Indo-Pacific negative sea surface temperature anomalies, rapid global cooling events and glacial advances. We propose that the pace and magnitude of these oscillations are suggestive of eustatic/thermosteric processes operating in conjunction with regional climatic controls.

  12. Improvement of Global and Regional Mean Sea Level Trends Derived from all Altimetry Missions.

    Science.gov (United States)

    Ablain, Michael; Benveniste, Jérôme; Faugere, Yannice; Larnicol, Gilles; Cazenave, Anny; Johannessen, Johnny A.; Stammer, Detlef; Timms, Gary

    2012-07-01

    The global mean sea level (GMSL) has been calculated on a continual basis since January 1993 using data from satellite altimetry missions. The global mean sea level (MSL) deduced from TOPEX/Poseidon, Jason-1 and Jason-2 is increasing with a global trend of 3.2 mm from 1993 to 2010 applying the post glacial rebound (MSL Aviso website http://www.jason.oceanobs.com/msl). Besides, the regional sea level trends bring out an inhomogeneous repartition of the ocean elevation with local MSL slopes ranging from +/- 8 mm/year. A study published in 2009 [Ablain et al., 2009] has shown that the global MSL trend uncertainty was estimated at +/-0.6 mm/year with a confidence interval of 90%. The main sources of errors at global and regional scales are due to the orbit calculation and the wet troposphere correction. But others sea-level components have also a significant impact on the long-term stability of MSL as for instance the stability of instrumental parameters and the atmospheric corrections. Thanks to recent studies performed in Sea Level Essential Climate Variable Project in the frame of the Climate Change Initiative, an ESA Programme, in addition to activities performed within the SALP/CNES, strong improvements have been provided for the estimation of the global and regional MSL trends. In this paper, we propose to describe them; they concern the orbit calculation thanks to new gravity fields, the atmospheric corrections thanks to ERA-interim reanalyses, the wet troposphere corrections thanks to the stability improvement, and also empirical corrections allowing us to link regional time series together better. These improvements are described at global and regional scale for all the altimetry missions.

  13. ENSO-induced inter-annual sea level variability in the Singapore strait

    Digital Repository Service at National Institute of Oceanography (India)

    Soumya, M.; Vethamony, P.; Tkalich, P.

    Sea level data from four tide gauge stations in the SS (Tanjong Pagar, Sultan Shoal, Sembawang and Raffles Lighthouse) for the period 1970-2012 were extracted to study the ENSO-induced interannual sea level variability Sea level during this period...

  14. Modelling regional sea-level changes in recent past and future

    NARCIS (Netherlands)

    Slangen, A.B.A.

    2012-01-01

    Sea-level change is one of the most important consequences of a warming climate, affecting many densely populated coastal communities. To improve coastal management and the planning of flood defences, information on the future development of sea-level rise is needed. However, sea-level rise is not

  15. Reconstructing Common Era relative sea-level change on the Gulf Coast of Florida

    Science.gov (United States)

    Gerlach, Matthew J.; Engelhart, Simon E.; Kemp, Andrew C.; Moyer, Ryan P.; Smoak, Joseph M.; Bernhardt, Christopher E.; Cahill, Niamh

    2017-01-01

    To address a paucity of Common Era data in the Gulf of Mexico, we reconstructed ~ 1.1 m of relative sea-level (RSL) rise over the past ~ 2000 years at Little Manatee River (Gulf Coast of Florida, USA). We applied a regional-scale foraminiferal transfer function to fossil assemblages preserved in a core of salt-marsh peat and organic silt that was dated using radiocarbon and recognition of pollution, 137Cs and pollen chronohorizons. Our proxy reconstruction was combined with tide-gauge data from four nearby sites spanning 1913–2014 CE. Application of an Errors-in-Variables Integrated Gaussian Process (EIV-IGP) model to the combined proxy and instrumental dataset demonstrates that RSL fell from ~ 350 to 100 BCE, before rising continuously to present. This initial RSL fall was likely the result of local-scale processes (e.g., silting up of a tidal flat or shallow sub-tidal shoal) as salt-marsh development at the site began. Since ~ 0 CE, we consider the reconstruction to be representative of regional-scale RSL trends. We removed a linear rate of 0.3 mm/yr from the RSL record using the EIV-IGP model to estimate climate-driven sea-level trends and to facilitate comparison among sites. This analysis demonstrates that since ~ 0 CE sea level did not deviate significantly from zero until accelerating continuously from ~ 1500 CE to present. Sea level was rising at 1.33 mm/yr in 1900 CE and accelerated until 2014 CE when a rate of 2.02 mm/yr was attained, which is the fastest, century-scale trend in the ~ 2000-year record. Comparison to existing reconstructions from the Gulf coast of Louisiana and the Atlantic coast of northern Florida reveal similar sea-level histories at all three sites. We explored the influence of compaction and fluvial processes on our reconstruction and concluded that compaction was likely insignificant. Fluvial processes were also likely insignificant, but further proxy evidence is needed to fully test this hypothesis. Our results

  16. A marine to freshwater sediment succession from Kowhai Beach wetland, Northland : implications for Holocene sea level

    International Nuclear Information System (INIS)

    Hicks, H.; Nichol, S.L.

    2007-01-01

    An infilled wetland located behind coastal dunes in north-east Northland is used to reconstruct a local history of environmental change spanning early Holocene (c. 7000 yr BP) to modern time. Proxy indicators (sediment texture, diatoms and pollen) provide evidence for a transition from marginal marine- to brackish- to freshwater-conditions in the wetland. Radiocarbon ages constrain the chronology of this succession to 7880-7430 cal. yr BP for the early period of marine conditions, 3570-3210 cal. yr BP for the latter brackish phase and 1060-800 cal. yr BP for the change to freshwater conditions. Within this succession, the diatom record preserves a strong brackish signal at core depths above the limit of the modern tidal range. This is presented as preliminary evidence for a mid-Holocene sea level highstand for northern New Zealand of approximately 1.2 m above present mean sea level. (author). 40 refs., 7 figs., 1 tab

  17. A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

    Science.gov (United States)

    Webb, Edward L.; Friess, Daniel A.; Krauss, Ken W.; Cahoon, Donald R.; Guntenspergen, Glenn R.; Phelps, Jacob

    2013-01-01

    Sea-level rise threatens coastal salt-marshes and mangrove forests around the world, and a key determinant of coastal wetland vulnerability is whether its surface elevation can keep pace with rising sea level. Globally, a large data gap exists because wetland surface and shallow subsurface processes remain unaccounted for by traditional vulnerability assessments using tide gauges. Moreover, those processes vary substantially across wetlands, so modelling platforms require relevant local data. The low-cost, simple, high-precision rod surface-elevation table–marker horizon (RSET-MH) method fills this critical data gap, can be paired with spatial data sets and modelling and is financially and technically accessible to every country with coastal wetlands. Yet, RSET deployment has been limited to a few regions and purposes. A coordinated expansion of monitoring efforts, including development of regional networks that could support data sharing and collaboration, is crucial to adequately inform coastal climate change adaptation policy at several scales.

  18. Sea level characterization of a 1100 g sapphire bolometer

    CERN Document Server

    Pécourt, S; Bobin, C; Coron, N; Jesus, M D; Hadjout, J P; Leblanc, J W; Marcillac, P D

    1999-01-01

    A first characterization of a 1100 g sapphire bolometer, performed at sea level and at a working temperature of 40 mK, is presented. Despite perturbations coming from the high-radioactive background and cosmic rays, calibration spectra could be achieved with an internal alpha source and a sup 5 sup 7 Co gamma-ray source: the experimental threshold is 25 keV, while the FWHM resolution is 17.4 keV for the 122 keV peak. Possible heat release effects are discussed, and a new limit of 9x10 sup - sup 1 sup 4 W/g is obtained for sapphire.

  19. Theoretical models for the muon spectrum at sea level

    International Nuclear Information System (INIS)

    Abdel-Monem, M.S.; Benbrook, J.R.; Osborne, A.R.; Sheldon, W.R.

    1975-01-01

    The absolute vertical cosmic ray muon spectrum is investigated theoretically. Models of high energy interactions (namely, Maeda-Cantrell (MC), Constant Energy (CE), Cocconi-Koester-Perkins (CKP) and Scaling Models) are used to calculate the spectrum of cosmic ray muons at sea level. A comparison is made between the measured spectrum and that predicted from each of the four theoretical models. It is concluded that the recently available measured muon differential intensities agree with the scaling model for energies less than 100 GeV and with the CKP model for energies greater than 200 GeV. The measured differential intensities (Abdel-Monem et al.) agree with scaling. (orig.) [de

  20. Arctic sea-level reconstruction analysis using recent satellite altimetry

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

    2014-01-01

    We present a sea-level reconstruction for the Arctic Ocean using recent satellite altimetry data. The model, forced by historical tide gauge data, is based on empirical orthogonal functions (EOFs) from a calibration period; for this purpose, newly retracked satellite altimetry from ERS-1 and -2...... and Envisat has been used. Despite the limited coverage of these datasets, we have made a reconstruction up to 82 degrees north for the period 1950–2010. We place particular emphasis on determining appropriate preprocessing for the tide gauge data, and on validation of the model, including the ability...

  1. Sea level changes along the Indian coast: Observations and projections

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.; Kumar, K.R.; Fernandes, S.E.; Michael, G.S.; Patwardhan, S.K.

    : CLIMATE CHANGE AND INDIA CURRE NT SCIENCE, VOL. 90, NO. 3, 10 FEBRUARY 2006 *For correspondence. (e - mail: unni@darya.nio.org ) Sea level changes along the Indian coast: Observ a tions and projections A. S. Unnikrishnan 1, *, K. Rupa Kumar... with the occu r rence of tropical cyclones in the Bay of Bengal and associated storm surges in a future climate scenario. Projections for the future are needed for decision making by planners and policy makers. Future pr o jecti ons are made for different...

  2. Benchmarking and testing the “Sea Level Equation”

    DEFF Research Database (Denmark)

    Spada, G.; Barletta, Valentina Roberta; Klemann, V.

    2012-01-01

    through which the methods may be validated. Following the example of the mantle con-vection community and our recent successful Benchmark for Post Glacial Rebound codes (Spada et al., 2011), here we present the results of a benchmark study of independently developed codes de-signed to solve the SLE....... This study has taken place within a collaboration facilitated through the Eu-ropean Cooperation in Science and Technology (COST) Action ES0701. The tests involve predictions of past and current sea level variations, and 3D deformations of the Earth surface. In spite of the significant differences...

  3. Long-range dependence and sea level forecasting

    CERN Document Server

    Ercan, Ali; Abbasov, Rovshan K

    2013-01-01

    This study shows that the Caspian Sea level time series possess long range dependence even after removing linear trends, based on analyses of the Hurst statistic, the sample autocorrelation functions, and the periodogram of the series. Forecasting performance of ARMA, ARIMA, ARFIMA and Trend Line-ARFIMA (TL-ARFIMA) combination models are investigated. The forecast confidence bands and the forecast updating methodology, provided for ARIMA models in the literature, are modified for the ARFIMA models. Sample autocorrelation functions are utilized to estimate the differencing lengths of the ARFIMA

  4. Uprated OMS Engine Status-Sea Level Testing Results

    Science.gov (United States)

    Bertolino, J. D.; Boyd, W. C.

    1990-01-01

    The current Space Shuttle Orbital Maneuvering Engine (OME) is pressure fed, utilizing storable propellants. Performance uprating of this engine, through the use of a gas generator driven turbopump to increase operating pressure, is being pursued by the NASA Johnson Space Center (JSC). Component level design, fabrication, and test activities for this engine system have been on-going since 1984. More recently, a complete engine designated the Integrated Component Test Bed (ICTB), was tested at sea level conditions by Aerojet. A description of the test hardware and results of the sea level test program are presented. These results, which include the test condition operating envelope and projected performance at altitude conditions, confirm the capability of the selected Uprated OME (UOME) configuration to meet or exceed performance and operational requirements. Engine flexibility, demonstrated through testing at two different operational mixture ratios, along with a summary of projected Space Shuttle performance enhancements using the UOME, are discussed. Planned future activities, including ICTB tests at simulated altitude conditions, and recommendations for further engine development, are also discussed.

  5. Real-time reporting and internet-accessible cellular based coastal sea level gauge

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, R.G.P.; Joseph, A.; Agarvadekar, Y.; Mehra, P.; Dabholkar, N.; Parab, A.; Gouveia, A.D.; Tengali, S.

    as on the receiving- side. This adds to the hardware cost as well as software overheads on the receiving- side to check the data integrity for transmission errors. The main benefit of cellular connectivity with GPRS technology is that it utilizes radio resources only...-level data communication systems for the benefit the coastal communities and the local administrators (Joseph and Prabhudesai, 2005). Further, real-time sea-level data would form an important input to storm-surge predictive models and warning systems. Given...

  6. Contribution of vertical land motions to coastal sea level variations: a global synthesis of multisatellite altimetry, tide gauge and GPS measurements

    Science.gov (United States)

    Pfeffer, Julia; Allemand, Pascal

    2016-04-01

    Coastal sea level variations result from a complex mix of climatic, oceanic and geodynamical processes driven by natural and anthropogenic constraints. Combining data from multiple sources is one solution to identify particular processes and progress towards a better understanding of the sea level variations and the assessment of their impacts at coast. Here, we present a global database merging multisatellite altimetry with tide gauges and Global Positioning System (GPS) measurements. Vertical land motions and sea level variations are estimated simultaneously for a network of 886 ground stations with median errors lower than 1 mm/yr. The contribution of vertical land motions to relative sea level variations is explored to better understand the natural hazards associated with sea level rise in coastal areas. Worldwide, vertical land motions dominate 30 % of observed coastal trends. The role of the crust is highly heterogeneous: it can amplify, restrict or counter the effects of climate-induced sea level change. A set of 182 potential vulnerable localities are identified by large coastal subsidence which increases by several times the effects of sea level rise. Though regional behaviours exist, principally caused by GIA (Glacial Isostatic Adjustment), the local variability in vertical land motion prevails. An accurate determination of the vertical motions observed at the coast is fundamental to understand the local processes which contribute to sea level rise, to appraise its impacts on coastal populations and make future predictions.

  7. Sea-level trend in the South China Sea observed from 20 years of along-track satellite altimetric data

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Xu, Qing; Andersen, Ole Baltazar

    2014-01-01

    The sea-level trend in the South China Sea (SCS) is investigated based on 20 years of along-track data from TOPEX and Jason-1/2 satellite altimetry. The average sea-level rise over all the regions in the study area is observed to have a rate of 5.1 ± 0.8 mm year-1 for the period from 1993 to 2012....... The steric sea level contributes 45% to the observed sea-level trend. These results are consistent with previous studies. In addition, the results demonstrate that the maximum sea-level rise rate of 8.4 mm year-1 is occurring off the east coast of Vietnam and eastern part of SCS. During 2010-2011, the La...... Niña event was highly correlated with the dramatic sea-level rise in the SCS; La Niña events were also associated with the maximum rate of sea rise off the east coast of Vietnam, which occurred during 1993 and 2012. We also evaluated the trends in the geophysical (e.g. dynamical atmospheric correction...

  8. Geoethics: IPCC disgraced by violation of observational facts and physical laws in their sea level scenario

    Science.gov (United States)

    Mörner, Nils-Axel

    2014-05-01

    the order of 0.4o C. The improved ARGO measurements starting 2004 give virtually no change, however. The physically possible amount of expansion decreases, of course, with the decreasing water columns towards the coasts, and at the coasts it is zero (±0.0 mm). The redistribution of water masses in response to the Earth's rotation, surface current beat, wind stress, air pressure, etc. is an important factor. It gives local to regional changes, cancelled out on the global scale, however. From a geoethical point of view, it is of course quite blameworthy that IPCC excels in spreading these horror scenarios of a rapid, even accelerating, sea level rise. Besides, modern understanding of the planetary-solar-terrestrial interaction shows that we are now on our way into grand solar minimum with severely colder climate - that is just the opposite to IPCC's talk about an accelerating warming. In science we should debate - but we should not dictate (as IPCC insist upon), and it is here the perspectives of geoethics comes into the picture.

  9. Thermosteric contribution of warming oceans to the global sea level variations

    OpenAIRE

    Bâki Iz H.

    2016-01-01

    Thermosteric contribution of warming oceans to the global sea level variations during the last century was evaluated at globally distributed 27 tide gauge stations with records over 80 years. The assessment was made using a recently proposed lagged model inclusive of a sea level trend, long and decadal periodicities, and lagged sea surface temperature measurements. The new model solutions revealed that almost all the long period periodic sea level changes experienced a...

  10. An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative

    DEFF Research Database (Denmark)

    Legeais, Jean-Francois; Ablain, Michael; Zawadzki, Lionel

    2018-01-01

    , the sea level ECV has been measured from space by different altimetry missions that have provided global and regional observations of sea level variations. As part of the Climate Change Initiative (CCI) program of the European Space Agency (ESA) (established in 2010), the Sea Level project (SL_cci) aimed...... to provide an accurate and homogeneous long-term satellite-based sea level record. At the end of the first phase of the project (2010-2013), an initial version (v1.1) of the sea level ECV was made available to users (Ablain et al., 2015). During the second phase of the project (2014-2017), improved altimeter...

  11. Extremely low genetic diversity across mangrove taxa reflects past sea level changes and hints at poor future responses.

    Science.gov (United States)

    Guo, Zixiao; Li, Xinnian; He, Ziwen; Yang, Yuchen; Wang, Wenqing; Zhong, Cairong; Greenberg, Anthony J; Wu, Chung-I; Duke, Norman C; Shi, Suhua

    2018-04-01

    The projected increases in sea levels are expected to affect coastal ecosystems. Tropical communities, anchored by mangrove trees and having experienced frequent past sea level changes, appear to be vibrant at present. However, any optimism about the resilience of these ecosystems is premature because the impact of past climate events may not be reflected in the current abundance. To assess the impact of historical sea level changes, we conducted an extensive genetic diversity survey on the Indo-Malayan coast, a hotspot with a large global mangrove distribution. A survey of 26 populations in six species reveals extremely low genome-wide nucleotide diversity and hence very small effective population sizes (N e ) in all populations. Whole-genome sequencing of three mangrove species further shows the decline in N e to be strongly associated with the speed of past changes in sea level. We also used a recent series of flooding events in Yalong Bay, southern China, to test the robustness of mangroves to sea level changes in relation to their genetic diversity. The events resulted in the death of half of the mangrove trees in this area. Significantly, less genetically diverse mangrove species suffered much greater destruction. The dieback was accompanied by a drastic reduction in local invertebrate biodiversity. We thus predict that tropical coastal communities will be seriously endangered as the global sea level rises. Well-planned coastal development near mangrove forests will be essential to avert this crisis. © 2017 John Wiley & Sons Ltd.

  12. Aminostratigraphic correlations and paleotemperature implications, Pliocene-Pleistocene high-sea-level deposits, northwestern Alaska

    Science.gov (United States)

    Kaufman, Darrell S.; Brigham-Grette, Julie

    Multiple periods of Late Pliocene and Pleistocene high sea level are recorded by surficial deposits along the coastal plains of northwestern Alaska. Analyses of the extent of amino acid epimerization in fossil molluscan shells from the Nome coastal plain of the northern Bering Sea coast, and from the Alaskan Arctic Coastal Plain of the Chukchi and Beaufort Sea coasts, allow recognition of at least five intervals of higher-than-present relative sea level. Three Late Pliocene transgressions are represented at Nome by the complex and protracted Beringian transgression, and on the Arctic Coastal Plain by the Colvillian, Bigbendian, and Fishcreekian transgressions. These were followed by a lengthy period of non-marine deposition during the Early Pleistocene when sea level did not reach above its present position. A Middle Pleistocene high-sea-level event is represented at Nome by the Anvilian transgression, and on the Arctic Coastal Plain by the Wainwrightian transgression. Anvilian deposits at the type locality are considerably younger than previously thought, perhaps as young as Oxygen-Isotope Stage 11 (˜410,000 BP). Finally, the last interglacial Pelukian transgression is represented discontinuously along the shores of northwestern Alaska. Amino acid epimerization data, together with previous paleomagnetic measurements, radiometric-age determinations, and paleontologic evidence provide geochronological constraints on the sequence of marine deposits. They form the basis of regional correlations and offer a means of evaluating the post-depositional thermal history of the high-sea-level deposits. Provisional correlations between marine units at Nome and the Artic Coastal Plain indicate that the temperature difference that separates the two sites today had existed by about 3.0 Ma. Since that time, the effective diagenetic temperature was lowered by about 3-4°C at both sites, and the mean annual temperature was lowered considerably more. This temperature decrease was

  13. Azimuth selection for sea level measurements using geodetic GPS receivers

    Science.gov (United States)

    Wang, Xiaolei; Zhang, Qin; Zhang, Shuangcheng

    2018-03-01

    Based on analysis of Global Positioning System (GPS) multipath signals recorded by a geodetic GPS receiver, GPS Reflectometry (GPS-R) has demonstrated unique advantages in relation to sea level monitoring. Founded on multipath reflectometry theory, sea level changes can be measured by GPS-R through spectral analysis of recorded signal-to-noise ratio data. However, prior to estimating multipath parameters, it is necessary to define azimuth and elevation angle mask to ensure the reflecting zones are on water. Here, a method is presented to address azimuth selection, a topic currently under active development in the field of GPS-R. Data from three test sites: the Kachemak Bay GPS site PBAY in Alaska (USA), Friday Harbor GPS site SC02 in the San Juan Islands (USA), and Brest Harbor GPS site BRST in Brest (France) are analyzed. These sites are located in different multipath environments, from a rural coastal area to a busy harbor, and they experience different tidal ranges. Estimates by the GPS tide gauges at azimuths selected by the presented method are compared with measurements from physical tide gauges and acceptable correspondence found for all three sites.

  14. What Causes the North Sea Level to Rise Faster over the Last Decade ?

    Science.gov (United States)

    Karpytchev, Mikhail; Letetrel, Camille

    2013-04-01

    We combined tide gauge records (PSMSL) and satellite altimetry data (TOPEX/POSEIDON-JASON 1-2) to reconstruct the mean level of the North Sea and the Norwegian Sea Shelf (NS-NSS) over 1950-2012. The reconstructed NS-NSS mean sea level fluctuations reveal a pronounced interannual variability and a strong sea level acceleration since the mid-1990's. In order to understand the causes of this acceleration, the NS-NSS mean sea level was cross-correlated with the North Atlantic Oscillation and Arctic Oscillation indices. While the interannual variability of the mean sea level correlates well with the NAO/AO indices, the observed acceleration in the NS-NSS mean level is not linked linearly to the NAO/AO fluctuations. On the other hand, the Empirical Orthogonal Functions (EOF) analysis of steric sea level variations in the eastern North Atlantic gives a dominant EOF pattern (55% of variance explained) that varies on a decadal scale very closely to the NS-NSS mean level flcutuations. Also, the amplification in the temporal amplitude of the dominant steric sea level EOF corresponds to the acceleration observed in the NS-NSS mean sea level signal. This suggests that decadal variations in the mean level of the North Sea - the Norwegian Sea Shelf reflect changes in the Subpolar Front currents (Rossby, 1996).

  15. Geophysical Imaging of Sea-level Proxies in Beach-Ridge Deposits

    Science.gov (United States)

    Nielsen, L.; Emerich Souza, P.; Meldgaard, A.; Bendixen, M.; Kroon, A.; Clemmensen, L. B.

    2017-12-01

    We show ground-penetrating radar (GPR) reflection data collected over modern and fossil beach deposits from different localities along coastlines in meso-tidal regimes of Greenland and micro-tidal regimes of Denmark. The acquired reflection GPR sections show several similar characteristics but also some differences. A similar characteristic is the presence of downlapping reflections, where the downlap point is interpreted to mark the transition from upper shoreface to beachface deposits and, thus, be a marker of a level close to or at sea-level at the time of deposition. Differences in grain size of the investigated beach ridge system result in different scattering characteristics of the acquired GPR data. These differences call for tailored, careful processing of the GPR data for optimal imaging of internal beach ridge architecture. We outline elements of the GPR data processing of particular importance for optimal imaging. Moreover, we discuss advantages and challenges related to using GPR-based proxies of sea-level as compared to other methods traditionally used for establishment of curves of past sea-level variation.

  16. Communicating uncertainties in assessments of future sea level rise

    Science.gov (United States)

    Wikman-Svahn, P.

    2013-12-01

    How uncertainty should be managed and communicated in policy-relevant scientific assessments is directly connected to the role of science and the responsibility of scientists. These fundamentally philosophical issues influence how scientific assessments are made and how scientific findings are communicated to policymakers. It is therefore of high importance to discuss implicit assumptions and value judgments that are made in policy-relevant scientific assessments. The present paper examines these issues for the case of scientific assessments of future sea level rise. The magnitude of future sea level rise is very uncertain, mainly due to poor scientific understanding of all physical mechanisms affecting the great ice sheets of Greenland and Antarctica, which together hold enough land-based ice to raise sea levels more than 60 meters if completely melted. There has been much confusion from policymakers on how different assessments of future sea levels should be interpreted. Much of this confusion is probably due to how uncertainties are characterized and communicated in these assessments. The present paper draws on the recent philosophical debate on the so-called "value-free ideal of science" - the view that science should not be based on social and ethical values. Issues related to how uncertainty is handled in scientific assessments are central to this debate. This literature has much focused on how uncertainty in data, parameters or models implies that choices have to be made, which can have social consequences. However, less emphasis has been on how uncertainty is characterized when communicating the findings of a study, which is the focus of the present paper. The paper argues that there is a tension between on the one hand the value-free ideal of science and on the other hand usefulness for practical applications in society. This means that even if the value-free ideal could be upheld in theory, by carefully constructing and hedging statements characterizing

  17. Climate related sea-level variations over the past two millennia.

    Science.gov (United States)

    Kemp, Andrew C; Horton, Benjamin P; Donnelly, Jeffrey P; Mann, Michael E; Vermeer, Martin; Rahmstorf, Stefan

    2011-07-05

    We present new sea-level reconstructions for the past 2100 y based on salt-marsh sedimentary sequences from the US Atlantic coast. The data from North Carolina reveal four phases of persistent sea-level change after correction for glacial isostatic adjustment. Sea level was stable from at least BC 100 until AD 950. Sea level then increased for 400 y at a rate of 0.6 mm/y, followed by a further period of stable, or slightly falling, sea level that persisted until the late 19th century. Since then, sea level has risen at an average rate of 2.1 mm/y, representing the steepest century-scale increase of the past two millennia. This rate was initiated between AD 1865 and 1892. Using an extended semiempirical modeling approach, we show that these sea-level changes are consistent with global temperature for at least the past millennium.

  18. Statistical analysis of global surface air temperature and sea level using cointegration methods

    DEFF Research Database (Denmark)

    Schmith, Torben; Johansen, Søren; Thejll, Peter

    Global sea levels are rising which is widely understood as a consequence of thermal expansion and melting of glaciers and land-based ice caps. Due to physically-based models being unable to simulate observed sea level trends, semi-empirical models have been applied as an alternative for projecting...... of future sea levels. There is in this, however, potential pitfalls due to the trending nature of the time series. We apply a statistical method called cointegration analysis to observed global sea level and surface air temperature, capable of handling such peculiarities. We find a relationship between sea...... level and temperature and find that temperature causally depends on the sea level, which can be understood as a consequence of the large heat capacity of the ocean. We further find that the warming episode in the 1940s is exceptional in the sense that sea level and warming deviates from the expected...

  19. Linear and non-linear sea-level variations in the Adriatic Sea from tide gauge records (1872-2012

    Directory of Open Access Journals (Sweden)

    Gaia Galassi

    2015-03-01

    Full Text Available We have analyzed tide gauge data from the Adriatic Sea in order to assess the secular sea-level trend, its acceleration and the existence of possible cyclic variation. Analyzing the sea-level stack of all Adriatic tide gauges, we have obtained a trend of (1.25±0.04 mm yr-1, in agreement with that observed for the last century in the Mediterranean Sea, and an acceleration that is negligibile compared to the average global values. By means of the Ensemble Empirical Mode Decomposition technique, we have evidenced an energetic oscillation with a period of ∼20 years that we relate with the recurrence of opposite phases in the Atlantic Multi–decadal Oscillation and North Atlantic Oscillation indices. We suggest that anomalously high sea-level values observed at all the Adriatic tide gauges during 2010 and 2011 can be explained by the rising phase of this 20 years cycle.

  20. Comparison of satellite altimetry sea level anomalies and hydrographic observations in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Francisco Mir Calafat

    2012-08-01

    Full Text Available Steric sea level (SSL computed from hydrographic observations in the Mediterranean Sea is compared against altimetric sea level anomalies (SLA at seasonal and inter-annual time scales for the period 1993-2008. SSL (referenced to 300 m is computed using two data sets: in situ profiles and gridded products obtained from interpolated observations. The impact of expendable/mechanical bathythermograph (XBT/MBT biases affecting some of the in situ profiles is investigated by comparing both corrected and uncorrected data. For the period 2003-2008 the mass component is estimated from GRACE observations and subtracted from SLA. The analysis of the spatio-temporal distribution of profiles shows that the number of profiles with data below 300 m is a small percentage of the total and that their spatial coverage of the Mediterranean basin is very limited. This is an important handicap for regions where the contribution of the deep layers to SSL is significant. Overall, SSL and SLA are shown to be consistent in the Mediterranean at seasonal time scales, although the annual amplitude of the SSL from in situ profiles and interpolated data is considerably smaller than that of the SLA. The agreement at inter-annual time scales is less good. At some particular locations SSL computed from individual profiles is more correlated with SLA than the gridded products. At basin and sub-basin scales, however, interpolated and in situ observations provide similar results in terms of their correlation with observed SLA. The XBT/MBT bias corrections have little effect on the SSL at the time scales considered in this study.

  1. The analysis of Last Interglacial (MIS 5e) relative sea-level indicators: Reconstructing sea-level in a warmer world

    NARCIS (Netherlands)

    Rovere, A.; Raymo, M.E.; Vacchi, M.; Lorscheid, T; Stocchi, P.; Gómez-Pujolf, L.; Harris, D.L.; Casella, E.; O'Leary, M.J.; Hearty, P.J.

    2016-01-01

    The Last Interglacial (MIS 5e, 128–116 ka) is among the most studied past periods in Earth's history. The climate at that time was warmer than today, primarily due to different orbital conditions, with smaller ice sheets and higher sea-level. Field evidence for MIS 5e sea-level was reported from

  2. 60-year Nordic and arctic sea level reconstruction based on a reprocessed two decade altimetric sea level record and tide gauges

    OpenAIRE

    Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

    2015-01-01

    Due to the sparsity and often poor quality of data, reconstructing Arctic sea level is highly challenging. We present a reconstruction of Arctic sea level covering 1950 to 2010, using the approaches from Church et al. (2004) and Ray and Douglas (2011). This involves decomposition of an altimetry calibration record into EOFs, and fitting these patterns to a historical tide gauge record.

  3. 60-year Nordic and arctic sea level reconstruction based on a reprocessed two decade altimetric sea level record and tide gauges

    DEFF Research Database (Denmark)

    Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

    Due to the sparsity and often poor quality of data, reconstructing Arctic sea level is highly challenging. We present a reconstruction of Arctic sea level covering 1950 to 2010, using the approaches from Church et al. (2004) and Ray and Douglas (2011). This involves decomposition of an altimetry...

  4. Roles of Sea Level and Climate Change in the Development of Holocene Deltaic Sequences in the Yellow Sea

    Science.gov (United States)

    Liu, J.; Milliman, J. D.

    2002-12-01

    Both post-glacial sea-level and climatic changes are preserved in the the shallow, low gradient, sediment-dominated Yellow Sea. As a result of rapid flooding during melt-water pulse (MWP) 1A, 14.3-14.1 ka BP, sea level reached the southern edge of the North Yellow Sea (NYS), and after MWP-1B (11.6-11.4 ka BP) sea level entered the Bohai Sea. The first major Yellow River-derived deltaic deposit formed in the NYS during decelerated transgression following MWP-1B and increased river discharge in response to re-intensification of the summer monsoon about 11 ka cal BP. A second subaqueous delta formed in the South Yellow Sea about 9-7 ka BP during decelerated transgression after MWP-1C flooding and in response to the southern shift of the Yellow River mouth. The modern subaqueous and subaerial deltas in the west Bahai Gulf and (to a lesser extent) along the Jiangus coast have formed during the modern sea-level highstand. These changing Holocene patterns are most clearly illustrated by a short film clip.

  5. GHRSST Level 4 DMI_OI Global Foundation Sea Surface Temperature Analysis (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the Danish...

  6. GHRSST Level 4 MUR North America Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced as a retrospective dataset at the JPL Physical...

  7. GHRSST Level 4 OSPO Global Nighttime Foundation Sea Surface Temperature Analysis (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Office of...

  8. GHRSST Level 4 AVHRR_AMSR_OI Global Blended Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.25 degree grid at the NOAA...

  9. GHRSST Level 4 G1SST Global Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis by the JPL OurOcean...

  10. GHRSST Level 4 MW_OI Global Foundation Sea Surface Temperature analysis (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.25 degree grid at Remote Sensing...

  11. TOGA Sea Level Center: Data from the Indian Ocean (NODC Accession 9000251)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains a scan of the analog publication 'TOGA Sea Level Center: Data from the Indian Ocean'. Abstract from p. iii of the publication: The TOGA Sea...

  12. GHRSST Level 4 K10_SST Global 1 meter Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Naval...

  13. GHRSST Level 4 ODYSSEA Eastern Central Pacific Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

  14. GHRSST Level 4 ODYSSEA Global Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at Ifremer/CERSAT...

  15. GHRSST Level 4 OSPO Global Foundation Sea Surface Temperature Analysis (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Office of...

  16. GHRSST Level 4 GAMSSA Global Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Australian Bureau...

  17. GHRSST Level 4 RAMSSA Australian Regional Foundation Sea Surface Temperature Analysis (GDS version 1)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the Australian Bureau...

  18. GHRSST Level 4 OSTIA Global Foundation Sea Surface Temperature Analysis (GDS versions 1 and 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A Group for High Resolution Sea Surface Temperature (GHRSST) Level 4 sea surface temperature analysis produced daily on an operational basis at the UK Met Office...

  19. A model of water and sediment balance as determinants of relative sea level rise in contemporary and future deltas

    Science.gov (United States)

    Tessler, Zachary D.; Vörösmarty, Charles J.; Overeem, Irina; Syvitski, James P. M.

    2018-03-01

    Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning and affect the long-term sustainability of these landscapes for human and for natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea level rise across 46 global deltas. We model scenarios of contemporary and future water resource management schemes and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea level rise in delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea level rise result in delta relative sea level rise rates that average 6.8 mm/y. Assessment of impacts of planned and under-construction dams on relative sea level rise rates suggests increases on the order of 1 mm/y in deltas with new upstream construction. Sediment fluxes are estimated to decrease by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Meghna if all currently planned dams are constructed. Reduced sediment retention on deltas caused by increased river channelization and management has a larger impact, increasing relative sea level rise on average by nearly 2 mm/y. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Local and regional strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea level rise.

  20. Carbon choices determine US cities committed to futures below sea level.

    Science.gov (United States)

    Strauss, Benjamin H; Kulp, Scott; Levermann, Anders

    2015-11-03

    Anthropogenic carbon emissions lock in long-term sea-level rise that greatly exceeds projections for this century, posing profound challenges for coastal development and cultural legacies. Analysis based on previously published relationships linking emissions to warming and warming to rise indicates that unabated carbon emissions up to the year 2100 would commit an eventual global sea-level rise of 4.3-9.9 m. Based on detailed topographic and population data, local high tide lines, and regional long-term sea-level commitment for different carbon emissions and ice sheet stability scenarios, we compute the current population living on endangered land at municipal, state, and national levels within the United States. For unabated climate change, we find that land that is home to more than 20 million people is implicated and is widely distributed among different states and coasts. The total area includes 1,185-1,825 municipalities where land that is home to more than half of the current population would be affected, among them at least 21 cities exceeding 100,000 residents. Under aggressive carbon cuts, more than half of these municipalities would avoid this commitment if the West Antarctic Ice Sheet remains stable. Similarly, more than half of the US population-weighted area under threat could be spared. We provide lists of implicated cities and state populations for different emissions scenarios and with and without a certain collapse of the West Antarctic Ice Sheet. Although past anthropogenic emissions already have caused sea-level commitment that will force coastal cities to adapt, future emissions will determine which areas we can continue to occupy or may have to abandon.

  1. Improvement of global and regional mean sea level derived from satellite altimetry multi missions

    Science.gov (United States)

    Ablain, M.; Faugere, Y.; Larnicol, G.; Picot, N.; Cazenave, A.; Benveniste, J.

    2012-04-01

    With the satellite altimetry missions, the global mean sea level (GMSL) has been calculated on a continual basis since January 1993. 'Verification' phases, during which the satellites follow each other in close succession (Topex/Poseidon--Jason-1, then Jason-1--Jason-2), help to link up these different missions by precisely determining any bias between them. Envisat, ERS-1 and ERS-2 are also used, after being adjusted on these reference missions, in order to compute Mean Sea Level at high latitudes (higher than 66°N and S), and also to improve spatial resolution by combining all these missions together. The global mean sea level (MSL) deduced from TOPEX/Poseidon, Jason-1 and Jason-2 provide a global rate of 3.2 mm from 1993 to 2010 applying the post glacial rebound (MSL aviso website http://www.jason.oceanobs.com/msl). Besides, the regional sea level trends bring out an inhomogeneous repartition of the ocean elevation with local MSL slopes ranging from + 8 mm/yr to - 8 mm/year. A study published in 2009 [Ablain et al., 2009] has shown that the global MSL trend unceratainty was estimated at +/-0.6 mm/year with a confidence interval of 90%. The main sources of errors at global and regional scales are due to the orbit calculation and the wet troposphere correction. But others sea-level components have also a significant impact on the long-term stability of MSL as for instance the stability of instrumental parameters and the atmospheric corrections. Thanks to recent studies performed in the frame of the SALP project (supported by CNES) and Sea-level Climate Change Initiative project (supported by ESA), strong improvements have been provided for the estimation of the global and regional MSL trends. In this paper, we propose to describe them; they concern the orbit calculation thanks to new gravity fields, the atmospheric corrections thanks to ERA-interim reanalyses, the wet troposphere corrections thanks to the stability improvement, and also empirical corrections

  2. Holocene sea-level changes along the Strait of Magellan and Beagle Channel, southernmost South America

    Science.gov (United States)

    Porter, Stephen C.; Stuiver, Minze; Heusser, Calvin J.

    1984-07-01

    Radiocarbon-dated marine sediments from five coastal sites along the Strait of Magellan and Beagle Channel in southernmost Chile permit construction of a curve of relative sea-level fluctuations during the Holocene. Morphologic and stratigraphic data point to coastal submergence during the early Holocene as the sea rose to a maximum level at least 3.5 m higher than present about 5000 yr ago. Progressive emergence then followed during the late Holocene. Data from widely separated localities define a smooth curve, the form of which is explainable in terms of isostatic and hydroisostatic deformation of the crust resulting from changing ice and water loads. Apparently anomalous data from one site located more than 100 km behind the outer limit of the last glaciation may reflect isostatic response to deglaciation. The sea-level curve resembles one derived by Clark and Bloom (1979, In "Proceedings of the 1978 International Symposium on Coastal Evolution in the Quaternary, Sao Paulo, Brasil," pp. 41-60. Sao Paulo) using a spherical Earth model, both in amplitude and in the timing of the maximum submergence.

  3. Constraining the Antarctic contribution to interglacial sea-level rise

    Science.gov (United States)

    Naish, T.; Mckay, R. M.; Barrett, P. J.; Levy, R. H.; Golledge, N. R.; Deconto, R. M.; Horgan, H. J.; Dunbar, G. B.

    2015-12-01

    Observations, models and paleoclimate reconstructions suggest that Antarctica's marine-based ice sheets behave in an unstable manner with episodes of rapid retreat in response to warming climate. Understanding the processes involved in this "marine ice sheet instability" is key for improving estimates of Antarctic ice sheet contribution to future sea-level rise. Another motivating factor is that far-field sea-level reconstructions and ice sheet models imply global mean sea level (GMSL) was up to 20m and 10m higher, respectively, compared with present day, during the interglacials of the warm Pliocene (~4-3Ma) and Late Pleistocene (at ~400ka and 125ka). This was when atmospheric CO2 was between 280 and 400ppm and global average surface temperatures were 1- 3°C warmer, suggesting polar ice sheets are highly sensitive to relatively modest increases in climate forcing. Such magnitudes of GMSL rise not only require near complete melt of the Greenland Ice Sheet and the West Antarctic Ice Sheet, but a substantial retreat of marine-based sectors of East Antarctic Ice Sheet. Recent geological drilling initiatives on the continental margin of Antarctica from both ship- (e.g. IODP; International Ocean Discovery Program) and ice-based (e.g. ANDRILL/Antarctic Geological Drilling) platforms have provided evidence supporting retreat of marine-based ice. However, without direct access through the ice sheet to archives preserved within sub-glacial sedimentary basins, the volume and extent of ice sheet retreat during past interglacials cannot be directly constrained. Sediment cores have been successfully recovered from beneath ice shelves by the ANDRILL Program and ice streams by the WISSARD (Whillans Ice Stream Sub-glacial Access Research Drilling) Project. Together with the potential of the new RAID (Rapid Access Ice Drill) initiative, these demonstrate the technological feasibility of accessing the subglacial bed and deeper sedimentary archives. In this talk I will outline the

  4. Sea level rise under the Shared Socioeconomic Pathways (SSPs)

    Science.gov (United States)

    Schleussner, C. F.; Nauels, A.; Rogelj, J.; Mengel, M.; Meinshausen, M.

    2017-12-01

    In order to assess future sea level rise and its impacts, we need to study climate change pathways combined with different scenarios of socioeconomic development. Here, we present Sea Level Rise (SLR) projections for the Shared Socioeconomic Pathway (SSP) storylines and different year-2100 radiative Forcing Targets (FTs). Future SLR is estimated with a comprehensive SLR emulator that accounts for latest research on additional Antarctic rapid discharge dynamics from hydrofracturing and ice cliff instability. Across all baseline scenario realizations (no dedicated climate mitigation), we find 2100 median SLR relative to 1986-2005 of 102 cm (likely range: 77 to 135 cm) for SSP1, 118 cm (90 to 151 cm) for SSP2, 118 cm (91 to 149 cm) for SSP3, 107 cm (81 to 137 cm) for SSP4, and 144 cm (112 to 184 cm) for SSP5. The 2100 sea level responses for combined SSP-FT scenarios is dominated by the mitigation targets and yield median estimates of 68 cm (56 to 87 cm) for FT 2.6 Wm-2, 76 cm (61 to 107 cm) for FT 3.4 Wm-2, 90 cm (68 to 120 cm) for FT 4.5 Wm-2, and 105 cm (79 to 136 cm) for FT 6.0 Wm-2. Average 2081-2100 annual rates of SLR are 6 mm/yr and 19 mm/yr for the FT 2.6 Wm-2 and the baseline scenarios, respectively. Our model setup allows linking scenario-specific emission and socioeconomic indicators to projected SLR. For limiting median 2100 SSP SLR projections to below 80 cm, we find that 2050 cumulative CO2 emissions since pre-industrial should not exceed around 860 GtC, with the global coal phase-out nearly completed. For SSP mitigation scenarios, the median 2050 carbon price of 90 US$2005 tCO2-1 would correspond to a median 2100 SLR of around 80 cm. Our results confirm that rapid and early emission reductions are essential for limiting 2100 SLR.

  5. Development of new geoinformation methods for modelling and prediction of sea level change over different timescales - overview of the project

    Science.gov (United States)

    Niedzielski, T.; Włosińska, M.; Miziński, B.; Hewelt, M.; Migoń, P.; Kosek, W.; Priede, I. G.

    2012-04-01

    The poster aims to provide a broad scientific audience with a general overview of a project on sea level change modelling and prediction that has just commenced at the University of Wrocław, Poland. The initiative that the project fits, called the Homing Plus programme, is organised by the Foundation for Polish Science and financially supported by the European Union through the European Regional Development Fund and the Innovative Economy Programme. There are two key research objectives of the project that complement each other. First, emphasis is put on modern satellite altimetric gridded time series from the Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO) repository. Daily sea level anomaly maps, access to which in near-real time is courtesy of AVISO, are being steadily downloaded every day to our local server in Wroclaw, Poland. These data will be processed within a general framework of modelling and prediction of sea level change in short, medium and long term. Secondly, sea level change over geological time is scrutinised in order to cover very long time scales that go far beyond a history of altimetric and tide-gauge measurements. The aforementioned approaches comprise a few tasks that aim to solve the following detailed problems. Within the first one, our objective is to seek spatio-temporal dependencies in the gridded sea level anomaly time series. Subsequently, predictions that make use of such cross-correlations shall be derived, and near-real time service for automatic update with validation will be implemented. Concurrently, (i.e. apart from spatio-temporal dependencies and their use in the process of forecasting variable sea level topography), threshold models shall be utilised for predicting the El Niño/Southern Oscillation (ENSO) signal that is normally present in sea level anomaly time series of the equatorial Pacific. Within the second approach, however, the entirely different methods are proposed. Links between

  6. Real-time reporting and internet-accessible coastal sea-level gauge

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, R.G.P.; Joseph, A.; Agarvadekar, Y.; Mehra, P.; Dabholkar, N.; Parab, A.; Gouveia, A.D.; Tengali, S.

    on the remote transmitting device as well as on the receiving end. This adds to the hardware cost as well as software overheads on the receiving end to check the data integrity for transmission errors [5]. The main benefit of cellular connectivity with GPRS... for the benefit of the coastal communities and the local administrators [1]. Further, real-time sea-level data would form an important input to predictive models and warning systems. 2. Description A major limitation of existing float-driven and guided...

  7. Optical dating results of beachrock, eolic dunes and sediments applied to sea-level changes study

    International Nuclear Information System (INIS)

    Tatumi, S.H.; Kowata, E.A.; Gozzi, G.; Kassab, L.R.P.; Suguio, K.; Barreto, A.M.F.; Bezerra, F.H.R.

    2003-01-01

    Quartz and feldspar crystals were selected from the samples as eolic dunes, beach-rock and marine terraces, all collected in the coast area of Paraiba State, located in northeastern Brazil, in order to obtain ages of deposition of the sediments. It is a systematic study in the area. The results of the ages will be used in local sea-level changes study and a correlation between highstands of marine oxygen-isotopes stages will be made. Optically stimulated luminescence and thermoluminescence have been measured and the regeneration method with multiple aliquot protocol was applied to obtain the paleodose values. Preliminaries ages spanning 3.2-229 kyr were evaluated

  8. Optical dating results of beachrock, eolic dunes and sediments applied to sea-level changes study

    Energy Technology Data Exchange (ETDEWEB)

    Tatumi, S.H. E-mail: tatumi@fatecsp.br; Kowata, E.A.; Gozzi, G.; Kassab, L.R.P.; Suguio, K.; Barreto, A.M.F.; Bezerra, F.H.R

    2003-05-01

    Quartz and feldspar crystals were selected from the samples as eolic dunes, beach-rock and marine terraces, all collected in the coast area of Paraiba State, located in northeastern Brazil, in order to obtain ages of deposition of the sediments. It is a systematic study in the area. The results of the ages will be used in local sea-level changes study and a correlation between highstands of marine oxygen-isotopes stages will be made. Optically stimulated luminescence and thermoluminescence have been measured and the regeneration method with multiple aliquot protocol was applied to obtain the paleodose values. Preliminaries ages spanning 3.2-229 kyr were evaluated.

  9. Fluvial Responses to Holocene sea Level Variations Along the Macdonald River, New South Wales, Australia

    Science.gov (United States)

    Rustomji, P.; Chappell, J.; Olley, J.

    2003-12-01

    The Macdonald River drains the rugged eastern flanks of Australia's Great Dividing Range. It has a catchment area of 2000km2, restricted alluvial lowlands confined by bedrock interfluves and flows into the Hawkesbury River, a larger estuarine valley. The Macdonald valley is presently tidal for 14km from the Hawkesbury. At about 8000 year before present (BP), rising sea level invaded the Macdonald Valley for at least 35km upstream of the Hawkesbury River. Rapid aggradation occurred between 8000 and 6000 years BP and a sand bed river was established in the Macdonald Valley, its mouth prograding rapidly towards the Hawkesbury. Little is known about the character of the sand bed river during the +2 meter sea level highstand occurring between 5000 and 4000 BP. However, from 3000 to 1500 BP when sea level was consistently at +1 to +1.5m, major floodplain and levee-like structures, now virtually inactive, were established. The bed is inferred to have been elevated above its present day level and consequently intersected mean sea level (MSL) downstream of its present location. This is consistent with reported sea levels at +1 to +2m above present levels for the New South Wales coast at this time. From 1500 years BP, local sea level fell rapidly to its present level. Aggradation of the levee crests ceased and sedimentation along the valley became restricted to aggradation of an inset floodplain, within the pre-1500 BP deposits. The channel contracted and the sandy river bed incised. An equivalent and synchronous change in sedimentation style is observed along the Tuross River 400km south of the Macdonald, lending support to sea level variations being the factor driving this change. By 1850 AD, the bed dipped below MSL about 10km upstream of its inferred position prior to 1500 years BP. A series of large floods between 1949 and 1955 eroded significant volumes of sandy sediment from the Holocene deposits. The channel bed widened from between 25 and 50m width to ˜100m along

  10. Revisiting global mean sea level budget closure : Preliminary results from an integrative study within ESA's Climate Change Initiative -Sea level Budget Closure-Climate Change Initiative

    Science.gov (United States)

    Palanisamy, H.; Cazenave, A. A.

    2017-12-01

    The global mean sea level budget is revisited over two time periods: the entire altimetry era, 1993-2015 and the Argo/GRACE era, 2003-2015 using the version '0' of sea level components estimated by the SLBC-CCI teams. The SLBC-CCI is an European Space Agency's project on sea level budget closure using CCI products. Over the entire altimetry era, the sea level budget was performed as the sum of steric and mass components that include contributions from total land water storage, glaciers, ice sheets (Greenland and Antarctica) and total water vapor content. Over the Argo/GRACE era, it was performed as the sum of steric and GRACE based ocean mass. Preliminary budget analysis performed over the altimetry era (1993-2015) results in a trend value of 2.83 mm/yr. On comparison with the observed altimetry-based global mean sea level trend over the same period (3.03 ± 0.5 mm/yr), we obtain a residual of 0.2 mm/yr. In spite of a residual of 0.2 mm/yr, the sea level budget result obtained over the altimetry era is very promising as this has been performed using the version '0' of the sea level components. Furthermore, uncertainties are not yet included in this study as uncertainty estimation for each sea level component is currently underway. Over the Argo/GRACE era (2003-2015), the trend estimated from the sum of steric and GRACE ocean mass amounts to 2.63 mm/yr while that observed by satellite altimetry is 3.37 mm/yr, thereby leaving a residual of 0.7 mm/yr. Here an ensemble GRACE ocean mass data (mean of various available GRACE ocean mass data) was used for the estimation. Using individual GRACE data results in a residual range of 0.5 mm/yr -1.1 mm/yr. Investigations are under way to determine the cause of the vast difference between the observed sea level and the sea level obtained from steric and GRACE ocean mass. One main suspect is the impact of GRACE data gaps on sea level budget analysis due to lack of GRACE data over several months since 2011. The current action plan

  11. Possible impact of rising sea levels on vector-borne infectious diseases

    Directory of Open Access Journals (Sweden)

    Surendran Sinnathamby N

    2011-01-01

    Full Text Available Abstract Background Vector-borne infectious diseases are a significant cause of human and animal mortality and morbidity. Modeling studies predict that changes in climate that accompany global warming will alter the transmission risk of many vector-borne infectious diseases in different parts of the world. Global warming will also raise sea levels, which will lead to an increase in saline and brackish water bodies in coastal areas. The potential impact of rising sea levels, as opposed to climate change, on the prevalence of vector-borne infectious diseases has hitherto been unrecognised. Presentation of the hypothesis Mosquito species possessing salinity-tolerant larvae and pupae, and capable of transmitting arboviruses and parasites are found in many parts of the world. An expansion of brackish and saline water bodies in coastal areas, associated with rising sea levels, can increase densities of salinity-tolerant vector mosquitoes and lead to the adaptation of freshwater vectors to breed in brackish and saline waters. The breeding of non-mosquito vectors may also be influenced by salinity changes in coastal habitats. Higher vector densities can increase transmission of vector-borne infectious diseases in coastal localities, which can then spread to other areas. Testing the hypothesis The demonstration of increases in vector populations and disease prevalence that is related to an expansion of brackish/saline water bodies in coastal areas will provide the necessary supportive evidence. However the implementation of specific vector and disease control measures to counter the threat will confound the expected findings. Implications of the hypothesis Rising sea levels can act synergistically with climate change and then interact in a complex manner with other environmental and socio-economic factors to generate a greater potential for the transmission of vector-borne infectious diseases. The resulting health impacts are likely to be particularly

  12. 21st Century Sea-Level Rise in Line with the Paris Accord

    Science.gov (United States)

    Jackson, Luke P.; Grinsted, Aslak; Jevrejeva, Svetlana

    2018-02-01

    As global average sea-level rises in the early part of this century there is great interest in how much global and local sea level will change in the forthcoming decades. The Paris Climate Agreement's proposed temperature thresholds of 1.5°C and 2°C have directed the research community to ask what differences occur in the climate system for these two states. We have developed a novel approach to combine climate model outputs that follow specific temperature pathways to make probabilistic projections of sea-level in a 1.5°C and 2°C world. We find median global sea-level (GSL) projections for 1.5°C and 2°C temperature pathways of 44 and 50 cm, respectively. The 90% uncertainty ranges (5%-95%) are both around 48 cm by 2100. In addition, we take an alternative approach to estimate the contribution from ice sheets by using a semi-empirical GSL model. Here we find median projections of 58 and 68 cm for 1.5°C and 2°C temperature pathways. The 90% uncertainty ranges are 67 and 82 cm respectively. Regional projections show similar patterns for both temperature pathways, though differences vary between the median projections (2-10 cm) and 95th percentile (5-20 cm) for the bulk of oceans using process-based approach and 10-15 cm (median) and 15-25 cm (95th percentile) using the semi-empirical approach.

  13. Postglacial relative sea-level history of the Prince Rupert area, British Columbia, Canada

    Science.gov (United States)

    Letham, Bryn; Martindale, Andrew; Macdonald, Rebecca; Guiry, Eric; Jones, Jacob; Ames, Kenneth M.

    2016-12-01

    This paper presents a history of relative sea level (RSL) change for the last 15,000 years in the Prince Rupert region on the northern coast of British Columbia, Canada. One hundred twenty-three radiocarbon ages of organic material from isolation basin cores, sediment sequence exposures, and archaeological sites having a recognized relation to past sea levels constrain postglacial RSL. The large number of new measurements relating to past sea-level provides a well constrained RSL curve that differs in significant ways from previously published results. After deglaciation following the Last Glacial Maximum, the region experienced an isostatically-induced rapid RSL drop from as much 50 m asl to as low as -6.3 m asl in as little as a few centuries between 14,500 BP and 13,500 BP. After a lowstand below current sea level for about 2000 years during the terminal Pleistocene, RSL rose again to a highstand at least 6 m asl after the end of the Younger Dryas. RSL slowly dropped through the Holocene to close to its current position by 2000-1500 BP, with some potential fluctuations between 3500 and 1500 BP. This study highlights variation in RSL histories across relatively short distances, which must be accounted for by local RSL reconstructions such as this one. This RSL curve aided in the identification of an 8000-9000 year old archaeological site on a 10-12 m asl terrace, which is currently the earliest dated archaeological site in the area, and it provides guidance for searching for even older archaeological remains. We highlight the utility and potential of this refined RSL history for developing surveys for other archaeological sites associated with paleoshorelines.

  14. Ice sheet-ocean interactions and sea level change

    Science.gov (United States)

    Heimbach, Patrick

    2014-03-01

    Mass loss from the Greenland and Antarctic ice sheets has increased rapidly since the mid-1990s. Their combined loss now accounts for about one-third of global sea level rise. In Greenland, a growing body of evidence points to the marine margins of these glaciers as the region from which this dynamic response originated. Similarly, ice streams in West Antarctica that feed vast floating ice shelves have exhibited large decadal changes. We review observational evidence and present physical mechanisms that might explain the observed changes, in particular in the context of ice sheet-ocean interactions. Processes involve cover 7 orders of magnitudes of scales, ranging from mm boundary-layer processes to basin-scale coupled atmosphere-ocean variability. We discuss observational needs to fill the gap in our mechanistic understanding.

  15. Metal tissue levels in Steller sea lion (Eumetopias jubatus) pups

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, Amie L.; Wise, Sandra S. [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth Street, Portland, ME 04104 (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth Street, Portland, ME 04104 (United States); Goertz, Caroline E.C. [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth Street, Portland, ME 04104 (United States); Alaska SeaLife Center, 301 Railway Avenue, Seward, AK 99664 (United States); Dunn, J. Lawrence [Department of Research and Veterinary Care, Mystic Aquarium, 55 Coogan Boulevard, Mystic, CT 06355 (United States); Gulland, Frances M.D. [Marine Mammal Center, 1065 Fort Cronkhite, Sausalito, CA 94965 (United States); Gelatt, Tom [National Marine Fisheries Service, Alaska Fisheries Science Center, National Marine Mammal Lab, 7600 Sand Point Way NE, Seattle, WA 98115 (United States); Beckmen, Kimberlee B. [Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701 (United States); Burek, Kathy [Veterinary Pathology Services, 23834 The Clearing Drive, Eagle River, AK 99577 (United States); Atkinson, Shannon; Bozza, Mary [Alaska SeaLife Center, 301 Railway Avenue, Seward, AK 99664 (United States); Taylor, Robert [Department of Veterinary Integrative Biosciences, Texas A and M University, Highway 60, College Station, TX 77843 (United States); Zheng Tongzhang; Zhang Yawei [School of Epidemiology and Public Health, Yale University, 60 College Street, New Haven, CT 06520 (United States); Aboueissa, AbouEl-Makarim [Department of Mathematics and Statistics, University of Southern Maine, 96 Falmouth Street, Portland, ME 04104 (United States)] (and others)

    2008-08-15

    The endangered Western population of the Steller sea lion declined for three decades for uncertain reasons. We present baseline data of metal concentrations in pups as a first step towards investigating the potential threat of developmental exposures to contaminants. Seven metals were investigated: arsenic, cadmium, silver, aluminum, mercury, lead and vanadium. Vanadium was detected in only a single blubber sample. Mercury appears to be the most toxicologically significant metal with concentrations in the liver well above the current action level for mercury in fish. The concentrations of aluminum, arsenic, silver, cadmium and lead were present in one-fourth to two-thirds of all samples and were at either comparable or below concentrations previously reported. Neither gender nor region had a significant effect on metal burdens. Future work should consider metal concentrations in juveniles and adults and toxicological studies need to be performed to begin to assess the toxicity of these metals.

  16. Metal tissue levels in Steller sea lion (Eumetopias jubatus) pups.

    Science.gov (United States)

    Holmes, Amie L; Wise, Sandra S; Goertz, Caroline E C; Dunn, J Lawrence; Gulland, Frances M D; Gelatt, Tom; Beckmen, Kimberlee B; Burek, Kathy; Atkinson, Shannon; Bozza, Mary; Taylor, Robert; Zheng, Tongzhang; Zhang, Yawei; Aboueissa, Abouel-Makarim; Wise, John Pierce

    2008-08-01

    The endangered Western population of the Steller sea lion declined for three decades for uncertain reasons. We present baseline data of metal concentrations in pups as a first step towards investigating the potential threat of developmental exposures to contaminants. Seven metals were investigated: arsenic, cadmium, silver, aluminum, mercury, lead and vanadium. Vanadium was detected in only a single blubber sample. Mercury appears to be the most toxicologically significant metal with concentrations in the liver well above the current action level for mercury in fish. The concentrations of aluminum, arsenic, silver, cadmium and lead were present in one-fourth to two-thirds of all samples and were at either comparable or below concentrations previously reported. Neither gender nor region had a significant effect on metal burdens. Future work should consider metal concentrations in juveniles and adults and toxicological studies need to be performed to begin to assess the toxicity of these metals.

  17. Metal tissue levels in Steller sea lion (Eumetopias jubatus) pups

    International Nuclear Information System (INIS)

    Holmes, Amie L.; Wise, Sandra S.; Goertz, Caroline E.C.; Dunn, J. Lawrence; Gulland, Frances M.D.; Gelatt, Tom; Beckmen, Kimberlee B.; Burek, Kathy; Atkinson, Shannon; Bozza, Mary; Taylor, Robert; Zheng Tongzhang; Zhang Yawei; Aboueissa, AbouEl-Makarim

    2008-01-01

    The endangered Western population of the Steller sea lion declined for three decades for uncertain reasons. We present baseline data of metal concentrations in pups as a first step towards investigating the potential threat of developmental exposures to contaminants. Seven metals were investigated: arsenic, cadmium, silver, aluminum, mercury, lead and vanadium. Vanadium was detected in only a single blubber sample. Mercury appears to be the most toxicologically significant metal with concentrations in the liver well above the current action level for mercury in fish. The concentrations of aluminum, arsenic, silver, cadmium and lead were present in one-fourth to two-thirds of all samples and were at either comparable or below concentrations previously reported. Neither gender nor region had a significant effect on metal burdens. Future work should consider metal concentrations in juveniles and adults and toxicological studies need to be performed to begin to assess the toxicity of these metals

  18. Mental health issues from rising sea level in a remote coastal region of the Solomon Islands: current and future.

    Science.gov (United States)

    Asugeni, James; MacLaren, David; Massey, Peter D; Speare, Rick

    2015-12-01

    There is little published research about mental health and climate change in the Pacific, including Solomon Islands. Solomon Islands has one of the highest rates of sea-level rise globally. The aim of this research was to document mental health issues related to sea-level rise for people in East Malaita, Solomon Islands. A cross-sectional study was carried out in six low-lying villages in East Malaita, Solomon Islands. The researcher travelled to villages by dugout canoe. In addition to quantitative, closed-ended questions, open-ended questions with villagers explored individual and community responses to rising sea level. Of 60 people asked, 57 completed the questionnaire. Of these, 90% reported having seen a change in the weather patterns. Nearly all participants reported that sea-level rise is affecting them and their family and is causing fear and worry on a personal and community level. Four themes emerged from the qualitative analysis: experience of physical impacts of climate change; worry about the future; adaptation to climate change; government response needed. Given predictions of ongoing sea-level rise in the Pacific it is essential that more research is conducted to further understand the human impact of climate change for small island states which will inform local, provincial and national-level mental health responses. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  19. Spectral analysis of highly aliased sea-level signals

    Science.gov (United States)

    Ray, Richard D.

    1998-10-01

    Observing high-wavenumber ocean phenomena with a satellite altimeter generally calls for "along-track" analyses of the data: measurements along a repeating satellite ground track are analyzed in a point-by-point fashion, as opposed to spatially averaging data over multiple tracks. The sea-level aliasing problems encountered in such analyses can be especially challenging. For TOPEX/POSEIDON, all signals with frequency greater than 18 cycles per year (cpy), including both tidal and subdiurnal signals, are folded into the 0-18 cpy band. Because the tidal bands are wider than 18 cpy, residual tidal cusp energy, plus any subdiurnal energy, is capable of corrupting any low-frequency signal of interest. The practical consequences of this are explored here by using real sea-level measurements from conventional tide gauges, for which the true oceanographic spectrum is known and to which a simulated "satellite-measured" spectrum, based on coarsely subsampled data, may be compared. At many locations the spectrum is sufficently red that interannual frequencies remain unaffected. Intra-annual frequencies, however, must be interpreted with greater caution, and even interannual frequencies can be corrupted if the spectrum is flat. The results also suggest that whenever tides must be estimated directly from the altimetry, response methods of analysis are preferable to harmonic methods, even in nonlinear regimes; this will remain so for the foreseeable future. We concentrate on three example tide gauges: two coastal stations on the Malay Peninsula where the closely aliased K1 and Ssa tides are strong and at Canton Island where trapped equatorial waves are aliased.

  20. Adaptation to the Impacts of Sea Level Rise in Egypt

    International Nuclear Information System (INIS)

    El-Raey, M.; Dewidar, K.R.; El-Hattab, M.

    1999-01-01

    Assessment of the vulnerability and expected socioeconomic losses over the Nile delta coast due to the impact of sea level rise is carried out in details. Impacts of sea level rise over the Governorates of Alexandria and Port Said in particular, are evaluated quantitatively. Analysis of the results at Alexandria Governorate indicate that, if no action is taken, an area of about 30% of the city will be lost due to inundation. Almost 2 million people will have to abandon their homeland; 195,000 jobs will be lost and an economic loss of over $3.5 Billion is expected over the next century. At Port Said Governorate results indicate that beach areas are most severely affected (hence tourism), followed by urban areas. The agriculture sector is the least affected sector. It is estimated that the economic loss is over $ 2.0 Billion for 0.50 m SLR and may exceed $ 4.4 Billion for 1.25 m SLR. Options and costs of adaptation are analyzed and presented. Multi-criteria and decision matrix approaches, based on questionnaire surveys are carried out to identify priorities for the two cases. Analysis of these techniques of two options; the current policy (hard protection measures on some vulnerable areas) and no action (stopping these activities) have the lowest scores. Beach nourishment and integrated coastal zone management (ICZM) have the highest scores, however ICZM has high cost measures. The most cost effective option is the land-use change, however with relatively very high cost measure. It is recommended that an ICZM approach be adopted since it provides a reasonable trade off between costs and cost effectiveness. 14 refs

  1. Climate Sensitivity, Sea Level, and Atmospheric Carbon Dioxide

    Science.gov (United States)

    Hansen, James; Sato, Makiko; Russell, Gary; Kharecha, Pushker

    2013-01-01

    Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3+/-1deg C for a 4 W/sq m CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3-4deg C for a 4 W/sq m CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.

  2. Multivariate Regression Approach To Integrate Multiple Satellite And Tide Gauge Data For Real Time Sea Level Prediction

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Andersen, Ole Baltazar; Knudsen, Per

    2010-01-01

    The Sea Level Thematic Assembly Center in the EUFP7 MyOcean project aims at build a sea level service for multiple satellite sea level observations at a European level for GMES marine applications. It aims to improve the sea level related products to guarantee the sustainability and the quality...

  3. Regional Sea Level Scenarios for Coastal Risk Management: Managing the Uncertainty of Future Sea Level Change and Extreme Water Levels for Department of Defense Coastal Sites Worldwide

    Science.gov (United States)

    2016-04-01

    authors and do not necessarily reflect the view of the authors’ Agencies. MANAGING THE UNCERTAINTY OF FUTURE SEA LEVEL CHANGE AND EXTREME WATER LEVELS FOR...COASTAL RISK MANAGEMENT 2-20 contingent probabilities given their dependence on non-probabilistic emissions futures, have extended the ranges of...flood risk provides confidence in the associated projection as a true minimum value for risk management purposes. The contemporary rate observed by

  4. NCEI ocean heat content, temperature anomalies, salinity anomalies, thermosteric sea level anomalies, halosteric sea level anomalies, and total steric sea level anomalies from 1955 to present calculated from in situ oceanographic subsurface profile data (NCEI Accession 0164586)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains ocean heat content change, oceanic temperature and salinity changes, and steric sea level change (change in volume without change in mass),...

  5. Prevention of oil spill pollution in sea water using locally available materials

    International Nuclear Information System (INIS)

    Anisuddin, S.; Al-Hashar, Naseer A.; Tahseen, S.

    2005-01-01

    Oil spill pollution, a severe environmental problem, which persists in marine environment or in inland water across the world, has grown to an alarming magnitude with increased levels of oil production and transport. The causes oil pollution are categorized as either accidental or operational, wherever oil is produced, transported, stored and used on the surface of sea or land. Hence, it is almost impossible for marine life to be freed from the adverse affects of oil spill, through the discharge of oil is controlled by an international convention. Prime concern for the health of marine life has created an instinct for undertaking this study by authors. Objectives of the present work include testing of four different local materials in separating oil from having different oil concentrations, and their efficiency of removal. The work also focuses on effect of time of contact and dosage of materials used for oil removal. Corchorus depressus locally available has proved to be more effective when compared to other materials utilized in addressing oil-spill related problems. At the same time its byproducts do not give rise to unwanted hazards to marine life. (author)

  6. Statistical analysis of global surface temperature and sea level using cointegration methods

    DEFF Research Database (Denmark)

    Schmidt, Torben; Johansen, Søren; Thejll, Peter

    2012-01-01

    Global sea levels are rising which is widely understood as a consequence of thermal expansion and melting of glaciers and land-based ice caps. Due to the lack of representation of ice-sheet dynamics in present-day physically-based climate models being unable to simulate observed sea level trends......, semi-empirical models have been applied as an alternative for projecting of future sea levels. There is in this, however, potential pitfalls due to the trending nature of the time series. We apply a statistical method called cointegration analysis to observed global sea level and land-ocean surface air...... temperature, capable of handling such peculiarities. We find a relationship between sea level and temperature and find that temperature causally depends on the sea level, which can be understood as a consequence of the large heat capacity of the ocean. We further find that the warming episode in the 1940s...

  7. Sedimentary noise and sea levels linked to land-ocean water exchange and obliquity forcing.

    Science.gov (United States)

    Li, Mingsong; Hinnov, Linda A; Huang, Chunju; Ogg, James G

    2018-03-08

    In ancient hothouses lacking ice sheets, the origins of large, million-year (myr)-scale sea-level oscillations remain a mystery, challenging current models of sea-level change. To address this mystery, we develop a sedimentary noise model for sea-level changes that simultaneously estimates geologic time and sea level from astronomically forced marginal marine stratigraphy. The noise model involves two complementary approaches: dynamic noise after orbital tuning (DYNOT) and lag-1 autocorrelation coefficient (ρ 1 ). Noise modeling of Lower Triassic marine slope stratigraphy in South China reveal evidence for global sea-level variations in the Early Triassic hothouse that are anti-phased with continental water storage variations in the Germanic Basin. This supports the hypothesis that long-period (1-2 myr) astronomically forced water mass exchange between land and ocean reservoirs is a missing link for reconciling geological records and models for sea-level change during non-glacial periods.

  8. A High-Resolution Reconstruction of Late-Holocene Relative Sea Level in Rhode Island, USA

    Science.gov (United States)

    Stearns, R. B.; Engelhart, S. E.; Kemp, A.; Cahill, N.; Halavik, B. T.; Corbett, D. R.; Brain, M.; Hill, T. D.

    2017-12-01

    Studies on the US Atlantic and Gulf coasts have utilized salt-marsh peats and the macro- and microfossils preserved within them to reconstruct high-resolution records of relative sea level (RSL). We followed this approach to investigate spatial and temporal RSL variability in southern New England, USA, by reconstructing 3,300 years of RSL change in lower Narragansett Bay, Rhode Island. After reconnaisance of lower Narragansett Bay salt marshes, we recovered a 3.4m core at Fox Hill Marsh on Conanicut Island. We enumerated foraminiferal assemblages at 3cm intervals throughout the length of the core and we assessed trends in δ13C at 5 cm resolution. We developed a composite chronology (average resolution of ±50 years for a 1 cm slice) using 30 AMS radiocarbon dates and historical chronological markers of known age (137Cs, heavy metals, Pb isotopes, pollen). We assessed core compaction (mechanical compression) by collecting compaction-free basal-peat samples and using a published decompaction model. We employed fossil foraminifera and bulk sediment δ13C to estimate paleomarsh elevation using a Bayesian transfer function trained by a previously-published regional modern foraminiferal dataset. We combined the proxy RSL reconstruction and local tide-gauge measurements from Newport, Rhode Island (1931 CE to present) and estimated past rates of RSL change using an Errors-in-Variables Integrated Gaussian Process (EIV-IGP) model. Both basal peats and the decompaction model suggest that our RSL record is not significantly compacted. RSL rose from -3.9 m at 1250 BCE reaching -0.4 m at 1850 CE (1 mm/yr). We removed a Glacial Isostatic Adjustment (GIA) contribution of 0.9 mm/yr based on a local GPS site to facilitate comparison to regional records. The detrended sea-level reconstruction shows multiple departures from stable sea level (0 mm/yr) over the last 3,300 years and agrees with prior reconstructions from the US Atlantic coast showing evidence for sea-level changes that

  9. Cities and Sea Level Rise: A Roadmap for Flood Hazard Adaptation

    Science.gov (United States)

    Horn, D. P.; Cousins, A.

    2015-12-01

    Coastal cities will face a range of increasingly severe challenges as sea level rises, and adaptation to future flood risk will require more than structural defences. Many cities will not be able to rely solely on engineering structures for protection and will need to develop a suite of policy responses to increase their resilience to impacts of rising sea level. Local governments generally maintain day-to-day responsibility and control over the use of the vast majority of property at risk of flooding, and the tools to promote flood risk adaptation are already within the capacity of most cities. Policy tools available to address other land-use problems can be refashioned and used to adapt to sea level rise. This study reviews approaches for urban adaptation through case studies of cities which have developed flood adaptation strategies that combine structural defences with innovative approaches to living with flood risk. The aim of the overall project is to produce a 'roadmap' to guide practitioners through the process of analysing coastal flood risk in urban areas. Technical knowledge of flood risk reduction measures is complemented with a consideration of the essential impact that local policy has on the treatment of coastal flooding and the constraints and opportunities that result from the specific country or locality characteristics in relation to economic, political, social and environmental priorities, which are likely to dictate the approach to coastal flooding and the actions proposed. Detailed analyses of the adaptation strategies used by Rotterdam (Netherlands), Bristol (UK), and Norfolk (Virginia) are used to draw out a range of good practice elements that promote effective adaptation to sea level rise. These can be grouped into risk reduction, governance issues, and insurance, and can be used to provide examples of how other cities could adopt and implement flood adaptation strategies from a relatively limited starting position. Most cities will

  10. Decadal trends in deep ocean salinity and regional effects on steric sea level

    Science.gov (United States)

    Purkey, S. G.; Llovel, W.

    2017-12-01

    We present deep (below 2000 m) and abyssal (below 4000 m) global ocean salinity trends from the 1990s through the 2010s and assess the role of deep salinity in local and global sea level budgets. Deep salinity trends are assessed using all deep basins with available full-depth, high-quality hydrographic section data that have been occupied two or more times since the 1980s through either the World Ocean Circulation Experiment (WOCE) Hydrographic Program or the Global Ship-Based Hydrographic Investigations Program (GO-SHIP). All salinity data is calibrated to standard seawater and any intercruise offsets applied. While the global mean deep halosteric contribution to sea level rise is close to zero (-0.017 +/- 0.023 mm/yr below 4000 m), there is a large regional variability with the southern deep basins becoming fresher and northern deep basins becoming more saline. This meridional gradient in the deep salinity trend reflects different mechanisms driving the deep salinity variability. The deep Southern Ocean is freshening owing to a recent increased flux of freshwater to the deep ocean. Outside of the Southern Ocean, the deep salinity and temperature changes are tied to isopycnal heave associated with a falling of deep isopycnals in recent decades. Therefore, regions of the ocean with a deep salinity minimum are experiencing both a halosteric contraction with a thermosteric expansion. While the thermosteric expansion is larger in most cases, in some regions the halosteric compensates for as much as 50% of the deep thermal expansion, making a significant contribution to local sea level rise budgets.

  11. Atoll groundwater movement and its response to climatic and sea-level fluctuations

    Science.gov (United States)

    Oberle, Ferdinand; Swarzenski, Peter W.; Storlazzi, Curt

    2017-01-01

    Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall Islands. As part of a 16-month study, a rarely recorded island-overwash event occurred and the island’s aquifer’s response was measured. The findings suggest that small-scale overwash events cause an increase in salinity of the freshwater lens that returns to pre-overwash conditions within one month. The overwash event is addressed in the context of climate-related local sea-level change, which suggests that overwash events and associated degradations in freshwater resources are likely to increase in severity in the future due to projected rises in sea level. Other forcings, such as severe rainfall events, were shown to have caused a sudden freshening of the aquifer, with salinity levels retuning to pre-rainfall levels within three months. Tidal forcing of the freshwater lens was observed in electrical resistivity profiles, high-resolution conductivity, groundwater-level well measurements and through submarine groundwater discharge calculations. Depth-specific geochemical pore water measurements further assessed and confirmed the distinct boundaries between fresh and saline water masses in the aquifer. The identification of the freshwater lens’ saline boundaries is essential for a quantitative evaluation of the aquifers freshwater resources and help understand how these resources may be impacted by climate change and anthropogenic activities.

  12. Atoll Groundwater Movement and Its Response to Climatic and Sea-Level Fluctuations

    Directory of Open Access Journals (Sweden)

    Ferdinand K. J. Oberle

    2017-08-01

    Full Text Available Groundwater resources of low-lying atoll islands are threatened due to short-term and long-term changes in rainfall, wave climate, and sea level. A better understanding of how these forcings affect the limited groundwater resources was explored on Roi-Namur in the Republic of the Marshall Islands. As part of a 16-month study, a rarely recorded island-overwash event occurred and the island’s aquifer’s response was measured. The findings suggest that small-scale overwash events cause an increase in salinity of the freshwater lens that returns to pre-overwash conditions within one month. The overwash event is addressed in the context of climate-related local sea-level change, which suggests that overwash events and associated degradations in freshwater resources are likely to increase in severity in the future due to projected rises in sea level. Other forcings, such as severe rainfall events, were shown to have caused a sudden freshening of the aquifer, with salinity levels retuning to pre-rainfall levels within three months. Tidal forcing of the freshwater lens was observed in electrical resistivity profiles, high-resolution conductivity, groundwater-level well measurements and through submarine groundwater discharge calculations. Depth-specific geochemical pore water measurements further assessed and confirmed the distinct boundaries between fresh and saline water masses in the aquifer. The identification of the freshwater lens’ saline boundaries is essential for a quantitative evaluation of the aquifers freshwater resources and help understand how these resources may be impacted by climate change and anthropogenic activities.

  13. GPRS based real-time reporting and internet accessible sea level gauge for monitoring storm surge and tsunami

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, R.G.P.; Joseph, A.; Agarvadekar, Y.; Dabholkar, N.; Mehra, P.; Gouveia, A.D.; Tengali, S.; VijayKumar, K.; Parab, A.

    graphical illustration of the predicted fair-weather sea level, the current sea level, and the residual sea level (i.e., measured minus predicted fair-weather sea level). Thus, a cost-effective and easily maintainable platform is realized for real...

  14. Local and global: seafaring communities in the North Sea area, c. 1600-2000

    NARCIS (Netherlands)

    Davids, C.A.

    2015-01-01

    A seafaring community is a village, a small town or a neighbourhood where a substantial part of the population earns its livelihood wholly or partly by work at sea or is directly dependent on seafaring. A seafaring community can arise because an established population at a particular locality

  15. An Improved Local Gradient Method for Sea Surface Wind Direction Retrieval from SAR Imagery

    Directory of Open Access Journals (Sweden)

    Lizhang Zhou

    2017-06-01

    Full Text Available Sea surface wind affects the fluxes of energy, mass and momentum between the atmosphere and ocean, and therefore regional and global weather and climate. With various satellite microwave sensors, sea surface wind can be measured with large spatial coverage in almost all-weather conditions, day or night. Like any other remote sensing measurements, sea surface wind measurement is also indirect. Therefore, it is important to develop appropriate wind speed and direction retrieval models for different types of microwave instruments. In this paper, a new sea surface wind direction retrieval method from synthetic aperture radar (SAR imagery is developed. In the method, local gradients are computed in frequency domain by combining the operation of smoothing and computing local gradients in one step to simplify the process and avoid the difference approximation. This improved local gradients (ILG method is compared with the traditional two-dimensional fast Fourier transform (2D FFT method and local gradients (LG method, using interpolating wind directions from the European Centre for Medium-Range Weather Forecast (ECMWF reanalysis data and the Cross-Calibrated Multi-Platform (CCMP wind vector product. The sensitivities to the salt-and-pepper noise, the additive noise and the multiplicative noise are analyzed. The ILG method shows a better performance of retrieval wind directions than the other two methods.

  16. Atmospheric forcing on the seasonal variability of sea level at Cochin, southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, K.; DineshKumar, P.K.

    met-ocean parameters with observed sea level at Cochin, using long term time series data. Forty percent of the variance in the interannual sea level was accounted for by the along-shore wind stress. Statistical modelling of the monthly mean sea... level at fifteen different stations along the west and east coasts of the Indian subcontinent was attempted by Srinivas et al. (2005a) using autoregressive, sinusoidal and EWMA techniques. They also described in detail, statistics pertaining...

  17. Modeling Anthropogenic Impact on Sediment Balance and Relative Sea-Level Rise in Contemporary and Future Deltas

    Science.gov (United States)

    Tessler, Z. D.; Vorosmarty, C. J.; Overeem, I.; Syvitski, J. P.

    2017-12-01

    Modern deltas are dependent on human-mediated freshwater and sediment fluxes. Changes to these fluxes impact delta biogeophysical functioning, and affect the long-term sustainability of these landscapes for both human and natural systems. Here we present contemporary estimates of long-term mean sediment balance and relative sea-level rise across 46 global deltas. We model ongoing development and scenarios of future water resource management and hydropower infrastructure in upstream river basins to explore how changing sediment fluxes impact relative sea-level in coastal delta systems. Model results show that contemporary sediment fluxes, anthropogenic drivers of land subsidence, and sea-level rise result in relative sea-level rise rates in deltas that average 6.8 mm/year. Currently planned or under-construction dams can be expected to increase rates of relative sea-level rise on the order of 1 mm/year. Some deltas systems, including the Magdalena, Orinoco, and Indus, are highly sensitive to future impoundment of river basins, with RSLR rates increasing up to 4 mm/year in a high-hydropower-utilization scenario. Sediment fluxes may be reduced by up to 60% in the Danube and 21% in the Ganges-Brahmaputra-Megnha if all currently planned dams are constructed. Reduced sediment retention on deltas due to increased river channelization and local flood controls increases RSLR on average by nearly 2 mm/year. Long-term delta sustainability requires a more complete understanding of how geophysical and anthropogenic change impact delta geomorphology. Strategies for sustainable delta management that focus on local and regional drivers of change, especially groundwater and hydrocarbon extraction and upstream dam construction, can be highly impactful even in the context of global climate-induced sea-level rise.

  18. Revised paleoenvironmental analysis of the Holocene portion of the Barbados sea-level record: Cobbler's Reef revisited

    Science.gov (United States)

    Toscano, Marguerite A.

    2016-06-01

    Sample elevations corrected for tectonic uplift and assessed relative to local modeled sea levels provide a new perspective on paleoenvironmental history at Cobbler's Reef, Barbados. Previously, 14C-dated surface samples of fragmented Acropora palmata plotted above paleo sea level based on their present (uplifted) elevations, suggesting supratidal rubble deposited during a period of extreme storms (4500-3000 cal BP), precipitating reef demise. At several sites, however, A. palmata persisted, existing until ~370 cal BP. Uplift-corrected A. palmata sample elevations lie below the western Atlantic sea-level curve, and ~2 m below ICE-6G-modeled paleo sea level, under slow rates of sea-level rise, negating the possibility that Cobbler's Reef is a supratidal storm ridge. Most sites show limited age ranges from corals likely damaged/killed on the reef crest, not the mixed ages of rubble ridges, strongly suggesting the reef framework died off in stages over 6500 yr. Reef crest death assemblages invoke multiple paleohistoric causes, from ubiquitous hurricanes to anthropogenic impacts. Comparison of death assemblage ages to dated regional paleotempestological sequences, proxy-based paleotemperatures, recorded hurricanes, tsunamis, European settlement, deforestation, and resulting turbidity, reveals many possible factors inimical to the survival of A. palmata along Cobbler's Reef.

  19. Using simulations to forecast homeowner response to sea level rise in South Florida: Will they stay or will they go?

    Science.gov (United States)

    Treuer, G.

    2017-12-01

    Sea level rise threatens coastal communities around the world, including South Florida which may be the most financially vulnerable region in the world. Proactive investments in sea level rise adaptive flood protections could reduce South Florida's financial vulnerability. However, it is unclear if local governments and homeowners will be willing to make those investments before it is too late. Our research explores this issue by reporting the results of a novel online simulation that accelerates 348 South Florida homeowners thirty-five years into the future so that they can `live' the effects of sea level rise. The results contain a mix of optimism and caution for the prospects of future adaptation. On the positive side over 75% of participants indicated a willingness to support bond issues to pay for adaptation, even as the costs of the measures and effects of sea level rise increased over the years. Likewise, we find little evidence that politically conservative residents who normally have more skeptical views about climate change would be any less inclined to support adaptation, or only look to information sources that downplay the threat. On the negative side, homeowner interest in moving out of the region increases steadily over time as the sea level rises. This is driven by an increase in worry associated with viewing more information within the simulation.

  20. Observed sea-level rise in the north Indian Ocean coasts during the past century

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    Content-Type text/plain; charset=UTF-8 91 Observed sea-level rise in the north Indian Ocean coasts during the past century A. S. Unnikrishnan National Institute of Oceanography, Dona Paula, Goa-403004 unni@nio.org Introduction Sea-level... rise is one of the good indicators of global warming. Rise in sea level occurs mainly through melting of glaciers, thermal expansion due to ocean warming and some other processes of relatively smaller magnitudes. Sea level rise is a global...

  1. Robustness of observation-based decadal sea level variability in the Indo-Pacific Ocean

    Science.gov (United States)

    Nidheesh, A. G.; Lengaigne, M.; Vialard, J.; Izumo, T.; Unnikrishnan, A. S.; Meyssignac, B.; Hamlington, B.; de Boyer Montegut, C.

    2017-07-01

    We examine the consistency of Indo-Pacific decadal sea level variability in 10 gridded, observation-based sea level products for the 1960-2010 period. Decadal sea level variations are robust in the Pacific, with more than 50% of variance explained by decadal modulation of two flavors of El Niño-Southern Oscillation (classical ENSO and Modoki). Amplitude of decadal sea level variability is weaker in the Indian Ocean than in the Pacific. All data sets indicate a transmission of decadal sea level signals from the western Pacific to the northwest Australian coast through the Indonesian throughflow. The southern tropical Indian Ocean sea level variability is associated with decadal modulations of ENSO in reconstructions but not in reanalyses or in situ data set. The Pacific-independent Indian Ocean decadal sea level variability is not robust but tends to be maximum in the southwestern tropical Indian Ocean. The inconsistency of Indian Ocean decadal variability across the sea level products calls for caution in making definitive conclusions on decadal sea level variability in this basin.

  2. Current state and future perspectives on coupled ice-sheet - sea-level modelling

    Science.gov (United States)

    de Boer, Bas; Stocchi, Paolo; Whitehouse, Pippa L.; van de Wal, Roderik S. W.

    2017-08-01

    The interaction between ice-sheet growth and retreat and sea-level change has been an established field of research for many years. However, recent advances in numerical modelling have shed new light on the precise interaction of marine ice sheets with the change in near-field sea level, and the related stability of the grounding line position. Studies using fully coupled ice-sheet - sea-level models have shown that accounting for gravitationally self-consistent sea-level change will act to slow down the retreat and advance of marine ice-sheet grounding lines. Moreover, by simultaneously solving the 'sea-level equation' and modelling ice-sheet flow, coupled models provide a global field of relative sea-level change that is consistent with dynamic changes in ice-sheet extent. In this paper we present an overview of recent advances, possible caveats, methodologies and challenges involved in coupled ice-sheet - sea-level modelling. We conclude by presenting a first-order comparison between a suite of relative sea-level data and output from a coupled ice-sheet - sea-level model.

  3. Impacts of South East Biomass Burning on local air quality in South China Sea

    Science.gov (United States)

    Wai-man Yeung, Irene; Fat Lam, Yun; Eniolu Morakinyo, Tobi

    2016-04-01

    Biomass burning is a significant source of carbon monoxide and particulate matter, which is not only contribute to the local air pollution, but also regional air pollution. This study investigated the impacts of biomass burning emissions from Southeast Asia (SEA) as well as its contribution to the local air pollution in East and South China Sea, including Hong Kong and Taiwan. Three years (2012 - 2014) of the Hybrid Single Particle Lagrangian-Integrated Trajectory (HYSPLIT) with particles dispersion analyses using NCEP (Final) Operational Global Analysis data (FNL) data (2012 - 2014) were analyzed to track down all possible long-range transport from SEA with a sinking motion that worsened the surface air quality (tropospheric downwash from the free troposphere). The major sources of SEA biomass burning emissions were first identified using high fire emissions from the Global Fire Emission Database (GFED), followed by the HYSPLIT backward trajectory dispersion modeling analysis. The analyses were compared with the local observation data from Tai Mo Shan (1,000 msl) and Tap Mun (60 msl) in Hong Kong, as well as the data from Lulin mountain (2,600 msl) in Taiwan, to assess the possible impacts of SEA biomass burning on local air quality. The correlation between long-range transport events from the particles dispersion results and locally observed air quality data indicated that the background concentrations of ozone, PM2.5 and PM10 at the surface stations were enhanced by 12 μg/m3, 4 μg/m3 and 7 μg/m3, respectively, while the long-range transport contributed to enhancements of 4 μg/m3, 4 μg/m3 and 8 μg/m3 for O3, PM2.5 and PM10, respectively at the lower free atmosphere.

  4. Mapping Sea Level Rise Behavior in an Estuarine Delta System: A Case Study along the Shanghai Coast

    Directory of Open Access Journals (Sweden)

    H.Q. Cheng

    2018-02-01

    Full Text Available Sea level rise (SLR is a major projected threat of climate change that is expected to affect developing coastal cities located in estuarine delta regions. Shanghai is one such city, being located in the Yangtze River Delta (YRD. It is difficult, however, for decision-makers to implement adaptation due to the uncertain causes, magnitudes, and timings of SLR behaviors. This paper attempts to map the causes and magnitudes of SLR behaviors on a decadal scale. We analyze the tidal level records from 11 tidal gauge stations and the corresponding bathymetry measurements around these stations since 1921. We identify three new SLR behaviors along the Shanghai coast due to anthropogenic geomorphologic changes (AGCs, besides the well-known eustatic sea level rise (ESLR, tectonic subsidence (TS, and urban land subsidence (ULS. The first new behavior is regional sea level rise (RSLR, which occurs as a result of land reclamation and deep waterway regulation. The second is regional sea level fall (RSLF, which occurs because the channel bed is eroded due to sediment supply decline in the river catchment. The last SLR behavior is local tidal datum rise (LTDR. Thus, we project that the magnitude of SLR for the Shanghai coast ranges from 10 cm to 16 cm from 2011 to 2030. Clarifying SLR behaviors is important to aid local decision-makers in planning structural and non-structural measures to combat escalating flood damage costs in an estuarine delta system; this field is full of future challenges. Keywords: Sea level rise behavior, Anthropogenic geomorphologic change, Local tidal datum, Flood management, Adaptation

  5. Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones.

    Science.gov (United States)

    Moran, Yehu; Genikhovich, Grigory; Gordon, Dalia; Wienkoop, Stefanie; Zenkert, Claudia; Ozbek, Suat; Technau, Ulrich; Gurevitz, Michael

    2012-04-07

    Jellyfish, hydras, corals and sea anemones (phylum Cnidaria) are known for their venomous stinging cells, nematocytes, used for prey and defence. Here we show, however, that the potent Type I neurotoxin of the sea anemone Nematostella vectensis, Nv1, is confined to ectodermal gland cells rather than nematocytes. We demonstrate massive Nv1 secretion upon encounter with a crustacean prey. Concomitant discharge of nematocysts probably pierces the prey, expediting toxin penetration. Toxin efficiency in sea water is further demonstrated by the rapid paralysis of fish or crustacean larvae upon application of recombinant Nv1 into their medium. Analysis of other anemone species reveals that in Anthopleura elegantissima, Type I neurotoxins also appear in gland cells, whereas in the common species Anemonia viridis, Type I toxins are localized to both nematocytes and ectodermal gland cells. The nematocyte-based and gland cell-based envenomation mechanisms may reflect substantial differences in the ecology and feeding habits of sea anemone species. Overall, the immunolocalization of neurotoxins to gland cells changes the common view in the literature that sea anemone neurotoxins are produced and delivered only by stinging nematocytes, and raises the possibility that this toxin-secretion mechanism is an ancestral evolutionary state of the venom delivery machinery in sea anemones.

  6. Modelling the increased frequency of extreme sea levels in the Ganges-Brahmaputra-Meghna delta due to sea level rise and other effects of climate change.

    Science.gov (United States)

    Kay, S; Caesar, J; Wolf, J; Bricheno, L; Nicholls, R J; Saiful Islam, A K M; Haque, A; Pardaens, A; Lowe, J A

    2015-07-01

    Coastal flooding due to storm surge and high tides is a serious risk for inhabitants of the Ganges-Brahmaputra-Meghna (GBM) delta, as much of the land is close to sea level. Climate change could lead to large areas of land being subject to increased flooding, salinization and ultimate abandonment in West Bengal, India, and Bangladesh. IPCC 5th assessment modelling of sea level rise and estimates of subsidence rates from the EU IMPACT2C project suggest that sea level in the GBM delta region may rise by 0.63 to 0.88 m by 2090, with some studies suggesting this could be up to 0.5 m higher if potential substantial melting of the West Antarctic ice sheet is included. These sea level rise scenarios lead to increased frequency of high water coastal events. Any effect of climate change on the frequency and severity of storms can also have an effect on extreme sea levels. A shelf-sea model of the Bay of Bengal has been used to investigate how the combined effect of sea level rise and changes in other environmental conditions under climate change may alter the frequency of extreme sea level events for the period 1971 to 2099. The model was forced using atmospheric and oceanic boundary conditions derived from climate model projections and the future scenario increase in sea level was applied at its ocean boundary. The model results show an increased likelihood of extreme sea level events through the 21st century, with the frequency of events increasing greatly in the second half of the century: water levels that occurred at decadal time intervals under present-day model conditions occurred in most years by the middle of the 21st century and 3-15 times per year by 2100. The heights of the most extreme events tend to increase more in the first half of the century than the second. The modelled scenarios provide a case study of how sea level rise and other effects of climate change may combine to produce a greatly increased threat to life and property in the GBM delta by the end

  7. Sea Level Trend and Variability in the Straits of Singapore and Malacca

    Science.gov (United States)

    Luu, Q.; Tkalich, P.

    2013-12-01

    The Straits of Singapore and Malacca (SSM) connect the Andaman Sea located northeast of the Indian Ocean to the South China Sea, the largest marginal sea situated in the tropical Pacific Ocean. Consequently, sea level in the SSM is assumed to be governed by various regional phenomena associated with the adjacent parts of Indian and Pacific Oceans. At annual scale sea level variability is dominant by the Asian monsoon. Interannual sea level signals are modulated by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). In the long term, regional sea level is driven by the global climate change. However, relative impacts of these multi-scale phenomena on regional sea level in the SSM are yet to be quantified. In present study, publicly available tide gauge records and satellite altimetry data are used to derive long-term sea level trend and variability in SSM. We used the data from research-quality stations, including four located in the Singapore Strait (Tanjong Pagar, Raffles Lighthouse, Sultan Shoal and Sembawang) and seven situated in the Malacca Strait (Kelang, Keling, Kukup, Langkawji, Lumut, Penang and Ko Taphao Noi), each one having 25-39 year data up to the year 2011. Harmonic analysis is performed to filter out astronomic tides from the tide gauge records when necessary; and missing data are reconstructed using identified relationships between sea level and the governing phenomena. The obtained sea level anomalies (SLAs) and reconstructed mean sea level are then validated against satellite altimetry data from AVISO. At multi-decadal scale, annual measured sea level in the SSM is varying with global mean sea level, rising for the period 1984-2009 at the rate 1.8-2.3 mm/year in the Singapore Strait and 1.1-2.8 mm/year in the Malacca Strait. Interannual regional sea level drops are associated with El Niño events, while the rises are correlated with La Niña episodes; both variations are in the range of ×5 cm with correlation coefficient

  8. Evolution of the Rømø barrier island in the Wadden Sea: Impacts of sea-level change on coastal morphodynamics

    DEFF Research Database (Denmark)

    Clemmensen, Lars B; Andersen, Thorbjørn Joest; Johannessen, Peter

    , and falling sea-level, whereas wash-over sedimentation was promoted during periods of rapid sea-level rise when shoreface, beach and coastal dune deposits were reworked. In contrast, lagoonal sedimentation has been relatively continuous and kept pace with the long-term Holocene sea-level rise. Our findings...

  9. Sea level and turbidity controls on mangrove soil surface elevation change

    Science.gov (United States)

    Lovelock, Catherine E.; Fernanda Adame, Maria; Bennion, Vicki; Hayes, Matthew; Reef, Ruth; Santini, Nadia; Cahoon, Donald R.

    2015-01-01

    Increases in sea level are a threat to seaward fringing mangrove forests if levels of inundation exceed the physiological tolerance of the trees; however, tidal wetlands can keep pace with sea level rise if soil surface elevations can increase at the same pace as sea level rise. Sediment accretion on the soil surface and belowground production of roots are proposed to increase with increasing sea level, enabling intertidal habitats to maintain their position relative to mean sea level, but there are few tests of these predictions in mangrove forests. Here we used variation in sea level and the availability of sediments caused by seasonal and inter-annual variation in the intensity of La Nina-El Nino to assess the effects of increasing sea level on surface elevation gains and contributing processes (accretion on the surface, subsidence and root growth) in mangrove forests. We found that soil surface elevation increased with mean sea level (which varied over 250 mm during the study) and with turbidity at sites where fine sediment in the water column is abundant. In contrast, where sediments were sandy, rates of surface elevation gain were high, but not significantly related to variation in turbidity, and were likely to be influenced by other factors that deliver sand to the mangrove forest. Root growth was not linked to soil surface elevation gains, although it was associated with reduced shallow subsidence, and therefore may contribute to the capacity of mangroves to keep pace with sea level rise. Our results indicate both surface (sedimentation) and subsurface (root growth) processes can influence mangrove capacity to keep pace with sea level rise within the same geographic location, and that current models of tidal marsh responses to sea level rise capture the major feature of the response of mangroves where fine, but not coarse, sediments are abundant.

  10. Coastal Sea Level from CryoSat-2 SARIn Altimetry in Norway

    DEFF Research Database (Denmark)

    Idžanović, Martina; Ophaug, Vegard; Andersen, Ole Baltazar

    2017-01-01

    Conventional (pulse-limited) altimeters determine the sea surface height with an accuracy of a few centimeters over the open ocean. Sea surface heights and tide-gauge sea level serve as each other’s buddy check. However, in coastal areas, altimetry suffers from numerous effects, which degrade its...... conventional altimeters. In this study, we explore the potential of CryoSat-2 to provide valid observations in the Norwegian coastal zone. We do this by comparing time series of CryoSat-2 sea level anomalies with time series of in situ sea level at 22 tide gauges, where the CryoSat-2 sea level anomalies...... are averaged in a 45-km area around each tide gauge. For all tide gauges, CryoSat-2 shows standard deviations of differences and correlations of 16 cm and 61%, respectively. We further identify the ocean tide and inverted barometer geophysical corrections as the most crucial, and note that a large amount...

  11. Non-linear interactions determine the impact of sea-level rise on estuarine benthic biodiversity and ecosystem processes.

    Science.gov (United States)

    Yamanaka, Tsuyuko; Raffaelli, David; White, Piran C L

    2013-01-01

    Sea-level rise induced by climate change may have significant impacts on the ecosystem functions and ecosystem services provided by intertidal sediment ecosystems. Accelerated sea-level rise is expected to lead to steeper beach slopes, coarser particle sizes and increased wave exposure, with consequent impacts on intertidal ecosystems. We examined the relationships between abundance, biomass, and community metabolism of benthic fauna with beach slope, particle size and exposure, using samples across a range of conditions from three different locations in the UK, to determine the significance of sediment particle size beach slope and wave exposure in affecting benthic fauna and ecosystem function in different ecological contexts. Our results show that abundance, biomass and oxygen consumption of intertidal macrofauna and meiofauna are affected significantly by interactions among sediment particle size, beach slope and wave exposure. For macrofauna on less sloping beaches, the effect of these physical constraints is mediated by the local context, although for meiofauna and for macrofauna on intermediate and steeper beaches, the effects of physical constraints dominate. Steeper beach slopes, coarser particle sizes and increased wave exposure generally result in decreases in abundance, biomass and oxygen consumption, but these relationships are complex and non-linear. Sea-level rise is likely to lead to changes in ecosystem structure with generally negative impacts on ecosystem functions and ecosystem services. However, the impacts of sea-level rise will also be affected by local ecological context, especially for less sloping beaches.

  12. Predicting habitat distribution to conserve seagrass threatened by sea level rise

    Science.gov (United States)

    Saunders, M. I.; Baldock, T.; Brown, C. J.; Callaghan, D. P.; Golshani, A.; Hamylton, S.; Hoegh-guldberg, O.; Leon, J. X.; Lovelock, C. E.; Lyons, M. B.; O'Brien, K.; Mumby, P.; Phinn, S. R.; Roelfsema, C. M.

    2013-12-01

    Sea level rise (SLR) over the 21st century will cause significant redistribution of valuable coastal habitats. Seagrasses form extensive and highly productive meadows in shallow coastal seas support high biodiversity, including economically valuable and threatened species. Predictive habitat models can inform local management actions that will be required to conserve seagrass faced with multiple stressors. We developed novel modelling approaches, based on extensive field data sets, to examine the effects of sea level rise and other stressors on two representative seagrass habitats in Australia. First, we modelled interactive effects of SLR, water clarity and adjacent land use on estuarine seagrass meadows in Moreton Bay, Southeast Queensland. The extent of suitable seagrass habitat was predicted to decline by 17% by 2100 due to SLR alone, but losses were predicted to be significantly reduced through improvements in water quality (Fig 1a) and by allowing space for seagrass migration with inundation. The rate of sedimentation in seagrass strongly affected the area of suitable habitat for seagrass in sea level rise scenarios (Fig 1b). Further research to understand spatial, temporal and environmental variability of sediment accretion in seagrass is required. Second, we modelled changes in wave energy distribution due to predicted SLR in a linked coral reef and seagrass ecosystem at Lizard Island, Great Barrier Reef. Scenarios where the water depth over the coral reef deepened due to SLR and minimal reef accretion, resulted in larger waves propagating shoreward, changing the existing hydrodynamic conditions sufficiently to reduce area of suitable habitat for seagrass. In a scenario where accretion of the coral reef was severely compromised (e.g. warming, acidification, overfishing), the probability of the presence of seagrass declined significantly. Management to maintain coral health will therefore also benefit seagrasses subject to SLR in reef environments. Further

  13. Indo-Pacific sea level variability at multidecadal time scales

    Science.gov (United States)

    Merrifield, M. A.; Thompson, P. R.

    2016-12-01

    Long tide gauge and atmospheric pressure measurements are used to infer multidecadal fluctuations in trade wind forcing and the associated Indo-Pacific sea level response along coastal and equatorial waveguides. The trade wind variations are marked by a weakening beginning with the late 1970s climate shift and a subsequent return to mean conditions since the early 1990s. These fluctuations covary with multidecadal wind changes at mid-latitudes, as measured by the Pacific Decadal Oscillation or the North Pacific indices; however, the mid-latitude multidecadal variations prior to 1970 or noticeably absent in the inferred trade wind record. The different behavior of tropical and mid-latitude winds support the notion that multidecadal climate variations in the Pacific result from a combination of processes and not a single coherent mode spanning the basin. In particular, the two-decade long satellite altimeter record represents a period of apparent connection between the two regions that was not exhibited earlier in the century.

  14. Trends in Intense Typhoon Minimum Sea Level Pressure

    Directory of Open Access Journals (Sweden)

    Stephen L. Durden

    2012-01-01

    Full Text Available A number of recent publications have examined trends in the maximum wind speed of tropical cyclones in various basins. In this communication, the author focuses on typhoons in the western North Pacific. Rather than maximum wind speed, the intensity of the storms is measured by their lifetime minimum sea level pressure (MSLP. Quantile regression is used to test for trends in storms of extreme intensity. The results indicate that there is a trend of decreasing intensity in the most intense storms as measured by MSLP over the period 1951–2010. However, when the data are broken into intervals 1951–1987 and 1987–2010, neither interval has a significant trend, but the intensity quantiles for the two periods differ. Reasons for this are discussed, including the cessation of aircraft reconnaissance in 1987. The author also finds that the average typhoon intensity is greater in El Nino years, while the intensity of the strongest typhoons shows no significant relation to El Nino Southern Oscillation.

  15. Holocene relative sea-level changes from North America and the Caribbean

    Science.gov (United States)

    Horton, Benjamin; Engelhart, Simon; Vacchi, Matteo; Khan, Nicole; Peltier, Dick; Roy, Keven

    2014-05-01

    Reconstructions of Holocene relative sea level (RSL) are important for identifying the ice equivalent meltwater contribution to sea-level change during deglaciation. Holocene RSL reconstructions from near, intermediate and far field regions enable the assessment of earth and ice parameters of Glacial Isostatic Adjustment (GIA) models. RSL reconstructions provide data for estimating rates of spatially variable and ongoing vertical land motion; a requirement for understanding the variation in modern and late Holocene sea level as recorded by instrumental and proxy records. Here we explain the methodology employed to reconstruct former sea levels, which follows the practice of the International Geoscience Programme (IGCP). We produce sea level index points from the Pacific and Atlantic coasts of North America and the Caribbean. Index points are defined as the most reliable observations of former sea levels. They consist of an estimate of X (age) and Y (the position of former RSL). Where a suite of index points are developed for a locality or region, they describe changes in RSL through time and estimate rates of change. A valid index point must meet the following four criteria; (1) location of the sample is known; (2) the altitude of the sample (and the error associated with measuring that altitude) is known; (3) the indicative meaning (the relationship between the sample and a tide level) is estimated; and (4) the age of the sample, which is commonly radiocarbon dated is calibrated to sidereal years using the latest calibration curves. In total databases have over 2000 sea-level index points from formerly ice covered, uplifting regions of Canada, to the region of forebulge collapse along the subsiding mid-Atlantic and mid-Pacific coastlines of the United States, to the tropical regions of the Caribbean. Recent analyses of these new published databases have led to a further refinement of the most recent of the ICE-NG (VMX) series of global models of GIA. The records

  16. A Mid-Holocene Relative Sea-Level Stack, New Jersey, USA

    Science.gov (United States)

    Horton, B.; Walker, J. S.; Kemp, A.; Shaw, T. J.; Kopp, R. E.

    2017-12-01

    Most high resolution (decimeter- and decadal-scale) relative sea-level (RSL) records using salt-marsh microfossils as a proxy only extend through the Common Era, limiting our understanding of driving mechanisms of RSL change and how sea-level is influenced by changing climate. Records beyond the Common Era are limited by the depth of continuous sequences of salt-marsh peat suitable for high resolution reconstructions, as well as contamination by local processes such as sediment compaction. In contrast, sequences of basal peats have produced compaction-free RSL records through the Holocene, but at a low resolution (meter- and centennial-scale). We devise a new Multi-Proxy Presence/Absence Method (MP2AM) to develop a mid-Holocene RSL stack. We stack a series of 1 m basal peat cores that overlap along a uniform elevational gradient above an incompressible basal sand. We analyzed three sea-level indicators from 14 cores: foraminifera, testate amoebae, and stable carbon isotope geochemistry. To reconstruct RSL, this multi-proxy approach uses the timesaving presence/absence of forams and testates to determine the elevation of the highest occurrence of forams and the lowest occurrence of testates in each basal core. We use stable carbon isotope geochemistry to determine the C3/C4 vegetation boundary in each core. We develop age-depth models for each core using a series of radiocarbon dates. The RSL records from each 1 m basal core are combined to create a stack or, in effect, one long core of salt-marsh material. This method removes the issue of compaction to create a continuous RSL record to address temporal changes and periods of climate and sea-level variability. We reconstruct a southern NJ mid-Holocene RSL record from Edwin B. Forsythe National Wildlife Refuge, where Kemp et al. (2013) completed a 2500 yr RSL record using a foraminifera-based transfer function approach. Preliminary radiocarbon dates suggest the basal sequence is at least 4246-4408 cal yrs BP

  17. Steric and mass-induced Mediterranean sea level trends from 14 years of altimetry data

    Science.gov (United States)

    Criado-Aldeanueva, Francisco; Del Río Vera, Jorge; García-Lafuente, Jesús

    2008-02-01

    Long-term series of almost 14 years of altimetry data (1992-2005) have been analysed along with Sea Surface Temperature (SST) and temperature and salinity profiles to investigate sea level trends over the Mediterranean Sea. Although sea level variations are mainly driven by the steric contribution, the mass-induced component plays some role in modulating its oscillation. A spatially averaged positive trend of 2.1 ± 0.6 mm/year has been observed, but a change in sign in 2001 seems to appear. Steric effects (mainly on thermal origin) account for ˜ 55% of sea level trend. Although Mediterranean Sea is a semi-enclosed basin, this value is comparable to that reported for the global ocean. Sea level rise is particularly important in the Levantine basin south of Crete with values up to 10 ± 1 mm/year. Other areas of sea level rise are localised throughout the Levantine basin and in the Adriatic and Alboran Seas, with more moderate values. Sea level drop areas are localised in the Algerian basin, between the Balearic Islands and the African coasts and, particularly, in the Ionian basin. In this area, negative trends as high as - 10 ± 0.8 mm/year are detected mainly due to the mass-induced contribution, which suggests decadal changes of surface circulation. The inferred sea level trends have been correlated with North Atlantic Oscillation (NAO) indices and a low but significant correlation has been detected between sea level in the Levantine and Balearic basins and NAO index.

  18. Arctic Sea Level Change over the altimetry era and reconstructed over the last 60 years

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Svendsen, Peter Limkilde; Nielsen, Allan Aasbjerg

    The Arctic Ocean process severe limitations on the use of altimetry and tide gauge data for sea level studies and prediction due to the presence of seasonal or permanent sea ice. In order to overcome this issue we reprocessed all altimetry data with editing tailored to Arctic conditions, hereby m...... by Church and White (2004). We also find significant higher trend in the Beaufort Gyre region showing an increase in sea level over the last decade up to 2011....

  19. Ensemble-based evaluation of extreme water levels for the eastern Baltic Sea

    Science.gov (United States)

    Eelsalu, Maris; Soomere, Tarmo

    2016-04-01

    The risks and damages associated with coastal flooding that are naturally associated with an increase in the magnitude of extreme storm surges are one of the largest concerns of countries with extensive low-lying nearshore areas. The relevant risks are even more contrast for semi-enclosed water bodies such as the Baltic Sea where subtidal (weekly-scale) variations in the water volume of the sea substantially contribute to the water level and lead to large spreading of projections of future extreme water levels. We explore the options for using large ensembles of projections to more reliably evaluate return periods of extreme water levels. Single projections of the ensemble are constructed by means of fitting several sets of block maxima with various extreme value distributions. The ensemble is based on two simulated data sets produced in the Swedish Meteorological and Hydrological Institute. A hindcast by the Rossby Centre Ocean model is sampled with a resolution of 6 h and a similar hindcast by the circulation model NEMO with a resolution of 1 h. As the annual maxima of water levels in the Baltic Sea are not always uncorrelated, we employ maxima for calendar years and for stormy seasons. As the shape parameter of the Generalised Extreme Value distribution changes its sign and substantially varies in magnitude along the eastern coast of the Baltic Sea, the use of a single distribution for the entire coast is inappropriate. The ensemble involves projections based on the Generalised Extreme Value, Gumbel and Weibull distributions. The parameters of these distributions are evaluated using three different ways: maximum likelihood method and method of moments based on both biased and unbiased estimates. The total number of projections in the ensemble is 40. As some of the resulting estimates contain limited additional information, the members of pairs of projections that are highly correlated are assigned weights 0.6. A comparison of the ensemble-based projection of

  20. Planning Workshop on Local Level Poverty Monitoring System

    International Development Research Centre (IDRC) Digital Library (Canada)

    Md. Abdul Quader - Ranjan Kumar Guha

    decision making and incorporate these in preparing the development plans and programmes of the ... and highlight the usefulness of the information in local level planning. The aim ..... proper accounts of the cooperatives for its sustainability.

  1. Future sea level rise constrained by observations and long-term commitment

    Science.gov (United States)

    Mengel, Matthias; Levermann, Anders; Frieler, Katja; Robinson, Alexander; Marzeion, Ben; Winkelmann, Ricarda

    2016-01-01

    Sea level has been steadily rising over the past century, predominantly due to anthropogenic climate change. The rate of sea level rise will keep increasing with continued global warming, and, even if temperatures are stabilized through the phasing out of greenhouse gas emissions, sea level is still expected to rise for centuries. This will affect coastal areas worldwide, and robust projections are needed to assess mitigation options and guide adaptation measures. Here we combine the equilibrium response of the main sea level rise contributions with their last century's observed contribution to constrain projections of future sea level rise. Our model is calibrated to a set of observations for each contribution, and the observational and climate uncertainties are combined to produce uncertainty ranges for 21st century sea level rise. We project anthropogenic sea level rise of 28–56 cm, 37–77 cm, and 57–131 cm in 2100 for the greenhouse gas concentration scenarios RCP26, RCP45, and RCP85, respectively. Our uncertainty ranges for total sea level rise overlap with the process-based estimates of the Intergovernmental Panel on Climate Change. The “constrained extrapolation” approach generalizes earlier global semiempirical models and may therefore lead to a better understanding of the discrepancies with process-based projections. PMID:26903648

  2. Sea-level rise caused by climate change and its implications for society

    Science.gov (United States)

    MIMURA, Nobuo

    2013-01-01

    Sea-level rise is a major effect of climate change. It has drawn international attention, because higher sea levels in the future would cause serious impacts in various parts of the world. There are questions associated with sea-level rise which science needs to answer. To what extent did climate change contribute to sea-level rise in the past? How much will global mean sea level increase in the future? How serious are the impacts of the anticipated sea-level rise likely to be, and can human society respond to them? This paper aims to answer these questions through a comprehensive review of the relevant literature. First, the present status of observed sea-level rise, analyses of its causes, and future projections are summarized. Then the impacts are examined along with other consequences of climate change, from both global and Japanese perspectives. Finally, responses to adverse impacts will be discussed in order to clarify the implications of the sea-level rise issue for human society. PMID:23883609

  3. Coastal sensitivity to sea level rise : a focus on the mid-atlantic region

    Science.gov (United States)

    2009-01-15

    The focus of this product is to identify and review the potential impacts of future sea-level rise based on present scientific understanding. To do so, this product evaluates : several aspects of sea-level rise impacts to the natural environment and ...

  4. Sea Level Activities and Changes on the Islands of the Western ...

    African Journals Online (AJOL)

    1985- 1994), a sea-level study network was established in the Western Indian Ocean (WIO) to monitor sea-level variations. Most of these stations together with additional stations maintained by countries outside the region now form part of the ...

  5. Understanding extreme sea levels for broad-scale coastal impact and adaptation analysis

    NARCIS (Netherlands)

    Wahl, T.; Haigh, I.D.; Nicholls, R.J.; Arns, A.; Dangendorf, S.; Hinkel, J.; Slangen, A.B.A.

    2017-01-01

    One of the main consequences of mean sea level rise (SLR) on human settlements is an increase in flood risk due to an increase in the intensity and frequency of extreme sea levels (ESL). While substantial research efforts are directed towards quantifying projections and uncertainties of future

  6. Sea-level rise caused by climate change and its implications for society.

    Science.gov (United States)

    Mimura, Nobuo

    2013-01-01

    Sea-level rise is a major effect of climate change. It has drawn international attention, because higher sea levels in the future would cause serious impacts in various parts of the world. There are questions associated with sea-level rise which science needs to answer. To what extent did climate change contribute to sea-level rise in the past? How much will global mean sea level increase in the future? How serious are the impacts of the anticipated sea-level rise likely to be, and can human society respond to them? This paper aims to answer these questions through a comprehensive review of the relevant literature. First, the present status of observed sea-level rise, analyses of its causes, and future projections are summarized. Then the impacts are examined along with other consequences of climate change, from both global and Japanese perspectives. Finally, responses to adverse impacts will be discussed in order to clarify the implications of the sea-level rise issue for human society.(Communicated by Kiyoshi HORIKAWA, M.J.A.).

  7. Future sea level rise constrained by observations and long-term commitment.

    Science.gov (United States)

    Mengel, Matthias; Levermann, Anders; Frieler, Katja; Robinson, Alexander; Marzeion, Ben; Winkelmann, Ricarda

    2016-03-08

    Sea level has been steadily rising over the past century, predominantly due to anthropogenic climate change. The rate of sea level rise will keep increasing with continued global warming, and, even if temperatures are stabilized through the phasing out of greenhouse gas emissions, sea level is still expected to rise for centuries. This will affect coastal areas worldwide, and robust projections are needed to assess mitigation options and guide adaptation measures. Here we combine the equilibrium response of the main sea level rise contributions with their last century's observed contribution to constrain projections of future sea level rise. Our model is calibrated to a set of observations for each contribution, and the observational and climate uncertainties are combined to produce uncertainty ranges for 21st century sea level rise. We project anthropogenic sea level rise of 28-56 cm, 37-77 cm, and 57-131 cm in 2100 for the greenhouse gas concentration scenarios RCP26, RCP45, and RCP85, respectively. Our uncertainty ranges for total sea level rise overlap with the process-based estimates of the Intergovernmental Panel on Climate Change. The "constrained extrapolation" approach generalizes earlier global semiempirical models and may therefore lead to a better understanding of the discrepancies with process-based projections.

  8. Sea-level Rise Impacts on Oregon Estuaries: Biology and Hydrology

    Science.gov (United States)

    Estuaries are transitional ecosystems located at the margin of the land and ocean and as a result they are particularly sensitive to sea level rise and other climate drivers. In this presentation, we summarize the potential impacts of sea level rise on key estuarine habitats inc...

  9. Sea-level Rise Impacts on Oregon Estuaries: Biology and Hydrology - for posting on website

    Science.gov (United States)

    Estuaries are transitional ecosystems located at the margin of the land and ocean and as a result they are particularly sensitive to sea level rise and other climate drivers. In this presentation, we summarize the potential impacts of sea level rise on key estuarine habitats incl...

  10. On the regional characteristics of past and future sea-level change (Invited)

    Science.gov (United States)

    Timmermann, A.; McGregor, S.

    2010-12-01

    Global sea-level rise due to the thermal expansion of the warming oceans and freshwater input from melting glaciers and ice-sheets is threatening to inundate low-lying islands and coast-lines worldwide. At present global mean sea level rises at 3.1 ± 0.7 mm/yr with an accelerating tendency. However, the magnitude of recent decadal sea-level trends varies greatly spatially attaining values of up to 10 mm/yr in some areas of the western tropical Pacific. Identifying the causes of recent regional sea-level trends and understanding the patterns of future projected sea-level change is of crucial importance. Using a wind-forced simplified dynamical ocean model, we show that the regional features of recent decadal and multidecadal sea-level trends in the tropical Indo-Pacific can be attributed to changes in the prevailing wind-regimes. Furthermore it is demonstrated that within an ensemble of ten state-of-the art coupled general circulation models, forced by increasing atmospheric CO2 concentrations over the next century, wind-induced re-distributions of upper-ocean water play a key role in establishing the spatial characteristics of projected regional sea-level rise. Wind-related changes in near- surface mass and heat convergence near the Solomon Islands, Tuvalu, Kiribati, the Cook Islands and French Polynesia oppose, but can not cancel the regional signal of global mean sea-level rise.

  11. Current state and future perspectives on coupled ice-sheet – sea-level modelling

    NARCIS (Netherlands)

    de Boer, Bas; Stocchi, Paolo; Whitehouse, Pippa L.; van de Wal, Roderik S.W.

    2017-01-01

    The interaction between ice-sheet growth and retreat and sea-level change has been an established field of research for many years. However, recent advances in numerical modelling have shed new light on the precise interaction of marine ice sheets with the change in near-field sea level, and the

  12. Coastal barrier stratigraphy for Holocene high-resolution sea-level reconstruction.

    Science.gov (United States)

    Costas, Susana; Ferreira, Óscar; Plomaritis, Theocharis A; Leorri, Eduardo

    2016-12-08

    The uncertainties surrounding present and future sea-level rise have revived the debate around sea-level changes through the deglaciation and mid- to late Holocene, from which arises a need for high-quality reconstructions of regional sea level. Here, we explore the stratigraphy of a sandy barrier to identify the best sea-level indicators and provide a new sea-level reconstruction for the central Portuguese coast over the past 6.5 ka. The selected indicators represent morphological features extracted from coastal barrier stratigraphy, beach berm and dune-beach contact. These features were mapped from high-resolution ground penetrating radar images of the subsurface and transformed into sea-level indicators through comparison with modern analogs and a chronology based on optically stimulated luminescence ages. Our reconstructions document a continuous but slow sea-level rise after 6.5 ka with an accumulated change in elevation of about 2 m. In the context of SW Europe, our results show good agreement with previous studies, including the Tagus isostatic model, with minor discrepancies that demand further improvement of regional models. This work reinforces the potential of barrier indicators to accurately reconstruct high-resolution mid- to late Holocene sea-level changes through simple approaches.

  13. Estimating absolute sea level variations by combining GNSS and Tide gauge data

    Digital Repository Service at National Institute of Oceanography (India)

    Bos, M.S.; Fernandes, R.M.S; Vethamony, P.; Mehra, P.

    Indian tide gauges can be used to estimate sea level rise. To separate relative sea level rise from vertical land motion at the tide gauges, various GNSS stations have been installed in the last years at, or nearby, tide gauges. Using the PSMSL...

  14. Monthly Variations in Sea Level at the Island of Zanzibar | Mahongo ...

    African Journals Online (AJOL)

    Western Indian Ocean Journal of Marine Science ... Air pressure and rainfall remained relatively constant during the 20-year study period, but there were trends in sea level, northeast winds, southeast winds and air temperature. Monthly ... The trend in sea level (9%) appeared to be mainly correlated with northeast winds.

  15. The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600)

    Science.gov (United States)

    Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

    2013-01-01

    Background Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Methods Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. Results The Australians’ sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians’ sleep tended to be better than that of the Australians at altitude. Conclusions Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives. PMID:24282197

  16. The sleep of elite athletes at sea level and high altitude: a comparison of sea-level natives and high-altitude natives (ISA3600).

    Science.gov (United States)

    Roach, Gregory D; Schmidt, Walter F; Aughey, Robert J; Bourdon, Pitre C; Soria, Rudy; Claros, Jesus C Jimenez; Garvican-Lewis, Laura A; Buchheit, Martin; Simpson, Ben M; Hammond, Kristal; Kley, Marlen; Wachsmuth, Nadine; Gore, Christopher J; Sargent, Charli

    2013-12-01

    Altitude exposure causes acute sleep disruption in non-athletes, but little is known about its effects in elite athletes. The aim of this study was to examine the effects of altitude on two groups of elite athletes, that is, sea-level natives and high-altitude natives. Sea-level natives were members of the Australian under-17 soccer team (n=14). High-altitude natives were members of a Bolivian under-20 club team (n=12). Teams participated in an 18-day (19 nights) training camp in Bolivia, with 6 nights at near sea level in Santa Cruz (430 m) and 13 nights at high altitude in La Paz (3600 m). Sleep was assessed on every day/night using activity monitors. The Australians' sleep was shorter, and of poorer quality, on the first night at altitude compared with sea level. Sleep quality returned to normal by the end of the first week at altitude, but sleep quantity had still not stabilised at its normal level after 2 weeks. The quantity and quality of sleep obtained by the Bolivians was similar, or greater, on all nights at altitude compared with sea level. The Australians tended to obtain more sleep than the Bolivians at sea level and altitude, but the quality of the Bolivians' sleep tended to be better than that of the Australians at altitude. Exposure to high altitude causes acute and chronic disruption to the sleep of elite athletes who are sea-level natives, but it does not affect the sleep of elite athletes who are high-altitude natives.

  17. A new phase in the production of quality-controlled sea level data

    DEFF Research Database (Denmark)

    Quartly, Graham D.; Legeais, Jean François; Ablain, Michaël

    2017-01-01

    Sea level is an essential climate variable (ECV) that has a direct effect on many people through inundations of coastal areas, and it is also a clear indicator of climate changes due to external forcing factors and internal climate variability. Regional patterns of sea level change inform us...... and predict these phenomena, and thereby alleviate some of the environmental conditions associated with them. All such studies rely on the existence of long-term consistent high-accuracy datasets of sea level. The Climate Change Initiative (CCI) of the European Space Agency was established in 2010 to provide...... improved time series of some ECVs, including sea level, with the purpose of providing such data openly to all to enable the widest possible utilisation of such data. Now in its second phase, the Sea Level CCI project (SL-cci) merges data from nine different altimeter missions in a clear, consistent...

  18. Limits on the adaptability of coastal marshes to rising sea level

    Science.gov (United States)

    Kirwan, Matthew L.; Guntenspergen, Glenn R.; D'Alpaos, Andrea; Morris, James T.; Mudd, Simon M.; Temmerman, Stijn

    2010-01-01

    Assumptions of a static landscape inspire predictions that about half of the world's coastal wetlands will submerge during this century in response to sea-level acceleration. In contrast, we use simulations from five numerical models to quantify the conditions under which ecogeomorphic feedbacks allow coastal wetlands to adapt to projected changes in sea level. In contrast to previous sea-level assessments, we find that non-linear feedbacks among inundation, plant growth, organic matter accretion, and sediment deposition, allow marshes to survive conservative projections of sea-level rise where suspended sediment concentrations are greater than ~20 mg/L. Under scenarios of more rapid sea-level rise (e.g., those that include ice sheet melting), marshes will likely submerge near the end of the 21st century. Our results emphasize that in areas of rapid geomorphic change, predicting the response of ecosystems to climate change requires consideration of the ability of biological processes to modify their physical environment.

  19. IInvestigations of space-time variability of the sea level in the Barents Sea and the White Sea by satellite altimetry data and results of hydrodynamic modelling

    Science.gov (United States)

    Lebedev, S. A.; Zilberstein, O. I.; Popov, S. K.; Tikhonova, O. V.

    2003-04-01

    The problem of retrieving of the sea level anomalies in the Barents and White Seas from satellite can be considered as two different problems. The first one is to calculate the anomalies of sea level along the trek taking into account all amendments including tidal heights. The second one is to obtain of fields of the sea level anomalies on the grid over one cycle of the exact repeat altimetry mission. Experience results show that there is preferable to use the regional tidal model for calculating tidal heights. To construct of the anomalies fields of the sea level during the exact repeat mission (cycle 35 days for ERS-1 and ERS-2), when a density of the coverage of the area of water of the Barents and White Seas by satellite measurements achieves maximum. It is necessary to solve the problem of the error minimum. This error is based by the temporal difference of the measurements over one cycle and by the specific of the hydrodynamic regime of the both seas (tidal, storm surge variations, tidal currents). To solve this problem it is assumed to use the results of the hydrodynamic modeling. The error minimum is preformed by the regression of the model results and satellite measurements. As a version it is considered the possibility of the utilizing of the neuronet obtained by the model results to construct maps of the sea level anomalies. The comparison of the model results and the calculation of the satellite altimetry variability of the sea level of Barents and White Seas shows a good coincidence between them. The satellite altimetry data of ERS-1/2 and TOPEX/POSEIDON of Ocean Altimeter Pathfinder Project (NASA/GSFC) has been used in this study. Results of the regional tidal model computations and three dimensional baroclinic model created in the Hydrometeocenter have been used as well. This study also exploited the atmosphere date of the Project REANALYSIS. The research was undertaken with partial support from the Russian Basic Research Foundation (Project No. 01-07-90106).

  20. Top-level design and local-level paralysis: Local politics in times of political centralisation

    NARCIS (Netherlands)

    Stepan, M.; Ahlers, A.L.; Heilmann, S.; Stepan, M.

    2016-01-01

    China’s leadership under Xi has reinforced the party’s hierarchical command structures, demonstrated through its top-down campaigns, focusing on austerity, anti-corruption efforts and party discipline. It has reinvigorated sanctioning and incentive mechanisms for local cadres, with unknown effects

  1. Principles and reconstruction of the ancient sea levels during the Quaternary

    International Nuclear Information System (INIS)

    Martin, L.; Flexor, J.M.; Suguio, K.

    1986-01-01

    This work focused the multiple aspects related to the ''reconstruction of the ancient sea level during the Quaternary''. The relative sea level, fluctuations are produced by true variations of the level (eustasy) and by changes in the land level (tectonism and isostasy). The changes of the relative levels are reconstructed through several evidence of these fluctuations, which are recognised in time and space. To define their situation in space is necessary to know their present altitude in relation to their original altitude, that is, to determine their position in relation to the sea level during their formation or sedimentation. Their situation in time is determined by measuring the moment of their formation or sedimentation, using for this the dating methods (isotopic, archeological, etc.) When numerous ancient levels could be reconstructed, spread through a considerable time interval, is possible to delineate the sea level fluctuation curve for this period. (C.D.G.) [pt

  2. Tidal and sub-tidal sea level variability at the northern shelf of the Brazilian Northeast Region.

    Science.gov (United States)

    Frota, Felipe F; Truccolo, Eliane C; Schettini, Carlos A F

    2016-09-01

    A characterization of the sea level variability at tidal and sub-tidal frequencies at the northern shore of the Brazilian Northeast shelf for the period 2009-2011 is presented. The sea level data used was obtained from the Permanent Geodetic Tide Network from the Brazilian Institute of Geography and Statistics for the Fortaleza gauge station. Local wind data was also used to assess its effects on the low-frequency sea level variability. The variability of the sea level was investigated by classical harmonic analysis and by morphology assessment over the tidal signal. The low frequencies were obtained by low-pass filtering. The tidal range oscillated with the highest value of 3.3 m during the equinox and the lowest value of 0.7 m during the solstice. Differences between the spring and neap tides were as high as 1 m. A total of 59 tidal constituents were obtained from harmonic analysis, and the regional tide was classified as semi-diurnal pure with a form number of 0.11. An assessment of the monthly variability of the main tidal constituents (M2, S2, N2, O1, and K1) indicated that the main semi-diurnal solar S2 presented the highest variability, ranging from 0.21 to 0.41 m; it was the main element altering the form number through the years. The low frequency sea-level variability is negligible, although there is a persistent signal with an energy peak in the 10-15 day period, and it cannot be explained by the effects of local winds.

  3. Regional Interdependence in Adaptation to Sea Level Rise and Coastal Flooding

    Science.gov (United States)

    Stacey, M. T.; Lubell, M.; Hummel, M.; Wang, R. Q.; Barnard, P.; Erikson, L. H.; Herdman, L.; Pozdnukhov, A.; Sheehan, M.

    2017-12-01

    Projections of sea level rise may differ in the pace of change, but there is clear consensus that coastal communities will be facing more frequent and severe flooding events in the coming century. As communities adapt to future conditions, infrastructure systems will be developed, modified and abandoned, with important consequences for services and resilience. Whether action or inaction is pursued, the decisions made by an individual community regarding a single infrastructure system have implications that extend spatially and temporally due to geographic and infrastructure system interactions. At the same time, there are a number of barriers to collective or coordinated action that inhibit regional solutions. This interplay between local actions and regional responses is one of the great challenges facing decision-makers grappling with both local and regional climate-change adaptation. In this talk, I present case studies of the San Francisco Bay Area that examine how shoreline infrastructure, transporation sytems and decision-making networks interact to define the regional response to local actions and the local response to regional actions. I will characterize the barriers that exist to regional solutions, and characterize three types of interdependence that may motivate decision-makers to overcome those barriers. Using these examples, I will discuss the importance of interdisciplinary analyses that integrate the natural sciences, engineering and the social science to climate change adaptation more generally.

  4. Radioactivity levels in Barents, Petshora, Kara, Laptev and White Seas

    International Nuclear Information System (INIS)

    Rissanen, K.; Matishov, D.; Matishov, G.G.

    1995-01-01

    The samples collected and analysed during joint work between the Finnish Centre for Radiation and Nuclear Safety and the Murmansk Marine Biological Institute cover a rather large area of the arctic in north west Russia. All the analysed sediments, algae, benthic and fish samples, have shown surprisingly low radionuclide concentrations and indicate that the open sea areas are almost uncontaminated. But the most interesting locations with potential risk sources are closed areas. 134 Cs isotope originating from the fallout of the Chernobyl accident was measured only in terrestrial samples collected on the Kola peninsula and around the White Sea. Small amounts of this isotope with only 2 years half-life was also noticed in some sediment samples from White Sea. 134 Cs isotopes was not noticed in any terrestrial sample collected from the coastal area between the Kanin peninsula and the Jenisey river. The very low concentrations of 134 Cs isotope measured in Kara Sea sediment samples were usually in association with an outlet of a river and were obviously transported by river water from the central parts of Russia. The measured low concentrations of the antropogenic radionuclides in the Barents and Petshora Sea originate obviously from the global fallout. The higher White Sea concentrations contain also additional fallout from the Chernobyl accident and probably also some terrestrial runoff. Low concentration of 60 Co isotopes in some sediment, algae and benthic fauna samples, reveals, however, slight fresh contamination, as were concentrations also at the outlet of Jenisey river. The results on well documented sampling locations represent also background data for possible leakage or other accidents. 5 refs., 3 figs, 3 tabs

  5. The Orinoco megadelta as a conservation target in the face of the ongoing and future sea level rise.

    Science.gov (United States)

    Vegas-Vilarrúbia, T; Hernández, E; Rull, Valentí; Rull Vegas, Elisa

    2015-05-15

    Currently, risk assessments related to rising sea levels and the adoption of defensive or adaptive measures to counter these sea level increases are underway for densely populated deltas where economic losses might be important, especially in the developed world. However, many underpopulated deltas harbouring high biological and cultural diversity are also at risk but will most likely continue to be ignored as conservation targets. In this study, we explore the potential effects of erosion, inundation and salinisation on one of the world's comparatively underpopulated megadeltas, the Orinoco Delta. With a 1 m sea level rise expected to occur by 2100, several models predict a moderate erosion of the delta's shorelines, migration or loss of mangroves, general inundation of the delta with an accompanying submersion of wetlands, and an increase in the distance to which sea water intrudes into streams, resulting in harm to the freshwater biota and resources. The Warao people are the indigenous inhabitants of the Orinoco Delta and currently are subject to various socioeconomic stressors. Changes due to sea level rise will occur extremely rapidly and cause abrupt shifts in the Warao's traditional environments and resources, resulting in migrations and abandonment of their ancestral territories. However, evidence indicates that deltaic aggradation/accretion processes at the Orinoco delta due to allochthonous sediment input and vegetation growth could be elevating the surface of the land, keeping pace with the local sea level rise. Other underpopulated and large deltas of the world also may risk immeasurable biodiversity and cultural losses and should not be forgotten as important conservation targets. Copyright © 2015. Published by Elsevier B.V.

  6. Future hydrological alterations in the Mekong Delta under the impact of water resources development, land subsidence and sea level rise

    Directory of Open Access Journals (Sweden)

    Thanh Duc Dang

    2018-02-01

    New hydrological insights for the region: Depending on hydrological characteristics of each region (river-dominated, transitional or tidal, the influence of each potential driver may vary. The operation of proposed hydropower dams would change river-dominated upper floodplain’s water levels by 26 to 70% and −0.8 to −5.9% in the dry and wet season respectively, but the impact diminishes throughout the floodplains. In the wet season, the upper Vietnamese Delta changes from a transitional stage to a river-dominated stage, and localized water infrastructure development in the upper delta has the greatest effect on water levels in the region. Land subsidence combined with sea level rise could have the greatest future influence on flooding in the delta if current rates are extrapolated. Sustainable water management strategies are thus necessary to mitigate changes in the floodplains and delta and increase resilience to sea level rise and land subsidence.

  7. Relationship between sea level and climate forcing by CO2 on geological timescales.

    Science.gov (United States)

    Foster, Gavin L; Rohling, Eelco J

    2013-01-22

    On 10(3)- to 10(6)-year timescales, global sea level is determined largely by the volume of ice stored on land, which in turn largely reflects the thermal state of the Earth system. Here we use observations from five well-studied time slices covering the last 40 My to identify a well-defined and clearly sigmoidal relationship between atmospheric CO(2) and sea level on geological (near-equilibrium) timescales. This strongly supports the dominant role of CO(2) in determining Earth's climate on these timescales and suggests that other variables that influence long-term global climate (e.g., topography, ocean circulation) play a secondary role. The relationship between CO(2) and sea level we describe portrays the "likely" (68% probability) long-term sea-level response after Earth system adjustment over many centuries. Because it appears largely independent of other boundary condition changes, it also may provide useful long-range predictions of future sea level. For instance, with CO(2) stabilized at 400-450 ppm (as required for the frequently quoted "acceptable warming" of 2 °C), or even at AD 2011 levels of 392 ppm, we infer a likely (68% confidence) long-term sea-level rise of more than 9 m above the present. Therefore, our results imply that to avoid significantly elevated sea level in the long term, atmospheric CO(2) should be reduced to levels similar to those of preindustrial times.

  8. Southern Dobrogea coastal potable water sources and Upper Quaternary Black Sea level changes

    Science.gov (United States)

    Caraivan, Glicherie; Stefanescu, Diana

    2013-04-01

    Southern Dobrogea is a typical geologic platform unit, placed in the south-eastern part of Romania, with a Pre-Cambrian crystalline basement and a Paleozoic - Quaternary sedimentary cover. It is bordered to the north by the Capidava - Ovidiu fault and by the Black Sea to the east. A regional WNW - ESE and NNE - SSW fault system divides the Southern Dobrogea structure in several tectonic blocks. Four drinking water sources have been identified: surface water, phreatic water, medium depth Sarmatian aquifer, and deep Upper Jurassic - Lower Cretaceous aquifer. Surface water sources are represented by several springs emerged from the base of the loess cliff, and a few small rivers, barred by coastal beaches. The phreatic aquifer develops at the base of the loess deposits, on the impervious red clay, overlapping the Sarmatian limestones. The medium depth aquifer is located in the altered and karstified Sarmatian limestones, and discharges into the Black Sea. The Sarmatian aquifer is unconfined where covered by silty loess deposits, and locally confined, where capped by clayey loess deposits. The aquifer is supplied from the Pre-Balkan Plateau. The Deep Upper Jurassic - Lower Cretaceous aquifer, located in the limestone and dolomite deposits, is generally confined and affected by the regional WNW - ESE and NNE - SSW fault system. In the south-eastern Dobrogea, the deep aquifer complex is separated from the Sarmatian aquifer by a Senonian aquitard (chalk and marls). The natural boundary of the Upper Jurassic - Lower Cretaceous aquifer is the Capidava - Ovidiu Fault. The piezometric heads show that the Upper Jurassic - Lower Cretaceous aquifer is supplied from the Bulgarian territory, where the Upper Jurassic deposits crop out. The aquifer discharges into the Black Sea to the east and into Lake Siutghiol to the northeast. The cyclic Upper Quaternary climate changes induced drastic remodeling of the Black Sea level and the corresponding shorelines. During the Last Glacial

  9. Recent Changes in Land Water Storage and Its Contribution to Sea Level Variations

    Science.gov (United States)

    Wada, Yoshihide; Reager, John T.; Chao, Benjamin F.; Wang, Jida; Lo, Min-Hui; Song, Chunqiao; Li, Yuwen; Gardner, Alex S.

    2016-01-01

    Sea level rise is generally attributed to increased ocean heat content and increased rates glacier and ice melt. However, human transformations of Earth's surface have impacted water exchange between land, atmosphere, and ocean, ultimately affecting global sea level variations. Impoundment of water in reservoirs and artificial lakes has reduced the outflow of water to the sea, while river runoff has increased due to groundwater mining, wetland and endorheic lake storage losses, and deforestation. In addition, climate-driven changes in land water stores can have a large impact on global sea level variations over decadal timescales. Here, we review each component of negative and positive land water contribution separately in order to highlight and understand recent changes in land water contribution to sea level variations.

  10. The Science-Policy Link: Stakeholder Reactions to the Uncertainties of Future Sea Level Rise

    Science.gov (United States)

    Plag, H.; Bye, B.

    2011-12-01

    Policy makers and stakeholders in the coastal zone are equally challenged by the risk of an anticipated rise of coastal Local Sea Level (LSL) as a consequence of future global warming. Many low-lying and often densely populated coastal areas are under risk of increased inundation. More than 40% of the global population is living in or near the coastal zone and this fraction is steadily increasing. A rise in LSL will increase the vulnerability of coastal infrastructure and population dramatically, with potentially devastating consequences for the global economy, society, and environment. Policy makers are faced with a trade-off between imposing today the often very high costs of coastal protection and adaptation upon national economies and leaving the costs of potential major disasters to future generations. They are in need of actionable information that provides guidance for the development of coastal zones resilient to future sea level changes. Part of this actionable information comes from risk and vulnerability assessments, which require information on future LSL changes as input. In most cases, a deterministic approach has been applied based on predictions of the plausible range of future LSL trajectories as input. However, there is little consensus in the scientific community on how these trajectories should be determined, and what the boundaries of the plausible range are. Over the last few years, many publications in Science, Nature and other peer-reviewed scientific journals have revealed a broad range of possible futures and significant epistemic uncertainties and gaps concerning LSL changes. Based on the somewhat diffuse science input, policy and decision makers have made rather different choices for mitigation and adaptation in cases such as Venice, The Netherlands, New York City, and the San Francisco Bay area. Replacing the deterministic, prediction-based approach with a statistical one that fully accounts for the uncertainties and epistemic gaps

  11. Sensitivity analysis of hydrogeological parameters affecting groundwater storage change caused by sea level rise

    Science.gov (United States)

    Shin, J.; Kim, K.-H.; Lee, K.-K.

    2012-04-01

    Sea level rise, which is one of the representative phenomena of climate changes caused by global warming, can affect groundwater system. The rising trend of the sea level caused by the global warming is reported to be about 3 mm/year for the most recent 10 year average (IPCC, 2007). The rate of sea level rise around the Korean peninsula is reported to be 2.30±2.22 mm/yr during the 1960-1999 period (Cho, 2002) and 2.16±1.77 mm/yr (Kim et al., 2009) during the 1968-2007 period. Both of these rates are faster than the 1.8±0.5 mm/yr global average for the similar 1961-2003 period (IPCC, 2007). In this study, we analyzed changes in the groundwater environment affected by the sea level rise by using an analytical methodology. We tried to find the most effective parameters of groundwater amount change in order to estimate the change in fresh water amount in coastal groundwater. A hypothetical island model of a cylindrical shape in considered. The groundwater storage change is bi-directional as the sea level rises according to the natural and hydrogeological conditions. Analysis of the computation results shows that topographic slope and hydraulic conductivity are the most sensitive factors. The contributions of the groundwater recharge rate and the thickness of aquifer below sea level are relatively less effective. In the island with steep seashore slopes larger than 1~2 degrees or so, the storage amount of fresh water in a coastal area increases as sea level rises. On the other hand, when sea level drops, the storage amount decreases. This is because the groundwater level also rises with the rising sea level in steep seashores. For relatively flat seashores, where the slope is smaller than around 1-2 degrees, the storage amount of coastal fresh water decreases when the sea level rises because the area flooded by the rising sea water is increased. The volume of aquifer fresh water in this circumstance is greatly reduced in proportion to the flooded area with the sea

  12. An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative

    Science.gov (United States)

    Legeais, Jean-François; Ablain, Michaël; Zawadzki, Lionel; Zuo, Hao; Johannessen, Johnny A.; Scharffenberg, Martin G.; Fenoglio-Marc, Luciana; Joana Fernandes, M.; Baltazar Andersen, Ole; Rudenko, Sergei; Cipollini, Paolo; Quartly, Graham D.; Passaro, Marcello; Cazenave, Anny; Benveniste, Jérôme

    2018-02-01

    Sea level is a very sensitive index of climate change since it integrates the impacts of ocean warming and ice mass loss from glaciers and the ice sheets. Sea level has been listed as an essential climate variable (ECV) by the Global Climate Observing System (GCOS). During the past 25 years, the sea level ECV has been measured from space by different altimetry missions that have provided global and regional observations of sea level variations. As part of the Climate Change Initiative (CCI) program of the European Space Agency (ESA) (established in 2010), the Sea Level project (SL_cci) aimed to provide an accurate and homogeneous long-term satellite-based sea level record. At the end of the first phase of the project (2010-2013), an initial version (v1.1) of the sea level ECV was made available to users (Ablain et al., 2015). During the second phase of the project (2014-2017), improved altimeter standards were selected to produce new sea level products (called SL_cci v2.0) based on nine altimeter missions for the period 1993-2015 (https://doi.org/10.5270/esa-sea_level_cci-1993_2015-v_2.0-201612; Legeais and the ESA SL_cci team, 2016c). Corresponding orbit solutions, geophysical corrections and altimeter standards used in this v2.0 dataset are described in detail in Quartly et al. (2017). The present paper focuses on the description of the SL_cci v2.0 ECV and associated uncertainty and discusses how it has been validated. Various approaches have been used for the quality assessment such as internal validation, comparisons with sea level records from other groups and with in situ measurements, sea level budget closure analyses and comparisons with model outputs. Compared with the previous version of the sea level ECV, we show that use of improved geophysical corrections, careful bias reduction between missions and inclusion of new altimeter missions lead to improved sea level products with reduced uncertainties on different spatial and temporal scales. However, there

  13. Thresholds of sea-level rise rate and sea-level acceleration rate in a vulnerable coastal wetland

    Science.gov (United States)

    Wu, W.; Biber, P.; Bethel, M.

    2017-12-01

    Feedback among inundation, sediment trapping, and vegetation productivity help maintain coastal wetlands facing sea-level rise (SLR). However, when the SLR rate exceeds a threshold, coastal wetlands can collapse. Understanding the threshold help address the key challenge in ecology - nonlinear response of ecosystems to environmental change, and promote communication between ecologists and policy makers. We studied the threshold of SLR rate and developed a new threshold of SLR acceleration rate on sustainability of coastal wetlands as SLR is likely to accelerate due to the enhanced anthropogenic forces. We developed a mechanistic model to simulate wetland change and derived the SLR thresholds for Grand Bay, MS, a micro-tidal estuary with limited upland freshwater and sediment input in the northern Gulf of Mexico. The new SLR acceleration rate threshold complements the threshold of SLR rate and can help explain the temporal lag before the rapid decline of wetland area becomes evident after the SLR rate threshold is exceeded. Deriving these two thresholds depends on the temporal scale, the interaction of SLR with other environmental factors, and landscape metrics, which have not been fully accounted for before this study. The derived SLR rate thresholds range from 7.3 mm/yr to 11.9 mm/yr. The thresholds of SLR acceleration rate are 3.02×10-4 m/yr2 and 9.62×10-5 m/yr2 for 2050 and 2100 respectively. Based on the thresholds developed, predicted SLR that will adversely impact the coastal wetlands in Grand Bay by 2100 will fall within the likely range of SLR under a high warming scenario (RCP8.5), and beyond the very likely range under a low warming scenario (RCP2.6 or 3), highlighting the need to avoid the high warming scenario in the future if these marshes are to be preserved.

  14. Atmospheric forcing of decadal Baltic Sea level variability in the last 200 years. A statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huenicke, B. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Kuestenforschung

    2008-11-06

    This study aims at the estimation of the impact of different atmospheric factors on the past sealevel variations (up to 200 years) in the Baltic Sea by statistically analysing the relationship between Baltic Sea level records and observational and proxy-based reconstructed climatic data sets. The focus lies on the identification and possible quantification of the contribution of sealevel pressure (wind), air-temperature and precipitation to the low-frequency (decadal and multi-decadal) variability of Baltic Sea level. It is known that the wind forcing is the main factor explaining average Baltic Sea level variability at inter-annual to decadal timescales, especially in wintertime. In this thesis it is statistically estimated to what extent other regional climate factors contribute to the spatially heterogeneous Baltic Sea level variations around the isostatic trend at multi-decadal timescales. Although the statistical analysis cannot be completely conclusive, as the potential climate drivers are all statistically interrelated to some degree, the results indicate that precipitation should be taken into account as an explanatory variable for sea-level variations. On the one hand it has been detected that the amplitude of the annual cycle of Baltic Sea level has increased throughout the 20th century and precipitation seems to be the only factor among those analysed (wind through SLP field, barometric effect, temperature and precipitation) that can account for this evolution. On the other hand, precipitation increases the ability to hindcast inter-annual variations of sea level in some regions and seasons, especially in the Southern Baltic in summertime. The mechanism by which precipitation exerts its influence on Baltic Sea level is not ascertained in this statistical analysis due to the lack of long salinity time series. This result, however, represents a working hypothesis that can be confirmed or disproved by long simulations of the Baltic Sea system - ocean

  15. Lithostratigraphy, depositional history and sea level changes of the Cauvery Basin, southern India

    Directory of Open Access Journals (Sweden)

    Muthuvairvasamy Ramkumar

    2003-01-01

    Full Text Available The sedimentary sequence exposed in the erstwhile Tiruchirapalli district hosts a more or less complete geological record of the Upper Cretaceous-Tertiary period. Systematic field mapping, collation of data on the micro-meso scale lithology, sedimentary structures, petrography, faunal assemblage and facies relationships of these rocks, in the light of modern stratigraphic concepts, helped to enumerate the lithostratigraphic setup and depositional history of the basin. Spatial and temporal variations of the lithologies and revised stratigraphic units are presented in this paper. Many high frequency sea level cycles (presumably fourth or higher order which stack up to form third order sea level cycles (six in number, which in turn form part of second order cycles (two in number, including seven eustatic sea level peaks, have been recorded in this basin. Trend analysis of sea level curves indicates a gradual increase of the sea level from Barremian to Coniacian and a gradual decrease from Coniacian to Danian. Such lasting sea level trends had their influence on the sedimentation pattern and facies association. It is inferred that depositional bathymetry was maintained at a shallow-moderate level, primarily influenced by a lack of major subsidence during the depositional history of this basin. The study also revealed a prevalent simple basin filling process and dominant control by sea level changes, rather than tectonic movements over the depositional regime.

  16. Coastal Hazards Maps: Actionable Information for Communities Facing Sea-Level Rise (Invited)

    Science.gov (United States)

    Gibeaut, J. C.; Barraza, E.

    2010-12-01

    Barrier islands along the U.S. Gulf coast remain under increasing pressure from development. This development and redevelopment is occurring despite recent hurricanes, ongoing erosion, and sea-level rise. To lessen the impacts of these hazards, local governments need information in a form that is useful for informing the public, making policy, and enforcing development rules. We recently completed the Galveston Island Geohazards Map for the city of Galveston, Texas and are currently developing maps for the Mustang and South Padre Island communities. The maps show areas that vary in their susceptibility to, and function for, mitigating the effects of geological processes, including sea-level rise, land subsidence, erosion and storm-surge flooding and washover. The current wetlands, beaches and dunes are mapped as having the highest geohazard potential both in terms of their exposure to hazardous conditions and their mitigating effects of those hazards for the rest of the island. These existing “critical environments” are generally protected under existing regulations. Importantly, however, the mapping recognizes that sea-level rise and shoreline retreat are changing the island; therefore, 60-year model projections of the effects of these changes are incorporated into the map. The areas that we project will become wetlands, beaches and dunes in the next 60 years are not protected. These areas are the most difficult to deal with from a policy point of view, yet we must address what happens there if real progress is to be made in how we live with sea-level rise. The geohazards maps draw on decades of geological knowledge of how barrier islands behave and put it in a form that is intuitive to the public and directly useful to planners. Some of the “messages” in the map include: leave salt marshes alone and give them room to migrate inland as sea level rises; set back and move development away from the shoreline to provide space for beaches and protective dunes

  17. Sea Level Change and Coastal Climate Services: The Way Forward

    NARCIS (Netherlands)

    le Cozannet, G.; Nicholls, R.J.; Hinkel, J.; Sweet, W.V.; McInnes, K.L.; Van de Wal, R.S.E.; Slangen, A.B.A.; Lowe, J.A.; White, K.D.

    2017-01-01

    For many climate change impacts such as drought and heat waves, global and nationalframeworks for climate services are providing ever more critical support to adaptation activities.Coastal zones are especially in need of climate services for adaptation, as they are increasinglythreatened by sea

  18. Seasonal sea level variability and anomalies in the Singapore Strait

    Digital Repository Service at National Institute of Oceanography (India)

    Tkalich, P.; Vethamony, P.; Babu, M.T.; Pokratath, P.

    of a tropical cyclone near the equator (Chang, 2003). Vamei developed on December 26 at 1.4 N in the South China Sea, and made landfall approximately 60km northeast of Singapore in the southeastern portion of the Malaysian state of Johor (Fig. 6a...

  19. Sea level change and coastal climate services : The way forward

    NARCIS (Netherlands)

    Le Cozannet, Gonéri; Nicholls, Robert J.; Hinkel, Jochen; Sweet, William V.; McInnes, Kathleen L.; Van de Wal, Roderik S.W.; Slangen, Aimée B.A.; Lowe, Jason A.; White, Kathleen D.

    2017-01-01

    For many climate change impacts such as drought and heat waves, global and national frameworks for climate services are providing ever more critical support to adaptation activities. Coastal zones are especially in need of climate services for adaptation, as they are increasingly threatened by sea

  20. Level and origin of Iodine-129 in the Baltic Sea

    Czech Academy of Sciences Publication Activity Database

    Hou, XL.; Dahlgaard, H.; Nielsen, SP.; Kučera, Jan

    2002-01-01

    Roč. 61, č. 3 (2002), s. 331-343 ISSN 0265-931X R&D Projects: GA AV ČR KSK4055109 Keywords : lodine-129 * Baltic sea * neutron activation analysis * seawater Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 0.674, year: 2002

  1. Assessment of the impact of sea-level rise due to climate change on coastal groundwater discharge.

    Science.gov (United States)

    Masciopinto, Costantino; Liso, Isabella Serena

    2016-11-01

    An assessment of sea intrusion into coastal aquifers as a consequence of local sea-level rise (LSLR) due to climate change was carried out at Murgia and Salento in southern Italy. The interpolation of sea-level measurements at three tide-gauge stations was performed during the period of 2000 to 2014. The best fit of measurements shows an increasing rate of LSLR ranging from 4.4mm/y to 8.8mm/y, which will result in a maximum LSLR of approximately 2m during the 22nd century. The local rate of sea-level rise matches recent 21st and 22nd century projections of mean global sea-level rise determined by other researchers, which include increased melting rates of the Greenland and Antarctic ice sheets, the effect of ocean thermal expansion, the melting of glaciers and ice caps, and changes in the quantity of stored land water. Subsequently, Ghyben-Herzberg's equation for the freshwater/saltwater interface was rewritten in order to determine the decrease in groundwater discharge due to the maximum LSLR. Groundwater flow simulations and ArcGIS elaborations of digital elevation models of the coast provided input data for the Ghyben-Herzberg calculation under the assumption of head-controlled systems. The progression of seawater intrusion due to LSLR suggests an impressive depletion of available groundwater discharge during the 22nd century, perhaps as much as 16.1% of current groundwater pumping for potable water in Salento. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Absolute sea levels and isostatic changes of the eastern North Sea to central Baltic region during the last 900 years

    DEFF Research Database (Denmark)

    Hansen, Jens Morten; Aagaard, Troels; Binderup, Merete

    2012-01-01

    that ice-cap growth can be faster than ice-cap melting. By comparison with 29 long-term tide gauge measurements of the region we show that the isostatic implications of the sea-level curve are in nearly perfect agreement with Peltier's global isostatic VM2 model (applied by IPCC and PSMSL) and yield a 3...

  3. Doubling of coastal flooding frequency within decades due to sea-level rise

    Science.gov (United States)

    Vitousek, Sean; Barnard, Patrick L.; Fletcher, Charles H.; Frazer, Neil; Erikson, Li; Storlazzi, Curt D.

    2017-01-01

    Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

  4. Doubling of coastal flooding frequency within decades due to sea-level rise.

    Science.gov (United States)

    Vitousek, Sean; Barnard, Patrick L; Fletcher, Charles H; Frazer, Neil; Erikson, Li; Storlazzi, Curt D

    2017-05-18

    Global climate change drives sea-level rise, increasing the frequency of coastal flooding. In most coastal regions, the amount of sea-level rise occurring over years to decades is significantly smaller than normal ocean-level fluctuations caused by tides, waves, and storm surge. However, even gradual sea-level rise can rapidly increase the frequency and severity of coastal flooding. So far, global-scale estimates of increased coastal flooding due to sea-level rise have not considered elevated water levels due to waves, and thus underestimate the potential impact. Here we use extreme value theory to combine sea-level projections with wave, tide, and storm surge models to estimate increases in coastal flooding on a continuous global scale. We find that regions with limited water-level variability, i.e., short-tailed flood-level distributions, located mainly in the Tropics, will experience the largest increases in flooding frequency. The 10 to 20 cm of sea-level rise expected no later than 2050 will more than double the frequency of extreme water-level events in the Tropics, impairing the developing economies of equatorial coastal cities and the habitability of low-lying Pacific island nations.

  5. Localized-to-extended-states transition below the Fermi level

    Science.gov (United States)

    Tito, M. A.; Pusep, Yu. A.

    2018-05-01

    Time-resolved photoluminescence is employed to examine a transition from localized to extended electron states below the Fermi level in multiple narrow quantum well GaAs/AlGaAs heterostructures, where disorder was generated by interface roughness. Such a transition resembles the metal-insulator transition profoundly investigated by electric transport measurements. An important distinction distinguishes the localized-to-extended-states transition studied here: it takes place below the Fermi level in an electron system with a constant concentration, which implies unchanging Coulomb correlations. Moreover, for such a localized-to-extended-states transition the temperature is shown to be irrelevant. In the insulating regime the magnetic field was found to cause an additional momentum relaxation which considerably enhanced the recombination rate. Thus, we propose a method to explore the evolution of the localized electron states in a system with a fixed disorder and Coulomb interaction.

  6. Cities and Sea Level Rise: A Roadmap for Flood Hazard Adaptation

    Science.gov (United States)

    Horn, Diane; Cousins, Ann

    2016-04-01

    Coastal cities will face a range of increasingly severe challenges as sea level rises, and adaptation to future flood risk will require more than structural defences. Many cities will not be able to rely solely on engineering structures for protection and will need to develop a suite of policy responses to increase their resilience to impacts of rising sea level. The tools to promote flood risk adaptation are already within the capacity of most cities, with an assortment of policy tools available to address other land-use problems which can be refashioned and used to adapt to sea level rise. This study reviews approaches for urban adaptation through detailed analyses of case studies of cities which have developed flood adaptation strategies that combine structural defences with innovative approaches to living with flood risk. The aim of the overall project is to produce a 'roadmap' to guide practitioners through the process of analysing coastal flood risk in urban areas. Methodologies and tools to estimate vulnerability to coastal flooding, damages suffered, and the assessment of flood defences and adaptation measures are complemented with a discussion on the essential impact that local policy has on the treatment of coastal flooding and the constraints and opportunities that result from the specific country or locality characteristics in relation to economic, political, social and environmental priorities, which are likely to dictate the approach to coastal flooding and the actions proposed. Case studies of adaptation strategies used by Rotterdam, Bristol, Ho Chi Minh City and Norfolk, Virginia, are used to draw out a range of good practice elements that promote effective adaptation to sea level rise. These can be grouped into risk reduction, governance issues, and insurance, and can be used to provide examples of how other cities could adopt and implement flood adaptation strategies from a relatively limited starting position. Most cities will neither be able to

  7. Present-day sea level rise: a synthesis; Hausse actuelle du niveau de la mer: synthese

    Energy Technology Data Exchange (ETDEWEB)

    Cazenave, A.; Llovel, W. [Laboratoire d' Etudes en Geophysique et Oceanographie Spatiales (LEGOS), Observatoire Midi-Pyrenees, 31 - Toulouse (France); Lombard, A. [CNES, 31 - Toulouse (France)

    2008-11-15

    Measuring sea level change and understanding its causes have improved considerably in the recent years, essentially because new in situ and remote sensing data sets have become available. Here we report on the current knowledge of present-day sea level change. We briefly present observational results on sea level change from satellite altimetry since 1993 and tide gauges for the past century. We next discuss recent progress made in quantifying the processes causing sea level change on time scales ranging from years to decades, i.e., thermal expansion, land ice mass loss and land water storage change. For the 1993-2003 decade, the sum of climate-related contributions agree well (within the error bars) with the altimetry-based sea level, half of the observed rate of rise being due to ocean thermal expansion, land ice plus land waters explaining the other half. Since about 2003, thermal expansion increase has stopped, whereas the sea level continues to rise, although at a reduced rate compared to the previous decade (2.5 mm/yr versus 3.1 mm/yr). Recent increases in glacier melting and ice mass loss from the ice sheets appear able to account alone for the rise in sea level reported over the last five years. (authors)

  8. Uncertainties in Steric Sea Level Change Estimation During the Satellite Altimeter Era: Concepts and Practices

    Science.gov (United States)

    MacIntosh, C. R.; Merchant, C. J.; von Schuckmann, K.

    2017-01-01

    This article presents a review of current practice in estimating steric sea level change, focussed on the treatment of uncertainty. Steric sea level change is the contribution to the change in sea level arising from the dependence of density on temperature and salinity. It is a significant component of sea level rise and a reflection of changing ocean heat content. However, tracking these steric changes still remains a significant challenge for the scientific community. We review the importance of understanding the uncertainty in estimates of steric sea level change. Relevant concepts of uncertainty are discussed and illustrated with the example of observational uncertainty propagation from a single profile of temperature and salinity measurements to steric height. We summarise and discuss the recent literature on methodologies and techniques used to estimate steric sea level in the context of the treatment of uncertainty. Our conclusions are that progress in quantifying steric sea level uncertainty will benefit from: greater clarity and transparency in published discussions of uncertainty, including exploitation of international standards for quantifying and expressing uncertainty in measurement; and the development of community "recipes" for quantifying the error covariances in observations and from sparse sampling and for estimating and propagating uncertainty across spatio-temporal scales.

  9. Late Holocene higher sea level and its radiocarbon dates in Okierabu-jima, Ryukyus

    International Nuclear Information System (INIS)

    Koba, Motoharu; Omoto, Kunio; Takahashi, Tatsuo.

    1980-01-01

    Okierabu-jima of the Ryukyu Islands, which is a poly-terraced Pleistocene raised coral reef island, doesn't have a Holocene raised coral reef, but coastal erosional features showing higher sea levels in Holocene. The authors obtained some data indicating the period of one of the Holocene higher sea levels. All radiocarbon dates concerning Okierabu-jima's Holocene sea-level changes are plotted on the date-height coordinates. The paleo sea level between 5000 and 2000 y. B. P. lies above the broken line drawn from 6 m below to 2.18 m above the present sea level. The period of the highest sea level in Holocene seems to be about 3000 to 2000 y. B. P. in this island. Its height is presumably 2.4 m a. s. l. derived on an average from heights of stacks and coastal benches in the almost all coasts of the island (Koba, 1974). Beach rocks were already formed at the landward extremity of the reef flat corresponding to the almost present sea level about 1300 y. B. P. (author)

  10. Observation-Driven Estimation of the Spatial Variability of 20th Century Sea Level Rise

    Science.gov (United States)

    Hamlington, B. D.; Burgos, A.; Thompson, P. R.; Landerer, F. W.; Piecuch, C. G.; Adhikari, S.; Caron, L.; Reager, J. T.; Ivins, E. R.

    2018-03-01

    Over the past two decades, sea level measurements made by satellites have given clear indications of both global and regional sea level rise. Numerous studies have sought to leverage the modern satellite record and available historic sea level data provided by tide gauges to estimate past sea level rise, leading to several estimates for the 20th century trend in global mean sea level in the range between 1 and 2 mm/yr. On regional scales, few attempts have been made to estimate trends over the same time period. This is due largely to the inhomogeneity and quality of the tide gauge network through the 20th century, which render commonly used reconstruction techniques inadequate. Here, a new approach is adopted, integrating data from a select set of tide gauges with prior estimates of spatial structure based on historical sea level forcing information from the major contributing processes over the past century. The resulting map of 20th century regional sea level rise is optimized to agree with the tide gauge-measured trends, and provides an indication of the likely contributions of different sources to regional patterns. Of equal importance, this study demonstrates the sensitivities of this regional trend map to current knowledge and uncertainty of the contributing processes.

  11. Committed sea-level rise under the Paris Agreement and the legacy of delayed mitigation action.

    Science.gov (United States)

    Mengel, Matthias; Nauels, Alexander; Rogelj, Joeri; Schleussner, Carl-Friedrich

    2018-02-20

    Sea-level rise is a major consequence of climate change that will continue long after emissions of greenhouse gases have stopped. The 2015 Paris Agreement aims at reducing climate-related risks by reducing greenhouse gas emissions to net zero and limiting global-mean temperature increase. Here we quantify the effect of these constraints on global sea-level rise until 2300, including Antarctic ice-sheet instabilities. We estimate median sea-level rise between 0.7 and 1.2 m, if net-zero greenhouse gas emissions are sustained until 2300, varying with the pathway of emissions during this century. Temperature stabilization below 2 °C is insufficient to hold median sea-level rise until 2300 below 1.5 m. We find that each 5-year delay in near-term peaking of CO 2 emissions increases median year 2300 sea-level rise estimates by ca. 0.2 m, and extreme sea-level rise estimates at the 95th percentile by up to 1 m. Our results underline the importance of near-term mitigation action for limiting long-term sea-level rise risks.

  12. Coastline Mapping and Cultural Review to Predict Sea Level Rise Impact on Hawaiian Archeological Sites

    Science.gov (United States)

    Clinton, J.

    2017-12-01

    Much of Hawaii's history is recorded in archeological sites. Researchers and cultural practitioners have been studying and reconstructing significant archeological sites for generations. Climate change, and more specifically, sea level rise may threaten these sites. Our research records current sea levels and then projects possible consequences to these cultural monuments due to sea level rise. In this mixed methods study, research scientists, cultural practitioners, and secondary students use plane-table mapping techniques to create maps of coastlines and historic sites. Students compare historical records to these maps, analyze current sea level rise trends, and calculate future sea levels. They also gather data through interviews with community experts and kupuna (elders). If climate change continues at projected rates, some historic sites will be in danger of negative impact due to sea level rise. Knowing projected sea levels at specific sites allows for preventative action and contributes to raised awareness of the impacts of climate change to the Hawaiian Islands. Students will share results with the community and governmental agencies in hopes of inspiring action to minimize climate change. It will take collaboration between scientists and cultural communities to inspire future action on climate change.

  13. Mapping coastal sea level at high resolution with radar interferometry: the SWOT Mission

    Science.gov (United States)

    Fu, L. L.; Chao, Y.; Laignel, B.; Turki, I., Sr.

    2017-12-01

    The spatial resolution of the present constellation of radar altimeters in mapping two-dimensional sea surface height (SSH) variability is approaching 100 km (in wavelength). At scales shorter than 100 km, the eddies and fronts are responsible for the stirring and mixing of the ocean, especially important in the various coastal processes. A mission currently in development will make high-resolution measurement of the height of water over the ocean as well as on land. It is called Surface Water and Ocean Topography (SWOT), which is a joint mission of US NASA and French CNES, with contributions from Canada and UK. SWOT will carry a pair of interferometry radars and make 2-dimensional SSH measurements over a swath of 120 km with a nadir gap of 20 km in a 21-day repeat orbit. The synthetic aperture radar of SWOT will make SSH measurement at extremely high resolution of 10-70 m. SWOT will also carry a nadir looking conventional altimeter and make 1-dimensional SSH measurements along the nadir gap. The temporal sampling varies from 2 repeats per 21 days at the equator to more than 4 repeats at mid latitudes and more than 6 at high latitudes. This new mission will allow a continuum of fine-scale observations from the open ocean to the coasts, estuaries and rivers, allowing us to investigate a number of scientific and technical questions in the coastal and estuarine domain to assess the coastal impacts of regional sea level change, such as the interaction of sea level with river flow, estuary inundation, storm surge, coastal wetlands, salt water intrusion, etc. As examples, we will illustrate the potential impact of SWOT to the studies of the San Francisco Bay Delta, and the Seine River estuary, etc. Preliminary results suggest that the SWOT Mission will provide fundamental data to map the spatial variability of water surface elevations under different hydrodynamic conditions and at different scales (local, regional and global) to improve our knowledge of the complex

  14. Estimation of sea level variations with GPS/GLONASS-reflectometry technique

    Science.gov (United States)

    Padokhin, A. M.; Kurbatov, G. A.; Andreeva, E. S.; Nesterov, I. A.; Nazarenko, M. O.; Berbeneva, N. A.; Karlysheva, A. V.

    2017-11-01

    In the present paper we study GNSS - reflectometry methods for estimation of sea level variations using a single GNSSreceiver, which are based on the multipath propagation effects caused by the reflection of navigational signals from the sea surface. Such multipath propagation results in the appearance of the interference pattern in the Signal-to-Noise Ratio (SNR) of GNSS signals at small satellite elevation angles, which parameters are determined by the wavelength of the navigational signal and height of the antenna phase center above the reflecting sea surface. In current work we used GPS and GLONASS signals and measurements at two working frequencies of both systems to study sea level variations which almost doubles the amount of observations compared to GPS-only tide gauge. For UNAVCO sc02 station and collocated Friday Harbor NOAA tide gauge we show good agreement between GNSS-reflectometry and traditional mareograph sea level data.

  15. Sea level measured by tide gauges from global oceans as part of the Joint Archive for Sea Level (JASL) from 1846-01-01 to 2015-07-31

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection contains the complete holdings of the Joint Archive for Sea Level (JASL) for sea level data that have been quality controlled, assessed, and...

  16. Sea Level History in 3D: Early results of an ultra-high resolution MCS survey across IODP Expedition 313 drillsites

    Science.gov (United States)

    Mountain, G. S.; Kucuk, H. M.; Nedimovic, M. R.; Austin, J. A., Jr.; Fulthorpe, C.; Newton, A.; Baldwin, K.; Johnson, C.; Stanley, J. N.; Bhatnagar, T.

    2015-12-01

    Although globally averaged sea level is rising at roughly 3 mm/yr (and is accelerating), rates of local sea-level change measured at coastlines may differ from this number by a factor of two or more; at some locations, sea level may even be falling. This is due to local processes that can match or even reverse the global trend, making it clear that reliable predictions of future impacts of sea-level rise require a firm understanding of processes at the local level. The history of local sea-level change and shoreline response is contained in the geologic record of shallow-water sediments. We report on a continuing study of sea-level history in sediments at the New Jersey continental margin, where compaction and glacial isostatic adjustment are currently adding 2 mm/yr to the globally averaged rise. We collected 570 sq km of ultra-high resolution 3D MCS data aboard the R/V Langseth in June-July 2015; innovative recording and preliminary results are described by Nedimovic et al. in this same session. The goal was to provide regional context to coring and logging at IODP Exp 313 sites 27-29 that were drilled 750 m into the New Jersey shelf in 2009. These sites recovered a nearly continuous record of post-Eocene sediments from non-marine soils, estuaries, shoreface, delta front, pro-delta and open marine settings. Existing seismic data are good but are 2D high-resolution profiles at line spacings too wide to enable mapping of key nearshore features. The Langseth 3D survey used shallow towing of a tuned air gun array to preserve high frequencies, and twenty-four 50-m PCables each 12.5 apart provided 6.25 x 3.125 m common-midpoint bins along seventy-seven 50-km sail lines. With this especially dense spatial resolution of a pre-stack time migrated volume we expect to map rivers, incised valleys, barrier islands, inlets and bays, pro-delta clinoforms, tidal deltas, sequence boundaries, debris flow aprons, and more. Seismic attributes linked to sedimentary facies and

  17. Modeling the Effects of Sea-Level Rise on Groundwater Levels in Coastal New Hampshire

    Science.gov (United States)

    Jacobs, J. M.; Knott, J. F.; Daniel, J.; Kirshen, P. H.

    2017-12-01

    Coastal communities with high population density and low topography are vulnerable from sea-level rise (SLR) caused by climate change. Groundwater in coastal communities will rise with sea level impacting water quality, the structural integrity of infrastructure, and natural ecosystem health. SLR-induced groundwater rise has been studied in areas of high aquifer transmissivity and in low-lying areas immediately along the coast. In this regional study, we investigate SLR-induced groundwater rise in a coastal area characterized by shallow unconsolidated deposits overlying fractured bedrock, typical of the glaciated northeast United States. MODFLOW, a numerical groundwater-flow model, is used with groundwater observations, lidar topography, surface-water hydrology, and groundwater withdrawals to investigate SLR-induced changes in groundwater levels and vadose-zone thickness in New Hampshire's Seacoast. The SLR groundwater signal is detected up to 5 km from the coast, more than 3 times farther inland than projected surface-water flooding associated with SLR. Relative groundwater rise ranges from 38 to 98% of SLR within 1 km of the shoreline and drops below 4% between 4 and 5 km from the coast. The largest magnitude of SLR-induced groundwater rise occurs in the marine and estuarine deposits and land areas with tidal water bodies on three sides. In contrast, groundwater rise is dampened near streams. Groundwater inundation caused by 2 m of SLR is projected to contribute 48% of the total land inundation area in the City of Portsmouth with consequences for built and natural resources. Freshwater wetlands are projected to expand 3% by year 2030 increasing to 25% by year 2100 coupled with water-depth increases. These results imply that underground infrastructure and natural resources in coastal communities will be impacted by rising groundwater much farther inland than previously thought when considering only surface-water flooding from SLR.

  18. An Improved 20-Year Arctic Ocean Altimetric Sea Level Data Record

    DEFF Research Database (Denmark)

    Cheng, Yongcun; Andersen, Ole Baltazar; Knudsen, Per

    2015-01-01

    For ocean and climate research, it is essential to get long-term altimetric sea level data that is as accurate as possible. However, the accuracy of the altimetric data is frequently degraded in the interior of the Arctic Ocean due to the presence of seasonal or permanent sea ice. We have reproce...

  19. Modelling Morphological Response of Large Tidal Inlet Systems to Sea Level Rise

    NARCIS (Netherlands)

    Dissanayake, P.K.

    2011-01-01

    This dissertation qualitatively investigates the morphodynamic response of a large inlet system to IPCC projected relative sea level rise (RSLR). Adopted numerical approach (Delft3D) used a highly schematised model domain analogous to the Ameland inlet in the Dutch Wadden Sea. Predicted inlet

  20. Environmental safety evaluation in test sea disposal of low-level radioactive wastes

    International Nuclear Information System (INIS)

    1979-01-01

    The study results on the environmental safety in the test sea disposal of low-level wastes by Subcommittee on Radioactive Waste Safety Technology in Nuclear Safety Commission are given in connection with the test disposal of radioactive wastes into sea reported by the Nuclear Safety Bureau. The Subcommittee concludes that the effect of the test disposal of radioactive wastes into sea on the environment is extremely small. The contents are as follows. The full text of the report; attached data, (1) prediction of the concentrations of radioactive nuclides in sea, (2) calculation of the concentrations of radioactive nuclides in marine life with biological paths, and (3) estimation of exposure dose in general people; references (1) radiation exposure of the personnel engaged in sea disposal, (2) the effect of a sea disaster during ocean transport. (J.P.N.)

  1. Coral indicators of past sea-level change: A global repository of U-series dated benchmarks

    Science.gov (United States)

    Hibbert, Fiona D.; Rohling, Eelco J.; Dutton, Andrea; Williams, Felicity H.; Chutcharavan, Peter M.; Zhao, Cheng; Tamisiea, Mark E.

    2016-08-01

    Interglacial (LIG), where we use the available data with their uncertainties to assess probabilistically the time at which local sea levels exceed that of the present, which yields a mean age of 124.6 ka with 95% probability bounds at 118.5 and 129.5 ka. We conclude with identification of key outstanding issues relating to: (i) current incomplete understanding of tectonic setting (including the current lack of independent verification of uplift/subsidence rates and reliance of somewhat unsatisfactory, and circular, use of the elevation of Last Interglacial deposits); (ii) the depth-distributions of coral taxa and; (iii) the complete documentation of stratigraphic, geomorphological and other contextual information, with suggestions for strategies to address these issues.

  2. Sharing Remote and Local Information for Tracking Spring Breakup in the Mackenzie Delta and Beaufort Sea

    Science.gov (United States)

    Forbes, D. L.; Whalen, D.; Fraser, P.

    2015-12-01

    The Mackenzie Delta is the second largest on the Arctic Ocean, covering 13 000 km2. The annual flood regime in the delta is dominated by the spring snowmelt freshet and associated ice breakup, as water from the south arrives in the ice-covered delta and spreads over bottomfast and adjacent floating sea ice at the delta front. The complex processes of water-ice interaction, flow partitioning, and overbank flooding to replenish waters in 43 000 delta lakes threaten community, transportation, subsistence, and energy infrastructure in the delta. The annual breakup season is a time of rejuvenation, excitement, and anxiety for delta residents and stakeholders. To track the progress of breakup and meet the need for knowledge dissemination to the local communities, a Mackenzie-Beaufort breakup newsletter has been produced by Natural Resources Canada on a quasi-daily basis during the May-June spring flood season for 10 years, and distributed to an e-mail list that grew to over 300 subscribers. This provides near real-time tracking of water levels and breakup using on-line gauges (Environment Canada), daily MODIS satellite imagery (NASA), Landsat imagery (USGS) and intermittent radar imagery (various sources). In earlier years, information was also supplied from field programs operating in the delta during breakup, but changing priorities and funding have reduced the number of outside researchers present during these critical weeks. Meanwhile the number of local contributors has grown, providing observations and photographs to share with the local, regional and global readership. In this way the newsletter evolved into a two-way communication tool and community portal. The newsletter is a chronicle of each breakup season and a key resource for territorial and municipal managers, subsistence organizations, and emergency response agencies, with routine requests for specific imagery in areas of concern. With the completion of 10 years under the present model, we are exploring

  3. Impact of remote oceanic forcing on Gulf of Alaska sea levels and mesoscale circulation

    Science.gov (United States)

    Melsom, Arne; Metzger, E. Joseph; Hurlburt, Harley E.

    2003-11-01

    We examine the relative importance of regional wind forcing and teleconnections by an oceanic pathway for impact on interannual ocean circulation variability in the Gulf of Alaska. Any additional factors that contribute to this variability, such as freshwater forcing from river runoff, are disregarded. The study is based on results from numerical simulations, sea level data from tide gauge stations, and sea surface height anomalies from satellite altimeter data. At the heart of this investigation is a comparison of ocean simulations that include and exclude interannual oceanic teleconnections of an equatorial origin. Using lagged correlations, the model results imply that 70-90% of the interannual coastal sea level variance in the Gulf of Alaska can be related to interannual sea levels at La Libertad, Equador. These values are higher than the corresponding range from sea level data, which is 25-55%. When oceanic teleconnections from the equatorial Pacific are excluded in the model, the explained variance becomes about 20% or less. During poleward propagation the coastally trapped sea level signal in the model is less attenuated than the observed signal. In the Gulf of Alaska we find well-defined sea level peaks in the aftermath of El Niño events. The interannual intensity of eddies in the Gulf of Alaska also peaks after El Niño events; however, these maxima are less clear after weak and moderate El Niño events. The interannual variations in eddy activity intensity are predominantly governed by the regional atmospheric forcing.

  4. Remarks on the sea level records of the north Indian ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Unnikrishnan, A.S.

    variability in the tide gauge records along the coasts of the north Indian Ocean A. S. Unnikrishnan National Institute of Oceanography, Dona Paula, Goa, India 403004 e-mail: unni@nio.org Introduction Global sea-level rise has been relatively well... studied by making use of the coastal tide gauge data that are available (Woodworth and Player, 2003) through the Permanent Service for Mean Sea Level (PSMSL). However, studies on regional sea level rise have not gathered momentum, similar to those on a...

  5. Stable reconstruction of Arctic sea level for the 1950-2010 period

    OpenAIRE

    Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

    2016-01-01

    Reconstruction of historical Arctic sea level is generally difficult due to the limited coverage and quality of both tide gauge and altimetry data in the area. Here a strategy to achieve a stable and plausible reconstruction of Arctic sea level from 1950 to today is presented. This work is based on the combination of tide gauge records and a new 20-year reprocessed satellite altimetry derived sea level pattern. Hence the study is limited to the area covered by satellite altimetry (68ºN and 82...

  6. Impacts of climate change and sea level rise to Danish near shore ecosystems

    International Nuclear Information System (INIS)

    Vestergaard, P.

    2001-01-01

    Salt marshes and sand dunes are important types of coastal, terrestrial nature, which like other terrestrial ecosystems will be sensible to the future changes in climate, which have been predicted. Due to the processes acting in their morphogenesis and in the development and composition of their ecosystems, they will not least be influenced by sea level rise. Especially a strong impact of a sea level rise of about 50 cm (midrange of the projected global sea level rise) for the next century can be expected on Danish salt marshes, considering their limited vertical range (50-100 cm). (LN)

  7. Spatial Hedonic Models for Measuring the Impact of Sea-Level Rise on Coastal Real Estate

    OpenAIRE

    Okmyung Bin; Ben Poulter; Christopher F. Dumas; John C. Whitehead

    2009-01-01

    This study uses a unique integration of geospatial and hedonic property data to estimate the impact of sea-level rise on coastal real estate in North Carolina. North Carolina’s coastal plain is one of several large terrestrial systems around the world threatened by rising sea-levels. High-resolution topographic LIDAR (Light Detection and Ranging) data are used to provide accurate inundation maps for all properties that will be at risk under six different sea-level rise scenarios. A simulation...

  8. About local calibration curve of the Black Sea during the period 18000 - 3000 calendar years BP

    International Nuclear Information System (INIS)

    Slavova, K.

    2002-01-01

    Understanding the youngest geological Black Sea history requires that the age of the tested samples be accurately determined. The comparison between 234 U/ 230 Th and 14 C ages obtained on the Holocene samples demonstrate that 234 U/ 230 Th ages are accurate because they are in agreement with the dendrochonological calibration. Beyond 9100 calendar year BP it is proved that 14 C ages are systematically younger than 234 U/ 230 Th ages with a maximum difference of about 3000 years reached at about 20000 calendar years. This calls for converting the conventional 14 C ages in calendar ages. The procedure is called calibration. A local calibration Black Sea curve in which features of the Black Sea as a basin to be included is required, videlicet: correction of conventional ages for 'reservoir effect' - 60 years for TOC (Total Organic Carbon), 460 years for TCC (Total Carbonate Carbon) and for 'detrital carbon input - 580 years for TOC, 260 years for TCC. Such local calibration curve is constructed and proved in the article by using and comparing data from different dating methods (carbon 14, 234 U/ 230 Th, dendrochronology)

  9. Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise.

    Science.gov (United States)

    Hatfield, Jeff S; Reynolds, Michelle H; Seavy, Nathaniel E; Krause, Crystal M

    2012-08-01

    Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds. Conservation Biology ©2012 Society for Conservation Biology. No claim to original

  10. Population dynamics of Hawaiian seabird colonies vulnerable to sea-level rise

    Science.gov (United States)

    Hatfield, Jeff S.; Reynolds, Michelle H.; Seavy, Nathaniel E.; Krause, Crystal M.

    2012-01-01

    Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds.

  11. NEA Research and Environmental Surveillance Programme related to sea disposal of low-level radioactive waste

    International Nuclear Information System (INIS)

    Ruegger, B.; Templeton, W.L.; Gurbutt, P.

    1983-05-01

    Sea dumping operations of certain types of packaged low and medium-level radioactive wastes have been carried out since 1967 in the North-East Atlantic under the auspices of the OECD Nuclear Energy Agency. On the occasion of the 1980 review of the continued suitability of the North-East Atlantic site used for the disposal of radioactive waste, it was recommended that an effort should be made to increase the scientific data base relating to the oceanographic and biological characteristics of the dumping area. In particular, it was suggested that a site specific model of the transfer of radionuclides in the marine environment be developed, which would permit a better assessment of the potential radiation doses to man from the dumping of radioactive waste. To fulfill these objectives a research and environmental surveillance programme related to sea disposal of radioactive waste was set up in 1981 with the participation of thirteen Member countries and the International Laboratory for Marine Radioactivity of the IAEA in Monaco. The research program is focused on five research areas which are directly relevant to the preparation of more site-specific assessments in the future. They are: model development; physical oceanography; geochemistry; biology; and radiological surveillance. Promising results have already been obtained and more are anticipated in the not too distant future. An interim description of the NEA dumping site has been prepared which provides an excellent data base for this area (NEA 1983).It includes data in bathymetry, isopycnal topography, local and larger scale currents, sediment distribution and sedimentary processes, hydrochemistry, deep ocean biology and results of radiochemical analyses of sea water, sediments and biological materials. The modelling work is also well advanced allowing comparison of results obtained from different codes. After integration of the models, sensitivity analyses will provide indications for future research needs

  12. A Climate Change Adaptation Planning Process for Low-Lying, Communities Vulnerable to Sea Level Rise

    Directory of Open Access Journals (Sweden)

    Kristi Tatebe

    2012-09-01

    Full Text Available While the province of British Columbia (BC, Canada, provides guidelines for flood risk management, it is local governments’ responsibility to delineate their own flood vulnerability, assess their risk, and integrate these with planning policies to implement adaptive action. However, barriers such as the lack of locally specific data and public perceptions about adaptation options mean that local governments must address the need for adaptation planning within a context of scientific uncertainty, while building public support for difficult choices on flood-related climate policy and action. This research demonstrates a process to model, visualize and evaluate potential flood impacts and adaptation options for the community of Delta, in Metro Vancouver, across economic, social and environmental perspectives. Visualizations in 2D and 3D, based on hydrological modeling of breach events for existing dike infrastructure, future sea level rise and storm surges, are generated collaboratively, together with future adaptation scenarios assessed against quantitative and qualitative indicators. This ‘visioning package’ is being used with staff and a citizens’ Working Group to assess the performance, policy implications and social acceptability of the adaptation strategies. Recommendations based on the experience of the initiative are provided that can facilitate sustainable future adaptation actions and decision-making in Delta and other jurisdictions.

  13. Extended late Holocene relative sea-level histories for North Carolina, USA

    Science.gov (United States)

    Kemp, Andrew C.; Kegel, Jessica J.; Culver, Stephen J.; Barber, Donald C.; Mallinson, David J.; Leorri, Eduardo; Bernhardt, Christopher E.; Cahill, Niamh; Riggs, Stanley R.; Woodson, Anna L.; Mulligan, Ryan P.; Horton, Benjamin P.

    2017-01-01

    We produced ∼3000-year long relative sea-level (RSL) histories for two sites in North Carolina (USA) using foraminifera preserved in new and existing cores of dated salt-marsh sediment. At Cedar Island, RSL rose by ∼2.4 m during the past ∼3000 years compared to ∼3.3 m at Roanoke Island. This spatial difference arises primarily from differential GIA that caused late Holocene RSL rise to be 0.1–0.2 mm/yr faster at Roanoke Island than at Cedar Island. However, a non-linear difference in RSL between the two study regions (particularly from ∼0 CE to ∼1250 CE) indicates that additional local- to regional-scale processes drove centennial-scale RSL change in North Carolina. Therefore, the Cedar Island and Roanoke Island records should be considered as independent of one another. Between-site differences on sub-millennial timescales cannot be adequately explained by non-stationary tides, sediment compaction, or local sediment dynamics. We propose that a period of accelerating RSL rise from ∼600 CE to 1100 CE that is present at Roanoke Island (and other sites north of Cape Hatteras at least as far as Connecticut), but absent at Cedar Island (and other sites south of Cape Hatteras at least as far as northeastern Florida) is a local-to regional-scale effect of dynamic ocean and/or atmospheric circulation.

  14. Extended late Holocene relative sea-level histories for North Carolina, USA

    Science.gov (United States)

    Kemp, Andrew C.; Kegel, Jessica J.; Culver, Stephen J.; Barber, Donald C.; Mallinson, David J.; Leorri, Eduardo; Bernhardt, Christopher E.; Cahill, Niamh; Riggs, Stanley R.; Woodson, Anna L.; Mulligan, Ryan P.; Horton, Benjamin P.

    2017-03-01

    We produced ∼3000-year long relative sea-level (RSL) histories for two sites in North Carolina (USA) using foraminifera preserved in new and existing cores of dated salt-marsh sediment. At Cedar Island, RSL rose by ∼2.4 m during the past ∼3000 years compared to ∼3.3 m at Roanoke Island. This spatial difference arises primarily from differential GIA that caused late Holocene RSL rise to be 0.1-0.2 mm/yr faster at Roanoke Island than at Cedar Island. However, a non-linear difference in RSL between the two study regions (particularly from ∼0 CE to ∼1250 CE) indicates that additional local- to regional-scale processes drove centennial-scale RSL change in North Carolina. Therefore, the Cedar Island and Roanoke Island records should be considered as independent of one another. Between-site differences on sub-millennial timescales cannot be adequately explained by non-stationary tides, sediment compaction, or local sediment dynamics. We propose that a period of accelerating RSL rise from ∼600 CE to 1100 CE that is present at Roanoke Island (and other sites north of Cape Hatteras at least as far as Connecticut), but absent at Cedar Island (and other sites south of Cape Hatteras at least as far as northeastern Florida) is a local-to regional-scale effect of dynamic ocean and/or atmospheric circulation.

  15. A System of Systems Approach to Integrating Global Sea Level Change Application Programs

    Science.gov (United States)

    Bambachus, M. J.; Foster, R. S.; Powell, C.; Cole, M.

    2005-12-01

    The global sea level change application community has numerous disparate models used to make predications over various regional and temporal scales. These models have typically been focused on limited sets of data and optimized for specific areas or questions of interest. Increasingly, decision makers at the national, international, and local/regional levels require access to these application data models and want to be able to integrate large disparate data sets, with new ubiquitous sensor data, and use these data across models from multiple sources. These requirements will force the Global Sea Level Change application community to take a new system-of-systems approach to their programs. We present a new technical architecture approach to the global sea level change program that provides external access to the vast stores of global sea level change data, provides a collaboration forum for the discussion and visualization of data, and provides a simulation environment to evaluate decisions. This architectural approach will provide the tools to support multi-disciplinary decision making. A conceptual system of systems approach is needed to address questions around the multiple approaches to tracking and predicting Sea Level Change. A systems of systems approach would include (1) a forum of data providers, modelers, and users, (2) a service oriented architecture including interoperable web services with a backbone of Grid computing capability, and (3) discovery and access functionality to the information developed through this structure. Each of these three areas would be clearly designed to maximize communication, data use for decision making and flexibility and extensibility for evolution of technology and requirements. In contemplating a system-of-systems approach, it is important to highlight common understanding and coordination as foundational to success across the multiple systems. The workflow of science in different applications is often conceptually similar

  16. Tidal marsh plant responses to elevated CO2 , nitrogen fertilization, and sea level rise.

    Science.gov (United States)

    Adam Langley, J; Mozdzer, Thomas J; Shepard, Katherine A; Hagerty, Shannon B; Patrick Megonigal, J

    2013-05-01

    Elevated CO2 and nitrogen (N) addition directly affect plant productivity and the mechanisms that allow tidal marshes to maintain a constant elevation relative to sea level, but it remains unknown how these global change drivers modify marsh plant response to sea level rise. Here we manipulated factorial combinations of CO2 concentration (two levels), N availability (two levels) and relative sea level (six levels) using in situ mesocosms containing a tidal marsh community composed of a sedge, Schoenoplectus americanus, and a grass, Spartina patens. Our objective is to determine, if elevated CO2 and N alter the growth and persistence of these plants in coastal ecosystems facing rising sea levels. After two growing seasons, we found that N addition enhanced plant growth particularly at sea levels where plants were most stressed by flooding (114% stimulation in the + 10 cm treatment), and N effects were generally larger in combination with elevated CO2 (288% stimulation). N fertilization shifted the optimal productivity of S. patens to a higher sea level, but did not confer S. patens an enhanced ability to tolerate sea level rise. S. americanus responded strongly to N only in the higher sea level treatments that excluded S. patens. Interestingly, addition of N, which has been suggested to accelerate marsh loss, may afford some marsh plants, such as the widespread sedge, S. americanus, the enhanced ability to tolerate inundation. However, if chronic N pollution reduces the availability of propagules of S. americanus or other flood-tolerant species on the landscape scale, this shift in species dominance could render tidal marshes more susceptible to marsh collapse. © 2013 Blackwell Publishing Ltd.

  17. Relict benthic foraminifera in surface sediments off central east coast of India as indicator of sea level changes

    Digital Repository Service at National Institute of Oceanography (India)

    Rana, S.S.; Nigam, R.; Panchang, R.

    surface samples is characteristic of coral reef environment and has been inferred as evidence for past low sea levels. Based on extrapolation of previously published radiocarbon dates from the region, we propose a pliable sea level curve for the period...

  18. Switching between global and local levels: the level repetition effect and its hemispheric asymmetry

    Science.gov (United States)

    Kéïta, Luc; Bedoin, Nathalie; Burack, Jacob A.; Lepore, Franco

    2014-01-01

    The global level of hierarchical stimuli (Navon’s stimuli) is typically processed quicker and better than the local level; further differential hemispheric dominance is described for local (left hemisphere, LH) and global (right hemisphere, RH) processing. However, neuroimaging and behavioral data indicate that stimulus category (letter or object) could modulate the hemispheric asymmetry for the local level processing. Besides, when the targets are unpredictably displayed at the global or local level, the participant has to switch between levels, and the magnitude of the switch cost increases with the number of repeated-level trials preceding the switch. The hemispheric asymmetries associated with level switching is an unresolved issue. LH areas may be involved in carrying over the target level information in case of level repetition. These areas may also largely participate in the processing of level-changed trials. Here we hypothesized that RH areas underly the inhibitory mechanism performed on the irrelevant level, as one of the components of the level switching process. In an experiment using a within-subject design, hierarchical stimuli were briefly presented either to the right or to the left visual field. 32 adults were instructed to identify the target at the global or local level. We assessed a possible RH dominance for the non-target level inhibition by varying the attentional demands through the manipulation of level repetitions (two or gour repeated-level trials before the switch). The behavioral data confirmed a LH specialization only for the local level processing of letter-based stimuli, and detrimental effect of increased level repetitions before a switch. Further, data provides evidence for a RH advantage in inhibiting the non-target level. Taken together, the data supports the notion of the existence of multiple mechanisms underlying level-switch effects. PMID:24723903

  19. Thresholds of sea-level rise rate and sea-level rise acceleration rate in a vulnerable coastal wetland.

    Science.gov (United States)

    Wu, Wei; Biber, Patrick; Bethel, Matthew

    2017-12-01

    Feedbacks among inundation, sediment trapping, and vegetation productivity help maintain coastal wetlands facing sea-level rise (SLR). However, when the SLR rate exceeds a threshold, coastal wetlands can collapse. Understanding the threshold helps address key challenges in ecology-nonlinear response of ecosystems to environmental change, promotes communication between ecologists and resource managers, and facilitates decision-making in climate change policies. We studied the threshold of SLR rate and developed a new threshold of SLR acceleration rate on sustainability of coastal wetlands as SLR is likely to accelerate due to enhanced anthropogenic forces. Deriving these two thresholds depends on the temporal scale, the interaction of SLR with other environmental factors, and landscape metrics, which have not been fully accounted for before this study. We chose a representative marine-dominated estuary in the northern Gulf of Mexico, Grand Bay in Mississippi, to test the concept of SLR thresholds. We developed a mechanistic model to simulate wetland change and then derived the SLR thresholds for Grand Bay. The model results show that the threshold of SLR rate in Grand Bay is 11.9 mm/year for 2050, and it drops to 8.4 mm/year for 2100 using total wetland area as a landscape metric. The corresponding SLR acceleration rate thresholds are 3.02 × 10 -4  m/year 2 and 9.62 × 10 -5  m/year 2 for 2050 and 2100, respectively. The newly developed SLR acceleration rate threshold can help quantify the temporal lag before the rapid decline in wetland area becomes evident after the SLR rate threshold is exceeded, and cumulative SLR a wetland can adapt to under the SLR acceleration scenarios. Based on the thresholds, SLR that will adversely impact the coastal wetlands in Grand Bay by 2100 will fall within the likely range of SLR under a high warming scenario (RCP8.5), highlighting the need to avoid RCP8.5 to preserve these marshes.

  20. Quantifying and reporting greenhouse gas emissions at local level

    Directory of Open Access Journals (Sweden)

    Sόwka Izabela

    2017-01-01

    Full Text Available Cities as global centers of consumption and production often are a significant and growing source of greenhouse gas (GHG emissions. At the same time, local authorities are increasingly taking action on climate change by focusing on reducing GHG emissions and efficiency improvement opportunities. To assess and reduce the overall greenhouse gas emission level from an urban area, it is necessary to identify all the activities and processes which generate these emissions. GHG inventory gives an opportunity to get wider knowledge for city’s community about spatial emission processes and emissions contribution of key sources categories at the local scale. Inventory is being used for decision-making purposes and strategic planning in emission reduction policy. The goal of this paper was to clarify the major methodological challenges of GHG monitoring at the urban level. The paper is based on the discussion of different methods and approaches to assessing GHG emissions at the local level. It is presented sectoral GHGs emission trends in selected urban areas and compared CO2 emission level in different countries and metropolises and variable European cities guidance. The study determines the inventory tools of GHGs emission taking into account the characteristics of main sources at local levels.

  1. Relative sea level and coastal environments in arctic Alaska during Marine Isotope Stage 5

    Science.gov (United States)

    Farquharson, L. M.; Mann, D. H.; Jones, B. M.; Rittenour, T. M.; Grosse, G.; Groves, P.

    2015-12-01

    Marine Isotope Stage (MIS) 5 was characterized by marked fluctuations in climate, the warmest being MIS 5e (124-119 ka) when relative sea level (RSL) stood 2-10 m higher than today along many coastlines. In northern Alaska, marine deposits now 5-10 m above modern sea level are assigned to this time period and termed the Pelukian transgression (PT). Complicating this interpretation is the possibility that an intra-Stage 5 ice shelf extended along the Alaskan coast, causing isostatic depression along its grounded margins, which caused RSL highs even during periods of low, global RSL. Here we use optically stimulated luminescence (OSL) to date inferred PT deposits on the Beaufort Sea coastal plain. A transition from what we interpret to be lagoonal mud to sandy tidal flat deposits lying ~ 2.75 m asl dates to 113+/-18 ka. Above this, a 5-m thick gravelly barrier beach dates to 95 +/- 20 ka. This beach contains well-preserved marine molluscs, whale vertebrae, and walrus tusks. Pleistocene-aged ice-rich eolian silt (yedoma) blanket the marine deposits and date to 57.6 +/-10.9 ka. Our interpretation of this chronostratigraphy is that RSL was several meters higher than today during MIS 5e, and lagoons or brackish lakes were prevalent. Gravel barrier beaches moved onshore as local RSL rose further after MIS 5e. The error range of the OSL age of the barrier-beach unit spans the remaining four substages of MIS 5; however, the highstand of RSL on this arctic coastline appears to occurr after the warmest part of the last interglacial and appears not to be coeval with the eustatic maximum reached at lower latitudes during MIS 5. One possibility is that RSL along the Beaufort Sea coast was affected by isostatic depression caused by an ice shelf associated with widespread, intra-Stage 5 glaciation that was out of phase with lower latitude glaciation and whose extent and timing remains enigmatic.

  2. Do we have to take an acceleration of sea level rise into account?

    Science.gov (United States)

    Dillingh, D.; Baart, F.; de Ronde, J.

    2012-04-01

    In view of preservation of safety against inundation and of the many values and functions of the coastal zone, coastal retreat is no longer acceptable. That is why it was decided to maintain the Dutch coastline on its position in 1990. Later the preservation concept was extended to the Dutch coastal foundation, which is the area that encompasses all dune area's and hard sea defences and reaches seawards until the 20m depth contour line. Present Dutch coastal policy is to grow with sea level by means of sand nourishments. A main issue for the planning of sand nourishments is the rate of sea level rise, because that is the main parameter for the volume of the sand needed. The question is than relevant if we already have to take into account an acceleration of sea level rise. Six stations with long water level records, well spread along the Dutch coast, were analysed. Correction of the measured data was considered necessary for an adaptation of the NAP in 2005 as a consequence of movements of the top of the pleistoceen, on which the NAP bench marks have been founded, and for the 18.6 year (nodal) cycle in the time series of yearly mean sea levels. It has been concluded that along the Dutch coast no significant acceleration of sea level rise could be detected yet. Over the last 120 years sea level rose with an average speed of 19 cm per century relative to NAP (the Dutch ordnance datum). Time series shorter than about 50 years showed less robust estimates of sea level rise. Future sea level rise also needs consideration in view of the estimate of future sand nourishment volumes. Scenario's for sea level rise have been derived for the years 2050 and 2100 relative to 1990 by the KNMI (Dutch Met Office) in 2006 for the Dutch situation. Plausible curves have been drawn from 1990 tangent to the linear regression line in 1990 and forced through the high and low scenario projections for 2050 and 2100. These curves show discrepancies with measurements of the last decade

  3. QUESTION OF IMPROVEMENT OF BUDGET CONTROL AT THE LOCAL LEVEL

    Directory of Open Access Journals (Sweden)

    Oleg Vatslavskyi

    2016-11-01

    Full Text Available The aim is to analyse the current practice of budgetary control to develop its areas of improvement at the local level. The subject of the research is theoretical and methodological principles of functioning of budgetary control at the local level. The methodological basis of the study comprises research approaches, general theoretical principles of scientific knowledge, system of methods and techniques. The paper clarifies the nature of budgetary control at the local level. The main bodies that implement budget control, namely the State Audit Office, the Accounting Chamber, the State Treasury, the State Fiscal Service, financial and management departments are singled out. It is found that the leading part among all of the special budgetary control bodies in the rational and efficient use of local financial resources is performed by the State Audit Office. Analysis of the State Audit Office in three regions of Ukraine for the period 2013-2015 has been carried out. We distinguish two main types of violations that the State Audit Service reveals during its work at the local level: 1 shortfall in the financial resources of public enterprises, institutions and organizations; 2 violations that lead to illegal, non-target costs and shortages. It is proved that the efficiency of budgetary control is low. The paper states basic problems of budget control at the local level, namely, low income funds and reimbursements from violations revealed by regulatory agencies; insufficient work with the public to explain the problems of budget control and eliminate violations in the public sector; lack of a consolidated legal act, which would have regulated all the major components of budgetary control; insufficient use of controlling and auditing methods aimed at determining the effectiveness of budget funds; low preventive function on the part of budget control bodies. We offer ways to improve budget control at the local level through: standardization system of

  4. SEA in local land use planning - first experience in the Alpine States

    International Nuclear Information System (INIS)

    Jiricka, Alexandra; Proebstl, Ulrike

    2008-01-01

    In the Alpine area, planning decisions can result in far-reaching consequences because of the high sensitivity of the Alpine ecosystems. This article is based on two hypotheses: (1) The Alpine states/regions were aware of their sensitive environment and therefore recognized the necessity of introducing a comparable instrument to assess local land use planning. (2) By introducing this differentiated assessment tool, namely SEA, an increase in costs may be the consequence. However, better and more transparent planning can contribute to the enhancement of planning standards. To reveal the validity of these assumptions the legal implementation in the Alpine countries Austria, Germany, Italy and France was examined as well as first practical experience resulting from the determined procedures. The results of the implementation process in the four states were compared and discussed on the basis of selected process steps of SEA

  5. Impacts of Sea-Level Rise and Human Activity on a Tropical Continental Shelf, RN State, NE Brazil

    Science.gov (United States)

    Vital, H.; Barros Pereira, T. R.; Lira, H. F.; Tabosa, W. F.; Eichler, P.; Stattegger, K.; Sen Gupta, B. K.; Gomes, M. P.; Nogueira, M. L. D. S.; Pierri, G. C. S.

    2014-12-01

    The northeastern Brazilian, tropical coast-shelf system along the Atlantic Ocean is a sediment-starved zone, because of low relief, small drainage basins, and a semiarid climate. This work presents the major results of a study of environmental changes, particularly those related to Holocene sea-level rise, affecting the coast and shallow waters of Rio Grande do Norte (RN) State, NE Brazil. The methods included bottom-sediment characterization, bioindicator tracking, and integrated shallow-water geophysical investigation. This coastline is marked by active sea cliffs carved into tablelands alternating with reef- or dune-barrier sections, beach rocks and lagoons, whereas the shelf is a narrow, very shallow, and highly energetic system. Overall, the area is under the natural influence of tides (with a semidiurnal mesotidal regime) and the anthropogenic influence of salt exploration, oil industry, shrimp farms, tourism, and wind-farms. Sedimentation during the Holocene has been controlled mainly by sea-level variation, longshore currents, and the advance and westward propagation of active dunes along the coast. As in other areas around the world, growing numbers of permanent and seasonal residents choose to live at or near the ocean. Coastal erosion is a cause for concern along many Brazilian beaches, and several erosion hot spots are already recognized in RN State. Curves of Holocene relative sea-level variation were established for RN State, but the absence of long-term oceanographic observations in the last centuries or that of detailed altimetry maps hinders the evaluation of different risk scenarios at the local level. Nevertheless, impacts of the current sea-level rise and human activity can be observed along the RN coastal-shelf system. Particular aspects of the study, such as oil-spill monitoring, coastal-water sewage contamination, and coastal erosion, will be highlighted.

  6. Were sea level changes during the Pleistocene in the South Atlantic Coastal Plain a driver of speciation in Petunia (Solanaceae)?

    Science.gov (United States)

    Ramos-Fregonezi, Aline M C; Fregonezi, Jeferson N; Cybis, Gabriela B; Fagundes, Nelson J R; Bonatto, Sandro L; Freitas, Loreta B

    2015-05-20

    Quaternary climatic changes led to variations in sea level and these variations played a significant role in the generation of marine terrace deposits in the South Atlantic Coastal Plain. The main consequence of the increase in sea level was local extinction or population displacement, such that coastal species would be found around the new coastline. Our main goal was to investigate the effects of sea level changes on the geographical structure and variability of genetic lineages from a Petunia species endemic to the South Atlantic Coastal Plain. We employed a phylogeographic approach based on plastid sequences obtained from individuals collected from the complete geographic distribution of Petunia integrifolia ssp. depauperata and its sister group. We used population genetics tests to evaluate the degree of genetic variation and structure among and within populations, and we used haplotype network analysis and Bayesian phylogenetic methods to estimate divergence times and population growth. We observed three major genetic lineages whose geographical distribution may be related to different transgression/regression events that occurred in this region during the Pleistocene. The divergence time between the monophyletic group P. integrifolia ssp. depauperata and its sister group (P. integrifolia ssp. integrifolia) was compatible with geological estimates of the availability of the coastal plain. Similarly, the origin of each genetic lineage is congruent with geological estimates of habitat availability. Diversification of P. integrifolia ssp. depauperata possibly occurred as a consequence of the marine transgression/regression cycles during the Pleistocene. In periods of high sea level, plants were most likely restricted to a refuge area corresponding to fossil dunes and granitic hills, from which they colonized the coast once the sea level came down. The modern pattern of lineage geographical distribution and population variation was established by a range

  7. Mapping how local perturbations influence systems-level brain dynamics.

    Science.gov (United States)

    Gollo, Leonardo L; Roberts, James A; Cocchi, Luca

    2017-10-15

    The human brain exhibits a distinct spatiotemporal organization that supports brain function and can be manipulated via local brain stimulation. Such perturbations to local cortical dynamics are globally integrated by distinct neural systems. However, it remains unclear how local changes in neural activity affect large-scale system dynamics. Here, we briefly review empirical and computational studies addressing how localized perturbations affect brain activity. We then systematically analyze a model of large-scale brain dynamics, assessing how localized changes in brain activity at the different sites affect whole-brain dynamics. We find that local stimulation induces changes in brain activity that can be summarized by relatively smooth tuning curves, which relate a region's effectiveness as a stimulation site to its position within the cortical hierarchy. Our results also support the notion that brain hubs, operating in a slower regime, are more resilient to focal perturbations and critically contribute to maintain stability in global brain dynamics. In contrast, perturbations of peripheral regions, characterized by faster activity, have greater impact on functional connectivity. As a parallel with this region-level result, we also find that peripheral systems such as the visual and sensorimotor networks were more affected by local perturbations than high-level systems such as the cingulo-opercular network. Our findings highlight the importance of a periphery-to-core hierarchy to determine the effect of local stimulation on the brain network. This study also provides novel resources to orient empirical work aiming at manipulating functional connectivity using non-invasive brain stimulation. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Coastal Marsh Longevity, Ecological Succession, and Organic Carbon Dynamics During Early Holocene Sea-Level Rise

    Science.gov (United States)

    Vetter, L.; Schreiner, K. M.; Rosenheim, B. E.; Tornqvist, T. E.

    2016-02-01

    Coastal marsh environments perform essential ecosystem services, including nutrient filtering, soil organic matter storage, and storm surge abatement, yet much is still unknown about their formation and fate under periods of sea-level change. During the early Holocene (7-10 ka), rapid sea-level rise in coastal Louisiana was one of the primary controls over marsh development and longevity. Here, we investigate plant community composition and succession and soil organic matter storage in early Holocene coastal marshes in Louisiana using bulk elemental ratios, lignin phenol biomarkers and stable isotopes from peat layers. Sediment cores were collected in southeastern Louisiana and contain a record of an early Holocene transgressive sea-level sequence 16-25 m below present sea-level. The sedimentary record consists of an immature paleosol overlain by basal peat that accumulated in an estuarine marsh, overlain by marine lagoonal muds. A re-established marsh peat is present 1-4 m above the initial transition to marine conditions, indicating a sequence of marsh development, sea-level rise and onset of marine conditions, and then further marsh development as the rate of relative sea-level rise decelerated. Plant community composition in coastal marshes was determined through cupric oxide oxidation and lignin-phenol and non-lignin-phenol biomarker abundances. The degradation state of soil organic matter and the specific source of stabilized organic matter within the sedimentary peats were determined through lignin-phenol biomarker ratios. Organic matter sources ranged from terrestrial to marine over the course of sea-level rise, and different sites showed different amounts of marine organic matter influence and different levels of terrestrial organic matter degradation. These results have important implications for reconstructing the response of coastal marshes and their plant communities to accelerated rates of sea-level rise projected through 2100.

  9. Current and sea-level signals in periplatform ooze (Neogene, Maldives, Indian Ocean)

    Science.gov (United States)

    Betzler, Christian; Lüdmann, Thomas; Hübscher, Christian; Fürstenau, Jörn

    2013-05-01

    Periplatform ooze is an admixture of pelagic carbonate and sediment derived from neritic carbonate platforms. Compositional variations of periplatform ooze allow the reconstruction of past sea-level changes. Periplatform ooze formed during sea-level highstands is finer grained and richer in aragonite through the elevated input of material from the flooded platform compared to periplatform ooze formed during the episodes of lowered sea level. In many cases, however, the sea floor around carbonate platforms is subjected to bottom currents which are expected to affect sediment composition, i.e. through winnowing of the fine fraction. The interaction of sea-level<