WorldWideScience

Sample records for models sea level

  1. Improving sea level simulation in Mediterranean regional climate models

    Science.gov (United States)

    Adloff, Fanny; Jordà, Gabriel; Somot, Samuel; Sevault, Florence; Arsouze, Thomas; Meyssignac, Benoit; Li, Laurent; Planton, Serge

    2017-08-01

    For now, the question about future sea level change in the Mediterranean remains a challenge. Previous climate modelling attempts to estimate future sea level change in the Mediterranean did not meet a consensus. The low resolution of CMIP-type models prevents an accurate representation of important small scales processes acting over the Mediterranean region. For this reason among others, the use of high resolution regional ocean modelling has been recommended in literature to address the question of ongoing and future Mediterranean sea level change in response to climate change or greenhouse gases emissions. Also, it has been shown that east Atlantic sea level variability is the dominant driver of the Mediterranean variability at interannual and interdecadal scales. However, up to now, long-term regional simulations of the Mediterranean Sea do not integrate the full sea level information from the Atlantic, which is a substantial shortcoming when analysing Mediterranean sea level response. In the present study we analyse different approaches followed by state-of-the-art regional climate models to simulate Mediterranean sea level variability. Additionally we present a new simulation which incorporates improved information of Atlantic sea level forcing at the lateral boundary. We evaluate the skills of the different simulations in the frame of long-term hindcast simulations spanning from 1980 to 2012 analysing sea level variability from seasonal to multidecadal scales. Results from the new simulation show a substantial improvement in the modelled Mediterranean sea level signal. This confirms that Mediterranean mean sea level is strongly influenced by the Atlantic conditions, and thus suggests that the quality of the information in the lateral boundary conditions (LBCs) is crucial for the good modelling of Mediterranean sea level. We also found that the regional differences inside the basin, that are induced by circulation changes, are model-dependent and thus not

  2. Land-ice modeling for sea-level prediction

    Energy Technology Data Exchange (ETDEWEB)

    Lipscomb, William H [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2010-06-11

    There has been major progress in ice sheet modeling since IPCC AR4. We will soon have efficient higherorder ice sheet models that can run at ",1 km resolution for entire ice sheets, either standalone or coupled to GeMs. These models should significantly reduce uncertainties in sea-level predictions. However, the least certain and potentially greatest contributions to 21st century sea-level rise may come from ice-ocean interactions, especially in West Antarctica. This is a coupled modeling problem that requires collaboration among ice, ocean and atmosphere modelers.

  3. Synthesizing long-term sea level rise projections - the MAGICC sea level model v2.0

    Science.gov (United States)

    Nauels, Alexander; Meinshausen, Malte; Mengel, Matthias; Lorbacher, Katja; Wigley, Tom M. L.

    2017-06-01

    Sea level rise (SLR) is one of the major impacts of global warming; it will threaten coastal populations, infrastructure, and ecosystems around the globe in coming centuries. Well-constrained sea level projections are needed to estimate future losses from SLR and benefits of climate protection and adaptation. Process-based models that are designed to resolve the underlying physics of individual sea level drivers form the basis for state-of-the-art sea level projections. However, associated computational costs allow for only a small number of simulations based on selected scenarios that often vary for different sea level components. This approach does not sufficiently support sea level impact science and climate policy analysis, which require a sea level projection methodology that is flexible with regard to the climate scenario yet comprehensive and bound by the physical constraints provided by process-based models. To fill this gap, we present a sea level model that emulates global-mean long-term process-based model projections for all major sea level components. Thermal expansion estimates are calculated with the hemispheric upwelling-diffusion ocean component of the simple carbon-cycle climate model MAGICC, which has been updated and calibrated against CMIP5 ocean temperature profiles and thermal expansion data. Global glacier contributions are estimated based on a parameterization constrained by transient and equilibrium process-based projections. Sea level contribution estimates for Greenland and Antarctic ice sheets are derived from surface mass balance and solid ice discharge parameterizations reproducing current output from ice-sheet models. The land water storage component replicates recent hydrological modeling results. For 2100, we project 0.35 to 0.56 m (66 % range) total SLR based on the RCP2.6 scenario, 0.45 to 0.67 m for RCP4.5, 0.46 to 0.71 m for RCP6.0, and 0.65 to 0.97 m for RCP8.5. These projections lie within the range of the latest IPCC SLR

  4. Salt marsh stability modelled in relation to sea level rise

    Science.gov (United States)

    Bartholdy, Jesper; Bartholdy, Anders T.; Kroon, Aart

    2010-05-01

    Accretion on a natural backbarrier salt marsh was modeled as a function of high tide level, initial salt marsh level and distance to the source. Calibration of the model was based on up to ca 80 year old marker horizons, supplemented by 210Pb/137Cs datings and subsequent measurements of clay thickness. Autocompaction was incorporated in the model, and shown to play a major role for the translation of accretion rates measured as length per unit time to accumulation rates measured as mass per area per unit time. This is important, even for shallow salt marsh deposits for which it is demonstrated that mass depth down core can be directly related to the bulk dry density of the surface layer by means of a logarithmic function. The results allow for an evaluation of the use of marker horizons in the topmost layers and show that it is important to know the level of the marker in relation to the salt marsh base. In general, deeper located markers will indicate successively smaller accretion rates with the same sediment input. Thus, stability analysis made on the basis of newly established marker horizons will be biased and indicate salt marsh stabilities far above the correct level. Running the model with a constant sea level revealed that balance between the inner and the outer salt marsh deposition can not be achieved within a reasonable time scale. Likewise it is shown that only one specific sea level rise provides equilibrium for a given location on the salt marsh. With a higher sea level rise, the marsh at the specific location will eventually drown, whereas - with a sea level rise below this level - it will grow towards the top of the rising tidal frame. The short term variation of salt marsh accretion was found to correlate well with variations in the North Atlantic Oscillation - the NAO winter index. Comparisons between the geomorphological development of wind tide affected salt marshes, like those present on the Danish North Sea coasts, and primary astronomically

  5. Synthetic stratigraphy of epicontinental seas: a carbonate sedimentation model and its applications in sea level studies

    Energy Technology Data Exchange (ETDEWEB)

    Cisne, J.L.; Gildner, R.F.

    1984-04-01

    Carbonates from the central parts of epicontinental seas are ideal strata for detailed study of eustatic sea level change. On the basis of sedimentation model in which carbonate accumulation rate is directly proportional to water depth, we developed synthetic stratigraphies for sea level histories expected for post-glacial transgression and for constant and sinusoidally fluctuating ocean ridge volume increase. These histories give distinctly different trends for water depth as a function of stratigraphic position in the sections' bathymetric curves. In general, water depth is proportional to the rate of sea level rise. Depth-dependent sedimentation leads to a time lag between sea level fluctuation and corresponding depth fluctuation which, as examples show, can approach 10/sup 6/ years for depth fluctuations of even a few meters--a fundamental consideration for reconstructing sea level curves, time-correlating sections by bathymetric curves, and relating water depth on continents to ocean ridge volume. Bathymetric curves based on gradient analysis of fossil assemblages (coenocorrelation curves) for American Middle Ordovician sections approximate patterns expected for sinusoidally increasing sea level. The model's predictions are tested in an ''artificial experiment'' that takes advantage of differential subsidence between the craton's middle and its edge to make a difference in the bathymetric histories of sections that otherwise record the same sea level history. The depth dependence in sedimentation was that above wave base net accumulation per year was very roughly 3 x 10/sup -6/ of the water depth.

  6. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Big Branch Marsh NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Model SummaryChanges in tidal marsh area and habitat type in response to sea-level rise were modeled using the Sea Level Affecting Marshes Model (SLAMM 6) that...

  7. Salt marsh stability modelled in relation to sea level rise

    DEFF Research Database (Denmark)

    Bartholdy, Jesper; Bartholdy, Anders; Kroon, Aart

    2010-01-01

    Accretion on a natural backbarrier salt marsh was modeled as a function of high tide level, initial salt marsh level and distance to the source. Calibration of the model was based on up to ca 80 year old marker horizons, supplemented by 210Pb/137Cs datings and subsequent measurements of clay...... rise, the marsh at the specific location will eventually drown, whereas - with a sea level rise below this level – it will grow towards the top of the rising tidal frame. The short term variation of salt marsh accretion was found to correlate well with variations in the North Atlantic Oscillation...... - relatively quickly grow above the level of the highest astronomical tide, whereas this - in practice - will never happen for the latter....

  8. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Marin Islands NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Marin...

  9. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Rappahannock NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  10. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Bayou Sauvage NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Bayou...

  11. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Mashpee NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  12. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Back Bay NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Back...

  13. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Cedar Keys NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Cedar...

  14. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Breton NWR [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  15. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Archie Carr NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  16. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Chassahowitzka NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  17. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Grand Bay NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Grand...

  18. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Blackwater NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  19. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Cedar Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Cedar...

  20. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Harris Neck NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  1. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Pine Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Pine...

  2. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Delta NWR : Revised [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Delta...

  3. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Currituck NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  4. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Nansemond NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  5. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Blackbeard Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  6. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Guam NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Guam...

  7. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Bombay Hook NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  8. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Amagansett NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  9. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Wolf Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Wolf...

  10. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Monomoy NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  11. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Potomac River NWR Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  12. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Hobe Sound NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Hobe...

  13. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to St. Marks NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on St....

  14. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to John Heinz NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on John...

  15. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Edwin B. Forsythe NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Edwin...

  16. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Swanquarter NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  17. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Pinckney Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  18. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Pelican Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  19. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Moosehorn NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  20. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Crocodile Lake NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  1. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Merritt Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  2. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Cape May NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Cape...

  3. Sea level rise projection in the South China Sea from CMIP5 models

    Institute of Scientific and Technical Information of China (English)

    HUANG Chuanjiang; QIAO Fangli

    2015-01-01

    Future potential sea level change in the South China Sea (SCS) is estimated by using 24 CMIP5 models under different representative concentration pathway (RCP) scenarios. By the end of the 21st century (2081–2100 relative to 1986–2005), the multimodel ensemble mean dynamic sea level (DSL) is projected to rise 0.9, 1.6, and 1.1 cm under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively, resulting in a total sea level rise (SLR) of 40.9, 48.6, and 64.1 cm in the SCS. It indicates that the SCS will experience a substantial SLR over the 21st century, and the rise is only marginal larger than the global mean SLR. During the same period, the steric sea level (SSL) rise is estimated to be 6.7, 10.0, and 15.3 cm under the three scenarios, respectively, which accounts only for 16%, 21% and 24% of the total SLR in this region. The changes of the SSL in the SCS are almost out of phase with those of the DSL for the three scenarios. The central deep basin has a slightly weak DSL rise, but a strong SSL rise during the 21st century, compared with the north and southwest shelves.

  4. Modelling sea level data from China and Malay-Thailand to estimate Holocene ice-volume equivalent sea level change

    Science.gov (United States)

    Bradley, Sarah L.; Milne, Glenn A.; Horton, Benjamin P.; Zong, Yongqiang

    2016-04-01

    This study presents a new model of Holocene ice-volume equivalent sea level (ESL), extending a previously published global ice sheet model (Bassett et al., 2005), which was unconstrained from 10 kyr BP to present. This new model was developed by comparing relative sea level (RSL) predictions from a glacial isostatic adjustment (GIA) model to a suite of Holocene sea level index points from China and Malay-Thailand. Three consistent data-model misfits were found using the Bassett et al. (2005) model: an over-prediction in the height of maximum sea level, the timing of this maximum, and the temporal variation of sea level from the time of the highstand to present. The data-model misfits were examined for a large suite of ESL scenarios and a range of earth model parameters to determine an optimum model of Holocene ESL. This model is characterised by a slowdown in melting at ∼7 kyr BP, associated with the final deglaciation of the Laurentide Ice Sheet, followed by a continued rise in ESL until ∼1 kyr BP of ∼5.8 m associated with melting from the Antarctic Ice Sheet. It was not possible to identify an earth viscosity model that provided good fits for both regions; with the China data preferring viscosity values in the upper mantle of less than 1.5 × 1020 Pa s and the Malay-Thailand data preferring greater values. We suggest that this inference of a very weak upper mantle for the China data originates from the nearby subduction zone and Hainan Plume. The low viscosity values may also account for the lack of a well-defined highstand at the China sites.

  5. Humboldt Nay NWR Sea-level rise modeling

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Baseline information required to assess sea-level rise impacts to marsh habitats will be compiled. The project will provide relevant information to local managers...

  6. 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...

  7. Modeling storm and sea level rise impacts on marsh transgression

    Science.gov (United States)

    Carr, J. A.; Guntenspergen, G. R.; Kirwan, M. L.

    2016-12-01

    Coastal salt marsh systems provide critical ecosystem services, including key habitat and coastal protection. Both lateral extent, and vertical stability of salt marshes to sea level rise have been shown to be functions of both biotic, and abiotic drivers and feedbacks. As a result, the ecogeomorphic evolution of the system can exhibit strong non-linearities, discontinuities and thresholds. We developed a two-dimensional transect model to explore controls on marsh lateral extent, vertical stability and the potential for marsh transgression inland and upland. Salt marsh and upland regions in the model are discretized in 1 m increments with inundation frequency determined by the elevation of the individual cells, organogenic soil formation and mineral deposition rates, and the history of stochastic water levels. The transect extends from an idealized back barrier bay across the salt marsh platform and into the upland forest and is forced with auto and cross correlated synthetic stochastic wind speed, wind direction and water levels. The model incorporates key feedbacks between fetch, wave growth and subsequent lateral erosion rates and sediment supply to the marsh platform. Deposition of mineral sediment from the bay and/or internal ponds onto the marsh platform cells is dependent both on the inundation frequency and distance from a marsh edge. For each element along the transect, a Markov chain successional model was implemented that considers six distinct states, grass/saltmarsh, seedling, sapling, tree, dead standing tree, and bare. A non-static transition probability matrix, dependent on both inundation of the element and the prior vegetation state, was used in order to allow for feedbacks, both positive and negative, among different vegetation states and environmental drivers. The model was used to examine the qualitative behavior of the coupled systems under varied rates of sea level rise, external sediment supply, wind and storm statistics, tidal range, upland

  8. The history of Post-Miocene sea level change: Inferences from stratigraphic modeling of Enewetak Atoll

    Science.gov (United States)

    Quinn, Terrence M.

    1991-04-01

    The history of post-Miocene sea level change has been investigated using a quantitative, one-dimensional stratigraphic forward model. The stratigraphic model produces synthetic stratigraphies, including mineralogy and sediment age versus depth, in response to changes in sea level, subsidence, sedimentation, and diagenesis. Model outputs, using sea level curves inferred from passive margin sequence stratigraphy and deep-sea foraminiferal oxygen isotope stratigraphy, were compared to the post-Miocene stratigraphy of Enewetak Atoll. Modeling results support high-frequency (104 to 105 years) fluctuations of post-Miocene sea level. Post-Miocene sea level elevations significantly greater than modern sea level elevation are not easily reconciled with the stratigraphy of Enewetak Atoll. Model/data fit is maximized when a rapid subsidence rate for Enewetak Atoll is used. Alternatively, model/data fit may be maximized using a lower subsidence rate for Enewetak and having post-Miocene sea level elevations significantly lower than modem sea level elevation. Given the present state of knowledge, much work is still needed to accurately decipher the record of post-Miocene sea level change.

  9. Neutral models as a way to evaluate the Sea Level Affecting Marshes Model (SLAMM)

    Science.gov (United States)

    A commonly used landscape model to simulate wetland change – the Sea Level Affecting Marshes Model(SLAMM) – has rarely been explicitly assessed for its prediction accuracy. Here, we evaluated this model using recently proposed neutral models – including the random constraint matc...

  10. Modeling radium distribution in coastal aquifers during sea level changes: The Dead Sea case

    Science.gov (United States)

    Kiro, Yael; Yechieli, Yoseph; Voss, Clifford I.; Starinsky, Abraham; Weinstein, Yishai

    2012-01-01

    We present a new approach to studying the behavior of radium isotopes in a coastal aquifer. In order to simulate radium isotope distributions in the dynamic flow field of the Dead Sea aquifer, a multi-species density dependent flow model (SUTRA-MS) was used. Field data show that the activity of 226Ra decreases from 140 to 60 dpm/L upon entering the aquifer from the Dead Sea, and then further decreases linearly due to mixing with Ra-poor fresh water. On the other hand, an increase is observed in the activity of the shorter-lived isotopes (up to 52 dpm/L 224Ra and 31 dpm/L 223Ra), which are relatively low in Dead Sea water (up to 2.5 dpm/L 224Ra and 0.5 dpm/L 223Ra). The activities of the short lived radium isotopes also decrease with decreasing salinity, which is due to the effect of salinity on the adsorption of radium. The relationship between 224Ra and salinity suggests that the adsorption partition coefficient (K) is linearly related to salinity. Simulations of the steady-state conditions, show that the distance where equilibrium activity is attained for each radium isotope is affected by the isotope half-life, K and the groundwater velocity, resulting in a longer distance for the long-lived radium isotopes. K affects the radium distribution in transient conditions, especially that of the long-lived radium isotopes. The transient conditions in the Dead Sea system, with a 1 m/yr lake level drop, together with the radium field data, constrains K to be relatively low (226Ra cannot be explained by adsorption, and it is better explained by removal via coprecipitation, probably with barite or celestine.

  11. The coherence of small island sea-level with the wider ocean: a model study

    Directory of Open Access Journals (Sweden)

    Joanne Williams

    2012-09-01

    Full Text Available Studies comparing tide gauge measurements with sea level from nearby satellite altimetry have shown good agreement for some islands, and poor agreement for others, though no explanation has been offered. Using the 1/12° OCCAM ocean model, we investigate the relationship between sea level at small, open-ocean islands, and offshore sea level. For every such island or seamount in the model, we compare the shallow-water sea level with the steric and bottom pressure variability in a neighboring ring of deep water. We find a latitude-dependent range of frequencies for which off-shore sea level is poorly correlated with island sea level. This poor coherence occurs in a spectral region for which steric signals dominate, but are unable to propagate as baroclinic Rossby waves. This mode of decoupling does not arise because of island topography, as the same decoupling is seen between deep ocean points and surrounding rings.

  12. 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 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.

  13. Implications of sediment redistribution on modeled sea-level changes over millennial timescales

    Science.gov (United States)

    Ferrier, Ken

    2016-04-01

    Sea level is a critical link in feedbacks among topography, tectonics, and climate. Over millennial timescales, changes in sea level reshape river networks, regulate organic carbon burial, influence sediment deposition, and set moving boundary conditions for landscape evolution. Sea-level changes influence tectonics by regulating rates and patterns of erosion and deposition, which perturb the surface loads that drive geodynamic processes at depth. These interactions are complex because sea-level changes are influenced by the geomorphic processes that they themselves modify, since sediment redistribution deforms the gravitational and crustal elevation fields that define sea level. A recent advance in understanding the coupling between sea level, tectonics, and topography was the incorporation of sediment redistribution into a gravitationally self-consistent sea-level model, which permits the computation of sea-level responses to erosion and deposition (Dalca et al., 2013, Geophysical Journal International). Here I use this model to quantify changes in sea level resulting from the erosion of some of the most rapidly eroding sites on Earth and the deposition of sediment offshore. These model results show that the sea-level fingerprints of sediment redistribution are strongly variable in space, and that they can represent a significant component of the total sea level change since the last interglacial. This work provides a basis for understanding a fundamental driver of landscape evolution at some of Earth's most geomorphically dynamic sites, and thus aids investigation of the couplings among tectonics, climate, and topography. References Dalca A.V., Ferrier K.L., Mitrovica J.X., Perron J.T., Milne G.A., Creveling J.R., 2013. On postglacial sea level - III. Incorporating sediment redistribution. Geophysical Journal International, doi: 10.1093/gji/ggt089.

  14. 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

  15. Statistical modeling and trend detection of extreme sea level records in the Pearl River Estuary

    Science.gov (United States)

    Wang, Weiwen; Zhou, Wen

    2017-03-01

    Sea level rise has become an important issue in global climate change studies. This study investigates trends in sea level records, particularly extreme records, in the Pearl River Estuary, using measurements from two tide gauge stations in Macau and Hong Kong. Extremes in the original sea level records (daily higher high water heights) and in tidal residuals with and without the 18.6-year nodal modulation are investigated separately. Thresholds for defining extreme sea levels are calibrated based on extreme value theory. Extreme events are then modeled by peaks-over-threshold models. The model applied to extremes in original sea level records does not include modeling of their durations, while a geometric distribution is added to model the duration of extremes in tidal residuals. Realistic modeling results are recommended in all stationary models. Parametric trends of extreme sea level records are then introduced to nonstationary models through a generalized linear model framework. The result shows that, in recent decades, since the 1960s, no significant trends can be found in any type of extreme at any station, which may be related to a reduction in the influence of tropical cyclones in the region. For the longer-term record since the 1920s at Macau, a regime shift of tidal amplitudes around the 1970s may partially explain the diverse trend of extremes in original sea level records and tidal residuals.

  16. Current state and future perspectives on coupled ice-sheet – sea-level modelling

    NARCIS (Netherlands)

    de Boer, B.; Stocchi, P.; Whitehouse, P.L.; van de Wal, R.S.W.

    2017-01-01

    The interaction between ice-sheet growth and retreat and sea-level change has been an established fieldof research for many years. However, recent advances in numerical modelling have shed new light on theprecise interaction of marine ice sheets with the change in near-field sea level, and the

  17. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Green Cay National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Green...

  18. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Conscience Point NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  19. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Rhode Island NWR Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Rhode...

  20. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Great Bay NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Great...

  1. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Great White Heron NWR : Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Great...

  2. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Bayou Teche NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Bayou...

  3. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Supawna Meadows NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  4. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Alligator River National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  5. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Caloosahatchee National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  6. Application of the Sea-Level Affecting Marshes Model (SLAMM 6) to Cedar Keys NWR : Revised report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Cedar...

  7. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Bon Secour National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Bon...

  8. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Eastern Neck NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  9. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Pinellas National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  10. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Shell Keys National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Shell...

  11. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.1) to Oyster Bay NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Oyster...

  12. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Mandalay National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  13. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Nomans Land Island NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Nomans...

  14. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Crystal River NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on...

  15. 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 evolut

  16. Salt marsh stability modelled in relation to sea level rise

    DEFF Research Database (Denmark)

    Bartholdy, Jesper; Bartholdy, Anders; Kroon, Aart

    2010-01-01

    Accretion on a natural backbarrier salt marsh was modeled as a function of high tide level, initial salt marsh level and distance to the source. Calibration of the model was based on up to ca 80 year old marker horizons, supplemented by 210Pb/137Cs datings and subsequent measurements of clay...... thickness. Autocompaction was incorporated in the model, and shown to play a major role for the translation of accretion rates measured as length per unit time to accumulation rates measured as mass per area per unit time. This is important, even for shallow salt marsh deposits for which it is demonstrated...... that mass depth down core can be directly related to the bulk dry density of the surface layer by means of a logarithmic function. The results allow for an evaluation of the use of marker horizons in the topmost layers and show that it is important to know the level of the marker in relation to the salt...

  17. Sea level and vertical motion of continents from dynamic earth models since the Late Cretaceous

    OpenAIRE

    Spasojevic, Sonja; Gurnis, Michael

    2012-01-01

    Dynamic earth models are used to better understand the impact of mantle dynamics on the vertical motion of continents and regional and global sea level change since the Late Cretaceous. A hybrid approach combines inverse and forward models of mantle convection and accounts for the principal contributors to long-term sea level change: the evolving distribution of ocean floor age, dynamic topography in oceanic and continental regions, and the geoid. We infer the relative importance of dynamic v...

  18. Final report for sea-level rise response modeling for San Francisco Bay estuary tidal marshes

    Science.gov (United States)

    Takekawa, John Y.; Thorne, Karen M.; Buffington, Kevin J.; Spragens, Kyle A.; Swanson, Kathleen M.; Drexler, Judith Z.; Schoellhamer, David H.; Overton, Cory T.; Casazza, Michael L.

    2013-01-01

    The International Panel on Climate Change has identified coastal ecosystems as areas that will be disproportionally affected by climate change. Current sea-level rise projections range widely with 0.57 to 1.9 meters increase in mea sea level by 2100. The expected accelerated rate of sea-level rise through the 21st century will put many coastal ecosystems at risk, especially those in topographically low-gradient areas. We assessed marsh accretion and plant community state changes through 2100 at 12 tidal salt marshes around San Francisco Bay estuary with a sea-level rise response model. Detailed ground elevation, vegetation, and water level data were collected at all sites between 2008 and 2011 and used as model inputs. Sediment cores (taken by Callaway and others, 2012) at four sites around San Francisco Bay estuary were used to estimate accretion rates. A modification of the Callaway and others (1996) model, the Wetland Accretion Rate Model for Ecosystem Resilience (WARMER), was utilized to run sea-level rise response models for all sites. With a mean sea level rise of 1.24 m by 2100, WARMER projected that the vast majority, 95.8 percent (1,942 hectares), of marsh area in our study will lose marsh plant communities by 2100 and to transition to a relative elevation range consistent with mudflat habitat. Three marshes were projected to maintain marsh vegetation to 2100, but they only composed 4.2 percent (85 hectares) of the total marsh area surveyed.

  19. 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

  20. Modeling River Networks in the Continental Shelf during Sea Level Cycles

    Science.gov (United States)

    Fagherazzi, S.; Wiberg, P. L.

    2003-12-01

    Several processes influence the development of fluvial networks in the continental shelf during sea level low stands. In order to understand the specific role of each process and quantify its influence on channel formation and incision, the Detachment Limited Model (DeLiM) (Howard, 1994) has been applied to several shelf configurations and with different sea-level curves. The computer model incorporates deltaic deposition on the continental shelf as well as sea-level oscillations and is parameterized with Virginia coastal plain data. Simulations show that the major factor controlling incision and channel development is the tendency of streams to reach an equilibrium (graded) configuration. If, for a given river discharge and shelf slope, the sediment load is less than that required to be at grade, channel incision will occur in the exposed shelf until the river long profile is in equilibrium with the current sea level (base level). The geometry and thickness of sediments deposited in deltas and estuaries have a minor influence on the total channel incision, but are of fundamental importance for the spatial development of the channel network. Model results show that the detailed structure of sea level oscillations is important for sediment redistribution and channel changes. Conceptual models that consider a mere succession of sea level high stands and low stands are oversimplified and miss the complex response of the system to gradual sea level oscillations. The initial shelf topography strongly characterizes the future network development. During the simulations the drainage network is initially strongly fragmented, but gradually becomes integrated through depression infilling and dissection of steep scarps. Finally the role of coastal processes is of crucial importance for sediment redistribution and shelf topography modification during sea-level oscillations.

  1. Sea level driven marsh expansion in a coupled model of marsh erosion and migration

    Science.gov (United States)

    Kirwan, Matthew L.; Walters, David C.; Reay, William G.; Carr, Joel A.

    2016-05-01

    Coastal wetlands are among the most valuable ecosystems on Earth, where ecosystem services such as flood protection depend nonlinearly on wetland size and are threatened by sea level rise and coastal development. Here we propose a simple model of marsh migration into adjacent uplands and couple it with existing models of seaward edge erosion and vertical soil accretion to explore how ecosystem connectivity influences marsh size and response to sea level rise. We find that marsh loss is nearly inevitable where topographic and anthropogenic barriers limit migration. Where unconstrained by barriers, however, rates of marsh migration are much more sensitive to accelerated sea level rise than rates of edge erosion. This behavior suggests a counterintuitive, natural tendency for marsh expansion with sea level rise and emphasizes the disparity between coastal response to climate change with and without human intervention.

  2. Bayesian methods for model uncertainty analysis with application to future sea level rise

    Energy Technology Data Exchange (ETDEWEB)

    Patwardhan, A.; Small, M.J.

    1992-01-01

    In no other area is the need for effective analysis of uncertainty more evident than in the problem of evaluating the consequences of increasing atmospheric concentrations of radiatively active gases. The major consequences of concern is global warming, with related environmental effects that include changes in local patterns of precipitation, soil moisture, forest and agricultural productivity, and a potential increase in global mean sea level. In order to identify an optimum set of responses to sea level change, a full characterization of the uncertainties associated with the predictions of future sea level rise is essential. The paper addresses the use of data for identifying and characterizing uncertainties in model parameters and predictions. The Bayesian Monte Carlo method is formally presented and elaborated, and applied to the analysis of the uncertainty in a predictive model for global mean sea level change.

  3. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

    Directory of Open Access Journals (Sweden)

    Roshan GholamReza

    2012-12-01

    Full Text Available Abstract The rapid rise of Caspian Sea water level (about 2.25 meters since 1978 has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006 and future (2025-2100 time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3. The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21. The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82 between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  4. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations.

    Science.gov (United States)

    Roshan, Gholamreza; Moghbel, Masumeh; Grab, Stefan

    2012-12-12

    The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  5. 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

  6. Modeling Sea-Level Change using Errors-in-Variables Integrated Gaussian Processes

    Science.gov (United States)

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

    2014-05-01

    We perform Bayesian inference on historical and late Holocene (last 2000 years) rates of sea-level change. The data that form the input to our model are tide-gauge measurements and proxy reconstructions from cores of coastal sediment. To accurately estimate rates of sea-level change and reliably compare tide-gauge compilations with proxy reconstructions it is necessary to account for the uncertainties that characterize each dataset. Many previous studies used simple linear regression models (most commonly polynomial regression) resulting in overly precise rate estimates. The model we propose uses an integrated Gaussian process approach, where a Gaussian process prior is placed on the rate of sea-level change and the data itself is modeled as the integral of this rate process. The non-parametric Gaussian process model is known to be well suited to modeling time series data. The advantage of using an integrated Gaussian process is that it allows for the direct estimation of the derivative of a one dimensional curve. The derivative at a particular time point will be representative of the rate of sea level change at that time point. The tide gauge and proxy data are complicated by multiple sources of uncertainty, some of which arise as part of the data collection exercise. Most notably, the proxy reconstructions include temporal uncertainty from dating of the sediment core using techniques such as radiocarbon. As a result of this, the integrated Gaussian process model is set in an errors-in-variables (EIV) framework so as to take account of this temporal uncertainty. The data must be corrected for land-level change known as glacio-isostatic adjustment (GIA) as it is important to isolate the climate-related sea-level signal. The correction for GIA introduces covariance between individual age and sea level observations into the model. The proposed integrated Gaussian process model allows for the estimation of instantaneous rates of sea-level change and accounts for all

  7. 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...

  8. 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

  9. Predicting Land-Ice Retreat and Sea-Level Rise with the Community Earth System Model

    Energy Technology Data Exchange (ETDEWEB)

    Lipscomb, William [Los Alamos National Laboratory

    2012-06-19

    Coastal stakeholders need defensible predictions of 21st century sea-level rise (SLR). IPCC assessments suggest 21st century SLR of {approx}0.5 m under aggressive emission scenarios. Semi-empirical models project SLR of {approx}1 m or more by 2100. Although some sea-level contributions are fairly well constrained by models, others are highly uncertain. Recent studies suggest a potential large contribution ({approx}0.5 m/century) from the marine-based West Antarctic Ice Sheet, linked to changes in Southern Ocean wind stress. To assess the likelihood of fast retreat of marine ice sheets, we need coupled ice-sheet/ocean models that do not yet exist (but are well under way). CESM is uniquely positioned to provide integrated, physics based sea-level predictions.

  10. Last Interglacial climate and sea-level evolution from a coupled ice sheet-climate model

    Science.gov (United States)

    Goelzer, Heiko; Huybrechts, Philippe; Loutre, Marie-France; Fichefet, Thierry

    2016-12-01

    As the most recent warm period in Earth's history with a sea-level stand higher than present, the Last Interglacial (LIG, ˜ 130 to 115 kyr BP) is often considered a prime example to study the impact of a warmer climate on the two polar ice sheets remaining today. Here we simulate the Last Interglacial climate, ice sheet, and sea-level evolution with the Earth system model of intermediate complexity LOVECLIM v.1.3, which includes dynamic and fully coupled components representing the atmosphere, the ocean and sea ice, the terrestrial biosphere, and the Greenland and Antarctic ice sheets. In this setup, sea-level evolution and climate-ice sheet interactions are modelled in a consistent framework.Surface mass balance change governed by changes in surface meltwater runoff is the dominant forcing for the Greenland ice sheet, which shows a peak sea-level contribution of 1.4 m at 123 kyr BP in the reference experiment. Our results indicate that ice sheet-climate feedbacks play an important role to amplify climate and sea-level changes in the Northern Hemisphere. The sensitivity of the Greenland ice sheet to surface temperature changes considerably increases when interactive albedo changes are considered. Southern Hemisphere polar and sub-polar ocean warming is limited throughout the Last Interglacial, and surface and sub-shelf melting exerts only a minor control on the Antarctic sea-level contribution with a peak of 4.4 m at 125 kyr BP. Retreat of the Antarctic ice sheet at the onset of the LIG is mainly forced by rising sea level and to a lesser extent by reduced ice shelf viscosity as the surface temperature increases. Global sea level shows a peak of 5.3 m at 124.5 kyr BP, which includes a minor contribution of 0.35 m from oceanic thermal expansion. Neither the individual contributions nor the total modelled sea-level stand show fast multi-millennial timescale variations as indicated by some reconstructions.

  11. The sea-level fingerprint of the Antarctic ice sheet: an ensemble GIA modelling approach

    Science.gov (United States)

    Spada, Giorgio; Galassi, Gaia; Melini, Daniele

    2017-04-01

    During the last decade, Glacial Isostatic Adjustment (GIA) modelling has seen a considerable development, stimulated by the increasing number and quality of sea-level observations and of various geodetic constraints. The fundamental equation of GIA (the Sea Level Equation) accounts for a number of physical ingredients that make GIA modelling quite realistic, such as rotational effects on sea-level change, the migration of the shorelines, and the time-evolving topography in the presence of marine based ice. However, concerning the spatiotemporal distribution of the late-Pleistocene ice sheets, the GIA models published in the literature by different groups are characterised by significantly different features. These are the volumes of the ice sheets at the Last Glacial Maximum, the presence and the duration of abrupt melting episodes (meltwater pulses) and the timing of the end of deglaciation. These differences can be mainly attributed to the different sets of proxies employed to constrain the melting chronology and, sometimes, to different assumptions about the Earth's viscosity profile. One of most important sources of uncertainty is the melting chronology of the Antarctic ice sheet, which is poorly constrained by the limited amount of relative sea-level data available in the near field of the ice sheet. To test whether the GIA models developed so far for the deglaciation of Antarctic ice sheet are converging or not towards a unique solution, here we collectively consider the models of the melting history of Antarctica published in the literature so far and for each of them we solve the Sea Level Equation. Following a multi-model ensemble approach, we estimate the ensemble mean and its uncertainty, in terms of the geometry and of the time history of the sea-level fingerprints.

  12. The sea level response to ice sheet freshwater forcing in the Community Earth System Model

    Science.gov (United States)

    Slangen, Aimée B. A.; Lenaerts, Jan T. M.

    2016-10-01

    We study the effect of a realistic ice sheet freshwater forcing on sea-level change in the fully coupled Community Earth System Model (CESM) showing not only the effect on the ocean density and dynamics, but also the gravitational response to mass redistribution between ice sheets and the ocean. We compare the ‘standard’ model simulation (NO-FW) to a simulation with a more realistic ice sheet freshwater forcing (FW) for two different forcing scenario’s (RCP2.6 and RCP8.5) for 1850-2100. The effect on the global mean thermosteric sea-level change is small compared to the total thermosteric change, but on a regional scale the ocean steric/dynamic change shows larger differences in the Southern Ocean, the North Atlantic and the Arctic Ocean (locally over 0.1 m). The gravitational fingerprints of the net sea-level contributions of the ice sheets are computed separately, showing a regional pattern with a magnitude that is similar to the difference between the NO-FW and FW simulations of the ocean steric/dynamic pattern. Our results demonstrate the importance of ice sheet mass loss for regional sea-level projections in light of the projected increasing contribution of ice sheets to future sea-level rise.

  13. Sensitivity of the Baltic Sea level prediction to spatial model resolution

    Science.gov (United States)

    Kowalewski, Marek; Kowalewska-Kalkowska, Halina

    2017-09-01

    The three-dimensional hydrodynamic model of the Baltic Sea (M3D) and its new parallel version (PM3D), developed at the Institute of Oceanography, University of Gdańsk in Poland, was tested to establish a grid resolution adequate for the Baltic Sea level prediction. Four outputs of the M3D/PM3D, calculated with spatial resolution varying from 3 NM to 0.5 NM, were validated by comparing the results with hourly sea level readings collected at 9 Baltic gauges in 2010-2015. The spatial resolution of 1 NM applied to the Baltic Sea resulted in a distinct improvement of agreement between the calculated and observed distributions of data. An increase in the resolution to 0.5 NM in the southern Baltic Sea improved the model quality further, as indicated by the lowest variability, the highest correlation and the highest percentage of water level simulations within the range of ± 0.15 m difference relative to readings. The increase in horizontal resolution allowed to improve the fit between the observed water levels and those calculated by the PM3D in the cases of rapid sea level fluctuations, such as those registered in January 2012. The model performed slightly worse for stations with larger ranges of water level oscillations. As parallel calculations were used in the PM3D, the time necessary for computing the simulations was significantly reduced, which allowed to apply the high-resolution grid also to the operational version of the model.

  14. Sea-level rise modeling handbook: Resource guide for coastal land managers, engineers, and scientists

    Science.gov (United States)

    Doyle, Thomas W.; Chivoiu, Bogdan; Enwright, Nicholas M.

    2015-08-24

    Global sea level is rising and may accelerate with continued fossil fuel consumption from industrial and population growth. In 2012, the U.S. Geological Survey conducted more than 30 training and feedback sessions with Federal, State, and nongovernmental organization (NGO) coastal managers and planners across the northern Gulf of Mexico coast to evaluate user needs, potential benefits, current scientific understanding, and utilization of resource aids and modeling tools focused on sea-level rise. In response to the findings from the sessions, this sea-level rise modeling handbook has been designed as a guide to the science and simulation models for understanding the dynamics and impacts of sea-level rise on coastal ecosystems. The review herein of decision-support tools and predictive models was compiled from the training sessions, from online research, and from publications. The purpose of this guide is to describe and categorize the suite of data, methods, and models and their design, structure, and application for hindcasting and forecasting the potential impacts of sea-level rise in coastal ecosystems. The data and models cover a broad spectrum of disciplines involving different designs and scales of spatial and temporal complexity for predicting environmental change and ecosystem response. These data and models have not heretofore been synthesized, nor have appraisals been made of their utility or limitations. Some models are demonstration tools for non-experts, whereas others require more expert capacity to apply for any given park, refuge, or regional application. A simplified tabular context has been developed to list and contrast a host of decision-support tools and models from the ecological, geological, and hydrological perspectives. Criteria were established to distinguish the source, scale, and quality of information input and geographic datasets; physical and biological constraints and relations; datum characteristics of water and land components

  15. Modeling Coastal Erosion, Passive Inundation, and Dynamic Wave Inundation under Higher Sea Level in Hawaii

    Science.gov (United States)

    Anderson, T. R.

    2015-12-01

    Hawaii State legislators recently formed the Interagency Committee on Climate Adaptation to investigate community vulnerability to sea level rise. We developed modeling to provide the committee with assessments of exposure to coastal erosion, wave inundation, and passive flooding based on the IPCC RCP 8.5 model of sea level rise over the 21st Century. We model the exposure to coastal erosion using a hybrid equilibrium profile model (Anderson et al., 2015) that combines historical rates of shoreline change with a Bruun-type model of beach profile translation. Results are mapped in a GIS showing the 80th percentile probability of potential erosion at years 2030, 2050, 2075, and 2100. Wave inundation is modeled using XBeach. We use a 3 m significant wave height to represent a seasonal high swell event. A separate simulation was run for each heightened sea level (corresponding to the years previously mentioned); which accounts for changes in wave dynamics due to the change in water level over the reef platform. We use a bare earth topo/bathy LiDAR DEM derived from data collected during the 2013 JBLTX survey of the Hawaiian Islands. XBeach modeling is done along one-dimensional profiles spaced 20 m apart. From this, we develop a gridded product of water depth and velocity for use in a vulnerability analysis. Passive inundation due to sea level rise, the so-called "bath tub" method, provide estimates of storm drain flooding and groundwater inundation. Our analysis of these three impacts of sea level rise, combined - coastal erosion, wave inundation, and passive flooding - are used with other available data in the FEMA Hazus software to estimate exposure and loss of upland assets.

  16. Bayesian methods for model uncertainty analysis with application to future sea level rise

    Energy Technology Data Exchange (ETDEWEB)

    Patwardhan, A.; Small, M.J. (Carnegie Mellon Univ., Pittsburgh, PA (United States))

    1992-12-01

    This paper addresses the use of data for identifying and characterizing uncertainties in model parameters and predictions. The Bayesian Monte Carlo method is formally presented and elaborated, and applied to the analysis of the uncertainty in a predictive model for global mean sea level change. The method uses observations of output variables, made with an assumed error structure, to determine a posterior distribution of model outputs. This is used to derive a posterior distribution for the model parameters. Results demonstrate the resolution of the uncertainty that is obtained as a result of the Bayesian analysis and also indicate the key contributors to the uncertainty in the sea level rise model. While the technique is illustrated with a simple, preliminary model, the analysis provides an iterative framework for model refinement. The methodology developed in this paper provides a mechanism for the incorporation of ongoing data collection and research in decision-making for problems involving uncertain environmental change.

  17. Modelling the impacts of sea level rise on tidal basin ecomorphodynamics and mangrove habitat evolution

    Science.gov (United States)

    van Maanen, Barend; Coco, Giovanni; Bryan, Karin

    2016-04-01

    The evolution of tidal basins and estuaries in tropical and subtropical regions is often influenced by the presence of mangrove forests. These forests are amongst the most productive environments in the world and provide important ecosystem services. However, these intertidal habitats are also extremely vulnerable and are threatened by climate change impacts such as sea level rise. It is therefore of key importance to improve our understanding of how tidal systems occupied by mangrove vegetation respond to rising water levels. An ecomorphodynamic model was developed that simulates morphological change and mangrove forest evolution as a result of mutual feedbacks between physical and biological processes. The model accounts for the effects of mangrove trees on tidal flow patterns and sediment dynamics. Mangrove growth is in turn controlled by hydrodynamic conditions. Under stable water levels, model results indicate that mangrove trees enhance the initiation and branching of tidal channels, partly because the extra flow resistance in mangrove forests favours flow concentration, and thus sediment erosion in between vegetated areas. The landward expansion of the channels, on the other hand, is reduced. Model simulations including sea level rise suggest that mangroves can potentially enhance the ability of the soil surface to maintain an elevation within the upper portion of the intertidal zone. While the sea level is rising, mangroves are migrating landward and the channel network tends to expand landward too. The presence of mangrove trees, however, was found to hinder both the branching and headward erosion of the landward expanding channels. Simulations are performed according to different sea level rise scenarios and with different tidal range conditions to assess which tidal environments are most vulnerable. Changes in the properties of the tidal channel networks are being examined as well. Overall, model results highlight the role of mangroves in driving the

  18. Modeling sea level changes and geodetic variations by glacial isostasy: the improved SELEN code

    CERN Document Server

    Spada, Giorgio; Galassi, Gaia; Colleoni, Florence

    2012-01-01

    We describe the basic features of SELEN, an open source Fortran 90 program for the numerical solution of the so-called "Sea Level Equation" for a spherical, layered, non-rotating Earth with Maxwell viscoelastic rheology. The Sea Level Equation was introduced in the 70s to model the sea level variations in response to the melting of late-Pleistocene ice-sheets, but it can be also employed for predictions of geodetic quantities such as vertical and horizontal surface displacements and gravity variations on a global and a regional scale. SELEN (acronym of SEa Level EquatioN solver) is particularly oriented to scientists at their first approach to the glacial isostatic adjustment problem and, according to our experience, it can be successfully used in teaching. The current release (2.9) considerably improves the previous versions of the code in terms of computational efficiency, portability and versatility. In this paper we describe the essentials of the theory behind the Sea Level Equation, the purposes of SELEN...

  19. Modeling Abrupt Change in Global Sea Level Arising from Ocean - Ice-Sheet Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Holland, David M

    2011-09-24

    It is proposed to develop, validate, and apply a coupled ocean ice-sheet model to simulate possible, abrupt future change in global sea level. This research is to be carried out collaboratively between an academic institute and a Department of Energy Laboratory (DOE), namely, the PI and a graduate student at New York University (NYU) and climate model researchers at the Los Alamos National Laboratory (LANL). The NYU contribution is mainly in the area of incorporating new physical processes into the model, while the LANL efforts are focused on improved numerics and overall model development. NYU and LANL will work together on applying the model to a variety of modeling scenarios of recent past and possible near-future abrupt change to the configuration of the periphery of the major ice sheets. The project's ultimate goal is to provide a robust, accurate prediction of future global sea level change, a feat that no fully-coupled climate model is currently capable of producing. This proposal seeks to advance that ultimate goal by developing, validating, and applying a regional model that can simulate the detailed processes involved in sea-level change due to ocean ice-sheet interaction. Directly modeling ocean ice-sheet processes in a fully-coupled global climate model is not a feasible activity at present given the near-complete absence of development of any such causal mechanism in these models to date.

  20. A Bayesian Hierarchical Model for Reconstructing Sea Levels: From Raw Data to Rates of Change

    CERN Document Server

    Cahill, Niamh; Horton, Benjamin P; Parnell, Andrew C

    2015-01-01

    We present a holistic Bayesian hierarchical model for reconstructing the continuous and dynamic evolution of relative sea-level (RSL) change with fully quantified uncertainty. The reconstruction is produced from biological (foraminifera) and geochemical ({\\delta}13C) sea-level indicators preserved in dated cores of salt-marsh sediment. Our model is comprised of three modules: (1) A Bayesian transfer function for the calibration of foraminifera into tidal elevation, which is flexible enough to formally accommodate additional proxies (in this case bulk-sediment {\\delta}13C values); (2) A chronology developed from an existing Bchron age-depth model, and (3) An existing errors-in-variables integrated Gaussian process (EIV-IGP) model for estimating rates of sea-level change. We illustrate our approach using a case study of Common Era sea-level variability from New Jersey, U.S.A. We develop a new Bayesian transfer function (B-TF), with and without the {\\delta}13C proxy and compare our results to those from a widely...

  1. A Bayesian hierarchical model for reconstructing relative sea level: from raw data to rates of change

    Science.gov (United States)

    Cahill, Niamh; Kemp, Andrew C.; Horton, Benjamin P.; Parnell, Andrew C.

    2016-02-01

    We present a Bayesian hierarchical model for reconstructing the continuous and dynamic evolution of relative sea-level (RSL) change with quantified uncertainty. The reconstruction is produced from biological (foraminifera) and geochemical (δ13C) sea-level indicators preserved in dated cores of salt-marsh sediment. Our model is comprised of three modules: (1) a new Bayesian transfer (B-TF) function for the calibration of biological indicators into tidal elevation, which is flexible enough to formally accommodate additional proxies; (2) an existing chronology developed using the Bchron age-depth model, and (3) an existing Errors-In-Variables integrated Gaussian process (EIV-IGP) model for estimating rates of sea-level change. Our approach is illustrated using a case study of Common Era sea-level variability from New Jersey, USA We develop a new B-TF using foraminifera, with and without the additional (δ13C) proxy and compare our results to those from a widely used weighted-averaging transfer function (WA-TF). The formal incorporation of a second proxy into the B-TF model results in smaller vertical uncertainties and improved accuracy for reconstructed RSL. The vertical uncertainty from the multi-proxy B-TF is ˜ 28 % smaller on average compared to the WA-TF. When evaluated against historic tide-gauge measurements, the multi-proxy B-TF most accurately reconstructs the RSL changes observed in the instrumental record (mean square error = 0.003 m2). The Bayesian hierarchical model provides a single, unifying framework for reconstructing and analyzing sea-level change through time. This approach is suitable for reconstructing other paleoenvironmental variables (e.g., temperature) using biological proxies.

  2. Testing the feasability of sea-level reconstructions using SEALEX, a spreadsheet based reef growth model

    Science.gov (United States)

    Koelling, M.

    2009-12-01

    SEALEX, a simple reef growth model (Koelling et al. 2009) has been used to test the feasability of different sea-level reconstructions. The forward model is driven by a user definable sea-level curve. Other adjustable model parameters include maximum coral growth rate, coral growth rate depth dependence and light attenuation, subaerial erosion and subsidence. A time lag for the establishment of significant reef accretion may also be set. During the model run, both, the external shape and the internal chronologic structure of the growing reef as well as the paleo-water-depths are continuously displayed and recorded. The effects of driving the reef growth model with different sea-level reconstructions such as those of Lambeck & Chappell (Science, 2001), Waelbroeck et al (QSR,2002), Siddall et al (nature,2003) and Bintanja et al (nature,2005) for different tectonic settings such as both on slowly subsiding islands like Tahiti (subsidence rates of 0.25 m ka-1) and rapidly subsiding islands like Hawaii (subsidence rate of 2.5 mka-1) as well as rapidly uplifting coastal settings like Huon Peninsula (uplift rates of 0.5 to 4 m ka-1). The model runs show the sensitivity of the resulting overall morphology and internal age structure to the sea level reconstruction used to drive the model.These results can then be compared to observed data allowing different hypothesis concerning reef development to be tested. The model may also be used to assist in finding sampling locations in reef bodies that are likely to contain critical information for sea level studies. Model run of a Huon Peninsula-type reef driven by a spliced sea level curve (200 ka-120 ka:Waelbroeck et al., 2002,120 ka to present: Lambeck and Chappell, 2001 as shown in the inset) and an uplift rate of 2.8 mka-1. For comparison the idealized Huon Peninsula profile is inset together with terrace ages compiled from a Esat et al., 1999, Stein et al., 1993, b Potter et al. (2004), c Chappell et al. (1996) and d

  3. A model to constrain 21st Century sea level rise from tidewater glaciers

    Science.gov (United States)

    Ultee, E.; Bassis, J. N.

    2016-12-01

    Tidewater glaciers are large contributors to global mean sea level rise, both in their own right (e.g. Columbia Glacier, Alaska) and as outlets of the continental ice sheets. Tidewater glaciers are channeled through narrow fjords ( 100-101 km) that are difficult to resolve in continental-scale ice sheet models, hindering sea level rise projections. Moreover, tidewater glaciers respond to difficult-to-resolve local variables, such as precipitation rate and ocean forcing. Here we present a "flowline" model for networks of tidewater glaciers based on Nye's perfect plastic approximation, and we describe how it can be applied to generate constraints on the glaciological contribution to 21st Century sea level rise. The model can be forced with modeled or observed surface mass balance, or coupled with an ice sheet model upstream. Several test cases from Alaska and Greenland demonstrate our model's performance, and we illustrate how adjustments to the sole model parameter can constrain the decade- to century-scale ice flux to the ocean.

  4. 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.

  5. Testing empirical relationships between global sea-level and global temperature in long climate model simulations

    Science.gov (United States)

    von Storch, H.; Zorita, E.; Gonzalez-Rouco, F.

    2009-04-01

    Estimations of future global sea-level rise brought about by increasing concentrations of atmospheric greenhouse gases of anthropogenic origin are based on simulations with coarse-resolution global climate models, which imposes some limitations on the skill of future projections because some of the processes that modulate the heat and fresh water flux into may not be adequately represented. To fill this gap, and until more complex climate models are available, some ad-hoc methods have been proposed that link the rise in global average temperature with the global mean sea-level rise. The statistical methods can be calibrated with observations and applied to the future global temperature rise simulated by climate models. This methods can be tested in the virtual reality simulated by global atmosphere.ocean models. Thereby, deficiencies can be identified and improvement suggested. The output of 1000-year long climate model simulation with the coupled atmosphere-ocean model ECHO-G over the past millennium has been used to determine the skill of different predictors to describe the variations of the rate of sea-level change in the simulation. These predictor variables comprise the global mean near-surface temperature, its rate of change with time and the heat-flux into the ocean. It is found that, in the framework of this climate simulation, global mean temperature is not a good predictor for the rate-of-change of sea-level. The correlation between both variables is not stable along the simulations and even its sign changes. A better predictor is the rate-of-change of temperature. Its correlation with the rate-of-change of sea-level is much more stable, it is always positive along the simulation, and there exists a lead-lag relationship between both that can be understood in simple physical terms. The best predictor among those tested is the heat-flux into the ocean. Its correlation is higher and there exists no time lag to the rate-of-change of sea-level, as expected

  6. Modeling barrier island response to sea-level rise in the outer Banks, North Carolina

    Science.gov (United States)

    Moore, Laura J.; List, Jeffrey H.; Williams, S. Jeffress; Stolper, David

    2007-01-01

    An 8500-year Holocene simulation developed in GEOMBEST provides a possible scenario to explain the evolution of barrier coast between Rodanthe and Cape Hatteras, NC. Sensitivity analyses suggest that in the Outer Banks, the rate of sea-level rise is the most important factor in determining how barrier islands evolve. The Holocene simulation provides a basis for future simulations, which suggest that if sea level rises up to 0.88 m by AD 2100, as predicted by the highest estimates of the Intergovernmental Panel on Climate Change, the barrier in the study area may migrate on the order of 2.5 times more rapidly than at present. If sea level rises beyond IPCC predictions to reach 1.4–1.9 m above modern sea level by AD 2100, model results suggest that barrier islands in the Outer Banks may become vulnerable to threshold collapse, disintegrating during storm events, by the end of the next century. Consistent with sensitivity analyses, additional simulations indicate that anthropogenic activities, such as increasing the rate of sediment supply through beach nourishment, will only slightly affect barrier island migration rates and barrier island vulnerability to collapse.

  7. Uncertainty Assessment for Numerical Modeling of Dune and Backshore Evolution Under Sea-Level Rise Scenarios

    Science.gov (United States)

    Dai, H.; Ye, M.; Niedoroda, A. W.; Kish, S.; Donoghue, J. F.; Saha, B.

    2010-12-01

    The beach dunes play an essential role in the evolution of barrier island shapes and coastlines. The dunes protect the beaches and beach ecology by absorbing energy from the storms and provide sediment to the beaches or backshores when erosion occurs. While a number of models have been developed to simulate the evolution of dunes and backshores, few of the models have comprehensively addressed dune growth, dune erosion, and backshore changes. Based on the assumption that dune shapes are stationary, we develop a new model that can estimate the dune and backshore evolution (including both growth and erosion) under the influence of storms with different sea-level rise scenarios. The modeling results are inherently uncertain due to unknown storm variability and sea-level rise scenarios. The storm uncertainty, characterized as parametric uncertainty, and its propagation to the modeling results are assessed using the Monte Carlo (MC) method. A total of 1500 realizations of storm magnitude, frequency, and track through a barrier island are generated and used for the MC simulation. The numerical modeling and uncertainty analysis is conducted for a synthetic barrier island with physical features and hurrucane exposure similar to Santa Rosa Island, in northwest Florida. Uncertainty in the simulated beach dune heights, dune width, and the backshore positions is assessed for five sea-level rise scenarios. The parametric uncertainty is different for different sea-level rise scenarios. For a given scenario, uncertainty of dune height is the largest and it is mainly caused by uncertainty in storm magnitude. This uncertainty analysis provides guidelines for coastal management and protection of coastal ecology.

  8. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

    OpenAIRE

    Roshan GholamReza; Moghbel Masumeh; Grab Stefan

    2012-01-01

    Abstract The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels...

  9. A benchmark study of the sea-level equation in GIA modelling

    Science.gov (United States)

    Martinec, Zdenek; Klemann, Volker; van der Wal, Wouter; Riva, Riccardo; Spada, Giorgio; Simon, Karen; Blank, Bas; Sun, Yu; Melini, Daniele; James, Tom; Bradley, Sarah

    2017-04-01

    The sea-level load in glacial isostatic adjustment (GIA) is described by the so called sea-level equation (SLE), which represents the mass redistribution between ice sheets and oceans on a deforming earth. Various levels of complexity of SLE have been proposed in the past, ranging from a simple mean global sea level (the so-called eustatic sea level) to the load with a deforming ocean bottom, migrating coastlines and a changing shape of the geoid. Several approaches to solve the SLE have been derived, from purely analytical formulations to fully numerical methods. Despite various teams independently investigating GIA, there has been no systematic intercomparison amongst the solvers through which the methods may be validated. The goal of this paper is to present a series of benchmark experiments designed for testing and comparing numerical implementations of the SLE. Our approach starts with simple load cases even though the benchmark will not result in GIA predictions for a realistic loading scenario. In the longer term we aim for a benchmark with a realistic loading scenario, and also for benchmark solutions with rotational feedback. The current benchmark uses an earth model for which Love numbers have been computed and benchmarked in Spada et al (2011). In spite of the significant differences in the numerical methods employed, the test computations performed so far show a satisfactory agreement between the results provided by the participants. The differences found can often be attributed to the different approximations inherent to the various algorithms. Literature G. Spada, V. R. Barletta, V. Klemann, R. E. M. Riva, Z. Martinec, P. Gasperini, B. Lund, D. Wolf, L. L. A. Vermeersen, and M. A. King, 2011. A benchmark study for glacial isostatic adjustment codes. Geophys. J. Int. 185: 106-132 doi:10.1111/j.1365-

  10. Sea Level Variability During the 1993-1999 Estimated by Assimilating TOPEX/POSEIDON Data Into a General Circulation Model

    Science.gov (United States)

    Staneva, J.; Schroeter, J.; Wenzel, M.

    2001-12-01

    Sea surface height variability is analyzed from ocean model simulations and altimer data. The estimate of the ocean state is obtained by constraining the LSG model of the Max Plank Institute of Meteorology, Hamburg. Seven years (1993-1999) TOPEX/POSEIDON (T/P) sea surface heights relative to the EGM96 geoid model are assimilated into the model. 4D-VAR is used to optimize a set of control variables. The impact of the geoid data is presented by comparing the variability of the simulated sea level, ocean transport of heat and freshwater from two seven-year experiments in which we assimilate either T/P sea level height relative to EGM96 geoid or the sea level temporal anomaly only, provided by T/P.

  11. Uncertainties in Tidally Adjusted Estimates of Sea Level Rise Flooding (Bathtub Model for the Greater London

    Directory of Open Access Journals (Sweden)

    Ali P. Yunus

    2016-04-01

    Full Text Available Sea-level rise (SLR from global warming may have severe consequences for coastal cities, particularly when combined with predicted increases in the strength of tidal surges. Predicting the regional impact of SLR flooding is strongly dependent on the modelling approach and accuracy of topographic data. Here, the areas under risk of sea water flooding for London boroughs were quantified based on the projected SLR scenarios reported in Intergovernmental Panel on Climate Change (IPCC fifth assessment report (AR5 and UK climatic projections 2009 (UKCP09 using a tidally-adjusted bathtub modelling approach. Medium- to very high-resolution digital elevation models (DEMs are used to evaluate inundation extents as well as uncertainties. Depending on the SLR scenario and DEMs used, it is estimated that 3%–8% of the area of Greater London could be inundated by 2100. The boroughs with the largest areas at risk of flooding are Newham, Southwark, and Greenwich. The differences in inundation areas estimated from a digital terrain model and a digital surface model are much greater than the root mean square error differences observed between the two data types, which may be attributed to processing levels. Flood models from SRTM data underestimate the inundation extent, so their results may not be reliable for constructing flood risk maps. This analysis provides a broad-scale estimate of the potential consequences of SLR and uncertainties in the DEM-based bathtub type flood inundation modelling for London boroughs.

  12. Improving GNSS-R sea level determination through inverse modeling of SNR data

    Science.gov (United States)

    Strandberg, Joakim; Hobiger, Thomas; Haas, Rüdiger

    2016-08-01

    This paper presents a new method for retrieving sea surface heights from Global Navigation Satellite Systems reflectometry (GNSS-R) data by inverse modeling of SNR observations from a single geodetic receiver. The method relies on a B-spline representation of the temporal sea level variations in order to account for its continuity. The corresponding B-spline coefficients are determined through a nonlinear least squares fit to the SNR data, and a consistent choice of model parameters enables the combination of multiple GNSS in a single inversion process. This leads to a clear increase in precision of the sea level retrievals which can be attributed to a better spatial and temporal sampling of the reflecting surface. Tests with data from two different coastal GNSS sites and comparison with colocated tide gauges show a significant increase in precision when compared to previously used methods, reaching standard deviations of 1.4 cm at Onsala, Sweden, and 3.1 cm at Spring Bay, Tasmania.

  13. Dynamics of sea level variations in the coastal Red Sea

    Science.gov (United States)

    Churchill, James; Abulnaja, Yasser; Nellayaputhenpeedika, Mohammedali; Limeburner, Richard; Lentz, Steven

    2016-04-01

    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. While considerable scientific work has been directed at tidal and seasonal variations of Red Sea water level, very little attention has been given to elevation changes in an 'intermediate' frequency band, with periods of 2-30 d, even though motions in this band account for roughly half of the sea level variance in central Red Sea. We examined the sea level signal in this band using AVISO sea level anomaly (SLA) data, COARDAS wind data and measurements from pressure sensors maintained for more than five years at a number of locations in Saudi Arabian coastal waters. Empirical orthogonal function analysis of the SLA data indicates that longer-period (10-30 d) sea level variations in the intermediate band are dominated by coherent motions in a single mode that extends over most of the Red Sea axis. Idealized model results indicate that this large-scale mode of sea level motion is principally due to variations in the large-scale gradient of the along-axis wind. Our analysis indicates that coastal sea level motions at shorter periods (2-10 d) are principally generated by a combination of direct forcing by the local wind stress and forcing associated with large-scale wind stress gradients. However, also contributing to coastal sea level variations in the intermediate frequency band are mesoscale eddies, which are prevalent throughout the Red Sea basin, have a sea level signal of 10's of cm and produce relatively small-scale (order 50 km) changes in coastal sea level.

  14. A new hybrid model for filling gaps and forecast in sea level: application to the eastern English Channel and the North Atlantic Sea (western France)

    Science.gov (United States)

    Turki, Imen; Laignel, Benoit; Kakeh, Nabil; Chevalier, Laetitia; Costa, Stephane

    2015-04-01

    This research is carried out in the framework of the program Surface Water and Ocean Topography (SWOT) which is a partnership between NASA and CNES. Here, a new hybrid model is implemented for filling gaps and forecasting the hourly sea level variability by combining classical harmonic analyses to high statistical methods to reproduce the deterministic and stochastic processes, respectively. After simulating the mean trend sea level and astronomical tides, the nontidal residual surges are investigated using an autoregressive moving average (ARMA) methods by two ways: (1) applying a purely statistical approach and (2) introducing the SLP in ARMA as a main physical process driving the residual sea level. The new hybrid model is applied to the western Atlantic sea and the eastern English Channel. Using ARMA model and considering the SLP, results show that the hourly sea level observations of gauges with are well reproduced with a root mean square error (RMSE) ranging between 4.5 and 7 cm for 1 to 30 days of gaps and an explained variance more than 80 %. For larger gaps of months, the RMSE reaches 9 cm. The negative and the positive extreme values of sea levels are also well reproduced with a mean explained variance between 70 and 85 %. The statistical behavior of 1-year modeled residual components shows good agreements with observations. The frequency analysis using the discrete wavelet transform illustrate strong correlations between observed and modeled energy spectrum and the bands of variability. Accordingly, the proposed model presents a coherent, simple, and easy tool to estimate the total sea level at timescales from days to months. The ARMA model seems to be more promising for filling gaps and estimating the sea level at larger scales of years by introducing more physical processes driving its stochastic variability.

  15. Application of the Sea-Level Affecting Marshes Model (SLAMM 5.0) to Cabo Rojo and Laguna Cartagena National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Sea-Level Affecting Marshes Model (SLAMM) report presents a model for projecting the effects of sea-level rise on coastal marshes and related habitats on Cabo...

  16. A fully coupled 3-D ice-sheet–sea-level model: algorithm and applications

    NARCIS (Netherlands)

    De Boer, B.; Stocchi, P.; van de Wal, R.S.W.

    2014-01-01

    Relative sea-level variations during the late Pleistocene can only be reconstructed with the knowledge of ice-sheet history. On the other hand, the knowledge of regional and global relative sea-level variations is necessary to learn about the changes in ice volume. Overcoming this problem of

  17. A fully coupled 3-D ice-sheet-sea-level model : Algorithm and applications

    NARCIS (Netherlands)

    De Boer, B.; Stocchi, P.; Van De Wal, R. S W

    2014-01-01

    Relative sea-level variations during the late Pleistocene can only be reconstructed with the knowledge of ice-sheet history. On the other hand, the knowledge of regional and global relative sea-level variations is necessary to learn about the changes in ice volume. Overcoming this problem of

  18. Modeling and Analysis of Sea-level Rise Impacts on Salinity in the Lower St. Johns River

    Science.gov (United States)

    Bacopoulos, P.

    2015-12-01

    There is deliberate attention being paid to studying sea-level rise impacts on the lower St. Johns River, a drowned coastal plain-type estuary with low topographic drive, located in northeastern Florida. One area of attention is salinity in the river, which influences the entire food web, including sea and marsh grasses, juvenile crustaceans and fishes, wading birds and migratory waterfowl, marine mammals and other predator animals. It is expected that elevated ocean levels will increase the salinity of the estuarine waters, leading to deleterious effects on dependent species of the river biology. The objective of the modeling and analysis was: 1) to establish baseline conditions of salinity for the lower St. Johns River; and 2) to examine future conditions of salinity, as impacted by sea-level rise. Establishing baseline conditions entailed validation of the model for present-day salinity in the lower St. Johns River via comparison to available data. Examining future conditions entailed application of the model for sea-level rise scenarios, with comparison to the baseline conditions, for evaluation of sea-level rise impacts on salinity. While the central focus was on the physics of sea-level rise impacts on salinity, some level of salinity-biological assessment was conducted to identify sea-level rise/salinity thresholds, as related to negatively impacting different species of the river biology.

  19. Hydroclimatic modelling of local sea level rise and its projection in future

    Science.gov (United States)

    Naren, A.; Maity, Rajib

    2016-09-01

    Studies on sea level rise (SLR) in the context of climate change are gaining importance in the recent past. Whereas there is some clear evidence of SLR at global scale, its trend varies significantly from location to location. The role of different meteorological variables on sea level change (SLC) is explored. We hypothesise that the role of such variables varies from location to location and modelling of local SLC requires a proper identification of specific role of individual factors. After identifying a group of various local meteorological variables, Supervised Principal Component Analysis (SPCA) is used to develop a location specific Combined Index (CI). The SPCA ensures that the developed CI possesses highest possible association with the historical SLC at that location. Further, using the developed CI, an attempt is made to model the local sea level (LSL) variation in synchronous with the changing climate. The developed approach, termed as hydroclimatic semi-empirical approach, is found to be potential for local SLC at different coastal locations. The validated hydroclimatic approach is used for future projection of SLC at those coastal locations till 2100 for different climate change scenarios, i.e. different Representative Concentration Pathways (RCPs). Future hydrometeorological variables are obtained from Global Climate Models (GCMs) for different such scenarios, i.e. RCP2.6, RCP4.5 and RCP8.5. Effect of glacial isostatic readjustment (GIA) is not included in this study. However, if the reliable information on GIA is available for a location, the same can be arithmetically added to the final outcome of the proposed hydrometeorological approach.

  20. Last deglacial relative sea level variations in Antarctica derived from glacial isostatic adjustment modelling

    Directory of Open Access Journals (Sweden)

    Jun'ichi Okuno

    2013-11-01

    Full Text Available We present relative sea level (RSL curves in Antarctica derived from glacial isostatic adjustment (GIA predictions based on the melting scenarios of the Antarctic ice sheet since the Last Glacial Maximum (LGM given in previous works. Simultaneously, Holocene-age RSL observations obtained at the raised beaches along the coast of Antarctica are shown to be in agreement with the GIA predictions. The differences from previously published ice-loading models regarding the spatial distribution and total mass change of the melted ice are significant. These models were also derived from GIA modelling; the variations can be attributed to the lack of geological and geographical evidence regarding the history of crustal movement due to ice sheet evolution. Next, we summarise the previously published ice load models and demonstrate the RSL curves based on combinations of different ice and earth models. The RSL curves calculated by GIA models indicate that the model dependence of both the ice and earth models is significantly large at several sites where RSL observations were obtained. In particular, GIA predictions based on the thin lithospheric thickness show the spatial distributions that are dependent on the melted ice thickness at each sites. These characteristics result from the short-wavelength deformation of the Earth. However, our predictions strongly suggest that it is possible to find the average ice model despite the use of the different models of lithospheric thickness. By sea level and crustal movement observations, we can deduce the geometry of the post-LGM ice sheets in detail and remove the GIA contribution from the crustal deformation and gravity change observed by space geodetic techniques, such as GPS and GRACE, for the estimation of the Antarctic ice mass change associated with recent global warming.

  1. Prediction of altimetric sea level anomalies using time series models based on spatial correlation

    Science.gov (United States)

    Miziński, Bartłomiej; Niedzielski, Tomasz

    2014-05-01

    Sea level anomaly (SLA) times series, which are time-varying gridded data, can be modelled and predicted using time series methods. This approach has been shown to provide accurate forecasts within the Prognocean system, the novel infrastructure for anticipating sea level change designed and built at the University of Wrocław (Poland) which utilizes the real-time SLA data from Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO). The system runs a few models concurrently, and our ocean prediction experiment includes both uni- and multivariate time series methods. The univariate ones are: extrapolation of polynomial-harmonic model (PH), extrapolation of polynomial-harmonic model and autoregressive prediction (PH+AR), extrapolation of polynomial-harmonic model and self-exciting threshold autoregressive prediction (PH+SETAR). The following multivariate methods are used: extrapolation of polynomial-harmonic model and vector autoregressive prediction (PH+VAR), extrapolation of polynomial-harmonic model and generalized space-time autoregressive prediction (PH+GSTAR). As the aforementioned models and the corresponding forecasts are computed in real time, hence independently and in the same computational setting, we are allowed to compare the accuracies offered by the models. The objective of this work is to verify the hypothesis that the multivariate prediction techniques, which make use of cross-correlation and spatial correlation, perform better than the univariate ones. The analysis is based on the daily-fitted and updated time series models predicting the SLA data (lead time of two weeks) over several months when El Niño/Southern Oscillation (ENSO) was in its neutral state.

  2. Detailed Flood Modeling and Hazard Assessment from Storm Tides, Rainfall and Sea Level Rise

    Science.gov (United States)

    Orton, P. M.; Hall, T. M.; Georgas, N.; Conticello, F.; Cioffi, F.; Lall, U.; Vinogradov, S. V.; Blumberg, A. F.

    2014-12-01

    A flood hazard assessment has been conducted for the Hudson River from New York City to Troy at the head of tide, using a three-dimensional hydrodynamic model and merging hydrologic inputs and storm tides from tropical and extra-tropical cyclones, as well as spring freshet floods. Our recent work showed that neglecting freshwater flows leads to underestimation of peak water levels at up-river sites and neglecting stratification (typical with two-dimensional modeling) leads to underestimation all along the Hudson. The hazard assessment framework utilizes a representative climatology of over 1000 synthetic tropical cyclones (TCs) derived from a statistical-stochastic TC model, and historical extra-tropical cyclones and freshets from 1950-present. Hydrodynamic modeling is applied with seasonal variations in mean sea level and ocean and estuary stratification. The model is the Stevens ECOM model and is separately used for operational ocean forecasts on the NYHOPS domain (http://stevens.edu/NYHOPS). For the synthetic TCs, an Artificial Neural Network/ Bayesian multivariate approach is used for rainfall-driven freshwater inputs to the Hudson, translating the TC attributes (e.g. track, SST, wind speed) directly into tributary stream flows (see separate presentation by Cioffi for details). Rainfall intensity has been rising in recent decades in this region, and here we will also examine the sensitivity of Hudson flooding to future climate warming-driven increases in storm precipitation. The hazard assessment is being repeated for several values of sea level, as projected for future decades by the New York City Panel on Climate Change. Recent studies have given widely varying estimates of the present-day 100-year flood at New York City, from 2.0 m to 3.5 m, and special emphasis will be placed on quantifying our study's uncertainty.

  3. Incorporating sediment compaction into a gravitationally self-consistent model for ice age sea-level change

    Science.gov (United States)

    Ferrier, Ken L.; Austermann, Jacqueline; Mitrovica, Jerry X.; Pico, Tamara

    2017-10-01

    Sea-level changes are of wide interest because they regulate coastal hazards, shape the sedimentary geologic record and are sensitive to climate change. In areas where rivers deliver sediment to marine deltas and fans, sea-level changes are strongly modulated by the deposition and compaction of marine sediment. Deposition affects sea level by increasing the elevation of the seafloor, by perturbing crustal elevation and gravity fields and by reducing the volume of seawater through the incorporation of water into sedimentary pore space. In a similar manner, compaction affects sea level by lowering the elevation of the seafloor and by purging water out of sediments and into the ocean. Here we incorporate the effects of sediment compaction into a gravitationally self-consistent global sea-level model by extending the approach of Dalca et al. (2013). We show that incorporating compaction requires accounting for two quantities that are not included in the Dalca et al. (2013) analysis: the mean porosity of the sediment and the degree of saturation in the sediment. We demonstrate the effects of compaction by modelling sea-level responses to two simplified 122-kyr sediment transfer scenarios for the Amazon River system, one including compaction and one neglecting compaction. These simulations show that the largest effect of compaction is on the thickness of the compacting sediment, an effect that is largest where deposition rates are fastest. Compaction can also produce minor sea-level changes in coastal regions by influencing shoreline migration and the location of seawater loading, which perturbs crustal elevations. By providing a tool for modelling gravitationally self-consistent sea-level responses to sediment compaction, this work offers an improved approach for interpreting the drivers of past sea-level changes.

  4. Remote Sensing of Vegetation Parameters for Modeling Coastal Marsh Response to Sea Level Rise

    Science.gov (United States)

    Byrd, K. B.; Windham-Myers, L.; Warzecha, B.; Crowe, R.; Vasey, M. C.; Ferner, M.

    2014-12-01

    Coastal planners are seeking ways to prepare for the potential impacts of future climate change, particularly sea level rise though management of future risks is complicated by uncertainty in the timing, distribution and extent of these impacts. Sea level rise impacts will be most evident at the regional level where decisions related to climate change adaptation including those related to land use planning and habitat management typically occur. To aid coastal managers with decision-making we are integrating remote sensing data with the marsh equilibrium model (MEM3) to project coastal marsh habitat response to future sea level rise. MEM3 is a 1-dimentional, calibrated Excel-based model that incorporates both physical and biological feedbacks to changing relative elevations. Modeled future elevations are then distributed at the regional scale with LiDAR DEMs to project changes to coastal habitats and dependent wildlife. Because plant biomass and structure influence both organic and inorganic accretion, MEM3 includes multiple vegetation input variables. Deriving these variables, including maximum and minimum elevations of marsh vegetation, peak aboveground biomass, and elevation at peak biomass from remote sensing will enable the model to have spatially variable inputs across sites. We are evaluating 30m Landsat 8 and 2m World View-2 (WV2) satellite data for mapping peak biomass at Rush Ranch, a highly diverse brackish marsh in the San Francisco Bay National Estuarine Research Reserve. The high spatial resolution of WV2 produces greater variability in plant reflectance at the pixel scale than Landsat 8. Initial results show the need for plant community-specific biomass models with WV2 to account for differences in plant structure and canopy architecture. When removing plots dominated by Salicornia pacifica and Lepidium latifolium, peak biomass is best estimated with an NDVI-type vegetation index based on WV2 near infrared bands 7 and 8 (R2 = 0.21, RMSE = 318 g/m2

  5. National scale multivariate extreme value modelling of waves, winds and sea levels

    Directory of Open Access Journals (Sweden)

    Gouldby Ben

    2016-01-01

    Full Text Available It has long been recognised that extreme coastal flooding can arise from the joint occurrence of extreme waves, winds and sea levels. The standard simplified joint probability approach used in England and Wales can result in an underestimation of flood risk unless correction factors are applied. This paper describes the application of a state-of-the-art multivariate extreme value model to offshore winds, waves and sea levels around the coast of England. The methodology overcomes the limitations of the traditional method. The output of the new statistical analysis is a Monte-Carlo (MC simulation comprising many thousands of offshore extreme events and it is necessary to translate all of these events into overtopping rates for use as input to flood risk assessments. It is computationally impractical to transform all of these MC events from the offshore to the nearshore. Computationally efficient statistical emulators of the SWAN wave transformation model have therefore been constructed. The emulators translate the thousands of MC events offshore. Whilst the methodology has been applied for national flood risk assessment, it has the potential to be implemented for wider use, including climate change impact assessment, nearshore wave climates for detailed local assessments and coastal flood forecasting.

  6. Coastal Wetland Dynamics and Wildlife Populations: Modeling the Effects of Sea Level Rise and Landscape Change

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Assess the potential impacts of sea level rise on coastal ecosystems and related wildlife resources. Develop a Bayesian Belief network that projects the impact of...

  7. On the Accuracy of Glacial Isostatic Adjustment Models for Geodetic Observations to Estimate Arctic Ocean Sea-Level Change

    Directory of Open Access Journals (Sweden)

    Zhenwei Huang

    2013-01-01

    Full Text Available Arctic Ocean sea-level change is an important indicator of climate change. Contemporary geodetic observations, including data from tide gages, satellite altimetry and Gravity Recovery and Climate Experiment (GRACE, are sensitive to the effect of the ongoing glacial isostatic adjustment (GIA process. To fully exploit these geodetic observations to study climate related sea-level change, this GIA effect has to be removed. However, significant uncertainty exists with regard to the GIA model, and using different GIA models could lead to different results. In this study we use an ensemble of 14 contemporary GIA models to investigate their differences when they are applied to the above-mentioned geodetic observations to estimate sea-level change in the Arctic Ocean. We find that over the Arctic Ocean a large range of differences exists in GIA models when they are used to remove GIA effect from tide gage and GRACE observations, but with a relatively smaller range for satellite altimetry observations. In addition, we compare the derived sea-level trend from observations after applying different GIA models in the study regions, sea-level trend estimated from long-term tide gage data shows good agreement with altimetry result over the same data span. However the mass component of sea-level change obtained from GRACE data does not agree well with the result derived from steric-corrected altimeter observation due primarily to the large uncertainty of GIA models, errors in the Arctic Ocean altimetry or steric measurements, inadequate data span, or all of the above. We conclude that GIA correction is critical for studying sea-level change over the Arctic Ocean and further improvement in GIA modelling is needed to reduce the current discrepancies among models.

  8. A model study of factors influencing projected changes in regional sea level over the twenty-first century

    Energy Technology Data Exchange (ETDEWEB)

    Pardaens, Anne K.; Lowe, J.A. [Met Office, Hadley Centre, Exeter, Devon (United Kingdom); Gregory, J.M. [Met Office, Hadley Centre, Exeter, Devon (United Kingdom); University of Reading, Department of Meteorology, Walker Institute for Climate System Research, Earley Gate, PO Box 243, Reading (United Kingdom)

    2011-05-15

    In addition to projected increases in global mean sea level over the 21st century, model simulations suggest there will also be changes in the regional distribution of sea level relative to the global mean. There is a considerable spread in the projected patterns of these changes by current models, as shown by the recent Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (AR4). This spread has not reduced from that given by the Third Assessment models. Comparison with projections by ensembles of models based on a single structure supports an earlier suggestion that models of similar formulation give more similar patterns of sea level change. Analysing an AR4 ensemble of model projections under a business-as-usual scenario shows that steric changes (associated with subsurface ocean density changes) largely dominate the sea level pattern changes. The relative importance of subsurface temperature or salinity changes in contributing to this differs from region to region and, to an extent, from model-to-model. In general, thermosteric changes give the spatial variations in the Southern Ocean, halosteric changes dominate in the Arctic and strong compensation between thermosteric and halosteric changes characterises the Atlantic. The magnitude of sea level and component changes in the Atlantic appear to be linked to the amount of Atlantic meridional overturning circulation (MOC) weakening. When the MOC weakening is substantial, the Atlantic thermosteric patterns of change arise from a dominant role of ocean advective heat flux changes. (orig.)

  9. Modeling caspian sea water level oscilLations Under Diffrent Scenarioes of Increasing Atmospheric Carbon Dioxide Concentrations

    Directory of Open Access Journals (Sweden)

    GholamReza Roshan

    2012-12-01

    Full Text Available The rapid rise of Caspian Sea water level (about 2.25 meters since 1978 has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in thecoastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was stimulated. Variations in environmentalparameters such as temperature, precipitation, evaporation, tmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for bothpast (1951-2006 and future (2025-2100 time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software(version 5.3. The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site has increased by ca. 0.17ºC per decade under the impacts of atmospheric carbon dioxide changes (r=0.21. The Caspian Sea water level has increasedby ca. +36 mm per decade (r=0.82 between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64ºC and precipitation will decrease by ca. 10% (182 mm over the Caspian Sea, whilst in the Volga river basin,temperatures are projected to increase by ca. 4.78ºC and precipitation increase by ca. 12% (58 mm by the year 2100. Finally, statistical modeling of the Caspian Sea water levels projectfuture water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  10. SEA LEVEL (TOPEX/POSEIDON)

    Data.gov (United States)

    National Aeronautics and Space Administration — Sea level rise is caused by the thermal expansion of sea water due to climate warming and widespread melting of land ice. The TOPEX/POSEIDON mission a joint...

  11. Global coastal wetland change under sea-level rise and related stresses: The DIVA Wetland Change Model

    Science.gov (United States)

    Spencer, Thomas; Schuerch, Mark; Nicholls, Robert J.; Hinkel, Jochen; Lincke, Daniel; Vafeidis, A. T.; Reef, Ruth; McFadden, Loraine; Brown, Sally

    2016-04-01

    The Dynamic Interactive Vulnerability Assessment Wetland Change Model (DIVA_WCM) comprises a dataset of contemporary global coastal wetland stocks (estimated at 756 × 103 km2 (in 2011)), mapped to a one-dimensional global database, and a model of the macro-scale controls on wetland response to sea-level rise. Three key drivers of wetland response to sea-level rise are considered: 1) rate of sea-level rise relative to tidal range; 2) lateral accommodation space; and 3) sediment supply. The model is tuned by expert knowledge, parameterised with quantitative data where possible, and validated against mapping associated with two large-scale mangrove and saltmarsh vulnerability studies. It is applied across 12,148 coastal segments (mean length 85 km) to the year 2100. The model provides better-informed macro-scale projections of likely patterns of future coastal wetland losses across a range of sea-level rise scenarios and varying assumptions about the construction of coastal dikes to prevent sea flooding (as dikes limit lateral accommodation space and cause coastal squeeze). With 50 cm of sea-level rise by 2100, the model predicts a loss of 46-59% of global coastal wetland stocks. A global coastal wetland loss of 78% is estimated under high sea-level rise (110 cm by 2100) accompanied by maximum dike construction. The primary driver for high vulnerability of coastal wetlands to sea-level rise is coastal squeeze, a consequence of long-term coastal protection strategies. Under low sea-level rise (29 cm by 2100) losses do not exceed ca. 50% of the total stock, even for the same adverse dike construction assumptions. The model results confirm that the widespread paradigm that wetlands subject to a micro-tidal regime are likely to be more vulnerable to loss than macro-tidal environments. Countering these potential losses will require both climate mitigation (a global response) to minimise sea-level rise and maximisation of accommodation space and sediment supply (a regional

  12. On sea level - ice sheet interactions

    Science.gov (United States)

    Gomez, Natalya Alissa

    This thesis focuses on the physics of static sea-level changes following variations in the distribution of grounded ice and the influence of these changes on the stability and dynamics of marine ice sheets. Gravitational, deformational and rotational effects associated with changes in grounded ice mass lead to markedly non-uniform spatial patterns of sea-level change. I outline a revised theory for computing post-glacial sea-level predictions and discuss the dominant physical effects that contribute to the patterns of sea-level change associated with surface loading on different timescales. I show, in particular, that a large sea-level fall (rise) occurs in the vicinity of a retreating (advancing) ice sheet on both short and long timescales. I also present an application of the sea-level theory in which I predict the sea-level changes associated with a new model of North American ice sheet evolution and consider the implications of the results for efforts to establish the sources of Meltwater Pulse 1A. These results demonstrate that viscous deformational effects can influence the amplitude of sea-level changes observed at far-field sea-level sites, even when the time window being considered is relatively short (≤ 500 years). Subsequently, I investigate the feedback of sea-level changes on marine ice-sheet stability and dynamics by coupling a global sea-level model to ice-sheet models of increasing complexity. To begin, I incorporate gravitationally self-consistent sea-level changes into an equilibrium marine ice-sheet stability theory to show that the sea-level changes have a stabilizing influence on ice-sheet retreat. Next, I consider the impact of the stabilizing mechanism on the timescale of ice-sheet retreat using a 1D dynamic coupled ice sheet - sea level model. Simulations with the coupled model, which incorporate viscoelastic deformation of the solid Earth, show that local sea-level changes at the grounding line act to slow, and in some cases, halt

  13. Reconstructing the contribution of the Weddell Sea sector, Antarctica, to sea level rise since the last glacial maximum, using numerical modelling constrained by field evidence.

    Science.gov (United States)

    Le Brocq, A.; Bentley, M.; Hubbard, A.; Fogwill, C.; Sugden, D.

    2008-12-01

    A numerical ice sheet model constrained by recent field evidence is employed to reconstruct the Last Glacial Maximum (LGM) ice sheet in the Weddell Sea Embayment (WSE). Previous modelling attempts have predicted an extensive grounding line advance (to the continental shelf break) in the WSE, leading to a large equivalent sea level contribution for the sector. The sector has therefore been considered as a potential source for a period of rapid sea level rise (MWP1a, 20 m rise in ~500 years). Recent field evidence suggests that the elevation change in the Ellsworth mountains at the LGM is lower than previously thought (~400 m). The numerical model applied in this paper suggests that a 400 m thicker ice sheet at the LGM does not support such an extensive grounding line advance. A range of ice sheet surfaces, resulting from different grounding line locations, lead to an equivalent sea level estimate of 1 - 3 m for this sector. It is therefore unlikely that the sector made a significant contribution to sea level rise since the LGM, and in particular to MWP1a. The reduced ice sheet size also has implications for the correction of GRACE data, from which Antarctic mass balance calculations have been derived.

  14. Integrated Modeling for the Assessment of Ecological Impacts of Sea Level Rise

    Science.gov (United States)

    Hagen, S. C.; Lewis, G.; Bartel, R.; Batten, B.; Huang, W.; Morris, J.; Slinn, D. N.; Sparks, J.; Walters, L.; Wang, D.; Weishampel, J.; Yeh, G.

    2010-12-01

    Sea level rise (SLR) has the potential to affect a variety of coastal habitats with a myriad of deleterious ecological effects and to overwhelm human settlements along the coast. SLR should be given serious consideration when more than half of the U.S. population lives within 50 miles of the coast. SLR effects will be felt along coastal beaches and in estuarine waters, with consequences to barrier islands, submerged aquatic vegetation beds, sand and mud flats, oyster reefs, and tidal and freshwater wetlands. Managers of these coastal resources must be aware of potential consequences of SLR and adjust their plans accordingly to protect and preserve the resources under their care. The Gulf Coast provides critical habitats for a majority of the commercially important species in the Gulf of Mexico, which depend on inshore waters for either permanent residence or nursery area. The ecosystem services provided by these coastal habitats are at risk from rising sea level. Our team will assess the risk to coasts and coastal habitats from SLR in a 5-year project. We will apply existing models of circulation and transport from the watershed to the sea. The ultimate prediction will be of sediment loadings to the estuary as a result of overland flow, shoreline and barrier island erosion, and salinity transport, all of which will be used to model the evolution of intertidal marshes (MEM II). Over the five-year course of our research we will be simulating hydrodynamics and transport for all three NERRS reserves, including: Apalachicola, Weeks Bay and Grand Bay. The project will result in products whereby managers will be able to assess marshes, oyster reefs, submerged aquatic vegetation, predict wetland stability and indentify restoration locations for marsh and oyster habitats. In addition, we will produce Decision Support tools that will enable managers to predict future coastal erosion rates for management-specified shorelines. Project outcomes will enable the management

  15. Installation and operation manual on sea level gauge (Model: NIO_Ghana_2004)

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A; Pereira, A; VijayKumar, K.; Prabhudesai, S.; Methar, A; Dias, M.

    NIO sea level gauge is a pressure-based gauge that operates on 12 volts battery. The pressure-sensing element used in this gauge is a piezo-resistive programmable semiconductor transducer that provides pressure samples in RS-485 format...

  16. The Blackwater NWR inundation model. Rising sea level on a low-lying coast: land use planning for wetlands

    Science.gov (United States)

    Larsen, Curt; Clark, Inga; Guntenspergen, Glenn; Cahoon, Don; Caruso, Vincent; Hupp, Cliff; Yanosky, Tom

    2004-01-01

    The Blackwater National Wildlife Refuge (BNWR), on the Eastern Shore of Chesapeake Bay (figure 1), occupies an area less than 1 meter above sea level. The Refuge has been featured prominently in studies of the impact of sea level rise on coastal wetlands. Most notably, the refuge has been sited by the Intergovernmental Panel on Climate Change (IPCC) as a key example of 'wetland loss' attributable to rising sea level due to global temperature increase. Comparative studies of aerial photos taken since 1938 show an expanding area of open water in the central area of the refuge. The expanding area of open water can be shown to parallel the record of sea level rise over the past 60 years. The U.S. Fish and Wildlife Service (FWS) manages the refuge to support migratory waterfowl and to preserve endangered upland species. High marsh vegetation is critical to FWS waterfowl management strategies. A broad area once occupied by high marsh has decreased with rising sea level. The FWS needs a planning tool to help predict current and future areas of high marsh available for waterfowl. 'Wetland loss' is a relative term. It is dependant on the boundaries chosen for measurement. Wetland vegetation, zoned by elevation and salinity (figure 3), respond to rising sea level. Wetlands migrate inland and upslope and may vary in areas depending on the adjacent land slopes. Refuge managers need a geospatial tool that allows them to predict future areas that will be converted to high and intertidal marsh. Shifts in location and area of coverage must be anticipated. Viability of a current marsh area is also important. When will sea level rise make short-term management strategies to maintain an area impractical? The USGS has developed an inundation model for the BNWR centered on the refuge and surrounding areas. Such models are simple in concept, but they require a detailed topographic map upon which to superimpose future sea level positions. The new system of LIDAR mapping of land and

  17. 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.

  18. Final project memorandum: sea-level rise modeling handbook: resource guide for resource managers, engineers, and scientists

    Science.gov (United States)

    Doyle, Thomas W.

    2015-01-01

    Coastal wetlands of the Southeastern United States are undergoing retreat and migration from increasing tidal inundation and saltwater intrusion attributed to climate variability and sea-level rise. Much of the literature describing potential sea-level rise projections and modeling predictions are found in peer-reviewed academic journals or government technical reports largely suited to reading by other Ph.D. scientists who are more familiar or engaged in the climate change debate. Various sea-level rise and coastal wetland models have been developed and applied of different designs and scales of spatial and temporal complexity for predicting habitat and environmental change that have not heretofore been synthesized to aid natural resource managers of their utility and limitations. Training sessions were conducted with Federal land managers with U.S. Fish and Wildlife Service, National Park Service, and NOAA National Estuarine Research Reserves as well as state partners and nongovernmental organizations across the northern Gulf Coast from Florida to Texas to educate and to evaluate user needs and understanding of concepts, data, and modeling tools for projecting sea-level rise and its impact on coastal habitats and wildlife. As a result, this handbook was constructed from these training and feedback sessions with coastal managers and biologists of published decision-support tools and simulation models for sea-level rise and climate change assessments. A simplified tabular context was developed listing the various kinds of decision-support tools and ecological models along with criteria to distinguish the source, scale, and quality of information input and geographic data sets, physical and biological constraints and relationships, datum characteristics of water and land elevation components, utility options for setting sea-level rise and climate change scenarios, and ease or difficulty of storing, displaying, or interpreting model output. The handbook is designed

  19. Application of geoprocessing and simulation modeling to estimate impacts of sea level rise on the northeast coast of Florida

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.K.; Park, R.A.; Mausel, P.W. (Indiana Univ., Bloomington (United States) Indiana State Univ., Terre Haute (United States))

    1992-11-01

    Simulation modeling was applied to predict the response of northeast Florida coastal wetlands to future sea level rise due to global warming. Remote sensing and geographic information systems (GIS) were used to develop, manipulate, and synthesize model input including land cover, digital elevation data, and site characteristics data. The SLAMM3 model evaluated the input data to predict responses of coastal wetlands and lowlands to inundation and erosion by sea level rise, and determined transfers from one habitat to another on a cell-by-cell basis. Significant changes were predicted from different scenarios of sea level rise: 0.5 m, 1.0 m, and 1.25 m. The simulations indicated that 31.9 percent and 40.0 percent of wetlands within the study area would be lost with a 1.0 m and 1.25 m sea level rise, respectively, while 6.5 percent would be lost with 0.5 m rise. 45 refs.

  20. Level-Ice Melt Ponds in the Los Alamos Sea Ice Model, CICE

    Science.gov (United States)

    2012-12-06

    physical features such as snow topography and hydraulic meltwater transport rates both laterally and vertically. Departing from the cellular automaton...parameterizations before, or are mod- eled here in a different manner from prior work. When meltwater forms with snow still on the ice, the water is...thickest ice, near Greenland and the Canadian Arctic. A larger fraction of this thicker sea ice is ridged, less level ice is available for ponding, and

  1. Holocene sea-level changes along the North Carolina Coastline and their implications for glacial isostatic adjustment models

    Science.gov (United States)

    Horton, B.P.; Peltier, W.R.; Culver, S.J.; Drummond, R.; Engelhart, S.E.; Kemp, A.C.; Mallinson, D.; Thieler, E.R.; Riggs, S.R.; Ames, D.V.; Thomson, K.H.

    2009-01-01

    We have synthesized new and existing relative sea-level (RSL) data to produce a quality-controlled, spatially comprehensive database from the North Carolina coastline. The RSL database consists of 54 sea-level index points that are quantitatively related to an appropriate tide level and assigned an error estimate, and a further 33 limiting dates that confine the maximum and minimum elevations of RSL. The temporal distribution of the index points is very uneven with only five index points older than 4000 cal a BP, but the form of the Holocene sea-level trend is constrained by both terrestrial and marine limiting dates. The data illustrate RSL rapidly rising during the early and mid Holocene from an observed elevation of -35.7 ?? 1.1 m MSL at 11062-10576 cal a BP to -4.2 m ?? 0.4 m MSL at 4240-3592 cal a BP. We restricted comparisons between observations and predictions from the ICE-5G(VM2) with rotational feedback Glacial Isostatic Adjustment (GIA) model to the Late Holocene RSL (last 4000 cal a BP) because of the wealth of sea-level data during this time interval. The ICE-5G(VM2) model predicts significant spatial variations in RSL across North Carolina, thus we subdivided the observations into two regions. The model forecasts an increase in the rate of sea-level rise in Region 1 (Albemarle, Currituck, Roanoke, Croatan, and northern Pamlico sounds) compared to Region 2 (southern Pamlico, Core and Bogue sounds, and farther south to Wilmington). The observations show Late Holocene sea-level rising at 1.14 ?? 0.03 mm year-1 and 0.82 ?? 0.02 mm year-1 in Regions 1 and 2, respectively. The ICE-5G(VM2) predictions capture the general temporal trend of the observations, although there is an apparent misfit for index points older than 2000 cal a BP. It is presently unknown whether these misfits are caused by possible tectonic uplift associated with the mid-Carolina Platform High or a flaw in the GIA model. A comparison of local tide gauge data with the Late Holocene RSL

  2. Development 3D model of adaptation of the Azerbaijan coastal zone at the various levels of Caspian Sea

    Science.gov (United States)

    Mammadov, Ramiz

    2013-04-01

    The most characteristic feature of the Caspian Sea which difference it on relation other seas is its periodical fluctuating in its level. In many coastal regions of the world the problem of influence of change of a sea level on activities of the human is a problem of the long-term future, but in region of Caspian Sea, especially in its Azerbaijan sector, it is already actual. Also experience accumulated here, can be use at the decision of problems of optimization of wildlife management in conditions of significant change of a sea level as model of potential consequences of warming of a climate. Changeableness of the level of the Caspian sea over many years can be observed better on the basis of natural observations, a systematic basis of which has been put by the academician E. Lents in 1830 year in Baku coastal line. According these data in 1882 the average level has reached its level -25.2 m. the highest point over the observations, i.e. by 1.8 m. higher than today's level. The average level over 1830-1930 was about -25.83 m. In 1960 some stabilization in the level, about 28,4 meters, in 1970 was a sharp drop, in 1977 - sharp drop reached -29.00 rn. The drop over the whole period of observations totaled 3.8 m within diapason -25.2 -29.0 m. In 1978 the level of the sea began to increase and in 1995 its average yearly mark reach -26,62 rn. Intensiveness of the rise of the level ever that period totaled in average about 14 cm per year. As a result of this rise of a sea level about 800 km2 of a coastal zone it has been flooded, the ecological situation has worsened, and there were ecological refugees. The damage to a coastal zone of Azerbaijan was 2 billion USA dollars. Caspian sea also has within-year (seasonal) variability equal 32 sm and sleeve and pileup change of level. Its estimate in Azerbaijan coastal zone is 0.8-1.0 m. In the coastal zone also necessary take into height of the wave which in these coasts can be 3.0 m height. All these means that in the

  3. Sediment and vegetation spatial dynamics facing sea-level rise in microtidal salt marshes: Insights from an ecogeomorphic model

    Science.gov (United States)

    Belliard, J.-P.; Di Marco, N.; Carniello, L.; Toffolon, M.

    2016-07-01

    Modeling efforts have considerably improved our understanding on the chief processes that govern the evolution of salt marshes under climate change. Yet the spatial dynamic response of salt marshes to sea-level rise that results from the interactions between the tidal landforms of interest and the presence of bio-geomorphic features has not been addressed explicitly. Accordingly, we use a modeling framework that integrates the co-evolution of the marsh platform and the embedded tidal networks to study sea-level rise effects on spatial sediment and vegetation dynamics in microtidal salt marshes considering different ecological scenarios. The analysis unveils mechanisms that drive spatial variations in sedimentation rates in ways that increase marsh resilience to rising sea-levels. In particular, marsh survival is related to the effectiveness of transport of sediments toward the interior marshland. This study hints at additional dynamics related to the modulation of channel cross-sections affecting sediment advection in the channels and subsequent delivery in the inner marsh, which should be definitely considered in the study of marsh adaptability to sea-level rise and posterior management.

  4. Sea-Level Rise and Land Subsidence in Deltas: Estimating Future Flood Risk Through Integrated Natural and Human System Modeling

    Science.gov (United States)

    Tessler, Z. D.; Vorosmarty, C. J.

    2016-12-01

    Deltas are highly sensitive to local human activities, land subsidence, regional water management, global sea-level rise, and climate extremes. We present a new delta flood exposure and risk framework for estimating the sensitivity of deltas to relative sea-level rise. We have applied this framework to a set of global environmental, geophysical, and social indicators over 48 major river deltas to quantify how contemporary risks vary across delta systems. The risk modeling framework incorporates upstream sediment flux and coastal land subsidence models, global empirical estimates of contemporary storm surge exposure, and population distribution and growth. Future scenarios are used to test the impacts on coastal flood risk of upstream dam construction, coastal population growth, accelerated sea-level rise, and enhanced storm surge. Results suggest a wide range of outcomes across different delta systems within each scenario. Deltas in highly engineered watersheds (Mississippi, Rhine) exhibit less sensitivity to increased dams due to saturation of sediment retention effects, though planned or under-construction dams are expected to have a substantial impact in the Yangtze, Irrawaddy, and Magdalena deltas. Population growth and sea-level rise are expected to be the dominant drivers of increased human risk in most deltas, with important exceptions in several countries, particularly China, where population are forecast to contract over the next several decades.

  5. Assimilating the along-track sea level anomaly into the regional ocean modeling system using the ensemble optimal interpolation

    Institute of Scientific and Technical Information of China (English)

    LYU Guokun; WANG Hui; ZHU Jiang; WANG Dakui; XIE Jiping; LIU Guimei

    2014-01-01

    The ensemble optimal interpolation (EnOI) is applied to the regional ocean modeling system (ROMS) with the ability to assimilate the along-track sea level anomaly (TSLA). This system is tested with an eddy-resolv-ing system of the South China Sea (SCS). Background errors are derived from a running seasonal ensemble to account for the seasonal variability within the SCS. A fifth-order localization function with a 250 km lo-calization radius is chosen to reduce the negative effects of sampling errors. The data assimilation system is tested from January 2004 to December 2006. The results show that the root mean square deviation (RMSD) of the sea level anomaly decreased from 10.57 to 6.70 cm, which represents a 36.6%reduction of error. The data assimilation reduces error for temperature within the upper 800 m and for salinity within the upper 200 m, although error degrades slightly at deeper depths. Surface currents are in better agreement with tra-jectories of surface drifters after data assimilation. The variance of sea level improves significantly in terms of both the amplitude and position of the strong and weak variance regions after assimilating TSLA. Results with AGE error (AGE) perform better than no AGE error (NoAGE) when considering the improvements of the temperature and the salinity. Furthermore, reasons for the extremely strong variability in the northern SCS in high resolution models are investigated. The results demonstrate that the strong variability of sea level in the high resolution model is caused by an extremely strong Kuroshio intrusion. Therefore, it is demonstrated that it is necessary to assimilate the TSLA in order to better simulate the SCS with high resolution models.

  6. Investigation of potential sea level rise impact on the Nile Delta, Egypt using digital elevation models.

    Science.gov (United States)

    Hasan, Emad; Khan, Sadiq Ibrahim; Hong, Yang

    2015-10-01

    In this study, the future impact of Sea Level Rise (SLR) on the Nile Delta region in Egypt is assessed by evaluating the elevations of two freely available Digital Elevation Models (DEMs): the SRTM and the ASTER-GDEM-V2. The SLR is a significant worldwide dilemma that has been triggered by recent climatic changes. In Egypt, the Nile Delta is projected to face SLR of 1 m by the end of the 21th century. In order to provide a more accurate assessment of the future SLR impact on Nile Delta's land and population, this study corrected the DEM's elevations by using linear regression model with ground elevations from GPS survey. The information for the land cover types and future population numbers were derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) land cover and the Gridded Population of the Worlds (GPWv3) datasets respectively. The DEM's vertical accuracies were assessed using GPS measurements and the uncertainty analysis revealed that the SRTM-DEM has positive bias of 2.5 m, while the ASTER-GDEM-V2 showed a positive bias of 0.8 m. The future inundated land cover areas and the affected population were illustrated based on two SLR scenarios of 0.5 m and 1 m. The SRTM DEM data indicated that 1 m SLR will affect about 3900 km(2) of cropland, 1280 km(2) of vegetation, 205 km(2) of wetland, 146 km(2) of urban areas and cause more than 6 million people to lose their houses. The overall vulnerability assessment using ASTER-GDEM-V2 indicated that the influence of SLR will be intense and confined along the coastal areas. For instance, the data indicated that 1 m SLR will inundate about 580 Km(2) (6%) of the total land cover areas and approximately 887 thousand people will be relocated. Accordingly, the uncertainty analysis of the DEM's elevations revealed that the ASTER-GDEM-V2 dataset product was considered the best to determine the future impact of SLR on the Nile Delta region.

  7. A numerical model to evaluate potential impacts of sea-level rise on groundwater resources in the Delaware coastal plain

    Science.gov (United States)

    He, C.; McKenna, T. E.; Wang, L.

    2013-12-01

    Sea level rise on the U.S. East Coast has accelerated much faster than in other parts of the world. In Delaware, the estimated sea level could rise as high as 1.5 meters by the year 2100 based on the information in IPCC (2007) and CCSP (2009). In this study, we used a 3-D variable-density groundwater flow model to study the movement of the fresh-water/salt-water interface and water table changes due to sea-level rise. Rather than developing a site-specific model, we analyzed the geospatial features of a serious of sub-watersheds along the coastline of the Delaware Estuary in Delaware using ArcGIS and constructed a representative model to capture the generalized flow patterns and saltwater intrusion rates that occur in typical area. Different scenarios with varying parameters were simulated. The simulation results were then applied to the Delaware River region to evaluate potential impacts of groundwater level changes on the potential land lose.

  8. Large-Ensemble modeling of past and future variations of the Antarctic Ice Sheet with a coupled ice-Earth-sea level model

    Science.gov (United States)

    Pollard, David; DeConto, Robert; Gomez, Natalya

    2016-04-01

    To date, most modeling of the Antarctic Ice Sheet's response to future warming has been calibrated using recent and modern observations. As an alternate approach, we apply a hybrid 3-D ice sheet-shelf model to the last deglacial retreat of Antarctica, making use of geologic data of the last ~20,000 years to test the model against the large-scale variations during this period. The ice model is coupled to a global Earth-sea level model to improve modeling of the bedrock response and to capture ocean-ice gravitational interactions. Following several recent ice-sheet studies, we use Large Ensemble (LE) statistical methods, performing sets of 625 runs from 30,000 years to present with systematically varying model parameters. Objective scores for each run are calculated using modern data and past reconstructed grounding lines, relative sea level records, cosmogenic elevation-age data and uplift rates. The LE results are analyzed to calibrate 4 particularly uncertain model parameters that concern marginal ice processes and interaction with the ocean. LE's are extended into the future with climates following RCP scenarios. An additional scoring criterion tests the model's ability to reproduce estimated sea-level high stands in the warm mid-Pliocene, for which drastic retreat mechanisms of hydrofracturing and ice-cliff failure are needed in the model. The LE analysis provides future sea-level-rise envelopes with well-defined parametric uncertainty bounds. Sensitivities of future LE results to Pliocene sea-level estimates, coupling to the Earth-sea level model, and vertical profiles of Earth properties, will be presented.

  9. Sea Level Variability During The 1993-1999 Obtained From A Assimilation of Topex/poseidon Altimetry Into A Global Ocean General Circulation Model

    Science.gov (United States)

    Staneva, J.; Wenzel, M.; Schroeter, J.

    Sea surface height variability is studied from ocean model simulations and altimer data. The estimate of the ocean state is obtained by constraining the LSG model of the Max Plank Institute of Meteorology, Hamburg. Seven years (1993-1999) TOPEX/POSEIDON (T/P) sea surface heights relative to the EGM96 geoid model are assimilated into the model. 4D-VAR is used to optimize a set of control variables. The impact of the geoid data is presented by comparing the results from assimilating of mean plus time variability of sea surface heigh, or assimilating of sea level tempo- ral anomaly provided by T/P only. The sea surface height variability is analyzed. The individual effects of thermal and haline variability on the sea level are investigated as well.

  10. Resolving discrepancies between hydraulic and chemical calibration data for seawater intrusion groundwater flow models by considering climate-driven sea level change.

    Energy Technology Data Exchange (ETDEWEB)

    J. Chapman; A. Hassan; K. Pohlmann

    2001-10-18

    Groundwater models of seawater intrusion environments can be calibrated using both hydraulic and chemical information. The possible impact of the long-term transient process of sea level change is difficult to identify, but important to accurate simulation of present conditions. The response times of the pressure and chemical fields to major fluctuations in sea level change are investigated

  11. BRICK v0.2, a simple, accessible, and transparent model framework for climate and regional sea-level projections

    Science.gov (United States)

    Wong, Tony E.; Bakker, Alexander M. R.; Ruckert, Kelsey; Applegate, Patrick; Slangen, Aimée B. A.; Keller, Klaus

    2017-07-01

    Simple models can play pivotal roles in the quantification and framing of uncertainties surrounding climate change and sea-level rise. They are computationally efficient, transparent, and easy to reproduce. These qualities also make simple models useful for the characterization of risk. Simple model codes are increasingly distributed as open source, as well as actively shared and guided. Alas, computer codes used in the geosciences can often be hard to access, run, modify (e.g., with regards to assumptions and model components), and review. Here, we describe the simple model framework BRICK (Building blocks for Relevant Ice and Climate Knowledge) v0.2 and its underlying design principles. The paper adds detail to an earlier published model setup and discusses the inclusion of a land water storage component. The framework largely builds on existing models and allows for projections of global mean temperature as well as regional sea levels and coastal flood risk. BRICK is written in R and Fortran. BRICK gives special attention to the model values of transparency, accessibility, and flexibility in order to mitigate the above-mentioned issues while maintaining a high degree of computational efficiency. We demonstrate the flexibility of this framework through simple model intercomparison experiments. Furthermore, we demonstrate that BRICK is suitable for risk assessment applications by using a didactic example in local flood risk management.

  12. Assessing the Effects of Sea Level Rise on Plum Island Estuary Marshes Using a Hydrodynamic-marsh Modeling Tool

    Science.gov (United States)

    Demissie, H. K.; Bilskie, M. V.; Hagen, S. C.; Morris, J. T.; Alizad, K.

    2015-12-01

    Sea level rise (SLR) can significantly impact both human and ecological habitats in coastal and inland regions. Studies show that coastal estuaries and marsh systems are at the risk of losing their productivity under increasing rates of SLR (Donnelly and Bertness, 2001; Warren and Niering, 1993). The integrated hydrodynamic-marsh model (Hagen et al., 2013 & Alizad et al., 2015) uses a set of parameters and conditions to simulate tidal flow through the salt marsh of Plum Island Estuary, Massachusetts. The hydrodynamic model computes mean high water (MHW) and mean low water (MLW) and is coupled to the zero-dimensional Marsh Equilibrium Model (Morris et al. 2002) to estimate changes in biomass productivity and accretion. The coupled hydrodynamic-marsh model was used to examine the effects of different scenarios of SLR (Parris et al., 2012) on salt marsh productivity for the year 2100 in the Plum Island Estuary. In this particular study, responses of salt marsh production for different scenarios of SLR were compared. The study shows higher productivity of salt marsh under a low SLR scenario and lower productivity under the higher SLR. The study also demonstrates the migration of salt marshes under higher SLR scenarios. References: Alizad, K., S. C. Hagen, Morris, J.T., Bacopoulos, P., Bilskie, M.V., and John, F.W. 2015. A coupled, two-dimensional hydrodynamic-marsh model with biological feedback. Limnology and Oceanography, In review. Donnelly, J.P., and M.D. Bertness. 2001. Rapid shoreward encroachment of salt marsh cordgrass in response to accelerated sea-level rise. Proceedings of the National Academy of Sciences 98: 14218-14223.Hagen, S.C., J.T. Morris, P. Bacopoulos, and J. Weishampel. 2013. Sea-Level Rise Impact on a Salt Marsh System of the Lower St. Johns River. ASCE Journal of Waterway, Port, Coastal, and Ocean Engineering, Vol. 139, No. 2, March/April 2013, pp. 118-125.Morris, J.T., P.V. Sundareshwar, C.T. Nietch, B. Kjerfve, and D.R. Cahoon. 2002. Responses

  13. Soil Accretionary Dynamics, Sea-Level Rise and the Survival of Wetlands in Venice Lagoon: A Field and Modelling Approach

    Science.gov (United States)

    Day, J. W.; Rybczyk, J.; Scarton, F.; Rismondo, A.; Are, D.; Cecconi, G.

    1999-11-01

    Over the past century, Venice Lagoon (Italy) has experienced a high rate of wetland loss. To gain an understanding of the factors leading to this loss, from March 1993 until May 1996 the soil accretionary dynamics of these wetlands were studied. Vertical accretion, short term sedimentation, soil vertical elevation change and horizontal shoreline change were measured at several sites with varying sediment availability and wave energy. Short term sedimentation averaged 3-7 g dry m -2day -1per site with a maximum of 76 g m -2 day -1. The highest values were measured during strong pulsing events, such as storms and river floods, that mobilized and transported suspended sediments. Accretion ranged from 2-23 mm yr -1and soil elevation change ranged from -32 to 13·8 mm yr -1. The sites with highest accretion were near a river mouth and in an area where strong wave energy resuspended bottom sediments that were deposited on the marsh surface. A marsh created with dredged spoil had a high rate of elevation loss, probably due mainly to compaction. Shoreline retreat and expansion of tidal channels also occurred at several sites due to high wave energy and a greater tidal prism. The current rate of elevation gain at some sites was not sufficient to offset relative sea-level rise. The results suggest that reduction of wave energy and increasing sediment availability are needed to offset wetland loss in different areas of the lagoon. Using the data collected as part of this project, we developed a wetland elevation model designed to predict the effect of increasing rates of eustatic sea-level rise on wetland sustainability. The advantage of this model, in conjunction with measured short-term rates of soil elevation change, to determine sustainability is that the model integrates the effects of long term processes (e.g. compaction and decomposition) and takes into account feedback mechanisms that affect elevation. Specifically, changes in elevation can result in changes in

  14. (abstract) Using TOPEX/Poseidon Sea Level Observations to Test the Sensitivity of an Ocean Model to Wind Forcing

    Science.gov (United States)

    Fu, Lee-Lueng; Chao, Yi

    1996-01-01

    It has been demonstrated that current-generation global ocean general circulation models (OGCM) are able to simulate large-scale sea level variations fairly well. In this study, a GFDL/MOM-based OGCM was used to investigate its sensitivity to different wind forcing. Simulations of global sea level using wind forcing from the ERS-1 Scatterometer and the NMC operational analysis were compared to the observations made by the TOPEX/Poseidon (T/P) radar altimeter for a two-year period. The result of the study has demonstrated the sensitivity of the OGCM to the quality of wind forcing, as well as the synergistic use of two spaceborne sensors in advancing the study of wind-driven ocean dynamics.

  15. An eclectic morphostratigraphic model for the sedimentary response to Holocene sea-level rise in northwest Europe

    Science.gov (United States)

    Allen, J. R. L.

    2003-09-01

    The improved empirical understanding of silt facies in Holocene coastal sequences provided by such as diatom, foraminifera, ostracode and testate amoebae analysis, combined with insights from quantitative stratigraphic and hydraulic simulations, has led to an inclusive, integrated model for the palaeogeomorphology, stratigraphy, lithofacies and biofacies of northwest European Holocene coastal lowlands in relation to sea-level behaviour. The model covers two general circumstances and is empirically supported by a range of field studies in the Holocene deposits of a number of British estuaries, particularly, the Severn. Where deposition was continuous over periods of centuries to millennia, and sea level fluctuated about a rising trend, the succession consists of repeated cycles of silt and peat lithofacies and biofacies in which series of transgressive overlaps (submergence sequences) alternate with series of regressive overlaps (emergence sequences) in association with the waxing and waning of tidal creek networks. Environmental and sea-level change are closely coupled, and equilibrium and secular pattern is of the kind represented ideally by a closed limit cycle. In the second circumstance, characteristic of unstable wetland shores and generally affecting smaller areas, coastal erosion ensures that episodes of deposition in the high intertidal zone last no more than a few centuries. The typical response is a series of regressive overlaps (emergence sequence) in erosively based high mudflat and salt-marsh silts that record, commonly as annual banding, exceptionally high deposition rates and a state of strong disequilibrium. Environmental change, including creek development, and sea-level movement are uncoupled. Only if deposition proceeds for a sufficiently long period, so that marshes mature, are equilibrium and close coupling regained.

  16. USACE Extreme Sea levels

    Science.gov (United States)

    2014-03-14

    report summarising the results of the research, together with a set of recommendations arising from the research. This report describes progress to...Southampton University at HR Wallingford and subsequent teleconference with Heidi Moritz and Kate White. The notes summarising the findings of the...suggestion was made that we may want to begin talking about extreme water levels separate from storms. Ivan mentioned an analysis of storminess which

  17. Using modelling to predict impacts of sea level rise and increased turbidity on seagrass distributions in estuarine embayments

    Science.gov (United States)

    Davis, Tom R.; Harasti, David; Smith, Stephen D. A.; Kelaher, Brendan P.

    2016-11-01

    Climate change induced sea level rise will affect shallow estuarine habitats, which are already under threat from multiple anthropogenic stressors. Here, we present the results of modelling to predict potential impacts of climate change associated processes on seagrass distributions. We use a novel application of relative environmental suitability (RES) modelling to examine relationships between variables of physiological importance to seagrasses (light availability, wave exposure, and current flow) and seagrass distributions within 5 estuarine embayments. Models were constructed separately for Posidonia australis and Zostera muelleri subsp. capricorni using seagrass data from Port Stephens estuary, New South Wales, Australia. Subsequent testing of models used independent datasets from four other estuarine embayments (Wallis Lake, Lake Illawarra, Merimbula Lake, and Pambula Lake) distributed along 570 km of the east Australian coast. Relative environmental suitability models provided adequate predictions for seagrass distributions within Port Stephens and the other estuarine embayments, indicating that they may have broad regional application. Under the predictions of RES models, both sea level rise and increased turbidity are predicted to cause substantial seagrass losses in deeper estuarine areas, resulting in a net shoreward movement of seagrass beds. Seagrass species distribution models developed in this study provide a valuable tool to predict future shifts in estuarine seagrass distributions, allowing identification of areas for protection, monitoring and rehabilitation.

  18. The conservation value of elevation data accuracy and model sophistication in reserve design under sea-level rise.

    Science.gov (United States)

    Zhu, Mingjian; Hoctor, Tom; Volk, Mike; Frank, Kathryn; Linhoss, Anna

    2015-10-01

    Many studies have explored the value of using more sophisticated coastal impact models and higher resolution elevation data in sea-level rise (SLR) adaptation planning. However, we know little about to what extent the improved models and data could actually lead to better conservation outcomes under SLR. This is important to know because high-resolution data are likely to not be available in some data-poor coastal areas in the world and running more complicated coastal impact models is relatively time-consuming, expensive, and requires assistance by qualified experts and technicians. We address this research question in the context of identifying conservation priorities in response to SLR. Specifically, we investigated the conservation value of using more accurate light detection and ranging (Lidar)-based digital elevation data and process-based coastal land-cover change models (Sea Level Affecting Marshes Model, SLAMM) to identify conservation priorities versus simple "bathtub" models based on the relatively coarse National Elevation Dataset (NED) in a coastal region of northeast Florida. We compared conservation outcomes identified by reserve design software (Zonation) using three different model dataset combinations (Bathtub-NED, Bathtub-Lidar, and SLAMM-Lidar). The comparisons show that the conservation priorities are significantly different with different combinations of coastal impact models and elevation dataset inputs. The research suggests that it is valuable to invest in more accurate coastal impact models and elevation datasets in SLR adaptive conservation planning because this model-dataset combination could improve conservation outcomes under SLR. Less accurate coastal impact models, including ones created using coarser Digital Elevation Model (DEM) data can still be useful when better data and models are not available or feasible, but results need to be appropriately assessed and communicated. A future research priority is to investigate how

  19. Application of model studies for quality control of bottom pressure based GLOSS sea level gauge at Takoradi Harbour (Ghana, West Africa)

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Mehra, P.; Desai, R.G.P.; Dotse, J.; Odammetey, J.T.; Nkebi, E.K.; VijayKumar, K.; Prabhudesai, S.

    Quality-control of bottom pressure based sea level gauge has been effected using a statistically derived simple linear model constructed from a set of bottom pressures and concurrent tide-staff measurements. The study reveals that the crucial factor...

  20. Modeling complex flow dynamics of fluvial floods exacerbated by sea level rise in the Ganges-Brahmaputra-Meghna Delta

    Science.gov (United States)

    Ikeuchi, Hiroaki; Hirabayashi, Yukiko; Yamazaki, Dai; Kiguchi, Masashi; Koirala, Sujan; Nagano, Takanori; Kotera, Akihiko; Kanae, Shinjiro

    2015-12-01

    Global warming is likely to exacerbate future fluvial floods in the world’s mega-delta regions due to both changing climate and rising sea levels. However, the effects of sea level rise (SLR) on fluvial floods in such regions have not been taken into account in current global assessments of future flood risk, due to the difficulties in modeling channel bifurcation and the backwater effect. We used a state-of-the-art global river routing model to demonstrate how these complexities contribute to future flood hazard associated with changing climate and SLR in the world’s largest mega-delta region, the Ganges-Brahmaputra-Meghna Delta. The model demonstrated that flood water in the main channels flows into tributaries through bifurcation channels, which resulted in an increase in inundation depth in deltaic regions. We found that there were large areas that experienced an increase in inundation depth and period not directly from the SLR itself but from the backwater effect of SLR, and the effect propagated upstream to locations far from the river mouth. Projections under future climate scenarios as well as SLR indicated that exposure to fluvial floods will increase in the last part of the 21st century, and both SLR and channel bifurcation make meaningful contributions.

  1. MODEL SPASIAL DINAMIK GENANGAN AKIBAT KENAIKAN MUKA AIR LAUT DI PESISIR SEMARANG (Spatial Dynamic Model of Inundated area due to Sea Level rise at Semarang coastal Area

    Directory of Open Access Journals (Sweden)

    Ifan R Suhelmi

    2014-05-01

    Full Text Available ABSTRAK Kota Semarang merupakan kota pesisir di Provinsi Jawa Tengah yang memiliki topografi datar pada wilayah laut yang biasa disebut dengan kota bawah dan bergunung pada bagian atasnya yang biasa disebut dengan kota atas. Kota bawah memiliki kerentanan yang tinggi terhadap genangan akibat kenaikan muka air laut, hal ini disebabkan olehkondisi topografi yang datar. Penelitian ini dilakukan untuk memberikan gambaran secara dinamik distribusi genangan akibat berbagai skenario kenaikan muka air laut. Model spasial dinamik menggunakan Flash yang berfungsi memberikan gambaran secara interaktif dan real time pada berbagai skenario kenaikan muka air laut. Skenario kenaikan muka air laut menggunakan skenario IPCC hingga tahun 2100. Hasil studi menunjukkan bahwa terjadi kenaikan jumlah genangan dari 599,4 ha pada tahun 2020 menjadi 4.235,4 ha pada tahun 2100.   ABSTRACT Semarang is one of coastal city located at Central Java Province. It has flatten topography at coastal area called “downside town” and hilly topography at upper area called “topside town”.  Ownside town was highly vulnerable to sea level rise caused by it’s topographic condition and the land subsidence phenomena. This research conducted to mapeed the inundated area due to sea level rise at many scenarios of sea level rise. The dynamic spatialmodel of sea level rise represented using flash techmology to showed distributed area inundated by sea level rise. The scenario of sea level rise by IPCC prediction was used at this study. The stuty showed that the inundated area increased from 599.4 ha at year 2020 to 4,235.4 ha at 2100.

  2. Interactions between barrier islands and backbarrier marshes affect island system response to sea level rise: Insights from a coupled model

    Science.gov (United States)

    Walters, David; Moore, Laura J.; Duran Vinent, Orencio; Fagherazzi, Sergio; Mariotti, Giulio

    2014-09-01

    Interactions between backbarrier marshes and barrier islands will likely play an important role in determining how low-lying coastal systems respond to sea level rise and changes in storminess in the future. To assess the role of couplings between marshes and barrier islands under changing conditions, we develop and apply a coupled barrier island-marsh model (GEOMBEST+) to assess the impact of overwash deposition on backbarrier marsh morphology and of marsh morphology on rates of island migration. Our model results suggest that backbarrier marsh width is in a constant state of change until either the backbarrier basin becomes completely filled or backbarrier marsh deposits have completely eroded away. Results also suggest that overwash deposition is an important source of sediment, which allows existing narrow marshes to be maintained in a long-lasting alternate state (~500 m wide in the Virginia Barrier Islands) within a range of conditions under which they would otherwise disappear. The existence of a narrow marsh state is supported by observations of backbarrier marshes along the eastern shore of Virginia. Additional results suggest that marshes reduce accommodation in the backbarrier bay, which, in turn, decreases island migration rate. As climate change results in sea level rise, and the increased potential for intense hurricanes resulting in overwash, it is likely that these couplings will become increasingly important in determining future system behavior.

  3. 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...

  4. Assimilation of TOPEX Sea Level Measurements with a Reduced-Gravity, Shallow Water Model of the Tropical Pacific Ocean

    Science.gov (United States)

    Fukumori, Ichiro

    1995-01-01

    Sea surface height variability measured by TOPEX is analyzed in the tropical Pacific Ocean by way of assimilation into a wind-driven, reduced-gravity, shallow water model using an approximate Kalman filter and smoother. The analysis results in an optimal fit of the dynamic model to the observations, providing it dynamically consistent interpolation of sea level and estimation of the circulation. Nearly 80% of the expected signal variance is accounted for by the model within 20 deg of the equator, and estimation uncertainty is substantially reduced by the voluminous observation. Notable features resolved by the analysis include seasonal changes associated with the North Equatorial Countercurrent and equatorial Kelvin and Rossby waves. Significant discrepancies are also found between the estimate and TOPEX measurements, especially near the eastern boundary. Improvements in the estimate made by the assimilation are validated by comparisons with independent tide gauge and current meter observations. The employed filter and smoother are based on approximately computed estimation error covariance matrices, utilizing a spatial transformation and an symptotic approximation. The analysis demonstrates the practical utility of a quasi-optimal filter and smoother.

  5. Analogue modelling of the influence of ice shelf collapse on the flow of ice sheets grounded below sea-level

    Science.gov (United States)

    Corti, Giacomo; Zeoli, Antonio

    2016-04-01

    The sudden breakup of ice shelves is expected to result in significant acceleration of inland glaciers, a process related to the removal of the buttressing effect exerted by the ice shelf on the tributary glaciers. This effect has been tested in previous analogue models, which however applied to ice sheets grounded above sea level (e.g., East Antarctic Ice Sheet; Antarctic Peninsula and the Larsen Ice Shelf). In this work we expand these previous results by performing small-scale laboratory models that analyse the influence of ice shelf collapse on the flow of ice streams draining an ice sheet grounded below sea level (e.g., the West Antarctic Ice Sheet). The analogue models, with dimensions (width, length, thickness) of 120x70x1.5cm were performed at the Tectonic Modelling Laboratory of CNR-IGG of Florence, Italy, by using Polydimethilsyloxane (PDMS) as analogue for the flowing ice. This transparent, Newtonian silicone has been shown to well approximate the rheology of natural ice. The silicone was allowed to flow into a water reservoir simulating natural conditions in which ice streams flow into the sea, terminating in extensive ice shelves which act as a buttress for their glaciers and slow their flow. The geometric scaling ratio was 10(-5), such that 1cm in the models simulated 1km in nature; velocity of PDMS (a few mm per hour) simulated natural velocities of 100-1000 m/year. Instability of glacier flow was induced by manually removing a basal silicone platform (floating on water) exerting backstresses to the flowing analogue glacier: the simple set-up adopted in the experiments isolates the effect of the removal of the buttressing effect that the floating platform exerts on the flowing glaciers, thus offering insights into the influence of this parameter on the flow perturbations resulting from a collapse event. The experimental results showed a significant increase in glacier velocity close to its outlet following ice shelf breakup, a process similar to what

  6. 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

  7. An assessment of uncertainties in using volume-area modelling for computing the twenty-first century glacier contribution to sea-level change

    Directory of Open Access Journals (Sweden)

    A. B. A. Slangen

    2011-08-01

    Full Text Available A large part of present-day sea-level change is formed by the melt of glaciers and ice caps (GIC. This study focuses on the uncertainties in the calculation of the GIC contribution on a century timescale. The model used is based on volume-area scaling, combined with the mass balance sensitivity of the GIC. We assess different aspects that contribute to the uncertainty in the prediction of the contribution of GIC to future sea-level rise, such as (1 the volume-area scaling method (scaling factor, (2 the glacier data, (3 the climate models, and (4 the emission scenario. Additionally, a comparison of the model results to the 20th century GIC contribution is presented.

    We find that small variations in the scaling factor cause significant variations in the initial volume of the glaciers, but only limited variations in the glacier volume change. If two existing glacier inventories are tuned such that the initial volume is the same, the GIC sea-level contribution over 100 yr differs by 0.027 m or 18 %. It appears that the mass balance sensitivity is also important: variations of 20 % in the mass balance sensitivity have an impact of 17 % on the resulting sea-level projections. Another important factor is the choice of the climate model, as the GIC contribution to sea-level change largely depends on the temperature and precipitation taken from climate models. Connected to this is the choice of emission scenario, used to drive the climate models. Combining all the uncertainties examined in this study leads to a total uncertainty of 0.052 m or 35 % in the GIC contribution to global mean sea level. Reducing the variance in the climate models and improving the glacier inventories will significantly reduce the uncertainty in calculating the GIC contributions, and are therefore crucial actions to improve future sea-level projections.

  8. Seasonal Change of Steric Sea Level in the GIN Seas

    Institute of Scientific and Technical Information of China (English)

    LI Lei; WANG Huijuan; SUN Ruili

    2011-01-01

    The Greenland Sea, Iceland Sea, and Norwegian Sea (GIN seas) form the main channel connecting the Arctic Ocean with other Oceans, where significant water and energy exchange take place, and play an important role in global climate change. In this study steric sea level, associated with temperature and salinity, in the GIN seas is examined based on analysis of the monthly temperature and salinity fields from Polar science center Hydrographic Climatology (PHC3.0). A method proposed by Tabata et al. is used to calculate steric sea level, in which, steric sea level change due to thermal expansion and haline contraction is termed as the thermosteric component (TC) and the halosteric component (SC), recpectively. Total steric sea level (TSSL) change is the sum of TC and SC. The study shows that SC is making more contributions than TC to the seasonal change of TSSL in the Greenland Sea, whereas TC contributes more in the Norwegian and the Iceland Seas. Annual variation of TSSL is larger than 50ram over most regions of the GIN Seas, and can be larger than 200mm at some locations such as 308mm at 76.5°N, 12.5°E and 246mm at 77.50N, 17.5°W.

  9. Impacts of Climate Change on Estuarine Habitats in the UK: Critical Evaluation of the Saltmarshes and Sea-Level Rise Model (SLAMM)

    Science.gov (United States)

    Pylarinou, A.; French, J.; Burningham, H.

    2013-12-01

    Estuarine wetland environments are at risk of significant transformation and loss due to sea-level rise and there is an increasing need to model such impacts. In a UK context, the relatively small size and morphological complexity of many estuaries necessitates a high spatial resolution but models must also be capable of efficient application over time scales of decades to centuries that correspond to widely used IPCC climate change scenarios. Little previous work of this kind has been carried out to date in the UK. An exception is the EU-funded BRANCH project, which simulated the drowning of intertidal topography, due to sea-level rise, and potential mudflat and saltmarsh responses to a change in inundation regime. However, this approach neglects the interplay of sea-level rise and sedimentation. Accordingly, this study investigates the potential of a more dynamic spatial landscape model to represent meso-scale impacts of sea-level rise on UK estuary environments. It takes as a starting point the Sea Level Affecting Marshes Model (SLAMM), which has been widely used in the USA. This is built around the US National Wetlands Inventory classification and adapting it to suit the tidal sedimentary environments and habitats typical of the UK requires changes to the source code. This paper presents results obtained from the application of an appropriately modified SLAMM code to contrasting estuarine environments in eastern England. The aim is to evaluate the ability of SLAMM to produce plausible projections of intertidal habitat change. The estuaries studied are covered by high-resolution altimetry data, and an extensive literature on their physical process regime allows the parameterisation of the various sub-models in SLAMM. A Matlab-based shell is used to perform an initial sensitivity analysis to better understand the nature of the modelled sea-level rise effects. This shell also provides a framework for Monte Carlo simulations forced by a set of UKCP09 sea-level rise

  10. A modeling study of the role that bottom topography plays in Gulf Stream dynamics and in influencing the tilt of mean sea level along the US East Coast

    Science.gov (United States)

    Ezer, Tal

    2017-05-01

    Two aspects of the interactions between the Gulf Stream (GS) and the bottom topography are investigated: 1. the spatial variations associated with the north-south tilt of mean sea level along the US East Coast and 2. the high-frequency temporal variations of coastal sea level (CSL) that are related to Gulf Stream dynamics. A regional ocean circulation model is used to assess the role of topography; this is done by conducting numerical simulations of the GS with two different topographies-one case with a realistic topography and another case with an idealized smooth topography that neglects the details of the coastline and the very deep ocean. High-frequency oscillations (with a 5-day period) in the zonal wind and in the GS transport are imposed on the model; the source of the GS variability is either the Florida Current (FC) in the south or the Slope Current (SC) in the north. The results demonstrate that the abrupt change of topography at Cape Hatteras, near the point where the GS separates from the coast, amplifies the northward downward mean sea level tilt along the coast there. The results suggest that idealized or coarse resolution models that do not resolve the details of the coastline may underestimate the difference between the higher mean sea level in the South Atlantic Bight (SAB) and the lower mean sea level in the Mid-Atlantic Bight (MAB). Imposed variations in the model's GS transport can generate coherent sea level variability along the coast, similar to the observations. However, when the bottom topography in the model is modified (or not well resolved), the shape of the coastline and the continental shelf influence the propagation of coastal-trapped waves and impact the CSL variability. The results can explain the different characteristics of sea level variability in the SAB and in the MAB and help understand unexpected water level anomalies and flooding related to remote influence of the GS.

  11. Development of a model to simulate groundwater inundation induced by sea-level rise and high tides in Honolulu, Hawaii.

    Science.gov (United States)

    Habel, Shellie; Fletcher, Charles H; Rotzoll, Kolja; El-Kadi, Aly I

    2017-05-01

    Many of the world's largest cities face risk of sea-level rise (SLR) induced flooding owing to their limited elevations and proximities to the coastline. Within this century, global mean sea level is expected to reach magnitudes that will exceed the ground elevation of some built infrastructure. The concurrent rise of coastal groundwater will produce additional sources of inundation resulting from narrowing and loss of the vertical unsaturated subsurface space. This has implications for the dense network of buried and low-lying infrastructure that exists across urban coastal zones. Here, we describe a modeling approach that simulates narrowing of the unsaturated space and groundwater inundation (GWI) generated by SLR-induced lifting of coastal groundwater. The methodology combines terrain modeling, groundwater monitoring, estimation of tidal influence, and numerical groundwater-flow modeling to simulate future flood scenarios considering user-specified tide stages and magnitudes of SLR. We illustrate the value of the methodology by applying it to the heavily urbanized and low-lying Waikiki area of Honolulu, Hawaii. Results indicate that SLR of nearly 1 m generates GWI across 23% of the 13 km(2) study area, threatening $5 billion of taxable real estate and 48 km of roadway. Analysis of current conditions reveals that 86% of 259 active cesspool sites in the study area are likely inundated. This suggests that cesspool effluent is currently entering coastal groundwater, which not only leads to degradation of coastal environments, but also presents a future threat to public health as GWI would introduce effluent at the ground surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

    NARCIS (Netherlands)

    Fettweis, X.; Franco, B.; Tedesco, M.; van Angelen, J.H.; Lenaerts, J.T.M.; van den Broeke, M.R.; Gallée, H.

    2013-01-01

    To estimate the sea level rise (SLR) originating from changes in surface mass balance (SMB) of the Greenland ice sheet (GrIS), we present 21st century climate projections obtained with the regional climate model MAR (Mod`ele Atmosph´erique R´egional), forced by output of three CMIP5 (Coupled Model I

  13. Global Warming and Caspian Sea Level Fluctuations

    CERN Document Server

    Ardakanian, Reza

    2013-01-01

    Coastal regions have a high social, economical and environmental importance. Due to this importance the sea level fluctuations can have many bad consequences. In this research the correlation between the increasing trend of temperature in coastal stations due to Global Warming and the Caspian Sea level has been established. The Caspian Sea level data has been received from the Jason-1 satellite. It was resulted that the monthly correlation between the temperature and sea level is high and also positive and almost the same for all the stations. But the yearly correlation was negative. It means that the sea level has decreased by the increase in temperature.

  14. Ecological niche modeling of coastal dune plants and future potential distribution in response to climate change and sea level rise.

    Science.gov (United States)

    Mendoza-González, Gabriela; Martínez, M Luisa; Rojas-Soto, Octavio R; Vázquez, Gabriela; Gallego-Fernández, Juan B

    2013-08-01

    Climate change (CC) and sea level rise (SLR) are phenomena that could have severe impacts on the distribution of coastal dune vegetation. To explore this we modeled the climatic niches of six coastal dunes plant species that grow along the shoreline of the Gulf of Mexico and the Yucatan Peninsula, and projected climatic niches to future potential distributions based on two CC scenarios and SLR projections. Our analyses suggest that distribution of coastal plants will be severely limited, and more so in the case of local endemics (Chamaecrista chamaecristoides, Palafoxia lindenii, Cakile edentula). The possibilities of inland migration to the potential 'new shoreline' will be limited by human infrastructure and ecosystem alteration that will lead to a 'coastal squeeze' of the coastal habitats. Finally, we identified areas as future potential refuges for the six species in central Gulf of Mexico, and northern Yucatán Peninsula especially under CC and SLR scenarios.

  15. CO2 and sea level

    Science.gov (United States)

    Bell, Peter M.

    There is considerable discussion currently about the potential effects of carbon dioxide build-up in the atmosphere over the next several decades. The sources of information are two Government funded reports, one by the National Research Council (NRC), the other by the Environment Protection Agency (EPA), both were released within the last five months. The reports were described recently as being conservative, although the consequences of the resulting greenhouse effects are deemed inevitable. Atmospheric warming on a global scale of as much as 5°C cannot be avoided, only perhaps delayed by a few years at best (Environ. Sci. Technol, 18, 45A-46A, 1984). The cause is the burning of fossil fuels. Oil will not be too important because its supplies are predictably exhausted on the time scale of 50-100 years. Coal burning is considered as the main source of carbon dioxide. Among the more spectacular results of a global temperature rise over the next 100 years is the expected rise in sea level of a minimum of 70 cm (Oceanus, Winter, 1983/84). If the West Antarctic Ice Sheet breaks up and melts, the rise could be in the several meter range. Sea level rose only 15 cm in the past century.

  16. The El Salvador and Philippines Tsunamis of August 2012: Insights from Sea Level Data Analysis and Numerical Modeling

    Science.gov (United States)

    Heidarzadeh, Mohammad; Satake, Kenji

    2014-12-01

    We studied two tsunamis from 2012, one generated by the El Salvador earthquake of 27 August ( Mw 7.3) and the other generated by the Philippines earthquake of 31 August ( Mw 7.6), using sea level data analysis and numerical modeling. For the El Salvador tsunami, the largest wave height was observed in Baltra, Galapagos Islands (71.1 cm) located about 1,400 km away from the source. The tsunami governing periods were around 9 and 19 min. Numerical modeling indicated that most of the tsunami energy was directed towards the Galapagos Islands, explaining the relatively large wave height there. For the Philippines tsunami, the maximum wave height of 30.5 cm was observed at Kushimoto in Japan located about 2,700 km away from the source. The tsunami governing periods were around 8, 12 and 29 min. Numerical modeling showed that a significant part of the far-field tsunami energy was directed towards the southern coast of Japan. Fourier and wavelet analyses as well as numerical modeling suggested that the dominant period of the first wave at stations normal to the fault strike is related to the fault width, while the period of the first wave at stations in the direction of fault strike is representative of the fault length.

  17. Modeled Sea Level Rise Impacts on Coastal Ecosystems at Six Major Estuaries on Florida's Gulf Coast: Implications for Adaptation Planning.

    Science.gov (United States)

    Geselbracht, Laura L; Freeman, Kathleen; Birch, Anne P; Brenner, Jorge; Gordon, Doria R

    2015-01-01

    The Sea Level Affecting Marshes Model (SLAMM) was applied at six major estuaries along Florida's Gulf Coast (Pensacola Bay, St. Andrews/Choctawhatchee Bays, Apalachicola Bay, Southern Big Bend, Tampa Bay and Charlotte Harbor) to provide quantitative and spatial information on how coastal ecosystems may change with sea level rise (SLR) and to identify how this information can be used to inform adaption planning. High resolution LiDAR-derived elevation data was utilized under three SLR scenarios: 0.7 m, 1 m and 2 m through the year 2100 and uncertainty analyses were conducted on selected input parameters at three sites. Results indicate that the extent, spatial orientation and relative composition of coastal ecosystems at the study areas may substantially change with SLR. Under the 1 m SLR scenario, total predicted impacts for all study areas indicate that coastal forest (-69,308 ha; -18%), undeveloped dry land (-28,444 ha; -2%) and tidal flat (-25,556 ha; -47%) will likely face the greatest loss in cover by the year 2100. The largest potential gains in cover were predicted for saltmarsh (+32,922 ha; +88%), transitional saltmarsh (+23,645 ha; na) and mangrove forest (+12,583 ha; +40%). The Charlotte Harbor and Tampa Bay study areas were predicted to experience the greatest net loss in coastal wetlands The uncertainty analyses revealed low to moderate changes in results when some numerical SLAMM input parameters were varied highlighting the value of collecting long-term sedimentation, accretion and erosion data to improve SLAMM precision. The changes predicted by SLAMM will affect exposure of adjacent human communities to coastal hazards and ecosystem functions potentially resulting in impacts to property values, infrastructure investment and insurance rates. The results and process presented here can be used as a guide for communities vulnerable to SLR to identify and prioritize adaptation strategies that slow and/or accommodate the changes underway.

  18. Modeled Sea Level Rise Impacts on Coastal Ecosystems at Six Major Estuaries on Florida's Gulf Coast: Implications for Adaptation Planning.

    Directory of Open Access Journals (Sweden)

    Laura L Geselbracht

    Full Text Available The Sea Level Affecting Marshes Model (SLAMM was applied at six major estuaries along Florida's Gulf Coast (Pensacola Bay, St. Andrews/Choctawhatchee Bays, Apalachicola Bay, Southern Big Bend, Tampa Bay and Charlotte Harbor to provide quantitative and spatial information on how coastal ecosystems may change with sea level rise (SLR and to identify how this information can be used to inform adaption planning. High resolution LiDAR-derived elevation data was utilized under three SLR scenarios: 0.7 m, 1 m and 2 m through the year 2100 and uncertainty analyses were conducted on selected input parameters at three sites. Results indicate that the extent, spatial orientation and relative composition of coastal ecosystems at the study areas may substantially change with SLR. Under the 1 m SLR scenario, total predicted impacts for all study areas indicate that coastal forest (-69,308 ha; -18%, undeveloped dry land (-28,444 ha; -2% and tidal flat (-25,556 ha; -47% will likely face the greatest loss in cover by the year 2100. The largest potential gains in cover were predicted for saltmarsh (+32,922 ha; +88%, transitional saltmarsh (+23,645 ha; na and mangrove forest (+12,583 ha; +40%. The Charlotte Harbor and Tampa Bay study areas were predicted to experience the greatest net loss in coastal wetlands The uncertainty analyses revealed low to moderate changes in results when some numerical SLAMM input parameters were varied highlighting the value of collecting long-term sedimentation, accretion and erosion data to improve SLAMM precision. The changes predicted by SLAMM will affect exposure of adjacent human communities to coastal hazards and ecosystem functions potentially resulting in impacts to property values, infrastructure investment and insurance rates. The results and process presented here can be used as a guide for communities vulnerable to SLR to identify and prioritize adaptation strategies that slow and/or accommodate the changes underway.

  19. A modeling study of coastal inundation induced by storm surge, sea-level rise, and subsidence in the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhaoqing; Wang, Taiping; Leung, Lai-Yung R.; Hibbard, Kathleen A.; Janetos, Anthony C.; Kraucunas, Ian P.; Rice, Jennie S.; Preston, Benjamin; Wilbanks, Thomas

    2013-12-10

    The northern coasts of the Gulf of Mexico are highly vulnerable to the direct threats of climate change, such as hurricane-induced storm surge, and such risks can be potentially exacerbated by land subsidence and global sea level rise. This paper presents an application of a coastal storm surge model to study the coastal inundation process induced by tide and storm surge, and its response to the effects of land subsidence and sea level rise in the northern Gulf coast. An unstructured-grid Finite Volume Coastal Ocean Model was used to simulate tides and hurricane-induced storm surges in the Gulf of Mexico. Simulated distributions of co-amplitude and co-phase of semi-diurnal and diurnal tides are in good agreement with previous modeling studies. The storm surges induced by four historical hurricanes (Rita, Katrina, Ivan and Dolly) were simulated and compared to observed water levels at National Oceanic and Atmospheric Administration tide stations. Effects of coastal subsidence and future global sea level rise on coastal inundation in the Louisiana coast were evaluated using a parameter “change of inundation depth” through sensitivity simulations that were based on a projected future subsidence scenario and 1-m global sea level rise by the end of the century. Model results suggested that hurricane-induced storm surge height and coastal inundation could be exacerbated by future global sea level rise and subsidence, and that responses of storm surge and coastal inundation to the effects of sea level rise and subsidence are highly nonlinear and vary on temporal and spatial scales.

  20. Ice sheet systems and sea level change.

    Science.gov (United States)

    Rignot, E. J.

    2015-12-01

    Modern views of ice sheets provided by satellites, airborne surveys, in situ data and paleoclimate records while transformative of glaciology have not fundamentally changed concerns about ice sheet stability and collapse that emerged in the 1970's. Motivated by the desire to learn more about ice sheets using new technologies, we stumbled on an unexplored field of science and witnessed surprising changes before realizing that most were coming too fast, soon and large. Ice sheets are integrant part of the Earth system; they interact vigorously with the atmosphere and the oceans, yet most of this interaction is not part of current global climate models. Since we have never witnessed the collapse of a marine ice sheet, observations and exploration remain critical sentinels. At present, these observations suggest that Antarctica and Greenland have been launched into a path of multi-meter sea level rise caused by rapid climate warming. While the current loss of ice sheet mass to the ocean remains a trickle, every mm of sea level change will take centuries of climate reversal to get back, several major marine-terminating sectors have been pushed out of equilibrium, and ice shelves are irremediably being lost. As glaciers retreat from their salty, warm, oceanic margins, they will melt away and retreat slower, but concerns remain about sea level change from vastly marine-based sectors: 2-m sea level equivalent in Greenland and 23-m in Antarctica. Significant changes affect 2/4 marine-based sectors in Greenland - Jakobshavn Isb. and the northeast stream - with Petermann Gl. not far behind. Major changes have affected the Amundsen Sea sector of West Antarctica since the 1980s. Smaller yet significant changes affect the marine-based Wilkes Land sector of East Antarctica, a reminder that not all marine-based ice is in West Antarctica. Major advances in reducing uncertainties in sea level projections will require massive, interdisciplinary efforts that are not currently in place

  1. Contextualization of Holocene beach ridge systems for relative sea-level reconstruction using the SRTM elevation model

    Science.gov (United States)

    Sander, Lasse; Raniolo, Luís Ariel; Alberdi, Ernesto; Pejrup, Morten

    2014-05-01

    Beach ridge plains are a common feature of prograding coastlines and they have in the past been widely used as geomorphological archives for the reconstruction of past coastal dynamics, event chronologies or late quaternary sea-level change. The most critical parameters for sea-level related research are the consistent definition and confidence of information on surface elevation of the beach ridge deposits. In most parts of the world, the availability of high-resolution geodata is very limited. The measurement of e.g. high-precision GPS (Global Positioning System) data is costly, time-consuming and essentially of limited spatial coverage. The SRTM (Shuttle Radar Topography Mission) dataset is a freely-available digital surface model covering landmasses between approximately 60° N and 56° S at a 90 m (3 arc seconds) resolution. The model elevations are indicated without decimals (integer) and are projected for the WGS84 ellipsoid. On a beach ridge plain at Caleta de los Loros, Río Negro, Argentina, we observed a good correlation of GPS-RTK (GPS-Real Time Kinematic) measurements (estimated vertical accuracy: migration during the approx. 13 years between the date of SRTM data acquisition and our GPS measurement. This interpretation is supported by a multi-decadal sequence of Landsat false-color composites. Vegetation cover and rounding errors are further possible factors in explaining vertical deviation. The consistency of data quality was confirmed by a comparison study using a LiDAR (Light detection and ranging)-based digital elevation model (vertical accuracy: data in near-coastal environments is probably owed to the correction of the original dataset for a fixed value of 0 m along the coastlines of the world (SRTM Water Body Data). Our findings indicate that, at certain scales, a spatial integration of linear GPS data can be attempted using the SRTM dataset. However, the process must be aided by adequate surface information (e.g. Landsat images from close to

  2. Statistical modelling of monthly mean sea level at coastal tide gauge stations along the Indian subcontinent

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, K.; Das, V.K.; DineshKumar, P.K.

    on the west coast have shown minimum RMSEs for the corresponding coasts for all the three models, while Bhavnagar on west coast has shown very high RMSE values. The EWMA technique (which yields forecast with a lead time of only one month) gave the lowest root...

  3. Steric Sea Level Change in Twentieth Century Historical Climate Simulation and IPCC-RCP8.5 Scenario Projection: A Comparison of Two Versions of FGOALS Model

    Institute of Scientific and Technical Information of China (English)

    DONG Lu; ZHOU Tianjun

    2013-01-01

    To reveal the steric sea level change in 20th century historical climate simulations and future climate change projections under the IPCC's Representative Concentration Pathway 8.5 (RCP8.5) scenario,the results of two versions of LASG/IAP's Flexible Global Ocean-Atmosphere-Land System model (FGOALS) are analyzed.Both models reasonably reproduce the mean dynamic sea level features,with a spatial pattern correlation coefficient of 0.97 with the observation.Characteristics of steric sea level changes in the 20th century historical climate simulations and RCP8.5 scenario projections are investigated.The results show that,in the 20th century,negative trends covered most parts of the global ocean.Under the RCP8.5 scenario,global-averaged steric sea level exhibits a pronounced rising trend throughout the 21st century and the general rising trend appears in most parts of the global ocean.The magnitude of the changes in the 21st century is much larger than that in the 20th century.By the year 2100,the global-averaged steric sea level anomaly is 18 cm and 10 cm relative to the year 1850 in the second spectral version of FGOALS (FGOALS-s2) and the second grid-point version of FGOALS (FGOALS-g2),respectively.The separate contribution of the thermosteric and halosteric components from various ocean layers is further evaluated.In the 20th century,the steric sea level changes in FGOALS-s2 (FGOALS-g2) are largely attributed to the thermosteric (halosteric) component relative to the pre-industrial control run.In contrast,in the 21st century,the thermosteric component,mainly from the upper 1000 m,dominates the steric sea level change in both models under the RCP8.5 scenario.In addition,the steric sea level change in the marginal sea of China is attributed to the thermosteric component.

  4. 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 wi

  5. 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 21st 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 with

  6. Response of the North Atlantic dynamic sea level and circulation to Greenland meltwater and climate change in an eddy-permitting ocean model

    Science.gov (United States)

    Saenko, Oleg A.; Yang, Duo; Myers, Paul G.

    2016-12-01

    The response of the North Atlantic dynamic sea surface height (SSH) and ocean circulation to Greenland Ice Sheet (GrIS) meltwater fluxes is investigated using a high-resolution model. The model is forced with either present-day-like or projected warmer climate conditions. In general, the impact of meltwater on the North Atlantic SSH and ocean circulation depends on the surface climate. In the two major regions of deep water formation, the Labrador Sea and the Nordic Seas, the basin-mean SSH increases with the increase of the GrIS meltwater flux. This SSH increase correlates with the decline of the Atlantic meridional overturning circulation (AMOC). However, while in the Labrador Sea the warming forcing and GrIS meltwater input lead to sea level rise, in the Nordic Seas these two forcings have an opposite influence on the convective mixing and basin-mean SSH (relative to the global mean). The warming leads to less sea-ice cover in the Nordic Seas, which favours stronger surface heat loss and deep mixing, lowering the SSH and generally increasing the transport of the East Greenland Current. In the Labrador Sea, the increased SSH and weaker deep convection are reflected in the decreased transport of the Labrador Current (LC), which closes the subpolar gyre in the west. Among the two major components of the LC transport, the thermohaline and bottom transports, the former is less sensitive to the GrIS meltwater fluxes under the warmer climate. The SSH difference across the LC, which is a component of the bottom velocity, correlates with the long-term mean AMOC rate.

  7. The Adriatic Sea: A Long-Standing Laboratory for Sea Level Studies

    Science.gov (United States)

    Vilibić, Ivica; Šepić, Jadranka; Pasarić, Mira; Orlić, Mirko

    2017-07-01

    The paper provides a comprehensive review of all aspects of Adriatic Sea level research covered by the literature. It discusses changes occurring over millennial timescales and documented by a variety of natural and man-made proxies and post-glacial rebound models; mean sea level changes occurring over centennial to annual timescales and measured by modern instruments; and daily and higher-frequency changes (with periods ranging from minutes to a day) that are contributing to sea level extremes and are relevant for present-day flooding of coastal areas. Special tribute is paid to the historic sea level studies that shaped modern sea level research in the Adriatic, followed by a discussion of existing in situ and remote sensing observing systems operating in the Adriatic area, operational forecasting systems for Adriatic storm surges, as well as warning systems for tsunamis and meteotsunamis. Projections and predictions of sea level and related hazards are also included in the review. Based on this review, open issues and research gaps in the Adriatic Sea level studies are identified, as well as the additional research efforts needed to fill the gaps. The Adriatic Sea, thus, remains a laboratory for coastal sea level studies for semi-enclosed, coastal and marginal seas in the world ocean.

  8. An assessment of uncertainties in using volume-area modelling for computing the twenty-first century glacier contribution to sea-level change

    NARCIS (Netherlands)

    Slangen, A.B.A.; van de Wal, R.S.W.

    2011-01-01

    A large part of present-day sea-level change is formed by the melt of glaciers and ice caps (GIC). This study focuses on the uncertainties in the calculation of the GIC contribution on a century timescale. The model used is based on volume-area scaling, 5 combined with the mass balance sensitivity o

  9. 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 du

  10. 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 factors in

  11. 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

  12. 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.

  13. Arctic Sea Level During the Satellite Altimetry Era

    Science.gov (United States)

    Carret, A.; Johannessen, J. A.; Andersen, O. B.; Ablain, M.; Prandi, P.; Blazquez, A.; Cazenave, A.

    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 from the ORAP5 reanalysis, and Gravity Recovery And Climate Experiment (GRACE) space gravimetry data to estimate the steric and mass components. Regional sea-level trends seen in the altimetry map, in particular over the Beaufort Gyre and along the eastern coast of Greenland, are of halosteric origin. 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 climate models from the CMIP5 project are also used. The models lead us to the same conclusions concerning the halosteric origin of the trend patterns.

  14. Arctic Sea Level During the Satellite Altimetry Era

    Science.gov (United States)

    Carret, A.; Johannessen, J. A.; Andersen, O. B.; Ablain, M.; Prandi, P.; Blazquez, A.; Cazenave, A.

    2016-11-01

    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 from the ORAP5 reanalysis, and Gravity Recovery And Climate Experiment (GRACE) space gravimetry data to estimate the steric and mass components. Regional sea-level trends seen in the altimetry map, in particular over the Beaufort Gyre and along the eastern coast of Greenland, are of halosteric origin. 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 climate models from the CMIP5 project are also used. The models lead us to the same conclusions concerning the halosteric origin of the trend patterns.

  15. Dynamic sea level changes following changes in the thermohaline circulation

    OpenAIRE

    Levermann, Anders; Griesel, Alexa; Hofmann, Matthias; Montoya Redondo, María Luisa; Rahmstorf, Stefan

    2005-01-01

    Using the coupled climate model CLIMBER-3a, we investigate changes in sea surface elevation due to a weakening of the thermohaline circulation (THC). In addition to a global sea level rise due to a warming of the deep sea, this leads to a regional dynamic sea level change which follows quasi-instantaneously any change in the ocean circulation. We show that the magnitude of this dynamic effect can locally reach up to ~1m, depending on the initial THC strength. In some regions the rate of chang...

  16. 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 (Holocene sea-level indicators and the other of published, modern growth rates, abundance and coverage of mangrove and coral species for 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.

  17. Inception of a global atlas of Holocene sea levels

    Science.gov (United States)

    Khan, Nicole; Rovere, Alessio; Engelhart, Simon; Horton, Benjamin

    2017-04-01

    Determining the rates, mechanisms and geographic variability of sea-level change is a priority science question for the next decade of ocean research. To address these research priorities, the HOLocene SEA-level variability (HOLSEA) working group is developing the first standardized global synthesis of Holocene relative sea-level data to: (1) estimate the magnitudes and rates of global mean sea-level change during the Holocene; and (2) identify trends in spatial variability and decipher the processes responsible for geographic differences in relative sea-level change. Here we present the preliminary efforts of the working group to compile the database, which includes sea-level index points and limiting data from a range of different indicators across seven continents from the Last Glacial Maximum to present. We follow a standard protocol that incorporates full consideration of vertical and temporal uncertainty for each sea-level index point, including uncertainties associated with the relationship of each indicator to past sea-level and the methods used to date each indicator. We describe the composition of the global database, identify gaps in data availability, and highlight our effort to create an online platform to access the data. These data will be made available in a special issue of Quaternary Science Reviews and archived on NOAA's National Centers for Environmental Information (NCEI) in early 2018. We also invite researchers who collect or model Holocene sea-level data to participate. Long-term, this effort will enhance predictions of 21st century sea-level rise, and provide a vital contribution to the assessment of natural hazards with respect to sea-level rise and coastal response.

  18. Wave transformation across coral reefs under changing sea levels

    Science.gov (United States)

    Harris, Daniel; Power, Hannah; Vila-Conejo, Ana; Webster, Jody

    2015-04-01

    The transformation of swell waves from deep water across reef flats is the primary process regulating energy regimes in coral reef systems. Coral reefs are effective barriers removing up to 99% of wave energy during breaking and propagation across reef flats. Consequently back-reef environments are often considered low energy with only limited sediment transport and geomorphic change during modal conditions. Coral reefs, and specifically reef flats, therefore provide important protection to tropical coastlines from coastal erosion and recession. However, changes in sea level could lead to significant changes in the dissipation of swell wave energy in coral reef systems with wave heights dependent on the depth over the reef flat. This suggests that a rise in sea level would also lead to significantly higher energy conditions exacerbating the transgressive effects of sea level rise on tropical beaches and reef islands. This study examines the potential implications of different sea level scenarios on the transformation of waves across the windward reef flats of One Tree Reef, southern Great Barrier Reef. Waves were measured on the reef flats and back-reef sand apron of One Tree Reef. A one-dimensional wave model was calibrated and used to investigate wave processes on the reef flats under different mean sea level (MSL) scenarios (present MSL, +1 m MSL, and +2 m MSL). These scenarios represent both potential future sea level states and also the paleo sea level of the late Holocene in the southern Great Barrier Reef. Wave heights were shown to increase under sea level rise, with greater wave induced orbital velocities affecting the bed under higher sea levels. In general waves were more likely to entrain and transport sediment both on the reef flat and in the back reef environment under higher sea levels which has implications for not only forecasted climate change scenarios but also for interpreting geological changes during the late Holocene when sea levels were 1

  19. Estimating Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

    Directory of Open Access Journals (Sweden)

    X. Fettweis

    2012-08-01

    Full Text Available We report future projections of Surface Mass Balance (SMB over the Greenland ice sheet (GrIS obtained with the regional climate model MAR, forced by the outputs of three CMIP5 General Circulation Models (GCMs when considering two different warming scenarios (RCP 4.5 and RCP 8.5. The GCMs selected in this study have been chosen according to their ability to simulate the current climate over Greenland. Our results indicate that in a warmer climate (i the mass gained due to increased precipitation over GrIS does not compensate the mass lost through increased run-off; (ii the surface melt increases non-linearly with rising temperatures due to the positive feedback between surface albedo and melt, associated with the expansion of bare ice zones which, in addition, decreases the ice sheet refreezing capacity; (iii most of the precipitation is expected to fall as rainfall in summer, which further increases surface melt; (iv no considerable change is expected on the length of the melting season, since heavier winter snowfall dampens the melt increase at the end of spring; (v the increase of meltwater run-off versus temperature anomalies is dependent of the GCM-forced MAR ability to simulate the current climate; (vi the MAR-simulated SMB changes can be approximated using the annual accumulated snowfall and summer 600 hPa temperature increase simulated by the forcing GCMs. In view of the large range in the CMIP5 future projections for the same future scenario, the GCM-based SMB approximations allow us to estimate what future projections are most likely within the CMIP5 multi-model ensemble. In 2100, the ensemble mean projects a sea level rise, resulting from a GrIS SMB decrease, estimated to be +4 ± 2 cm and +9 ± 4 cm for the RCP 4.5 and RCP 8.5 scenarios, respectively. The GrIS SMB should remain positive with respect to RCP 4.5 scenario and becomes negative around 2070 in the case of the RCP 8.5 scenario since a global warming >+3 °C is needed

  20. Monitoring and modeling of contaminant loads and levels in Norwegian sea 2011; Tilfoerselsprogrammet 2011. Overvaakingav tilfoersler og miljoetilstand i Norskehavet

    Energy Technology Data Exchange (ETDEWEB)

    Green, Norman W.; Heldal, Hilde Elise; Maage, Amund; Aas, Wenche; Graefert, Torbjoern; Schrum, Corinna; Boitsov, Stepan; Breivik, Knut; Iosjpe, Mikhail; Yakushev, Evgeniy; Skogen, Morten; Hoegaasen, Tore; Eckhardt, Sabine; Christiansen, Anne Bjoerkenes; Daae, Kjersti L.; Durand, Dominique; Ledang, Anna Birgitta; Jaccard, Pierre Francois

    2012-07-01

    This report describes the calculation of the supply of oil, hazardous chemicals and radioactive substances from seven sources of seven regions in the Norwegian part of the Norwegian Sea. The data from the various sources used to calculate the concentrations of pollutants in the water column throughout the defined area of the Norwegian Sea (3 dimensions) and calculate the transport of Hg, PCB153 and BaP in and out of each of the seven regions. This transport flux is huge compared with inputs and will alternately be a net source or net sink of each region. The main feature is that the supply is dominated by the fallout from the atmosphere is balanced by decomposition and sedimentation in the water column plus exports / imports from adjacent waters. It is relatively small supply of hazardous substances. With few exceptions, for the supply of air the biggest contribution of mercury, lead, cadmium, chromium, arsenic, PCBs (PCB-153) and PAH (benzo [a] pyrene) to all regions. Exception contributions of land for chromium in mid-Norway and contributions from seabed for lead and chromium from more central parts of the Norwegian Sea. Ship traffic dominates regard. supply of oil. Supply air from the major contribution of radionuclides plutonium-239 240 and strontium-90 in the eastern part of the Norwegian Sea. Otherwise, Sellafield is the dominant source. Contaminants in sediment and cod were largely of low to moderate concentrations. The concentration of radioactive substances in water, sediment and cod were low and comparable with results from other studies in the Norwegian Sea. There are still large gaps in knowledge and uncertainties in both the data and the estimates of supplies. It is especially important to improved figures for inflows into the oceans via air and enhancement of the marine transport and dispersion models.(eb)

  1. The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) contribution to CMIP6: investigation of sea-level and ocean climate change in response to CO2 forcing

    Science.gov (United States)

    Gregory, Jonathan M.; Bouttes, Nathaelle; Griffies, Stephen M.; Haak, Helmuth; Hurlin, William J.; Jungclaus, Johann; Kelley, Maxwell; Lee, Warren G.; Marshall, John; Romanou, Anastasia; Saenko, Oleg A.; Stammer, Detlef; Winton, Michael

    2016-11-01

    The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) aims to investigate the spread in simulations of sea-level and ocean climate change in response to CO2 forcing by atmosphere-ocean general circulation models (AOGCMs). It is particularly motivated by the uncertainties in projections of ocean heat uptake, global-mean sea-level rise due to thermal expansion and the geographical patterns of sea-level change due to ocean density and circulation change. FAFMIP has three tier-1 experiments, in which prescribed surface flux perturbations of momentum, heat and freshwater respectively are applied to the ocean in separate AOGCM simulations. All other conditions are as in the pre-industrial control. The prescribed fields are typical of pattern and magnitude of changes in these fluxes projected by AOGCMs for doubled CO2 concentration. Five groups have tested the experimental design with existing AOGCMs. Their results show diversity in the pattern and magnitude of changes, with some common qualitative features. Heat and water flux perturbation cause the dipole in sea-level change in the North Atlantic, while momentum and heat flux perturbation cause the gradient across the Antarctic Circumpolar Current. The Atlantic meridional overturning circulation (AMOC) declines in response to the heat flux perturbation, and there is a strong positive feedback on this effect due to the consequent cooling of sea-surface temperature in the North Atlantic, which enhances the local heat input to the ocean. The momentum and water flux perturbations do not substantially affect the AMOC. Heat is taken up largely as a passive tracer in the Southern Ocean, which is the region of greatest heat input, while the weakening of the AMOC causes redistribution of heat towards lower latitudes. Future analysis of these and other phenomena with the wider range of CMIP6 FAFMIP AOGCMs will benefit from new diagnostics of temperature and salinity tendencies, which will enable investigation of the

  2. 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...

  3. Glacial Isostatic Adjustment and Contemporary Sea Level Rise: An Overview

    Science.gov (United States)

    Spada, Giorgio

    2017-01-01

    Glacial isostatic adjustment (GIA) encompasses a suite of geophysical phenomena accompanying the waxing and waning of continental-scale ice sheets. These involve the solid Earth, the oceans and the cryosphere both on short (decade to century) and on long (millennia) timescales. In the framework of contemporary sea-level change, the role of GIA is particular. In fact, among the processes significantly contributing to contemporary sea-level change, GIA is the only one for which deformational, gravitational and rotational effects are simultaneously operating, and for which the rheology of the solid Earth is essential. Here, I review the basic elements of the GIA theory, emphasizing the connections with current sea-level changes observed by tide gauges and altimetry. This purpose is met discussing the nature of the "sea-level equation" (SLE), which represents the basis for modeling the sea-level variations of glacial isostatic origin, also giving access to a full set of geodetic variations associated with GIA. Here, the SLE is employed to characterize the remarkable geographical variability of the GIA-induced sea-level variations, which are often expressed in terms of "fingerprints". Using harmonic analysis, the spatial variability of the GIA fingerprints is compared to that of other components of contemporary sea-level change. In closing, some attention is devoted to the importance of the "GIA corrections" in the context of modern sea-level observations, based on tide gauges or satellite altimeters.

  4. Glacial Isostatic Adjustment and Contemporary Sea Level Rise: An Overview

    Science.gov (United States)

    Spada, Giorgio

    2016-08-01

    Glacial isostatic adjustment (GIA) encompasses a suite of geophysical phenomena accompanying the waxing and waning of continental-scale ice sheets. These involve the solid Earth, the oceans and the cryosphere both on short (decade to century) and on long (millennia) timescales. In the framework of contemporary sea-level change, the role of GIA is particular. In fact, among the processes significantly contributing to contemporary sea-level change, GIA is the only one for which deformational, gravitational and rotational effects are simultaneously operating, and for which the rheology of the solid Earth is essential. Here, I review the basic elements of the GIA theory, emphasizing the connections with current sea-level changes observed by tide gauges and altimetry. This purpose is met discussing the nature of the "sea-level equation" (SLE), which represents the basis for modeling the sea-level variations of glacial isostatic origin, also giving access to a full set of geodetic variations associated with GIA. Here, the SLE is employed to characterize the remarkable geographical variability of the GIA-induced sea-level variations, which are often expressed in terms of "fingerprints". Using harmonic analysis, the spatial variability of the GIA fingerprints is compared to that of other components of contemporary sea-level change. In closing, some attention is devoted to the importance of the "GIA corrections" in the context of modern sea-level observations, based on tide gauges or satellite altimeters.

  5. Automated system for near-real time modelling and prediction of altimeter-derived sea level anomalies

    Science.gov (United States)

    Niedzielski, Tomasz; Miziński, Bartłomiej

    2013-08-01

    This paper serves as a presentation of a novel geoinformation system and a dedicated service, jointly named as Prognocean and based at the University of Wrocław (Poland), that aim to predict Sea Level Anomaly (SLA) maps and publish them online. The system works in near-real time and is updated daily. The data are provided by the Archiving, Validation and Interpretation of Satellite Oceanographic data (AVISO), and the time series processed by Prognocean is delivered by various altimetric satellites. The emphasis is put on gridded SLA maps, also known as MSLA, which are provided as Delayed Time (DT) and Near-Real Time (NRT) daily products. The daily sampling interval, however, does not coincide with typical repeat cycles of altimetric satellites and is obtained through reprocessing produced by AVISO. The two-module infrastructure forms the system. The first module is responsible for the near-real time communication with AVISO to download the most recent MSLA data and acquire the corrected data when the geophysical corrections have been available. The second module forms the main engine which does data processing, modelling, forecasting, statistical quality control and finally generates products as maps. The online service, however, publishes the products online every day. The above-mentioned components and infrastructure are described in detail. The performance of the system was evaluated using at least 150 predicted MSLA maps, available after half year of computations carried out in near-real time. We identified a few regions of imperfect performance of our prognoses and found that they spatially correspond to the mouth of the Amazon River and locations of key mesoscale eddies, the vast majority of which being nonlinear and hence unmodelled in our experiment.

  6. Global Sea Level Change and Thermal Contribution

    Institute of Scientific and Technical Information of China (English)

    ZUO Juncheng; ZHANG Jianli; DU Ling; LI Peiliang; LI Lei

    2009-01-01

    The global long-term sea level trend is obtained from the analysis of tide gauge data and TOPEX/Poseidon data. The linear trend of global mean sea level is highly non-umiform spatially, with an average rate of 2.2 mm year-1 in T/P sea-level rise from October 1992 to September 2002. Sea level change duc to temperature vanation (the thermosteric sea level) is discussed. The results are compared with TOPEX/Poseidon altimeter data in the same temporal span at different spatial scales. It is indicated that the ther-mal effect accounts for 86% and 73% of the observed seasonal variability in the northern and southern hemispheres, respectively. The TOPEX/Poseidon observed sea level lags behind the TSI, by 2 months in the zonal band of 40°-60° in both the northern and southern hemispheres. Systematic differences of about 1-2cm between TOPEX/Poseidon observations and thermosteric sea level data are obtained. The potential causes for these differences include water exchange among the atmosphere, land, and oceans, and some pos-sible deviations in thermosteric contribution estimates and geophysical corrections to the TOPEX/Poseidon data.

  7. Hölder Scales of Sea Level

    Directory of Open Access Journals (Sweden)

    Ming Li

    2012-01-01

    Full Text Available The statistics of sea level is essential in the field of geosciences, ranging from ocean dynamics to climates. The fractal properties of sea level, such as long-range dependence (LRD or long memory, 1/f noise behavior, and self-similarity (SS, are known. However, the description of its multiscale behavior as well as local roughness with the Hölder exponent h(t from a view of multifractional Brownian motion (mBm is rarely reported, to the best of our knowledge. In this research, we will exhibit that there is the multiscale property of sea level based on h(ts of sea level data recorded by the National Data Buoy Center (NDBC at six stations in the Florida and Eastern Gulf of Mexico. The contributions of this paper are twofold as follows. (i Hölder exponent of sea level may not change with time considerably at small time scale, for example, daily time scale, but it varies significantly at large time scale, such as at monthly time scale. (ii The dispersion of the Hölder exponents of sea level may be different at different stations. This implies that the Hölder roughness of sea level may be spatial dependent.

  8. Sea Level Rise Projections for DSL-SAMBI

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is output from the Sea Level Affecting Marshes Model (SLAMM) for the South Atlantic Migratory Bird Initiative (SAMBI) geographic planning region. It...

  9. Sea modeling and rendering

    Science.gov (United States)

    Cathala, Thierry; Latger, Jean

    2010-10-01

    More and more defence and civil applications require simulation of marine synthetic environment. Currently, the "Future Anti-Surface-Guided-Weapon" (FASGW) or "anti-navire léger" (ANL) missile needs this kind of modelling. This paper presents a set of technical enhancement of the SE-Workbench that aim at better representing the sea profile and the interaction with targets. The operational scenario variability is a key criterion: the generic geographical area (e.g. Persian Gulf, coast of Somalia,...), the type of situation (e.g. peace keeping, peace enforcement, anti-piracy, drug interdiction,...)., the objectives (political, strategic, or military objectives), the description of the mission(s) (e.g. antipiracy) and operation(s) (e.g. surveillance and reconnaissance, escort, convoying) to achieve the objectives, the type of environment (Weather, Time of day, Geography [coastlines, islands, hills/mountains]). The paper insists on several points such as the dual rendering using either ray tracing [and the GP GPU optimization] or rasterization [and GPU shaders optimization], the modelling of sea-surface based on hypertextures and shaders, the wakes modelling, the buoyancy models for targets, the interaction of coast and littoral, the dielectric infrared modelling of water material.

  10. Modelling sea ice dynamics

    Science.gov (United States)

    Murawski, Jens; Kleine, Eckhard

    2017-04-01

    Sea ice remains one of the frontiers of ocean modelling and is of vital importance for the correct forecasts of the northern oceans. At large scale, it is commonly considered a continuous medium whose dynamics is modelled in terms of continuum mechanics. Its specifics are a matter of constitutive behaviour which may be characterised as rigid-plastic. The new developed sea ice dynamic module bases on general principles and follows a systematic approach to the problem. Both drift field and stress field are modelled by a variational property. Rigidity is treated by Lagrangian relaxation. Thus one is led to a sensible numerical method. Modelling fast ice remains to be a challenge. It is understood that ridging and the formation of grounded ice keels plays a role in the process. The ice dynamic model includes a parameterisation of the stress associated with grounded ice keels. Shear against the grounded bottom contact might lead to plastic deformation and the loss of integrity. The numerical scheme involves a potentially large system of linear equations which is solved by pre-conditioned iteration. The entire algorithm consists of several components which result from decomposing the problem. The algorithm has been implemented and tested in practice.

  11. Explaining trends and variability in coastal relative sea level

    Science.gov (United States)

    Frederikse, Thomas; Riva, Riccardo

    2016-04-01

    Comprehensive understanding of trends and variability in coastal mean sea level is vital for protecting shores under a changing climate. To understand the behavior of coastal relative sea level (RSL), it is crucial to identify all relevant processes. We combine data from various geophysical models and observations to determine whether the trends and decadal variability observed in relative sea level at tide gauges can be explained by the sum of all known contributors. A key contributor to RSL is vertical land motion, which is caused by glacial isostatic adjustment (GIA), solid earth response to surface loading, tectonics, and local effects. We explicitly model low-frequency loading effects to correct GPS records, which leads to a more consistent trend than only using GIA models. Secondly, we create sea level fingerprints based on estimates of ice melt and changes in land hydrology, which provide the RSL contribution due to large-scale mass transport. Since coastal areas are often located on shallow continental shelves, steric effects will generally be small, and a large fraction of the decadal sea level variability will have a remote steric origin. Therefore, we determine a relation between coastal sea level and deep sea steric variability. For the period 1950-2012, we find that for many locations, including the European coast, the observed and modeled RSL time series agree well on decadal and secular scales.

  12. Seasonal variability in the Baltic Sea level

    Directory of Open Access Journals (Sweden)

    Marek Świrgoń

    2013-11-01

    Full Text Available Sea level is subject to spatial and temporal variability on different scales. In this paper we investigate seasonal variability in the open Baltic Sea level using daily satellite altimetry data for the period 1 January 1993-31 December 2010. Our results indicate that there is a well-pronounced seasonal cycle in the 18-year average sea level and in its standard deviation. The average annual SLA amplitude in the open Baltic Sea is about 18 cm. The seasonal cycle of the SLA in the Baltic Sea is asymmetric in shape. In the autumn and winter (about 240-260 days per year, the 18-year average daily SLA are higher than the 18-year annual average SLA. In the spring and summer (about 100-120 days per year, the 18-year average daily SLA are lower than the 18-year annual average SLA. A similar asymmetry of the seasonal cycle is not observed in the North Sea and North Atlantic SLA data. The annual pattern of the sea level variability in the Baltic Sea is evident if one considers multi-year average time series, but the cycle can be obscured in some years.

  13. Can the Gulf Stream induce coherent short-term fluctuations in sea level along the US East Coast? A modeling study

    Science.gov (United States)

    Ezer, Tal

    2016-02-01

    Much attention has been given in recent years to observations and models that show that variations in the transport of the Atlantic Meridional Overturning Circulation (AMOC) and in the Gulf Stream (GS) can contribute to interannual, decadal, and multi-decadal variations in coastal sea level (CSL) along the US East Coast. However, less is known about the impact of short-term (time scales of days to weeks) fluctuations in the GS and their impact on CSL anomalies. Some observations suggest that these anomalies can cause unpredictable minor tidal flooding in low-lying areas when the GS suddenly weakens. Can these short-term CSL variations be attributed to changes in the transport of the GS? An idealized numerical model of the GS has been set up to test this proposition. The regional model uses a 1/12° grid with a simplified coastline to eliminate impacts from estuaries and small-scale coastal features and thus isolate the GS impact. The GS in the model is driven by inflows/outflows, representing the Florida Current (FC), the Slope Current (SC), and the Sargasso Sea (SS) flows. Forcing the model with an oscillatory FC transport with a period of 2, 5, and 10 days produced coherent CSL variations from Florida to the Gulf of Maine with similar periods. However, when imposing variations in the transports of the SC or the SS, they induce CSL variations only north of Cape Hatteras. The suggested mechanism is that variations in GS transport produce variations in sea level gradient across the entire GS length and this large-scale signal is then transmitted into the shelf by the generation of coastal-trapped waves (CTW). In this idealized model, the CSL variations induced by variations of ˜10 Sv in the transport of the GS are found to resemble CSL variations induced by ˜5 m s-1 zonal wind fluctuations, though the mechanisms of wind-driven and GS-driven sea level are quite different. Better understanding of the relation between variations in offshore currents and CSL will help

  14. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    Directory of Open Access Journals (Sweden)

    R. A. Ibrayev

    2010-03-01

    Full Text Available A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. The model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  15. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    Directory of Open Access Journals (Sweden)

    R. A. Ibrayev

    2009-09-01

    Full Text Available A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December–January; Eckman south-, south-westward drift in February–July embedded by western and eastern southward coastal currents and transition type in August–November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. Model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  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; 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.

  17. Effect of Sea Level Variation on Tidal Characteristic Values for the East China Sea

    Institute of Scientific and Technical Information of China (English)

    于宜法; 俞聿修; 左军成; 万振文; 陈宗镛

    2003-01-01

    Tidal waves in the East China Sea are simulated numerically with POM(Princeton Ocean Model) model for normal mean sea level, 30 cm higher, 60 cm higher, and 100 cm higher, respectively, and the simulated result is compared with the harmonic analysis result of hourly sea level data from 19 tide gauges for more than 19 years. It is indicated that the long-term mean sea level variation affects notably tidal waves in this region. Generally, the tidal amplitude increases when the mean sea level rises, but this relationship may be inverse for some sea areas. The maximal variation of tidal amplitude takes place in the zones near the Fujian coast and the Zhejiang coast, rather than the shallowest Bohai Sea. The maximum increase of M2 amplitude can exceed about 15 cm corresponding to the 60 cm rise of the mean sea level along the Fujian coast. The other regions with large variations of tidal amplitude are those along the Jiangsu coast, the south-east coast of Shandong, and the south-east coast of Dalian. The propagation of tidal waves is also related to mean sea level variation, and the tidal phase-lag decreases generally when the mean sea level rises. Almost all the regions where the tidal phase-lag increases with rising mean sea level are close to amphidromic points, meanwhile the spatial area of such regions is very small. Because the influence of mean sea level variation upon tidal waves is spatially marked, such spatial effect should be considered in calculation of the tidal characteristic value and engineering water level. In the region where the amplitudes of the major tidal constituents increase, the probable maximum high water level becomes higher, the probable maximum low water level becomes lower, and both design water level andcheck water level increase obviously. For example, the design water level at Xiamen increases by 13.5 cm due to the variation of tidal waves when the mean sea level rises 60 cm, the total increase of design water level being 73.5 cm.

  18. Emulation of the MBM-MEDUSA model: exploring the sea level and the basin-to-shelf transfer influence on the system dynamics

    Science.gov (United States)

    Ermakov, Ilya; Crucifix, Michel; Munhoven, Guy

    2013-04-01

    Complex climate models require high computational burden. However, computational limitations may be avoided by using emulators. In this work we present several approaches for dynamical emulation (also called metamodelling) of the Multi-Box Model (MBM) coupled to the Model of Early Diagenesis in the Upper Sediment A (MEDUSA) that simulates the carbon cycle of the ocean and atmosphere [1]. We consider two experiments performed on the MBM-MEDUSA that explore the Basin-to-Shelf Transfer (BST) dynamics. In both experiments the sea level is varied according to a paleo sea level reconstruction. Such experiments are interesting because the BST is an important cause of the CO2 variation and the dynamics is potentially nonlinear. The output that we are interested in is the variation of the carbon dioxide partial pressure in the atmosphere over the Pleistocene. The first experiment considers that the BST is fixed constant during the simulation. In the second experiment the BST is interactively adjusted according to the sea level, since the sea level is the primary control of the growth and decay of coral reefs and other shelf carbon reservoirs. The main aim of the present contribution is to create a metamodel of the MBM-MEDUSA using the Dynamic Emulation Modelling methodology [2] and compare the results obtained using linear and non-linear methods. The first step in the emulation methodology used in this work is to identify the structure of the metamodel. In order to select an optimal approach for emulation we compare the results of identification obtained by the simple linear and more complex nonlinear models. In order to identify the metamodel in the first experiment the simple linear regression and the least-squares method is sufficient to obtain a 99,9% fit between the temporal outputs of the model and the metamodel. For the second experiment the MBM's output is highly nonlinear. In this case we apply nonlinear models, such as, NARX, Hammerstein model, and an 'ad

  19. Upper Limit for Sea Level Projections by 2100

    Science.gov (United States)

    Jevrejeva, Svetlana; Grinsted, Aslak; Moore, John

    2015-04-01

    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. We construct the probability density function of global sea level at 2100, estimating that sea level rises larger than 180 cm are less than 5% probable. An upper limit for global sea level rise of 190 cm is assembled by summing the highest estimates of individual sea level rise components simulated by process based models with the RCP8.5 scenario. The agreement between the methods may suggest more confidence than is warranted since large uncertainties remain due to the lack of scenario-dependent projections from ice sheet dynamical models, particularly for mass loss from marine-based fast flowing outlet glaciers in Antarctica.

  20. Legacy HMSRP NWHI Sea Level Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Island elevation data use in publication by Baker JD, Littnan CL, Johnston DW. "2006. Potential effects of sea level rise on the terrestrial habitats of endangered...

  1. Climate Prediction Center Darwin Sea Level Pressure

    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 Darwin sea level pressures and anomalies during 1951-present. The anomalies are departures...

  2. Sea level rise and its coastal impacts

    OpenAIRE

    Cazenave, Anny; Le Cozannet, Gonéri

    2014-01-01

    Link to the paper: http://onlinelibrary.wiley.com/doi/10.1002/2013EF000188/abstract; International audience; Global warming in response to accumulation of human-induced greenhouse gases inside the atmosphere has already caused several visible consequences, among them increase of the Earth's mean temperature and ocean heat content, melting of glaciers, and loss of ice from the Greenland and Antarctica ice sheets. Ocean warming and land ice melt in turn are causing sea level to rise. Sea level ...

  3. Observations: Oceanic climate change and sea level

    Digital Repository Service at National Institute of Oceanography (India)

    Bindoff, N.L.; Willebrand, J.; Artale, V.; Cazenave, A.; Gregory, J.; Gulev, S.; Hanawa, K.; LeQuere, C.; Levitus, S.; Nojiri, Y.; Shum, C.K.; Talley, L.D.; Unnikrishnan, A.S.

    Rising? ............................................ 409 References ........................................................................ 422 Appendix 5.A: Techniques, Error Estimation and Measurement Systems ................. 429 387... driven by reduced rates of water renewal, in the thermocline (~100–1,000 m) in most ocean basins from the early 1970s to the late 1990s. • Global mean sea level has been rising. From 1961 to 2003, the average rate of sea level rise was 1.8 ± 0.5 mm...

  4. Quantifying Population-Level Risks Using an Individual-Based Model: Sea Otters, Harlequin Ducks, and the Exxon Valdez Oil Spill

    OpenAIRE

    Harwell, Mark A.; JOHN H. GENTILE; Parker, Keith R.

    2012-01-01

    Ecological risk assessments need to advance beyond evaluating risks to individuals that are largely based on toxicity studies conducted on a few species under laboratory conditions, to assessing population-level risks to the environment, including considerations of variability and uncertainty. Two individual-based models (IBMs), recently developed to assess current risks to sea otters and seaducks in Prince William Sound more than 2 decades after the Exxon Valdez oil spill (EVOS), are used to...

  5. Dynamic sea level changes following changes in the thermohaline circulation

    CERN Document Server

    Levermann, A; Hofmann, M; Montoya, M; Rahmstorf, S; Levermann, Anders; Griesel, Alexa; Hofmann, Matthias; Montoya, Marisa; Rahmstorf, Stefan

    2004-01-01

    Using the coupled climate model CLIMBER-3a, we investigate changes in sea surface elevation due to a weakening of the thermohaline circulation (THC). In addition to a global sea level rise due to a warming of the deep sea, this leads to a regional dynamic sea level change which follows quasi-instantaneously any change in the ocean circulation. We show that the magnitude of this dynamic effect can locally reach up to ~1m, depending on the initial THC strength. In some regions the rate of change can be up to 20-25 mm/yr. The emerging patterns are discussed with respect to the oceanic circulation changes. Most prominent is a south-north gradient reflecting the changes in geostrophic surface currents. Our results suggest that an analysis of observed sea level change patterns could be useful for monitoring the THC strength.

  6. Differences between mean tide level and mean sea level

    Science.gov (United States)

    Woodworth, P. L.

    2016-07-01

    This paper discusses the differences between mean tide level (MTL) and mean sea level (MSL) as demonstrated using information from a global tide gauge data set. The roles of the two main contributors to differences between MTL and MSL (the M4 harmonic of the M2 semidiurnal tide, and the combination of the diurnal tides K1 and O1) are described, with a particular focus on the spatial scales of variation in MTL-MSL due to each contributor. Findings from the tide gauge data set are contrasted with those from a state-of-the-art global tide model. The study is of interest within tidal science, but also has practical importance regarding the type of mean level used to define land survey datums. In addition, an appreciation of MTL-MSL difference is important in the use of the historical sea level data used in climate change research, with implications for some of the data stored in international databanks. Particular studies are made of how MTL and MSL might differ through the year, and if MTL is measured in daylight hours only, as has been the practice of some national geodetic agencies on occasions in the past.

  7. Differences between mean tide level and mean sea level

    Science.gov (United States)

    Woodworth, P. L.

    2017-01-01

    This paper discusses the differences between mean tide level (MTL) and mean sea level (MSL) as demonstrated using information from a global tide gauge data set. The roles of the two main contributors to differences between MTL and MSL (the M4 harmonic of the M2 semidiurnal tide, and the combination of the diurnal tides K1 and O1) are described, with a particular focus on the spatial scales of variation in MTL-MSL due to each contributor. Findings from the tide gauge data set are contrasted with those from a state-of-the-art global tide model. The study is of interest within tidal science, but also has practical importance regarding the type of mean level used to define land survey datums. In addition, an appreciation of MTL-MSL difference is important in the use of the historical sea level data used in climate change research, with implications for some of the data stored in international databanks. Particular studies are made of how MTL and MSL might differ through the year, and if MTL is measured in daylight hours only, as has been the practice of some national geodetic agencies on occasions in the past.

  8. Impact of global ocean model resolution on sea-level variability with emphasis on interannual time scales

    Directory of Open Access Journals (Sweden)

    T. Penduff

    2010-02-01

    Full Text Available Four global ocean/sea-ice simulations driven by the same realistic 47-year daily atmospheric forcing were performed by the DRAKKAR group at 2°, 1°, ½°, and ¼° resolutions. Simulated mean sea-surface heights (MSSH and sea-level anomalies (SLA are collocated over the period 1993–2004 onto the AVISO dataset. MSSH fields are compared with an inverse estimate. SLA datasets are filtered and compared over various time and space scales with AVISO regarding three characteristics: SLA standard deviations, spatial correlations between SLA variability maps, and temporal correlations between observed and simulated band-passed filtered local SLA timeseries. Beyond the 2°−1° transition whose benefits are moderate, further increases in resolution and associated changes in subgrid scale parameterizations simultaneously induce (i strong increases in SLA standard deviations, (ii strong improvements in the spatial distribution of SLA variability, and (iii slight decreases in temporal correlations between observed and simulation SLA timeseries. These 3 effects are not only clear on mesoscale (14–180 days and quasi-annual (5–18 months fluctuations, but also on the slower (interannual, large-scale variability ultimately involved in ocean-atmosphere coupled processes. Most SLA characteristics are monotonically affected by successive resolution increases, but irregularly and with a strong dependance on frequency and latitude. Benefits of enhanced resolution are greatest in the 1°−½° and ½°−¼° transitions, in the 14–180 day range, and within eddy-active mid- and high-latitude regions. In the real ocean, most eddy-active areas are characterized by a strong SLA variability at all timescales considered here; this localized, broad-banded temporal variability is only captured at ¼° resolution.

  9. 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.

  10. Tritium level along Romanian Black Sea Coast

    Energy Technology Data Exchange (ETDEWEB)

    Varlam, C.; Stefanescu, I.; Popescu, I.; Faurescu, I. [National Inst. for Cryogenic and Isotopic Technologies, PO Box 10, Rm. Valcea, 24050 (Romania)

    2008-07-15

    Establishing the tritium level along the Romanian Black Sea Coast, after 10 years of exploitation of the nuclear power plant from Cernavoda, is a first step in evaluating its impact on the Black Sea ecosystem. The monitoring program consists of tritium activity concentration measurement in sea water and precipitation from Black Sea Coast between April 2005 and April 2006. The sampling points were spread over the Danube-Black Sea Canal - before the locks Agigea and Navodari, and Black Sea along the coast to the Bulgarian border. The average tritium concentration in sea water collected from the sampling locations had the value of 11.1 {+-} 2.1 TU, close to tritium concentration in precipitation. Although an operating nuclear power plant exists in the monitored area, the values of tritium concentration in two locations are slightly higher than those recorded elsewhere. To conclude, it could be emphasized that until now, Cernavoda NPP did not had any influence on the tritium concentration of the Black Sea Shore. (authors)

  11. Development of the Bulgarian Sea Level Service

    Science.gov (United States)

    Palazov, Atanas

    2013-04-01

    Systematic sea level measurements have been started in Bulgaria in the beginning of 20th century and nowadays there are 16 coastal sea level stations in operation. Operators of sea level stations are: National Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences (NIMH) - 6 stations, Cadastre Agency, Ministry of Regional Development and Public Works (CA) - 4 stations, Port Infrastructure (PI) - 5 stations and Institute of Oceanology, Bulgarian Academy of Sciences (IO-BAS) - 1 station. Six of them are able to provide real time data. The sea level observations in the network of NIMH, performed at six main Bulgarian ports using standard poles, started in 1910. The program, implemented on the NIMH stations, includes daily measurements of the sea level with water gauges (poles). The position of a zero mark of the water gauge is checked once per year. The sea level network of the CA consists of 4 stations: Varna and Burgas (operational since 1928), Irakly and Ahtopol (since 1971). These stations are equipped with stilling-well tide gauges and with mechanical writing devices which draws sea level changes on paper. A mechanical paper writing instruments were installed in Varna and Burgas during 1928 and in 1971, a new paper writing instruments of type SUM (Russian) were installed in the stations of Irakly and Ahtopol. A set of five sea level stations in the ports of Balchik, Varna west, Pomorie, Burgas and Oil port Burgas was build during 2009 in the frame of Port Operational Marine Observing System (POMOS), equipped with high accuracy microwave instruments and operated by PI. In 2010 a new sea level station was set up in the IO-BAS coastal research base Shkorpolovtci. The station is equipped with high accuracy microwave instrument. These six stations are providing real time data. According to the decision of the Council of Ministers in 2012 sea level stations in Varna, Irakly, Burgas and Ahtopol will be operated jointly by Bulgarian Academy of Sciences and

  12. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 2.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  13. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  14. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.5 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  15. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.0 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  16. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.5 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  17. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.0 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  18. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  19. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.5 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  20. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 2.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  1. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 2.0 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  2. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.5 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  3. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.5 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  4. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  5. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.0 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  6. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.5 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  7. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.5 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  8. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.0 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  9. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.5 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  10. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 2.0 m: ocean currents projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived ocean current velocities (in meters per second) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The...

  11. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal...

  12. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 2.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal...

  13. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 1.5 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal...

  14. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.5 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal...

  15. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal Storm...

  16. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 Phase 1 (100-year storm) sea-level rise 0.0 m: wave-hazard projections

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Projected Hazard: Model-derived significant wave height (in meters) for the given storm condition and sea-level rise (SLR) scenario. Model Summary: The Coastal...

  17. BRICK v0.2, a simple, accessible, and transparent model framework for climate and regional sea-level projections

    Directory of Open Access Journals (Sweden)

    T. E. Wong

    2017-07-01

    Full Text Available Simple models can play pivotal roles in the quantification and framing of uncertainties surrounding climate change and sea-level rise. They are computationally efficient, transparent, and easy to reproduce. These qualities also make simple models useful for the characterization of risk. Simple model codes are increasingly distributed as open source, as well as actively shared and guided. Alas, computer codes used in the geosciences can often be hard to access, run, modify (e.g., with regards to assumptions and model components, and review. Here, we describe the simple model framework BRICK (Building blocks for Relevant Ice and Climate Knowledge v0.2 and its underlying design principles. The paper adds detail to an earlier published model setup and discusses the inclusion of a land water storage component. The framework largely builds on existing models and allows for projections of global mean temperature as well as regional sea levels and coastal flood risk. BRICK is written in R and Fortran. BRICK gives special attention to the model values of transparency, accessibility, and flexibility in order to mitigate the above-mentioned issues while maintaining a high degree of computational efficiency. We demonstrate the flexibility of this framework through simple model intercomparison experiments. Furthermore, we demonstrate that BRICK is suitable for risk assessment applications by using a didactic example in local flood risk management.

  18. Spatial-temporal analysis of sea level changes in China seas and neighboring oceans by merged altimeter data

    Science.gov (United States)

    Xu, Yao; Zhou, Bin; Yu, Zhifeng; Lei, Hui; Sun, Jiamin; Zhu, Xingrui; Liu, Congjin

    2017-01-01

    The knowledge of sea level changes is critical important for social, economic and scientific development in coastal areas. Satellite altimeter makes it possible to observe long term and large scale dynamic changes in the ocean, contiguous shelf seas and coastal zone. In this paper, 1993-2015 altimeter data of Topex/Poseidon and its follow-on missions is used to get a time serious of continuous and homogeneous sea level anomaly gridding product. The sea level rising rate is 0.39 cm/yr in China Seas and the neighboring oceans, 0.37 cm/yr in the Bo and Yellow Sea, 0.29 cm/yr in the East China Sea and 0.40 cm/yr in the South China Sea. The mean sea level and its rising rate are spatial-temporal non-homogeneous. The mean sea level shows opposite characteristics in coastal seas versus open oceans. The Bo and Yellow Sea has the most significant seasonal variability. The results are consistent with in situ data observation by the Nation Ocean Agency of China. The coefficient of variability model is introduced to describe the spatial-temporal variability. Results show that the variability in coastal seas is stronger than that in open oceans, especially the seas off the entrance area of the river, indicating that the validation of altimeter data is less reasonable in these seas.

  19. Greenland ice sheet contribution to sea level rise during the last interglacial period: a modelling study driven and constrained by ice core data

    Directory of Open Access Journals (Sweden)

    A. Quiquet

    2013-02-01

    Full Text Available As pointed out by the forth assessment report of the Intergovernmental Panel on Climate Change, IPCC-AR4 (Meehl et al., 2007, the contribution of the two major ice sheets, Antarctica and Greenland, to global sea level rise, is a subject of key importance for the scientific community. By the end of the next century, a 3–5 °C warming is expected in Greenland. Similar temperatures in this region were reached during the last interglacial (LIG period, 130–115 ka BP, due to a change in orbital configuration rather than to an anthropogenic forcing. Ice core evidence suggests that the Greenland ice sheet (GIS survived this warm period, but great uncertainties remain about the total Greenland ice reduction during the LIG. Here we perform long-term simulations of the GIS using an improved ice sheet model. Both the methodologies chosen to reconstruct palaeoclimate and to calibrate the model are strongly based on proxy data. We suggest a relatively low contribution to LIG sea level rise from Greenland melting, ranging from 0.7 to 1.5 m of sea level equivalent, contrasting with previous studies. Our results suggest an important contribution of the Antarctic ice sheet to the LIG highstand.

  20. Solution notches, earthquakes, and sea level, Haiti

    Science.gov (United States)

    Schiffman, C. R.; Mildor, B. S.; Bilham, R. G.

    2010-12-01

    Shortly after the 12 January 2010 Haiti earthquake, we installed an array of five tide gauges to determine sea level and its variability in the region of uplifted corals on the coast SW of Leogane, Haiti, that had been uplift ≤30 cm during the earthquake. Each gauge consists of a pressure transducer bolted 50-80 cm below mean sea level, which samples the difference between atmospheric pressure and sea pressure every 10 minutes. The data are transmitted via the Iridium satellite and are publically available with a latency of 10 minutes to 2 hours. The measurements reveal a maximum tidal range of ≈50 cm with 2-4 week oscillations in mean sea level of several cm. Sea slope, revealed by differences between adjacent gauges, varies 2-5 cm per 10 km at periods of 2-5 weeks, which imposes a disappointing limit to the utility of the gauges in estimating post seismic vertical motions. A parallel study of the form and elevation of coastal notches and mushroom rocks (rocks notched on all sides, hence forming a mushroom shape), along the coast west of Petit Goave suggests that these notches may provide an uplift history of the region over the past several hundreds of years. Notch sections in two areas were contoured, digitized, and compared to mean sea level. The notches mimic the histogram of sea level, suggesting that they are formed by dissolution by acidic surface waters. Notches formed two distinct levels, one approximately 58 cm above mean sea level, and the other approximately 157 cm above mean sea level. Several landslide blocks fell into the sea during the 2010 earthquake, and we anticipate these are destined for conversion to future mushroom rocks. Surfaces have been prepared on these blocks to study the rate of notch formation in situ, and samples are being subjected to acid corrosion in laboratory conditions, with the hope that the depth of notches may provide an estimate of the time of fall of previous rocks to help constrain the earthquake history of this area

  1. Flooding Model as the Analysis of the Sea Level Increase as a Result of Global Warming in Coastal Area in Lampung

    Directory of Open Access Journals (Sweden)

    Agung Kurniawan

    2017-08-01

    Full Text Available The melting of ice layers, as a direct impact on global warming, is indicated from a lesser thickness of ice layers is specifically causing an increase on the sea level. Lampung, as a province that has an ecosistem of regional coast, can be estimated to submerge. Flood modelling can be done to know the estimated flood range. The model of the flooded region is taken from Shuttle Radar Topography Mission(SRTM data, which is nomalized to get the visualisation of Digital Elevation Model (DEM. The purpose of this research is to know the estimated region of provincial coast of Lampung that is going to be flooded because of the raising of sea surface. This research uses flood inundation technique that uses one of the GIS mapping software. The result can be used as consideration to achieve policy in the building of regional coast. The regions that are flooded based on the scenario of the raising of two and three meter surface sea level are East Lampung Regency, West Lampung Regency, South Lampung Regency, Tanggamus Regency, Pesawaran Regency, and Bandar Lampung.

  2. Increasing mean sea level and decreasing storminess: a multi-model and multi-scenario estimate of contrasting factors that will affect the Mediterranean coastline in the 21st century

    Science.gov (United States)

    D'Agostino, R.; Lionello, P.; Conte, D.; Marzo, L.; Scarascia, L.

    2016-12-01

    This study estimates the factors (storm surges, ocean wind generated waves, sea level rise) responsible for the maximum level that water reaches during a storm along the coast of the Mediterranean Sea. The results of regional climate models are used for driving wave and storm surge models and for estimating thermosteric and halosteric effects on sea level. Seamless wave and sea level simulations covering the period 1950-2100 have been carried out for the whole Mediterranean Sea with forcings that have been produced by different regional climate models under multiple emission scenarios (A1B, RCP4.5, RCP8.5). This large set of results allow to describe the likely future changes of regional marine storminess and their uncertainty depending on emission scenario, climate model and inter-decadal variability. In the Mediterranean Sea, steric expansion and storminess are shown to be contrasting factors: during the 21st century, wave and storm surge maxima will decrease, while thermosteric expansion will increase mean sea level. These two effects will to a large extent compensate each other, so that mass addition from the global ocean that will enter through the Gibraltar Strait in the Mediterranean Sea will likely become the dominant factor and determine an increase of the maximum water level along most of the coastline. The superposition of hazard level changes and morphology of the coast allows to identify parts of the Mediterranean coastline that are potentially at risk in the future.

  3. Long-term Caspian Sea level change

    Science.gov (United States)

    Chen, J. L.; Pekker, T.; Wilson, C. R.; Tapley, B. D.; Kostianoy, A. G.; Cretaux, J.-F.; Safarov, E. S.

    2017-07-01

    Caspian Sea level (CSL) has undergone substantial fluctuations during the past several hundred years. The causes over the entire historical period are uncertain, but we investigate here large changes seen in the past several decades. We use climate model-predicted precipitation (P), evaporation (E), and observed river runoff (R) to reconstruct long-term CSL changes for 1979-2015 and show that PER (P-E + R) flux predictions agree very well with observed CSL changes. The observed rapid CSL increase (about 12.74 cm/yr) and significant drop ( -6.72 cm/yr) during the periods 1979-1995 and 1996-2015 are well accounted for by integrated PER flux predictions of +12.38 and -6.79 cm/yr, respectively. We show that increased evaporation rates over the Caspian Sea play a dominant role in reversing the increasing trend in CSL during the past 37 years. The current long-term decline in CSL is expected to continue into the foreseeable future, under global warming scenarios.

  4. The importance of sea-level research (Plinius Medal Lecture)

    Science.gov (United States)

    Horton, Benjamin

    2016-04-01

    200 million people worldwide live in coastal regions less than 5 meters above sea level. By the end of the 21st century, this figure is estimated to increase to 500 million. These low-lying coastal regions are vulnerable to changes in sea level brought about by climate change, storms or earthquakes. But the historic and instrumental record is too short to fully understand the climate relationships and capture the occurrence of the rare, but most destructive events. The coastal sedimentary record provides a long-term and robust paleo perspective on the rates, magnitudes and spatial variability of sea-level rise and the frequency (recurrence interval) and magnitude of destructive events. Reconstructions of paleo sea level are important for identifying the meltwater contributions, constraining parameters in Earth-Ice models, and estimating past and present rates of spatially variable sea-level change associated glacial isostatic adjustment, sediment compaction and tidal range variability. Sea-level reconstructions capture multiple phases of climate and sea-level behavior for model calibration and provide a pre-anthropogenic background against which to compare recent trends. Pre-historic earthquakes (Mw>8.0) are often associated with abrupt and cyclical patterns of vertical land-motion that are manifest in coastal sedimentary archives as abrupt changes in relative sea level. Geologic evidence of paleoearthquakes elucidates characteristic and repeated pattern of land-level movements associated with the earthquake-deformation cycle. Tsunamis and storms leave behind anomalous and characteristic sediment that is incorporated into the coastal sedimentary record often as evidence of a high-energy event affecting a low-energy, depositional environment. Records of tsunamis developed from the sedimentary deposits they leave behind improve understanding of tsunami processes and frequency by expanding the age range of events available for study. Reconstructions of paleo storms

  5. Overestimation of marsh vulnerability to sea level rise

    Science.gov (United States)

    Kirwan, Matthew L.; Temmerman, Stijn; Skeehan, Emily E.; Guntenspergen, Glenn R.; Fagherazzi, Sergio

    2016-01-01

    Coastal marshes are considered to be among the most valuable and vulnerable ecosystems on Earth, where the imminent loss of ecosystem services is a feared consequence of sea level rise. However, we show with a meta-analysis that global measurements of marsh elevation change indicate that marshes are generally building at rates similar to or exceeding historical sea level rise, and that process-based models predict survival under a wide range of future sea level scenarios. We argue that marsh vulnerability tends to be overstated because assessment methods often fail to consider biophysical feedback processes known to accelerate soil building with sea level rise, and the potential for marshes to migrate inland.

  6. 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.

  7. 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...

  8. Sea ice biogeochemistry: a guide for modellers.

    Directory of Open Access Journals (Sweden)

    Letizia Tedesco

    Full Text Available Sea ice is a fundamental component of the climate system and plays a key role in polar trophic food webs. Nonetheless sea ice biogeochemical dynamics at large temporal and spatial scales are still rarely described. Numerical models may potentially contribute integrating among sparse observations, but available models of sea ice biogeochemistry are still scarce, whether their relevance for properly describing the current and future state of the polar oceans has been recently addressed. A general methodology to develop a sea ice biogeochemical model is presented, deriving it from an existing validated model application by extension of generic pelagic biogeochemistry model parameterizations. The described methodology is flexible and considers different levels of ecosystem complexity and vertical representation, while adopting a strategy of coupling that ensures mass conservation. We show how to apply this methodology step by step by building an intermediate complexity model from a published realistic application and applying it to analyze theoretically a typical season of first-year sea ice in the Arctic, the one currently needing the most urgent understanding. The aim is to (1 introduce sea ice biogeochemistry and address its relevance to ocean modelers of polar regions, supporting them in adding a new sea ice component to their modelling framework for a more adequate representation of the sea ice-covered ocean ecosystem as a whole, and (2 extend our knowledge on the relevant controlling factors of sea ice algal production, showing that beyond the light and nutrient availability, the duration of the sea ice season may play a key-role shaping the algal production during the on going and upcoming projected changes.

  9. Sea Ice Biogeochemistry: A Guide for Modellers

    Science.gov (United States)

    Tedesco, Letizia; Vichi, Marcello

    2014-01-01

    Sea ice is a fundamental component of the climate system and plays a key role in polar trophic food webs. Nonetheless sea ice biogeochemical dynamics at large temporal and spatial scales are still rarely described. Numerical models may potentially contribute integrating among sparse observations, but available models of sea ice biogeochemistry are still scarce, whether their relevance for properly describing the current and future state of the polar oceans has been recently addressed. A general methodology to develop a sea ice biogeochemical model is presented, deriving it from an existing validated model application by extension of generic pelagic biogeochemistry model parameterizations. The described methodology is flexible and considers different levels of ecosystem complexity and vertical representation, while adopting a strategy of coupling that ensures mass conservation. We show how to apply this methodology step by step by building an intermediate complexity model from a published realistic application and applying it to analyze theoretically a typical season of first-year sea ice in the Arctic, the one currently needing the most urgent understanding. The aim is to (1) introduce sea ice biogeochemistry and address its relevance to ocean modelers of polar regions, supporting them in adding a new sea ice component to their modelling framework for a more adequate representation of the sea ice-covered ocean ecosystem as a whole, and (2) extend our knowledge on the relevant controlling factors of sea ice algal production, showing that beyond the light and nutrient availability, the duration of the sea ice season may play a key-role shaping the algal production during the on going and upcoming projected changes. PMID:24586604

  10. Sea ice biogeochemistry: a guide for modellers.

    Science.gov (United States)

    Tedesco, Letizia; Vichi, Marcello

    2014-01-01

    Sea ice is a fundamental component of the climate system and plays a key role in polar trophic food webs. Nonetheless sea ice biogeochemical dynamics at large temporal and spatial scales are still rarely described. Numerical models may potentially contribute integrating among sparse observations, but available models of sea ice biogeochemistry are still scarce, whether their relevance for properly describing the current and future state of the polar oceans has been recently addressed. A general methodology to develop a sea ice biogeochemical model is presented, deriving it from an existing validated model application by extension of generic pelagic biogeochemistry model parameterizations. The described methodology is flexible and considers different levels of ecosystem complexity and vertical representation, while adopting a strategy of coupling that ensures mass conservation. We show how to apply this methodology step by step by building an intermediate complexity model from a published realistic application and applying it to analyze theoretically a typical season of first-year sea ice in the Arctic, the one currently needing the most urgent understanding. The aim is to (1) introduce sea ice biogeochemistry and address its relevance to ocean modelers of polar regions, supporting them in adding a new sea ice component to their modelling framework for a more adequate representation of the sea ice-covered ocean ecosystem as a whole, and (2) extend our knowledge on the relevant controlling factors of sea ice algal production, showing that beyond the light and nutrient availability, the duration of the sea ice season may play a key-role shaping the algal production during the on going and upcoming projected changes.

  11. Sea level change. Inherited landscapes and sea level change.

    Science.gov (United States)

    Cloetingh, Sierd; Haq, Bilal U

    2015-01-23

    Enabled by recently gained understanding of deep-seated and surficial Earth processes, a convergence of views between geophysics and sedimentary geology has been quietly taking place over the past several decades. Surface topography resulting from lithospheric memory, retained at various temporal and spatial scales, has become the connective link between these two methodologically diverse geoscience disciplines. Ideas leading to the hypothesis of plate tectonics originated largely with an oceanic focus, where dynamic and mostly horizontal movements of the crust could be envisioned. But when these notions were applied to the landscapes of the supposedly rigid plate interiors, there was less success in explaining the observed anomalies in terrestrial topography. Solid-Earth geophysics has now reached a developmental stage where vertical movements can be measured and modeled at meaningful scales and the deep-seated structures can be imaged with increasing resolution. Concurrently, there have been advances in quantifying mechanical properties of the lithosphere (the solid outer skin of Earth, usually defined to include both the crust and the solid but elastic upper mantle above the asthenosphere). The lithosphere acts as the intermediary that transfers the effects of mantle dynamics to the surface. These developments have allowed us to better understand the previously puzzling topographic features of plate interiors and continental margins. On the sedimentary geology side, new quantitative modeling techniques and holistic approaches to integrating source-to-sink sedimentary systems have led to clearer understanding of basin evolution and sediment budgets that allow the reconstruction of missing sedimentary records and past geological landscapes.

  12. 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.

  13. The record of Pliocene sea-level change at Enewetak Atoll

    Science.gov (United States)

    Wardlaw, Bruce R.; Quinn, Terrence M.

    Detailed seismic stratigraphy, lithostratigraphy, and chemostratigraphy indicate that atoll-wide subaerial exposure surfaces (major disconformities) developed during major sea-level lowstands form prominent seismic reflectors and are coincident with biostratigraphic breaks in the Plio-Pleistocene on Enewetak Atoll. Sea-level models based on the stratigraphic position and age of major disconformities suggest a maximum sea-level highstand elevation of 36 m above present sea level and a maximum sea-level lowstand elevation of 63 m below present sea level for the Pliocene.

  14. Calibrating a glaciological model of the Greenland ice sheet from the Last Glacial Maximum to present-day using field observations of relative sea level and ice extent

    Science.gov (United States)

    Simpson, Matthew J. R.; Milne, Glenn A.; Huybrechts, Philippe; Long, Antony J.

    2009-08-01

    We constrain a three-dimensional thermomechanical model of Greenland ice sheet (GrIS) evolution from the Last Glacial Maximum (LGM, 21 ka BP) to the present-day using, primarily, observations of relative sea level (RSL) as well as field data on past ice extent. Our new model (Huy2) fits a majority of the observations and is characterised by a number of key features: (i) the ice sheet had an excess volume (relative to present) of 4.1 m ice-equivalent sea level at the LGM, which increased to reach a maximum value of 4.6 m at 16.5 ka BP; (ii) retreat from the continental shelf was not continuous around the entire margin, as there was a Younger Dryas readvance in some areas. The final episode of marine retreat was rapid and relatively late (c. 12 ka BP), leaving the ice sheet land based by 10 ka BP; (iii) in response to the Holocene Thermal Maximum (HTM) the ice margin retreated behind its present-day position by up to 80 km in the southwest, 20 km in the south and 80 km in a small area of the northeast. As a result of this retreat the modelled ice sheet reaches a minimum extent between 5 and 4 ka BP, which corresponds to a deficit volume (relative to present) of 0.17 m ice-equivalent sea level. Our results suggest that remaining discrepancies between the model and the observations are likely associated with non-Greenland ice load, differences between modelled and observed present-day ice elevation around the margin, lateral variations in Earth structure and/or the pattern of ice margin retreat.

  15. Visualizing Sea Level Rise with Augmented Reality

    Science.gov (United States)

    Kintisch, E. S.

    2013-12-01

    Looking Glass is an application on the iPhone that visualizes in 3-D future scenarios of sea level rise, overlaid on live camera imagery in situ. Using a technology known as augmented reality, the app allows a layperson user to explore various scenarios of sea level rise using a visual interface. Then the user can see, in an immersive, dynamic way, how those scenarios would affect a real place. The first part of the experience activates users' cognitive, quantitative thinking process, teaching them how global sea level rise, tides and storm surge contribute to flooding; the second allows an emotional response to a striking visual depiction of possible future catastrophe. This project represents a partnership between a science journalist, MIT, and the Rhode Island School of Design, and the talk will touch on lessons this projects provides on structuring and executing such multidisciplinary efforts on future design projects.

  16. Incision of alluvial channels in response to a continuous base level fall: Field characterization, modeling, and validation along the Dead Sea

    Science.gov (United States)

    Ben Moshe, L.; Haviv, I.; Enzel, Y.; Zilberman, E.; Matmon, A.

    2008-01-01

    The dramatic lake level drop of the Dead Sea during the twentieth century (˜ 30 m) provides a field-scale experiment in transport-limited incision of gravel-bed channels in response to quasi-continuous base level fall at approximately constant rate. We apply a one-dimensional numerical incision model based on a linear diffusion equation to seven ephemeral channels draining into the Dead Sea. The model inputs include the measured twentieth century lake level curve, annual shoreline location (i.e., annual channel lengthening following the lake level drop), reconstructed longitudinal profiles of each of the channels based on mapped and surveyed terraces, and the current profiles of the active channels. The model parameters included the diffusion coefficient and the upstream-derived sediment flux. Both were first calibrated using a set of longitudinal profiles of known ages and then validated using additional sets of longitudinal profiles. The maximum at-station total incision observed at each of the studied channels was significantly less then the total lake level drop and varied in response to both drainage area and lake bathymetry. The model applied predicted degradation rates and the pattern of degradation with high accuracy. This suggests that sediment flux in the modeled channels is indeed linearly dependent on slope. Further support for this linear dependency is provided by a linear correlation between the diffusion coefficient and the mean annual rain volume over each basin (a proxy for discharge). The model presented could be a valuable tool for planning in rapid base level fall environments where incision may risk infrastructure.

  17. The Sea Level Fingerprints of Global Change

    Science.gov (United States)

    Mitrovica, J. X.; Hay, C.; Kopp, R. E., III; Morrow, E.

    2014-12-01

    It may be difficult to persuade those living in northern Europe that the sea level changes that their coastal communities face depends less on the total melting of polar ice sheets and glaciers than on the individual contributions to this total. In particular, melting of a specific ice sheet or mountain glacier drives deformational, gravitational and rotational perturbations to the Earth system that are manifest in a unique geometry, or fingerprint, of global sea level change. For example, melting from the Greenland Ice Sheet equivalent to 1 mm/yr of global mean sea level (GMSL) rise will lead to sea level rise of ~0 mm/yr in Dublin, ~0.2 mm/yr in Amsterdam, ~0.4 mm/yr in Boston and ~1.2 mm/yr in Cape Town. In contrast, if the same volume of ice melted from the West Antarctic Ice Sheet, all of the above sites would experience a sea level rise in the range 1.1-1.2 mm/yr. These fingerprints of modern ice melting, together with ocean thermal expansion and dynamic effects, and the ongoing signal from glacial isostatic adjustment in response to the last ice age, combine to produce a sea level field with significant geographic variability. In this talk I will highlight an analysis of global tide gauge records that takes full advantage of this variability to estimate both GMSL and the sources of meltwater over the last century, and to project GMSL to the end of the current century.

  18. Terrestrial Waters and Sea Level Variations on Interannual Time Scale

    Science.gov (United States)

    Llovel, W.; Becker, M.; Cazenave, A.; Jevrejeva, S.; Alkama, R.; Decharme, B.; Douville, H.; Ablain, M.; Beckley, B.

    2011-01-01

    On decadal to multi-decadal time scales, thermal expansion of sea waters and land ice loss are the main contributors to sea level variations. However, modification of the terrestrial water cycle due to climate variability and direct anthropogenic forcing may also affect sea level. For the past decades, variations in land water storage and corresponding effects on sea level cannot be directly estimated from observations because these are almost non-existent at global continental scale. However, global hydrological models developed for atmospheric and climatic studies can be used for estimating total water storage. For the recent years (since mid-2002), terrestrial water storage change can be directly estimated from observations of the GRACE space gravimetry mission. In this study, we analyse the interannual variability of total land water storage, and investigate its contribution to mean sea level variability at interannual time scale. We consider three different periods that, each, depend on data availability: (1) GRACE era (2003-2009), (2) 1993-2003 and (3) 1955-1995. For the GRACE era (period 1), change in land water storage is estimated using different GRACE products over the 33 largest river basins worldwide. For periods 2 and 3, we use outputs from the ISBA-TRIP (Interactions between Soil, Biosphere, and Atmosphere-Total Runoff Integrating Pathways) global hydrological model. For each time span, we compare change in land water storage (expressed in sea level equivalent) to observed mean sea level, either from satellite altimetry (periods 1 and 2) or tide gauge records (period 3). For each data set and each time span, a trend has been removed as we focus on the interannual variability. We show that whatever the period considered, interannual variability of the mean sea level is essentially explained by interannual fluctuations in land water storage, with the largest contributions arising from tropical river basins.

  19. Uncertainty quantification of Antarctic contribution to sea-level rise using the fast Elementary Thermomechanical Ice Sheet (f.ETISh) model

    Science.gov (United States)

    Bulthuis, Kevin; Arnst, Maarten; Pattyn, Frank; Favier, Lionel

    2017-04-01

    Uncertainties in sea-level rise projections are mostly due to uncertainties in Antarctic ice-sheet predictions (IPCC AR5 report, 2013), because key parameters related to the current state of the Antarctic ice sheet (e.g. sub-ice-shelf melting) and future climate forcing are poorly constrained. Here, we propose to improve the predictions of Antarctic ice-sheet behaviour using new uncertainty quantification methods. As opposed to ensemble modelling (Bindschadler et al., 2013) which provides a rather limited view on input and output dispersion, new stochastic methods (Le Maître and Knio, 2010) can provide deeper insight into the impact of uncertainties on complex system behaviour. Such stochastic methods usually begin with deducing a probabilistic description of input parameter uncertainties from the available data. Then, the impact of these input parameter uncertainties on output quantities is assessed by estimating the probability distribution of the outputs by means of uncertainty propagation methods such as Monte Carlo methods or stochastic expansion methods. The use of such uncertainty propagation methods in glaciology may be computationally costly because of the high computational complexity of ice-sheet models. This challenge emphasises the importance of developing reliable and computationally efficient ice-sheet models such as the f.ETISh ice-sheet model (Pattyn, 2015), a new fast thermomechanical coupled ice sheet/ice shelf model capable of handling complex and critical processes such as the marine ice-sheet instability mechanism. Here, we apply these methods to investigate the role of uncertainties in sub-ice-shelf melting, calving rates and climate projections in assessing Antarctic contribution to sea-level rise for the next centuries using the f.ETISh model. We detail the methods and show results that provide nominal values and uncertainty bounds for future sea-level rise as a reflection of the impact of the input parameter uncertainties under

  20. Regional sea level change in the Thailand-Indonesia region

    Science.gov (United States)

    Fenoglio-Marc, L.; Becker, M. H.; Buchhaupt, C.

    2013-12-01

    It is expected that the regional sea level rise will strongly affect particular regions with direct impacts including submergence of coastal zones, rising water tables and salt intrusion into groundwaters. It can possibly also exacerbate other factors as floodings, associated to storms and hurricanes, as well as ground subsidence of anthropogenic nature. The Thailand-Vietnam-Indonesian region is one of those zones. On land, the Chao-Praya and Mekong Delta are fertile alluvial zones. The potential for sea level increases and extreme floodings due to global warming makes the Deltas a place where local, regional, and global environmental changes are converging. We investigate the relative roles of regional and global mechanisms resulting in multidecadal variations and inflections in the rate of sea level change. Altimetry and GRACE data are used to investigate the variation of land floodings. The land surface water extent is evaluated at 25 km sampling intervals over fifteen years (1993-2007) using a multisatellite methodology which captures the extent of episodic and seasonal inundations, wetlands, rivers, lakes, and irrigated agriculture, using passive and active (microwaves and visible observations. The regional sea level change is analysed during the period 1993-2012 using satellite altimetry, wind and ocean model data, tide gauge data and GPS. The rates of absolute eustatic sea level rise derived from satellite altimetry through 19-year long precise altimeter observations are in average higher than the global mean rate. Several tide gauge records indicate an even higher sea level rise relative to land. We show that the sea level change is closely linked to the ENSO mode of variability and strongly affected by changes in wind forcing and ocean circulation. We have determined the vertical crustal motion at a given tide gauge location by differencing the tide gauge sea level time-series with an equivalent time-series derived from satellite altimetry and by computing

  1. Methane Gas Hydrate Stability Models on Continental Shelves in Response to Glacio-Eustatic Sea Level Variations: Examples from Canadian Oceanic Margins

    Directory of Open Access Journals (Sweden)

    Jan Safanda

    2013-11-01

    Full Text Available We model numerically regions of the Canadian continental shelves during successive glacio-eustatic cycles to illustrate past, current and future marine gas hydrate (GH stability and instability. These models indicated that the marine GH resource has dynamic features and the formation age and resource volumes depend on the dynamics of the ocean-atmosphere system as it responds to both natural (glacial-interglacial and anthropogenic (climate change forcing. Our models focus on the interval beginning three million years ago (i.e., Late Pliocene-Holocene. They continue through the current interglacial and they are projected to its anticipated natural end. During the current interglacial the gas hydrate stability zone (GHSZ thickness in each region responded uniquely as a function of changes in water depth and sea bottom temperature influenced by ocean currents. In general, the GHSZ in the deeper parts of the Pacific and Atlantic margins (≥1316 m thinned primarily due to increased water bottom temperatures. The GHSZ is highly variable in the shallower settings on the same margins (~400–500 m. On the Pacific Margin shallow GH dissociated completely prior to nine thousand years ago but the effects of subsequent sea level rise reestablished a persistent, thin GHSZ. On the Atlantic Margin Scotian Shelf the warm Gulf Stream caused GHSZ to disappear completely, whereas in shallow water depths offshore Labrador the combination of the cool Labrador Current and sea level rise increased the GHSZ. If future ocean bottom temperatures remain constant, these general characteristics will persist until the current interglacial ends. If the sea bottom warms, possibly in response to global climate change, there could be a significant reduction to complete loss of GH stability, especially on the shallow parts of the continental shelf. The interglacial GH thinning rates constrain rates at which carbon can be transferred between the GH reservoir and the atmosphere

  2. Investigation of the LIG sea-level highstand with massive ensembles

    Science.gov (United States)

    Düsterhus, André; Tamisiea, Mark E.; Hibbert, Fiona D.; Rohling, Eelco J.

    2017-04-01

    Paleoclimatic sea-level analysis is based upon the evaluation of sparse indirect observational data, the sea-level indicators, and models for sea-level fluctuations, with a wide range of complexity. Individual records of paleo sea level depend not only upon the change in global ice volume, but also on the crustal deformation and gravity changes that are significant both near the glaciers and around the world. Understanding of these processes for the past is essential for interpreting the observations and generating better estimates of future changes. We use massive ensemble approaches to analyse sea-level changes during the last interglacial (LIG). Employing a Bayesian statistical analysis, we compare the sea-level indicators to model-generated sea-level estimates. As a result we gain insight into the development of the ice sheets, the influence of the Earth deformation and the evolution of higher-than-present-day sea level during that period. This contribution gives an overview of our sea-level analysis during the LIG. We focus on the highstand of sea level during the LIG and the duration of higher than modern sea level. The analysis helps to answer questions of the effect of the uncertainties in the indicators, both in height as well as in time, on features of the estimated global-average sea level. In particular, we address how well the data resolve sea-level oscillations during the LIG.

  3. Sea level Variability and Juan de Fuca Bathymetry

    Science.gov (United States)

    Huybers, P. J.; Boulahanis, B.; Proistosescu, C.; Langmuir, C. H.; Carbotte, S. M.; Katz, R. F.

    2015-12-01

    That deglaciation influences mid-ocean ridge volcanism is well established for Iceland, where depressurization associated with melting a ~2 km ice cap led to order of magnitude increases in volcanism during the last deglaciation. The case was also made that the more subtle ~100 m changes in sea level that accompany glacial cycles have identifiable implications for undersea mid-ocean ridge systems using both models and data from the Australian-Antarctic Ridge (Crowley et al., 2015). Sea level rising at ~1 cm/year during deglaciation leads to an expectation of ~10% decreases in melt production at ridges, given mantle upwelling rates of ˜3 cm/yr at intermediate spreading ridges and mantle density being ~3 times that of seawater. The implications of variations in melt production for bathymetry, however, involve numerous considerations, including whether melt signals are cancelled within the melt column, appreciably alter accretionary or fault processes, and have identifiable surface expressions. Further empirical assessment of bathymetry is thus useful for purposes of confirming patterns and constraining processes. Here we report on spectral analyses of bathymetry recently acquired from the Juan de Fuca ridge between 44°30'N and 45°15'N during the SeaVOICE expedition. Multibeam swath sonar data were acquired with an EM122 sonar insonfiying seafloor to crustal ages of ˜2 ma with 35 m spatial resolution. We examine (1.) the statistical significance of concentrations of bathymetric variability at the 100 ky, 41 ky, and 23 ky periods characteristic of late-Pleistocene sea level variability; (2.) whether sea level responses are primarily at 41 ky periods in crust accreted during the early Pleistocene, when global sea level variations were primarily at this period; and (3.) if sea level responses are superimposed on bathymetry variations or, instead, align with fault features. We also note that Juan de Fuca's proximity to the Cordilleran Ice Sheet implies that regional

  4. Decadal and long-term sea level variability in the tropical Indo-Pacific Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Nidheesh, A.G.; Lengaigne, M.; Vialard, J.; Unnikrishnan, A.S.; Dayan, H.

    Decadal and long-term steric sea level variations over 1966-2007 period in the Indo-Pacific sector were analysed using an ocean general circulation model forced by reanalysis winds. The simulated steric sea level compares favourably with sea level...

  5. Global Sea Surface Temperature and Sea Level Rise Estimation with Optimal Historical Time Lag Data

    Directory of Open Access Journals (Sweden)

    Mustafa M. Aral

    2016-11-01

    Full Text Available Prediction of global temperatures and sea level rise (SLR is important for sustainable development planning of coastal regions of the world and the health and safety of communities living in these regions. In this study, climate change effects on sea level rise is investigated using a dynamic system model (DSM with time lag on historical input data. A time-invariant (TI-DSM and time-variant dynamic system model (TV-DSM with time lag is developed to predict global temperatures and SLR in the 21st century. The proposed model is an extension of the DSM developed by the authors. The proposed model includes the effect of temperature and sea level states of several previous years on the current temperature and sea level over stationary and also moving scale time periods. The optimal time lag period used in the model is determined by minimizing a synthetic performance index comprised of the root mean square error and coefficient of determination which is a measure for the reliability of the predictions. Historical records of global temperature and sea level from 1880 to 2001 are used to calibrate the model. The optimal time lag is determined to be eight years, based on the performance measures. The calibrated model was then used to predict the global temperature and sea levels in the 21st century using a fixed time lag period and moving scale time lag periods. To evaluate the adverse effect of greenhouse gas emissions on SLR, the proposed model was also uncoupled to project the SLR based on global temperatures that are obtained from the Intergovernmental Panel on Climate Change (IPCC emission scenarios. The projected SLR estimates for the 21st century are presented comparatively with the predictions made in previous studies.

  6. A projection of future sea level

    NARCIS (Netherlands)

    Oerlemans, J.; Alfred-Wegener-lnstitut für Polar- und Meeresforschung, Bremerhaven, F.R.G.

    1989-01-01

    Evidence is reviewed that suggests faster sea-level rise when climate gets warmer. Four processes appear as dominating on a time scale of decades to centuries: melting of mountain glaciers and small ice caps, changes in the mass balance of the large polar ice sheets (Greenland, Antarctica), possible

  7. Impact of Altimeter Data Processing on Sea Level Studies

    Directory of Open Access Journals (Sweden)

    Clara Lázaro

    2006-03-01

    Full Text Available This study addresses the impact of satellite altimetry data processing on sea levelstudies at regional scale, with emphasis on the influence of various geophysical correctionsand satellite orbit on the structure of the derived interannual signal and sea level trend. Thework focuses on the analysis of TOPEX data for a period of over twelve years, for threeregions in the North Atlantic: Tropical (0o≤φ≤25o, Sub-Tropical (25o≤φ≤50o and Sub-Arctic (50o≤φ≤65o. For this analysis corrected sea level anomalies with respect to a meansea surface model have been derived from the GDR-Ms provided by AVISO by applyingvarious state-of-the-art models for the geophysical corrections. Results show that sea leveltrend determined from TOPEX altimetry is dependent on the adopted models for the majorgeophysical corrections. The main effects come from the sea state bias (SSB, and from theapplication or not of the inverse barometer (IB correction. After an appropriate modellingof the TOPEX A/B bias, the two analysed SSB models induce small variations in sea leveltrend, from 0.0 to 0.2 mm/yr, with a small latitude dependence. The difference in sea leveltrend determined by a non IB-corrected series and an IB-corrected one has a strong regionaldependence with large differences in the shape of the interannual signals and in the derivedlinear trends. The use of two different drift models for the TOPEX Microwave Radiometer(TMR has a small but non negligible effect on the North Atlantic sea level trend of about0.1 mm/yr. The interannual signals of sea level time series derived with the NASA and theCNES orbits respectively, show a small departure in the middle of the series, which has noimpact on the derived sea level trend. These results strike the need for a continuousimprovement in the modelling of the various effects that influence the altimetermeasurement.

  8. Holocene sea level, a semi-empirical contemplation

    Science.gov (United States)

    Bittermann, Klaus; Kemp, Andrew; Vermeer, Martin; Rahmstorf, Stefan

    2017-04-01

    Holocene eustatic sea level from approximately -10,000-1800 CE was characterized by an increase of about 60 m, 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 a semi-empirical sea-level model. 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., Pollard, D., & Tarasov, L. 2014. A data-constrained large ensemble analysis of Antarctic evolution since the Eemian. Quaternary science reviews

  9. A NOAA/NOS Sea Level Advisory

    Science.gov (United States)

    Sweet, W.

    2011-12-01

    In order for coastal communities to realize current impacts and become resilient to future changes, sea level advisories/bulletins are necessary that systematically monitor and document non-tidal anomalies (residuals) and flood-watch (elevation) conditions. The need became apparent after an exceptional sea level anomaly along the U.S. East Coast in June - July of 2009 when higher than normal sea levels coincided with a perigean-spring tide and flooded many coastal regions. The event spurred numerous public inquiries to the National Oceanic and Atmospheric Administration's (NOAA) Center for Operational Oceanographic Products and Services (CO-OPS) from coastal communities concerned because of the lack of any coastal storm signatures normally associated with such an anomaly. A subsequent NOAA report provided insight into some of the mechanisms involved in the event and methods for tracking their reoccurrences. NOAA/CO-OPS is the U.S. authority responsible for defining sea level datums and tracking their relative changes in support of marine navigation and national and state land-use boundaries. These efforts are supported by the National Water Level Observation Network (NWLON), whose long-term and widespread observations largely define a total water level measurement impacting a coastal community. NWLON time series provide estimates of local relative sea level trends, a product increasingly utilized by various stakeholders planning for the future. NWLON data also capture significant short-term changes and conveyance of high-water variations (from surge to seasonal scale) provides invaluable insight into inundation patterns ultimately needed for a more comprehensive planning guide. A NOAA/CO-OPS Sea Level Advisory Project will enhance high-water monitoring capabilities by: - Automatically detecting sea level anomalies and flood-watch occurrences - Seasonally calibrating the anomaly thresholds to a locality in terms of flood potential - Alerting for near

  10. 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.

  11. Dynamics of sea level rise and coastal flooding on a changing landscape

    National Research Council Canada - National Science Library

    Bilskie, M. V; Hagen, S. C; Medeiros, S. C; Passeri, D. L

    2014-01-01

    Standard approaches to determining the impacts of sea level rise (SLR) on storm surge flooding employ numerical models reflecting present conditions with modified sea states for a given SLR scenario...

  12. Cenozoic sea level and the rise of modern rimmed atolls

    Science.gov (United States)

    Toomey, Michael; Ashton, Andrew; Raymo, Maureen E.; Perron, J. Taylor

    2016-01-01

    Sea-level records from atolls, potentially spanning the Cenozoic, have been largely overlooked, in part because the processes that control atoll form (reef accretion, carbonate dissolution, sediment transport, vertical motion) are complex and, for many islands, unconstrained on million-year timescales. Here we combine existing observations of atoll morphology and corelog stratigraphy from Enewetak Atoll with a numerical model to (1) constrain the relative rates of subsidence, dissolution and sedimentation that have shaped modern Pacific atolls and (2) construct a record of sea level over the past 8.5 million years. Both the stratigraphy from Enewetak Atoll (constrained by a subsidence rate of ~ 20 m/Myr) and our numerical modeling results suggest that low sea levels (50–125 m below present), and presumably bi-polar glaciations, occurred throughout much of the late Miocene, preceding the warmer climate of the Pliocene, when sea level was higher than present. Carbonate dissolution through the subsequent sea-level fall that accompanied the onset of large glacial cycles in the late Pliocene, along with rapid highstand constructional reef growth, likely drove development of the rimmed atoll morphology we see today.

  13. Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations that 2C Global Warming Could Be Dangerous

    Science.gov (United States)

    Hansen, J.; Sato, Makiko; Hearty, Paul; Ruedy, Reto; Kelley, Maxwell; Masson-Delmotte, Valerie; Russell, Gary; Tselioudis, George; Cao, Junji; Rignot, Eric; Velicogna, Isabella; Tormey, Blair; Donovan, Bailey; Kandiano, Evgeniya; von Schuckmann, Karina; Kharecha, Pushker; Legrande, Allegra N.; Bauer, Michael; Lo, Kwok-Wai

    2016-01-01

    warmer than today. Ice melt cooling of the North Atlantic and Southern oceans increases atmospheric temperature gradients, eddy kinetic energy and baroclinicity, thus driving more powerful storms. The modeling, paleoclimate evidence, and ongoing observations together imply that 2 C global warming above the preindustrial level could be dangerous. Continued high fossil fuel emissions this century are predicted to yield (1) cooling of the Southern Ocean, especially in the Western Hemisphere; (2) slowing of the Southern Ocean overturning circulation, warming of the ice shelves, and growing ice sheet mass loss; (3) slowdown and eventual shutdown of the Atlantic overturning circulation with cooling of the North Atlantic region; (4) increasingly powerful storms; and (5) nonlinearly growing sea level rise, reaching several meters over a timescale of 50-150 years. These predictions, especially the cooling in the Southern Ocean and North Atlantic with markedly reduced warming or even cooling in Europe, differ fundamentally from existing climate change assessments. We discuss observations and modeling studies needed to refute or clarify these assertions.

  14. Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous

    Science.gov (United States)

    Hansen, James; Sato, Makiko; Hearty, Paul; Ruedy, Reto; Kelley, Maxwell; Masson-Delmotte, Valerie; Russell, Gary; Tselioudis, George; Cao, Junji; Rignot, Eric; Velicogna, Isabella; Tormey, Blair; Donovan, Bailey; Kandiano, Evgeniya; von Schuckmann, Karina; Kharecha, Pushker; Legrande, Allegra N.; Bauer, Michael; Lo, Kwok-Wai

    2016-03-01

    C warmer than today. Ice melt cooling of the North Atlantic and Southern oceans increases atmospheric temperature gradients, eddy kinetic energy and baroclinicity, thus driving more powerful storms. The modeling, paleoclimate evidence, and ongoing observations together imply that 2 °C global warming above the preindustrial level could be dangerous. Continued high fossil fuel emissions this century are predicted to yield (1) cooling of the Southern Ocean, especially in the Western Hemisphere; (2) slowing of the Southern Ocean overturning circulation, warming of the ice shelves, and growing ice sheet mass loss; (3) slowdown and eventual shutdown of the Atlantic overturning circulation with cooling of the North Atlantic region; (4) increasingly powerful storms; and (5) nonlinearly growing sea level rise, reaching several meters over a timescale of 50-150 years. These predictions, especially the cooling in the Southern Ocean and North Atlantic with markedly reduced warming or even cooling in Europe, differ fundamentally from existing climate change assessments. We discuss observations and modeling studies needed to refute or clarify these assertions.

  15. Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations that 2C Global Warming Could Be Dangerous

    Science.gov (United States)

    Hansen, J.; Sato, Makiko; Hearty, Paul; Ruedy, Reto; Kelley, Maxwell; Masson-Delmotte, Valerie; Russell, Gary; Tselioudis, George; Cao, Junji; Rignot, Eric; hide

    2016-01-01

    warmer than today. Ice melt cooling of the North Atlantic and Southern oceans increases atmospheric temperature gradients, eddy kinetic energy and baroclinicity, thus driving more powerful storms. The modeling, paleoclimate evidence, and ongoing observations together imply that 2 C global warming above the preindustrial level could be dangerous. Continued high fossil fuel emissions this century are predicted to yield (1) cooling of the Southern Ocean, especially in the Western Hemisphere; (2) slowing of the Southern Ocean overturning circulation, warming of the ice shelves, and growing ice sheet mass loss; (3) slowdown and eventual shutdown of the Atlantic overturning circulation with cooling of the North Atlantic region; (4) increasingly powerful storms; and (5) nonlinearly growing sea level rise, reaching several meters over a timescale of 50-150 years. These predictions, especially the cooling in the Southern Ocean and North Atlantic with markedly reduced warming or even cooling in Europe, differ fundamentally from existing climate change assessments. We discuss observations and modeling studies needed to refute or clarify these assertions.

  16. Uncertainties in sea level projections on twenty-year timescales

    Science.gov (United States)

    Vinogradova, Nadya; Davis, James; Landerer, Felix; Little, Chris

    2016-04-01

    Regional decadal changes in sea level are governed by various processes, including ocean dynamics, gravitational and solid earth responses, mass loss of continental ice, and other local coastal processes. In order to improve predictions and physical attribution in decadal sea level trends, the uncertainties of each processes must be reflected in the sea level calculations. Here we explore uncertainties in predictions of the decadal and bi-decadal changes in regional sea level induced by the changes in ocean dynamics and associated redistribution of heat and freshwater (often referred to as dynamic sea level). Such predictions are typically based on the solutions from coupled atmospheric and oceanic general circulation models, including a suite of climate models participating in phase 5 of the Coupled Model Intercompasion Project (CMIP5). Designed to simulate long-term ocean variability in response to warming climate due to increasing green-house gas concentration ("forced" response), CMIP5 are deficient in simulating variability at shorter time scales. In contrast, global observations of sea level are available during a relatively short time span (e.g., twenty-year altimetry records), and are dominated by an "unforced" variability that occurs freely (internally) within the climate system. This makes it challenging to examine how well observations compare with model simulations. Therefore, here we focus on patterns and spatial characteristics of projected twenty-year trends in dynamic sea level. Based on the ensemble of CMIP5 models, each comprising a 240-year run, we compute an envelope of twenty-year rates, and analyze the spread and spatial relationship among predicted rates. An ensemble root-mean-square average exhibits large-scale spatial patterns, with the largest uncertainties found over mid and high latitudes that could be attributed to the changes in wind patterns and buoyancy forcing. To understand and parameterize spatial characteristics of the

  17. 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

  18. Seasonal sea level extremes in the Mediterranean Sea and at the Atlantic European coasts

    Directory of Open Access Journals (Sweden)

    M. N. Tsimplis

    2010-07-01

    Full Text Available Hourly sea level data from tide gauges and a barotropic model are used to explore the spatial and temporal variability of sea level extremes in the Mediterranean Sea and the Atlantic coasts of the Iberian peninsula on seasonal time scales. Significant spatial variability is identified in the observations in all seasons. The Atlantic stations show larger extreme values than the Mediterranean Sea primarily due to the tidal signal. When the tidal signal is removed most stations have maximum values of less than 90 cm occurring in winter or autumn. The maxima in spring and summer are less than 60 cm in most stations. The wind and atmospheric forcing contributes about 50 cm in the winter and between 20–40 cm in the other seasons. In the western Mediterranean the observed extreme values are less than 50 cm, except near the Strait of Gibraltar. Direct atmospheric forcing contributes significantly to sea level extremes. Maximum sea level values due to atmospheric forcing reach in some stations 45 cm during the winter. During the summer the contribution of the direct atmospheric forcing is between 10–20 cm. The Adriatic Sea shows a resonant behaviour with maximum extreme observed sea level values around 200 cm found at the northern part. Trends in the 99.9% percentiles are present in several areas, however most of them are removed when the 50% percentile is subtracted indicating that changes in the extremes are in line with mean sea level change. The North Atlantic Oscillation and the Mediterranean Oscillation Index are well correlated with the changes in the 99.9% winter values in the Atlantic, western Mediterranean and the Adriatic stations. The correlation of the NAO and the MOI indices in the Atlantic and western Mediterranean is significant in the autumn too. The correlations between the NAO and MOI index and the changes in the sea level extremes become insignificant when the 50% percentile is removed indicating again that changes in extremes

  19. Mean and extreme sea level changes in the southwestern Baltic Sea

    Science.gov (United States)

    Schmidt, Jessica; Patzke, Justus; Dangendorf, Sönke; Arns, Arne; Jensen, Jürgen; Fröhle, Peter

    2016-04-01

    In this contribution an overview over the BMBF project AMSeL_Ostsee (2015-2018) for the assessment of mean and extreme sea level changes over the past 150 years in the southwestern Baltic Sea is presented. We compile several high resolution tide gauge records provided by the Water and Shipping Administration (WSV) along the German Baltic Sea coastline and merge them in internationally available data bases (UHSLC, PSMSL, and data officially available at national authorities). In addition, we make efforts in digitizing historical records to expand the number of available data sets in this complex and vulnerable coastal region. To separate absolute from relative long-term changes in sea level the vertical land motion (VLM) at specific sites is assessed. Possible sources of VLM are independently assessed by using different state-of-the-art approaches, that is: Glacial Isostatic Adjustment (GIA) modelled by viscoelastic Earth models, GPS derived VLM, and the difference between tide gauge and nearby satellite altimetry. The VLM corrected tide gauge records are further assessed for linear and non-linear trends as well as possible acceleration/deceleration patterns by applying advanced time series models such as Singular System Analysis (SSA) combined with a Monte-Carlo-Autoregressive-Padding approach (Wahl et al., 2010). These trend assessments are applied to mean and extreme sea levels independently to prove whether observed changes in extremes are either due to an underlying trend on mean sea levels or changes in storminess. References: Wahl, T., Jensen, J., Frank, T. (2011): On analysing sea level rise in the German Bight since 1844, NHESS, 10, 171-179.

  20. Ice-sheet modelling characteristics in sea-level-based temperature reconstructions over the last glacial cycle

    NARCIS (Netherlands)

    Wilschut, F.; Bintanja, R.; van de Wal, R.S.W.

    2006-01-01

    A widely used method for investigating palaeotemperatures is to analyze local proxy records (e.g. ice cores or deep-sea sediment cores). The interpretation of these records is often not straightforward, and global or hemispheric means cannot be deduced from local estimates because of large spatial v

  1. Long-period sea-level variations in the Mediterranean

    Science.gov (United States)

    Zerbini, Susanna; Raicich, Fabio; Bruni, Sara; del Conte, Sara; Errico, Maddalena; Prati, Claudio; Santi, Efisio

    2016-04-01

    Since the beginning of its long-lasting lifetime, the Wegener initiative has devoted careful consideration to studying sea-level variations/changes across the Mediterranean Sea. Our study focuses on several long-period sea-level time series (from end of 1800 to 2012) acquired in the Mediterranean by tide gauge stations. In general, the analysis and interpretation of these data sets can provide an important contribution to research on climate change and its impacts. We have analyzed the centennial sea-level time series of six fairly well documented tide gauges. They are: Marseille, in France, Alicante in Spain, Genoa, Trieste, Venice and Marina di Ravenna (formerly Porto Corsini), in Italy. The data of the Italian stations of Marina di Ravenna and Venice clearly indicate that land subsidence is responsible for most of the observed rate of relative sea level rise. It is well known that, in the two areas, subsidence is caused by both natural processes and human activities. For these two stations, using levelling data of benchmarks at, and/or close to, the tide gauges, and for the recent years, also GPS and InSAR height time series, modelling of the long-period non-linear behavior of subsidence was successfully accomplished. After removing the land vertical motions, the estimate of the linear long-period sea-level rise at all six stations yielded remarkably consistent values, between +1,2 and +1,3 mm/yr, with associated errors ranging from ±0,2 to ±0,3 mm/yr (95% confidence interval), which also account for the statistical autocorrelation of the time series. These trends in the Mediterranean area are lower than the global mean rate of 1,7±0,2 mm/yr (1901-2010) presented by the IPCC in its 5th Assessment Report; however, they are in full agreement with a global mean sea-level rise estimate, over the period 1901-1990, recently published by Hay et al. (2015, doi:10.1038/nature14093) and obtained using probabilistic techniques that combine sea-level records with physics

  2. Coastal subsidence and relative sea level rise

    Science.gov (United States)

    Ingebritsen, Steven E.; Galloway, Devin L.

    2014-01-01

    Subsurface fluid-pressure declines caused by pumping of groundwater or hydrocarbons can lead to aquifer-system compaction and consequent land subsidence. This subsidence can be rapid, as much as 30 cm per year in some instances, and large, totaling more than 13 m in extreme examples. Thus anthropogenic subsidence may be the dominant contributor to relative sea-level rise in coastal environments where subsurface fluids are heavily exploited. Maximum observed rates of human-induced subsidence greatly exceed the rates of natural subsidence of unconsolidated sediments (~0.1–1 cm yr−1) and the estimated rates of ongoing global sea-level rise (~0.3 cm yr−1).

  3. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 projections of shoreline change due to 21st century sea level rise

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Summary: This dataset contains projections of shoreline positions and uncertainty bands for future scenarios of sea-level rise. Projections were made using...

  4. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 projections of shoreline change due to 21st century sea level rise

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Summary: This dataset contains projections of shoreline positions and uncertainty bands for future scenarios of sea-level rise. Projections were made using...

  5. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 projections of coastal cliff retreat due to 21st century sea-level rise

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Summary: This dataset contains projections of coastal cliff-retreat rates and positions for future scenarios of sea-level rise (SLR). Projections were made using...

  6. CoSMoS (Coastal Storm Modeling System) Southern California v3.0 projections of coastal cliff retreat due to 21st century sea-level rise

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Summary: This dataset contains projections of coastal cliff-retreat rates and positions for future scenarios of sea-level rise (SLR). Projections were made using...

  7. Sea Level Rise and Subsidence in the Gulf of Thailand

    Science.gov (United States)

    Niemnil, Sommart

    In the Thailand -EC GEO2TECDI-SONG Project we investigate the sea level change and vertical land motion in Thailand. First, Bangkok is situated in river delta and average height is closed to sea level. Second, it is subsiding due to ground water extraction. Third, it is experiencing post-seismic motion due to nearby mega thrust earthquakes and fourth, it suffers from rising of sea levels due to global climate change. This poses a serious threat on Thai society and economy. Before mitigation methods can be devised we aim at charting, qualifying and quantifying all contributing effects by the use of satellite altimetry, GNSS, InSAR techniques and combining results with the in situ observations like tide gauge and with geophysical modeling. Adding GPS based vertical land motion to the tide gauge sea level registration reveals the absolute sea level change, which is nicely confirmed by altimetry. We find an average absolute rise of 3.5 mm/yr + 0.7, but nears mouth of Chao Praya River (Bangkok) and the Mekong delta (Ho Chi Min City), this mounts to 4 to 5 mm/yr, faster than global average. This is reinforced when accounting for the tectonic subsidence that resulted from 2004 9.1Mw Sumatra/Andaman earthquake; from 2005 onwards we find downfall in the order of 10 mm/yr. RADARSAT InSAR analyses show subsidence rates up to 25 mm/yr at many places along coastal Bangkok.

  8. A projection of future sea level

    OpenAIRE

    1989-01-01

    Evidence is reviewed that suggests faster sea-level rise when climate gets warmer. Four processes appear as dominating on a time scale of decades to centuries: melting of mountain glaciers and small ice caps, changes in the mass balance of the large polar ice sheets (Greenland, Antarctica), possible ice-flow instabilities (in particular on the West Antarctic Ice Sheet), and thermal expansion of ocean water. For a given temperature scenario, an attempt is made to estimate the different contrib...

  9. Gulf of Mexico sea level curve

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, W.F.; Demirpolat, S. (Florida State Univ., Tallahassee (USA)); Stapor, F.W. (Tennessee Technological Univ., Cookeville (USA)); Alvarez, L. (Universidad Nacional Autonoma de Mexico (Mexico))

    1989-09-01

    Beach ridge plains on four sides of the Gulf of Mexico produced a new, better sea level history for late Holocene time: St. Vincent Island, Florida panhandle; Sanibel Island, lower peninsula of Florida; Mesa del Gavilan, east of Brownsville, Texas; and Isla del Carmen, in the state of Campeche, Mexico. On St. Vincent Island there are more than 300 data points (elevation and relative age), each taken from a beach ridge or a swale. These ridges and swales can be grouped in sets; some sets stand high, and some are low. Their boundaries mark rises and drops of sea level. The St. Vincent Island data fall in a continuous time sequence. The types of data available on and adjacent to this island are topographic (plane-table work), sedimentological (high-precision grain size parameters), photographic (air photos), and pedologic. All of these data agree in meaning, as far as sea level history is concerned. They provide a record of changes, both up and down, in the range of about 1 m to perhaps as much as 3-4 m. Three rises and two drops in the last 6,000 years are obvious. Changes as small as 10-50 cm probably cannot be detected by the methods at hand, but it is highly unlikely, with hundreds of data points in one small study area, that major changes (1 m or more) have been overlooked. The latest change was a rise, about 800 years ago.

  10. 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...

  11. 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

  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. Integrating Science and Management - Evaluation of a Collaborative Model to Accelerate the Transition of Sea Level Rise Research Results into Application

    Science.gov (United States)

    Kidwell, D.; DeLorme, D.; Lewitus, A.

    2015-12-01

    The development and implementation of applied research programs that maximize stakeholder collaboration and utility is a well-documented struggle for funding agencies. In 2007, NOAA initiated multi-year stakeholder engagement process to develop a regional-scale, inter-disciplinary research project that resulted in a novel approach to accelerate the application of research results into management. This process culminated in a 2009 federal funding opportunity and resultant 6-year Ecological Effects of Sea Level Rise-Northern Gulf of Mexico (EESLR-NGOM) project focused on the dynamic integration of biological models (wetlands and oysters) with inundation and storm surge models at three National Estuarine Research Reserves in Florida, Alabama, and Mississippi. The project implemented a co-management approach between a traditional principle investigator (PI) and newly created applications co-PI that led a management advisory committee. Our goal was to provide the dedicated funding and infrastructure necessary to ensure the initial relevancy of the proposed project results, to guide ongoing research efforts, and to aid the efficient incorporation of key scientific results and tools into direct management application. As the project nears completion in 2016 and modeling applications reach maturity, this presentation will discuss the programmatic approach that resulted in EESLR-NGOM as well as an evaluation of nearly 6-years of collaborative science. This evaluation will focus on the funding agency perspective, with an emphasis on assessing the pros and cons of project implementation to establish lessons-learned for related collaborative science efforts. In addition, with increased attention in the Gulf of Mexico on projected sea level rise impacts to coastal ecosystem restoration and management, a core benchmark for this evaluation will be the use of project models and tools by coastal managers and planners at local, state, and/or federal agencies.

  14. 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)...

  15. 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.

  16. THE INEXPENSIVE DEVICE FOR SEA LEVEL MEASUREMENTS

    Directory of Open Access Journals (Sweden)

    A. Annunziato

    2015-10-01

    Full Text Available A new mareograph device has been designed at the Joint Research Centre (JRC of the European Commission (EC in order improve the sea level network in use for the Tsunami Hazard monitoring in the Mediterranean Sea and in the North Atlantic area (NEAMTWS area of UNESCO. The instrument has the characteristic to be cheap and very effective but its reliability, duration and quality need to be determined and qualified. For this reason a number of experimental campaigns are being conducted, whose first results are presented here. In collaboration with the UNESCO/IOC (Intergovernmental Oceanographic Commission, responsible of the definition of the Tsunami Warning System of this geographical area, a set of 20 devices has been offered by JRC for a period of 1 year of testing of the devices; the surveys for the installation of the devices is under way and the installation should be completed by the end of 2015.

  17. 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

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

    Science.gov (United States)

    Frederikse, Thomas; Riva, Riccardo; Slobbe, Cornelis; Broerse, Taco; Verlaan, Martin

    2016-03-01

    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 teleconnection patterns. This model has two advantages over the classical least-squares method that uses regression to explain variations due to known processes: a seasonal cycle with time-varying phase and amplitude can be estimated, and the trend is allowed to vary over time. This time-varying trend consists of a secular trend and low-frequency variability that is not explained by any other term in the model. As a test case, we have used tide gauge data from stations around the North Sea over the period 1980-2013. We compare a model that only estimates a trend with two models that also remove intra-annual variability: one by means of time series of wind stress and sea level pressure, and one by using a two-dimensional hydrodynamic model. The last two models explain a large part of the variability, which significantly improves the accuracy of the estimated time-varying trend. The best results are obtained with the hydrodynamic model. We find a consistent low-frequency sea level signal in the North Sea, which can be linked to a steric signal over the northeastern part of the Atlantic.

  19. Potential for bias in 21st century semiempirical sea level projections

    DEFF Research Database (Denmark)

    Jevrejeva, S.; Moore, J. C.; Grinsted, A.

    2012-01-01

    We examine the limitations of a semiempirical model characterized by a sea level projection of 73 cm with RCP4.5 scenario by 2100. Calibrating the model with data to 1990 and then simulating the period 1993-2009 produces sea level in close agreement with acceleration in sea level rise observed...... and dynamics of Greenland ice sheet made contributions to the sea level rise in the early 20th century and therefore are included within the semiempirical model calibration period and hence are included in semiempirical sea level projections by 2100. Antarctic response is probably absent from semiempirical...... models, which will lead to a underestimate in sea level rise if, as is probable, Antarctica loses mass by 2100....

  20. 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.

    that are induced by local and remote meteorological forcings. The sea level residue (i.e. measured sea level minus the astronomically induced sea level) in this region is particularly by the local wind pattern and air pressure variations. The observed response...

  1. Sea level change under IPCC-A2 scenario in Bohai, Yellow, and East China Seas

    Institute of Scientific and Technical Information of China (English)

    Chang-lin CHEN; Jun-cheng ZUO; Mei-xiang CHEN; Zhi-gang GAO; C-K SHUM

    2014-01-01

    Because of the environmental and socioeconomic impacts of anthropogenic sea level rise (SLR), it is very important to understand the processes leading to past and present SLRs towards more reliable future SLR projections. A regional ocean general circulation model (ROGCM), with a grid refinement in the Bohai, Yellow, and East China Seas (BYECSs), was set up to project SLR induced by the ocean dynamic change in the 21st century. The model does not consider the contributions from ice sheets and glacier melting. Data of all forcing terms required in the model came from the simulation of the Community Climate System Model version 3.0 (CCSM3) under the International Panel on Climate Change (IPCC)-A2 scenario. Simulation results show that at the end of the 21st century, the sea level in the BYECSs will rise about 0.12 to 0.20 m. The SLR in the BYECSs during the 21st century is mainly caused by the ocean mass redistribution due to the ocean dynamic change of the Pacific Ocean, which means that water in the Pacific Ocean tends to move to the continental shelves of the BYECSs, although the local steric sea level change is another factor.

  2. Sea level change under IPCC-A2 scenario in Bohai, Yellow, and East China Seas

    Directory of Open Access Journals (Sweden)

    Chang-lin CHEN

    2015-10-01

    Full Text Available Because of the environmental and socioeconomic impacts of anthropogenic sea level rise (SLR, it is very important to understand the processes leading to past and present SLRs towards more reliable future SLR projections. A regional ocean general circulation model (ROGCM, with a grid refinement in the Bohai, Yellow, and East China Seas (BYECSs, was set up to project SLR induced by the ocean dynamic change in the 21st century. The model does not consider the contributions from ice sheets and glacier melting. Data of all forcing terms required in the model came from the simulation of the Community Climate System Model version 3.0 (CCSM3 under the International Panel on Climate Change (IPCC-A2 scenario. Simulation results show that at the end of the 21st century, the sea level in the BYECSs will rise about 0.12 to 0.20 m. The SLR in the BYECSs during the 21st century is mainly caused by the ocean mass redistribution due to the ocean dynamic change of the Pacific Ocean, which means that water in the Pacific Ocean tends to move to the continental shelves of the BYECSs, although the local steric sea level change is another factor.

  3. Spatial variations of sea-level rise and impacts: an application of DIVA

    OpenAIRE

    Brown, S; Nicholls, R.J.; Lowe, J A; Hinkel, J.

    2013-01-01

    Due to complexities of creating sea-level rise scenarios, impacts of climate-induced sea-level rise are often produced from a limited number of models assuming a global uniform rise in sea level. A greater number of models, including those with a pattern reflecting regional variations would help to assure reliability and a range of projections, indicating where models agree and disagree. This paper determines how nine new patterned-scaled sea-level rise scenarios (plus the uniform and pattern...

  4. Sea-Level Rise by 2100

    Digital Repository Service at National Institute of Oceanography (India)

    Church, J.A; Clark, P.A; 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.

    VOL 342 20 DECEMBER 2013 1445 LETTERS edited by Jennifer Sills 1462 COMMENTARY LETTERS I BOOKS I POLICY FORUM I EDUCATION FORUM I PERSPECTIVES 1452 Defending the nest IBI Prize Essay C R E D IT : A N D R E W M A N D E M A K E R /W IK IM E... D IA C O M M O N S Sea-Level Rise by 2100 IN HIS NEWS AND ANALYSIS PIECE REPORTING ON THE NEWLY RELEASED FIFTH ASSESSMENT report (AR5) by Working Group I (WGI) of the Intergovernmental Panel on Climate Change (IPCC) (“A Stronger IPCC Report,” 4...

  5. Application of a Coupled Vegetation Competition and Groundwater Simulation Model to Study Effects of Sea Level Rise and Storm Surges on Coastal Vegetation

    Directory of Open Access Journals (Sweden)

    Su Yean Teh

    2015-09-01

    Full Text Available Global climate change poses challenges to areas such as low-lying coastal zones, where sea level rise (SLR and storm-surge overwash events can have long-term effects on vegetation and on soil and groundwater salinities, posing risks of habitat loss critical to native species. An early warning system is urgently needed to predict and prepare for the consequences of these climate-related impacts on both the short-term dynamics of salinity in the soil and groundwater and the long-term effects on vegetation. For this purpose, the U.S. Geological Survey’s spatially explicit model of vegetation community dynamics along coastal salinity gradients (MANHAM is integrated into the USGS groundwater model (SUTRA to create a coupled hydrology–salinity–vegetation model, MANTRA. In MANTRA, the uptake of water by plants is modeled as a fluid mass sink term. Groundwater salinity, water saturation and vegetation biomass determine the water available for plant transpiration. Formulations and assumptions used in the coupled model are presented. MANTRA is calibrated with salinity data and vegetation pattern for a coastal area of Florida Everglades vulnerable to storm surges. A possible regime shift at that site is investigated by simulating the vegetation responses to climate variability and disturbances, including SLR and storm surges based on empirical information.

  6. Application of a coupled vegetation competition and groundwater simulation model to study effects of sea level rise and storm surges on coastal vegetation

    Science.gov (United States)

    Teh, Su Yean; Turtora, Michael; DeAngelis, Don; Jiang Jiang,; Pearlstine, Leonard G.; Smith, Thomas; Koh, Hock Lye

    2015-01-01

    Global climate change poses challenges to areas such as low-lying coastal zones, where sea level rise (SLR) and storm-surge overwash events can have long-term effects on vegetation and on soil and groundwater salinities, posing risks of habitat loss critical to native species. An early warning system is urgently needed to predict and prepare for the consequences of these climate-related impacts on both the short-term dynamics of salinity in the soil and groundwater and the long-term effects on vegetation. For this purpose, the U.S. Geological Survey’s spatially explicit model of vegetation community dynamics along coastal salinity gradients (MANHAM) is integrated into the USGS groundwater model (SUTRA) to create a coupled hydrology–salinity–vegetation model, MANTRA. In MANTRA, the uptake of water by plants is modeled as a fluid mass sink term. Groundwater salinity, water saturation and vegetation biomass determine the water available for plant transpiration. Formulations and assumptions used in the coupled model are presented. MANTRA is calibrated with salinity data and vegetation pattern for a coastal area of Florida Everglades vulnerable to storm surges. A possible regime shift at that site is investigated by simulating the vegetation responses to climate variability and disturbances, including SLR and storm surges based on empirical information.

  7. Storminess helps coastal marshes withstand sea level rise

    Science.gov (United States)

    Balcerak, Ernie

    2013-03-01

    Rising sea levels are predicted to threaten many coastal sea marshes around the world in the coming decades as the Earth's climate warms. In addition to accelerating sea level rise, global climate change is predicted to increase the frequency and severity of storms in many places around the world. However, few studies have taken into account how an increased storminess might affect the ability of coastal marshes to withstand sea level rise.

  8. Impact of accelerated future global mean sea level rise on hypoxia in the Baltic Sea

    Science.gov (United States)

    Meier, H. E. M.; Höglund, A.; Eilola, K.; Almroth-Rosell, E.

    2017-07-01

    Expanding hypoxia is today a major threat for many coastal seas around the world and disentangling its drivers is a large challenge for interdisciplinary research. Using a coupled physical-biogeochemical model we estimate the impact of past and accelerated future global mean sea level rise (GSLR) upon water exchange and oxygen conditions in a semi-enclosed, shallow sea. As a study site, the Baltic Sea was chosen that suffers today from eutrophication and from dead bottom zones due to (1) excessive nutrient loads from land, (2) limited water exchange with the world ocean and (3) perhaps other drivers like global warming. We show from model simulations for the period 1850-2008 that the impacts of past GSLR on the marine ecosystem were relatively small. If we assume for the end of the twenty-first century a GSLR of +0.5 m relative to today's mean sea level, the impact on the marine ecosystem may still be small. Such a GSLR corresponds approximately to the projected ensemble-mean value reported by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. However, we conclude that GSLR should be considered in future high-end projections (>+1 m) for the Baltic Sea and other coastal seas with similar hydrographical conditions as in the Baltic because GSLR may lead to reinforced saltwater inflows causing higher salinity and increased vertical stratification compared to present-day conditions. Contrary to intuition, reinforced ventilation of the deep water does not lead to overall improved oxygen conditions but causes instead expanded dead bottom areas accompanied with increased internal phosphorus loads from the sediments and increased risk for cyanobacteria blooms.

  9. Impact of accelerated future global mean sea level rise on hypoxia in the Baltic Sea

    Science.gov (United States)

    Meier, H. E. M.; Höglund, A.; Eilola, K.; Almroth-Rosell, E.

    2016-08-01

    Expanding hypoxia is today a major threat for many coastal seas around the world and disentangling its drivers is a large challenge for interdisciplinary research. Using a coupled physical-biogeochemical model we estimate the impact of past and accelerated future global mean sea level rise (GSLR) upon water exchange and oxygen conditions in a semi-enclosed, shallow sea. As a study site, the Baltic Sea was chosen that suffers today from eutrophication and from dead bottom zones due to (1) excessive nutrient loads from land, (2) limited water exchange with the world ocean and (3) perhaps other drivers like global warming. We show from model simulations for the period 1850-2008 that the impacts of past GSLR on the marine ecosystem were relatively small. If we assume for the end of the twenty-first century a GSLR of +0.5 m relative to today's mean sea level, the impact on the marine ecosystem may still be small. Such a GSLR corresponds approximately to the projected ensemble-mean value reported by the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. However, we conclude that GSLR should be considered in future high-end projections (>+1 m) for the Baltic Sea and other coastal seas with similar hydrographical conditions as in the Baltic because GSLR may lead to reinforced saltwater inflows causing higher salinity and increased vertical stratification compared to present-day conditions. Contrary to intuition, reinforced ventilation of the deep water does not lead to overall improved oxygen conditions but causes instead expanded dead bottom areas accompanied with increased internal phosphorus loads from the sediments and increased risk for cyanobacteria blooms.

  10. Drivers of Holocene sea-level change - using a global database of relative sea-level records from the Northern and Southern Hemisphere

    Science.gov (United States)

    Horton, Benjamin; Khan, Nicole; Ashe, Erica; Kopp, Robert

    2016-04-01

    Many factors give rise to relative sea-level (RSL) changes that are far from globally uniform. For example, spatially variable sea-level responses arise because of the exchange of mass between ice sheets and oceans. Gravitational, flexural, and rotational processes generate a distinct spatial pattern - or "fingerprint" - of sea-level change associated with each shrinking land ice mass. As a land ice mass shrinks, sea-level rise is greater in areas geographically distal to the ice mass than in areas proximal to it, in large part because the gravitational attraction between the ice mass and the ocean is reduced. Thus, the U.S. mid-Atlantic coastline experiences about 50% of the global average sea-level-rise due to Greenland Ice Sheet melt, but about 120% of the global average due to West Antarctic Ice Sheet melt. Separating the Greenland and Antarctic ice sheet contributions during the past 7,000 years requires analysis of sea-level changes from sites in the northern and southern hemisphere. Accordingly we present a global sea-level database for the Holocene to which we apply a hierarchical statistical model to: (1) estimate the Global Mean Sea Level Signal; (2) quantify rates of change; (3) compare rates of change among sites, including full quantification of the uncertainty in their differences; and (4) test hypotheses about the sources of meltwater through their sea-level fingerprints.

  11. Climate Sensitivity, Sea Level, and Atmospheric CO2

    CERN Document Server

    Hansen, James; Russell, Gary; Kharecha, Pushker

    2012-01-01

    Cenozoic temperature, sea level and CO2 co-variations provide insights into climate sensitivity to external forcings and sea level sensitivity to climate change. Pleistocene climate oscillations imply a fast-feedback climate sensitivity 3 {\\pm} 1 {\\deg}C for 4 W/m2 CO2 forcing for the average of climate states between the Holocene and Last Glacial Maximum (LGM), the error estimate being large and partly subjective because of continuing uncertainty about LGM global surface climate. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify total Earth system sensitivity. Ice sheet response time is poorly defined, but we suggest that hysteresis and slow response in current ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state-dependence of climate sensitivity, finding a strong increase in sensitivity when global temperature reaches early Cenozoic and higher levels, as increased water vapor eliminates the tropopause. It follows that...

  12. Revisiting sea level changes in the North Sea during the Anthropocene

    Science.gov (United States)

    Jensen, Jürgen; Dangendorf, Sönke; Wahl, Thomas; Niehüser, Sebastian

    2016-04-01

    The North Sea is one of the best instrumented ocean basins in the world. Here we revisit sea level changes in the North Sea region from tide gauges, satellite altimetry, hydrographic profiles and ocean reanalysis data from the beginning of the 19th century to present. This includes an overview of the sea level chapter of the North Sea Climate Change Assessment (NOSCCA) complemented by results from more recent investigations. The estimates of long-term changes from tide gauge records are significantly affected by vertical land motion (VLM), which is related to both the large-scale viscoelastic response of the solid earth to ice melting since the last deglaciation and local effects. Removing VLM (estimated from various data sources such as GPS, tide gauge minus altimetry and GIA) significantly reduces the spatial variability of long-term trends in the basin. VLM corrected tide gauge records suggest a transition from relatively moderate changes in the 19th century towards modern trends of roughly 1.5 mm/yr during the 20th century. Superimposed on the long-term changes there is a considerable inter-annual to multi-decadal variability. On inter-annual timescales this variability mainly reflects the barotropic response of the ocean to atmospheric forcing with the inverted barometer effect dominating along the UK and Norwegian coastlines and wind forcing controlling the southeastern part of the basin. The decadal variability is mostly remotely forced and dynamically linked to the North Atlantic via boundary waves in response to long-shore winds along the continental slope. These findings give valuable information about the required horizontal resolution of ocean models and the necessary boundary conditions and are therefore important for the dynamical downscaling of sea level projections for the North Sea coastlines.

  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. Long Term Sea Level Change and Water Mass Balance in the South China Sea

    Institute of Scientific and Technical Information of China (English)

    RONG Zengrui; LIU Yuguang; ZONG Haibo; XIU Peng

    2009-01-01

    Sea level anomalies observed by altimeter during the 1993-2006 period, thermosterie sea level anomalies estimated by using subsurface temperature data produced by Ishii and SODA reanalysis data, tide gauge records and HOAPS freshwater flux data were analyzed to investigate the long term sea level change and the water mass balance in the South China Sea. The altimeter-observed sea level showed a rising rate of (3.5±0.9)mm yr-1 during the period 1993-2006, but this figure was considered to have been highly distorted by the relatively short time interval and the large inter-decadal variability, which apparently exists in both the thermosteric sea level and the observed sea level. Long term thermosteric sea level from 1945 to 2004 gave a rising rate of 0.15±0.06 mmyr-1. Tide gauge data revealed this discrepancy and the regional distributions of the sea-level trends. Both the 'real' and the thermosteric sea level showed a good correspondence to ENSO: decreasing during E1 Nifio years and increasing during La Nina years. Amplitude and phase differences between the 'real' sea level and the thermosteic sea level were substantially revealed on both seasonal and interannual time scales. As one of the possible factors, the freshwater flux might play an important role in balancing the water mass.

  15. ICE-6G models of postglacial relative sea-level history applied to Holocene coral reef and mangrove records of the western Caribbean

    Science.gov (United States)

    Toscano, M. A.; Peltier, W. R.; Drummond, R.; Gonzalez, J.

    2012-12-01

    Fossil coral reefs and mangrove peat accumulations at western Caribbean sites along a latitudinal gradient from the Florida Keys through Belize and Panama provide dated and interpreted 8,000 year Holocene sea-level records for comparison with RSL predictions of the ICE-6G (VM5A, VM5B; L90) models of glacio-hydro-isostatic adjustment, with and without rotational feedback. These presumably passive continental margin sites provide the means to establish a N-S spatial trend in the varying influences of GIA, eustatic components of Holocene sea level, extent of forebulge collapse and influence of rotational feedback over a 20° latitudinal range. Previous ICE6G (VM5A) model-coral data comparisons for St Croix, USVI, Antigua, Martinique and Barbados (Toscano, Peltier and Drummond, 2011, QSR) along the eastern Caribbean plate and island arc illustrated the close model-data compatibility, the influence of rotational feedback acting as a significant factor in reducing misfits, and the need for high quality in situ data to confirm the extension of the proglacial forebulge into tropical latitudes. The gradient of western Caribbean continental shelf sites comprises a much more varied range of model-data relationships based on extensive combined Acropora palmata (reef crest coral) and Rhizophora mangle (microtidal mangrove) peat datasets in all cases. Starting at the northernmost region with the Florida Keys, there exist negative model misfits to the data, suggesting the possibility of a positive tectonic overprint upon expectations related to the glacial isostatic adjustment process acting alone, even though this region is normally believed to be tectonically stable. The largest multi-proxy database from Belize supports the likelihood of increasing rates of subsidence from north to south in the Belize Lagoon, which may account for numerous positive GIA model-data misfits. The southernmost site at Panama is most similar to Belize in the possible nature of tectonic influences on

  16. A Heavy Sea Fog Event over the Yellow Sea in March 2005:Analysis and Numerical Modeling

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, a heavy sea fog episode that occurred over the Yellow Sea on 9 March 2005 is investigated.The sea fog patch, with a spatial scale of several hundred kilometers at its mature stage, reduced visibility along the Shandong Peninsula coast to 100 m or much less at some sites. Satellite images, surface observations and soundings at islands and coasts, and analyses from the Japan Meteorology Agency (JMA) are used to describe and analyze this event. The analysis indicates that this sea fog can be categorized as advection cooling fog. The main features of this sea fog including fog area and its movement are reasonably reproduced by the Fifth-generation Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5). Model results suggest that the formation and evolution of this event can be outlined as:(1) southerly warm/moist advection of low-level air resulted in a strong sea-surface-based inversion with a thickness of about 600 m; (2) when the inversion moved from the warmer East Sea to the colder Yellow Sea, a thermal internal boundary layer (TIBL) gradually formed at the base of the inversion while the sea fog grew in response to cooling and moistening by turbulence mixing; (3) the sea fog developed as the TIBL moved northward and (4) strong northerly cold and dry wind destroyed the TIBL and dissipated the sea fog. The principal findings of this study are that sea fog forms in response to relatively persistent southerly warm/moist wind and a cold sea surface, and that turbulence mixing by wind shear is the primary mechanism for the cooling and moistening the marine layer. In addition, the study of sensitivity experiments indicates that deterministic numerical modeling offers a promising approach to the prediction of sea fog over the Yellow Sea but it may be more efficient to consider ensemble numerical modeling because of the extreme sensitivity to model input.

  17. 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...... show quite different responses to sea-level rise. The southernmost island Rømø has survived 17 m of sea-level rise at the same position illustrating the control from sediment supply; whereas the northernmost island Skallingen has shifted its position several times during the same period indicating...... 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....

  18. Sea-level variation/change and thermal contribution in the Bering Sea

    Institute of Scientific and Technical Information of China (English)

    ZUO Juncheng; ZHANG Jianli; DU Ling; LI Peiliang; LI Lei

    2005-01-01

    The long-term sea-level trend in the Bering Sea is obtained by the analysis of TOPEX/Poseidon altimeter data, including the data of two tide gauges. The averaged sea-level in the Bering Sea rises at a rate of 2.47 mm/a from 1992 to 2002. The mean sea-level is falling in the most part of the Bering Sea, especially in its central basin, and it is rising in the northeastern part of the Bering Sea. During the 1998/99 change, the sea-level anomaly differences exhibit a significant sea-level anomaly fall in the deep basin of the Bering Sea,which is roughly in the same position where a prominent SST fall exists. The maximal fall of sea-level is about 10 cm in the southwestern part of the Bering Sea, and the maximal fall of about 2℃ in the SST also appeared in the same region as the sea level did.The steric sea-level change due to temperature variations is discussed. The results are compared with the TOPEX/Poseidon altimeter data at the different spatial scales. It is indicated that the seasonal amplitude of the steric height is about 35% of the observed TOPEX/Poseidon amplitude, which is much smaller than the 83% in the mid-latitudes area. The systematic difference between the TOPEX/Poseidon data with the range of about 7.5 cm and the thermal contribution with the range of about 2.5 cm is about 5 cm. This indicates that the thermal effect on the sea level is not as important as the case in the mid-latitudes area. In the Bering Sea, the phase of the steric height leads the observed sea level by about three months.

  19. 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

  20. 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.

  1. Estimating Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

    NARCIS (Netherlands)

    Fettweis, X.; Franco, B.; Tedesco, M.; van Angelen, J.H.; Lenaerts, J.T.M.; van den Broeke, M.R.; Gallee, H

    2012-01-01

    We report future projections of Surface Mass Balance (SMB) over the Greenland ice sheet (GrIS) obtained with the regional climate model MAR, forced by the outputs of three CMIP5 General Circulation Models (GCMs) when considering two different warming scenarios (RCP 4.5 and RCP 8.5). The GCMs selecte

  2. 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...

  3. 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...

  4. 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...

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

    Science.gov (United States)

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

    2015-01-01

    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.

  6. Long-term sea level change in the Malaysian seas from multi-mission altimetry data

    NARCIS (Netherlands)

    Din, A.H.; Omar, K.M.; Naeije, M.C.; Ses, S.

    2012-01-01

    The long-term sea level change during 1993 to 2008 was investigated in the Malaysian seas from satellite altimetry data of the TOPEX, JASON-1, ERS-1, ERS-2 and ENVISAT missions. Sea level data retrieval and reduction were carried out using the radar altimeter database system (RADS). In RADS data pro

  7. 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.

  8. Probabilistic projection of sea-level change along the world's coastlines

    OpenAIRE

    Perrette, M.; F. Landerer; Riva, R.; Frieler, K.; Meinshausen, M.

    2012-01-01

    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 changes can strongly deviate from the global mean due to ocean dynamics. In addition, gravitational adjustments redistribute seawater away from shrinking ice masses, an effect currently not incorporated in climate models. Here, we provide probabilistic projections of sea level changes along the world's coastlines for ...

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

    OpenAIRE

    Perrette, M.; F. Landerer; Riva, R.; Frieler, K.; Meinshausen, M.

    2013-01-01

    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 region...

  10. 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...

  11. 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...

  12. Impact of model resolution on sea-level variability characteristics at various space and time scales: insights from four DRAKKAR global simulations and the AVISO altimeter data

    Directory of Open Access Journals (Sweden)

    T. Penduff

    2009-07-01

    Full Text Available Four global ocean/sea-ice simulations driven by the same realistic 46-year daily atmospheric forcing were performed within the DRAKKAR project at 2°, 1°, ½° and ¼° resolutions. Model sea-level anomalies are collocated over the period 1993–2004 onto the AVISO SLA dataset. These five collocated SLA datasets are then filtered and quantitatively compared over various time and space scales regarding three characteristics: SLA standard deviations, spatial correlations between SLA variability maps, and temporal correlations between observed and simulated band-passed filtered local SLA timeseries. Beyond the 2°–1° transition whose benefits are quite moderate, further increases in resolution and associated changes in subgrid scale parameterizations simultaneously induce (i strong increases in SLA standard deviations, (ii strong improvements in the spatial distribution of SLA variability, and (iii slight decreases in temporal correlations between observed and simulation SLA timeseries. These 3 effects are not only clear on mesoscale (14–180 days and quasi-annual (5–18 months fluctuations, but also on the slower (interannual, large-scale variability ultimately involved in ocean-atmosphere coupled processes. Most SLA characteristics are monotonically affected by successive resolution increases, but irregularly and with a strong dependance on frequency and latitude. Benefits of enhanced resolution are maximum in the ½°–¼° transition, in the 14–180 day range, and within eddy-active mid- and high-latitude regions. They are particularly clear in the Southern Ocean where mesoscale eddies probably sustain a substantial intrinsic interannual variability.

  13. Climate-model induced differences in the 21st century global and regional glacier contributions to sea-level rise

    NARCIS (Netherlands)

    Giesen, R.H.; Oerlemans, J.

    2013-01-01

    The large uncertainty in future global glacier volume projections partly results from a substantial range in future climate conditions projected by global climate models. This study addresses the effect of global and regional differences in climate input data on the projected twenty-first century

  14. Global and Local Sea Level During the Last Interglacial: A Probabilistic Assessment

    CERN Document Server

    Kopp, Robert E; Maloof, Adam C; Oppenheimer, Michael

    2009-01-01

    The Last Interglacial (LIG) stage, with polar temperatures likely 3-5 C warmer than today, serves as a partial analogue for low-end future warming scenarios. Based upon a small set of local sea level indicators, the Intergovernmental Panel on Climate Change (IPCC) inferred that LIG global sea level (GSL) was about 4-6 m higher than today. However, because local sea levels differ from GSL, accurately reconstructing past GSL requires an integrated analysis of globally distributed data sets. Here we compile an extensive database of sea level indicators and apply a novel statistical approach that couples Gaussian process regression of sea level to Markov Chain Monte Carlo modeling of geochronological errors. Our analysis strongly supports the hypothesis that LIG GSL was higher than today, probably peaking at 6-9 m. Our results highlight the sea level hazard associated with even relatively low levels of sustained global warming.

  15. Global sea level change: Determination and interpretation

    Science.gov (United States)

    Douglas, Bruce C.

    1995-07-01

    The notion of sea level rise brings to the popular mind the specter of deep inundation of coastal regions. One pictures skyscrapers emerging from the waters like so many sleeping flamingos standing in the shallows of a lake. Of course if all of the world's ice sheets suddenly melted or collapsed, this vision would apply to New York City and its coastal counterparts. But there is a general consensus that such a calamity is not an immediate threat [Houghton et al, 1990]. The actual situation for the recent historical past and near future appears to be more benign, but with nonetheless extremely significant, even devastating impacts due to erosion and flooding of coastal areas.

  16. Glacier calving, dynamics, and sea-level rise. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Meier, M.F.; Pfeffer, W.T.; Amadei, B.

    1998-08-01

    The present-day calving flux from Greenland and Antarctica is poorly known, and this accounts for a significant portion of the uncertainty in the current mass balance of these ice sheets. Similarly, the lack of knowledge about the role of calving in glacier dynamics constitutes a major uncertainty in predicting the response of glaciers and ice sheets to changes in climate and thus sea level. Another fundamental problem has to do with incomplete knowledge of glacier areas and volumes, needed for analyses of sea-level change due to changing climate. The authors proposed to develop an improved ability to predict the future contributions of glaciers to sea level by combining work from four research areas: remote sensing observations of calving activity and iceberg flux, numerical modeling of glacier dynamics, theoretical analysis of the calving process, and numerical techniques for modeling flow with large deformations and fracture. These four areas have never been combined into a single research effort on this subject; in particular, calving dynamics have never before been included explicitly in a model of glacier dynamics. A crucial issue that they proposed to address was the general question of how calving dynamics and glacier flow dynamics interact.

  17. Stochastic Analysis Method of Sea Environment Simulated by Numerical Models

    Institute of Scientific and Technical Information of China (English)

    刘德辅; 焦桂英; 张明霞; 温书勤

    2003-01-01

    This paper proposes the stochastic analysis method of sea environment simulated by numerical models, such as wave height, current field, design sea levels and longshore sediment transport. Uncertainty and sensitivity analysis of input and output factors of numerical models, their long-term distribution and confidence intervals are described in this paper.

  18. Estimating the Greenland ice sheet surface mass balance contribution to future sea level rise using the regional atmospheric climate model MAR

    Directory of Open Access Journals (Sweden)

    X. Fettweis

    2013-03-01

    Full Text Available To estimate the sea level rise (SLR originating from changes in surface mass balance (SMB of the Greenland ice sheet (GrIS, we present 21st century climate projections obtained with the regional climate model MAR (Modèle Atmosphérique Régional, forced by output of three CMIP5 (Coupled Model Intercomparison Project Phase 5 general circulation models (GCMs. Our results indicate that in a warmer climate, mass gain from increased winter snowfall over the GrIS does not compensate mass loss through increased meltwater run-off in summer. Despite the large spread in the projected near-surface warming, all the MAR projections show similar non-linear increase of GrIS surface melt volume because no change is projected in the general atmospheric circulation over Greenland. By coarsely estimating the GrIS SMB changes from GCM output, we show that the uncertainty from the GCM-based forcing represents about half of the projected SMB changes. In 2100, the CMIP5 ensemble mean projects a GrIS SMB decrease equivalent to a mean SLR of +4 ± 2 cm and +9 ± 4 cm for the RCP (Representative Concentration Pathways 4.5 and RCP 8.5 scenarios respectively. These estimates do not consider the positive melt–elevation feedback, although sensitivity experiments using perturbed ice sheet topographies consistent with the projected SMB changes demonstrate that this is a significant feedback, and highlight the importance of coupling regional climate models to an ice sheet model. Such a coupling will allow the assessment of future response of both surface processes and ice-dynamic changes to rising temperatures, as well as their mutual feedbacks.

  19. Modelling dynamics of Jakobshavn Isbræ and its contribution to sea level rise over the past and future century

    DEFF Research Database (Denmark)

    Muresan, Ioana Stefania

    with observations of changes in glacier terminus. An initial, and most probably the first significant acceleration of JI after the end of LIA was modelled in ~1930. Overall, I found that the ocean influence in JI’s behaviour overthe last century is significant and most of the JI retreat during 1840–2014 is driven...... by the ocean parametrization and the glacier’s subsequent response, which waslargely governed by its own bed geometry. In my simulations, the retreat of the frontreduced the buttressing at the terminus and generated a dynamic response in theupstream region of JI which finally led to flow acceleration...... change is dynamic in origin). The study further indicates that the change in mass loss at JI is already triggered and that an eminent collapse of the terminus by the end of the century with retreat of up to 40 km along JI’s downward-sloping, marine-based bed is inevitable. A cooling experiment suggested...

  20. 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

  1. Is the detection of accelerated sea level rise imminent?

    Science.gov (United States)

    Fasullo, J. T.; Nerem, R. S.; Hamlington, B.

    2016-08-01

    Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time. In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era. Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This masking arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption. A consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade.

  2. Milankovitch forcing of the last interglacial sea level.

    Science.gov (United States)

    Crowley, T J; Kim, K Y

    1994-09-09

    During the last interglacial, sea level was as high as present, 4000 to 6000 years before peak Northern Hemisphere insolation receipt 126,000 years ago. The sea-level results are shown to be consistent with climate models, which simulate a 3 degrees to 4 degrees C July temperature increase from 140,000 to 130,000 years ago in high latitudes, with all Northern Hemisphere land areas being warmer than present by 130,000 years ago. The early warming occurs because obliquity peaked earlier than precession and because precession values were greater than present before peak precessional forcing occurred. These results indicate that a fuller understanding of the Milankovitch-climate connection requires consideration of fields other than just insolation forcing at 65 degrees N.

  3. Multiscale Models of Melting Arctic Sea Ice

    Science.gov (United States)

    2014-09-30

    1 Multiscale Models of Melting Arctic Sea Ice Kenneth M. Golden University of Utah, Department of Mathematics phone: (801) 581-6851...feedback has played a major role in the recent declines of the summer Arctic sea ice pack. However, understanding the evolution of melt ponds and sea...Models of Melting Arctic Sea Ice 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER

  4. A study of long-term sea level variability in the East China Sea

    Institute of Scientific and Technical Information of China (English)

    XU Ying; LIN Mingsen; ZHENG Quanan; YE Xiaomin; LI Junyi; ZHU Benlu

    2015-01-01

    From the analyses of the satellite altimeter Maps of Sea Level Anomaly (MSLA) data, tidal gauge sea level data and historical sea level data, this paper investigates the long-term sea level variability in the East China Sea (ECS). Based on the correlation analysis, we calculate the correlation coefficient between tidal gauge and the closest MSLA grid point, then generate the map of correlation coefficient of the entire ECS. The results show that the satellite altimeter MSLA data is effective to observe coastal sea level variability. An important finding is that from map of correlation coefficient we can identify the Kuroshio. The existence of Kuroshio decreases the correlation between coastal and the Pacific sea level. Kurishio likes a barrier or a wall, which blocks the effect of the Pacific and the global change. Moreover, coastal sea level in the ECS is mainly associated with local systems rather than global change. In order to calculate the long-term sea level variability trend, the empirical mode decomposition (EMD) method is applied to derive the trend on each MSLA grid point in the entire ECS. According to the 2-D distribution of the trend and rising rate, the sea level on the right side of the axis of Kuroshio rise faster than in its left side. This result supports the barrier effect of Kuroshio in the ECS. For the entire ECS, the average sea level rose 45.0 mm between 1993 and 2010, with a rising rate of (2.5±0.4) mm/a which is slower than global average. The relatively slower sea level rising rate further proves that sea level rise in the ECS has less response to global change due to its own local system effect.

  5. Sensitivity of Red Sea circulation to sea level and insolation forcing during the last interglacial

    NARCIS (Netherlands)

    Trommer, G.; Siccha, M.; Rohling, E.J.; Grant, K.; van der Meer, M.T.J.; Schouten, S.; Baranowski, U.; Kucera, M.

    2011-01-01

    This study investigates the response of Red Sea circulation to sea level and insolation changes during termination II and across the last interglacial, in comparison with termination I and the Holocene. Sediment cores from the central and northern part of the Red Sea were investigated by

  6. 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.

  7. 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

    located furthest away from the former Laurentide Ice Sheet. Rates of RSL change were highest during the early Holocene and have decreased over time due primarily to the reduction of ice equivalent meltwater input. Sea-level observations are compared to predictions from glacio-isostatic adjustment (GIA) models, and the relative influence of tectonic vertical land movements on the RSL records in each region is assessed. Background rates of late Holocene RSL change are also compared to local tide gauge records to determine excess rates of 20th century RSL rise.

  8. Drivers of sea-level change - using relative sea level records from the North and South Atlantic to fingerprint sources of mid-Holocene ice melt

    Science.gov (United States)

    Horton, B.; Khan, N.; Ashe, E.; Kopp, R. E.; Long, A. J.; Gehrels, W. R.

    2015-12-01

    Many factors give rise to relative sea-level (RSL) changes that are far from globally uniform. For example, spatially variable sea-level responses arise because of the exchange of mass between ice sheets and oceans. Gravitational, flexural, and rotational processes generate a distinct spatial pattern - or "fingerprint" - of sea-level change associated with each shrinking land ice mass. As a land ice mass shrinks, sea-level rise is greater in areas geographically distal to the ice mass than in areas proximal to it, in large part because the gravitational attraction between the ice mass and the ocean is reduced. Thus, the U.S. mid-Atlantic coastline experiences about 50% of the global average sea-level-rise due to Greenland Ice Sheet melt, but about 120% of the global average due to West Antarctic Ice Sheet melt. Separating the Greenland and Antarctic ice sheet contributions during the past 7,000 years requires analysis of sea-level changes from sites in the northern and southern hemisphere. Accordingly we present sea-level records within a hierarchical statistical modeling to: (1) quantify rates of change; (2) compare rates of change among sites, including full quantification of the uncertainty in their differences; and (3) test hypotheses about the sources of meltwater through their sea-level fingerprints. Preliminary analysis of three sites within our North and South Atlantic sea-level database indicates sea-level gradient in the rate of RSL rise during the mid Holocene between 6000 and 4000 years BP; a greater change in rate is found in Brazil than St Croix than New Jersey, consistent with an increase and then decrease in Greenland Ice Sheet mass.

  9. A modeling study of the impacts of Mississippi River diversion and sea-level rise on water quality of a deltaic estuary

    Science.gov (United States)

    Wang, Hongqing; Chen, Qin; Hu, Kelin; LaPeyre, Megan K.

    2017-01-01

    Freshwater and sediment management in estuaries affects water quality, particularly in deltaic estuaries. Furthermore, climate change-induced sea-level rise (SLR) and land subsidence also affect estuarine water quality by changing salinity, circulation, stratification, sedimentation, erosion, residence time, and other physical and ecological processes. However, little is known about how the magnitudes and spatial and temporal patterns in estuarine water quality variables will change in response to freshwater and sediment management in the context of future SLR. In this study, we applied the Delft3D model that couples hydrodynamics and water quality processes to examine the spatial and temporal variations of salinity, total suspended solids, and chlorophyll-α concentration in response to small (142 m3 s−1) and large (7080 m3 s−1) Mississippi River (MR) diversions under low (0.38 m) and high (1.44 m) relative SLR (RSLR = eustatic SLR + subsidence) scenarios in the Breton Sound Estuary, Louisiana, USA. The hydrodynamics and water quality model were calibrated and validated via field observations at multiple stations across the estuary. Model results indicate that the large MR diversion would significantly affect the magnitude and spatial and temporal patterns of the studied water quality variables across the entire estuary, whereas the small diversion tends to influence water quality only in small areas near the diversion. RSLR would also play a significant role on the spatial heterogeneity in estuary water quality by acting as an opposite force to river diversions; however, RSLR plays a greater role than the small-scale diversion on the magnitude and spatial pattern of the water quality parameters in this deltaic estuary.

  10. Towards regional projections of twenty-first century sea-level change based on IPCC SRES scenarios

    NARCIS (Netherlands)

    Slangen, A.B.A.; Katsman, C.A.; Van de Wal, R.S.W.; Vermeersen, L.L.A.; Riva, R,E.M.

    2012-01-01

    Sea-level change is often considered to be globally uniform in sea-level projections. However, local relative sea-level (RSL) change can deviate substantially from the global mean. Here, we present maps of twenty-first century local RSL change estimates based on an ensemble of coupled climate model

  11. A global observing system for monitoring and prediction of sea level change

    Science.gov (United States)

    Fu, Lee-Lueng

    science approach. The system consists of the following elements: (1) the measurement of sea level relative to the land, (2) the measurement of the main components of the ice mass contribution to sea level (i.e. surface mass balance and ice dynamics), (3) the steric contribution to sea level, (4) the mechanisms determining the geographic distribution of sea level change; and (5) the integration of these observations in advanced numerical models for hindcast and projection of sea level change. This global observing system will be discussed in the presentation.

  12. 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.

  13. River discharge contribution to sea-level rise in the Yangtze River Estuary, China

    Science.gov (United States)

    Kuang, Cuiping; Chen, Wei; Gu, Jie; Su, Tsung-Chow; Song, Hongling; Ma, Yue; Dong, Zhichao

    2017-02-01

    Sea level changes in the Yangtze River Estuary (YRE) as a result of river discharge are investigated based on the monthly averaged river discharge from 1950 to 2011 at the Datong station. Quantification of the sea level contribution is made by model computed results and the sea level rates reported by the China Sea Level Bulletin (CSLB). The coastal modeling tool, MIKE21, is used to establish a depth-averaged hydrodynamic model covering the YRE and Hangzhou Bay. The model is validated with the measured data. Multi-year monthly river discharges are statistically calculated based on the monthly river discharges at Datong station from 1950 to 2011. The four characteristic discharges (frequency of 75%, 50% and 25%, and multi-year monthly) and month-averaged river discharge from 1950 to 2011 are used to study the seasonal and long-term changes of sea level. The computed sea level at the Dajishan and Lvsi stations are used to study the multi-time scale structure of periodic variation in different time scale of river discharge series. The results reveal that (1) the sea level rises as the river discharge increases, and its amplification decreases from upstream to the offshore. (2) The sea level amplification on the south coast is greater than that on the north coast. When river discharge increases by 20,000 m3/s, the sea level will increase by 0.005-0.010 m in most of Hangzhou Bay. (3) The sea level at the Dajishan station, influenced by river discharge, increased 0.178 mm/y from 1980 to 2011. Correspondingly, the sea level rose at a rate of 2.6-3.0 mm/y during the same period. These values were provided by the CSLB. The increase in sea level (1980-2011) at the Dajishan station caused by river discharge is 6.8-8.9% of the total increase in sea level. (4) The 19-20 year dominant nodal cycle of sea level at the Dajishan and Lvsi stations is in accord with 18.6 year nodal cycle of main tidal constituents on Chinese coasts. It implies that the sea-level change period on the

  14. Tidal Level Response to Sea-Level Rise in the Yangtze Estuary

    Institute of Scientific and Technical Information of China (English)

    GONG Zheng; ZHANG Chang-kuan; WAN Li-ming; ZUO Jun-cheng

    2012-01-01

    The rise of tidal level in tidal reaches induced by sea-level rise has a large impact on flood control and water supply for the regions around the estuary.This paper focuses on the variations of tidal level response along the tidal reaches in the Yangtze Estuary,as well as the impacts of upstream discharge on tidal level response,due to the sea-level rise of the East China Sea.Based on the Topex/Poseidon altimeter data obtained during the period 1993~2005,a stochastic dynamic analysis was performed and a forecast model was run to predict the sea-level rise of the East China Sea.Two-dimensional hydrodynamic numerical models downscaling from the East China Sea to estuarine areas were implemented to analyze the rise of tidal level along the tidal reaches.In response to the sea-level rise,the tidal wave characteristics change slightly in nearshore areas outside the estuaries,involving the tidal range and the duration of flood and ebb tide.The results show that the rise of tidal level in the tidal reaches due to the sea-level rise has upstream decreasing trends.The step between the stations of Zhangjiagang and Shiyiwei divides the tidal reaches into two parts,in which the tidal level response declines slightly.The rise of tidal level is 1~2.5 mm/a in the upper part,and 4~6 mm/a in the lower part.The stations of Jiangyin and Yanglin,as an example of the upper part and the lower part respectively,are extracted to analyze the impacts of upstream discharge on tidal level response to the sea-level rise.The relation between the rise of tidal level and the upstream discharge can be fitted well with a quadratic function in the upper part.However,the relation is too complicated to be fitted in the lower part because of the tide dominance.For comparison purposes,hourly tidal level observations at the stations of Xuliujing and Yanglin during the period 1993~2009 are adopted.In order to uniform the influence of upstream discharge on tidal level for a certain day each year

  15. Seasonal cycle of sea level and currents along the coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Shankar, D.

    ON OCEAN RESEARCH IN INDIA Seasonal cycle of sea level and currents along the coast of India D. Shankar National institute of Oceanography, Dona Paula, Goa 403 004, India A framework involving long baroclinic waves, which treats the north Indian Ocean as a... to be the absence of salinity variation in these models. The large inflow of freshwater into the seas around India forces large changes in salinity, and hence, in coastal sea level. THE surface of the sea deforms continuously. Its level, measured relative...

  16. Sea level, paleogeography, and archeology on California's Northern Channel Islands

    Science.gov (United States)

    Reeder-Myers, Leslie; Erlandson, Jon M.; Muhs, Daniel R.; Rick, Torben C.

    2015-01-01

    Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80–85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution.

  17. Bowie Lecture: The Record of Sea Level Change from Satellite Measurements: What Have We Learned?

    Science.gov (United States)

    Nerem, R. S.

    2005-12-01

    Over the last decade, satellite geodetic measurements together with in situ measurements, have revolutionized our understanding of present-day sea level change. This is important because sea level change can be used as one barometer of climate variations and because of the implications sea level change has for coastal populations. With measurements from satellite altimeter missions (TOPEX/Posiedon and Jason), satellite gravity missions (GRACE), and the Global Positioning System (GPS), we are now able to start asking some important questions with regards to global sea level change and its regional variations. What has been the rate of global mean sea level change over the last dozen years? Is this rate different from the historical rate observed by the tide gauges over the last century? What are the principal causes of the observed sea level change, and are they related to anthropogenic climate variations? The record of sea level change from satellite altimetry will be reviewed, its error sources and limitations discussed, and the results placed in context with other estimates of sea level change from tide gauges, in situ measurements, and global climate models. The much shorter, but just as important, record of ocean mass variations from satellite gravity measurements will be similarly reviewed. In addition, GPS measurements of the deformation of the solid Earth due to the melting of continental ice and what they tell us about sea level change will be discussed. A sea level change budget will be presented, both for the altimetric era and the last century, containing estimates of contributions from thermal expansion, ocean mass changes (melting ice, runoff, etc.), and other contributions to sea level change. Finally, the need for continuing the satellite measurements of sea level change will be discussed in the context of future missions and the scientific gain that would result.

  18. 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

    . The model has good predictive power when calibrated on the pre-1990 period and validated against the high rates of sea level rise from the satellite altimetry. Future sea level is projected from intergovernmental panel on climate change (IPCC) temperature scenarios and past sea level from established multi......We use a physically plausible four parameter linear response equation to relate 2,000 years of global temperatures and sea level. We estimate likelihood distributions of equation parameters using Monte Carlo inversion, which then allows visualization of past and future sea level scenarios......-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...

  19. The Interannual and Decadal Variability of the Sea Level in the Japan/East Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Tianshun; LIU Yuguang; ZONG Haibo; RONG Zengrui

    2009-01-01

    Sea level observed by altimeter during the 1993-2007 period and the thermosteric sea level from 1945 through 2005 obtained by using the global ocean temperature data sets recently published are used to investigate the interannual and decadal variability of the sea level in the Japan/East Sea (JES) and its response to El Nino and Southern Oscillation (ENSO). Both the interannual variations of the sea level observed by altimeter and those of the thermosteric sea level obtained from reanalyzed data in the JES are closely related to ENSO. As a result, one important consequence is that the sea level trends are mainly caused by the thermal expansion in the JES. An 'enigma' is revealed that the correlation between the thermosteric sea level and ENSO during the PDO (Pacific Deeadal Oscillation) warm phase (post mid-1970s) is inconsistent with that during the cold phase (pre mid-1970s) in the JES. The thermosteric sea level trends and the Southern Oscillation Index (SOI) suggest a strong negative correlation during the period 1977 1998, whereas there appears a relatively weak positive correlation during the period 1945-1976 in the JES. Based on the SODA (Simple Oceanographic Data Assimilation) datasets, possible mechanisms of the interannual and deeadai variability of the sea level in the JES are discussed. Comprehensive analysis reveals that the negative anomalies of SOl correspond to the positive anomalies of the southeast wind stress, the net advective heat flux and the sea level in the JES during the PDO warm phase. During the PDO cold phase, the negative anomalies of SOl correspond to the positive anomalies of the southwest wind stress, the negative anomalies of the net advective heat flux and the sea level in the JES.

  20. A 6,700 years sea-level record based on French Polynesian coral reefs

    Science.gov (United States)

    Hallmann, Nadine; Camoin, Gilbert; Eisenhauer, Anton; Vella, Claude; Samankassou, Elias; Botella, Albéric; Milne, Glenn; Fietzke, Jan; Dussouillez, Philippe

    2015-04-01

    Sea-level change during the Mid- to Late Holocene has a similar amplitude to the sea-level rise that is likely to occur before the end of the 21st century providing a unique opportunity to study the coastal response to sea-level change and to reveal an important baseline of natural climate variability prior to the industrial revolution. Mid- to Late Holocene relative sea-level change in French Polynesia was reconstructed using coral reef records from ten islands, which represent ideal settings for accurate sea-level studies because: 1) they can be regarded as tectonically stable during the relevant period (slow subsidence), 2) they are located far from former ice sheets (far-field), 3) they are characterized by a low tidal amplitude, and 4) they cover a wide range of latitudes which produces significantly improved constraints on GIA (Glacial Isostatic Adjustment) model parameters. Absolute U/Th dating of in situ coral colonies and their accurate positioning via GPS RTK (Real Time Kinematic) measurements is crucial for an accurate reconstruction of sea-level change. We focus mainly on the analysis of coral microatolls, which are sensitive low-tide recorders, as their vertical accretion is limited by the mean low water springs level. Growth pattern analysis allows the reconstruction of low-amplitude, high-frequency sea-level changes on centennial to sub-decadal time scales. A sea-level rise of less than 1 m is recorded between 6 and 3-3.5 ka, and is followed by a gradual fall in sea level that started around 2.5 ka and persisted until the past few centuries. The reconstructed sea-level curve therefore extends the Tahiti sea-level curve [Deschamps et al., 2012, Nature, 483, 559-564], and is in good agreement with a geophysical model tuned to fit far-field deglacial records [Bassett et al., 2005, Science, 309, 925-928].

  1. Modelling chemistry over the Dead Sea: bromine and ozone chemistry

    Directory of Open Access Journals (Sweden)

    R. von Glasow

    2009-07-01

    Full Text Available Measurements of O3 and BrO concentrations over the Dead Sea indicate that Ozone Depletion Events (ODEs, widely known to happen in polar regions, are also occuring over the Dead Sea due to the very high bromine content of the Dead Sea water. However, we show that BrO and O3 levels as they are detected cannot solely be explained by high Br levels in the Dead Sea water and the release of gas phase halogen species out of sea borne aerosol particles and their conversion to reactive halogen species. It is likely that other sources for reactive halogen compounds are needed to explain the observed concentrations for BrO and O3. To explain the chemical mechanism taking place over the Dead Sea leading to BrO levels of several pmol/mol we used the one-dimensional model MISTRA which calculates microphysics, meteorology, gas and aerosol phase chemistry. We performed pseudo Lagrangian studies by letting the model column first move over the desert which surrounds the Dead Sea region and then let it move over the Dead Sea itself. To include an additional source for gas phase halogen compounds, gas exchange between the Dead Sea water and the atmosphere is treated explicitly. Model calculations indicate that this process has to be included to explain the measurements.

  2. The Paris Agreement's imprint on 2300 sea level rise

    Science.gov (United States)

    Mengel, Matthias; Nauels, Alexander; Rogelj, Joeri; Schleussner, Carl-Friedrich

    2017-04-01

    The 2015 Paris Agreement aims at reducing climate-related risks by putting a limit to global mean temperature increase. Furthermore, global greenhouse gas emissions should peak as soon as possible and reach net-zero in the second half of the 21st century under the agreement. Sea level rise is one of the major impacts of climate change and will continue for long after emissions have ceased. Here we quantify the effect of near-term and long-term emissions constraints of the Paris Agreement on climate-driven sea level rise until 2300 using a contribution-based methodology that is consistent with the IPCC AR5 sea level estimates. We study median sea level rise for scenarios stabilizing global mean temperatures between 1.5° C and 2° C above pre-industrial levels and net-zero greenhouse gas emission scenarios that lead to declining temperatures. Once global mean temperatures pass 1.5 °C, sea level rise below one meter until 2300 is out of reach for temperature stabilization scenarios. Net-zero emissions can reduce sea level rise caused by temperature overshoot only within limits. By linking sea level rise to near-term mitigation action, we find that delayed near-term mitigation action leads to increased sea level rise far beyond 2100.

  3. Sea-level change and projected future flooding along the Egyptian Mediterranean coast

    Directory of Open Access Journals (Sweden)

    Mohamed Shaltout

    2015-10-01

    The results indicate that DT can be used to study coastal and deep-water sea-level changes in the study area. The southern Levantine sub-basin sea level has recently risen by an average of 3.1 cm decade−1 and exhibits significant annual sea-level variation of −17 cm to 8 cm. The sea-level variation is significantly affected by several factors: sea-level variation west of the Gibraltar Strait, steric sea level, and sea-surface temperature. The GFDL simulations best describing the recent sea level over the study area, i.e., GFDL-CM3 and GFDL-ESM2M, are used to calculate the two-model ensemble mean (GFDL-2ENM, which indicates that Egypt's Mediterranean coast will experience substantial sea-level rise (SLR this century. The estimated uncertainty over the study area was 4–22 cm by 2100, with the emission assumptions dominating the three sources of uncertainty sources. Comparing the projected SLRs with digital elevation data indicates that Egypt's Mediterranean coast will only be safe from flooding by 2100 if effective adaptation methods are applied.

  4. Evaluating tidal marsh sustainability in the face of sea-level rise: a hybrid modeling approach applied to San Francisco Bay.

    Directory of Open Access Journals (Sweden)

    Diana Stralberg

    Full Text Available BACKGROUND: Tidal marshes will be threatened by increasing rates of sea-level rise (SLR over the next century. Managers seek guidance on whether existing and restored marshes will be resilient under a range of potential future conditions, and on prioritizing marsh restoration and conservation activities. METHODOLOGY: Building upon established models, we developed a hybrid approach that involves a mechanistic treatment of marsh accretion dynamics and incorporates spatial variation at a scale relevant for conservation and restoration decision-making. We applied this model to San Francisco Bay, using best-available elevation data and estimates of sediment supply and organic matter accumulation developed for 15 Bay subregions. Accretion models were run over 100 years for 70 combinations of starting elevation, mineral sediment, organic matter, and SLR assumptions. Results were applied spatially to evaluate eight Bay-wide climate change scenarios. PRINCIPAL FINDINGS: Model results indicated that under a high rate of SLR (1.65 m/century, short-term restoration of diked subtidal baylands to mid marsh elevations (-0.2 m MHHW could be achieved over the next century with sediment concentrations greater than 200 mg/L. However, suspended sediment concentrations greater than 300 mg/L would be required for 100-year mid marsh sustainability (i.e., no elevation loss. Organic matter accumulation had minimal impacts on this threshold. Bay-wide projections of marsh habitat area varied substantially, depending primarily on SLR and sediment assumptions. Across all scenarios, however, the model projected a shift in the mix of intertidal habitats, with a loss of high marsh and gains in low marsh and mudflats. CONCLUSIONS/SIGNIFICANCE: Results suggest a bleak prognosis for long-term natural tidal marsh sustainability under a high-SLR scenario. To minimize marsh loss, we recommend conserving adjacent uplands for marsh migration, redistributing dredged sediment to raise

  5. Estuaries May Face Increased Parasitism as Sea Levels Rise

    Science.gov (United States)

    Wendel, JoAnna

    2014-12-01

    Invertebrates in estuaries could be at a greater risk of parasitism as climate change causes sea levels to rise. A new paper published 8 December in Proceedings of the National Academy of Sciences of the United States of America (doi:10.1073/pnas.1416747111) describes how rapid sea level rise in the Holocene affected the population of parasitic flatworms called trematodes.

  6. Potentiality of foraminifera in deciphering paleo-sea levels

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    -bearing sediment layer in Goa and Lothal Dockyard at the head of the Gulf of Khambhat (Cambay) are discussed as case-studies of sea level rise. The results indicate the possibility of higher sea level between 4,300 and 6,000 years BP. Similarly, bottom sediments...

  7. Sea-level-rise impacts: Questioning inevitable migration

    Science.gov (United States)

    Kniveton, Dominic

    2017-08-01

    It is assumed that sea-level rise due to climate change will be so severe that those living near sea level will be forced to relocate. However, new research around a series of islands that have suffered subsidence due to a recent earthquake suggests that instead, island residents remain and use a range of strategies to adapt to regular flooding.

  8. Does Sea Level Change when a Floating Iceberg Melts?

    Science.gov (United States)

    Lan, Boon Leong

    2010-01-01

    On the answer page to a recent "Figuring Physics" question, the cute mouse asks another question: "Does the [sea] water level change if the iceberg melts?" The conventional answer is "no." However, in this paper I will show through a simple analysis involving Archimedes' principle that the sea level will rise. The analysis shows the wrong…

  9. Does Sea Level Change when a Floating Iceberg Melts?

    Science.gov (United States)

    Lan, Boon Leong

    2010-01-01

    On the answer page to a recent "Figuring Physics" question, the cute mouse asks another question: "Does the [sea] water level change if the iceberg melts?" The conventional answer is "no." However, in this paper I will show through a simple analysis involving Archimedes' principle that the sea level will rise. The analysis shows the wrong…

  10. On the Wind Stress - Sea Level Power Law.

    Science.gov (United States)

    1983-06-01

    The response of coastal sea level to local forcing by synpotic scale winds is usually assumed to be linear in wind stress . However, the response of...response to wind stress may allow significant improvement in the analysis of some sea-level problems. (Author)

  11. Estimation of Peak Water Level in Pearl River Estuary under the Background of Sea Level Rise

    Institute of Scientific and Technical Information of China (English)

    KONG; Lan; CHEN; Xiao-hong; ZHUANG; Cheng-bin; CHEN; Dong-wei

    2012-01-01

    [Objective] The study aimed to predict the peak water level in Pearl River Estuary under the background of sea level rise. [Method] The changing trends of peak water level at Denglongshan station and Hengmen station were analyzed firstly on the basis of regression models, and then sea level rise in Pearl River Estuary in 2050 was predicted to estimate the 1-in-50-year peak water level in the same year. [Result] Regression analyses showed that the increasing rate of peak water level over past years was 6.3 mm/a at Denglongshan station and 5.8 mm/a at Hengmen station. In addition, if sea level will rise by 20, 30 and 60 cm respectively in 2050, it was predicted that the 1-in-50-year peak water level will reach 3.04, 3.14 and 3.44 m at Denglongshan station, and 3.19, 3.29 and 3.59 m at Hengmen station separately. [Conclusion] The estimation of peak water level in Pearl River Estuary could provide theoretical references for water resources planning.

  12. 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.

  13. Coastal barrier stratigraphy for Holocene high-resolution sea-level reconstruction

    Science.gov (United States)

    Costas, Susana; Ferreira, Óscar; Plomaritis, Theocharis A.; Leorri, Eduardo

    2016-12-01

    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.

  14. 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.

  15. Bounding probabilistic sea-level projections within the framework of the possibility theory

    Science.gov (United States)

    Le Cozannet, Gonéri; Manceau, Jean-Charles; Rohmer, Jeremy

    2017-01-01

    Despite progresses in climate change science, projections of future sea-level rise remain highly uncertain, especially due to large unknowns in the melting processes affecting the ice-sheets in Greenland and Antarctica. Based on climate-models outcomes and the expertise of scientists concerned with these issues, the IPCC provided constraints to the quantiles of sea-level projections. Moreover, additional physical limits to future sea-level rise have been established, although approximately. However, many probability functions can comply with this imprecise knowledge. In this contribution, we provide a framework based on extra-probabilistic theories (namely the possibility theory) to model the uncertainties in sea-level rise projections by 2100 under the RCP 8.5 scenario. The results provide a concise representation of uncertainties in future sea-level rise and of their intrinsically imprecise nature, including a maximum bound of the total uncertainty. Today, coastal impact studies are increasingly moving away from deterministic sea-level projections, which underestimate the expectancy of damages and adaptation needs compared to probabilistic laws. However, we show that the probability functions used so-far have only explored a rather conservative subset of sea-level projections compliant with the IPCC. As a consequence, coastal impact studies relying on these probabilistic sea-level projections are expected to underestimate the possibility of large damages and adaptation needs.

  16. Sea level rise projections for northern Europe under RCP8.5

    OpenAIRE

    Grinsted, A.; Jevrejeva, S.; R. E. M. Riva; D. Dahl-Jensen

    2015-01-01

    Sea level rise poses a significant threat to coastal communities, infrastructure, and ecosystems. Sea level rise is not uniform globally but is affected by a range of regional factors. In this study, we calculate regional projections of 21st century sea level rise in northern Europe, focusing on the British Isles, the Baltic Sea, and the North Sea. The input to the regional sea level projection is a probabilistic projection of the major components of the global sea level budget. Local sea lev...

  17. Vulnerability of Turkish coasts to accelerated sea-level rise

    Science.gov (United States)

    Alpar, Bedri

    2009-06-01

    Accelerated rise in sea-level, and associated geological adjustment, may result in a high impact on shorelines. On the basis of hourly sea-level observations over a 20 year period, sea-level change along the Turkish coast has been investigated. In addition to relative sea-level rise, the high level of human activities in coastal areas puts a significant amount of stress on Turkish coastal zones, especially on coastal lowland plains. Coastal erosion and ground water salinization are the most important impacts and two case studies are discussed in this paper: the Kizilirmak river delta on the Black Sea; and the tourism center of Erdek on the Marmara Sea. Coastal retreat on the Kizilirmak river delta is mostly attributed to decreasing sediment supply to the coast. The shore barriers and the enclosed lagoons are likely to respond readily to future sea-level rise. At Erdek, the most important threat is intrusion of salt water into freshwater systems caused by a combination of accelerated sea-level rise, land reclamation and overexploitation of underground aquifers.

  18. Sea level and turbidity controls on mangrove soil surface elevation change

    Science.gov (United States)

    Lovelock, Catherine E.; Adame, Maria Fernanda; Bennion, Vicki; Hayes, Matthew; Reef, Ruth; Santini, Nadia; Cahoon, Donald R.

    2015-02-01

    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.

  19. 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.

  20. 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.

  1. Drivers of Holocene sea-level change in the Caribbean

    Science.gov (United States)

    Khan, Nicole S.; Ashe, Erica; Horton, Benjamin P.; Dutton, Andrea; Kopp, Robert E.; Brocard, Gilles; Engelhart, Simon E.; Hill, David F.; Peltier, W. R.; Vane, Christopher H.; Scatena, Fred N.

    2017-01-01

    We present a Holocene relative sea-level (RSL) database for the Caribbean region (5°N to 25°N and 55°W to 90°W) that consists of 499 sea-level index points and 238 limiting dates. The database was compiled from multiple sea-level indicators (mangrove peat, microbial mats, beach rock and acroporid and massive corals). We subdivided the database into 20 regions to investigate the influence of tectonics and glacial isostatic adjustment on RSL. We account for the local-scale processes of sediment compaction and tidal range change using the stratigraphic position (overburden thickness) of index points and paleotidal modeling, respectively. We use a spatio-temporal empirical hierarchical model to estimate RSL position and its rates of change in the Caribbean over 1-ka time slices. Because of meltwater input, the rates of RSL change were highest during the early Holocene, with a maximum of 10.9 ± 0.6 m/ka in Suriname and Guyana and minimum of 7.4 ± 0.7 m/ka in south Florida from 12 to 8 ka. Following complete deglaciation of the Laurentide Ice Sheet (LIS) by ∼7 ka, mid-to late-Holocene rates slowed to model constrains the spatial extent of the mid-Holocene highstand. RSL did not exceed the present height during the Holocene, except on the northern coast of South America, where in Suriname and Guyana, RSL attained a height higher than present by 6.6 ka (82% probability). The highstand reached a maximum elevation of +1.0 ± 1.1 m between 5.3 and 5.2 ka. Regions with a highstand were located furthest away from the former LIS, where the effects from ocean syphoning and hydro-isostasy outweigh the influence of subsidence from forebulge collapse.

  2. Spatial and temporal variability of late Holocene sea-level changes in the North Atlantic (Invited)

    Science.gov (United States)

    Kemp, A.; Kopp, R. E.; Horton, B.; Cahill, N.

    2013-12-01

    Proxy sea-level reconstructions spanning the last ~2000 years capture multiple phases of climate and sea level behavior for model calibration, provide a pre-anthropogenic background against which to compare recent trends, and characterize patterns of natural spatial and temporal variability. In the western North Atlantic basin, salt-marsh sediment is an archive for reconstructing sea level with the decimeter and multi-decadal resolution necessary to characterize subtle changes. New and existing salt-marsh reconstructions from northern Florida, North Carolina, New Jersey, Connecticut, and Massachusetts provide a dataset for investigating spatial and temporal sea-level variability during the late Holocene. The reconstructions were developed using foraminifera, plants, and bulk sediment δ13C values as sea-level proxies. The age of sediment deposition was estimated from composite chronologies of radiocarbon and chronohorizons of regional pollution and land-use change that were combined in age depth models. We used a spatio-temporal Gaussian process model to identify and characterize persistent phases of sea level behavior during the late Holocene in the western North Atlantic Ocean. The results indicate an acceleration in global mean sea level from the early 19th century through the early 20th century. The rate of sea-level rise increased significantly in the late 19th century. The timing and magnitude of this rise varied among sites even after accounting for differences in glacio-isostatic adjustment. Sea level in North Carolina rose faster than in New Jersey sea-level during the Medieval Climate Optimum, while sea level in New Jersey rose faster during the Little Ice Age. Spatially variable sea-level rise on the Atlantic coast of North America can be caused by dynamic oceanographic processes and/or melting of the Greenland Ice Sheet. Our analysis suggests that plausible levels of meltwater input from Greenland would be inadequate to explain the reconstructed pattern

  3. 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

    over this period. In the Indian Ocean and particularly the Pacific Ocean the trends in both sea level and temperature are still dominated by the large changes associated with the El Nino Southern Oscillation. In terms of contribution to the total global sea level change, the contribution of the central...

  4. 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.

    analysi s. The model p a- rameters such as atmospheric pressure field at the surface and near surface wind field during a future climate sc e- nario (2041 ? 2060) were used to identify the occurrence of lows, depressions and cyclones to determine... lows, depress ions to c y- clones. Thus, sea level pre s sure fields, at least, on a daily time scale are needed to identify the evolution of atmo s- pheric disturbances. A given disturbance is chara c terized by two parameters, namely, the maximum...

  5. Impact of sea level rise on tidal range in Chesapeake and Delaware Bays

    Science.gov (United States)

    Lee, Serena Blyth; Li, Ming; Zhang, Fan

    2017-05-01

    Coastal inundation is affected not only by rising mean sea level but also by changing tides. A numerical model is developed to investigate how sea level rise and coastline changes may impact tides in two coastal-plain estuaries, Chesapeake Bay and Delaware Bay. Despite their different tidal characteristics, the two estuaries display similar responses to the sea level rise and shoreline management scenarios. When hypothetic sea walls are erected at the present coastline to prevent low-lying land from flooding, tidal range increases, with greater amplification in the upper part of the two estuaries. When low-lying land is allowed to become permanently inundated by higher sea level, however, tidal range in both estuaries decreases. Analyses of the tidal energy budget show that the increased dissipation over the shallow water and newly inundated areas compensates for the reduced dissipation in deep water, leading to smaller tidal range. The changes in the tidal range are not proportional to the changes in the mean sea level, indicating a nonlinear tidal response to sea level rise. The ratio of tidal range change to sea level rise varies between -0.05 and 0.1 in Chesapeake Bay and between -0.2 and 0.25 in Delaware Bay. The model results suggest a potential adaptation strategy that uses inundation over low-lying areas to reduce tidal range at up-estuary locations.

  6. Impact of the 3 °C temperature rise on bacterial growth and carbon transfer towards higher trophic levels: Empirical models for the Adriatic Sea

    Science.gov (United States)

    Šolić, Mladen; Krstulović, Nada; Šantić, Danijela; Šestanović, Stefanija; Kušpilić, Grozdan; Bojanić, Natalia; Ordulj, Marin; Jozić, Slaven; Vrdoljak, Ana

    2017-09-01

    The Mediterranean Sea (including the Adriatic Sea) has been identified as a 'hotspot' for climate change, with the prediction of the increase in water temperature of 2-4 °C over the next few decades. Being mainly oligotrophic, and strongly phosphorus limited, the Adriatic Sea is characterized by the important role of the microbial food web in production and transfer of biomass and energy towards higher trophic levels. We hypothesized that predicted 3 °C temperature rise in the near future might cause an increase of bacterial production and bacterial losses to grazers, which could significantly enlarge the trophic base for metazoans. This empirical study is based on a combined 'space-for-time substitution' analysis (which is performed on 3583 data sets) and on an experimental approach (36 in situ grazing experiments performed at different temperatures). It showed that the predicted 3 °C temperature increase (which is a result of global warming) in the near future could cause a significant increase in bacterial growth at temperatures lower than 16 °C (during the colder winter-spring period, as well as in the deeper layers). The effect of temperature on bacterial growth could be additionally doubled in conditions without phosphorus limitation. Furthermore, a 3 °C increase in temperature could double the grazing on bacteria by heterotrophic nanoflagellate (HNF) and ciliate predators and it could increase the proportion of bacterial production transferred to the metazoan food web by 42%. Therefore, it is expected that global warming may further strengthen the role of the microbial food web in a carbon cycle in the Adriatic Sea.

  7. Forecasting the impact of storm waves and sea-level rise on Midway Atoll and Laysan Island within the Papahānaumokuākea Marine National Monument—a comparison of passive versus dynamic inundation models

    Science.gov (United States)

    Storlazzi, Curt D.; Berkowitz, Paul; Reynolds, Michelle H.; Logan, Joshua B.

    2013-01-01

    Two inundation events in 2011 underscored the potential for elevated water levels to damage infrastructure and affect terrestrial ecosystems on the low-lying Northwestern Hawaiian Islands in the Papahānaumokuākea Marine National Monument. The goal of this study was to compare passive "bathtub" inundation models based on geographic information systems (GIS) to those that include dynamic water levels caused by wave-induced set-up and run-up for two end-member island morphologies: Midway, a classic atoll with islands on the shallow (2-8 m) atoll rim and a deep, central lagoon; and Laysan, which is characterized by a deep (20-30 m) atoll rim and an island at the center of the atoll. Vulnerability to elevated water levels was assessed using hindcast wind and wave data to drive coupled physics-based numerical wave, current, and water-level models for the atolls. The resulting model data were then used to compute run-up elevations using a parametric run-up equation under both present conditions and future sea-level-rise scenarios. In both geomorphologies, wave heights and wavelengths adjacent to the island shorelines increased more than three times and four times, respectively, with increasing values of sea-level rise, as more deep-water wave energy could propagate over the atoll rim and larger wind-driven waves could develop on the atoll. Although these increases in water depth resulted in decreased set-up along the islands’ shorelines, the larger wave heights and longer wavelengths due to sea-level rise increased the resulting wave-induced run-up. Run-up values were spatially heterogeneous and dependent on the direction of incident wave direction, bathymetry, and island configuration. Island inundation was modeled to increase substantially when wave-driven effects were included, suggesting that inundation and impacts to infrastructure and terrestrial habitats will occur at lower values of predicted sea-level rise, and thus sooner in the 21st century, than suggested

  8. Sea-Level Rise Impacts on Hudson River Marshes

    Science.gov (United States)

    Hooks, A.; Nitsche, F. O.

    2015-12-01

    The response of tidal marshes to increasing sea-level rise is uncertain. Tidal marshes can adapt to rising sea levels through vertical accretion and inland migration. Yet tidal marshes are vulnerable to submergence if the rate of sea-level rise exceeds the rate of accretion and if inland migration is limited by natural features or development. We studied how Piermont and Iona Island Marsh, two tidal marshes on the Hudson River, New York, would be affected by sea-level rise of 0.5m, 1m, and 1.5m by 2100. This study was based on the 2011-2012 Coastal New York LiDAR survey. Using GIS we mapped sea-level rise projections accounting for accretion rates and calculated the submerged area of the marsh. Based on the Hudson River National Estuarine Research Reserve Vegetation 2005 dataset, we studied how elevation zones based on vegetation distributions would change. To evaluate the potential for inland migration, we assessed land cover around each marsh using the National Land Cover Database 2011 Land Cover dataset and examined the slope beyond the marsh boundaries. With an accretion rate of 0.29cm/year and 0.5m of sea-level rise by 2100, Piermont Marsh would be mostly unchanged. With 1.5m of sea-level rise, 86% of Piermont Marsh would be flooded. For Iona Island Marsh with an accretion rate of 0.78cm/year, sea-level rise of 0.5m by 2100 would result in a 4% expansion while 1.5m sea-level rise would cause inundation of 17% of the marsh. The results indicate that Piermont and Iona Island Marsh may be able to survive rates of sea-level rise such as 0.5m by 2100 through vertical accretion. At rates of sea-level rise like 1.5m by 2100, vertical accretion cannot match sea-level rise, submerging parts of the marshes. High elevations and steep slopes limit Piermont and Iona Island Marsh's ability to migrate inland. Understanding the impacts of sea-level rise on Piermont and Iona Island Marsh allows for long-term planning and could motivate marsh conservation programs.

  9. Climate Variabilities of Sea Level around the Korean Peninsula

    Institute of Scientific and Technical Information of China (English)

    Yong-Hoon YOUN; Im Sang OH; Young-Hyang PARK; Ki-Hyun KIM

    2004-01-01

    In order to study the climate variabilities of the sea level around the Korean Peninsula, tidal data observed at local stations in Korea were compared against those obtained using TOPEX/POSEIDON (T/P) altimetric sea level data. In the course of our study, the amount of sea level rise was estimated using the tidal data from 9 stations selected by an anomaly coherency analysis. The results indicated that the sea level has risen by 0.28 cm yr-1 around the Korean Peninsula over the past two decades. The extent of such a rise is about two times higher than that of the global increase (0.1-0.2 cm yr-1). However,because most global warming effects occurred mainly over mid- and high-latitudes, this level of change appears to be realistic. According to the spectral analysis (at a spectral window of k = 2, k is the number of subdivisions), the decadal band of sea level variability is computed at 30% of the energy. Its spectral peak is found at 12.8 years. In the interannual band, the predominant sea level variability is in the 1.4-1.9-year band, with a sharp peak at 1.6 years. A secondary peak, although marginal, has a period of 2.2years. Based on our estimates of sea level height from Topex/Poseidon, the quasi-biennial periodicity of 1.6 years is the representative interannual sea level variability in the seas adjacent to Korea. Trends vary greatly according to the geographical location, from a maximum of 1.0 cm yr-1 (the southern sector of the East Sea) to a minimum of 0.17 cm yr-1 (the northern sector of the East Sea). This is fairly consistent with the qualitative description already given with reference to the global map. As an analogue to the pattern seen in Korea, that of the Yellow Sea reveals practically the same trend as that of the adjacent seas (0.56 cm yr-1). However, in the case of TOPEX/POSEIDON (T/P) data, there is no clear evidence of a linkage between the interannual sea level variability around the Korean Peninsula and ENSO.

  10. 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

    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......Relative sea level curves contain coupled information about absolute sea level change and vertical lithospheric movement. Such curves may be constructed based on, for example tide gauge data for the most recent times and different types of geological data for ancient times. Correct account...... 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...

  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.

    stream_size 143507 stream_content_type text/plain stream_name Understanding_Sea_Level_rise_Variability_2010_Chapter_11_326.pdf.txt stream_source_info Understanding_Sea_Level_rise_Variability_2010_Chapter_11_326.pdf.txt Content.... This was compounded by the rate of local mean sea-level rise relative to the land level of the Mississippi Delta of several times the global average, as occurs naturally in all major deltas, together with anthropogenic changes to the delta wetlands. On much longer...

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

    Science.gov (United States)

    Vilibić, Ivica; Šepić, Jadranka

    2017-01-01

    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.

  13. Determination and characterization of 20th century global sea level rise

    Science.gov (United States)

    Kuo, Chung-Yen

    In this study, we provide a determination of the 20th Century (1900--2002) global sea level rise, the associated error budgets, and the quantifications of the various geophysical sources of the observed sea level rise, using data and geophysical models. We analyzed significant geographical variations of the global sea level including those caused by the steric component (heat and salinity) in the ocean, and the self-gravitational signal as a result of ice sheets melting, including the effects of glacial isostatic adjustment (GIA) since the Pleistocene. In particular, relative sea level data from long-term (longest is 150 year records) and over 600 tide gauge sites globally from PSMSL and other sources, and geocentric sea level data from multiple satellite altimetry (1985--2005) have been used to determine and characterize 20th century global sea level rise. Altimeter and selected tide gauge sea level data have been used for the 20th century sea level determination, accounting for relative biases between the altimeters, effects of sea level corresponding to oceanic thermal expansion, vertical motions affecting tide gauge measurements, self gravitations, and barotropic ocean response. This study is also characterized by the roles of the polar ocean in the global sea level study and addressing the question whether there is a detectable sea level rise acceleration during the last decade. Vertical motions have been estimated by combining geocentric sea level measurements from satellite altimetry (TOPEX/POSEIDON) and long-term relative (crust-fixed) sea level records from global tide gauges using the Gauss-Markov (GM) model with stochastic constraints. The study provided a demonstration of improved vertical motion solutions in semi-enclosed seas and lakes, including Fennoscandia and the Great Lakes region, showing excellent agreement with independent GPS observed radial velocities, or with predictions from GIA models. In general, the estimated uncertainty of the observed

  14. Sea Level Change for Norway: Past and Present Observations and Projections to 2100

    Science.gov (United States)

    Simpson, Matthew; Øie Nilsen, Jan Even; Ravndal, Oda; Breili, Kristian; Sande, Hilde; Kierulf, Halfdan; Steffen, Holger; Jansen, Eystein; Carson, Mark; Vestol, Olav

    2016-04-01

    Changes to mean sea level and/or sea level extremes (e.g., storm surges) will lead to changes in coastal impacts. These changes represent a changing exposure or risk to our society. Here we try to synthesize our understanding of past and present observed sea level changes for Norway, as well as providing sea level projections up until 2100. Our primary focus is changes to mean sea level but we also give updated return heights for each coastal municipality in Norway. We first analyse observed sea level changes from the Norwegian tide gauge network and from satellite altimetry. After the tide gauge data have been corrected for the effects of glacial isostatic adjustment, we show that 20th century sea level rise in Norwegian waters is broadly similar to the global average rise. Contributions to the observed sea level change and variability are discussed. We find that rate of sea level rise along the Norwegian coast is significantly higher for the period 1993-2014 than for the period 1960-2010. It is unclear, however, to what extent this higher rate represents natural variability rather than a sustained increase owing to global warming. Our regional sea level projections are based on findings from the Fifth Assessment Report (AR5) of the Intergovernmental Panel for Climate Change (IPCC), and the Coupled Model Intercomparison Project phase 5 (CMIP5) output. Average projected 21st century relative sea level change in Norway is -0.10-0.35 m (5 to 95% model ranges which is the likely range in AR5; P>66%) for RCP2.6, -0.05-0.45 m for RCP4.5, and 0.10-0.65 m for RCP8.5. The relative sea level projections can differ as much as 0.50 m from place to place. This pattern is governed by the vertical uplift rates. Quantifying the probability of levels above the likely range (i.e., the upper tail of the probability distribution) remains difficult because information is lacking. And of particular concern is that the ice sheet contribution might have a skewed distribution, which would

  15. Relative sea-level variability during the late Middle Pleistocene: New evidence from eastern England

    Science.gov (United States)

    Barlow, N. L. M.; Long, A. J.; Gehrels, W. R.; Saher, M. H.; Scaife, R. G.; Davies, H. J.; Penkman, K. E. H.; Bridgland, D. R.; Sparkes, A.; Smart, C. W.; Taylor, S.

    2017-10-01

    Unravelling patterns of relative sea-level change during previous interglacials enhances our understanding of ice sheet response to changing climate. Temperate-latitude estuarine environments have the potential to preserve continuous records of relative sea level from previous interglacial (warm) periods. This is important because, currently, we typically only have snapshots of sea-level highstands from low-latitude corals and raised palaeoshoreline indicators while the (continuous) deep-sea oxygen isotope record only provides indirect evidence of sea-level changes. Here, we focus on the Nar Valley in eastern England, in which is preserved evidence of a late middle-Pleistocene marine transgression more than 20 vertical metres in extent. By applying a model of coastal succession and sea-level tendencies, as used in Holocene sea-level studies, we assess the mode (abrupt versus gradual) of sea-level change recorded by the interglacial Nar Valley sequences. Compiled palaeo-stratigraphic evidence comprising foraminifera, pollen and amino acid racemization dating, suggests that the mode of sea-level change in the Nar Valley interglacial sequence was gradual, with potentially two phases of regional transgression and relative sea-level rise occurring at two separate times. The first phase occurred during the latter part of marine Oxygen Isotope Stage (MIS) 11 from ∼8 to 18 m OD; and, the second phase potentially occurred during early MIS 9 from ∼-3 to 3 m OD (with long-term tectonic uplift included in these estimates). We cannot conclusively preclude an alternative MIS 11 age for these lower sediments. The lack of indicators for rapid sea-level oscillations in the Nar Valley adds weight to an argument for steady melt of the ice sheets during both MIS 11 and 9.

  16. Sea level rise with warming above 2 degree

    Science.gov (United States)

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

    2017-04-01

    Holding the increase in the global average temperature to below 2 °C above pre-industrial levels, and pursuing efforts to limit the temperature increase to 1.5 °C, has been agreed by the representatives of the 196 parties of United Nations, as an appropriate threshold beyond which climate change risks become unacceptably high. Sea level rise is one of the most damaging aspects of warming climate for the more than 600 million people living in low-elevation coastal areas less than 10 meters above sea level. Fragile coastal ecosystems and increasing concentrations of population and economic activity in coastal areas, are reasons why future sea level rise is one of the most damaging aspects of the warming climate. Furthermore, sea level is set to continue to rise for centuries after greenhouse gas emissions concentrations are stabilised due to system inertia and feedback time scales. Impact, risk, adaptation policies and long-term decision making in coastal areas depend on regional and local sea level rise projections and local projections can differ substantially from the global one. Here we provide probabilistic sea level rise projections for the global coastline with warming above the 2 degree goal. A warming of 2°C makes global ocean rise on average by 20 cm, but more than 90% of coastal areas will experience greater rises, 40 cm along the Atlantic coast of North America and Norway, due to ocean dynamics. If warming continues above 2°C, then by 2100 sea level will rise with speeds unprecedented throughout human civilization, reaching 0.9 m (median), and 80% of the global coastline will exceed the global ocean sea level rise upper 95% confidence limit of 1.8 m. Coastal communities of rapidly expanding cities in the developing world, small island states, and vulnerable tropical coastal ecosystems will have a very limited time after mid-century to adapt to sea level rises.

  17. Sedimentary architecture of the Bohai Sea China over the last 1 Ma and implications for sea-level changes

    Science.gov (United States)

    Shi, Xuefa; Yao, Zhengquan; Liu, Qingsong; Larrasoaña, Juan Cruz; Bai, Yazhi; Liu, Yanguang; Liu, Jihua; Cao, Peng; Li, Xiaoyan; Qiao, Shuqing; Wang, Kunshan; Fang, Xisheng; Xu, Taoyu

    2016-10-01

    Sedimentary architecture dominated by transgression-regression cycles in the shallow Bohai shelf region contains information about global sea-level, climate and local tectonics. However, previous studies of transgression-regression cycles in this region at orbital timescales that extend back to the early Pleistocene are sparse, mainly because of the shortage of well-dated long cores. Although transgression-regression sedimentary cycles in the region have been interpreted in terms of local tectonics, sea-level, and climate change, the detailed structure of marine transgressions and their significance for Quaternary global sea-level variations remains to be examined. In this study, we present an integrated sedimentological, geochemical and paleontological study of a 212.4 m (∼1 Ma) core (BH08) recovered from the Bohai Sea, China, for which an astronomically-based age model is available. Correspondence between marine-terrestrial sedimentary cycles and global sea-level fluctuations suggests that stacking of marine and terrestrial sediments was driven mainly by glacio-eustatic sea-level fluctuations in a context in which tectonic subsidence was largely balanced by sediment supply over the last ∼1 Ma. We report a dominant 100-kyr cycle beginning at ∼650 ka, which reflects the worldwide influence of the mid-Pleistocene transition (MPT) in sea-level records. We find that neritic deposits after the MPT were relatively thicker than before the MPT, which indicates an important control of the MPT on sedimentary architecture through lengthening of the duration of sea-level highstands.

  18. 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

  19. 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.

  20. 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.

    in communication infrastructure will further improve our capability in coastal sea-level data collection in real time and its utilization for running predictive models as well as warning and alert purposes. The architecture of the system described herein...

  1. 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.

    infrastructure will further improve our capability in coastal sea- level data collection in real time and its utilisation for running predictive models as well as warning and alert purposes. The architecture of the system described herein, and operational since...

  2. Sea level trend and variability in the Singapore Strait

    Directory of Open Access Journals (Sweden)

    P. Tkalich

    2013-03-01

    Full Text Available Sea level in the Singapore Strait (SS exhibits response to various scale phenomena, from local to global. Longest tide gauge records in SS are analysed to derive local sea level trend and annual, inter-annual and multi-decadal sea level variability, which then are attributed to regional and global phenomena. Annual data gaps are reconstructed using functions correlating sea level variability with ENSO. At annual scale, sea level anomalies in SS are (quasi-periodic monsoon-driven, of the order of ±20 cm, the highest during northeast monsoon and the lowest during southwest monsoon. 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. At multi-decadal scale, annual measured sea levels in SS are varying with global mean sea level, rising at the rate 1.2–1.7 mm yr−1 for 1975–2009, 1.8–2.3 mm yr−1 for 1984–2009 and 1.9–4.6 mm yr−1 for 1993–2009. When SS rates are compared with the global trends (2.0, 2.4 and 2.8 mm yr−1, respectively derived from tide gauge measurements for the same periods, they are smaller in the earlier era and considerably larger in the recent one. Taking into account the first estimate of land subsidence rate, 1–1.5 mm yr−1 in Singapore, the recent trend of absolute sea level rise in SS follows regional tendency.

  3. The sea level fingerprint of recent ice mass fluxes

    NARCIS (Netherlands)

    Bamber, J.; Riva, R.E.M.

    2010-01-01

    The sea level contribution from glacial sources has been accelerating during the first decade of the 21st Century (Meier et al., 2007; Velicogna, 2009). This contribution is not distributed uniformly across the world's oceans due to both oceanographic and gravitational effects. We compute the sea le

  4. Characteristics and possible causes of sea level anomalies in the Xisha sea area

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; HAN Shuzong; FAN Wenjing; WANG Guosong; LIU Kexiu; ZHANG Zengjian

    2016-01-01

    Based on the analysis of wind, ocean currents, sea surface temperature (SST) and remote sensing satellite altimeter data, the characteristics and possible causes of sea level anomalies in the Xisha sea area are investigated. The main results are shown as follows: (1) Since 1993, the sea level in the Xisha sea area was obviously higher than normal in 1998, 2001, 2008, 2010 and 2013. Especially, the sea level in 1998 and 2010 was abnormally high, and the sea level in 2010 was 13.2 cm higher than the muti-year mean, which was the highest in the history. In 2010, the sea level in the Xisha sea area had risen 43 cm from June to August, with the strength twice the annual variation range. (2) The sea level in the Xisha sea area was not only affected by the tidal force of the celestial bodies, but also closely related to the quasi 2 a periodic oscillation of tropical western Pacific monsoon and ENSO events. (3) There was a significant negative correlation between sea level in the Xisha sea area and ENSO events. The high sea level anomaly all happened during the developing phase of La Niña. They also show significant negative correlations with Niño 4 and Niño 3.4 indices, and the lag correlation coefficients for 2 months and 3 months are–0.46 and –0.45, respectively. (4) During the early La Niña event form June to November in 2010, the anomalous wind field was cyclonic. A strong clockwise vortex was formed for the current in 25 m layer in the Xisha sea area, and the velocity of the current is close to the speed of the Kuroshio near the Luzon Strait. In normal years, there is a “cool eddy”. While in 2010, from July to August, the SST in the area was 2–3°C higher than that of the same period in the history.

  5. Sea level variations at tropical Pacific islands since 1950

    OpenAIRE

    M. Becker; Meyssignac, B.; Letetrel, C.; Llovel, W.; A. Cazenave; Delcroix, Thierry

    2012-01-01

    The western tropical Pacific is usually considered as one of the most vulnerable regions of the world under present-day and future global warming. It is often reported that some islands of the region already suffer significant sea level rise. To clarify the latter concern, in the present study we estimate sea level rise and variability since 1950 in the western tropical Pacific region (20 degrees S-15 degrees N; 120 degrees E-135 degrees W). We estimate the total rate of sea level change at s...

  6. Benchmarking and testing the “Sea Level Equation”

    DEFF Research Database (Denmark)

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

    . 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...... from the interpretation of modern satellite geodetic measurements to the projections of future sea level trends in response to climate change. All the processes accompanying GIA can be described solving the so-called Sea Level Equation (SLE), an integral equation that accounts for the interactions be...

  7. Extracting sea level residual in tidally dominated estuarine environments

    Science.gov (United States)

    Brown, Jennifer M.; Bolaños, Rodolfo; Howarth, Michael J.; Souza, Alejandro J.

    2012-07-01

    Sea level comprises a mean level, tidal elevation and a residual elevation. Knowledge of what causes maximum water levels is often key in coastal management. However, different methods to extract deviations in water level (residuals) from modelled and observed elevation can give different results. The Dee Estuary, northwest England is a macrotidal estuary that undergoes periodic stratification. It is used here to demonstrate methods to extract the residual water level in response to the following interactive processes: tidal, river-induced stratification and flow, meteorology and waves. Using modelling techniques, the interaction and contribution of different physical processes are investigated. Classical harmonic tidal analysis, model simulations and filtering techniques have been used to "de-tide" the total elevation for short-term (approximately month long) records. Each technique gives a different result highlighting the need to select the correct method for a required study. Analysis of the residual components demonstrates that all processes inducing residuals interact with the tide generating a semi-diurnal residual component. It is suggested that modelling methods enable the full effect of tidal interaction to remain in the residual, whilst harmonic tidal analysis (partly) modify and filtering methods (fully) remove this component of the residual. The analysis methods presented and their influences on the resultant residual are applicable to other study sites. However, when applied specifically to the mouth of the Dee Estuary, the external surge is found to be the main contributor to the total residual, whilst local wind and stratification effects are of secondary importance.

  8. 基于GIS的自适应三维古海面-地面演变模型研究%The study of the adaptive 3D Old Sea Level-Land Surface Change Simulation Model based on GIS

    Institute of Scientific and Technical Information of China (English)

    钟鹤翔; 谢志仁; 闾国年; 袁林旺; 信忠保

    2011-01-01

    本文设计了基于GIS的具有"自适应"功能的三维古海面-地面演变模型.该模型可以动态演绎沿海地区"沧海桑田"的变化景象,并且可以运用历史资料及专家知识,对海面-地面变化模拟结果进行检验,根据检验结果来对模型的一系列控制参数进行自动半自动的修订,然后重新进行海面-地面演变的动态模拟,直到更趋近于真实的历史演变过程,从而实现模型的"自适应"调整.与其他模型相比,该模型具有计算控制相对准确,能够方便的进行反复模拟、验证计算,模型能自动、半自动地控制调整计算参数等的特点.运用该模型对长江三角洲地区一万年来的海面-地面系统的变化进行了反演模拟,取得了较好的模拟结果.%The expression and recognition of geographical environment, the recovery and reappearance of ancient geographical environment have been the focus in some research fields such as geography, cartography, cognitive science and artificial intelligence. As well, virtual geographical environment and the expression of multidimensional spatio-temporal information have become important research directions with the development of GIS. The reconstruction of sea surface change has long been a focus of geography, and in the past years the prediction of sea surface change has also received considerable interest. The recent development of GIS provides the opportunity for the dynamical simulations of sea surface change as well as for its visualizations. It is also an important research direction in the development situation to build the model with functions of forecast, influence and countermeasure, based on the research of the sea level historical change. This model can provide an effective method for sea level change research.In this paper we present an adaptive 3D Old Sea Level-Land Surface Change Simulation Model based on GIS for the above purpose. This model can be used to simulate the old sea levelland

  9. The sea level budget along the Northwest Atlantic coast: GIA, mass changes and deep sea-shelf interaction

    Science.gov (United States)

    Frederikse, T.; Riva, R.; Simon, K.; Kleinherenbrink, M.

    2016-12-01

    Sea level along the Atlantic coast of the United States north of Cape Hatteras shows trends and accelerations above the global average. In this study we look at the individual contributors to sea level changes in this region over the period 1958-2014 and compare the sum of contributors with observations from tide gauges and GPS stations. Both observations are analyzed in a self-consistent framework that takes eustatic effects, geoid changes and solid earth deformation, resulting from both Glacial Isostatic Adjustment (GIA) and present-day mass redistribution into account. An updated data-driven model is used to constrain the GIA signal in the region, of which large parts are affected by the forebulge collapse, causing subsidence. The GIA signal explains the largest part of the observed sea level and vertical land motion trends, as well as a large fraction of the inter-station trend differences. Present-day mass redistribution caused by ice sheet and glacier melt, dam retention and groundwater depletion account for a smaller fraction of the observed trends. Altimetry and hydrographic observations and model results show that deep steric variability in the Northwest Atlantic results in a bottom pressure signal over the shelf, which explains, after removing regional meteorological effects, the vast majority of the observed decadal coastal variability and is responsible for a substantial upward trend. The sum of the individual processes explain most of the observed decadal sea level variability, as well as the observed linear trends in both sea level and vertical land motion. The trends in present-day ice mass loss and dynamic sea level do not deviate substantially from global-mean values. A significant sea level acceleration is observed, of which about half can be attributed to mass redistribution processes. The other half can be attributed to steric expansion in the Northwest Atlantic, although separating a secular acceleration from internal variability remains a

  10. Coastal sea level variability in the US West Coast Ocean Forecast System (WCOFS)

    Science.gov (United States)

    Kurapov, Alexander L.; Erofeeva, Svetlana Y.; Myers, Edward

    2017-01-01

    Sea level variability along the US West Coast is analyzed using multi-year time series records from tide gauges and a high-resolution regional ocean model, the base of the West Coast Ocean Forecast System (WCOFS). One of the metrics utilized is the frequency of occurrences when model prediction is within 0.15 m from the observed sea level, F. A target level of F = 90% is set by an operational agency. A combination of the tidal sea level from a shallow water inverse model, inverted barometer (IB) term computed using surface air pressure from a mesoscale atmospheric model, and low-pass filtered sea level from WCOFS representing the effect of coastal ocean dynamics (DYN) provides the most straightforward approach to reaching levels F>80%. The IB and DYN components each add between 5 and 15% to F. Given the importance of the DYN term bringing F closer to the operational requirement and its role as an indicator of the coastal ocean processes on scales from days to interannual, additional verification of the WCOFS subtidal sea level is provided in terms of the model-data correlation, standard deviation of the band-pass filtered (2-60 days) time series, the annual cycle amplitude, and alongshore sea level coherence in the range of 5-120-day periods. Model-data correlation in sea level increases from south to north along the US coast. The rms amplitude of model sea level variability in the 2-60-day band and its annual amplitude are weaker than observed north of 42 N, in the Pacific Northwest (PNW) coast region. The alongshore coherence amplitude and phase patterns are similar in the model and observations. Availability of the multi-year model solution allows computation and analysis of spatial maps of the coherence amplitude. For a reference location in the Southern California Bight, relatively short-period sea level motions (near 10 days) are incoherent with those north of the Santa Barbara Channel (in part, due to coastal trapped wave scattering and/or dissipation). At a

  11. Changes in extreme regional sea level under global warming

    Science.gov (United States)

    Brunnabend, S.-E.; Dijkstra, H. A.; Kliphuis, M. A.; Bal, H. E.; Seinstra, F.; van Werkhoven, B.; Maassen, J.; van Meersbergen, M.

    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 generalized extreme value theory. This model is forced with atmospheric fluxes from a coupled climate model which has been integrated under the IPCC-SRES-A1B scenario over the period 2000-2100. Changes in 10-year return time DSL extremes are very inhomogeneous over the globe and are related to changes in ocean currents and corresponding regional shifts in ocean eddy pathways. In this scenario, several regions in the North Atlantic experience an increase in mean DSL of up to 0.4 m over the period 2000-2100. DSL extremes with a 10-year return time increase up to 0.2 m with largest values in the northern and eastern Atlantic.

  12. Annotated Bibliography of Relative Sea Level Change

    Science.gov (United States)

    1991-09-01

    established between orbital geometry changes and the oxygen isotope fluctuations in the deep sea records. The insulation effects of the Milankovitch ...melt products, amplify Milankovitch (insolation) forcing of the volumentrically dominant mid-latitude ice sheets at the 23,000-year precessional...Implications for Milankovitch Theory," Science, Vol 243, pp 1275-1280. A continuous record of 6 variations in the continental hydrosphere during the middle

  13. Miocene to Present Sea Level and the Origin of Modern Rimmed Atoll Morphology

    Science.gov (United States)

    Toomey, M.; Perron, J. T.; Raymo, M. E.; Ashton, A. D.

    2014-12-01

    Rising sea-level over the next century will reshape our coastlines and make low-lying islands more vulnerable to extreme events. Atolls could potentially provide unique geologic records from periods of high sea level analogous to those we might experience over the coming centuries. However, sea-level records from atolls have been largely overlooked, in part because the processes that shape coral reef and atoll form are often complex and, in many cases, remain unexplored. Darwin's canonical model, which proposes an evolution from fringing reef to barrier reef to atoll as an ocean island ages and subsides, cannot explain the stratigraphy or morphology of many island reefs. We will present a study that combines a numerical model of reef development with existing stratigraphic records from Pacific atolls. The model, driven by sea level, simulates the evolution of atoll morphology using parameterizations of coral growth, rim derived sediment and in situ production, dissolution, and subsidence. We use it to solve for late-Miocene to present sea level by iteratively changing the ice volume and deep-ocean temperature corrections for converting deep-ocean, benthic, δ18O to sea level and finding the best-fit between the model output and corelog stratigraphy from Enewetak Atoll. We then compare lagoon depths produced by the model for different island sizes and dissolution rates (but the same subsidence and sediment production rates) to an independent dataset of real-world observations from the Marshall, Gilbert and Caroline Island chains. Our model results suggest that a period of sustained low sea level occurred during the late Miocene before rising above present moving into the Pliocene. We propose that it was atoll exposure and enhanced lagoon dissolution during the subsequent sea-level fall since the late Pliocene, ~2.7 Ma - not crustal subsidence, as Darwin's canonical model of atoll evolution presumes - that likely drove the development of modern rimmed atoll

  14. 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.

  15. 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

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

    Science.gov (United States)

    Vilibić, Ivica; Šepić, Jadranka

    2017-01-01

    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 (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. PMID:28098195

  17. Eastern Equatorial Pacific 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 eastern Pacific region...

  18. Climate Prediction Center Tahiti Sea Level Pressure (1951-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 Tahiti sea level pressures and anomalies during 1951-present. The anomalies are departures...

  19. 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...

  20. [Book review] Sea level rise: history and consequences

    Science.gov (United States)

    Grossman, Eric E.

    2004-01-01

    Review of: Sea level Rise: history and consequences. Bruce Douglas, Michael S. Kearney and Stephen P. Leatherman (eds), Sand Diego: Academic Press, 2001, 232 pp. plus CD-RIM, US$64.95, hardback. ISBN 0-12-221345-9.

  1. 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)...

  2. USGS Map service: Coastal Vulnerability to Sea-Level Rise

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The coastal vulnerability index (CVI)provides a preliminary overview, at a National scale, of the relative susceptibility of the Nation's coast to sea-level rise....

  3. Thermosteric Sea Level Rise Projections with Parametric Uncertainty

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These files contain spatial fields of simulated yearly thermosteric sea-level anomalies between 1951-2100 (referenced to year 1800) from a perturbed physics ensemble...

  4. USGS Map service: Coastal Vulnerability to Sea-Level Rise

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The coastal vulnerability index (CVI)provides a preliminary overview, at a National scale, of the relative susceptibility of the Nation's coast to sea-level rise....

  5. 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.

    Environmental Agency and Maritime Port Authority. Discussions with NUS and Deltares colleagues, Vladan BABOVIC and Herman GERRITSEN, have been most fruitful. REFERENCES Cabanes, C., Cazenzve, A., Le Provost, C., 2001. Sea level rise during past 40...

  6. 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...

  7. Regional Sea Level Variation: California Coastal Subsidence (Invited)

    Science.gov (United States)

    Blewitt, G.; Hammond, W. C.; Nerem, R.

    2013-12-01

    Satellite altimetry over the last two decades has measured variations in geocentric sea level (GSL), relative to the Earth system center of mass, providing valuable data to test models of physical oceanography and the effects of global climate change. The societal impacts of sea level change however relate to variations in local sea level (LSL), relative to the land at the coast. Therefore, assessing the impacts of sea level change requires coastal measurements of vertical land motion (VLM). Indeed, ΔLSL = ΔGSL - ΔVLM, with subsidence mapping 1:1 into LSL. Measurements of secular coastal VLM also allow tide-gauge data to test models of GSL over the last century in some locations, which cannot be provided by satellite data. Here we use GPS geodetic data within 15 km of the US west coast to infer regional, secular VLM. A total of 89 GPS stations met the criteria that time series span >4.5 yr, and do not have obvious non-linear variation, as may be caused by local instability. VLM rates for the GPS stations are derived in the secular reference frame ITRF2008, which aligns with the Earth system center of mass to ×0.5 mm/yr. We find that regional VLM has different behavior north and south of the Mendocino Triple Junction (MTJ). The California coast has a coherent regional pattern of subsidence averaging 0.5 mm/yr, with an increasing trend to the north. This trend generally matches GIA model predictions. Around San Francisco Bay, the observed coastal subsidence of 1.0 mm/yr coherently decreases moving away from the Pacific Ocean to very small subsidence on the east shores of the bay. This gradient is likely caused by San Andreas-Hayward Fault tectonics, and possibly by differential surface loading across the bay and Sacramento-San Joachim River Delta. Thus in addition to the trend in subsidence from GIA going northward along the California coast, tectonics may also play a role where the plate boundary fault system approaches the coast. In contrast, we find that VLM

  8. Sea level differences across the Gulf Stream and Kuroshio extension

    Science.gov (United States)

    Zlotnicki, Victor

    1991-01-01

    The sea level differences between the Sargasso Sea and the slope waters across the Gulf Stream region, averaged between 73 and 61 deg W, and the comparable areas across the Kuroshio extension region, averaged between 143 and 156 deg E, were estimated using the Geosat altimeter data obtained between November 1986 and December 1988. The sea-level differences between the two regions showed a strong correlation between the northwest Atlantic and Pacific, dominated by annual cycles that peak in late-September to mid-October, with about 9 cm (the Gulf Stream region) and about 6.9 cm (Kuroshio region) amplitudes.

  9. Climate Sensitivity, Sea Level, and Atmospheric CO2

    OpenAIRE

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

    2012-01-01

    Cenozoic temperature, sea level and CO2 co-variations 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 paleoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity 3 +/- 1{\\deg}C for 4 W/m2 CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, bu...

  10. Mangrove Retreat with Rising Sea-level, Bermuda

    Science.gov (United States)

    Ellison, Joanna C.

    1993-07-01

    Low island mangroves keep up with slow sea-level rise by peat accumulation. Holocene stratigraphic records show that they maintain the same pace as sea-level rise at rates up to 9 cm/100 years. Tide gauge records from Bermuda since 1932 show sea-level rise at a rate of 28 cm/100 years. The largest mangrove area (6·26 acres) at Hungry Bay has for the last 2000 years been building peat at a rate of 8·5 to 10·6 cm/100 years. Retreat of the seaward edge has caused loss of 2·24 acres of mangroves, commencing in the last few hundred years, with a second dieback between 1900 and 1947, and a third dieback in the last decade. The substrate elevation of the seaward margin of mangroves is below mean sea-level, the normal lower limit for mangroves. Present dieback shows problems of erosion indicating that the Bruun Rule of beach erosion with sea-level rise is also appropriate for mangrove swamps. Stratigraphy shows that before 4000 BP sea-level rose at a rate of 25 cm/100 years, from 4000 to 1000 years BP the rate of sea-level rise declined to 6 cm/100 years during which time mangroves established, and in the last 1000 years there was an increase to 14·3 cm/100 years, during which time the mangroves died back. This study indicates that low island mangroves will experience problems with the rates of sea-level rise predicted for the next 50 years.

  11. Potential impact of sea level rise on French islands worldwide

    Directory of Open Access Journals (Sweden)

    Celine Bellard

    2013-11-01

    Full Text Available Although sea level rise is one of the most certain consequences of global warming, yet it remains one of the least studied. Several studies strongly suggested that sea level rise will accelerate in the future with a potentially rise from 0.5 to 2 m at the end of the century. However, currently island conservation programs do not take into account the potential effects of sea level rise. Therefore, we investigated the potential consequences of sea level rise for 1,269 French islands worldwide, by assessing the total number of island that will be totally submerged for three different scenarios (1, 2 and 3 m. Under the worst scenario, up to 12% of all islands could be entirely submerged. Two regions displayed the most significant loss of island: New Caledonia and French Polynesia. Focusing on New Caledonia, we highlighted that endemic plant species that are already classified as critically endangered by the IUCN will be the most vulnerable to sea level rise. Losses of insular habitats will thus be important in the next decades for the French islands. Given that French islands covers all latitudes in the Pacific, Indian and Atlantic oceans and in the Mediterranean, our results suggested that the implications for the 180 000 islands around the world should be considerable. Therefore, decision makers are required to define island conservation priorities that will suffer of the future sea level rise.

  12. 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...... to reconstruct known data. The relationship between the reconstruction and climatic variables, such as atmospheric pressure, and climate oscillations, including the Arctic Oscillation (AO), is examined....

  13. Internet-based Modeling, Mapping, and Analysis for the Greater Everglades (IMMAGE; Version 1.0): web-based tools to assess the impact of sea level rise in south Florida

    Science.gov (United States)

    Hearn, Paul; Strong, David; Swain, Eric; Decker, Jeremy

    2013-01-01

    South Florida's Greater Everglades area is particularly vulnerable to sea level rise, due to its rich endowment of animal and plant species and its heavily populated urban areas along the coast. Rising sea levels are expected to have substantial impacts on inland flooding, the depth and extent of surge from coastal storms, the degradation of water supplies by saltwater intrusion, and the integrity of plant and animal habitats. Planners and managers responsible for mitigating these impacts require advanced tools to help them more effectively identify areas at risk. The U.S. Geological Survey's (USGS) Internet-based Modeling, Mapping, and Analysis for the Greater Everglades (IMMAGE) Web site has been developed to address these needs by providing more convenient access to projections from models that forecast the effects of sea level rise on surface water and groundwater, the extent of surge and resulting economic losses from coastal storms, and the distribution of habitats. IMMAGE not only provides an advanced geographic information system (GIS) interface to support decision making, but also includes topic-based modules that explain and illustrate key concepts for nontechnical users. The purpose of this report is to familiarize both technical and nontechnical users with the IMMAGE Web site and its various applications.

  14. Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations that 2{\\deg}C Global Warming is Dangerous

    CERN Document Server

    Hansen, James; Hearty, Paul; Ruedy, Reto; Kelley, Maxwell; Masson-Delmotte, Valerie; Russell, Gary; Tselioudis, George; Cao, Junji; Rignot, Eric; Velicogna, Isabella; Tormey, Blair; Donovan, Bailey; Kandiano, Evgeniya; von Schuckmann, Karina; Kharecha, Pushker; Legrande, Allegra N; Bauer, Michael; Lo, Kwok-Wai

    2016-01-01

    We use numerical climate simulations, paleoclimate data, and modern observations to study the effect of growing ice melt from Antarctica and Greenland. Meltwater tends to stabilize the ocean column, inducing amplifying feedbacks that increase subsurface ocean warming and ice shelf melting. Cold meltwater and induced dynamical effects cause ocean surface cooling in the Southern Ocean and North Atlantic, thus increasing Earth's energy imbalance and heat flux into most of the global ocean's surface. Southern Ocean surface cooling, while lower latitudes are warming, increases precipitation on the Southern Ocean, increasing ocean stratification, slowing deepwater formation, and increasing ice sheet mass loss. These feedbacks make ice sheets in contact with the ocean vulnerable to accelerating disintegration. We hypothesize that ice mass loss from the most vulnerable ice, sufficient to raise sea level several meters, is better approximated as exponential than by a more linear response. Doubling times of 10, 20 or 4...

  15. An Adaptive Neuro-Fuzzy Inference System for Sea Level Prediction Considering Tide-Generating Forces and Oceanic Thermal Expansion

    Directory of Open Access Journals (Sweden)

    Li-Ching Lin Hsien-Kuo Chang

    2008-01-01

    Full Text Available The paper presents an adaptive neuro fuzzy inference system for predicting sea level considering tide-generating forces and oceanic thermal expansion assuming a model of sea level dependence on sea surface temperature. The proposed model named TGFT-FN (Tide-Generating Forces considering sea surface Temperature and Fuzzy Neuro-network system is applied to predict tides at five tide gauge sites located in Taiwan and has the root mean square of error of about 7.3 - 15.0 cm. The capability of TGFT-FN model is superior in sea level prediction than the previous TGF-NN model developed by Chang and Lin (2006 that considers the tide-generating forces only. The TGFT-FN model is employed to train and predict the sea level of Hua-Lien station, and is also appropriate for the same prediction at the tide gauge sites next to Hua-Lien station.

  16. Spatial and temporal variability in the Holocene sea-level record of the South Australian coastline

    Science.gov (United States)

    Belperio, A. P.; Harvey, N.; Bourman, R. P.

    2002-06-01

    Studies of past sea levels based on radiocarbon-dated field samples suffer variously from compilation of information from disparate locations and the imprecise nature of the dated indicators. Geographic segregation and systematic elimination of poor samples from time-depth data sets leads to improved interpretation of Holocene sea-level history. An example is presented from Southern Australia, where this is achieved through selection of higher-resolution palaeoenvironmental indicators, separation of transgressive from regressive populations, and geographic regionalisation of data. In Southern Australia, fossil sea-level indicators preserved in prograding coastal plain settings include seagrass, sandflat, mangrove, samphire and chenier ridge organo-sedimentary remains. These provide sea-level time-depth data points with a variety of elevational and dating errors. Preserved organic remains at the transition from Posidonia seagrass to intertidal sandflat environment, and from sandflat to Avicennia mangrove environment provide the most precise local data for tracing sea-level change. Time-depth plots of 233 dated sea-level indicators from South Australia generate a broad sea-level envelope tracing the Southern Australian transgression from 10,000 to ca. 6000 radiocarbon years BP, followed by a more or less consistent level to the present. Finer details of sea-level behaviour are only apparent after systematic selection, separation and regionalisation of the data. The data indicate a very rapid sea-level rise in the early Holocene, at about 16 mm/year, reaching present levels at 6400 years BP. This was followed by regionally variable regression and emergence of the land of 1-3 m, a process that continues to the present. The systematic increase from 1 to 3 m in the elevation of the 6400-year BP highstand with distance away from the shelf margin is consistent with a hydro-isostatic origin for the emergence as predicted by geophysical models.

  17. Analysis of the sea levels in Kiribati A Rising Sea of Misrepresentation Sinks Kiribati

    Science.gov (United States)

    Parker, Albert

    2016-03-01

    The sea levels of Kiribati have been stable over the last few decades, as elsewhere in the world. The Australian government funded Pacific Sea Level Monitoring (PSLM) project has adjusted sea level records to produce an unrealistic rising trend. Some information has been hidden or neglected, especially from sources of different management. The measured monthly average mean sea levels suffer from subsidence or manipulation resulting in a tilting from the about 0 (zero) mm/year of nearby tide gauges to 4 (four) mm/year over the same short time window. Real environmental problems are driven by the increasing local population leading to troubles including scarcity of water, localized sinking and localised erosion.

  18. 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.

  19. 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.

  20. Quantitative constraints on the sea-level fall that terminated the Littorina Sea Stage, southern Scandinavia

    Science.gov (United States)

    Clemmensen, Lars B.; Murray, Andrew S.; Nielsen, Lars

    2012-04-01

    The island of Anholt in the Kattegat sea (southern Scandinavia) is made up largely of an extensive beach-ridge plain. As a result of post-glacial uplift, the earliest beach-ridge and swale deposits are now raised 8-9 m above present mean sea level. It appears that growth of the plain has been almost uninterrupted over the past 7500 years; here we constrain the evolution of this plain between 6300 and 1300 years ago using optically stimulated luminescence dates. The topography and internal architecture of the fossil shoreline deposits were measured on high-resolution maps and in ground-penetrating radar (GPR) reflection data with a vertical resolution of ˜0.25 m. Shoreline topography shows significant changes with time, and it appears that one of the most striking changes took place between 4300 and 3600 years ago; in the shoreline deposits corresponding to this time interval the surface drops by around 3.5 m suggesting a marked fall in relative sea-level. Assuming a constant uplift rate of 1.2 mm/yr, the corresponding drop in absolute sea-level is estimated to be around 2.6 m. This marked sea-level fall in 700 years took place at the transition from the Middle Holocene Thermal Maximum to the Late Holocene Thermal Decline or at the end of the Littorina Sea stage in the Baltic Sea region.

  1. Comparison of Several Geoid Models over the Western Mediterranean Sea

    Science.gov (United States)

    Termens, A.; Martinez-Benjamin, J. J.

    2011-07-01

    The Mediterranean Sea is a semi-enclosed true ocean. Recent Mediterranean circulation and sea level studies using various observations and ocean general circulation models show good coherence and agreement. The satellite altimetry and tide gauge observed and model predicted sea level show good coherent with correlation coefficient of 0.6. The barotropic pressure response accounts for about 66% of the Mediterranean sea level rise (1948-2001). The estimated sea level trend (1.54 ± 0.75 mm/yr) using decadal altimetry (1985-2001) after correcting the interannual/decadal signals reconstructed using tide gauge data, agrees well with the long term trend (1948-2001) estimated using tide gauges (1.43 ± 0.09 mm/yr) in the Mediterranean Sea, and is in better agreement than before with the global long-term sea level trend (1.7 - 1.8 mm/yr). Simulation studies indicate that the time-varying mass variations of Mediterranean Sea likely are sensitive to GOCE at the few mEötvös level. One of GOCE's primary high-level data products is the global gravity model with anticipated geoid accuracy of 1 cm RMS and a spatial resolution of 130 km or longer. Actually, the International Centre for Global Earth Models (ICGEM) distributes some GOCE's Global Gravity field Models (GGMs) like GO_CONS_GCF_2_DIR (Bruinsma et al, 2010), GO_CONS_GCF_2_TIM (Pail et al, 2010a), GO_CONS_GCF_2_SPW (Migliaccio et al, 2010), GOCO01S (Pail et al, 2010b). The work focuses on the comparison between these GOCE's GGMs, EGM2008 and EIGEN-51C, with sea gravity anomalies and geoid undulations provided by existing local and regional geoids - like IBERGEO (Sevilla, 2008), IGG (Corchete et al, 2005), etc. - in the Western Mediterranean Sea in order to find the GGM that best fits this area. We also try to estimate how the GOCE geoid data, provided by ESA, works on the Western Mediterranean Sea in order to prepare future geomatic issues.

  2. 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...... frequency NSL variation (i.e., every 15min) during a storm surge event at an independent tide gauge station at the Northeast of the UK (Aberdeen)....

  3. Numerical simulation of saltwater intrusion in response to sea-level rise

    Science.gov (United States)

    Langevin, C.D.; Dausman, A.M.

    2005-01-01

    A two dimensional numerical model of variable-density groundwater flow and dispersive solute transport was used to predict the extent, rate, and lag time of saltwater intrusion in response to various sea-level rise scenarios. Three simulations were performed with varying rates of sea-level rise. For the first simulation, sea-level rise was specified at a rate of 0.9 mm/yr, which is the slowest rate of sea-level rise estimated by the Intergovernmental Panel on Climate Change (IPCC). After 100 years, the 250 mg/L chloride isochlor moved inland by about 40 m, and required an additional 8 years for the system to reach equilibrium. For the next simulation, sea-level rise was specified at 4.8 mm/yr, which is the central value of the IPCC estimate. For this moderate rate of sea-level rise, the 250 mg/L isochlor moved inland by about 740 m after 100 years, and required an additional 10 years for the system to reach equilibrium. For the fastest rate of sea level rise estimated by IPCC (8.8 mm/yr), the 250 mg/L isochlor moved inland by about 1800 m after 100 years, and required more than 50 years to reach equilibrium. Copyright ASCE 2005.

  4. Regionalization of climate model results for the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Kauker, F. [Alfred-Wegener-Institut fuer Polar- und Meeresforschung, Bremerhaven (Germany); Storch, H. von [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik

    2000-07-01

    A dynamical downscaling for the North Sea is presented. The numerical model used for the study is the coupled ice-ocean model OPYC. In a hindcast of the years 1979 to 1993 it was forced with atmospheric forcing of the ECMWF reanalysis. The models capability in simulating the observed mean state and variability in the North Sea is demonstrated by the hindcast. Two time scale ranges, from weekly to seasonal and the longer-than-seasonal time scales are investigated. Shorter time scales, for storm surges, are not captured by the model formulation. The main modes of variability of sea level, sea-surface circulation, sea-surface temperature, and sea-surface salinity are described and connections to atmospheric phenomena, like the NAO, are discussed. T106 ''time-slice'' simulations with a ''2 x CO{sub 2}'' horizon are used to estimate the effects of a changing climate on the shelf sea ''North Sea''. The ''2 x CO{sub 2}'' changes in the surface forcing are accompanied by changes in the lateral oceanic boundary conditions taken from a global coupled climate model. For ''2 x CO{sub 2}'' the time mean sea level increases up to 25 cm in the German Bight in the winter, where 15 cm are due to the surface forcing and 10 cm due to thermal expansion. This change is compared to the ''natural'' variability as simulated in the ECMWF integration and found to be not outside the range spanned by it. The variability of sea level on the weekly-to-seasonal time-scales is significantly reduced in the scenario integration. The variability on the longer-than-seasonal time-scales in the control and scenario runs is much smaller then in the ECMWF integration. This is traced back to the use of ''time-slice'' experiments. Discriminating between locally forced changes and changes induced at the lateral oceanic boundaries of the model in the circulation and

  5. Potential effects of sea-level rise on coastal wetlands in southeastern Louisiana

    Science.gov (United States)

    Glick, Patty; Clough, Jonathan; Polaczyk, Amy; Couvillion, Brady R.; Nunley, Brad

    2013-01-01

    Coastal Louisiana wetlands contain about 37% of the estuarine herbaceous marshes in the conterminous United States. The long-term stability of coastal wetlands is often a function of a wetland's ability to maintain elevation equilibrium with mean sea level through processes such as primary production and sediment accretion. However, Louisiana has sustained more coastal wetland loss than all other states in the continental United States combined due to a combination of natural and anthropogenic factors, including sea-level rise. This study investigates the potential impact of current and accelerating sea-level rise rates on key coastal wetland habitats in southeastern Louisiana using the Sea Level Affecting Marshes Model (SLAMM). Model calibration was conducted using a 1956–2007 observation period and hindcasting results predicted 35% versus observed 39% total marsh loss. Multiple sea-level-rise scenarios were then simulated for the period of 2007–2100. Results indicate a range of potential wetland losses by 2100, from an additional 2,188.97 km2 (218,897 ha, 9% of the 2007 wetland area) under the lowest sea-level-rise scenario (0.34 m), to a potential loss of 5,875.27 km2 (587,527 ha, 24% of the 2007 wetland area) in the highest sea-level-rise scenario (1.9 m). Model results suggest that one area of particular concern is the potential vulnerability of the region's baldcypress-water tupelo (Taxodium distichum-Nyssa aquatica) swamp habitat, much of which is projected to become permanently flooded (affecting regeneration) under all modeled scenarios for sea-level rise. These findings will aid in the development of ecosystem management plans that support the processes and conditions that result in sustainable coastal ecosystems.

  6. 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

    WORLDWIDE APRIL 2016 REGIONAL SEA LEVEL SCENARIOS FOR COASTAL RISK MANAGEMENT: COVER PHOTOS, FROM LEFT TO RIGHT: - Overwash of the island of Roi-Namur on...J.A., S. Gill, J. Obeysekera, W. Sweet, K. Knuuti, and J. Marburger. 2016. Regional Sea Level Scenarios for Coastal Risk Management: Managing the...DEPARTMENT OF DEFENSE COASTAL SITES WORLDWIDE REGIONAL SEA LEVEL SCENARIOS FOR COASTAL RISK MANAGEMENT: 4800 Mark Center Drive, Suite 17D08 Alexandria, VA

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

    Science.gov (United States)

    Mann, Thomas; Rovere, Alessio; Schöne, Tilo; Klicpera, André; Stocchi, Paolo; Lukman, Muhammad; Westphal, Hildegard

    2016-03-01

    Knowledge on the timing and magnitude of past sea-level changes is essential to understand modern and future sea-level variability. Holocene sea-level data from literature on the west coast of Sulawesi, central Indonesia, suggest that this region experienced two relative sea-level highstands over the last 6000 years, with magnitudes exceeding two meters. However, recent datasets from the Indo-Pacific region do not support high-magnitude sea-level oscillations during the Holocene in tectonically stable far-field locations. Here we present a new, high-precision, mid-Holocene sea-level dataset from the Spermonde Shelf off southwest Sulawesi. We surveyed 21 fossil microatolls on the reef flats of two coral islands (Pulau Panambungan and Pulau Barrang Lompo) and referred their elevations to local mean sea level and to the height of living coral. Radiometrically calibrated ages from emergent fossil microatolls on Pulau Panambungan indicate a relative sea-level highstand not exceeding 0.5 m above present at ca. 5600 cal. yr BP. The highstand is followed by a relatively rapid sea-level fall towards present sea level that was reached at around 4000 cal. yr BP. Fossil microatolls from nearby Pulau Barrang Lompo show the same trend, however with a coherent negative vertical offset of about 0.8 m compared to their equivalents on Pulau Panambungan. The largely consistent gradients of both trends (~- 0.14 mm yr- 1), the consistent elevation of living microatolls in the Spermonde, and a number of instructive geomorphic features indicate a localized, post-formational and probably recent drop of the fossil microatolls on the densely populated island Pulau Barrang Lompo. The relative sea-level trend inferred from Pulau Panambungan is well within the range of geophysical predictions based on ANICE-SELEN ice sheet model, which predict a highstand that is significantly lower than those predicted by other GIA models for this area. Although a complete interpretation of the Holocene sea-level

  8. The Red Sea Modeling and Forecasting System

    KAUST Repository

    Hoteit, Ibrahim

    2015-04-01

    Despite its importance for a variety of socio-economical and political reasons and the presence of extensive coral reef gardens along its shores, the Red Sea remains one of the most under-studied large marine physical and biological systems in the global ocean. This contribution will present our efforts to build advanced modeling and forecasting capabilities for the Red Sea, which is part of the newly established Saudi ARAMCO Marine Environmental Research Center at KAUST (SAMERCK). Our Red Sea modeling system compromises both regional and nested costal MIT general circulation models (MITgcm) with resolutions varying between 8 km and 250 m to simulate the general circulation and mesoscale dynamics at various spatial scales, a 10-km resolution Weather Research Forecasting (WRF) model to simulate the atmospheric conditions, a 4-km resolution European Regional Seas Ecosystem Model (ERSEM) to simulate the Red Sea ecosystem, and a 1-km resolution WAVEWATCH-III model to simulate the wind driven surface waves conditions. We have also implemented an oil spill model, and a probabilistic dispersion and larval connectivity modeling system (CMS) based on a stochastic Lagrangian framework and incorporating biological attributes. We are using the models outputs together with available observational data to study all aspects of the Red Sea circulations. Advanced monitoring capabilities are being deployed in the Red Sea as part of the SAMERCK, comprising multiple gliders equipped with hydrographical and biological sensors, high frequency (HF) surface current/wave mapping, buoys/ moorings, etc, complementing the available satellite ocean and atmospheric observations and Automatic Weather Stations (AWS). The Red Sea models have also been equipped with advanced data assimilation capabilities. Fully parallel ensemble-based Kalman filtering (EnKF) algorithms have been implemented with the MITgcm and ERSEM for assimilating all available multivariate satellite and in-situ data sets. We

  9. Sea-level response to melting of Antarctic ice shelves on multi-centennial timescales with the fast Elementary Thermomechanical Ice Sheet model (f.ETISh v1.0)

    Science.gov (United States)

    Pattyn, Frank

    2017-08-01

    The magnitude of the Antarctic ice sheet's contribution to global sea-level rise is dominated by the potential of its marine sectors to become unstable and collapse as a response to ocean (and atmospheric) forcing. This paper presents Antarctic sea-level response to sudden atmospheric and oceanic forcings on multi-centennial timescales with the newly developed fast Elementary Thermomechanical Ice Sheet (f.ETISh) model. The f.ETISh model is a vertically integrated hybrid ice sheet-ice shelf model with vertically integrated thermomechanical coupling, making the model two-dimensional. Its marine boundary is represented by two different flux conditions, coherent with power-law basal sliding and Coulomb basal friction. The model has been compared to existing benchmarks. Modelled Antarctic ice sheet response to forcing is dominated by sub-ice shelf melt and the sensitivity is highly dependent on basal conditions at the grounding line. Coulomb friction in the grounding-line transition zone leads to significantly higher mass loss in both West and East Antarctica on centennial timescales, leading to 1.5 m sea-level rise after 500 years for a limited melt scenario of 10 m a-1 under freely floating ice shelves, up to 6 m for a 50 m a-1 scenario. The higher sensitivity is attributed to higher ice fluxes at the grounding line due to vanishing effective pressure. Removing the ice shelves altogether results in a disintegration of the West Antarctic ice sheet and (partially) marine basins in East Antarctica. After 500 years, this leads to a 5 m and a 16 m sea-level rise for the power-law basal sliding and Coulomb friction conditions at the grounding line, respectively. The latter value agrees with simulations by DeConto and Pollard (2016) over a similar period (but with different forcing and including processes of hydrofracturing and cliff failure). The chosen parametrizations make model results largely independent of spatial resolution so that f.ETISh can potentially be

  10. Long-Term Internal Variability Effects on Centennial Dynamic Sea Level Projections

    Science.gov (United States)

    Hadi Bordbar, Mohammad; Martin, Thomas; Park, Wonsun; Latif, Mojib

    2015-04-01

    The Earth's surface is warming in response to anthropogenic emissions of greenhouse gases, especially carbon dioxide (CO2). Sea level rise is one of the most pressing aspects of global warming with far-reaching consequences for coastal societies. However, sea level rise did and will strongly vary from coast to coast. Here we investigate the long-term internal variability effects on centennial projections of dynamic sea level (DSL), the local departure from the globally averaged sea level. A large ensemble of global warming integrations was conducted with a climate model, where each ensemble member was forced by identical CO2-increase but started from different atmospheric and oceanic initial conditions taken from an unforced millennial control run. In large parts of the mid- and high latitudes, the ensemble spread of the projected centennial DSL trends is of the same order of magnitude as the globally averaged steric sea level rise, suggesting internal variability cannot be ignored when assessing 21st century DSL changes. This conclusion is also supported by analyzing projections with other climate models. The ensemble spread is strongly reduced in the mid- to high latitudes if only the atmospheric initial conditions are perturbed; suggesting uncertainty in the projected centennial DSL trends there is largely due to the lack of ocean information. Thus climate model projections of regional sea level would benefit from ocean initialization.

  11. Closing the sea level budget on a regional scale: Trends and variability on the Northwestern European continental shelf

    Science.gov (United States)

    Frederikse, Thomas; Riva, Riccardo; Kleinherenbrink, Marcel; Wada, Yoshihide; Broeke, Michiel; Marzeion, Ben

    2016-10-01

    Long-term trends and decadal variability of sea level in the North Sea and along the Norwegian coast have been studied over the period 1958-2014. We model the spatially nonuniform sea level and solid earth response to large-scale ice melt and terrestrial water storage changes. GPS observations, corrected for the solid earth deformation, are used to estimate vertical land motion. We find a clear correlation between sea level in the North Sea and along the Norwegian coast and open ocean steric variability in the Bay of Biscay and west of Portugal, which is consistent with the presence of wind-driven coastally trapped waves. The observed nodal cycle is consistent with tidal equilibrium. We are able to explain the observed sea level trend over the period 1958-2014 well within the standard error of the sum of all contributing processes, as well as the large majority of the observed decadal sea level variability.

  12. Closing the sea level budget on a regional scale: Trends and variability on the Northwestern European continental shelf.

    Science.gov (United States)

    Frederikse, Thomas; Riva, Riccardo; Kleinherenbrink, Marcel; Wada, Yoshihide; van den Broeke, Michiel; Marzeion, Ben

    2016-10-28

    Long-term trends and decadal variability of sea level in the North Sea and along the Norwegian coast have been studied over the period 1958-2014. We model the spatially nonuniform sea level and solid earth response to large-scale ice melt and terrestrial water storage changes. GPS observations, corrected for the solid earth deformation, are used to estimate vertical land motion. We find a clear correlation between sea level in the North Sea and along the Norwegian coast and open ocean steric variability in the Bay of Biscay and west of Portugal, which is consistent with the presence of wind-driven coastally trapped waves. The observed nodal cycle is consistent with tidal equilibrium. We are able to explain the observed sea level trend over the period 1958-2014 well within the standard error of the sum of all contributing processes, as well as the large majority of the observed decadal sea level variability.

  13. Glaciers dominate eustatic sea-level rise in the 21st century

    Science.gov (United States)

    Meier, Mark Frederick; Dyurgerov, M.B.; Rick, Ursula K.; Pfeffer, William Tad; Anderson, Suzanne P.; Glazovsky, Andrey F.

    2007-01-01

    Ice loss to the sea currently accounts for virtually all of the sea-level rise that is not attributable to ocean warming, and about 60% of the ice loss is from glaciers and ice caps rather than from the two ice sheets. The contribution of these smaller glaciers has accelerated over the past decade, in part due to marked thinning and retreat of marine-terminating glaciers associated with a dynamic instability that is generally not considered in mass-balance and climate modeling. This acceleration of glacier melt may cause 0.1 to 0.25 meter of additional sea-level rise by 2100.

  14. 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.

  15. 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.

  16. 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.

  17. Numerical experimentation of a diagnostic model of 3-D circulation in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Shaji, C.; Bahulayan, N.; Dube, S.K.; Rao, A.D.

    Climatic circulation in the upper levels of the Arabian Sea and western equatorial Indian Ocean are computed using a 3-dimensional, 33 level diagnostic circulation model. A steady state solution is obtained within 30 days of model integration. Model...

  18. 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.

  19. 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

    2011-12-01

    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 which consists of five main sequences stacked during the sea level lowering phases of the last five glacial-interglacial 100-kyr cycles. The high sensitivity to sea level oscillations of the grain-size record along the borehole, favoured by the large width of the Gulf of Lion continental shelf, demonstrates that sea level driven changes in accommodation space over the shelf are able to cyclically modify the depositional mode of the entire margin. PRGL1-4 data also illustrate the imprint of sea level oscillations at millennial 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 ever for a one-to-one coupling of millennial-scale sea level oscillations associated with each Dansgaard-Oeschger cycle.

  20. Improved sea level record over the satellite altimetry era (1993-2010) from the Climate Change Initiative project

    DEFF Research Database (Denmark)

    Ablain, M.; Cazenave, A.; Larnicol, G.

    2015-01-01

    Sea level is one of the 50 Essential Climate Variables (ECVs) listed by the Global Climate Observing System (GCOS) in climate change monitoring. In the past two decades, sea level has been routinely measured from space using satellite altimetry techniques. In order to address a number of importan...... present preliminary independent validations of the SL_cci products, based on tide gauges comparison and a sea level budget closure approach, as well as comparisons with ocean reanalyses and climate model outputs....

  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. 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

  3. Sea Level Rise Scenarios and Predicted Impacts on New Hampshire's Hampton-Seabrook Estuary

    Science.gov (United States)

    Haile, R.; Hale, S. R.; Rock, B. N.

    2008-12-01

    According to the Intergovernmental Panel on Climate Change, Environmental Protection Agency, and the Union of Concerned Scientist, coastal areas could experience a rise in sea level from 0.3m (conservative) to 6m (extreme). Due in part to global warming, over the last 100 years mid-Atlantic and Gulf Coast sea level has risen approximately 0.1m more than the average global rise. GIS models illustrating future sea level rise (SLR) projections were generated to assess the potential impact on beaches and estuaries of Hampton and Seabrook, New Hampshire (NH). Limited, but important, tidal wetlands are particularly at risk from rising sea levels. A raster unsupervised landcover classification and a Digital Elevation Model of the southeastern NH coastal region were overlain in ARC/GIS v. 9.0. Sea level rise predictions greater than 1.2m will result in the inundation of greater than 50 percent of the emergent area of the Hampton/Seabrook estuary and urban development fringing the estuary will be prone to greater flooding from storm surges and high tides. An approximate 6m rise in sea level will inundate greater than 95 percent of the Hampton-Seabrook tidal marsh and greater than 95 percent of New Hampshire's existing sand dunes.

  4. Substantial contribution to sea-level rise during the last interglacial from the Greenland ice sheet

    Science.gov (United States)

    Cuffey; Marshall

    2000-04-06

    During the last interglacial period (the Eemian), global sea level was at least three metres, and probably more than five metres, higher than at present. Complete melting of either the West Antarctic ice sheet or the Greenland ice sheet would today raise sea levels by 6-7 metres. But the high sea levels during the last interglacial period have been proposed to result mainly from disintegration of the West Antarctic ice sheet, with model studies attributing only 1-2 m of sea-level rise to meltwater from Greenland. This result was considered consistent with ice core evidence, although earlier work had suggested a much reduced Greenland ice sheet during the last interglacial period. Here we reconsider the Eemian evolution of the Greenland ice sheet by combining numerical modelling with insights obtained from recent central Greenland ice-core analyses. Our results suggest that the Greenland ice sheet was considerably smaller and steeper during the Eemian, and plausibly contributed 4-5.5 m to the sea-level highstand during that period. We conclude that the high sea level during the last interglacial period most probably included a large contribution from Greenland meltwater and therefore should not be interpreted as evidence for a significant reduction of the West Antarctic ice sheet.

  5. Impact of sea level rise in coastal systems - Ria de Aveiro case study

    Science.gov (United States)

    Picado, A.; Mendes, R.; Vaz, N.; Dias, J. M.

    2012-04-01

    The mean sea level rising is an important consequence of climate change because of its impact on society and coastal ecosystems. Tide gauge information evidences that global mean sea level has increased in the 20th century, and it is expected that its rise will continue during the 21th century. However, the sea levels are not changing uniformly around the world, as both tide gauge and satellite data confirm. Sea level rise can have a wide variety of impacts on worldwide coastal areas, causing flooding, land loss, the salinization of groundwater and the destruction of built property and infrastructures. In Portugal, the region's most affected by the sea level rise are probably the Aveiro and Formosa coastal lagoons as well as the Tagus and Sado estuaries. A good understanding of the sea level rise influence in the estuarine tidal dynamics is crucial to mitigate these problems. However, the response of each coastal region to sea level rise depends on the physical features of the coastal system, and therefore their effects should be locally assessed. Thus, this work aims to investigate the potential impacts of the mean sea level rise in coastal regions, analysing the particular case of Ria de Aveiro, which is in risk of flooding. To assess these changes the numerical model Mohid was implemented in Ria de Aveiro. Mohid is a finite volume model, designed for coastal and estuarine shallow water applications. Although Mohid is a 3D baroclinic model, it was used herein in baratropic mode with a single vertical layer, considering that due to its shallow depths, Ria de Aveiro circulation can be simulated with a depth integrated model. The model was used initially to characterize the lagoons hydrodynamic under the actual sea level, through the determination of the amplitude and phase of the main tidal constituents, maximum levels and velocities, tidal asymmetry, as well as the tidal prism in the main sections of the lagoon. After, a realistic regional sea level rise scenario

  6. Evidence for long-term memory in sea level

    Science.gov (United States)

    Dangendorf, Sönke; Rybski, Diego; Mudersbach, Christoph; Müller, Alfred; Kaufmann, Edgar; Zorita, Eduardo; Jensen, Jürgen

    2014-08-01

    Detection and attribution of anthropogenic climate change signals in sea level rise (SLR) has experienced considerable attention during the last decades. Here we provide evidence that superimposed on any possible anthropogenic trend there is a significant amount of natural decadal and multidecadal variability. Using a set of 60 centennial tide gauge records and an ocean reanalysis, we find that sea levels exhibit long-term correlations on time scales up to several decades that are independent of any systematic rise. A large fraction of this long-term variability is related to the steric component of sea level, but we also find long-term correlations in current estimates of mass loss from glaciers and ice caps. These findings suggest that (i) recent attempts to detect a significant acceleration in regional SLR might underestimate the impact of natural variability and (ii) any future regional SLR threshold might be exceeded earlier/later than from anthropogenic change alone.

  7. A new perspective on global mean sea level (GMSL) acceleration

    Science.gov (United States)

    Watson, Phil J.

    2016-06-01

    The vast body of contemporary climate change science is largely underpinned by the premise of a measured acceleration from anthropogenic forcings evident in key climate change proxies -- greenhouse gas emissions, temperature, and mean sea level. By virtue, over recent years, the issue of whether or not there is a measurable acceleration in global mean sea level has resulted in fierce, widespread professional, social, and political debate. Attempts to measure acceleration in global mean sea level (GMSL) have often used comparatively crude analysis techniques providing little temporal instruction on these key questions. This work proposes improved techniques to measure real-time velocity and acceleration based on five GMSL reconstructions spanning the time frame from 1807 to 2014 with substantially improved temporal resolution. While this analysis highlights key differences between the respective reconstructions, there is now more robust, convincing evidence of recent acceleration in the trend of GMSL.

  8. Investigation of sea level trends and the effect of the north atlantic oscillation (NAO) on the black sea and the eastern mediterranean sea

    Science.gov (United States)

    Ozgenc Aksoy, Aysegul

    2017-07-01

    The North Atlantic Oscillation (NAO) has significant effects on sea levels, weather, and climate. In this study, the sea level trends and the effects of the North Atlantic Oscillation Indices (NAOI) on annual mean sea level data were assessed for the Black Sea and the Eastern Mediterranean Sea. The trends of sea level and NAOI were determined using Mann-Kendall dimensionless z statistics. Generally, upward sea level trends were detected for the Black Sea and the Eastern Mediterranean Sea. In the Black Sea, significant and continuous upward trends were detected after the year 1950. Weaker trends were detected for the Eastern part of the Mediterranean Sea. Sea level trends were correlated with trends in NAO indices; negative correlations were detected for the Black Sea, whereas positive correlations were found for the Eastern Mediterranean Sea. Paired t tests were performed to determine the turning points for all sea level data sets. The value of t was positive for all data sets, which means that the mean value of the data set before the turning point was smaller than the mean value of the data set after the turning point.

  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. Interannual sea level variability in the Eastern Indian Ocean and Southern South China Sea

    Science.gov (United States)

    Mohan, S. S.; Vethamony, P.

    2016-12-01