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Sample records for eustatic sea level

  1. Eustatic sea level fluctuations induced by polar wander

    NASA Technical Reports Server (NTRS)

    Sabadini, Roberto; Doglioni, Carlo; Yuen, David A.

    1990-01-01

    It is shown here that polar wander of a viscoelastic, stratified earth can induce global sea level fluctuations comparable to the short-term component in eustatic sea-level curves. The sign of these fluctuations, which are very sensitive to the rheological stratification, depends on the geographical location of the observation point; rises and falls in sea level can thus be coeval in different parts of the world. This finding is a distinct contrast to the main assumption underlying the reconstruction of eustatic curves, namely that global sea-level events produce the same depositional sequence everywhere. It is proposed that polar wander should be added to the list of geophysical mechanisms that can control the third-order cycles in sea level.

  2. Synrift sedimentation in the Gulf of Suez rift controlled by eustatic sea level variations

    SciTech Connect

    Perry, S.K.; Schamel, S.

    1985-01-01

    Laterally persistent stratigraphic variations in the southern Gulf of Suez rift indicate that eustatic variations in sea level predominate over local tectonic effects in controlling Neogene basin-fill sedimentation. Low sea level allows extensive erosion of tilt-block crests and rift shoulders, sending clastic aprons into the intervening subbasins and allowing evaporite deposition. High sea level minimizes clastic input, allowing marls and shales to build up off structure and reefs to form on and around tilt blocks. Thus variations in sediment character indicate relative sea level. Early rifting events in the upper Oligocene are marked by deposition of continental red beds. Overlying lowest Miocene clastics and evaporites are cut by a lower Burdigalian unconformity, indicating a minor transgression in the Aquitanian. Above a disconformity, laterally varying clastics and evaporites suggest regression followed by intermittent shallow-water conditions. A higher unconformity is overlain by thick cyclic evaporites representing periodic flooding and drying of the rift, a result of sea level remaining close to the height of the Suez sill to the north. A major Messinian unconformity cuts the section, indicating major regression, and is overlain by largely clastic sediments of both continental and marine affinities, showing rapid sea level fluctuations. Regional synrift sedimentation has been controlled more by eustatic sea level change, modified by the Suez sill to the north, than by tectonic movements within the rift.

  3. Tertiary delta 18O record and glacio-eustatic sea-level fluctuations.

    USGS Publications Warehouse

    Matthews, R.K.; Poore, R.Z.

    1980-01-01

    Previous interpretation of the Tertiary delta 18O record of planktic and benthic foraminifers has emphasized comparison to the modern ocean, assumed an ice-free world prior to middle Miocene time, and thereby calculated surprisingly cool temperatures for the tropical sea surface. We propose an alternative interpretation, which compares Tertiary data to average late Pleistocene, assumes constant tropical sea-surface temperature, and thereby estimates global ice volume. This approach suggests that Earth has had a significant ice budget (and therefore glacio-eustatic sea-level fluctuations) at least since Eocene and perhaps even throughout much of Cretaceous time. -Authors

  4. New constraints on late Holocene eustatic sea-level changes from Mahé, Seychelles

    NASA Astrophysics Data System (ADS)

    Woodroffe, Sarah A.; Long, Antony J.; Milne, Glenn A.; Bryant, Charlotte L.; Thomas, Alexander L.

    2015-05-01

    This study provides new estimates of globally integrated ice sheet melt during the late Holocene (since 4 ka BP) from Seychelles in the western Indian Ocean, a tectonically stable, far field location where the necessary Glacial-Isostatic Adjustment (GIA) correction is small and is relatively insensitive to predictions using different Earth viscosity profiles. We compare sea level data from Seychelles to estimates of eustasy from two GIA models, ICE-5G and EUST3, which represent end-members in the quantity of global melt during the late Holocene. We use data from a range of coastal environments including fringing reef, present day beaches, fossil plateau and mangrove deposits on the largest island of the Seychelles archipelago, Mahé to reconstruct relative sea-level changes. Our data suggest that extensive coastal deposits of carbonate-rich sands that fringe the west coast formed in the last 2 ka and the horizontal nature of their surface topography suggests RSL stability during this period. Mangrove sediments preserved behind these deposits and in river mouths date to c. 2 ka and indicate that RSL was between -2 m and present during this interval. Correcting the reconstructed sea level data using a suite of optimal GIA models based on the two ice models mentioned above and a large number (c. 350) of Earth viscosity models gives a result that is consistent with the sedimentological constraints. When uncertainties in both model results and data are considered, it is possible to rule out eustatic sea levels below c. 2 m and more than a few decimetres above present during the past two millennia. This uncertainty is dominated by error in the reconstructions rather than the model predictions. We note, however, that our estimates of eustasy are more compatible with the EUST3 model compared to the ICE-5G model during the late Holocene (2-1 ka BP). Our evidence from Seychelles shows that the timing of when eustatic sea level first rose close to present is between the

  5. Mid-Cretaceous Eustatic sea level fall: magnitude and timing in Gulf of Mexico

    SciTech Connect

    Vierbuchen, R.C.; Oestmann, M.A.; Greenlee, S.M.

    1987-05-01

    The magnitude and timing of a mid-Cretaceous sea level fall have been documented on the margins of the Gulf of Mexico in east Texas. Analysis of seismic, log, and paleontologic data from east Texas demonstrates that a fall of 60 to 100 m occurred at the end of Washita (mid-Cenomanian) time. This sea level fall has been identified elsewhere on the shelves of the Gulf of Mexico and is proposed to have caused the mid-Cretaceous unconformity of the deep sea and the termination of Washita carbonate deposition. They conclude that this sea level fall is of regional significance and eustatic origin. The magnitude and timing of the fall agree with those postulated by Vail and others, and Haq and others, who recognized a major sea level fall in mid-Cenomanian time. The magnitude of sea level fall is estimated from the difference in elevation between carbonate buildups on the Buda margin, which accumulated at or near sea level, and fluvial deposits in the lower Woodbine, which immediately overlie Buda carbonates and have been drilled up to 20 km basinward of the shelf margin. After constructing a datum along the preexisting Buda shelf, they measure the thickness of sediment from this datum to the onlapping fluvial, lower Woodbine siliciclastics. This measurement is then corrected for compaction, isostatic subsidence due to sediment loading, and thermotectonic subsidence. The result, 60 m, is considered a minimum estimate. A similar measurement to the lowest seismically identified coastal onlap in the lower Woodbine yields an estimate of 100 m.

  6. Ferrelo fan, California: Depositional system influenced by Eustatic sea level changes

    USGS Publications Warehouse

    Howell, D.G.; Vedder, J.G.

    1984-01-01

    Remnants of an Eocene fan system are preserved onshore at San Diego and in the central part of the southern California borderland. Even though faults and erosion have truncated its margins, geophysical data and exploratory wells indicate that remaining parts of the fan extend beneath an offshore area nearly 400-km long and 40- to 100-km wide. Environments representing fluvial, fan-delta, shelf-channel, overlapping inner- to outer-fan, and basin-plain facies are recognized or inferred. Three progradational cycles onshore and two distinct pulses of sand accumulation offshore are attributable to eustatic low sea-level stands rather than to tectonic uplift or shifts in depositional patterns. ?? 1984 Springer-Verlag New York Inc.

  7. High eustatic sea level during the middle Pliocene: Evidence from the southeastern U. S. Atlantic Coastal Plain

    SciTech Connect

    Dowsett, H.J.; Cronin, T.M. )

    1990-05-01

    The middle Pliocene, {approximately}3.5-2.5 Ma, was a period of global warmth preceding the growth of major Northern Hemisphere ice sheets. The authors report on eustatic sea level for the middle Pliocene based on microspaleontologic study of marine deposits of the Duplin Formation of South Carolina and North Carolina. The Duplin was deposited during a middle Pliocene marine transgression that formed the Orangeburg scarp, a prominent wave-cut geomorphic paleoshoreline of the southeastern U.S. Atlantic Coastal Plain. They concluded that (1) the scarp in South Carolina was formed mostly during the middle Pliocene (3.5-3.0 Ma), (2) eustatic sea level was about 35 {plus minus} 18 m higher than modern sea level (the scarp has been uplifted about 50-65 m since the middle Pliocene), and (3) ocean-water temperatures along eastern North America were warmer when the scarp was formed that they are at present.

  8. The high tide of the warm Pliocene: Implications of ~20 m Peak Eustatic Sea-Levels for Antarctic Deglaciation

    NASA Astrophysics Data System (ADS)

    Miller, K. G.; Browning, J. V.; Kulpecz, A. A.; Kominz, M. A.; Naish, T.; Rosenthal, Y.; Peltier, W. R.; Sosdian, S. M.; Wright, J. D.

    2010-12-01

    The eustatic peak of the Pliocene (ca. 3 Ma) allows evaluation of sea-level response to conditions warmer than present and with atmospheric carbon dioxide levels similar to the early 21st century. We provide new eustatic estimates for the Pliocene from backstripping shallow-marine, siliciclastic sections in Virginia, U.S.A., and New Zealand, accounting for the effects of compaction, Airy loading, and thermal subsidence. We compare our backstripped eustatic estimates with previously published estimates from a carbonate atoll (Enewetak), deep sea benthic foraminiferal oxygen isotopes, Mg-Ca, and uplifted marine terraces in the Carolinas and Alaska and conclude that the peak was 19±5 m, significantly lower than previously published estimates of 30-40 m derived from uplifted terraces. The 19-m peak implies not only the loss of the total equivalent of Greenland and West Antarctic ice sheets, but suggests volume loss of the East Antarctic Ice Sheet (EAIS) of ~4 m of sea-level equivalent. Our estimates provide helps resolve the long-standing controversy of the stability of the EAIS during the warmer-than-present Pliocene climatic optimum. The sea-level fall at MIC 100 (ca. 2.7 Ma) associated with the growth of large northern hemisphere ice sheets was remarkably large (~100 m) and may have cause a glacial isotostatic adjustment the resulted in uplift of the otherwise tectonically stable New Jersey coastal plain. Despite uncertainties in pre-ice core CO2 and global temperature measurements, the Pliocene provides a critical sea level-atmospheric CO2 calibration point for climates significantly warmer than the last major interglacial, MIC 5e.

  9. Effect of eustatic sea-level changes on saltwater-freshwater relations in the Northern Atlantic Coastal Plain

    USGS Publications Warehouse

    Meisler, Harold; Leahy, P. Patrick; Knobel, LeRoy L.

    1984-01-01

    A finite-difference computer model was used to analyze the effect of eustatic sea-level changes on the development of the transition zone between fresh ground water and underlying saltwater in the northern Atlantic Coastal Plain. The model simulates, in cross section, the sedimentary wedge from the Delaware River estuary in New Jersey to the Continental Slope. Simulated steady-state freshwater flow is separated from static saltwater by a sharp interface. The model was used to test the sensitivity of the simulated interface position to anisotropy as well as to sea-level elevation. Increasing anisotropy causes the interface to be shallower and extend farther offshore. Lowering sea level causes the interface to be deeper and to extend farther offshore. Simulations using hydraulic conductivities based on available data suggest that the transition zone is not in equilibrium with present sea level. The position of the transition zone probably reflects a long-term average sea level of between 50 and 100 ft below present sea level. The cyclic movement of salty ground water in response to sea-level fluctuations during the Quaternary and Late Tertiary caused the saltwater to mix with freshwater, thus producing a broad transition zone. The freshwater is predominantly sodium bicarbonate in character. The saltwater, from New Jersey to Virginia, probably is a sodium calcium chloride brine. In North Carolina, it is primarily seawater.

  10. Glaciers dominate eustatic sea-level rise in the 21st century.

    PubMed

    Meier, Mark F; Dyurgerov, Mark B; Rick, Ursula K; O'neel, Shad; Pfeffer, W Tad; Anderson, Robert S; Anderson, Suzanne P; Glazovsky, Andrey F

    2007-08-24

    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.

  11. Glaciers dominate eustatic sea-level rise in the 21st century

    USGS Publications Warehouse

    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.

  12. Foraminifera in elevated Bermudian caves provide further evidence for +21 m eustatic sea level during Marine Isotope Stage 11

    NASA Astrophysics Data System (ADS)

    van Hengstum, Peter J.; Scott, David B.; Javaux, Emmanuelle J.

    2009-09-01

    Two hypotheses have been proposed to explain the origin of marine isotope stage (MIS) 11 deposits in small Bermudian caves at +21 m above modern sea level: (1) a +21 m MIS 11 eustatic sea-level highstand, and (2) a MIS 11 mega-tsunami event. Importantly, the foraminifera reported in these caves have yet to be critically evaluated within a framework of coastal cave environments. After statistically comparing foraminifera in modern Bermudian littoral caves and the MIS 11 Calonectris Pocket A (+21 m cave) to the largest available database of Bermudian coastal foraminifera, the assemblages found in modern littoral caves - and Calonectris Pocket A - cannot be statistically differentiated from lagoons. This observation is expected considering littoral caves are simply sheltered extensions of a lagoon environment in the littoral zone, where typical coastal processes (waves, storms) homogenize and rework lagoonal, reefal, and occasional planktic taxa. Fossil protoconchs of the Bermudian cave stygobite Caecum caverna were also associated with the foraminifera. These results indicate that the MIS 11 Bermudian caves are fossil littoral caves (breached flank margin caves), where the total MIS 11 microfossil assemblage is preserving a signature of coeval sea level at +21 m. Brackish foraminifera ( Polysaccammina, Pseudothurammina) and anchialine gastropods (˜95%, >300 individuals) indicate a brackish anchialine habitat developed in the elevated caves after the prolonged littoral environmental phase. The onset of sea-level regression following the +21 m highstand would first lower the ancient brackish Ghyben-Herzberg lens (<0.5 m) and flood the cave with brackish water, followed by drainage of the cave to create a permanent vadose environment. These interpretations of the MIS 11 microfossils (considering both taphonomy and paleoecology) are congruent with the micropaleontological, hydrogeological and physical mechanisms influencing modern Bermudian coastal cave environments. In

  13. A 4D Framework for Ocean Basin Paleodepths and Eustatic Sea Level Change

    NASA Astrophysics Data System (ADS)

    Muller, R.; Sdrolias, M.; Gaina, C.

    2006-12-01

    A digital framework for paleobathymetry of the ocean basins requires the complete reconstruction of ocean floor through time, including the main ocean basins, back-arc basins, and now subducted ocean crust. We reconstruct paleo-oceans by creating "synthetic plates", the locations and geometry of which is established on the basis of preserved ocean crust (magnetic lineations and fracture zones), geological data, and the rules of plate tectonics. We reconstruct the spreading histories of the Pacific, Phoenix, Izanagi, Farallon and Kula plates, the plates involved in the Indian, Atlantic, Caribbean, Arctic, Tethys and Arctic oceanic domains and all plates involved in preserved backarc basins. Based mainly on the GML-standards compliant GPlates software and the Generic Mapping Tools, we have created a set of global oceanic paleo-isochrons and paleoceanic age and depth grids. We show that the late-Cretaceous sea level highstand and the subsequent long-term drop in sea level was primarily caused by the changing age-area distribution of Pacific ocean floor through time. The emplacement of oceanic plateaus has resulted in a 40 m sealevel rise between 125 and 110 Ma, and a further 60 m rise after 110 Ma, whereas the oceanic age and latitude dependence of marine sediments has resulted in a 40m sealevel rise since about 120Ma, offsetting the gradual post-80Ma drop in sealevel due to the ageing and deepening mainly of the Pacific ocean basin, with the net effect being an about 200m drop after 80 Ma. Between 140 Ma and the present, oceanic crustal production dropped by over 40% in the Pacific, but stayed roughly constant in the remaining ocean basins. Our results suggest that the overall magnitude of 1st order sealevel change implied by Haq's sea level curve is correct.

  14. Monitoring Global Sea Level: Eustatic Variations, Local Variations, and Solid Earth Effects

    NASA Technical Reports Server (NTRS)

    Davis, James L.

    2000-01-01

    Project BIFROST (Baseline Inferences for Fennoscandian Rebound Observations. Sea-level and Tectonics) combines networks of continuously operating CPS receivers in Sweden and Finland to measure ongoing crustal deformation due to glacial isostatic adjustment, (CIA). We present an analysis of data collected in the years 1993-1998. We compare the CPS determinations of three-dimensional crustal motion to predictions calculated using the high resolution Fennoscandian deglaciation model recently proposed by Lambeck et al. We find that the the maximum observed uplift rate (approx. 10 mm/ yr) and the maximum predicted uplift rate agree to better than 1 mm/ yr. The patterns of uplift also agree quite well, although differences are discernible. The chi(exp 2) difference between predicted and GPS-observed radial rates is reduced by a factor of 5-6 compared to that for the "null" (no uplift) model, depending on whether a mean difference is first removed. The north components of velocity agree at about the same relative level. whereas the agreement for the east components is worse, a problem possibly related to the lack of bias fixing. We have also compared the values for the observed radial deformation rates to those based on sea-level rates from Baltic tide gauges. The weighted RMS difference between CPS and tide-gauge rates (after removing a mean) is 0.6 mm/ yr, giving an indication of the combined accuracy of the CPS and tide-gauge measurement systems. Spectral analysis of the time series of position estimates yields spectral indices in the range -1 to -2. An EOF analysis indicates, however, that much of this power is correlated among the sites. The correlation appears to be regional and falls off only slightly with distance. Some of this correlated noise is associated with snow accumulation on the antennas or, for those antennas with radomes, on the radomes. This problem has caused us to modify the radomes used several times, leading to one of our more significant sources

  15. Discovery of Lower Pleistocene Shallow-marine Deposits on Mayaguana Island, Bahamas. Implications for Eustatic Sea-Level Curves Derived From Deep-Sea Oxygen-Isotope Records

    NASA Astrophysics Data System (ADS)

    Godefroid, F.; Kindler, P.; Chiaradia, M.; Hasler, C.; Samankassou, E.

    2008-12-01

    87Sr/86Sr-dated marine and beach sediments exposed along the north shore of Mayaguana Island (Bahamas) provide new estimates of the elevation of high sea stands during the Early Pleistocene that will contribute to better calibrate eustatic sea-level curves derived from deep-sea oxygen-isotope records. A newly investigated sea cliff located to the west of Mount Misery Point on the northern coast of Mayaguana, in the SE part of the Bahamian archipelago, includes two vertically stacked sequences of shallow-marine carbonates separated and capped by paleosols and eolianites. The lower unit, reaching up to 5.5 m above modern sea level, consists of coarse laminated calcarenites containing numerous mollusk and red-algal fragments, and large in-situ coral specimens (Diploria strigosa). The second unit, exposed between 7.3 and 10 m, includes bioturbated, coral-rich limestones, overlain by thinly bedded calcarenites characterized by an early generation of fibrous rim cement. 87Sr/86Sr ratios measured from these carbonates range from 0.709123 at the base of the section to 0.709142 at its top. The first unit can be interpreted as a peri-reefal facies deposited when relative sea level was at least 5.5 m above present. The second unit corresponds to one shallowing-upward sequence of subtidal and beach deposits generated when sea level was around 9 m above its actual stand. Sr-isotope ratios indicate that both units were formed during the Early Pleistocene, likely between 1.6 and 1.0 Ma BP. Comparison with existing oxygen-isotope records from deep- sea sediments suggests that the identified sea-level highstands could correspond to negative δ18O peaks estimated at 1.45 and 1.50 Ma BP. Based on the elevation of fossil reefs dating from the last interglacial (Marine Isotope Stage 5e) and the occurrence of Upper Miocene shallow-marine deposits close to modern sea level, Mayaguana can be considered as tectonically stable. The elevation values obtained for these Early Pleistocene

  16. The whole-rock cerium anomaly: a potential indicator of eustatic sea-level changes in shales of the anoxic facies

    NASA Astrophysics Data System (ADS)

    Wilde, Pat; Quinby-Hunt, Mary S.; Erdtmann, Bernd-Dieter

    1996-01-01

    The whole-rock cerium anomaly, tested for outer shelf-upper slope stratigraphic sections from the middle Ordovician through the lower Silurian of Scotland, is proposed as an empirical technique to develop a eustatic 3rd-order or finer-scale sea-level curve. This interval was chosen as it straddles the well-documented Late Ordovician glaciation and can be defined by graptolite zones. The anomaly is calculated from neutron activation analysis of low-carbonate, phosphate-free, fossil-free field-identified shales of the graptolite facies by comparison of the normalized cerium content with the linearized trend of the normalized composition of other rare earth elements in order of atomic number. For sections originally deposited in the main pycnocline below the surface mixed layer, values of the anomaly for a given sample would indicate its position on the redox curves developed for the early Paleozoic by Wilde (1987). Changes in the anomaly that are positive with time would indicate a lowering of sea level as the apparent depth on the redox curve would reflect more oxic conditions. Relative changes negative with time would indicate a rise in sea level as the apparent depth reflects more anoxic conditions. Depending on the vertical sample spacing and the time interval sampled, resolution of the order of 1 m.y. might be achieved. Thus the Vail et al. (1977) curves of the 3rd order (1 to 10 m.y.) or of finer scale could be obtained by this technique with the proper choice of section. Accordingly, for the early through middle Paleozoic when the main pycnocline was anoxic, this geochemical technique could be used to develop eustatic sea-level curves and additionally offer an independent calibration for seismic stratigraphy as well as an indicator of glacial-interglacial climatic sequences or eustatic changes due to fluctuations in global ridge crest volumes.

  17. Glacial-eustatic sea-level fluctuation curve for Carboniferous-Permian boundary strata based on outcrops in the North American Midcontinent and North-Central Texas

    SciTech Connect

    Boardman, D.R. . School of Geology)

    1993-02-01

    Based on lithologic and faunal analysis of uppermost Carboniferous through Lower Permian strata (Wabaunsee through lower Chase groups) exposed from southeastern Nebraska through north-central Oklahoma, a preliminary glacial-eustatic sea-level fluctuation curve is presented herein. In addition to the sea-level curve presented for the Midcontinent region, one for coeval outcropping strata (middle and upper Cisco Group) of the Eastern Shelf of the Midland Basin is also presented based on similar criteria. This sea-level curve is derived from new field studies as well as a refinement of earlier curves presented by Harrison (1973), and Boardman and Malinky (1985). The conclusion on the nature of the Carboniferous-Permian boundary strata cyclothems in the Midcontinent is mirrored by the results of that from North-Central Texas. Each of the primary biostratigraphically-based picks for the Carboniferous-Permian boundary coincide with either intermediate of major cycles in both study areas. Utilization of a glacial-eustatic maximum transgressive event for the Carboniferous-Permian boundary should result in a more correlatable level for intercontinental correlation.

  18. De-confounding of Relations Between Land-Level and Sea-Level Change, Humboldt Bay, Northern California: Uncertain Predictions of Magnitude and Timing of Tectonic and Eustatic Processes

    NASA Astrophysics Data System (ADS)

    Gilkerson, W.; Leroy, T. H.; Patton, J. R.; Williams, T. B.

    2010-12-01

    Humboldt Bay in Northern California provides a unique opportunity to investigate the effects of relative sea level change on both native flora and maritime aquiculture as influenced by both tectonic and eustatic sea-level changes. This combination of superposed influences makes quantitatively predicting relative sea-level more uncertain and consumption of the results for public planning purposes exceedingly difficult. Public digestion for practical purposes is confounded by the fact that the uncertainty for eustatic sea-level changes is a magnitude issue while the uncertainty associated with the tectonic land level changes is both a magnitude and timing problem. Secondly, the public is less well informed regarding how crustal deformation contributes to relative sea-level change. We model the superposed effects of eustatic sea-level rise and tectonically driven land-level changes on the spatial distribution of habitats suitable to native eelgrass (Zostera marina) and oyster mariculture operations in Humboldt Bay. While these intertidal organisms were chosen primarily because they have vertically restricted spatial distributions that can be successfully modeled, the public awareness of their ecologic and economic importance is also well developed. We employ easy to understand graphics depicting conceptual ideas along with maps generated from the modeling results to develop locally relevant estimates of future sea level rise over the next 100 years, a time frame consistent with local planning. We bracket these estimates based on the range of possible vertical deformation changes. These graphic displays can be used as a starting point to propose local outcomes from global and regional relative sea-level changes with respect to changes in the distribution of suitable habitat for ecologically and economically valuable species. Currently the largest sources of uncertainty for changes in relative sea-level in the Humboldt Bay area are 1) the rate and magnitude of tectonic

  19. Simulation of continental basin margin sedimentation in response to crustal movements, eustatic sea level change, and sediment accumulation rates

    SciTech Connect

    Helland-Hansen, W.; Kendall, C.G.St.C.; Lerche, I.; Nakayama, K.

    1988-10-01

    As eustasy, subsidence, and sediment accumulation vary, a 2D computer-based graphical simulation generates on-lapping and off-lapping geometries of both marine and near coastal alluvial deposits, reproducing timelines within sediment-bodies at basin margins. In the simulation, deposition is expressed by creation of new surfaces above previous ones. Thicknesses of layers are reduced by both erosion and compaction while their surfaces move vertically in response to tectonic change and loading. Simulation is divided into a series of equal time steps in which sediment is deposited as an array of en-echelon columns that mark the top of the previous depositional surface. The volume of sediment deposited in each time step is expressed as a 2D cross section and is derived from two right-angle triangles (sand and shale), whose areas are a 2D expression of the quantity of sediment deposited at that time step and whose length matches the width of the offshore sediment wedge seaward of the shoreline. Each column in the array is filled by both marine sediments up to sea level, and alluvial sediments to a surface determined by an alluvial angle that is projected landward from the shore to its intersection with the previous surface. Each time the area representing the sediment column is subtracted from the triangles, the triangle heights are reduced correspondingly. This process is repeated until the triangle heights match the position of sea level above the sediment surface, at which time the remaining area of the sediment triangle is deposited seaward as a single wedge of offshore sediments. This simulation is designed to aid interpretation of stratigraphic sequences. It can be used as a complement to seismic stratigraphy or can be used alone as an inexpensive test of stratigraphic models.

  20. Evaluating the fate of freshwater lenses on atoll islands after eustatic sea-level rise and cyclone-driven inundation: A modelling approach

    NASA Astrophysics Data System (ADS)

    Terry, James P.; Chui, Ting Fong May

    2012-05-01

    Dispersed human populations inhabiting remote atolls across the tropical Pacific Ocean are reliant on the viability of thin freshwater lenses (FWLs) contained within the island coralline sediments for their survival. Yet FWLs are uniquely fragile and easily damaged by saline intrusion. Eustatic sea-level rise (SLR) and sea flooding generated by intense tropical cyclones therefore pose special perils for continued existence on atolls. In this work, mathematical modelling is used to examine the effects on an atoll freshwater lens of various projected long-term SLR scenarios (10, 20, and 40 cm). A cyclone-driven wave washover event is then simulated in order to observe the responses and recovery of the FWL, subsequent to the SLR scenarios imposed. A key attribute of our model design is the inclusion of a topographic depression containing a low-lying fresh swamp in the atoll islet interior (which is often ignored), where seawater accumulates during inundation. Results indicate that a 40 cm SLR produces a major impact: the FWL decreases in thickness by approximately 50%, develops a brackish centre and contracts to a shrunken 'doughnut' morphology. Following cyclone inundation, observed salinity profiles are illuminating. Steep salinity gradients show how a strong saline plume forms at shallow depths, but also reveal the existence of an undisturbed fresh horizon beneath the salt plume under both present conditions and the modest 10 cm SLR scenario. Within the preserved fresh horizon, salt concentrations are maintained below 1.5 g/L (i.e. within usable limits) for at least a year. In contrast, the diminished freshwater lenses that exist after 20 and 40 cm SLR then exhibit far less resilience to saline damage over comparable post-cyclone timeframes. The findings point towards Pacific atolls becoming increasingly uninhabitable long before their complete submergence by sea-level rise, owing to irrecoverable groundwater salinisation seriously reducing the availability of

  1. Climatic, eustatic, and tectnoic controls on Quarternary deposits and landforms, Red Sea coast, Egypt

    NASA Technical Reports Server (NTRS)

    Arvidson, Raymond; Becker, Richard; Shanabrook, Amy; Luo, Wei; Sturchio, Neil; Sultan, Mohamed; Lofty, Zakaria; Mahmood, Abdel Moneim; El Alfy, Zeinhom

    1994-01-01

    The degree to which local climatic variations, eustatic sea level fluctuations, and tectonic uplift have influenced the development of Quaternary marine and fluvial landforms and deposits along the Red Sea coast, Eastern Desert, was investigated using a combination of remote sensing and field data, age determinations of corals, and numerical simulations. False color composites generated from Landsat Thematic Mapper and SPOT image data, digital elevation models derived from sterophotogrammetric analysis of SPOT data, and field observations document that a approximately 10-km wide swath inland from the coast is covered in many places with coalescing alluvial fans of Quaternary age. Wadis cutting through the fans exhibit several pairs of fluvial terraces, and wadi walls expose alluvium interbedded with corraline limestone deposits Further, three distinct coral terraces are evident along the coatline. Climatic, eustatic, and tectonic uplift controls on the overall system were simulated using a cellular automata algorithm with the following characteristics: (1) uplift as a function of position and time, as defined by the elevations and ages of corals; (2) climatic variations driven by insolation changes associated with Milankovitch cycles; (3) sea level fluctuations based on U/Th ages of coral terraces and eustatic data; and (4) parametrized fluvial erosion and deposition. Results imply that the fans and coralline limestones were generated in a setting in which the tectonic uplift rate decreased over the Quarternary to negligible values at present. Coralline limestones formed furing eustatic highstands when alluvium was trapped uspstream and wadis filled with debris. During lowstands, wadis cut into sedimentary deposits; coupled with continuing uplift, fans were dissected, leaving remnant surfaces, and wadi-related terraces were generated by down cutting. Only landforms from the past three to four eustatic sea level cycles (i.e., approximately 300 to 400 kyr) are likely

  2. Climatic, eustatic, and tectonic controls on Quaternary deposits and landforms, Red Sea coast, Egypt

    SciTech Connect

    Arvidson, R.; Becker, R.; Shanabrook, A.; Luo, W.; Sultan, M.; Sturchio, N.; Lotfy, Z.; Mahmood, A.M.; El Alfy, Z.

    1994-06-10

    The degree to which local climatic variations, eustatic sea level fluctuations, and tectonic uplift have influenced the development of Quaternary marine and fluvial landforms and deposits along the Red Sea coast, Eastern Desert, Egypt was investigated using a combination of remote sensing and field data, age determinations of corals, and numerical simulations. False color composites generated from Landsat Thematic Mapper and SPOT image data, digital elevation models derived from stereophotogrammetric analysis of SPOT data, and field observations document that a {approximately}10-km-wide swath inland from the coast is covered in many places with coalescing alluvial fans of Quaternary age. Wadis cutting through the fans exhibit several pairs of fluvial terraces, and wadi walls expose alluvium interbedded with coralline limestone deposits. Further, three distinct coral terraces are evident along the coastline. Climatic, eustatic, and tectonic uplift controls on the overall system were simulated using a cellular automata algorithm with the following characteristics: (1) uplift as a function of position and time, as defined by the elevations and ages of corals; (2) climatic variations driven by insolation changes associated with Milankovitch cycles; (3) sea level fluctuations based on U/Th ages of coral terraces and eustatic data; and (4) parameterized fluvial erosion and deposition. Results imply that the fans and coralline limestones were generated in a setting in which the tectonic uplift rate decreased over the Quaternary to negligible values at present. During lowstands, wadis cut into sedimentary deposits; coupled with continuing uplift, fans were dissected, leaving remnant surfaces, and wadi-related terraces were generated by down cutting. Only landforms from the past three to four eustatic sea level cycles (i.e., {approximately} 300 to 400 kyr) are likely to have survived erosion and deposition associated with fluvial processes. 33 refs., 18 figs., 2 tabs.

  3. Humboldt Bay Vertical Reference System Working Group: unraveling tectonic and eustatic factors of sea level rise in northern California, Humboldt Bay

    NASA Astrophysics Data System (ADS)

    Williams, T. B.; Anderson, J. K.; Burgette, R. J.; Gilkerson, W.; Hemphill-Haley, M.; Leroy, T. H.; Patton, J. R.; Southwick, E.; Stallman, J.; Weldon, R. J.

    2012-12-01

    Sea-level rise is a critical factor in managing estuarine ecosystems, maintaining public infrastructure, and mitigating geologic hazards along north coastal California. The coastal region between Fort Bragg, California and Vancouver Island experiences ongoing land-level changes due to Cascadia subduction zone tectonics. These tectonic land-level changes sufficiently modify relative sea level such that sea-level rise cannot be accurately estimated without determining the tectonic contribution. We use tide gages and precise level-loop surveys to observe modern land and water surface elevations around Humboldt Bay. These modern data, combined with historic survey data, will be used to deconfound the various factors contributing to relative sea level change. Independent analysis of existing NOAA tide gages and EarthScope CGPS stations indicate 2.5 mm/yr of land subsidence near Humboldt Bay and 2 mm/yr of land uplift in Crescent City. Presuming the bulk of the strain accumulation is due to the southern portion of the Cascadia subduction zone, these data suggest Humboldt Bay is west of the locked zone, not to the east as previously reported by several researchers.

  4. Paleo-surfaces of glacio-eustatically forced aggradational successions in the coastal area of Rome: Assessing interplay between tectonics and sea-level during the last ten interglacials

    NASA Astrophysics Data System (ADS)

    Marra, Fabrizio; Florindo, Fabio; Anzidei, Marco; Sepe, Vincenzo

    2016-09-01

    Recently acquired geochronological and stratigraphic data provide new information on the sedimentary successions deposited by the Paleo-Tiber River in the coastal and near-coastal area of Rome in consequence of the glacio-eustatic changes, allowing to better define their inner geometry and palaeogeographic spatial distribution. In the present work we use this revised sedimentary dataset to provide a geochronologically constrained and tectonically adjusted record of paleo sea-level indicators. Aimed at this scope, we review literature data acquired in the last 35 years and using the new geochronological constraints we pinpoint the coastal-to-fluvial terraces of MIS 5 and MIS 7, mapping their relic surfaces in an area of 30 km along the coast north and south of the Tiber River mouth, and 20 km inland of the fluvial valleys of Tiber and Aniene rivers. The geometry of these paleo-surfaces provides constraints on the relative elevation of the sea-level during the last interglacials and on the uplift rates in this region during the last 200 ka. In particular, we recognize the previously undetected terraces of MIS 5.3 and MIS 5.1 interstadials, and we assess their spatial relationship with respect to MIS 5.5, providing important information on sea-level oscillations during this time span. Comparison with sea-level indicators provided by previous aggradational successions deposited during past interglacials spanning MIS 9 through MIS 21 in the coastal area of Rome, also allows us to reconstruct the tectonic history and investigate its relationships with the Middle-Pleistocene volcanic activity of the Roman Comagmatic Region along the Tyrrhenian Sea margin of Italy in the last 900 ka.

  5. Bay sedimentation as controlled by regional crustal behaviour, local tectonics and eustatic sea-level changes: Coquimbo Formation (Miocene Pliocene), Bay of Tongoy, central Chile

    NASA Astrophysics Data System (ADS)

    Le Roux, J. P.; Olivares, Danisa M.; Nielsen, Sven N.; Smith, Norman D.; Middleton, Heather; Fenner, Juliane; Ishman, Scott E.

    2006-02-01

    The north-facing Bay of Tongoy in central Chile is flanked by topographic highs in the west and east. During the Miocene and Pliocene, the bay extended inland at least 30 km farther south than a present. It was filled with muds, sands, coquinas and gravel during a series of transgressions and regressions related to regional and local tectonic movements combined with global sea-level variations. 87Sr/ 86Sr and microfossil dating indicates transgressions between 11.9-11.2 Ma, 10.1-9.5 Ma, 9.0-7.3 Ma, 6.3-5.3 Ma, 4.3-2.2 Ma and 1.7-1.4 Ma. The regional tectonic behaviour of the crust shows general uplifting from 10.5 Ma to 6.9 Ma, associated with subduction of the Juan Fernández Ridge (JFR) beneath this part of the continent. Subsidence followed between 6.9 and 2.1 Ma, in the wake of the southeastward-migrating JFR. The subsequent subduction of an oceanic plateau similar to the JFR caused rapid uplift that led to the final emergence of the bay above sea level. The Puerto Aldea normal fault along the western limit of the study area was reactivated during the regional uplift and subsidence events, with reverse faulting occurring during the latter phase. Sporadic fault reactivation probably triggered the rapid changes in water depth reflected in the recorded vertical succession of facies.

  6. Eustatic and climatic control on the Upper Muschelkalk Sea (late Anisian/Ladinian) in the Central European Basin

    NASA Astrophysics Data System (ADS)

    Franz, M.; Kaiser, S. I.; Fischer, J.; Heunisch, C.; Kustatscher, E.; Luppold, F. W.; Berner, U.; Röhling, H.-G.

    2015-12-01

    The Upper Muschelkalk in the Central European Basin (CEB) is a key example of eustatic and climatic controls on inland seas. The late Anisian rapid transgression from Tethyan waters culminated in a large semi-enclosed inland sea stretching across the CEB. Subsequently, the slow but successive retreat in the early Ladinian resulted in a small remnant sea. The pronounced stratal pattern architectures are translated into a framework of 3rd- and 4th-order T-R sequences. The latest Illyrian 3rd-order maximum flooding surface corresponds to maximum abundances of carbonates and marine phytoplankton. An euryhaline marine ecology is indicated by prasinophycean algae dominating over acritarchs and δ18OP values of 18.9-22.4‰ VSMOW corresponding to Tethyan references. During the 3rd-order regressive phase successive freshening up to hyposaline conditions is indicated by up to 3‰ depleted δ18OP values, shifts to more radiogenic 87Sr/86Sr ratios and maximum abundances of terrestrial palynomorphs. Likewise, 4th-order T-R sequences are constrained by commutated stratal pattern architectures, palynofacies and geochemistry. The favourable correlation of middle Triassic 3rd-order sequences of Tethyan and peri-Tethyan basins demonstrate the principle control of circum-Tethyan eustatic cycles. 4th-order sequences are evident and, although not yet correlatable in detail, indicate 106-year scale eustatic cycles which may be attributed to glacioeustatic sea-level changes. The subordinated control of arid to semiarid low latitude and semihumid to humid temperate mid latitude climates affected the Upper Muschelkalk Sea in particular during 4th-order sea-level lowstands. Substantial fresh water input from Scandinavian sources caused temporal stratification leading to stagnant bottom waters and/or sediments as indicated by palynofacies and U/Th and Ni/Co redox indices. The herein reconstructed middle Triassic zonal climates are in agreement to previously published Late Triassic zonal

  7. A "chaos" of Phanerozoic eustatic curves

    NASA Astrophysics Data System (ADS)

    Ruban, Dmitry A.

    2016-04-01

    The knowledge of eustasy has changed during the past two decades. Although there is not any single global sea-level curve for the entire Phanerozoic, new curves have been proposed for all periods. For some geological time intervals, there are two and more alternative reconstructions, from which it is difficult to choose. A significant problem is the available eustatic curves are justified along different geological time scales (sometimes without proper explanations), which permits to correlate eustatic events with the possible error of 1-3 Ma. This degree of error permits to judge about only substage- or stage-order global sea-level changes. Close attention to two geological time slices, namely the late Cambrian (Epoch 3‒Furongian) and the Late Cretaceous, implies that only a few eustatic events (6 events in the case of the late Cambrian and 9 events in the case of the Late Cretaceous) appear on all available alternative curves for these periods, and different (even opposite) trends of eustatic fluctuations are shown on these curves. This reveals significant uncertainty in our knowledge of eustasy that restricts our ability to decipher factors responsible for regional transgressions and regressions and relative sea-level changes. A big problem is also inadequate awareness of the geological research community of the new eustatic developments. Generally, the situation with the development and the use of the Phanerozoic eustatic reconstructions seems to be "chaotic". The example of the shoreline shifts in Northern Africa during the Late Cretaceous demonstrates the far-going consequences of this situation. The practical recommendations to avoid this "chaos" are proposed. Particularly, these claim for good awareness of all eustatic developments, their critical discussion, and clear explanation of the employed geological time scale.

  8. Tors, Eustatic Shorelines, and Mammoths: Evidence Against Ice Sheets on Wrangel Island, East Siberian/Chukchi Seas

    NASA Astrophysics Data System (ADS)

    Gualtieri, L.; Vartanyan, S.; Brigham-Grette, J.; Anderson, P.

    2001-12-01

    Assumed glacial flutings on the Chukchi Rise (Polyak et al., 2001) have reinvigorated hypotheses concerning the past presence of the same type of ice sheet or ice shelf on the Chukchi and/or East Siberian Sea shelf. Fieldwork on wrangle Island has been aimed at determining the glacial and sea level history of this geographically strategic island to address these various hypotheses. Cosmogenic isotope ages (Be and Al) on bedrock are all older that 35 ka , at a minimum, the rates of pervasive pariglacial processes. Tors, commonly forming columns 10 m high, are ubiquitous throughout the mountains of Wrangel Island. Eustatic shorelines (and not glacioisostatic shorelines) across the northern tundra plain marked by remnant marine sediments and ancient barrier beaches up to 40 m above seal level are all older than the range of radiocarbon dating and yield amino acid age estimates (D/L Aspartic as well as aIle/Ile) in excess of 400-500 ka, similar to sediments found in the Alaskan North Slope. Radiocarbon dates on mammoth borres, teeth and tusks and other animals (rhinos, bison) yield ages that range continuously through time from >38 ka to 3700 years ago indicating the local presence of large mammals during the Last Glacial Maximum (LGM) and most of the Holocene. These data preclude the presence of an ice sheet during the LGM and probably over the past half million years. Glacial ice extent on the island during the LGM was limited to a few small north facing cirque glaciers. The flutings on the Chukchi Rise could not have been formed by an ice sheet over or near Wrangel Island in at least the last four or five major glacial/interglacial cycles.

  9. Record of glacial-eustatic sea-level fluctuations in complex middle to late Pennsylvanian facies in the Northern Appalachian Basin and relation to similar events in the Midcontinent basin

    NASA Astrophysics Data System (ADS)

    Belt, Edward S.; Heckel, Philip H.; Lentz, Leonard J.; Bragonier, William A.; Lyons, Timothy W.

    2011-06-01

    Pennsylvanian cycles in the Northern Appalachian Basin (NAB) were historically considered to result from delta-lobe switching, and more recently from sea-level fluctuation with sandy deltas prograding during highstand. These interpretations are revised using new data from cores and outcrop exposures. Thick (> 5 m) channel deposits with a marked erosion surface at their base cutting down across previous cycles are re-interpreted as incised valley fill (IVF) deposits in paleovalleys, because the basal erosion surfaces are widespread, and thus reflect a record of lowstand. Most common are simple paleovalleys that contain mainly sandy fluvial deposits. Compound paleovalleys with sequence boundaries above the basal erosion surface, contain terrestrial, estuarine, and marine deposits. Early to late highstand deposits in interfluvial parts of the cycles are dominated by shale and mudstone, with paleosols, coals, and local non-marine limestone, which reflect floodbasin to lacustrine conditions. These reinterpretations are applied to previously and newly recognized cycles in ascending order: Upper Kittanning, Lower Freeport, Upper Freeport Leader (new), Upper Freeport, Piedmont (new), Mahoning, Mason interval (locally includes Upper New Galilee in the north), and Brush Creek, across a 300-km arc in the Northern Appalachian Basin. These deposits accumulated in a 'high shelf' setting that experienced fewer marine transgressions, and were interrupted by more frequent exposure and downcutting, in contrast to the thicker and more complete succession with more numerous marine units in the Midcontinent. Magnitudes of highstand transgressions into this basin, deduced from the up-dip extent of marine and brackish fossil assemblages, were greatest for the Brush Creek, less so for the Upper Kittanning and Mahoning, and least for the Lower Freeport, Upper Freeport Leader, Piedmont, and Mason. The anomalous basin-wide fresh-water roofshales and equivalents of the Upper Freeport coal may

  10. Sea-Level Changes during the Tertiary.

    ERIC Educational Resources Information Center

    Vail, Peter R.; Hardenbol, Jan

    1979-01-01

    Discussed are research procedures undertaken to determine the magnitude and timing of eustatic sea-level changes during the Tertiary Period. Data now becoming available give scientists a knowledge of conditions that may have been conducive to the formation of petroleum. (BT)

  11. Two Sea-Level Challenges

    NASA Astrophysics Data System (ADS)

    Galvin, C.

    2008-12-01

    "No place on the sandy ocean shores of the world has been shown to be eroding because of sea level rise." This statement appeared nearly 19 years ago in bold print at the top of the page in a brief article published in Shore and Beach (Galvin,1990). The term "sea level rise" was defined in 1990 as follows: "In this statement, "sea level rise" has the meaning that the average person on the street usually attaches to that term. That is, sea level is rising; not, as in some places like the Mississippi River delta, land level is sinking." While still a subject of controversy, it is now (2008) increasingly plausible (Tornqvist et al,2008) that damage from Hurricane Katrina was significantly worse on the Mississippi River delta because floodwaters exploited wetlands and levees whose elevations had been lowered by decades of compaction in the underlying soil. (1) "Sea level" commonly appears in the literature as "relative sea level rise", occurring that way in 711 publications between 1980 and 2009 (GeoRef database on 8 Sep 08). "Relative sea level rise" does not appear in the 2005 AGI Glossary. The nearest Glossary term is "relative change in sea level", but that term occurs in only 12 publications between 1980 and 2009. The Glossary defines this term in a sequence stratigraphy sense, which infers that "relative sea level rise" is the sum of bottom subsidence and eustatic sea level rise. In plain English, "relative sea level rise" means "water depth increase". For present day coastal environments, "relative sea level rise" is commonly used where eustatic sea level rise is less than subsidence, that is, where the magnitude of actual sea level rise is smaller than the magnitude of subsidence. In that situation, "relative sea level rise" misleads both the average person and the scientist who is not a coastal geologist. Thus, the first challenge is to abandon "relative sea level rise" in favor of "water depth increase", in order that the words accurately descibe what happens

  12. Revisiting Tectonic Corrections Applied to Pleistocene Sea-Level Highstands

    NASA Astrophysics Data System (ADS)

    Creveling, J. R.; Mitrovica, J. X.; Hay, C.; Austermann, J.; Kopp, R. E.

    2015-12-01

    The robustness of stratigraphic- and geomorphic-based inferences of Quaternary peak interglacial sea levels — and equivalent minimum continental ice volumes — depends on the accuracy with which highstand markers can be corrected for vertical tectonic displacement. For sites that preserve a Marine Isotope Stage (MIS) 5e sea-level highstand marker, the customary method for estimating tectonic uplift/subsidence rate computes the difference between the local elevation of the highstand marker and a reference eustatic (i.e., global mean) MIS 5e sea-level height, typically assumed to be +6 m, and then divides this height difference by the age of the highstand marker. This rate is then applied to correct the elevation of other observed sea-level markers at that site for tectonic displacement. Subtracting a reference eustatic value from a local MIS 5e highstand marker elevation introduces two potentially significant errors. First, the commonly adopted peak eustatic MIS 5e sea-level value (i.e., +6 m) is likely too low; recent studies concluded that MIS 5e peak eustatic sea level was ~6-9 m. Second, local peak MIS 5e sea level was not globally uniform, but instead characterized by significant departures from eustasy due to glacial isostatic adjustment (GIA) in response to successive glacial-interglacial cycles and excess polar ice-sheet melt relative to present day. We present numerical models of GIA that incorporate both of these effects in order to quantify the plausible range in error of previous tectonic corrections. We demonstrate that, even far from melting ice sheets, local peak MIS 5e sea level may have departed from eustasy by 2-4 m, or more. Thus, adopting an assumed reference eustatic value to estimate tectonic displacement, rather than a site-specific GIA signal, can introduce significant error in estimates of peak eustatic sea level (and minimum ice volumes) during Quaternary highstands (e.g., MIS 11, MIS 5c and MIS 5a).

  13. The Sea Level Conundrum: Insights From Paleo Studies

    NASA Astrophysics Data System (ADS)

    Siddall, Mark; Clark, Peter; Thompson, Bill; Waelbroeck, Claire; Gregory, Jonathan; Stocker, Thomas

    2009-03-01

    Empirical Constraints on Future Sea Level Rise; Bern, Switzerland, 25-29 August 2008; Eustatic sea level (ESL) rise during the 21st century is perhaps the greatest threat from climate change, but its magnitude is contested. Geological records identify examples of nonlinear ice sheet response to climate forcing, suggesting a strategy for refining estimates of 21st-century sea level change. In August 2008, Past Global Changes (PAGES), International Marine Past Global Change Study (IMAGES), and the University of Bern cosponsored a workshop to address this possibility. The workshop highlighted several ways that paleoceanography studies can place limits on future sea level rise, and these are enlarged upon here.

  14. The Cambrian eustatic signal: Not so grand

    SciTech Connect

    Cowan, C.A.; James, N.P. )

    1990-05-01

    Efforts to decipher potential high-frequency (fourth- and fifth-order) eustatic signals within third-order grand cycles in Cambrian strata of western Newfoundland have yielded a surprising result: the conspicuous, large-scale stratigraphic rhythms, grand cycles, were not principally a bathymetric phenomenon, grand cycles, i.e., the stratigraphic repetition of tens-of-meters-thick lithosomes, which are alternately carbonate and terrigenous clastic rich, are widely cited as evidence for lower Paleozoic third-order eustatic fluctuations. Evidence from Middle to Upper Cambrian platform strata in western Newfoundland indicates that grand cyclicity in this area was not simply a response to sea level change. Instead, the stratigraphic signal of eustasy is marked by the presence of terrigenous clastics in an otherwise carbonate-prone succession. Detailed facies analysis reveals that both terrigenous and carbonate lithosomes are locally constructed of predictable, meter-scale, coarsening-upward cycles. Lithofacies constituting meter-scale cycles in both lithosomes are bathymetrically indistinguishable with respect to environmental energy, ichnofauna, and exposure index. Meter-scale cycles in either lithosome are typically capped by the same lithology, precluding contemporaneous generation of carbonate vs. terrigenous cycles along some presumed bathymetric gradient. Obvious lithologic differences between carbonate and terrigenous meter-scale cycles obscure their common origin. Terrigenous cycles are best explained by the incursion of siliciclastic fines into a shallow-water carbonate environment irrespective of sea level change.

  15. Sea level rise and coastal erosion

    NASA Astrophysics Data System (ADS)

    Leatherman, S. P.; Zhang, K.; Douglas, B. C.

    2003-04-01

    One of the most certain consequences of global warming is an increase of global (eustatic) sea level. The resulting inundation from rising seas will heavily impact low-lying areas; at least 100 million persons live within one meter of mean sea level and are at increased risk in the coming decades. The very existence of some island states and deltaic coasts is threatened by sea level rise. An additional threat affecting some of the most heavily developed and economically valuable real estate will come from an exacerbation of sandy beach erosion. As the beach is lost, fixed structures nearby are increasingly exposed to the direct impact of storm waves, and will ultimately be damaged or destroyed unless expensive protective measures are taken. It has long been speculated that the underlying rate of long-term sandy beach erosion is two orders of magnitude greater than the rate of rise of sea level, so that any significant increase of sea level has dire consequences for coastal inhabitants. We present an analysis of a large and consistent database of shoreline positions and sea levels to show that there is an underlying highly multiplicative relation of sandy beach erosion to sea level rise. This result means that the already-severe coastal erosion problems witnessed in the 20th century will be exacerbated in the 21st century under plausible global warming scenarios.

  16. Bajocian-Bathonian (Middle Jurassic) sea-level changes in northeastern Egypt: Synthesis and further implications

    NASA Astrophysics Data System (ADS)

    Ruban, Dmitry A.; Sallam, Emad S.

    2016-08-01

    The global eustatic developments can benefit significantly from properly acquired regional information. Summarizing the available interpretations of the relative sea-level changes from two areas in northeastern Egypt, namely Gebel Maghara and Khashm El-Galala, allows better understanding of the Middle Jurassic sea-level changes. It is established that the Bajocian-Bathonian relative sea-level changes in these areas were coherent. The magnitude of changes was lower in the Bajocian than in the Bathonian. Significant sea-level rises occurred at the Bajocian-Bathonian and middle-late Bathonian transitions, and there was a clear tendency toward sea-level rise throughout the studied time interval. This evidence favors one of the two alternative global eustatic reconstructions that implies "stable" position of the shoreline in the Bajocian and general tendency to eustatic rise throughout the Jurassic. The tectonic regime of northeastern Egypt in the Middle Jurassic provided for strong eustatic control of the relative sea-level changes. The possible influence of hotspot activity is questionable. Filling the accommodation space with materials derived from the eroded continent may explain some sea-level falls that are regionally documented.

  17. Land to sea record of the mega-eustatic cycle including the Messinian Salinity Crisis in the Mediterranean Andalusia

    NASA Astrophysics Data System (ADS)

    Jouannic, Gwénaël.; Gorini, Christian; Jolivet, Laurent; Clauzon, Georges; Suc, Jean-Pierre; Gargani, Julien; Melinte-Dobrinescu, Mihaela Carmen; Meyer, Bertrand

    2010-05-01

    The outstanding event of the Messinian Salinity Crisis is very well documented in the onshore Sorbas and Vera Andalusian basins where its process and chronology are now well-known (Gautier et al., 1994, Krijgsman et al., 1999; Clauzon et al., 2009). The detailed study of these basins was at the origin of the two-step scenario of the Messinian salinity crisis (Clauzon et al., 1996) which clarified several aspects of the "deep desiccated basin" model of Hsü et al. (1973). The scenario in two steps (first step: evaporite deposition in Mediterranean marginal basins between 5.96 and 5.60 Ma; second step: evaporites deposition between 5.60 and 5.46 Ma in the almost dried up Mediterranean central basins, and subaerial erosion and deep canyons formation on the margins; Clauzon et al., 1996, 2005, 2008) has now the broadest consensus within the scientific community (CIESM, 2008). The Sorbas and Vera basins present all the markers in terms of sequence stratigraphy whatever these events were caused by moderate or excessive sea-level changes: 1, coral reefs, showing the relative sea level before the crisis; 2, gypsum (120 m in thickness) deposited during the first sea level drop (about 150 m) between 5.96 and 5.60 Ma; 3, the widespread erosion surface during the maximum sea level fall(ca. -1500 m); 4, the re-flooding at 5.46 Ma These onshore markers have also been recorded in offshore seismic profiles, allowing a continuous mapping of the Messinian canyons from land to sea. These onshore and offshore areas (Mauffret et al., 2007; Ammar et al., 2008) have also undergone a tectonics according to their proximity to the Betic cordillera (the south of the Sorbas Basin was more affected for example). Stratigraphic markers of the messinian crisis are powerful tools to reconstruct the tectonic events since 5 Ma. This work has made possible the calibration of tectonic deformations on south Andalusia present-day onshore and offshore domains. Ammar, A., Mauffret, A., Gorini, C., Jabour

  18. Ice volume and sea level during the last interglacial.

    PubMed

    Dutton, A; Lambeck, K

    2012-07-13

    During the last interglacial period, ~125,000 years ago, sea level was at least several meters higher than at present, with substantial variability observed for peak sea level at geographically diverse sites. Speculation that the West Antarctic ice sheet collapsed during the last interglacial period has drawn particular interest to understanding climate and ice-sheet dynamics during this time interval. We provide an internally consistent database of coral U-Th ages to assess last interglacial sea-level observations in the context of isostatic modeling and stratigraphic evidence. These data indicate that global (eustatic) sea level peaked 5.5 to 9 meters above present sea level, requiring smaller ice sheets in both Greenland and Antarctica relative to today and indicating strong sea-level sensitivity to small changes in radiative forcing.

  19. Sea level data and techniques for detecting vertical crustal movements

    NASA Technical Reports Server (NTRS)

    Lennon, G. W.

    1978-01-01

    An attempt is made to survey problems, requirements, and the outlook for the future in the study of sea level time series so as to determine the relative movement of land and sea levels. The basic aim is to eliminate from the record the contributions from whatever marine dynamic phenomena respond to treatment, allowing the secular element to be identified with optimum clarity. Nevertheless the concept of sea level perturbation varies according to regional experience. The recent work of the Permanent Service for Mean Sea Level helps to eliminate geodetic noise from the series and makes it possible, perhaps, to treat the global mean sea level data bank so as to define eustatic changes in ocean volume which, in the present context, may be regarded as the final goal, allowing the identification of vertical crustal motion itself.

  20. Can eustatic charts go beyond first-order? Insights from the Permo-Triassic

    NASA Astrophysics Data System (ADS)

    Guillaume, Benjamin; Monteux, Julien; Pochat, Stéphane; Husson, Laurent; Choblet, Gaël

    2016-04-01

    To the first order, eustatic charts are in accord with our understanding of the geodynamic processes that control sea level. By extrapolation, second-order features are also thought to obey to the same rules, and are thus often taken for granted. But this assumption may be jeopardized by a close examination of a characteristic example. The Permo-Triassic period is characteristic for both its purported eustatic signal and its geodynamic and climatic setting are well defined and contrasted. Both the fragmentation of the Pangean supercontinent and the late Paleozoic melting of ice sheets argue for a rise of the eustatic sea level (ESL) whereas eustatic charts show the opposite. Here we review the possible mechanisms that could explain the apparent sea level low, and find that some of them do lower the ESL while others instead only modify the referential, either uplifting continents or tilting the margins where the control points are located. In the first category, we find that (i) dynamic deflections of the Earth surface above subduction zones and their location with respect to continents primarily control absolute sea level while the Pangean supercontinent forms and breaks up, (ii) endorheism that ubiquitously developed at the time of Pangean aggregation also contributed to lowering the ESL by storing water out of the oceanic reservoir. In the second category, we show that (i) the thermal uplift associated to supercontinental insulation and (ii) the dynamic uplift associated with the emplacement of a superplume both give rates of change in the range of long-term changes of ESL. We also show that (iii) the dynamic tilting of continental margins not only produces apparent sea level changes, but also modifies the absolute sea level, which in turn may end up in the paradoxical situation wherein fingerprints of ESL drop are found in the geological record whereas ESL is actually rising. We conclude that the establishment of second to third order absolute sea level changes

  1. New evidence for the Holocene sea-level high from the inner shelf, central Great Barrier Reef, Australia

    SciTech Connect

    Beaman, R.; Larcombe, P.; Carter, R.M. . Marine Geophysical Lab.)

    1994-10-03

    Radiocarbon dates from fossil oyster beds of intertidal origin on Magnetic island, north Queensland indicate that the local Holocene maximum of relative sea level was attained no later than 5660 [+-] 50 B.P. (conventional uncorrected age) and remained at 1.6--1.7 m above modern levels until 4040 [+-] 50 B.P. Given the tectonic stability of the area, this implies that eustatic sea level remained at its Holocene peak for at least ca. 1600 yr. The new high-precision sea-level data indicate sea levels 1--5 m higher than those of the same age inferred from buried mangrove deposits on the inner shelf in north Queensland. Uncertainties in deriving relative sea level from such mangrove deposits may be a significant source of error in worldwide attempts to distinguish the eustatic and crustal warping components of relative sea-level change, especially in the tropics.

  2. Twentieth century sea level: An enigma

    PubMed Central

    Munk, Walter

    2002-01-01

    Changes in sea level (relative to the moving crust) are associated with changes in ocean volume (mostly thermal expansion) and in ocean mass (melting and continental storage): ζ(t) = ζsteric(t) + ζeustatic(t). Recent compilations of global ocean temperatures by Levitus and coworkers are in accord with coupled ocean/atmosphere modeling of greenhouse warming; they yield an increase in 20th century ocean heat content by 2 × 1023 J (compared to 0.1 × 1023 J of atmospheric storage), which corresponds to ζgreenhouse(2000) = 3 cm. The greenhouse-related rate is accelerating, with a present value ζ̇greenhouse(2000) ≈ 6 cm/century. Tide records going back to the 19th century show no measurable acceleration throughout the late 19th and first half of the 20th century; we take ζ̇historic = 18 cm/century. The Intergovernmental Panel on Climate Change attributes about 6 cm/century to melting and other eustatic processes, leaving a residual of 12 cm of 20th century rise to be accounted for. The Levitus compilation has virtually foreclosed the attribution of the residual rise to ocean warming (notwithstanding our ignorance of the abyssal and Southern Oceans): the historic rise started too early, has too linear a trend, and is too large. Melting of polar ice sheets at the upper limit of the Intergovernmental Panel on Climate Change estimates could close the gap, but severe limits are imposed by the observed perturbations in Earth rotation. Among possible resolutions of the enigma are: a substantial reduction from traditional estimates (including ours) of 1.5–2 mm/y global sea level rise; a substantial increase in the estimates of 20th century ocean heat storage; and a substantial change in the interpretation of the astronomic record. PMID:12011419

  3. Twentieth century sea level: an enigma.

    PubMed

    Munk, Walter

    2002-05-14

    Changes in sea level (relative to the moving crust) are associated with changes in ocean volume (mostly thermal expansion) and in ocean mass (melting and continental storage): zeta(t) = zeta(steric)(t) + zeta(eustatic)(t). Recent compilations of global ocean temperatures by Levitus and coworkers are in accord with coupled ocean/atmosphere modeling of greenhouse warming; they yield an increase in 20th century ocean heat content by 2 x 10(23) J (compared to 0.1 x 10(23) J of atmospheric storage), which corresponds to zeta(greenhouse)(2000) = 3 cm. The greenhouse-related rate is accelerating, with a present value zeta(greenhouse)(2000) approximately 6 cm/century. Tide records going back to the 19th century show no measurable acceleration throughout the late 19th and first half of the 20th century; we take zeta(historic) = 18 cm/century. The Intergovernmental Panel on Climate Change attributes about 6 cm/century to melting and other eustatic processes, leaving a residual of 12 cm of 20th century rise to be accounted for. The Levitus compilation has virtually foreclosed the attribution of the residual rise to ocean warming (notwithstanding our ignorance of the abyssal and Southern Oceans): the historic rise started too early, has too linear a trend, and is too large. Melting of polar ice sheets at the upper limit of the Intergovernmental Panel on Climate Change estimates could close the gap, but severe limits are imposed by the observed perturbations in Earth rotation. Among possible resolutions of the enigma are: a substantial reduction from traditional estimates (including ours) of 1.5-2 mm/y global sea level rise; a substantial increase in the estimates of 20th century ocean heat storage; and a substantial change in the interpretation of the astronomic record.

  4. Sea level controls on carbonate facies associated with Mesozoic and Cenozoic hydrocarbon fields

    SciTech Connect

    Kendall, C.G.S.C. ); Alsharhan, A. ); Stoudt, D. ); Bowen, B.

    1990-05-01

    Abundant subsurface data for the Mesozoic and Cenozoic sections of the Gulf Coast of the US and the Middle East makes it possible to track the relationship of shelf carbonates and evaporites with minor clastics to eustatic sea level. Since sedimentary stratigraphy for both regions was driven by gentle tectonic subsidence punctuated by eustatic sea level variations, the major hydrocarbon fields from these areas can be classified in terms of sea level behavior at the time of the deposition of the reservoir section. With the exception of chalks, most of these carbonate hydrocarbon fields can be related to highstand system tracts and include (1) keep-up plays with sheet-like geometry formed when carbonate accumulation matched sea level rise, aggrading to form shoaling-upward cycles during sea level highstands; (2) give-up plays in which carbonate accumulation was unable to match sea level rise and catch-up plays in which carbonate accumulation initially was unable to keep pace with the sea level rise, but then aggraded to sea level forming lense-like geometry on drowned shelves downslope from carbonate margins during and following rapid sea level rises; and (3) plays with the prograded discontinuous clinoform geometry of the platform margin, formed during stillstands by carbonate accumulation that not only kept-up with the sea level rise but accumulated in a seaward direction. Source rocks for these carbonate reservoirs often formed during rapid sea level rises whereas the reservoir seals are usually shales, dense limestones and/or evaporites.

  5. Late Holocene sea level changes along the coast of Southwestern Turkey

    NASA Astrophysics Data System (ADS)

    Kızıldaǧ, Nilhan; Özdaş, Harun; Özel, Erdeniz

    2014-05-01

    A multi-disciplinary survey has been performed along the coast of southwestern Turkey in order to determine relative sea level changes during the Late Holocene. Especially, the submergence of harbour structures of the ancient coastal settlements provides noticeable evidence for eustatic sea level rise and/or tectonic subsidence. In addition, the traces of bioerosion produced by some organisms along the limestone coasts formed at mean sea level position represent a remarkable data of paleoshorelines. These traces can be found below the current sea level nowadays due to relative sea level rise. Both archaeological and biological data provide an important source on the amount and period of relative sea level rise along the coasts of southwestern Turkey-southeastern Aegean Sea. This region is under the influence of active tectonism as a result of the collision of the Arab-African and Eurasian plates. Thus, a large number of earthquakes have occurred in this zone which must have been an impact on submergence of ancient harbour structures and geomorphological formations. This area is located very important zone in terms of being tectonically active, having a large number of ancient coastal settlements, and consisting of limestone lithology. A number of submerged archaeological structures and bioerosion formations have been investigated by measuring the depths of remains with respect to the present sea level. By comparing the eustatic sea level change, current elevations and construction time of archaeological remains, which dated taking into account construction techniques and ceramic findings, we determine the amount of relative sea level change. In addition, numerous active faults have been detected by performing seismic survey. The results indicate that the vertical tectonic movement has much more effect on submergence of archaeological and geomorphological features than eustatic sea level rise. Uncovering the role of the tectonic movement and sea level changes on the

  6. Facies analysis at Triassic/Jurassic boundary: support for eustatic control of global sequence stratigraphy

    SciTech Connect

    Loughman, D.L.

    1988-02-01

    Recognition of global seismostratigraphic sequences and their eustatic interpretation has been a key geological concept of the past decade. Published criticism recently has led Exxon staff to constrain their sequence boundaries through the onshore geological record, thus placing the data base partially in the public domain. This act is a major step, since field testing of the eustatic model has been surprisingly limited, despite the latter's widespread use in interpretating basin histories. The type of field calibration required is exemplified by a comprehensive global analysis of the marine stratigraphic record from the basal Sevatian substrate (Norian) to the Semicostatum zone (Sinemurian). This 20 Ma interval was originally selected because of discrepancies between Exxon's and previous eustatic curves, and for its sound biostratigraphic control. Four key areas were studied at outcrop, in varied paleogeographic and paleotectonic settings (Peru, Nevada, northwestern Europe and pacific Canada). Fieldwork was supported by an extensive literature survey, including key areas of the eastern USSR. Interpretation involved depth assessment for each facies and the construction of bathymetric curves, which contrasts with the Exxon objective of recognizing depositional surfaces consistent with the seismostratigraphic model. A significant similarity between the 23 bathymetric curves created indicates eustatic control. The bathymetric data also constrain rates of global sea level change. Important global shallowing phases during Crickmayi zone and Angulata zone times were recognized in the study, consistent with the Exxon model. The Exxon perception of the Hettangian as a sea level lowstand is not supported and requires further discussion.

  7. Sea level change: a philosophical approach

    NASA Astrophysics Data System (ADS)

    Leinfelder, R.; Seyfried, H.

    1993-07-01

    The present Cenozoic era is an ‘icehouse’ episode characterized by a low sea level. Since the beginning of the industrial revolution, the human race has been emitting greenhouse gases, increasing the global atmospheric temperature, and causing a rise in sea level. If emissions continue to increase at the present rate, average global temperatures may rise by 1.5°C by the year 2050, accompanied by a rise of about 30 cm in sea level. However, the prediction of future climatic conditions and sea level is hampered by the difficulty in modelling the interactions between the lithosphere, kryosphere, biosphere and atmosphere; in addition, the buffering capacity of our planet is still poorly understood. As scientists cannot offer unambiguous answers to simple questions, sorcerer's apprentices fill in the gaps, presenting plans to save planet without inconveniencing us. The geological record can help us to learn about the regulation mechanisms of our planet, many of which are connected with or expressed as sea level changes. Global changes in sea level are either tectono-eustatic or glacioeustatic. Plate tectonic processes strongly control sea levels and climate in the long term. There is a strong feed-back mechanism between sea level and climate; both can influence and determine each other. Although high sea levels are a powerful climatic buffer, falling sea levels accelerate climatic accentuation, the growth of the polar ice caps and will hence amplify the drop in sea level. Important sources of fossil greenhouse gases are botanic CO2 production, CO2 released by volcanic activity, and water vapour. The latter is particularly important when the surface area of the sea increases during a rise in sea level (‘maritime greenhouse effect’). A ‘volcanogenic greenhouse effect’ (release of volcanogenic CO2) is possibly not equally important, as intense volcanic activity may take place both during icehouse episodes as well as during greenhouse episodes. The hydrosphere

  8. On Early Holocene Ice-Sheet/Sea-Level Interactions

    NASA Astrophysics Data System (ADS)

    Tornqvist, T. E.; Hijma, M.

    2011-12-01

    Early Holocene sea-level change constitutes an imperfect, yet potentially valuable analog for future sea-level rise, given the rapidly disintegrating land-based ice under climate conditions of high-latitude Northern Hemisphere warming. The associated rates of eustatic sea-level rise (cm/yr order of magnitude) fall within the range of predictions for the latter part of the next century. However, the early Holocene eustatic sea-level history is otherwise rather poorly understood. Recent impetus has been provided by new records of both relative sea-level (RSL) change and ice-sheet retreat that are sometimes difficult to reconcile in terms of timing and magnitude of change. We first summarize the state-of-the-art on early Holocene sea-level change and then identify key near-term research needs. Recent studies have identified a number of decimeter to meter-scale sea-level jumps, several of which have been linked to catastrophic drainage of proglacial Lake Agassiz and the 8.2 ka cooling event. It is increasingly clear that this occurred by means of two successive jumps, separated by up to a few centuries, and only the latter (and final) one coinciding with the 8.2 ka climate event proper. We show that a considerable research effort, including near-field, intermediate-field, and far-field localities across the globe is needed to fully understand the timing and magnitude of these sea-level jumps. Accomplishing this goal would in addition offer a unique opportunity for rigorous testing of gravitational theory and associated sea-level fingerprinting that plays a critical role in predicting future sea-level change. A more enigmatic sea-level jump that has been identified around 7.6 ka has received renewed interest both by means of new RSL data from Fennoscandia and reconstructions of Laurentide Ice Sheet retreat. However, the proposed ~5 m abrupt rise in eustatic sea level cannot be detected in relatively nearby, detailed RSL records from NW Europe, thus presenting a

  9. Global sea level rise

    SciTech Connect

    Douglas, B.C. )

    1991-04-15

    Published values for the long-term, global mean sea level rise determined from tide gauge records exhibit considerable scatter, from about 1 mm to 3 mm/yr. This disparity is not attributable to instrument error; long-term trends computed at adjacent sites often agree to within a few tenths of a millimeter per year. Instead, the differing estimates of global sea level rise appear to be in large part due to authors' using data from gauges located at convergent tectonic plate boundaries, where changes of land elevation give fictitious sea level trends. In addition, virtually all gauges undergo subsidence or uplift due to postglacial rebound (PGR) from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling PGR by the ICE-3G model of Tushingham and Peltier (1991) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. The value for mean sea level rise obtained from a global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 is 1.8 mm/yr {plus minus} 0.1. This result provides confidence that carefully selected long tide gauge records measure the same underlying trend of sea level and that many old tide gauge records are of very high quality.

  10. Evidence for sediment fan deposition on outer Texas shelf during Miocene eustatic sea level highstands

    SciTech Connect

    Riese, W.C.; Olsen, R.S.; Rosen, R.N.

    1988-02-01

    Four types of data were reviewed in an attempt to clearly define the environments of deposition for reservoir sands in the Matagorda 668 field: well log curve shapes, seismic amplitude responses, micropaleontology, and thin section sedimentary petrology. All four lines of evidence support the interpretation that these lower Miocene sands were deposited as fan complexes.

  11. Sea level variation

    NASA Technical Reports Server (NTRS)

    Douglas, Bruce C.

    1992-01-01

    Published values for the long-term, global mean sea level rise determined from tide gauge records range from about one to three mm per year. The scatter of the estimates appears to arise largely from the use of data from gauges located at convergent tectonic plate boundaries where changes of land elevation give fictitious sea level trends, and the effects of large interdecadal and longer sea level variations on short (less than 50+ years) or sappy records. In addition, virtually all gauges undergo subsidence or uplift due to isostatic rebound from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling rebound by the ICE-3G model of Tushingham and Peltier (1990) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. A global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 yields the global sea level rise value 1.8 mm/year +/- 0.1. Greenhouse warming scenarios commonly forecast an additional acceleration of global sea level in the next 5 or 6+ decades in the range 0.1-0.2 mm/yr2. Because of the large power at low frequencies in the sea level spectrum, very long tide gauge records (75 years minimum) have been examined for past apparent sea level acceleration. For the 80-year period 1905-1985, 23 essentially complete tide gauge records in 10 geographic groups are available for analysis. These yielded the apparent global acceleration -0.011 (+/- 0.012) mm/yr2. A larger, less uniform set of 37 records in the same 10 groups with 92 years average length covering the 141 years from 1850-1991 gave 0.001 (+/- 0.008) mm/yr2. Thus there is no evidence for an apparent acceleration in the past 100+ years that is significant either statistically, or in comparison to values associated with global warming. Unfortunately, the large interdecadal fluctuations of sea level severely affect

  12. History of coral reefs and sea level

    SciTech Connect

    Fairbridge, R.W.

    1985-01-01

    Charles Darwin proposed crustal subsidence for atoll growth, on the Beagle, between England and Brazil, before even seeing a coral reef, on the basis of charts and discussions with Captain Fitzroy. Relative change of sea level due to crustal movements was then well-accepted from evidence of raised strandlines in Scandinavia and Scotland and sunken forests in England. Darwin added global change of sea level (tectonoeustasy) caused by remote tectonic activity, as explained by Robert Chambers (1848, p. 319). The glacioeustasy concept was mooted soon afterwards, though the term itself came later. When Suess in 1888 proposed eustatic change, he had in mind Archimedian displacement of water by sediment or lava accumulation on the sea floor. Integrated ideas of reef development also came in the 20th century. The powerful arguments against Darwin were led by Murray with his solution hypothesis, which can not be judged as good observation but from a narrow viewpoint. The Royal Society reef borings at Funafuti were heroic but at the same time misread. Subsequently came isotopic geochemistry, absolute dating, the Milankovitch insolation theory, and plate tectonics. And much more field work. The result is an integrated reef growth theory.

  13. Sea level change

    SciTech Connect

    Meier, M.F.

    1996-12-31

    The IPCC (Intergovernmental Panel on Climate Change) 1995 Scientific Assessment, Chapter 7. Sea Level Change, presents a modest revision of the similar chapter in the 1990 Assessment. Principal conclusions on observed sea-level change and the principal terms in the sea-level equation (ocean thermal expansion, glaciers, ice sheets, and land hydrology), including our knowledge of the present-day (defined as the 20th Century) components of sea-level rise, and projections of these for the future, are presented here. Some of the interesting glaciological problems which are involved in these studies are discussed in more detail. The emphasis here is on trends over decades to a century, not on shorter variations nor on those of the geologic past. Unfortunately, some of the IPCC projections had not been agreed at the time of writing of this paper, and these projections will not be given here. 15 refs., 2 figs.

  14. Contemporary sea level rise.

    PubMed

    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.

  15. Projecting future sea level

    USGS Publications Warehouse

    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

  16. Paleoshoreline record of relative Holocene sea levels on Pacific islands

    NASA Astrophysics Data System (ADS)

    Dickinson, William R.

    2001-11-01

    Understanding the history of relative Holocene sea levels on Pacific islands is important for constraining fundamental geodynamic theories, interpreting the environments of early human occupation sites, and forecasting future environmental conditions on the islands. An observational paleoshoreline record is provided by emergent paleoshoreline indicators formed at higher relative sea levels, hence standing at higher elevations than modern counterparts. Emergent paleoshoreline notches in limestone seacliffs record paleo-high-tide levels and emergent paleoreef flats record paleo-low-tide levels, whereas emergent paleobeachrock locally records paleo-intertidal levels. Both paleonotches and paleoreefs occur along the coasts of high-standing islands exposing volcanic bedrock and uplifted reef complexes, but low-lying coralline atolls lack sufficient relief to preserve paleonotches. Controls on relative Holocene sea level include global eustatic and regional hydro-isostatic changes in ambient sea level relative to island landmasses, and shifts in the elevations of islands relative to sea level caused by thermal subsidence of the oceanic lithosphere or thermally rejuvenated loci of hotspot volcanism, by flexure of the lithosphere under the load of growing volcanic edifices (Hawaii, Samoa, Society Islands), by arching of the lithosphere over trench forebulges (Loyalty Islands, Niue, Bellona-Rennell), and by tectonism within forearc belts between active volcanic chains and trenches (Mariana Islands, Tonga, Vanuatu). The dominant pattern of relative sea-level change, where not overprinted by local tectonism or lithospheric flexure, was a uniform early Holocene rise in eustatic sea level followed by a regionally variable late Holocene hydro-isostatic drawdown in sea level. The resultant was a mid-Holocene highstand in relative sea level that affected the development of shoreline morphology throughout the tropical Pacific Ocean. The earliest human migrations into intra

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

    SciTech Connect

    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.

  18. Caribbean Sea Level Network

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    Over the past 500 years almost 100 tsunamis have been observed in the Caribbean and Western Atlantic, with at least 3510 people having lost their lives to this hazard since 1842. Furthermore, with the dramatic increase in population and infrastructure along the Caribbean coasts, today, millions of coastal residents, workers and visitors are vulnerable to tsunamis. The UNESCO IOC Intergovernmental Coordination Group for Tsunamis and other Coastal Hazards for the Caribbean and Adjacent Regions (CARIBE EWS) was established in 2005 to coordinate and advance the regional tsunami warning system. The CARIBE EWS focuses on four areas/working groups: (1) Monitoring and Warning, (2) Hazard and Risk Assessment, (3) Communication and (4) Education, Preparedness and Readiness. The sea level monitoring component is under Working Group 1. Although in the current system, it's the seismic data and information that generate the initial tsunami bulletins, it is the data from deep ocean buoys (DARTS) and the coastal sea level gauges that are critical for the actual detection and forecasting of tsunamis impact. Despite multiple efforts and investments in the installation of sea level stations in the region, in 2004 there were only a handful of sea level stations operational in the region (Puerto Rico, US Virgin Islands, Bermuda, Bahamas). Over the past 5 years there has been a steady increase in the number of stations operating in the Caribbean region. As of mid 2012 there were 7 DARTS and 37 coastal gauges with additional ones being installed or funded. In order to reach the goal of 100 operational coastal sea level stations in the Caribbean, the CARIBE EWS recognizes also the importance of maintaining the current stations. For this, a trained workforce in the region for the installation, operation and data analysis and quality control is considered to be critical. Since 2008, three training courses have been offered to the sea level station operators and data analysts. Other

  19. Early humans and rapidly changing holocene sea levels in the Queen Charlotte Islands - Hecate Strait, British Columbia, Canada

    SciTech Connect

    Josenhans, H.; Fedje, D.; Pienitz, R.; Southon, J.

    1997-07-04

    Marine cores from the continental shelf edge of British Columbia (Canada) demonstrate that sea level at the shelf edge was 153 meters below present 14,000 calendar years ago and more than 30 meters lower than the maximum eustatic low of -120 meters. Dated artifacts, including stone tools, indicate that humans occupied this region by at least 10,200 calendar years before present (B.P.). Local sea level rose rapidly (5 centimeters per year) during the period of early human occupation as a result of eustatic sea-level rise and glacio-isostatic forebulge movement. This shelf edge site was first elevated and then subsided. The exposed shelf edge was available for human occupation and may have served as a migration route during times of lowered sea levels between 13,500 and 9500 {sup 14}C years B.P. 34 refs., 6 figs., 1 tab.

  20. Understanding Sea Level Changes

    NASA Technical Reports Server (NTRS)

    Chao, Benjamin F.

    2004-01-01

    Today more than 100 million people worldwide live on coastlines within one meter of mean sea level; any short-term or long-term sea level change relative to vertical ground motion is of great societal and economic concern. As palm-environment and historical data have clearly indicated the existence and prevalence of such changes in the past, new scientific information regarding to the nature and causes and a prediction capability are of utmost importance for the future. The 10-20 cm global sea-level rise recorded over the last century has been broadly attributed to two effects: (1) the steric effect (thermal expansion and salinity-density compensation of sea water) following global climate; (2) mass-budget changes due to a number of competing geophysical and hydrological processes in the Earth-atmosphere-hydrosphere-cryosphere system, including water exchange from polar ice sheets and mountain glaciers to the ocean, atmospheric water vapor and land hydrological variations, and anthropogenic effects such as water impoundment in artificial reservoirs and extraction of groundwater, all superimposed on the vertical motions of solid Earth due to tectonics, rebound of the mantle from past and present deglaciation, and other local ground motions. As remote-sensing tools, a number of space geodetic measurements of sea surface topography (e.g., TOPEX/Poseidon, Jason), ice mass (e.g., ICESat), time-variable gravity (e.g. GRACE), and ground motions (SLR, VLBI, GPS, InSAR, Laser altimetry, etc.) become directly relevant. Understanding sea level changes "anywhere, anytime" in a well-defined terrestrial reference frame in terms of climate change and interactions among ice masses, oceans, and the solid Earth, and being able to predict them, emerge as one of the scientific challenges in the Solid Earth Science Working Group (SESWG, 2003) conclusions.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  2. Antarctic glacio-eustatic contributions to late Miocene Mediterranean desiccation and reflooding.

    PubMed

    Ohneiser, Christian; Florindo, Fabio; Stocchi, Paolo; Roberts, Andrew P; DeConto, Robert M; Pollard, David

    2015-11-10

    The Messinian Salinity Crisis (MSC) was a marked late Neogene oceanographic event during which the Mediterranean Sea evaporated. Its causes remain unresolved, with tectonic restrictions to the Atlantic Ocean or glacio-eustatic restriction of flow during sea-level lowstands, or a mixture of the two mechanisms, being proposed. Here we present the first direct geological evidence of Antarctic ice-sheet (AIS) expansion at the MSC onset and use a δ(18)O record to model relative sea-level changes. Antarctic sedimentary successions indicate AIS expansion at 6 Ma coincident with major MSC desiccation; relative sea-level modelling indicates a prolonged ∼50 m lowstand at the Strait of Gibraltar, which resulted from AIS expansion and local evaporation of sea water in concert with evaporite precipitation that caused lithospheric deformation. Our results reconcile MSC events and demonstrate that desiccation and refilling were timed by the interplay between glacio-eustatic sea-level variations, glacial isostatic adjustment and mantle deformation in response to changing water and evaporite loads.

  3. Antarctic glacio-eustatic contributions to late Miocene Mediterranean desiccation and reflooding

    PubMed Central

    Ohneiser, Christian; Florindo, Fabio; Stocchi, Paolo; Roberts, Andrew P.; DeConto, Robert M.; Pollard, David

    2015-01-01

    The Messinian Salinity Crisis (MSC) was a marked late Neogene oceanographic event during which the Mediterranean Sea evaporated. Its causes remain unresolved, with tectonic restrictions to the Atlantic Ocean or glacio-eustatic restriction of flow during sea-level lowstands, or a mixture of the two mechanisms, being proposed. Here we present the first direct geological evidence of Antarctic ice-sheet (AIS) expansion at the MSC onset and use a δ18O record to model relative sea-level changes. Antarctic sedimentary successions indicate AIS expansion at 6 Ma coincident with major MSC desiccation; relative sea-level modelling indicates a prolonged ∼50 m lowstand at the Strait of Gibraltar, which resulted from AIS expansion and local evaporation of sea water in concert with evaporite precipitation that caused lithospheric deformation. Our results reconcile MSC events and demonstrate that desiccation and refilling were timed by the interplay between glacio-eustatic sea-level variations, glacial isostatic adjustment and mantle deformation in response to changing water and evaporite loads. PMID:26556503

  4. Late Quaternary sea-level changes of the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Lokier, Stephen W.; Bateman, Mark D.; Larkin, Nigel R.; Rye, Philip; Stewart, John R.

    2015-07-01

    Late Quaternary reflooding of the Persian Gulf climaxed with the mid-Holocene highstand previously variously dated between 6 and 3.4 ka. Examination of the stratigraphic and paleoenvironmental context of a mid-Holocene whale beaching allows us to accurately constrain the timing of the transgressive, highstand and regressive phases of the mid- to late Holocene sea-level highstand in the Persian Gulf. Mid-Holocene transgression of the Gulf surpassed today's sea level by 7100-6890 cal yr BP, attaining a highstand of > 1 m above current sea level shortly after 5290-4570 cal yr BP before falling back to current levels by 1440-1170 cal yr BP. The cetacean beached into an intertidal hardground pond during the transgressive phase (5300-4960 cal yr BP) with continued transgression interring the skeleton in shallow-subtidal sediments. Subsequent relative sea-level fall produced a forced regression with consequent progradation of the coastal system. These new ages refine previously reported timings for the mid- to late Holocene sea-level highstand published for other regions. By so doing, they allow us to constrain the timing of this correlatable global eustatic event more accurately.

  5. Quaternary climates and sea levels of the u.s. Atlantic coastal plain.

    PubMed

    Cronin, T M; Szabo, B J; Ager, T A; Hazel, J E; Owens, J P

    1981-01-16

    Uranium-series dating of corals from marine deposits of the U.S. Atlantic Coastal Plain coupled with paleoclimatic reconstructions based on ostracode (marine) and pollen (continent) data document at least five relatively warm intervals during the last 500,000 years. On the basis of multiple paleoenvironmental criteria, we determined relative sea level positions during the warm intervals, relative to present mean sea level, were 7 +/- 5 meters at 188,000 years ago, 7.5 +/- 1.5 meters at 120,000 years ago, 6.5 +/- 3.5 meters at 94,000 years ago, and 7 +/- 3 meters at 72,000 years ago. The composite sea level chronology for the Atlantic Coastal Plain is inconsistent with independent estimates of eustatic sea level positions during interglacial intervals of the last 200,000 years. Hydroisostatic adjustment from glacial-interglacial sea level fluctuations, lithospheric flexure, and isostatic uplift from sediment unloading due to erosion provide possible mechanisms to account for the discrepancies. Alternatively, current eustatic sea level estimates for the middle and late Quaternary may require revision.

  6. Sea-level rise in New Jersey over the past 5000 years: Implications to anthropogenic changes

    USGS Publications Warehouse

    Miller, Kenneth G.; Sugarman, Peter J.; Browning, James V.; Horton, Benjamin P.; Stanley, Alissa; Kahn, Alicia; Uptegrove, Jane; Aucott, Michael

    2009-01-01

    We present a mid to late Holocene sea-level record derived from drilling the New Jersey coast that shows a relatively constant rise of 1.8??mm/yr from ~ 5000 to 500 calibrated calendar years before present (yrBP). This contrasts with previous New Jersey estimates that showed only 0.5??mm/yr rise since 2000??yrBP. Comparison with other Mid-Atlantic sea-level records (Delaware to southern New England) indicates surprising uniformity considering different proximities to the peripheral bulge of the Laurentide ice sheet, with a relative rise throughout the region of ~ 1.7-1.9??mm/yr since ~ 5000??yrBP. This regional sea-level rise includes both: 1) global sea-level (eustatic) rise; and 2) far-field geoidal subsidence (estimated as ~ 0.8-1.4??mm/yr today) due to removal of the Laurentide ice sheet and water loading. Correcting for geoidal subsidence, the U.S. east coast records suggest a global sea-level (eustatic) rise of ~ 0.4-1.0??mm/yr (with a best estimate of 0.7 ?? 0.3??mm/yr) since 5000??yrBP. Comparison with other records provides a best estimate of pre-anthropogenic global sea-level rise of < 1.0??mm/yr from 5000 until ~ 200??yrBP. Tide gauge data indicate a 20th century rate of eustatic rise of 1.8??mm/yr, whereas both tide gauge and satellite data suggest an increase in the rate of rise to ~ 3.3??mm/yr from 1993-2006 AD. This indicates that the modern rise (~ 3.3??mm/yr) is significantly higher than the pre-anthropogenic rise (0.7 ?? 0.3??mm/yr). ?? 2008 Elsevier B.V. All rights reserved.

  7. Mediterranean Sea level variations during the Messinian salinity crisis

    NASA Astrophysics Data System (ADS)

    Gargani, Julien; Rigollet, Christophe

    2007-05-01

    The Mediterranean Basin has not always been connected to the Atlantic Ocean. During the Messinian salinity crisis (MSC), the Mediterranean Sea became progressively isolated by a complex combination of tectonic and glacio-eustatic processes. When isolated, the Mediterranean water level depends on the hydrological flux and is expected to vary significantly. The amplitude and number of large water level fluctuations in the isolated Mediterranean is still controversial, despite numerous geological investigations. The observation of 3-5 surfaces of erosion in the Nile delta (Eastern Basin) provides new elements for understanding the dynamics of the MSC. Our model demonstrates that numerous water level falls of short duration may explain the preservation of a discontinuous river profile at ~-500 m and ~-1500 m in the Western Basin, as well as the existence of deep surfaces of erosion in the Eastern Basin.

  8. Depositional facies and eustatic effects in Upper Cretaceous (Maastrichtian) Ripley Formation, central and eastern Alabama

    SciTech Connect

    Skotnicki, M.C.; King, D.T. Jr. )

    1989-09-01

    In eastern and central Alabama, the Upper Cretaceous Ripley Formation (40-175 m thick) is comprised of five depositional facies. Facies 1 (barrier-island shoreface and tidal-inlet fill) is a medium to coarse, intraclastic quartzose sand that is planar and trough cross-stratified and has abundant Ophiomorpha traces. Facies 2 (back-barrier lagoon or marsh) is a bioturbated, micaceous, carbonaceous silt that contains macerated plant debris and bivalve molds and impressions. Interbedded with facies 2 is facies 3 (storm-washover deposits), a hummocky cross-stratified, micaceous fine sand. Facies 4 (back-barrier tidal flat) is a micaceous silty clay lacking body fossils and plant debris. Facies 5 (lower shoreface) is a glauconitic, clayey and micaceous, fine to medium sand that is highly bioturbated and commonly has abundant marine macrofauna. The Ripley is divided into two genetic packages of facies; the genetic packages are bounded by stratigraphic breaks or discontinuities. The package-bounding breaks are correlated biostratigraphically with discrete third-order eustatic drops on the world sea level curve. The basal Ripley break is correlated with the end of Campanian (about 74 Ma) eustatic drop, and the middle Ripley break (separating the two genetic packages) marks the mid-Maastrichtian (71 Ma) sea level drop. The basal and middle Ripley breaks are low-relief surfaces marked by sharp facies discontinuities (correlatable across 130 km) and terminal coarsening-upward cycles (5 m thick); the estimated eustatic sea level fall in both instances was about 50 m. The break at the top of the Ripley has 70 m of erosional relief and a bone bed up to 80 cm thick. This break represents a late Maastrichtian (about 68 Ma) sea level fall estimated to have been nearly 95 m. Facies of the superjacent Prairie Bluff Chalk and Providence Sand overlie the erosional surface.

  9. Future sea-level rise in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Galassi, Gaia; Spada, Giorgio

    2014-05-01

    Secular sea level variations in the Mediterranean Sea are the result of a number of processes characterized by distinct time scales and spatial patterns. Here we predict the future sea level variations in the Mediterranean Sea to year 2050 combining the contributions from terrestrial ice melt (TIM), glacial isostatic adjustment (GIA), and the ocean response (OR) that includes the thermal expansion and the ocean circulation contributions. The three contributions are characterized by comparable magnitudes but distinctly different sea-level fingerprints across the Mediterranean basin. The TIM component of future sea-level rise is taken from Spada et al. (2013) and it is mainly driven by the melt of small glaciers and ice caps and by the dynamic ice loss from Antarctica. The sea-level fingerprint associated with GIA is studied using two distinct models available from the literature: ICE-5G(VM2) (Peltier, 2004) and the ice model progressively developed at the Research School of Earth Sciences (RSES) of the National Australian University (KL05) (see Fleming and Lambeck, 2004 and references therein). Both the GIA and the TIM sea-level predictions have been obtained with the aid of the SELEN program (Spada and Stocchi, 2007). The spatially-averaged OR component, which includes thermosteric and halosteric sea-level variations, recently obtained using a regional coupled ocean-atmosphere model (Carillo et al., 2012), vary between 2 and 7 cm according to scenarios adopted (EA1B and EA1B2, see Meehl at al., 2007). Since the sea-level variations associated with TIM mainly result from the gravitational interactions between the cryosphere components, the oceans and the solid Earth, and long-wavelength rotational variations, they are characterized by a very smooth global pattern and by a marked zonal symmetry reflecting the dipole geometry of the ice sources. Since the Mediterranean Sea is located in the intermediate far-field of major ice sources, TIM sea-level changes have sub-eustatic

  10. Holocene Relative Sea-Level Changes from Near-, Intermediate-, and Far-Field Locations

    NASA Astrophysics Data System (ADS)

    Walker, J. S.; Khan, N.; Shaw, T.; Ashe, E.; Vacchi, M.; Peltier, W. R.; Kopp, R. E.; Horton, B.

    2015-12-01

    Holocene relative sea-level (RSL) records exhibit spatial and temporal variability that arises mainly from the interaction of eustatic (land ice volume and thermal expansion) and isostatic (glacio- and hydro-) factors. We fit RSL histories from near-, intermediate-, and far-field locations with noisy-input Gaussian process models to assess rates of RSL change from selected study areas. Records from near-field regions (e.g., Antarctica, Greenland, Canada, Sweden, and Scotland) reveal a complex pattern of RSL fall from a maximum marine limit due to the net effect of eustatic sea-level rise and glacial-isostatic uplift with rates of RSL fall as great as -69 ± 9 m/ka. Intermediate-field regions (e.g., mid-Atlantic and Pacific coasts of the United States, Netherlands, Southern France, St. Croix) display variable rates of RSL rise from the cumulative effect of isostatic and eustatic factors. Fast rates of RSL rise (up to 10 ± 1 m/ka) are found in the early Holocene in regions near the center of forebulge collapse. Far-field RSL records exhibit a mid-Holocene highstand, the timing (between 8 and 4 ka) and magnitude (between <1 and 6 m) of which varies across South America, Africa, Asia and Australia regions.

  11. Late Pleistocene Sea Level Stack

    NASA Astrophysics Data System (ADS)

    Spratt, R. M.; Lisiecki, L. E.

    2014-12-01

    Sea level reconstructions have been created using wide variety of proxies and models. The accuracy of individual sea level reconstructions is limited by measurement, noise, local variations in salinity and temperature, and the assumptions particular to each reconstruction. To address these limitations, we have created a sea level stack (average) which increases the signal-to-noise ratio of sea level estimates by combining 5-7 sea level reconstructions over the last 800 kyr. Principal Component analysis (PCA) of seven sea level records from 0-430 kyr ago shows that 82% of the variance in these records is explained by their first principal component (i.e., the stack). Additionally, a stack of just the 5 longer records that extends to 800 kyr closely matches the timing and amplitude of our seven-record mean. We find that the mean sea level estimate for Marine Isotope Stage (MIS) 5e is 0-4 m above modern, and that the standard deviation of individual estimates is 11 m. Mean sea level estimates for MIS 11 are 12-16 m above modern with a standard deviation of 30 m. Due to the large variability between individual reconstructions, our sea level stack may provide more robust sea level estimates than any single technique.

  12. Sea level in Roman time in the Central Mediterranean and implications for recent change

    NASA Astrophysics Data System (ADS)

    Lambeck, Kurt; Anzidei, Marco; Antonioli, Fabrizio; Benini, Alessandra; Esposito, Alessandra

    2004-08-01

    Instrumental records indicate that ocean volumes during the 20th century have increased so as to raise eustatic sea level by ˜1-2 mm/year and the few available records suggest that this is higher than for the previous century. Geological data indicate that ocean volumes have increased since the main phase of deglaciation about 7000 years ago but whether this continued into the recent past remains unclear. Yet, this is important for establishing whether the recent rise is associated with global warming or is part of a longer duration non-anthropogenic signal. Here, we present results for sea-level change in the central Mediterranean basin for the Roman Period using new archaeological evidence. These data provide a precise measure of local sea level of -1.35±0.07 m at 2000 years ago. Part of this change is the result of ongoing glacio-hydro isostatic adjustment of the crust subsequent to the last deglaciation. When corrected for this, using geologically constrained model predictions, the change in eustatic sea level since the Roman Period is -0.13±0.09 m. A comparison with tide-gauge records from nearby locations and with geologically constrained model predictions of the glacio-isostatic contributions establishes that the onset of modern sea-level rise occurred in recent time at ˜100±53 years before present.

  13. Holocene sea level variations on the basis of integration of independent data sets

    SciTech Connect

    Sahagian, D.; Berkman, P. . Dept. of Geological Sciences and Byrd Polar Research Center)

    1992-01-01

    Variations in sea level through earth history have occurred at a wide variety of time scales. Sea level researchers have attacked the problem of measuring these sea level changes through a variety of approaches, each relevant only to the time scale in question, and usually only relevant to the specific locality from which a specific type of data are derived. There is a plethora of different data types that can and have been used (locally) for the measurement of Holocene sea level variations. The problem of merging different data sets for the purpose of constructing a global eustatic sea level curve for the Holocene has not previously been adequately addressed. The authors direct the efforts to that end. Numerous studies have been published regarding Holocene sea level changes. These have involved exposed fossil reef elevations, elevation of tidal deltas, elevation of depth of intertidal peat deposits, caves, tree rings, ice cores, moraines, eolian dune ridges, marine-cut terrace elevations, marine carbonate species, tide gauges, and lake level variations. Each of these data sets is based on particular set of assumptions, and is valid for a specific set of environments. In order to obtain the most accurate possible sea level curve for the Holocene, these data sets must be merged so that local and other influences can be filtered out of each data set. Since each data set involves very different measurements, each is scaled in order to define the sensitivity of the proxy measurement parameter to sea level, including error bounds. This effectively determines the temporal and spatial resolution of each data set. The level of independence of data sets is also quantified, in order to rule out the possibility of a common non-eustatic factor affecting more than one variety of data. The Holocene sea level curve is considered to be independent of other factors affecting the proxy data, and is taken to represent the relation between global ocean water and basin volumes.

  14. Upper Cretaceous sequences and sea-level history, New Jersey Coastal Plain

    USGS Publications Warehouse

    Miller, K.G.; Sugarman, P.J.; Browning, J.V.; Kominz, M.A.; Olsson, R.K.; Feigenson, M.D.; Hernandez, J.C.

    2004-01-01

    We developed a Late Cretaceous sealevel estimate from Upper Cretaceous sequences at Bass River and Ancora, New Jersey (ODP [Ocean Drilling Program] Leg 174AX). We dated 11-14 sequences by integrating Sr isotope and biostratigraphy (age resolution ??0.5 m.y.) and then estimated paleoenvironmental changes within the sequences from lithofacies and biofacies analyses. Sequences generally shallow upsection from middle-neritic to inner-neritic paleodepths, as shown by the transition from thin basal glauconite shelf sands (transgressive systems tracts [TST]), to medial-prodelta silty clays (highstand systems tracts [HST]), and finally to upper-delta-front quartz sands (HST). Sea-level estimates obtained by backstripping (accounting for paleodepth variations, sediment loading, compaction, and basin subsidence) indicate that large (>25 m) and rapid (???1 m.y.) sea-level variations occurred during the Late Cretaceous greenhouse world. The fact that the timing of Upper Cretaceous sequence boundaries in New Jersey is similar to the sea-level lowering records of Exxon Production Research Company (EPR), northwest European sections, and Russian platform outcrops points to a global cause. Because backstripping, seismicity, seismic stratigraphic data, and sediment-distribution patterns all indicate minimal tectonic effects on the New Jersey Coastal Plain, we interpret that we have isolated a eustatic signature. The only known mechanism that can explain such global changes-glacio-eustasy-is consistent with foraminiferal ??18O data. Either continental ice sheets paced sea-level changes during the Late Cretaceous, or our understanding of causal mechanisms for global sea-level change is fundamentally flawed. Comparison of our eustatic history with published ice-sheet models and Milankovitch predictions suggests that small (5-10 ?? 106 km3), ephemeral, and areally restricted Antarctic ice sheets paced the Late Cretaceous global sea-level change. New Jersey and Russian eustatic estimates

  15. Late Holocene sea level variability and Atlantic Meridional Overturning Circulation

    USGS Publications Warehouse

    Cronin, Thomas M.; Farmer, Jesse R.; Marzen, R. E.; Thomas, E.; Varekamp, J.C.

    2014-01-01

    Pre-twentieth century sea level (SL) variability remains poorly understood due to limits of tide gauge records, low temporal resolution of tidal marsh records, and regional anomalies caused by dynamic ocean processes, notably multidecadal changes in Atlantic Meridional Overturning Circulation (AMOC). We examined SL and AMOC variability along the eastern United States over the last 2000 years, using a SL curve constructed from proxy sea surface temperature (SST) records from Chesapeake Bay, and twentieth century SL-sea surface temperature (SST) relations derived from tide gauges and instrumental SST. The SL curve shows multidecadal-scale variability (20–30 years) during the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA), as well as the twentieth century. During these SL oscillations, short-term rates ranged from 2 to 4 mm yr−1, roughly similar to those of the last few decades. These oscillations likely represent internal modes of climate variability related to AMOC variability and originating at high latitudes, although the exact mechanisms remain unclear. Results imply that dynamic ocean changes, in addition to thermosteric, glacio-eustatic, or glacio-isostatic processes are an inherent part of SL variability in coastal regions, even during millennial-scale climate oscillations such as the MCA and LIA and should be factored into efforts that use tide gauges and tidal marsh sediments to understand global sea level rise.

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

    NASA Astrophysics Data System (ADS)

    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

  17. Early-mid-Cretaceous evolution in Tethyan reef communities and sea level

    SciTech Connect

    Scott, R.W.

    1988-01-01

    The replacement of corals by rudists in Early Cretaceous reefal communities spanned a 30-m.y. period when sea level rose and drowned continental shelves. During this time corals formed communities in the deeper parts of reefs and rudists occupied the shallow, high-energy habitats. By Aptian time rudists dominated reefs that fringed interior shelf basins and corals formed reefs with rudists on the outer shelf margins. By late Albian coral communities had virtually disappeared, presumably because of complex environmental changes and cycles of organic productivity. Two important events of eustatic sea level rise are represented by unconformities separating carbonate depositional sequences on the Arabian platform that correlate with sequence boundaries on the Gulf Coast platform. Graphic correlation techniques test the synchroneity of these events. A composite standard time scale dates these sea level rises at 115.8 Ma and 94.6 Ma; a third, intra-Albian event at 104.3 Ma is present in many places and may also be eustatic. Associated with these sea level rises were apparent changes in ocean water chemistry as evidenced by changes in isotopes and trace elements, where diagenetic effects can be discounted. During this time the climate became more humid and atmospheric CO/sub 2/ increased. The concomitant environmental changes in the oceanic conditions presumably stressed the deeper coral communities on reefs. The emergence of rudists as reef contributors had a profound effect on Late Cretaceous depositional conditions and the development of hydrocarbon reservoirs.

  18. Early-mid-Cretaceous evolution in Tethyan reef communities and sea level

    SciTech Connect

    Scott, R.W.

    1988-02-01

    The replacement of corals by rudists in Early Cretaceous reefal communities spanned a 30-m.y. period when sea level rose and drowned continental shelves. During this time corals formed communities in the deeper parts of reefs and rudists occupied the shallow, high-energy habitats. By Aptian time rudists dominated reefs that fringed interior shelf basins and corals formed reefs with rudists on the outer shelf margins. By late Albian coral communities had virtually disappeared, presumably because of complex environmental changes and cycles of organic productivity. Two important events of eustatic sea level rise are represented by unconformities separating carbonate depositional sequences on the Arabian platform that correlate with sequence boundaries on the Gulf Coast platform. Graphic correlation techniques test the synchroneity of these events. A composite standard time scale dates these sea level rises at 115.8 Ma and 94.6 Ma; a third, intra-Albian event at 104.3 Ma is present in many places and may also be eustatic. Associated with these sea level rises were apparent changes in ocean water chemistry as evidenced by changes in isotopes and trace elements, where diagenetic effects can be discounted. During this time the climate became more humid and atmospheric CO/sub 2/ increased. The concomitant environmental changes in the oceanic conditions presumably stressed the deeper coral communities on reefs. The emergence of rudists as reef contributors had a profound effect on Late Cretaceous depositional conditions and the development of hydrocarbon reservoirs.

  19. Mississippi delta-lobe switching during holocene eustatic fluctuations

    SciTech Connect

    Fairbridge, R.W.; Lowrie, A.

    1988-01-01

    Delta formation plays an integral role in basin development at a passive continental margin, with depocenters under eustatic control shifting alternately landward and seaward during time frames ranging from decades to 10/sup 8/ years. The classic Gilbert delta model was hydraulic and climatogenetic, based on his Lake Bonneville experience. The authors challenge the Gilbert model applied to the Mississippi delta, in that the model requires synchronous climatic fluctuations over a 3,327,000 km/sup 2/ drainage basin. From the Mississippi delta apex to the Gulf of Mexico, the dynamic gradient is 1:55,000, although the direct slope, over approx. = 110 km, is 1:20,000. Holocene sea levels fluctuated 1-2 m. During cool periods, as in the Little Ice Age (Maximum AD 1650-1750), sea level dropped 0.5-1 m, changing the dynamic and direct gradients to 1:50,000 and 1:18,000, respectively. During warm periods, as in the Viking times 1,000 years ago, sea level rose 0.5-0.6 m, changing the gradients to 1:78,000 and 1:28,000, respectively. Such large gradient changes increase the opportunities for river entrenchment and stream stability during cool periods and delta-lobe switching during warm periods. Available radiometric dates for the 16 individual delta lobes developed since 6,000 Ma concentrated in six delta complexes and revealed that the 1,000-1,500 yr delta-switching cyclicity roughly coincides with concurrent glacial advances and retreats. C/sub 14/ dates of peats indicate regressions, comparable to those of the North SEa. Gaps in peat-derived dates indicate transgressions.

  20. A fractal analysis of quaternary, Cenozoic-Mesozoic, and Late Pennsylvanian sea level changes

    NASA Technical Reports Server (NTRS)

    Hsui, Albert T.; Rust, Kelly A.; Klein, George D.

    1993-01-01

    Sea level changes are related to both climatic variations and tectonic movements. The fractal dimensions of several sea level curves were compared to a modern climatic fractal dimension of 1.26 established for annual precipitation records. A similar fractal dimension (1.22) based on delta(O-18/O-16) in deep-sea sediments has been suggested to characterize climatic change during the past 2 m.y. Our analysis indicates that sea level changes over the past 150,000 to 250,000 years also exhibit comparable fractal dimensions. Sea level changes for periods longer than about 30 m.y. are found to produce fractal dimensions closer to unity and Missourian (Late Pennsylvanian) sea level changes yield a fractal dimension of 1.41. The fact that these sea level curves all possess fractal dimensions less than 1.5 indicates that sea level changes exhibit nonperiodic, long-run persistence. The different fractal dimensions calculated for the various time periods could be the result of a characteristic overprinting of the sediment recored by prevailing processes during deposition. For example, during the Quaternary, glacio-eustatic sea level changes correlate well with the present climatic signature. During the Missourian, however, mechanisms such as plate reorganization may have dominated, resulting in a significantly different fractal dimension.

  1. Paleochannels indicating wet climate and lack of response to lower sea level, southeast Georgia

    NASA Astrophysics Data System (ADS)

    Leigh, David S.; Feeney, Thomas P.

    1995-08-01

    Large meandering paleochannels on the flood plain of the middle Ogeechee River in southeast Georgia represent wet paleoclimate during late Pleistocene and early Holocene time and show no indication of downcutting in response to eustatically lower sea level. Radiocarbon dates indicate that the paleomeanders were active at ˜31 28 ka and ˜8.5 4.5 ka. Bivariate regression models that correlate modern channel dimensions to the discharge of low-magnitude floods (1 5 yr recurrence interval) indicate that paleodischarge of floods during those times was at least double that of modern floods, thus suggesting a wetter paleoclimate. These data corroborate independent studies of pollen and paleoclimate simulations that indicate wet early to middle Holocene (9 3 ka) conditions that were characterized by intensified monsoonal circulation. Paleoclimate conditions at ˜31 28 ka are less well known. Our analysis of the middle Ogeechee River flood plain indicates the absence of base-level response (downcutting) to eustatic sea-level lowering because the beds of the paleochannels are at approximately the same elevation as the bed of the modern channel. This supports recent arguments that the geomorphic response of coastal-plain streams to sea-level lowering is most apparent in deltaic and shelf environments and may not be recognized very far upstream from the coast.

  2. Sea Level Rise in Tuvalu

    NASA Astrophysics Data System (ADS)

    Lin, C. C.; Ho, C. R.; Cheng, Y. H.

    2012-04-01

    Most people, especially for Pacific Islanders, are aware of the sea level change which may caused by many factors, but no of them has deeper sensation of flooding than Tuvaluan. Tuvalu, a coral country, consists of nine low-lying islands in the central Pacific between the latitudes of 5 and 10 degrees south, has the average elevation of 2 meters (South Pacific Sea Level and Climate Monitoring Project, SPSLCMP report, 2006) up to sea level. Meanwhile, the maximum sea level recorded was 3.44m on February 28th 2006 that damaged Tuvaluan's property badly. Local people called the flooding water oozes up out of the ground "King Tide", that happened almost once or twice a year, which destroyed the plant, polluted their fresh water, and forced them to colonize to some other countries. The predictable but uncontrollable king tide had been observed for a long time by SPSLCMP, but some of the uncertainties which intensify the sea level rise need to be analyzed furthermore. In this study, a span of 18 years of tide gauge data accessed from Sea Level Fine Resolution Acoustic Measuring Equipment (SEAFRAME) are compared with the satellite altimeter data accessed from Archiving Validation and Interpretation of Satellite Data in Oceanography (AVISO). All above are processed under the limitation of same time and spatial range. The outcome revealed a 9.26cm difference between both. After the tide gauge data shifted to the same base as altimeter data, the results showed the unknown residuals are always positive under the circumstances of the sea level rise above 3.2m. Apart from uncertainties in observing, the residual reflected unknown contributions. Among the total case number of sea level rise above 3.2m is 23 times, 22 of which were recorded with oceanic warm eddy happened simultaneously. The unknown residual seems precisely matched with oceanic warm eddies and illustrates a clear future approach for Tuvaluan to care for.

  3. Mesozoic sea level fluctuations documented on Exmouth Plateau off northwestern Australia

    SciTech Connect

    Haq, B.U.; Blome, C.D.; Bralower, T.J.; Brenner, W.; Oda, M.; Siesser, W.; Wonders, A.A.H.

    1989-03-01

    The Exmouth Plateau is uniquely suited to the study of sea level changes because of the existence of an extensive seismic grid and industry well sites, an extended Mesozoic stratigraphic record punctuated with several major unconformities, and the relatively protected position of this high plateau. Thus, documenting sea level fluctuations was one of the major objectives of drilling on the Exmouth Plateau. This documentation depends on their ability to (1) isolate the tectonic overprint from the eustatic signal by retracing the subsidence histories of the drill sites and (2) accurately date the unconformities. Two transects of sites were drilled, one with four sites on the Wombat Plateau and the other with two sites on the central Exmouth Plateau, with one site located relatively proximally and another distally to the source of sediment supply. Preliminary shipboard work indicates that the age of Mesozoic unconformities can be accurately constrained and the subsidence-related tectonic events can be effectively isolated from sea level fluctuations. Sequence stratigraphic analysis of seismic, lithofacies, biofacies, and well-log data document important Upper Triassic sequence boundaries on the Wombat Plateau between the middle and upper Carnian (Norian-Rhaetian boundary) and in the upper most Rhaetian, whose timing and relative magnitude conform well with the eustatic cycle chart. The sequence boundary and systems tracts recognized in the central Exmouth Plateau Barrow Group equivalent strata (Berriasian-Valanginian) also correspond well with the global cycle chart. These preliminary results are of considerable importance in providing a test of the validity of the eustatic model.

  4. Intermittent sea-level acceleration

    NASA Astrophysics Data System (ADS)

    Olivieri, M.; Spada, G.

    2013-10-01

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

  5. Mid-Carboniferous eustatic event

    SciTech Connect

    Saunders, W.B.; Ramsbottom, W.H.C.

    1986-03-01

    Stratigraphic and paleontologic evidence from mid-Carboniferous (Namurian) basin and shelf successions in widely scattered parts of the world indicates that a major eustatic event occurred about 330 Ma. The event began with a regression that is recorded in most shelf sequences, the regression was followed by a brief transgression about 328 Ma, and the event ended with a transgression that flooded large shelf areas about 325 Ma. The Mississippian-Pennsylvanian unconformity in North America is a well-known product of this event, but equally prominent and contemporaneous unconformity surfaces are also present in Europe, North Africa, and elsewhere. The event is believed to have caused numerous extinctions, and it resulted in marked fluctuations in faunal diversity. 94 references, 2 figures.

  6. Ostracode turnover and sea-level changes associated with the Paleocene-Eocene thermal maximum

    NASA Astrophysics Data System (ADS)

    Speijer, Robert P.; Morsi, Abdel-Mohsen M.

    2002-01-01

    The ostracode response to oceanographic changes during the Paleocene-Eocene thermal maximum (PETM, ca. 55 Ma) is largely unknown. The Gebel Duwi section (Egypt) provides a detailed ostracode record across the PETM in a middle neritic setting. Quantitative analysis of this record reveals two significant results. (1) The PETM is marked by a sharp faunal turnover, as indicated by abundance changes, local extinctions, and immigrations. This turnover punctuated a gradual basin-wide faunal transition. (2) During the ˜60 k.y. period prior to the PETM, relative sea level fell rapidly by ˜15 m. This sea-level fall was followed by an ˜20 m sea-level rise during the PETM. A possible eustatic control on these fluctuations suggests the presence of a cryosphere and variations in its size during this time of global warmth.

  7. Late Cretaceous chronology of large, rapid sea-level changes: Glacioeustasy during the greenhouse world

    USGS Publications Warehouse

    Miller, K.G.; Sugarman, P.J.; Browning, J.V.; Kominz, M.A.; Hernandez, J.C.; Olsson, R.K.; Wright, J.D.; Feigenson, M.D.; Van Sickel, W.

    2003-01-01

    We provide a record of global sea-level (eustatic) variations of the Late Cretaceous (99-65 Ma) greenhouse world. Ocean Drilling Program Leg 174AX provided a record of 11-14 Upper Cretaceous sequences in the New Jersey Coastal Plain that were dated by integrating Sr isotopic stratigraphy and biostratigraphy. Backstripping yielded a Late Cretaceous eustatic estimate for these sequences, taking into account sediment loading, compaction, paleowater depth, and basin subsidence. We show that Late Cretaceous sea-level changes were large (>25 m) and rapid (??? m.y.), suggesting a glacioeustatic control. Three large ??18O increases are linked to sequence boundaries (others lack sufficient ??18O data), consistent with a glacioeustatic cause and with the development of small (<106 km3) ephemeral ice sheets in Antarctica. Our sequence boundaries correlate with sea-level falls recorded by Exxon Production Research and sections from northwest Europe and Russia, indicating a global cause, although the Exxon record differs from backstripped estimates in amplitude and shape.

  8. Sea-level curve for Pennsylvanian eustatic marine transgressive-regressive depositional cycles along midcontinent outcrop belt, North America

    NASA Astrophysics Data System (ADS)

    Heckel, Philip H.

    1986-04-01

    At least 55 cycles of marine inundation and withdrawal are recognized in the mid-Desmoinesian to mid-Virgilian Midcontinent outcrop sequence in North America. They range from widespread major cycles (classic cyclothems) with deep-water facies extending across the northern shelf, through intermediate cycles persisting as marine horizons across the shelf, to minor cycles developed on the lower shelf or as parts of major cycles. Biostratigraphic differentiation of the cycles should establish interbasinal correlation on a scale fine enough to allow evaluation of differential tectonics and sedimentation. Sequential groupings of cycles are more irregular than proposed megacyclothems or mesothems, but they may be obscured by the distinctness of the major cyclothems. Estimates of cycle periods range from about 40 to 120 × 103 yr for the minor cycles up to about 235 to 400 × 103 yr for the major cyclothems. The range for all cycles corresponds well to the range of periods of Earth's orbital parameters that constitute the Milankovitch insolation theory for the Pleistocene ice ages, and it further supports Gondwanan glacial control for the Pennsylvanian cycles. Even though the dominant period of the major Pennsylvanian cyclothems is up to four times longer than the dominant 100 000-yr period in the Pleistocene, the shapes of both curves display rapid marine transgression (rapid melting of ice caps) and slow interrupted regression (slow buildup of ice caps), which suggest similar linkages between the climatic effects of the orbital parameters and ice-cap formation and melting, at the two different scales, widely separated in time.

  9. Paleodepth variations on the Eratosthenes Seamount (Eastern Mediterranean): sea-level changes or subsidence?

    NASA Astrophysics Data System (ADS)

    Spezzaferri, S.; Tamburini, F.

    2007-09-01

    The Eratosthenes Seamount (Eastern Mediterranean) is interpreted as a crustal block in process of break up in response to subduction and incipient collision of the African and Eurasian Plates. Subsidence is considered to be the mechanism triggering the Messinian to Pleistocene water deepening above this unique structure. However, the application of a recently developed transfer equation of depth range distribution of benthic foraminifera indicates that sea-level changes may also have played a role, although it was generally minor. In particular, we suggest that across the Miocene/Pliocene boundary and during the Pliocene-Pleistocene, the eustatic signal is frequently coupled with uplifts and subsidence. The uplift of Cyprus across the Pliocene-Pleistocene transition is clearly recorded in the paleodepth curve. Micropaleontological studies and the use of this transfer equation based on the distribution of benthic foraminifera proves to be useful when studying the paleodepth history of complex sites, where tectonic and eustatic signals combine. We also show that marginal seas record global sea-level changes that can be identified even in tectonically active settings.

  10. Post-glacial sea-level change along the Pacific coast of North America

    NASA Astrophysics Data System (ADS)

    Shugar, Dan H.; Walker, Ian J.; Lian, Olav B.; Eamer, Jordan B. R.; Neudorf, Christina; McLaren, Duncan; Fedje, Daryl

    2014-08-01

    Sea-level history since the Last Glacial Maximum on the Pacific margin of North America is complex and heterogeneous owing to regional differences in crustal deformation (neotectonics), changes in global ocean volumes (eustasy) and the depression and rebound of the Earth's crust in response to ice sheets on land (isostasy). At the Last Glacial Maximum, the Cordilleran Ice Sheet depressed the crust over which it formed and created a raised forebulge along peripheral areas offshore. This, combined with different tectonic settings along the coast, resulted in divergent relative sea-level responses during the Holocene. For example, sea level was up to 200 m higher than present in the lower Fraser Valley region of southwest British Columbia, due largely to isostatic depression. At the same time, sea level was 150 m lower than present in Haida Gwaii, on the northern coast of British Columbia, due to the combined effects of the forebulge raising the land and lower eustatic sea level. A forebulge also developed in parts of southeast Alaska resulting in post-glacial sea levels at least 122 m lower than present and possibly as low as 165 m. On the coasts of Washington and Oregon, as well as south-central Alaska, neotectonics and eustasy seem to have played larger roles than isostatic adjustments in controlling relative sea-level changes.

  11. USACE Extreme Sea levels

    DTIC Science & Technology

    2014-03-14

    into Extreme Water Level Characterization 9 September 2013 Attendees: Heidi Moritz, Kate White, Jonathan Simm, Robert Nicholls, Peter Hawkes...adaptation. Robert Nicholls raised the question of how well do we feel that we understand the present extreme climate? We should start with this area...the peer-review and acceptance process for a journal paper. Robert suggested that most of the papers which are needed for an analysis today may be

  12. Constraining mid to late Holocene sea level change of Society Islands, French Polynesia

    NASA Astrophysics Data System (ADS)

    Juma Rashid, Rashid; Eisenhauer, Anton; Liebetrau, Volker; Fietzke, Jan; Dullo, Christian; Camoin, Gilbert; Hallmann, Nadine

    2013-04-01

    In global average rising eustatic sea level of several centimeters per decade is predicted for the near future as a consequence of seawater warming and partial melting of the Greenland ice cap (Milne et al., 2009). Beside CO2 induced ocean warming local sea-level amplitudes may also vary although no extra water has been added to or extracted from the ocean due to post-glacial geoid reorganization, as a consequence of the emergence of the once glaciated areas and the ocean siphoning effect (Milne et al., 2009; Mitrovica and Peltier, 1991; Mitrovica and Milne, 2002). However, previous research on sea level change was focused on sea-level rise that occurred between the "Last Glacial Maximum, LGM" ~18ka before present (BP) and the so called "Holocene Sea Level Maximum, HSLM" ~6ka BP. Information about sea-level change after the HSLM are rare because the Late Holocene was considered to be climatically stable with minor to negligible sea-level oscillations and amplitudes. Here we present U/Th dated fossil corals from conglomerate reef platforms of three islands (Moorea, Huahine and Bora Bora) of the Society Islands, French Polynesia. The fossil coral data constrain the timing and amplitude of sea-level variations after the HSLM. We found that sea level reached a subsidence corrected minimum position of ~1.5±0.2m above present sea level (apsl) at ~5.4ka. Sea level then remained at this position with probably minor amplitudinal variations for ~3ka and then dropped to the present position at ~1.9ka. Note, that our study does not provide any data on sea-level position from ~1.8ka to the Present. Theoretical predictions (Mitrovica and Milne, 2002) taking the ocean siphoning effect into account predicted a sea level of ~3m apsl at ~5ka and a constantly decreasing sea level from 5ka to the present. This is in contrast to our observations indicating a more or less constant sea level between 5ka and 1.9ka followed by a abrupt drop of sea level to the present position. Although

  13. Post-Miocene diagenetic and eustatic history of Enewetak Atoll: Model and data comparison

    NASA Astrophysics Data System (ADS)

    Quinn, Terrence M.; Matthews, R. K.

    1990-10-01

    The post-Miocene diagenetic and eustatic history of Enewetak Atoll was investigated using a one-dimensional forward model. Comparison of model and data suggests that the post-Miocene history of Enewetak Atoll was dominated by multiple episodes of meteoric phreatic diagenesis attendant with high-frequency (104 to 105 yr) fluctuations in sea level and a subsidence rate of 39.0 m/m.y. Sensitivity testing indicates that subaerial erosion results in the preservation of additional subaerial unconformities because stratigraphic shortening permits a succeeding sea-level rise to flood the exposure surface and deposit sediment, whereas without subaerial erosion this sea-level rise would be recorded as a paleophreatic lens. Model results indicate that less than 10% of lapsed time is recorded by sediment deposition during periods of high-frequency changes in sea level. Incompleteness of the stratigraphic record suggests that magnetostratigraphy may give erroneous ages for shallow-marine carbonate sequences deposited during times of high-frequency changes in sea level and frequent magnetic polarity reversals.

  14. Sedimentary architecture of the Bohai Sea China over the last 1 Ma and implications for sea-level changes

    NASA Astrophysics Data System (ADS)

    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.

  15. Seismic sequence stratigraphy of Miocene deposits related to eustatic, tectonic and climatic events, Cap Bon Peninsula, northeastern Tunisia

    NASA Astrophysics Data System (ADS)

    Gharsalli, Ramzi; Zouaghi, Taher; Soussi, Mohamed; Chebbi, Riadh; Khomsi, Sami; Bédir, Mourad

    2013-09-01

    The Cap Bon Peninsula, belonging to northeastern Tunisia, is located in the Maghrebian Alpine foreland and in the North of the Pelagian block. By its paleoposition, during the Cenozoic, in the edge of the southern Tethyan margin, this peninsula constitutes a geological entity that fossilized the eustatic, tectonic and climatic interactions. Surface and subsurface study carried out in the Cap Bon onshore area and surrounding offshore of Hammamet interests the Miocene deposits from the Langhian-to-Messinian interval time. Related to the basin and the platform positions, sequence and seismic stratigraphy studies have been conducted to identify seven third-order seismic sequences in subsurface (SM1-SM7), six depositional sequences on the Zinnia-1 petroleum well (SDM1-SDM6), and five depositional sequences on the El Oudiane section of the Jebel Abderrahmane (SDM1-SDM5). Each sequence shows a succession of high-frequency systems tract and parasequences. These sequences are separated by remarkable sequence boundaries and maximum flooding surfaces (SB and MFS) that have been correlated to the eustatic cycles and supercycles of the Global Sea Level Chart of Haq et al. (1987). The sequences have been also correlated with Sequence Chronostratigraphic Chart of Hardenbol et al. (1998), related to European basins, allows us to arise some major differences in number and in size. The major discontinuities, which limit the sequences resulted from the interplay between tectonic and climatic phenomena. It thus appears very judicious to bring back these chronological surfaces to eustatic and/or local tectonic activity and global eustatic and climatic controls.

  16. Deciphering the mid-Carboniferous eustatic event in the central Appalachian foreland basin, southern West Virginia, USA

    USGS Publications Warehouse

    Blake, B.M.; Beuthin, J.D.

    2008-01-01

    A prominent unconformity, present across shallow shelf areas of the Euramerican paleoequatorial basins, is used to demark the boundary between the Mississippian and Pennsylvanian subsystems. This unconformity, the mid-Carboniferous eustatic event, is generally attributed to a major glacio-eustatic sea-level fall. Although a Mississippian-Pennsylvanian unconformity is recognized throughout most of the Appalachian region, the record of the mid-Carboniferous eustatic event in the structurally deepest part of the basin has been controversial. Based on early reports that suggested the most complete Pennsylvanian section was present in southern West Virginia, various conceptual depositional models postulated continuous sedimentation between the youngest Mississippian Bluestone Formation and the oldest Penn-sylvanian Pocahontas Formation. In contrast, tabular-erosion models envisioned axial drainage systems that evolved in response to changing basin dynamics. These models predicted a Mississippian-Pennsylvanian unconformity. All these models suffered from a lack of biostratigraphic control. The presence of a sub-Pocahontas paleovalley, herein named the Lashmeet paleovalley, has been confirmed in southern West Virginia. The Lashmeet paleovalley was incised over 35 m into Bluestone strata and filled by lithic sands derived from the Appalachian orogen to the northeast and east. The polygenetic Green Valley paleosol complex marks the Bluestone-Pocahontas contact on associated interfluves. Together, these features indicate a substantial period of subaerial exposure and argue strongly in favor of a Mississippian-Pennsylvanian unconformity. Paleontologic data from the Bluestone Formation, including marine invertebrates and conodonts from the marine Bramwell Member and paleofloral data, support a late, but not latest, Arnsbergian age assignment. Marine fossils are not known from the Pocahontas Formation, but macrofloral and palynomorph taxa support a Langsettian age for most of

  17. Holocene Sea-Level Database For The Caribbean Region

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  18. Sea level change since the Pliocene - a new formalism for predicting sea level in the presence of dynamic topography and isostasy

    NASA Astrophysics Data System (ADS)

    Austermann, Jacqueline; Rovere, Alessio; Moucha, Robert; Mitrovica, Jerry X.; Rowley, David B.; Forte, Alessandro M.; Raymo, Maureen E.

    2014-05-01

    Dynamic topography (DT), as reflected in local sea level change, provides a unique lens for studying the imprint of deep Earth dynamics on the Earth's surface. The elevation of paleo-shorelines over long time scales is, however, not only perturbed by DT but also by glacial isostatic adjustment (GIA) and eustatic changes in sea level. Isolating these contributions is essential for efforts to constrain past changes in ice volume or mantle convection models. Previous studies have performed this separation by modeling dynamic topography and superimposing the signal on the elevation of a GIA-corrected paleo-shoreline. However, this approach neglects deformation of the Earth in response to changes in the ocean load and geometry driven by DT. We describe a generalized, gravitationally self-consistent framework for computing sea-level changes that incorporates DT and GIA. The formalism is based on a sea-level theory developed within the GIA community that takes accurate account of viscoelastic deformation of the solid Earth, perturbations in the gravity field, migration of shorelines and the feedback into sea-level of contemporaneous (load-induced) changes in Earth rotation. Specifically, dynamic topography is introduced as a perturbation to the elevation of the solid surface that does not load the Earth because it is dynamically supported. However, water that is displaced by DT is allowed to redistribute, perturb the gravitational field and load (or unload) the ocean floor wherever the water column is increased (or decreased). The problem is complicated by plate tectonics, which (in a tectonic reference frame) leaves changes in topography and DT undefined in areas of the ocean floor where plates have been subducted. We interpolate these regions by imposing mass conservation of both the solid Earth and water on the reconstructed topography. We use the new formalism to calculate sea level change since the mid-Pliocene (3 Ma) using recent global simulations of dynamic

  19. Late mid-Holocene sea-level oscillation: A possible cause

    NASA Astrophysics Data System (ADS)

    Scott, D. B.; Collins, E. S.

    Sea level oscillated between 5500 and 3500 years ago at Murrells Inlet, South Carolina, Chezzetcook and Baie Verte, Nova Scotia and Montmagny, Quebec. The oscillation is well constrained by foraminiferal marsh zonations in three locations and by diatoms in the fourth one. The implications are: (1) there was a eustatic sea-level oscillation of about 2-10 m in the late mid-Holocene on the southeast coast of North America (South Carolina to Quebec) that is not predicted by present geophysical models of relative sea-level change; (2) this oscillation coincides with oceanographic cooling on the east coast of Canada that we associate with melting ice; and (3) this sea- level oscillation/climatic event coincides exactly with the end of pyramid building in Egypt which is suggested to have resulted from a climate change (i.e. drought, cooling). This sea-level/climatic change is a prime example of feedback where climatic warming in the mid-Holocene promoted ice melt in the Arctic which subsequently caused climatic cooling by opening up Arctic channels releasing cold water into the Inner Labrador Current that continued to intensify until 4000 years ago. This sea-level event may also be the best way of measuring when the final ice melted since most estimates of the ages of the last melting are based on end moraine dates in the Arctic which may not coincide with when the last ice actually melted out, since there is no way of dating the final ice positions.

  20. Sea level change and glacio-hydro isostasy deduced from some Italian marine notches

    NASA Astrophysics Data System (ADS)

    Antonioli, F.; Carulli, G. B.; Marocco, R.

    2003-04-01

    Sea level change along the Italian coast is the sum of eustatic, glacio-hydro-isostatic, and tectonic factors (Lambeck et al.,submitted 2003). Marine notches are frequently found in limestones lithologies. A marine notch is normally carved in 2-5 centuries and this range depends upon the lithology. The use of notches as sea level marker in a low-tide seas as Mediterranean, is crucial to study the sea level change. In many Italian tectonically active coastal zone uplifting (eastern Sicily) o subsiding (Trieste, north Adriatic sea) the Present day marine notches are lacking because the tectonic ratea are faster than the possibility of carving. A submerged marine notch was discovered at Trieste at an altitude (tidally corrected) of -1.9 m; a similar notch, at an altitude of -0.6, was measured by Fouache et al., (2000) along Croatian coast, but while at Trieste the Present day marine notch is lacking, along Croatian coast, instead, this notch is well carved. This should result from complex equilibrium between eustatic sea level, hydro-glacio isostasy and tectonic that must be different between Trieste and Croatian coast. The deeper submerged marine notch on limestones of Trieste is suitable with an Plio-quaternary tilting of the Carso plateau, gently dipping to NW, as illustrated by other observations by Carulli et al.,(1980). This fact may be related also to the increasing weight of the external fronts of the South-alpine chain and to the External Dinarides one. Both, characterized by strong seismic activity and consequent neotectonics effects, are rising and advancing not far from Trieste. In a tectonically stable zone as Gaeta (Central Tyrrhenian sea) the submerged cliff immediately belove the present day marine notch was monitored (Antonioli, 1989) and was discovered a smoothed morphology similar to a very large marine notch. Such composite morphology made off from two different notches (in 4-5 meters of submerged cliff) is present also as fossil and related to

  1. Climatic-eustatic control of Holocene nearshore parasequence development, southeastern Texas coast

    USGS Publications Warehouse

    Morton, Robert A.; Kindinger, Jack G.; Flocks, James G.; Stewart, Laura B.

    1999-01-01

    Sediment cores, seismic profiles, radiocarbon dates, and faunal assemblages were used to interpret the depositional setting and geological evolution of the southeastern Texas coast during the last glacio-eustatic cycle. Discrete lithofacies and biofacies zones in the ebb-dominated Sabine Lake estuary and adjacent chenier plain record alternating periods of rapid marine flooding and gradual shoaling related to linked climatic/eustatic fluctuations. Monospecific zones of the mollusks Rangia cuneata and Crassostrea virginica, respectively, indicate high fresh water outflow followed by invasion of marine water, whereas intervening organic-rich zones record bayhead delta deposition. High-frequency parasequence stacking patterns within the valley fill and across the adjacent interfluve reflect an initial rapid rise in sea level about 9 ka that flooded abandoned alluvial terraces and caused onlap of Holocene marsh in the incised valley. The rapid rise was followed by slowly rising and oscillating sea level that filled the deepest portions of the incised valleys with fluvially dominated estuarine deposits, and then a maximum highstand (+1 m msl) about 5 ka that flooded the former subaerial coastal plain between the incised valleys and constructed the highest beach ridges. Between 3.5 and 1.5 ka, sea level oscillated and gradually fell, causing a forced regression and rapid progradation of both the chenier plain and accretionary barrier islands. The only significant sands in the valley fill are (1) falling-stage and lowstand-fluvial sediments between the basal sequence boundary and transgressive surface unconformity, and (2) highstand beach-ridge sediments of the chenier plain.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Eustatic and tectonic control of sedimentation in the Pennsylvanian strata of the Central Appalachian Basin

    SciTech Connect

    Chesnut, D.R. Jr. . Kentucky Geological Survey)

    1992-01-01

    Analysis of the Breathitt Group of the Central Appalachian Basin reveals three orders of depositional cycles or trends. The Breathitt coarsening-upward trend (20 million years (my)) represents increasing intensity of the Alleghenian Orogeny. The major transgression (MT) cycle (2.5 my) was controlled by an unknown eustatic or tectonic mechanism. The major coal beds and intervening strata make up the coal-clastic cycle (CC cycle) (=Appalachian cyclothem) which has a 0.4 my periodicity. This periodicity supports eustatic control of sedimentation modulated by an orbital periodicity. Extensive coastal peats deposited at lowstand (CC cycle) were preserved as coals, whereas highstand peats were eroded during the subsequent drop in sea level. Autocyclic processes such as delta switching and avulsion occurred within CC cycles. An Early Pennsylvanian unconformity represents uplift and erosion of mid-Carboniferous foreland basin deposits. Alluvial deposits (Breathitt Group) derived from the highlands were transported to the northwest toward the forebulge. During lowstand, the only outlet available to further sediment transport (Lee sandstones) was toward the southwest (Ouachita Trough), along the Black Warrior-Appalachian foreland basins. The Middle Pennsylvanian marks a period of intermittent overfilling of the foreland basin and cresting of the forebulge. Marine transgressions entered through the foreland basins and across saddles in the forebulge. After the Ouachita Trough was destroyed during the late Middle Pennsylvanian, marine transgressions migrated only across saddles in the forebulge. In the Late Pennsylvanian, marine waters entered the basin only across the diminished forebulge north of the Jessamine Dome.

  4. Cold climate deglaciation prior to termination 2 implied by new evidence for high sea-levels at 132 KA

    SciTech Connect

    Johnson, R.G. . Dept. of Geology and Geophysics)

    1992-01-01

    Radioisotope dating of corals from reefs and beaches suggests a high sea stand just prior to termination 2. Lack of precision in the ages, stratigraphic uncertainties, and possible diagenetic alterations in the corals have prevented a widespread acceptance of this sea stand. These disadvantages can be avoided by an approach that uses differential uplift measurements to determine the duration of the interval of generally high sea-levels. The last interglacial terrace on Barbados has features indicating two intervals of constant sea-level: an older wave-cut at the inshore edge of the terrace, and a younger cut formed near present eustatic sea-level, below the crest, and just before the earliest Wisconsin glacial buildup. The differential uplift between these two features, measured at five locations having uplift rates between 0.18 and 0.39m/ka, yields a eustatic sea-level differences of 5.4m and a minimal duration of 12.1 [+-] 0.6ka between the two still stands. The assigned age of the younger wave-cut is 120 [+-] 0.5ka, based on sea-level regression due to ice sheet buildup implied by a Little Ice Age analog and rapidly falling Milankovitch summer insolation. The resulting minimal age of the first high sea-stand is 132.1 [+-] 1.1ka, about 7ka before termination 2. This age implies a major early deglaciation caused by a deficit of moisture transported to the great ice sheets, and occurring under relatively cold climate conditions.

  5. A new Holocene sea-level database for the US Gulf Coast: Improving constraints for past and future sea levels

    NASA Astrophysics Data System (ADS)

    Hijma, M.; Tornqvist, T. E.; Hu, P.; Gonzalez, J.; Hill, D. F.; Horton, B. P.; Engelhart, S. E.

    2011-12-01

    The interpretation of present-day sea-level change, as well as the prediction of future relative sea-level (RSL) rise and its spatial variability, depend increasingly on the ability of glacial isostatic adjustment (GIA) models to reveal non-eustatic components of RSL change. GIA results from the redistribution of mass due to the growth and decay of ice sheets. As a consequence, formerly ice-covered areas are still rebounding and currently experience RSL fall, while in other areas the rate of RSL rise is enhanced due to glacial forebulge collapse. The development of GIA models relies to a large extent on the availability of quality-controlled Holocene RSL data. There is thus an urgent need for systematically compiled and publicly available databases of geological RSL data that can be used not only for the purposes mentioned above, but also can serve to underpin coastal management and policy decisions. We have focused our efforts to develop a Holocene sea-level database for the Atlantic and Gulf coasts of the US. Many of the research problems that can be addressed with this sea-level database revolve around the identification of crustal motions due to glacial forebulge collapse that affects the entire region and likely extends beyond South Florida. For the east coast, GIA-related subsidence rates have been calculated with unprecedented precision: <0.8 mm a-1 in Maine, increasing to rates of 1.7 mm a-1 in Delaware, and a return to rates <0.9 mm a-1 in the Carolinas. Here, we first define our methodology to reconstruct RSL, with particular reference to the quantification of age and elevation errors. Many sea-level indicators are related to a specific tide level (e.g., peat that formed between highest astronomical tide and mean high water level). We use paleotidal modeling to account for any changes during the Holocene. We furthermore highlight a number of errors associated with 14C dating that have rarely, if ever, been considered in previous studies of this nature

  6. Clathrate eustasy: Methane hydrate melting as a mechanism for geologically rapid sea-level fall

    USGS Publications Warehouse

    Bratton, J.F.

    1999-01-01

    Although submarine methane hydrates or clathrates have been highlighted as potential amplifiers of modern global climate change and associated glacio-eustatic sea-level rise, their potential role in sea-level fall has not been appreciated Recent estimates of the total volume occupied by gas hydrates in marine sediments vary 20-fold, from 1.2 ?? 1014 to 2.4 ?? 1015 m3. Using a specific volume change on melting of-21%, dissociation of the current global inventory of hydrate would result in a decrease of submarine hydrate volume of 2.4 ?? 1013 to 5.0??1014 m3. Release of free gas bubbles present beneath hydrates would increase these volumes by 1.1-2.0 ?? 1013 m3. The combined effects of hydrate melting and subhydrate gas release would result conservatively in a global sea-level fall of 10-146 cm. Such a mechanism may offset some future sea-level rise associated with thermal expansion of the oceans. It could also explain anomalous sea-level drops during ice-free periods such as the early Eocene, the Cretaceous, and the Devonian.

  7. Late Quaternary variations in relative sea level due to glacial cycle polar wander

    USGS Publications Warehouse

    Bills, B.G.; James, T.S.

    1996-01-01

    Growth and decay of continental ice sheets can excite significant motion of the Earth's rotation pole and cause a complex spatio-temporal pattern of changes in relative sea level. These two effects have generally been considered separately, but may interact in important ways. In particular, a simple model of the melting of the Laurentide ice sheet causes a uniform eustatic sea level rise of 55 m, and also induces a motion of the rotation pole by 0.1 to 1 degree, depending on viscosity structure in the mantle. This motion produces a secular pole tide, which is a spherical harmonic degree 2, order 1 component of the relative sea level pattern, with peak-to-peak amplitude of 20 to 40 m. The maximum effect is along the great circle passing through the path of the pole and at latitudes of ??45??. This secular pole tide has been ignored in most previous attempts to estimate ice sheet loading history and mantle viscosity from global patterns of relative sea level change. It has a large influence along the East coast of North America and the West coast of South America, and significantly contributes to present day rates of relative sea level change.

  8. Holocene relative sea level rise and subsidence in northern Gulf of Mexico

    SciTech Connect

    Penland, S.; Sutter, J.R.; Ramsey, K.E.; McBride, R.D.

    1988-01-01

    The analysis of more than 90 tidal gauge records, 10,000-km high resolution seismic profiles, 500 vibracores, and 250 radiocarbon dates led to the development of a new sea level history for the Louisiana coastal zone and adjacent continental shelf for the last 8,000 years. Now reinterpreted, the original single delta plain is seen as actually two individual, imbricated shelf-phase delta plains deposited at different sea levels. Termed the modern and late Holocene, these two delta plains are separated by a regional shoreface refinement surface, which can be traced updip to the relict-transgressive Teche shoreline. The Late Holocene delta plain was deposited during a sea level stillstand 6 m below the present, 3,000-7,2000 years ago. A 5 to 6-m eustatic-enhanced relative rise in sea level, 2,5000-3,000 years ago at a rate of 1-1.2 cm/yr led to the complete transgresive submergence of the lower late Holocene delta plain. Sea level reached its approximate position about 2,500 years ago, and since then the Mississippi River has built the modern delta plain consisting of the abandoned St. Bernard and Lafourche delta complexes and the active Balize and Atchafalaya delta complexes.

  9. Clathrate eustasy: Methane hydrate melting as a mechanism for geologically rapid sea-level fall

    SciTech Connect

    Bratton, J.F.

    1999-10-01

    Although submarine methane hydrates or clathrates have been highlighted as potential amplifiers of modern global climate change and associated glacio-eustatic sea-level rise, their potential role in sea-level fall has not been appreciated. Recent estimates of the total volume occupied by gas hydrates in marine sediments vary 20-fold, from 1.2 x 10{sup 14} to 2.4 x 10{sup 15} m{sup 3}. Using a specific volume change on melting of {minus}21%, dissociation of the current global inventory of hydrate would result in a decrease of submarine hydrate volume of 2.4 x 10{sup 13} to 5.0 x 10{sup 14} m{sup 3}. Release of free gas bubbles present beneath hydrates would increase these volumes by 1.1 --2.0 x 10{sup 13} m{sup 3}. The combined effects of hydrate melting and subhydrate gas release would result conservatively in a global sea-level fall of 10--146 cm. Such a mechanism may offset some future sea-level rise associated with thermal expansion of the oceans. It could also explain anomalous sea-level drops during ice-free periods such as the early Eocene, the Cretaceous, and the Devonian.

  10. Sea-Level Projections from the SeaRISE Initiative

    NASA Technical Reports Server (NTRS)

    Nowicki, Sophie; Bindschadler, Robert

    2011-01-01

    SeaRISE (Sea-level Response to Ice Sheet Evolution) is a community organized modeling effort, whose goal is to inform the fifth IPCC of the potential sea-level contribution from the Greenland and Antarctic ice sheets in the 21st and 22nd century. SeaRISE seeks to determine the most likely ice sheet response to imposed climatic forcing by initializing an ensemble of models with common datasets and applying the same forcing to each model. Sensitivity experiments were designed to quantify the sea-level rise associated with a change in: 1) surface mass balance, 2) basal lubrication, and 3) ocean induced basal melt. The range of responses, resulting from the multi-model approach, is interpreted as a proxy of uncertainty in our sea-level projections. http://websrv.cs .umt.edu/isis/index.php/SeaRISE_Assessment.

  11. North Sea coast levelling net: A model case for the determination of vertical movements in Western Europe

    NASA Astrophysics Data System (ADS)

    Augath, W.; Pelzer, H.

    In Northern Germany, permanent tide gauge records have been available for investigations since about 1850. As a result of such investigations it was found that in the North Sea the mean sea level (MSL) seems to increase by an amount of approximately 2 mm/year being nearly twice the amount of the eustatic change of the MSL recorded all over the world. This result suggested a coastal subsidence of about 1 mm/year. In order to study this effect in more detail a special precise leveling net (North Sea Coast Leveling Net, NKN) was established after 1910 and observed repeatedly. A tendency toward land subsidence was discovered, the amounts determined lying within their statistical confidence regions. The Hanover analysis was established for the computation of vertical crustal movements. The computation and results are detailed.

  12. Tectonic vs. eustatic controls on Ordovician deposition in the Alabama Appalachians

    SciTech Connect

    Benson, D.J. . Dept. of Geology)

    1992-01-01

    The Lower Ordovician section consists of a thick (> 1,500 ft.) sequence of peritidal to shallow subtidal carbonates deposited on a broad, stable platform. Initial Taconic orogenic activity during Late Canadian time downwarped the southeastern margin of the continent and resulted in deposition of a unique subtidal unit. A fall in eustatic sea level during Early Whiterockian time exposed the majority of the platform and produced the Post-Knox unconformity, a major regional unconformity that truncates Upper Cambrian-Lower Ordovician carbonates across the Alabama Appalachians. Middle Ordovician deposition began as a result of eustatic sea level rise and continued downwarping of the SE margin of the North American continent. Initial Middle Ordovician deposits are peritidal carbonates that onlap the Post-Knox unconformity from SE to NW. Continued loading of the margin of the continent led to formation of a deep-water basin to the SE and the concurrent development of a peripheral bulge in the vicinity of what is now the Birmingham anticlinorium. Peritidal carbonates to the SE pass upward into shallow ramp carbonates, deep-ramp mixed carbonate/clastic deposits, and, finally, basinal organic shales. As the deep-water basin evolved, shallow ramp carbonates onlapped the peripheral bulge to the NW. The rapidly evolving basin trapped terrigeneous deposits shed from tectonic highlands to the E and SE permitting deposition of shallow to deep ramp, skeletal carbonates to the NW. Continued tectonic loading led to migration and the ultimate inundation of the peripheral bulge. By Late Mohawkian time, filling of the basin allowed terrigeneous sediments derived from the tectonic highlands to prograde westward, onlap and carbonate ramp, and, finally, terminate carbonate deposition.

  13. CO2 and sea level

    NASA Astrophysics Data System (ADS)

    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.

  14. Freeboard, sea level and dynamic topography during aggregation of a supercontinent

    NASA Astrophysics Data System (ADS)

    Guillaume, B.; Husson, L.; Choblet, G.

    2012-04-01

    The long-term evolution of sea level is a combination of eustatic mechanisms (tectono-eustatism, distribution of continental masses through orogenesis and sedimentation) and non-uniform processes (dynamic topography, geoid, wander of the Earth rotation pole). Given the potentially similar amplitude of both factors, there is a bias in the observation of absolute sea level. Moreover, over large time-scales, and more specifically over the Wilson cycle time-scale, plate aggregation and separation are associated both with (i) variations of the flow pattern and (ii) thermal state in the mantle, which in turn may induce specific vertical motions of the surface. By changing the size of the oceanic and continental water reservoirs, large-scale dynamic topography associated with subduction or the presence of mantle plumes controls rises or drops of sea level, which in turn controls part of the stratigraphic record. The Earth has known periods of continental aggregation and fragmentation that redistribute the location of plate boundaries, especially the location and the length of subduction zones, that could potentially affect sea level. The distribution of mass anomalies in the mantle with respect to continents may therefore have a significant impact. To test the possible correlation between sea level changes and the Wilson cycle, we decide to first focus on the Pangea, which is known to be a period during which most subductions took place beneath continents. We run a set of Earth-like instantaneous flow model using the OEDIPUS (Origin, Evolution and Dynamics of the Interiors of Planets Using Simulation) tool, which allows spherical geometries with lateral viscosity variations. In these models, Pangea is modeled by a spherical continental cap, covering 29% of the planet surface, and floating above a two-layered viscous mantle. We vary parameters such as the dip of the subducting panel, the depth reached by the slab, the viscosity structure and the plate thickness within

  15. Diagenesis and porosity development associated with major sea level fluctuations, Upper Permian, Jameson land, east Greenland

    SciTech Connect

    Scholle, P.A.; Ulmer, D.S. ); Stemmerik, L. )

    1990-05-01

    The Upper Permian of Jameson Land includes two major carbonate sequences, represented by the Karstryggen and Wegener Halvoe formations. The initial Karstryggen transgression led to the development of a shallow marine platform with structurally controlled evaporite basins (salinas) separated by stromatolitic, peloidal, or micritic carbonate depositional areas. The Wegener Havloe sequence reflects more rapid and extensive transgression with the deposition of three subcycles of fully marine, platform, or biohermal carbonates containing minor evaporites near the basin margins. Bioherms (bryozoan-brachiopod-marine cement mounds) show > 100 m of relief, indicating that large relative sea level changes were involved. Both the Karstryggen and Wgener Havloe cycles were terminated by major regressions, which led to karstic and/or fluvial incision of the underlying sequences. Not surprisingly, carbonate and evaporite diagenesis was greatly affected by these regional or eustatic sea level fluctuations. Evaporites dissolved or were replaced by calcite and celestite under the influence of meteoric waters. Limestones show collapse brecciation, grain leaching, soil development, and characteristic vadose and phreatic cements. Most significantly meteoric flushing led to massive dissolution of botryoidal marine cements (aragonite and probable high-Mg calcite) within biohermal facies on the Wegener Peninsula. This early porosity resurrection led to the preservation of porous bioherm core zones until hydrocarbon migration. Only late (posthydrocarbon), probably hydrothermal fluid flow led to cementation of the bioherm cores while expelling most of the reservoired hydrocarbons. If the sea level changes affecting the Greenlandic Permian are eustatic, then this study may provide significant clues to porosity development throughout the largely unexplored northern Zechstein basin.

  16. Late Pleistocene Sea level on the New Jersey Margin: Implications to eustasy and deep-sea temperature

    USGS Publications Warehouse

    Wright, J.D.; Sheridan, R.E.; Miller, K.G.; Uptegrove, J.; Cramer, B.S.; Browning, J.V.

    2009-01-01

    We assembled and dated a late Pleistocene sea-level record based on sequence stratigraphy from the New Jersey margin and compared it with published records from fossil uplifted coral reefs in New Guinea, Barbados, and Araki Island, as well as a composite sea-level estimate from scaling of Red Sea isotopic values. Radiocarbon dates, amino acid racemization data, and superposition constrain the ages of large (20-80??m) sea-level falls from New Jersey that correlate with Marine Isotope Chrons (MIC) 2, 3b, 4, 5b, and 6 (the past 130??kyr). The sea-level records for MIC 1, 2, 4, 5e, and 6 are similar to those reported from New Guinea, Barbados, Araki, and the Red Sea; some differences exist among records for MIC 3. Our record consistently provides the shallowest sea level estimates for MIC3 (??? 25-60??m below present); it agrees most closely with the New Guinea record of Chappell (2002; ??? 35-70??m), but contrasts with deeper estimates provided by Araki (??? 85-95??m) and the Red Sea (50-90??m). Comparison of eustatic estimates with benthic foraminiferal ??18O records shows that the deep sea cooled ??? 2.5????C between MIC 5e and 5d (??? 120-110??ka) and that near freezing conditions persisted until Termination 1a (14-15??ka). Sea-level variations between MIC 5b and 2 (ca. 90-20??ka) follow a well-accepted 0.1???/10??m linear variation predicted by ice-growth effects on foraminiferal ??18O values. The pattern of deep-sea cooling follows a previously established hysteresis loop between two stable modes of operation. Cold, near freezing deep-water conditions characterize most of the past 130??kyr punctuated only by two warm intervals (the Holocene/MIC 1 and MIC 5e). We link these variations to changes in Northern Component Water (NCW). ?? 2009 Elsevier B.V. All rights reserved.

  17. Global change and relative sea level rise at Venice: what impact in term of flooding

    NASA Astrophysics Data System (ADS)

    Carbognin, Laura; Teatini, Pietro; Tomasin, Alberto; Tosi, Luigi

    2010-11-01

    Relative sea level rise (RSLR) due to climate change and geodynamics represents the main threat for the survival of Venice, emerging today only 90 cm above the Northern Adriatic mean sea level (msl). The 25 cm RSLR occurred over the 20th century, consisting of about 12 cm of land subsidence and 13 cm of sea level rise, has increased the flood frequency by more than seven times with severe damages to the urban heritage. Reasonable forecasts of the RSLR expected to the century end must be investigated to assess the suitability of the Mo.S.E. project planned for the city safeguarding, i.e., the closure of the lagoon inlets by mobile barriers. Here we consider three RSLR scenarios as resulting from the past sea level rise recorded in the Northern Adriatic Sea, the IPCC mid-range A1B scenario, and the expected land subsidence. Available sea level measurements show that more than 5 decades are required to compute a meaningful eustatic trend, due to pseudo-cyclic 7-8 year long fluctuations. The period from 1890 to 2007 is characterized by an average rate of 0.12 ± 0.01 cm/year. We demonstrate that linear regression is the most suitable model to represent the eustatic process over these 117 year. Concerning subsidence, at present Venice is sinking due to natural causes at 0.05 cm/year. The RSLR is expected to range between 17 and 53 cm by 2100, and its repercussions in terms of flooding frequency are associated here to each scenario. In particular, the frequency of tides higher than 110 cm, i.e., the value above which the gates would close the lagoon to the sea, will increase from the nowadays 4 times per year to a range between 20 and 250. These projections provide a large spread of possible conditions concerning the survival of Venice, from a moderate nuisance to an intolerable aggression. Hence, complementary solutions to Mo.S.E. may well be investigated.

  18. Late Cretaceous to Miocene sea-level estimates from the New Jersey and Delaware coastal plain coreholes: An error analysis

    USGS Publications Warehouse

    Kominz, M.A.; Browning, J.V.; Miller, K.G.; Sugarman, P.J.; Mizintseva, S.; Scotese, C.R.

    2008-01-01

    Sea level has been estimated for the last 108 million years through backstripping of corehole data from the New Jersey and Delaware Coastal Plains. Inherent errors due to this method of calculating sea level are discussed, including uncertainties in ages, depth of deposition and the model used for tectonic subsidence. Problems arising from the two-dimensional aspects of subsidence and response to sediment loads are also addressed. The rates and magnitudes of sea-level change are consistent with at least ephemeral ice sheets throughout the studied interval. Million-year sea-level cycles are, for the most part, consistent within the study area suggesting that they may be eustatic in origin. This conclusion is corroborated by correlation between sequence boundaries and unconformities in New Zealand. The resulting long-term curve suggests that sea level ranged from about 75-110 m in the Late Cretaceous, reached a maximum of about 150 m in the Early Eocene and fell to zero in the Miocene. The Late Cretaceous long-term (107 years) magnitude is about 100-150 m less than sea level predicted from ocean volume. This discrepancy can be reconciled by assuming that dynamic topography in New Jersey was driven by North America overriding the subducted Farallon plate. However, geodynamic models of this effect do not resolve the problem in that they require Eocene sea level to be significantly higher in the New Jersey region than the global average. ?? 2008 The Authors. Journal compilation ?? 2008 Blackwell Publishing.

  19. Climate-induced variations in lake levels: A mechanism for short-term sea level change during non-glacial times

    SciTech Connect

    Jacobs, D. ); Sahagian, D. . Dept of Geological Sciences)

    1992-01-01

    Variations in insolation due to periodic orbital parameters can cause climatic changes and associated variations in the intensity of monsoonal circulation. This can lead to significant variations in the levels of internally draining lakes on timescales of 10,000 to 100,000 years in regions affected by the monsoon (20,000 years for orbital precession). These variations may be responsible for small scale (few meters) eustatic sea level changes in an ice-free Earth, and may contribute to sea level changes in the presence of ice as well. The authors have estimated the volume of empty present lake basins in the regions of Asia and North Africa influenced by the monsoon. The surface water volume alone of these basins is equivalent to a two meter difference in sea level, but is considerably augmented by groundwater associated with an increase in lake level. The lake variation mechanism for sea level change has its basis in the Quaternary record of climate change and associated explanatory models. However, the argument also applies to earlier, non-glacial periods of geologic time. Clear evidence for the presence of ice in the Triassic is lacking. However, there is evidence for short-term periodic fluctuations of lake levels as well as sea level during that time. These sea level changes, as well as those in the Devonian, Jurassic, and Cretaceous, may be driven by periodic fluctuation in lacustrine and groundwater storage resulting from orbitally forced changes in monsoon intensity, even in the absence of significant glacial ice.

  20. Sea-level control of limestone composition: New data from quaternary carbonates in the Bahamas

    SciTech Connect

    Kindler, P. . Geology Dept.); Hearty, P.J. )

    1993-03-01

    Comprehensive petrographic analysis of limestone in the Bahamas reveals that their composition was ultimately controlled by climatic and sea-level changes during the Quaternary. These results demonstrate that facies analysis of limestone is not only useful for local and regional correlations, but also represents a powerful tool for unraveling the sea-level history of carbonate platforms. Ongoing stratigraphic research across the Bahamas leads to the recognition of nine platform-wide depositional units showing distinctive geomorphic, sedimentologic, petrologic and geochemical features. These units were deposited during major transgressive episodes from the middle Pleistocene to the late Holocene. They are bounded by glacial-age reddish paleosols. Petrographic variations between units do not occur randomly and are not uniquely determined by morphological controls (e.g. bank margin orientation). They are more likely related to climatic and eustatic changes. Oolitic/peloidal units were deposited during warm intervals when the Bahamian platform was totally submerged. Formation of skeletal units reflects cooler periods and partial flooding of the platform when carbonate production was limited to bank-fringing reefs. In conclusion, the limestone units exposed in the Bahamas are sensitive indicators of past sea-level fluctuations. Their composition is controlled by the degree of platform flooding and the rate of sea-level rise, while microfacies analysis has proven useful for paleoclimatic reconstruction.

  1. Regionally differentiated contribution of mountain glaciers and ice caps to future sea-level rise

    NASA Astrophysics Data System (ADS)

    Radić, Valentina; Hock, Regine

    2011-02-01

    The contribution to sea-level rise from mountain glaciers and ice caps has grown over the past decades. They are expected to remain an important component of eustatic sea-level rise for at least another century, despite indications of accelerated wastage of the ice sheets. However, it is difficult to project the future contribution of these small-scale glaciers to sea-level rise on a global scale. Here, we project their volume changes due to melt in response to transient, spatially differentiated twenty-first century projections of temperature and precipitation from ten global climate models. We conduct the simulations directly on the more than 120,000 glaciers now available in the World Glacier Inventory, and upscale the changes to 19 regions that contain all mountain glaciers and ice caps in the world (excluding the Greenland and Antarctic ice sheets). According to our multi-model mean, sea-level rise from glacier wastage by 2100 will amount to 0.124+/-0.037m, with the largest contribution from glaciers in Arctic Canada, Alaska and Antarctica. Total glacier volume will be reduced by 21+/-6%, but some regions are projected to lose up to 75% of their present ice volume. Ice losses on such a scale may have substantial impacts on regional hydrology and water availability.

  2. Responses of a deltaic system to minor relative sea level variations (Middle Jurassic, Cleveland basin, England): Consequences on the reservoir geometry

    SciTech Connect

    Eschard, R.; Ravenne, C. )

    1990-05-01

    In the Middle Jurassic series of the Cleveland basin (England), an accurate three-dimensional reconstruction of depositional sequences from outcrops, cores, and wireline logs show that minor sea level variations control the evolution of a deltaic system. Because of low subsidence and sediment supply rates, rapid sea level rises induce several landward shifts of the shoreline, whereas minor sea level drops produce the incision of small paleovalleys. The deltaic series, 200 m thick at the basin depocenter, are subdivided into five depositional sequences. During the first two sequences, the sediment supply rate exceeds the relative sea level rate and the delta progrades. The delta aggrades during the third depositional sequence and retrogrades in the fourth depositional sequence when the relative sea level rise rate balances then exceeds the sediment supply rate. Finally, a relative sea level drop induces the incision of a paleovalley progressively infilled during the following sea level rise. Several orders of bathymetric cycles are deduced from detailed correlations of the unconformities and from the comparison of the vertical facies succession between low and high subsiding areas. The general evolution of the delta is related to a 5-m.y. bathymetric cycle due to a eustatic sea level rise and fall. Pne to 3-m.y. bathymetric cycles control the main aggradation patterns of the delta. These patterns are related to third-order eustatic cycles or to local tectonic events. Less than 0.5 m.y. bathymetric cycles are registrated by parasequences or minor depositional sequences which are correlated all over the basin. The controlling parameters of the sequences are discussed. Minor bathymetric cycles (0.2 m.y.) reflect small-scale sea level oscillations or autocyclic evolution of the sedimentary bodies. The authors focus on the reservoir geometry within each bathymetric cycle.

  3. Analysis of sea level and sea surface temperature changes in the Black Sea

    NASA Astrophysics Data System (ADS)

    Betul Avsar, Nevin; Jin, Shuanggen; Kutoglu, Hakan; Erol, Bihter

    2016-07-01

    The Black Sea is a nearly closed sea with limited interaction with the Mediterranean Sea through the Turkish Straits. Measurement of sea level change will provide constraints on the water mass balance and thermal expansion of seawaters in response to climate change. In this paper, sea level changes in the Black Sea are investigated between January 1993 and December 2014 using multi-mission satellite altimetry data and sea surface temperature (SST) data. Here, the daily Maps of Sea Level Anomaly (MSLA) gridded with a 1/8°x1/8° spatial resolution from AVISO and the NOAA 1/4° daily Optimum Interpolation Sea Surface Temperature (OISST) Anomaly data set are used. The annual cycles of sea level and sea surface temperature changes reach the maximum values in November and January, respectively. The trend is 3.16±0.77 mm/yr for sea level change and -0.06±0.01°C/yr for sea surface temperature during the same 22-year period. The observed sea level rise is highly correlated with sea surface warming for the same time periods. In addition, the geographical distribution of the rates of the Black Sea level and SST changes between January 1993 and December 2014 are further analyzed, showing a good agreement in the eastern Black Sea. The rates of sea level rise and sea surface warming are larger in the eastern part than in the western part except in the northwestern Black Sea. Finally, the temporal correlation between sea level and SST time series are presented based on the Empirical Orthogonal Function (EOF) analysis.

  4. Sea level regulated tetrapod diversity dynamics through the Jurassic/Cretaceous interval

    PubMed Central

    Tennant, Jonathan P.; Mannion, Philip D.; Upchurch, Paul

    2016-01-01

    Reconstructing deep time trends in biodiversity remains a central goal for palaeobiologists, but our understanding of the magnitude and tempo of extinctions and radiations is confounded by uneven sampling of the fossil record. In particular, the Jurassic/Cretaceous (J/K) boundary, 145 million years ago, remains poorly understood, despite an apparent minor extinction and the radiation of numerous important clades. Here we apply a rigorous subsampling approach to a comprehensive tetrapod fossil occurrence data set to assess the group's macroevolutionary dynamics through the J/K transition. Although much of the signal is exclusively European, almost every higher tetrapod group was affected by a substantial decline across the boundary, culminating in the extinction of several important clades and the ecological release and radiation of numerous modern tetrapod groups. Variation in eustatic sea level was the primary driver of these patterns, controlling biodiversity through availability of shallow marine environments and via allopatric speciation on land. PMID:27587285

  5. Sea level regulated tetrapod diversity dynamics through the Jurassic/Cretaceous interval

    NASA Astrophysics Data System (ADS)

    Tennant, Jonathan P.; Mannion, Philip D.; Upchurch, Paul

    2016-09-01

    Reconstructing deep time trends in biodiversity remains a central goal for palaeobiologists, but our understanding of the magnitude and tempo of extinctions and radiations is confounded by uneven sampling of the fossil record. In particular, the Jurassic/Cretaceous (J/K) boundary, 145 million years ago, remains poorly understood, despite an apparent minor extinction and the radiation of numerous important clades. Here we apply a rigorous subsampling approach to a comprehensive tetrapod fossil occurrence data set to assess the group's macroevolutionary dynamics through the J/K transition. Although much of the signal is exclusively European, almost every higher tetrapod group was affected by a substantial decline across the boundary, culminating in the extinction of several important clades and the ecological release and radiation of numerous modern tetrapod groups. Variation in eustatic sea level was the primary driver of these patterns, controlling biodiversity through availability of shallow marine environments and via allopatric speciation on land.

  6. Rapid rise in effective sea-level in southwest Bangladesh: Its causes and contemporary rates

    NASA Astrophysics Data System (ADS)

    Pethick, John; Orford, Julian D.

    2013-12-01

    Evidence is presented from three estuarine tide gauges located in the Sundarban area of southwest Bangladesh of relative sea level rise substantially in excess of the generally accepted rates from altimetry, as well as previous tide-gauge analyses. It is proposed that the difference arises from the use of Relative Mean Sea Level (RMSL) to characterise the present and future coastal flood hazard, since RMSL can be misleading in estuaries in which tidal range is changing. Three tide gauges, one located in the uninhabited mangrove forested area (Sundarban) of southwest Bangladesh, the others in the densely populated polder zone north of the present Sundarban, show rates of increase in RMSL ranging from 2.8 mm a- 1 to 8.8 mm a- 1. However, these trends in RMSL disguise the fact that high water levels in the polder zone have been increasing at an average rate of 15.9 mm a- 1 and a maximum of 17.2 mm a- 1. In an area experiencing tidal range amplification, RMSL will always underestimate the rise in high water levels; consequently, as an alternative to RMSL, the use of trends in high water maxima or ‘Effective Sea Level Rise’ (ESLR) is adopted as a more strategic parameter to characterise the flooding hazard potential. The rate of increase in ESLR is shown to be due to a combination of deltaic subsidence, including sediment compaction, and eustatic sea level rise, but principally as a result of increased tidal range in estuary channels recently constricted by embankments. These increases in ESLR have been partially offset by decreases in fresh water discharge in those estuaries connected to the Ganges. The recognition of increases of the effective sea level in the Bangladesh Sundarban, which are substantially greater than increases in mean sea level, is of the utmost importance to flood management in this low-lying and densely populated area.

  7. Delta growth and river valleys: the influence of climate and sea level changes on the South Adriatic shelf (Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Maselli, V.; Trincardi, F.; Asioli, A.; Ceregato, A.; Rizzetto, F.; Taviani, M.

    2014-09-01

    Incised valleys across continental margins represent the response of fluvial systems to changes in their equilibrium dynamics, mainly driven by base level fall forced by glacial-eustatic cycles. The Manfredonia Incised Valley formed during the last glacial sea level lowstand, when most of the southern Adriatic shelf was sub-aerially exposed but the outer shelf remained under water. The pronounced upstream deepening of the valley is ascribed to river incision of the MIS5e highstand coastal prism and related subaqueous clinoform under the influence of MIS5-4 sea level fluctuations, while the downstream shallowing and narrowing mainly reflects the impact of increased rates of sea level fall at the MIS3-2 transition on a flatter mid-outer shelf. Until 15 ka BP, the valley fed an asymmetric delta confined to the mid-outer shelf, testifying that continental and deep marine systems remained disconnected during the lowstand. Sea level rise reached the inner shelf during the Early Holocene, drowning the valley and leading to the formation of a sheltered embayment confined toward the land: at this time part of the incision remained underfilled with a marked bathymetric expression. This mini-basin was rapidly filled by sandy bayhead deltas, prograding from both the northern and southern sides of the valley. In this environment, protected by marine reworking and where sediment dispersal was less effective, the accommodation space was reduced and autogenic processes forced the formation of multiple and coalescing delta lobes. Bayhead delta progradations occurred in few centuries, between 8 and 7.2 ka cal BP, confirming the recent hypothesis that in this area the valley was filled during the formation of sapropel S1. This proximal valley fill, representing the very shallow-water equivalent of the cm-thick sapropel layers accumulated offshore in the deeper southern Adriatic basin, is of key importance in following the signature of the sapropel in a facies-tract ideally from the

  8. Long Term Sea Level Change in the Black Sea

    NASA Astrophysics Data System (ADS)

    Cokacar, Tulay; Emin, Özsoy

    2016-04-01

    Since 1992, altimeter missions have dramatically improved our knowledge and understanding of the oceans.This study investigates the long term sea level change during 1992-2015 in the Black Sea. The satellite altimeter data of the Topex-Poseidon, ERS-1 ands ERS-2 missions and sea level variations of 25 tide gauge stations and temperature/salinity data of 25 Argo float observed in the Black Sea are used for the analysis. The altimeter data are assessed and compared with the data from tide gauges and Argo floats in the Black Sea. First ARGO T/S profiles are used to assess the discrepancies observed between the altimeters. Then in situ measurements are compared with multiple altimeter data to detect in situ measurement anomalies and the corrections applied to improve the consistency of the data sets.

  9. Causes for contemporary regional sea level changes.

    PubMed

    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.

  10. Stratigraphic signature of sub-orbital climate and sea-level changes in the Gulf of Lions (NW Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Berne, S. P.; Bassetti, M. A.; Baumann, J.; Dennielou, B.; Jouet, G.; Mauffrey, M.; Sierro, F. J.

    2014-12-01

    The Promess boreholes in the Gulf of Lions (NW Mediterranean) provide precise chrono-stratigraphic constraints of the last ca 500 ky, that were nicely preserved at the shelf edge due to high accommodation and important sediment supply from the Rhone River. The major stratigraphic elements in this physiographic domain are Falling Stage Systems Tracts (in the sense of SEPM) linked to 100-ky eustatic cycles. They form wedges pinching out on the middle shelf, and thickening seaward on the outer shelf/upper slope (about 30-40m thick on the outer shelf). Within the uppermost sequence, linked to the last Glacial-Interglacial cycle, internal discontinuities were long described, but they were assigned to autogenic processes such as lobe avulsion or bedform migration. However, careful interpretation of a dense grid of very high resolution seismic data, together with precise chronostratigraphic constraints from borehole data and long piston cores, reveal that distinct parasequences, correlable at the regional scale, correspond to relatively minor sea-level changes linked (a) to Bond Cycles during the end of the Last Glacial, and (b) to an early Melt Water Pulse at the onset of Deglacial sea-level rise. These regressive and transgressive (respectively) parasequences are particularly well preserved in canyon heads, due to better accommodation. We propose that such features are important building blocks of the stratigraphic record, that might be recognized elsewhere on modern continental margins, as well as in the rock record.

  11. Quaternary Sea-Level History from the US Atlantic Coastal Plain

    NASA Astrophysics Data System (ADS)

    Poirier, R. K.; Cronin, T. M.; Katz, M. E.; Browning, J. V.; Miller, K. G.; Willard, D. A.

    2014-12-01

    Analyses of emerged Quaternary paleo-shorelines and marine deposits aid in the reconstruction of environmental conditions and variability surrounding recent ice volume and sea-level histories derived from oxygen isotope records. We present preliminary results from a project designed to analyze the age, elevation, and paleoclimate history of Quaternary sediments deposited during sea level highstands along the United States Atlantic Coastal Plain (ACP) from Maryland to Florida. Prior studies have shown that, depending on the region, ACP sediments correlate with past interglacial periods corresponding to Marine Isotope Stages (MIS) 5, 7, possibly 9, and 11. Stratigraphy, marine micropaleontology, and palynology indicate at least two major marine transgressive sequences on the Delmarva Peninsula in Virginia corresponding to MIS 5a and 11, the Nassawadox Formation and Accomack beds of the Omar Formation, respectively. These depositional sequences represent sea-level positions of approximately +10m and +15m, relative to today. Despite generally corresponding to glacio-eustatic sea levels of +5-9m for MIS 5a-e (Potter & Lambeck, 2003; Kopp et al., 2009), and of +6-13m for MIS 11 (Raymo & Mitrovica, 2012), the relative sea-level positions during both interglacial periods were likely affected by glacio-isostatic adjustment in the region. Corresponding marine units and paleo-shorelines, identified by pronounced inland scarps separated by intermittent terraces on the western side of the Chesapeake Bay, are likely from MIS 5, 7, and 11. Ostracode and foraminifera assemblages identify significant environmental variability within these transgressive interglacial deposits, likely driven by relatively minor, suborbital climatic and sea-level oscillations.

  12. Caribbean mangroves adjust to rising sea level through biotic controls on change in soil elevation

    USGS Publications Warehouse

    McKee, K.L.; Cahoon, D.R.; Feller, Ilka C.

    2007-01-01

    Aim The long-term stability of coastal ecosystems such as mangroves and salt marshes depends upon the maintenance of soil elevations within the intertidal habitat as sea level changes. We examined the rates and processes of peat formation by mangroves of the Caribbean Region to better understand biological controls on habitat stability. Location Mangrove-dominated islands on the Caribbean coasts of Belize, Honduras and Panama were selected as study sites. Methods Biological processes controlling mangrove peat formation were manipulated (in Belize) by the addition of nutrients (nitrogen or phosphorus) to Rhizophora mangle (red mangrove), and the effects on the dynamics of soil elevation were determined over a 3-year period using rod surface elevation tables (RSET) and marker horizons. Peat composition and geological accretion rates were determined at all sites using radiocarbon-dated cores. Results The addition of nutrients to mangroves caused significant changes in rates of mangrove root accumulation, which influenced both the rate and direction of change in elevation. Areas with low root input lost elevation and those with high rates gained elevation. These findings were consistent with peat analyses at multiple Caribbean sites showing that deposits (up to 10 m in depth) were composed primarily of mangrove root matter. Comparison of radiocarbon-dated cores at the study sites with a sea-level curve for the western Atlantic indicated a tight coupling between peat building in Caribbean mangroves and sea-level rise over the Holocene. Main conclusions Mangroves common to the Caribbean region have adjusted to changing sea level mainly through subsurface accumulation of refractory mangrove roots. Without root and other organic inputs, submergence of these tidal forests is inevitable due to peat decomposition, physical compaction and eustatic sea-level rise. These findings have relevance for predicting the effects of sea-level rise and biophysical processes on tropical

  13. Patch-reef morphology as a proxy for Holocene sea-level variability, Northern Florida Keys, USA

    USGS Publications Warehouse

    Brock, J.C.; Palaseanu-Lovejoy, M.; Wright, C.W.; Nayegandhi, A.

    2008-01-01

    A portion of the northern Florida Keys reef tract was mapped with the NASA Experimental Advanced Airborne Research Lidar (EAARL) and the morphology of patch reefs was related to variations in Holocene sea level. Following creation of a lidar digital elevation model (DEM), geospatial analyses delineated morphologic attributes of 1,034 patch reefs (reef depth, basal area, height, volume, and topographic complexity). Morphometric analysis revealed two morphologically different populations of patch reefs associated with two distinct depth intervals above and below a water depth of 7.7 m. Compared to shallow reefs, the deep reefs were smaller in area and volume and showed no trend in topographic complexity relative to water depth. Shallow reefs were more variable in area and volume and became flatter and less topographically complex with decreasing water depth. The knoll-like morphology of deep reefs was interpreted as consistent with steady and relatively rapidly rising early Holocene sea level that restricted the lateral growth of reefs. The morphology of shallow 'pancake-shaped' reefs at the highest platform elevations was interpreted as consistent with fluctuating sea level during the late Holocene. Although the ultimate cause for the morphometric depth trends remains open to interpretation, these interpretations are compatible with a recent eustatic sea-level curve that hindcasts fluctuating late Holocene sea level. Thus it is suggested that the morphologic differences represent two stages of reef accretion that occurred during different sea-level conditions. ?? 2008 Springer-Verlag.

  14. Sequence stratigraphy and a revised sea-level curve for the Middle Devonian of eastern North America

    USGS Publications Warehouse

    Brett, Carlton E.; Baird, G.C.; Bartholomew, A.J.; DeSantis, M.K.; Ver Straeten, C.A.

    2011-01-01

    The well-exposed Middle Devonian rocks of the Appalachian foreland basin (Onondaga Formation; Hamilton Group, Tully Formation, and the Genesee Group of New York State) preserve one of the most detailed records of high-order sea-level oscillation cycles for this time period in the world. Detailed examination of coeval units in distal areas of the Appalachian Basin, as well as portions of the Michigan and Illinois basins, has revealed that the pattern of high-order sea-level oscillations documented in the New York-Pennsylvania section can be positively identified in all areas of eastern North America where coeval units are preserved. The persistence of the pattern of high-order sea-level cycles across such a wide geographic area suggests that these cycles are allocyclic in nature with primary control on deposition being eustatic sea-level oscillation, as opposed to autocylic controls, such as sediment supply, which would be more local in their manifestation. There is strong evidence from studies of cyclicity and spectral analysis that these cycles are also related to Milankovitch orbital variations, with the short and long-term eccentricity cycles (100. kyr and 405. kyr) being the dominant oscillations in many settings. Relative sea-level oscillations of tens of meters are likely and raise considerable issues about the driving mechanism, given that the Middle Devonian appears to record a greenhouse phase of Phanerozoic history. These new correlations lend strong support to a revised high-resolution sea-level oscillation curve for the Middle Devonian for the eastern portion of North America. Recognized third-order sequences are: Eif-1 lower Onondaga Formation, Eif-2: upper Onondaga and Union Springs formations; Eif-Giv: Oatka Creek Formation; Giv-1: Skaneateles, Giv-2: Ludlowville, Giv-3: lower Moscow, Giv-4: upper Moscow-lower Tully, and Giv-5: middle Tully-Geneseo formations. Thus, in contrast with the widely cited eustatic curve of Johnson et al. (1985), which

  15. Late Holocene Sea-Level Changes in French Polynesia, South-Central Pacific

    NASA Astrophysics Data System (ADS)

    Camoin, G.; Hallmann, N.; Eisenhauer, A.; Samankassou, E.; Milne, G. A.

    2013-12-01

    Camoin, G.1, Hallmann, N.1, Eisenhauer, A.2, Vella, C.1, Samankassou, E.3, Fietzke, J.2, Milne, G.A.4 1 Aix-Marseille Université, CNRS, IRD, CEREGE UM34, Europôle Méditerranéen de l'Arbois, BP80, 13545 Aix-en-Provence cedex 4, France 2 Helmholtz-Zentrum für Ozeanforschung GEOMAR, Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany 3 University of Geneva, Rue des Maraîchers 13, CH-1205 Geneva, Switzerland 4 University of Ottawa, Department of Earth Sciences, Ottawa, Ontario, K1N 6N5, Canada Knowledge of the timing and course of sea-level changes provides an essential framework for conceptual models aimed at understanding the dynamics of melting of large ice sheets and their effects on the isostasy of the Earth. The marked variability of local Holocene sea levels, responding both to ice-sheet unloading and the redistribution of water masses in the global ocean, demonstrates the need to constrain geophysical processes that include hydro-isostasy, equatorial ocean syphoning and tectonic movements affecting relative sea-level positions. A regional reconstruction of Late Holocene sea-level changes (i.e., the last 6,000 yrs) in French Polynesia is based on the accurate U-series dating of in situ sea-level indicators (coral colonies including microatolls; bivalves) and their precise vertical and horizontal GPS positioning in five atolls (Fakarava, Hao, Manihi, Rangiroa, Tikehau) from the Tuamotu Archipelago and six high islands (Bora Bora, Mangareva, Maupiti, Moorea, Raivavae, Rurutu) from the Society, Gambier and Austral Archipelagos. These islands provide the opportunity to reconstruct accurately Late Holocene sea-level changes that are well-suited to estimate eustatic and isostatic changes because : 1) they exhibit unique coral reef records including valuable sea-level indicators, such as corals and bivalves in growth position, emerged coral conglomerates and beachrocks, 2) their subsidence rates are negligible for the Late Holocene period, thus excluding any tectonic

  16. Sea-level changes over the past 6,000 years in the Society and Tuamotu Islands, French Polynesia

    NASA Astrophysics Data System (ADS)

    Hallmann, N.; Camoin, G.; Eisenhauer, A.; Vella, C.; Samankassou, E.; Fietzke, J.; Milne, G. A.

    2013-12-01

    Tropical coral reefs are unique recorders of sea-level and environmental changes. They are therefore of pivotal importance to resolving the rates of millennial-scale eustatic changes, to clarifying the mechanisms that drive glacial-interglacial cycles and to constraining geophysical models. A detailed regional study of Late Holocene (i.e., the past 6,000 years) relative sea-level changes is based on coral reef records of two high islands from the Society Islands (Bora Bora, Moorea) and two atolls from the Tuamotu Archipelago (Rangiroa, Tikehau), French Polynesia, South-Central Pacific. Different sea-level indicators, such as in situ coral colonies, bivalves and exposed coral conglomerates, were used in order to reconstruct relative sea-level changes. A special attention has been given to microatolls which are circular coral colonies that grow predominantly laterally as their upward growth is constrained by the water level, thus providing an accurate record of the low-tide level. The reconstruction of sea-level changes has been based on the accurate dating (U/Th (MC-ICPMS) dating with a 2σ error of 3-36 years) of pristine coral and bivalve samples and the precise measurement of their position (especially altitude) via GPS (vertical and horizontal precision of 1-3 cm and a few millimetres, respectively). Former studies have reported that sea level in French Polynesia was approximately 1 m higher than present between 5,000 and 1,250 yrs BP and that a highstand was reached between 2,000 and 1,500 yrs BP (Pirazzoli and Montaggioni, 1988) and persisted until 1,200 yrs BP in the Tuamotu Archipelago (Pirazzoli and Montaggioni, 1986). In contrast to these former studies, our study reveals that sea level reached its present level at around 5,000 yrs BP and continued to rise from at least 4,951 to 2,535 yrs BP when it was at least 1.3 m above the present level. These results will be integrated in a regional study of Late Holocene sea-level changes in various islands from

  17. Contribution of climate-driven change in continental water storage to recent sea-level rise

    USGS Publications Warehouse

    Milly, P.C.D.; Cazenave, A.; Gennero, M.C.

    2003-01-01

    Using a global model of continental water balance, forced by interannual variations in precipitation and near-surface atmospheric temperature for the period 1981-1998, we estimate the sea-level changes associated with climate-driven changes in storage of water as snowpack, soil water, and ground water; storage in ice sheets and large lakes is not considered. The 1981-1998 trend is estimated to be 0.12 mm/yr, and substantial interannual fluctuations are inferred; for 1993-1998, the trend is 0.25 mm/yr. At the decadal time scale, the terrestrial contribution to eustatic (i.e., induced by mass exchange) sea-level rise is significantly smaller than the estimated steric (i.e., induced by density changes) trend for the same period, but is not negligibly small. In the model the sea-level rise is driven mainly by a downtrend in continental precipitation during the study period, which we believe was generated by natural variability in the climate system.

  18. Eustatic and tectonic control on localization of porosity and permeability, Mid-Permian, Bighorn Basin, Wyoming

    SciTech Connect

    Simmons, S.P.; Scholle, P.A. )

    1990-05-01

    The Goose Egg Formation of the northeastern Bighorn basin was deposited in an arid shoreline (sabkha) environment during a time of global cyclic sea level variations and local tectonic uplift Eustatic sea level lows are represented by terrestrial red beds (seals), whereas highs resulted in the deposition of supratidal to shallow subtidal carbonates (reservoirs). Pennsylvanian and Permian differential uplift along the present basin margin localized a broken chain of barrier islands and shoals during deposition of the Ervay and earlier carbonate members, as recognized in outcrop at Sheep and Little Sheep Mountain anticlines. The Ervay Member on these paleohighs is typified by fenestral dolomite, containing abundant tepees and pisoids. This fabric is interpreted to have folded in the highest intertidal to supratidal sabkha environment which developed on the leeward shores of these islands. The fenestral carbonates grade basinward (westward) into narrow bioclastic grainstone beach deposits and then to open-shelf fossiliferous packstones and wackestone. To the east lie laminated lagoonal micritic limestones and dolomites. Outcrop and core study has shown the fenestral facies to be limited to areas coincident with present-day basin margin anticlines. Not only are these the locations of the most porous facies, but tight Laramide folding of the Goose Egg carbonates resulted in pervasive fracturing and thus very high permeabilities in the same structures. The close association of Laramide folds and productive Permian carbonate horizons in the northeast Bighorn basin could well be characteristic for other yet to be explored structures along the basin-margin trend.

  19. Eustatic and structural control of submarine-fan sedimentation, Conception fan, Santa Barbara basin, California

    SciTech Connect

    Thor, D.R.

    1984-04-01

    Eustatic sea level lows provide an opportunity for submarine-fan development; topography and structure, however, can control depositional-sequence geometry. Analysis of high-resolution seismic data provides a basis to evaluate to the evolution and geometry of the Pleistocene-Holocene Conception fan. The fan formed in the restricted, tectonically active Santo Barbara basin. It consists of 4 vertically stacked depositional sequences, each bounded by nondepositional unconformities. The unconformities are defined by seismic-sequence boundaries and were formed during sea-level falls that are related to Pleistocene glacioeustatic changes. Each depositional sequence consists of lowstand, sandrich facies (fan channel, levee, and lobe) topped by highstand, mud-rich facies. The geometry of the depositional sequences tends to be rectilinear, not arcuate, because lateral progradation is restricted by topographically high structures. The modern fan surface and the Holocene depositional sequence provide a good analog for the older, underlying depositional sequences. The fan surface is characterized by 4 main channels, 2 of which head into submarine canyons incised into the shelf. Submarine canyons that fed the other 2 channels are now filled and have no topographic expression. In addition, numerous partially buried channel segments occur in the interchannel areas. The Holocene depositional sequence consists of lenticular and sheet-drape deposits interpreted to be channel, levee, and lobe facies. The facies geometry suggests that Mutti's topographic compensation, channel migration, and avulsion were typical processes on Conception fan.

  20. Common Era Sea-Level Change

    NASA Astrophysics Data System (ADS)

    Horton, B.; Kemp, A.; Kopp, R. E., III

    2014-12-01

    The Atlantic coast of North America provides a sedimentary record of Common Era sea levels with the resolution to identify the mechanisms that cause spatial variability in sea-level rise. This coast has a small tidal range, improving the precision of sea-level reconstructions. Coastal subsidence (from glacial isostatic adjustment, GIA) creates accommodation space that is filled by salt-marsh peat and preserves accurate and precise sea-level indicators and abundant material for radiocarbon dating. In addition, the western North Atlantic Ocean is sensitive to spatial variability in sea-level change, because of static equilibrium effects from melting of the Greenland Ice Sheet, ocean circulation and wind-driven variability in the Gulf Stream and GIA induced land-level change from ongoing collapse of Laurentide forbuldge. We reveal three distinct patters in sea-level during the Common Era along the North American Atlantic coast, likely linked to wind-driven changes in the Gulf Stream: (1) Florida, sea level is essentially flat, with the record dominated by long-term geological processes; (2) North Carolina, sea level falls to a minimum near the beginning of the second millennium, climbing to an early Little Ice Age maximum in the fifteenth century, and then declining through most of the nineteenth century; and (3) New Jersey, a sea-level maximum around 900 CE, a sea-level minimum around 1500 CE, and a long-term sea-level rise through the second half of the second millennium. We combine the salt-marsh data from North American Atlantic coast with tide-gauge records and lower resolution proxies from the northern and southern hemispheres. We apply a noisy-input Gaussian process spatio-temporal modeling framework, which identifies a long-term falling global mean sea-level (GMSL), interrupted in the middle of the 19th century by an acceleration yielding a 20th century rate of rise extremely likely (probability P = 0:95) faster than any previous century in the Common Era.

  1. Sea-level rise impacts on scour at coastal bridges in the southeastern United States

    NASA Astrophysics Data System (ADS)

    Froehlich, D.

    2003-04-01

    Sea level, which has risen by 10 to 20 cm (4 to 8 inches) in the past century along most of the US coastline, is projected to rise an additional 48 cm (19 inches) by 2100, with a possible range of 13 cm to 95 cm (26 to 37 inches). Eustatic increases in sea level are being caused largely by melting glaciers and ice sheets on land, and thermal expansion of ocean water. Sea level rise will continue to accelerate beyond 2100 as a result of the great amount of time needed for oceans and ice sheets to approach equilibrium under the long-term perturbations anticipated with climate change. Tropical storms, hurricanes, typhoons, and similar extreme atmospheric phenomena along the southeastern coast of the US generate high winds that in turn create large waves and currents. Resulting storm surges can temporarily raise water levels by as much as 23 feet (7 meters) above normal. Although these events are sporadic, they are a primary cause of scour at bridges along most of the US coastline. Even if storm magnitudes and frequencies do not change as a result of global warming, an important impact of future storms, whether tropical or extratropical, will be their superposition on a rising sea level. Thus sea-level rise will increase impacts to the coast by a storm of a given magnitude by increasing the baseline water level for extreme storms. Because many coastal bridges were designed to withstand erosion produced by storm surges having 1 percent annual chance of occurrence (that is, 100-year storm surge), as sea levels increase the statistics used to design these structures changes. For example, a 50-year storm surge following an increase in sea level could scour a bridge as severely as would the current 100-year storm surge. Impacts of rising sea levels on scour at coastal bridges in the southeastern US are illustrated by an analysis of the Cape Fear River estuary system in North Carolina. A numerical model of fully-coupled flow and sediment transport in open channels was used

  2. Reconstruction of Late Holocene sea-level change in French Polynesia, South Pacific, based on coral reef records

    NASA Astrophysics Data System (ADS)

    Hallmann, Nadine; Camoin, Gilbert; Eisenhauer, Anton; Vella, Claude

    2013-04-01

    Fossil reefs provide valuable sea-level indicators, which help to improve the understanding of past sea-level fluctuations and the prediction of future changes. Recent sea-level changes were reconstructed from emerged reef platforms of two high islands from the Society Islands (Bora Bora, Moorea) and two atolls from the Tuamotu Archipelago (Rangiroa, Tikehau), French Polynesia. These mid-ocean islands can be regarded as tectonically stable for the past few thousand years. Therefore, they are well suited for sea-level studies because they register Holocene eustatic changes, which are not overprinted by tectonic changes. Furthermore, the study sites are located distant from former ice sheets (far field location), which reduces the influence of the glacio-isostatic rebound. Several sea-level indicators, such as in situ coral colonies, including coral microatolls (Porites sp.), bivalves (mainly Tridacna sp.), conglomerates, beachrock, and sediments were analyzed in order to reconstruct Late Holocene relative sea-level changes. Microatolls are discoid corals that develop laterally when upward growth is limited by sea-level. Therefore, they are very accurate recorders of past sea-level. This study provides a detailed sea-level history for French Polynesia using high-precision U/Th (TIMS) dating and GPS measurements with a vertical and horizontal precision of 1-3 cm and a few millimetres, respectively. All samples were analyzed by X-ray diffraction and examined petrographically to exclude diagenetically altered material. The Holocene mean sea level in French Polynesia was thought to have been higher than present (+0.8/+1.0 m) between 5000 and 1250 yr BP, reached a highstand between 2000 and 1500 yr BP and then decreased to the present level (Pirazzoli and Montaggioni, 1988). The highstand has been reported until 1200 yr BP in the Tuamotu Archipelago (Pirazzoli and Montaggioni, 1986). However, sea-level indicators analyzed in this study reveal a highstand of at least 1.5 m

  3. Global sea level linked to global temperature

    PubMed Central

    Vermeer, Martin; Rahmstorf, Stefan

    2009-01-01

    We propose a simple relationship linking global sea-level variations on time scales of decades to centuries to global mean temperature. This relationship is tested on synthetic data from a global climate model for the past millennium and the next century. When applied to observed data of sea level and temperature for 1880–2000, and taking into account known anthropogenic hydrologic contributions to sea level, the correlation is >0.99, explaining 98% of the variance. For future global temperature scenarios of the Intergovernmental Panel on Climate Change's Fourth Assessment Report, the relationship projects a sea-level rise ranging from 75 to 190 cm for the period 1990–2100. PMID:19995972

  4. Climate Adaptation and Sea Level Rise

    EPA Pesticide Factsheets

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

  5. Annotated Bibliography of Relative Sea Level Change

    DTIC Science & Technology

    1991-09-01

    contribution, and--future sea-level scenarios. If an accelerated rise of sea level occurs as predicted, coastal communities will be faced with deciding the...Moreover, seismic sequence analysis in ne.. u.plo- ration areas allow for reliable predictions of geologic age ahead of drilli.g and facilitate...comparable age suggest a strong seaward tilt of the outer continental shelf. The outer -shelf over the Baltimore Canyon trough geosyncline has

  6. Future high sea levels in south Sweden

    SciTech Connect

    Blomgren, S.H.; Hanson, H.

    1997-12-31

    An estimation of future mean high water levels in Oeresund and the southwest Baltic Sea is presented together with a discussion of probable consequences for Falsterbo Peninsula, a trumpet-shaped sandy formation of some 25 km{sup 2} size situated in the very southwest corner of Sweden. A literature review coupled with sea-level measurements and observations made in the area every four hours since October 1945 are given and comprise the base for the present analysis.

  7. Glacier Contributions to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Gardner, A. S.; Cogley, J. G.; Moholdt, G.; Wouters, B.; Wiese, D. N.

    2015-12-01

    Global mean sea level is rising in response to two primary factors: warming oceans and diminishing glaciers and ice sheets. If melted completely, glaciers would raise sea levels by half a meter, much less than that the 80 meters or so that would result from total melt of the massive Greenland and Antarctic ice sheets. That is why glacier contributions to sea level rise have been less studied, allowing estimates of to vary widely. Glacier contributions to sea level change are challenging to quantify as they are broadly distributed, located in remote and poorly accessible high latitude and high altitude regions, and ground observations are sparse. Advances in satellite altimetry (ICESat) and gravimetry (GRACE) have helped, but they also have their own challenges and limitations. Here we present an updated (2003-2014) synthesis of multiple techniques adapted for varying regions to show that rates of glacier loss change little between the 2003-2009 and 2003-2014 periods, accounting for roughly one third of global mean sea level rise. Over the next century and beyond glaciers are expected to continue to contribute substantial volumes of water to the world's oceans, motivating continued study of how glaciers respond to climate change that will improve projections of future sea levels.

  8. Development of the Bulgarian Sea Level Service

    NASA Astrophysics Data System (ADS)

    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

  9. Tritium level along Romanian Black Sea Coast

    SciTech Connect

    Varlam, C.; Stefanescu, I.; Popescu, I.; Faurescu, I.

    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)

  10. Shallow stratigraphy and sedimentation history during high-frequency sea-level changes on the central California shelf

    USGS Publications Warehouse

    Grossman, E.E.; Eittreim, S.L.; Field, M.E.; Wong, F.L.

    2006-01-01

    Analyses of high-resolution seismic-reflection data and sediment cores indicate that an extensive sediment deposit on the central California continental shelf is comprised of several late-Pleistocene to Holocene age facies. Offshore of the littoral zone, in water depths of 30-90 m, a 3-6 m thick veneer of fine sediment referred to as the mid-shelf mudbelt has formed along 50-100 km of the coast. The mudbelt drapes a parasequence characterized by prograding clinoforms that in places overlies a 1-3 m thick basal transgressive lag deposit. These facies overlie a prominent erosional unconformity that extends from the shore to the outer shelf. Eighteen calibrated 14CAMS ages of marine molluscs and terrestrial wood detritus sampled in cores range 15,800 yr BP to modern indicating a postglacial age for these sediments (one >55,000 yr BP represents relict sand). We model accumulation of these facies using (1) the topography of the underlying erosional unconformity interpreted from seismic reflection profiles, (2) observed sediment facies (grain size) distribution across the shelf (a proxy for wave/current sediment partitioning), and published estimates of (3) eustatic sea-level history, and (4) regional tectonics. Our model and data indicate that deposition of the transgressive lag began during early, slow postglacial sea-level rise and that a notable change in depositional environment occurred across an area of more than 200 km2 of the outer shelf likely in response to abrupt drowning during Meltwater Pulse 1B (11,500 yr BP). We propose that rapid progradation of clinoforms may have occurred during transgression because of the unique interaction of modest rates of sediment input and tectonic uplift, variable rates of eustatic sea-level rise and a complex stepped antecedent topography.

  11. Tectono-eustatic controls on carbonate platform development, Permian basin outcrop-subsurface

    SciTech Connect

    Sarg, J.F.; Romine, K.; Vail, P.R.

    1987-05-01

    Integration of seismic stratigraphic concepts, detailed field studies, and geohistory analysis provides powerful interpretation leverage for deciphering the geologic history of the Permian carbonate platform complexes. The structural history of the Permian basin during the Permian shows two subsidence cycles of 10 to 20 m.y. duration. These subsidence cycles played a major role in the long-term (millions to tens of millions of years) development of the Permian carbonate platforms. During periods of relatively rapid subsidence, aggradation was dominant; during times of slow subsidence, major basinward platform progradation occurred. Superimposed on the long-term tectonic cycles are a series of third-order eustatic cycles (0.5-3 m.y.) which controlled development of 23 depositional sequences. Each sequence is composed of three depositional systems tracts: (1) a lower basin-restricted wedge interpreted to have been deposited during a relative fall and lowstand of sea level; (2) a transgressive systems tract of variable thickness; and (3) an upper aggradational to progradational carbonate platform system interpreted to have been deposited during a relative highstand in sea level. The lowstand systems tracts are composed dominantly of quartz sandstone, commonly intercalated with carbonate debris beds at the toe-of-slope. Two highstand depositional styles are differentiated here: (1) a keep-up system which maintains pace with periodic rises in relative sea level and displays a mounded-oblique stratal geometry at the platform margin and (2) a catch-up system which represents a relatively slow rate of accumulation and displays a sigmoid profile at the platform margin. Sequence boundaries display erosional truncation (subaerial on shelf or at shelf edge; subaqueous on slope) and/or subaerial exposure.

  12. Sea Level Rise Impacts On Infrastructure Vulnerability

    NASA Astrophysics Data System (ADS)

    Pasqualini, D.; Mccown, A. W.; Backhaus, S.; Urban, N. M.

    2015-12-01

    Increase of global sea level is one of the potential consequences of climate change and represents a threat for the U.S.A coastal regions, which are highly populated and home of critical infrastructures. The potential danger caused by sea level rise may escalate if sea level rise is coupled with an increase in frequency and intensity of storms that may strike these regions. These coupled threats present a clear risk to population and critical infrastructure and are concerns for Federal, State, and particularly local response and recovery planners. Understanding the effect of sea level rise on the risk to critical infrastructure is crucial for long planning and for mitigating potential damages. In this work we quantify how infrastructure vulnerability to a range of storms changes due to an increase of sea level. Our study focuses on the Norfolk area of the U.S.A. We assess the direct damage of drinking water and wastewater facilities and the power sector caused by a distribution of synthetic hurricanes. In addition, our analysis estimates indirect consequences of these damages on population and economic activities accounting also for interdependencies across infrastructures. While projections unanimously indicate an increase in the rate of sea level rise, the scientific community does not agree on the size of this rate. Our risk assessment accounts for this uncertainty simulating a distribution of sea level rise for a specific climate scenario. Using our impact assessment results and assuming an increase of future hurricanes frequencies and intensities, we also estimate the expected benefits for critical infrastructure.

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

    NASA Astrophysics Data System (ADS)

    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

  14. Upper Limit for Regional Sea Level Projections

    NASA Astrophysics Data System (ADS)

    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.

  15. Sea level and diagenesis: a case study on Pleistocene beaches, Whalebone Bay, Bermuda

    NASA Astrophysics Data System (ADS)

    Vollbrecht, R.; Meischner, D.

    1993-07-01

    Pleistocene fluctuations of sea level have left marine and aeolian limestones intercalated with glacial red soils on the Bermuda Carbonate Platform (Atlantic, 64°50'W, 32°20'N). Successive eustatic highstands of similar amplitude drowned the tectonically stable platform and piled up similar sets of sediments. Up to three Pleistocene beaches are stacked in shorelines sections. Post-depositional diagenetic histories of these beaches can be linked to repeated changes in sea level and pore waters. This paper presents field evidence and petrographic results (microscope, X-ray, cathodoluminescence, SEMEDAX) for the diagenetic histories of two superimposed Pleistocene beaches in Whalebone Bay, Bermuda North Shore. The younger beach was deposited during isotopic stage 5e, about 120 ka ago. The age of the older beach may be isotopic stage 9 or older. Diagenesis drastically altered the older beach before the stage 5e transgression. Primary high-Mg calcite (HMC) and aragonite were no longer present. Marine skeletal grains were instead leached or recrystallized to low-Mg calcite (LMC). Primary and secondary pore space were largely reduced by LMC cement. Lines of needle relics reminiscent of marine aragonite cement occur as inclusions within syntaxial rim cements around echinoderm grains, indicating that a marine influence had at least once interrupted this period of freshwater alteration. Finally, before the rocks became buried by the sediments of the younger beach, a crust of marine, bladed HMC cement was precipitated throughout the pore space. The younger beach consists of skeletal grains that are, apart from the effects of non-selective dissolution, essentially unaltered. The sediments are only weakly lithified by cryptocrystalline LMC showing an alveolar texture, tangential fibres and other features characteristic of calichification. A younger post-depositional marine influence is not recorded. These results suggest that, under favourable conditions, diagenetic processes

  16. Contribution of mountain glaciers and ice caps to sea-level rise

    NASA Astrophysics Data System (ADS)

    Hock, R. M.; de Woul, M.; Radic, V.; Dyurgerov, M.

    2009-12-01

    Mountain glaciers and ice caps (MG&IC) have been identified as primary source of eustatic sea level rise, ahead of the ice sheets, during recent decades. The Intergovernmental Panel on Climate Change (IPCC) estimates that the sum of all contributions to sea-level rise for the period 1961-2004 was 1.1± 0.5 mm a-1, leaving 0.7±0.7 of the 1.8±0.5 mm a-1 observed sea-level rise unexplained. Here, we compute the global surface mass balance of all mountain glaciers and ice caps and find that part of this much-discussed gap can be attributed to a larger contribution than previously assumed from mass loss of MG&IC, especially those around the Antarctic Peninsula. We find a global surface mass loss of all MG&IC of 0.79±0.34 mm a-1 sea-level equivalent compared to IPCC’s 0.50±0.18 mm a-1. The Antarctic MG&IC contributed 28% of the global estimate due to exceptional warming around the Antarctic Peninsula and high mass-balance sensitivities to temperature similar to those we find in maritime Iceland, Patagonia and Alaska. Our results highlight the role of the MG&IC around the Antarctic Peninsula where climate is distinctly different from the cold conditions of the ice sheet, and large mass balance sensitivities to temperature, exceptional warming and large area combine to yield large potential for glacier mass loss. We emphasize an urgent need for improved glacier inventory and in-situ mass balance data from this region especially in light of recently accelerated mass loss from MG&IC.

  17. Estimating the sources of global sea level rise with data assimilation techniques.

    PubMed

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

    2013-02-26

    A rapidly melting ice sheet produces a distinctive geometry, or fingerprint, of sea level (SL) change. Thus, a network of SL observations may, in principle, be used to infer sources of meltwater flux. We outline a formalism, based on a modified Kalman smoother, for using tide gauge observations to estimate the individual sources of global SL change. We also report on a series of detection experiments based on synthetic SL data that explore the feasibility of extracting source information from SL records. The Kalman smoother technique iteratively calculates the maximum-likelihood estimate of Greenland ice sheet (GIS) and West Antarctic ice sheet (WAIS) melt at each time step, and it accommodates data gaps while also permitting the estimation of nonlinear trends. Our synthetic tests indicate that when all tide gauge records are used in the analysis, it should be possible to estimate GIS and WAIS melt rates greater than ∼0.3 and ∼0.4 mm of equivalent eustatic sea level rise per year, respectively. We have also implemented a multimodel Kalman filter that allows us to account rigorously for additional contributions to SL changes and their associated uncertainty. The multimodel filter uses 72 glacial isostatic adjustment models and 3 ocean dynamic models to estimate the most likely models for these processes given the synthetic observations. We conclude that our modified Kalman smoother procedure provides a powerful method for inferring melt rates in a warming world.

  18. Estimating the sources of global sea level rise with data assimilation techniques

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    A rapidly melting ice sheet produces a distinctive geometry, or fingerprint, of sea level (SL) change. Thus, a network of SL observations may, in principle, be used to infer sources of meltwater flux. We outline a formalism, based on a modified Kalman smoother, for using tide gauge observations to estimate the individual sources of global SL change. We also report on a series of detection experiments based on synthetic SL data that explore the feasibility of extracting source information from SL records. The Kalman smoother technique iteratively calculates the maximum-likelihood estimate of Greenland ice sheet (GIS) and West Antarctic ice sheet (WAIS) melt at each time step, and it accommodates data gaps while also permitting the estimation of nonlinear trends. Our synthetic tests indicate that when all tide gauge records are used in the analysis, it should be possible to estimate GIS and WAIS melt rates greater than ∼0.3 and ∼0.4 mm of equivalent eustatic sea level rise per year, respectively. We have also implemented a multimodel Kalman filter that allows us to account rigorously for additional contributions to SL changes and their associated uncertainty. The multimodel filter uses 72 glacial isostatic adjustment models and 3 ocean dynamic models to estimate the most likely models for these processes given the synthetic observations. We conclude that our modified Kalman smoother procedure provides a powerful method for inferring melt rates in a warming world.

  19. Tectonic and glacio-eustatic influences on Late Cambrian-Early Devonian first-order stratigraphic and faunal suites in the Great Basin

    SciTech Connect

    Berry, W.B.N. )

    1991-02-01

    The Late Cambrian to middle Devonian stratigraphic and faunal record i the western United States may be divided into at least five first-order or primary depositional cycles delimited by tectonically controlled sea level changes. These tectonically controlled sea level changes essentially are changes in rate of platform subsidence. Rate of platform subsidence is reflected in changes in the succession of depositional environments. Tectonically controlled sea level changes are reflected in the succession of faunas as well as in the depositional environment record. The primary rate of subsidence-related sea level changes took place at the following times: latest Cambrian, latest Ibexian (Early Ordovician), and late Early Devonian. A prominent set of glacio-eustatic sea level changes occurred in the latest Ordovician-earliest Silurian. That glacial interval was one in which significant mass mortalities and subsequent re-radiations took place among marine invertebrates. Although the boundaries of the first-order cycles, both in the stratigraphic depositional cycles appear to be diachronous across the Great Basin, the rock suites comprising the cycles are delimited clearly. Second-order cycles may be recognized within the first-order cycles, both in the stratigraphic and faunal record. The second-order cycles also reflect sea level changes. Major oceanic surface water currents were deflected around plate and related platform margins during intervals of regression from the platform, enhancing upwelling along the plate margins during such intervals.

  20. 3000 Years of Sea Level Change.

    NASA Astrophysics Data System (ADS)

    Tanner, William F.

    1992-03-01

    Sea level change is generally taken to indicate climate change, and may be more nearly global than what we perceive to be climate change. Close to the beach, even a small sea level change (such as 1-3 m) produces important changes in local depositional conditions. This effect can be deduced from a study of properly selected beach deposits.Various measures of beach-sand grain size indicate conditions of deposition. The best of these parameters is the kurtosis; it is a reliable indicator of surf-zone wave energy density. An abrupt energy-level shift, after centuries with little change, indicates sea level rise or drop. Kurtosis, within stated limits, shows this.Beach ridge systems (successive, distinct old beach deposits) span the last several thousand years. A sequence of sand samples across such a deposit provides grain-size evidence for alternating high and low sea level. Changes were 1 to 3 m vertically, and took place at rates of about 1 ern yr1. There were at least seven such events in the last 3000 years.The two most recent changes were the drop and subsequent rise that marked the Little Ice Age (starting about 1200 A.D.). One cannot say, from these data, that the planet has come fully out of the Little ice Age. Predictions about what sea level will do in the near future should be based on the many small changes (1 to 3 m) in the last few thousand years, rather than on the arbitrary, fictitious, and unrealistic absolute sea level that appears to underlie various popular forecasts.

  1. Extended Late Pleistocene Sea Level Record

    NASA Astrophysics Data System (ADS)

    Fairbanks, R. G.; Cao, L.; Mortlock, R. A.

    2006-12-01

    Several hundred new closed system 230Th/234U and radiocarbon dates and the addition of more cores and coral samples from the islands of Barbados, Kiritimati and Araki contribute to an enhanced sea level record for the late Pleistocene ranging from the present to 240,000 yrs BP. Application of more rigorous sample screening criteria, including redundant 231Pa/235U dates have resulted in more closed system ages and better sea level resolution. In addition, a multibeam survey has mapped an extensive glacial lowstand reef on a ridge south of Barbados that is capped by a set of pinnacle reefs that grew during the early deglaciation. Among our new observations, the more detailed Barbados sea level record now resolves a Younger Dryas still- stand and a sea level drop between 16,140 and 14,690, overlapping the timing of H1 by some age estimates. The coral ages bracketing melt water pulse 1A have been further refined to 14,082 +/- 28 yrs BP and 13,632 +/- 32 yrs BP (2-sigma). The Isotope Stage 3 interstadial ended with sea level near 87.5 meters below present at 29,500 years ago before dropping to full glacial levels. The last glacial sea level lowstand began as early as 26,000 yrs BP. Extensive dating of Marine Isotope Stage 3 interstadial reefs on the islands of Araki and Barbados have added considerable resolution to this time interval and reliably bracket lowstand intervals separating the interstadials. A new diagenesis model has improved our prospecting success for closed system ages from older reefs and added some critical dates to the sparse closed-system data set for MIS-5 and MIS-7 high stand reefs..

  2. Visualizing Sea Level Rise with Augmented Reality

    NASA Astrophysics Data System (ADS)

    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.

  3. Sea Level Rise in Santa Clara County

    NASA Technical Reports Server (NTRS)

    Milesi, Cristina

    2005-01-01

    Presentation by Cristina Milesi, First Author, NASA Ames Research Center, Moffett Field, CA at the "Meeting the Challenge of Sea Level Rise in Santa Clara County" on June 19, 2005 Santa Clara County, bordering with the southern portion of the San Francisco Bay, is highly vulnerable to flooding and to sea level rise (SLR). In this presentation, the latest sea level rise projections for the San Francisco Bay will be discussed in the context of extreme water height frequency and extent of flooding vulnerability. I will also present preliminary estimations of levee requirements and possible mitigation through tidal restoration of existing salt ponds. The examples will draw mainly from the work done by the NASA Climate Adaptation Science Investigators at NASA Ames.

  4. The Sea Level Fingerprints of Global Change

    NASA Astrophysics Data System (ADS)

    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.

  5. Late Quaternary climatic events and sea-level changes recorded by turbidite activity, Dakar Canyon, NW Africa

    NASA Astrophysics Data System (ADS)

    Pierau, Roberto; Hanebuth, Till J. J.; Krastel, Sebastian; Henrich, Rüdiger

    2010-03-01

    The relationship of sea-level changes and short-term climatic changes with turbidite deposition is poorly documented, although the mechanisms of gravity-driven sediment transport in submarine canyons during sea-level changes have been reported from many regions. This study focuses on the activity of the Dakar Canyon off southern Senegal in response to major glacial/interglacial sea-level shifts and variability in the NW-African continental climate. The sedimentary record from the canyon allows us to determine the timing of turbidite events and, on the basis of XRF-scanning element data, we have identified the climate signal at a sub-millennial time scale from the surrounding hemipelagic sediments. Over the late Quaternary the highest frequency in turbidite activity in the Dakar Canyon is confined to major climatic terminations when remobilisation of sediments from the shelf was triggered by the eustatic sea-level rise. However, episodic turbidite events coincide with the timing of Heinrich events in the North Atlantic. During these times continental climate has changed rapidly, with evidence for higher dust supply over NW Africa which has fed turbidity currents. Increased aridity and enhanced wind strength in the southern Saharan-Sahelian zone may have provided a source for this dust.

  6. Sea level trends and interannual variability in the Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Torres, R.; Tsimplis, M.

    2012-04-01

    Sea level trends and interannual variability has been investigated in the Caribbean Sea using altimetry and tide gauge time series from 19 stations. Relative sea level trends range between -2.0 and 10.7 mm/y depending on the length of the available record. Records from stations longer than 40 years converge toward values between 1.2 - 5.2 mm/yr, still a significant range which in some stations is less and in some other significantly larger than the global average. The longest station, Cristobal (102 years) shows a trend of 1.9 mm/yr and, in addition a significant acceleration of 1.6±0.3 mm/y/cy. The observed sea level trends are not affected by the atmospheric pressure effect, within the levels of significance. They are also the same (within the levels of significance) at all seasons. Altimetry shows trends (over 18 years of data) with values up to 5.2 mm/y. In some areas the values are statistically insignificant, but at no areas statistically significant negative values are found. Steric trends from the top 800 m (over the period of altimetric observations) have a basin average trend of 1 mm/y, but it shows large spatial variability with negative trends of -7 mm/y in the Yucatan Basin and positive trends up to 4.9 mm/y in the Venezuela Basin. Decadal trends were found to vary significantly at tide-gauge records as well as altimetric and steric measurements. We further explore the residual interannual variability by comparison with surface wind and climatic indices. This analysis is supported by the Lloyd's Register Trust Fund project Marine Extremes.

  7. Superstatistical analysis of sea-level fluctuations

    NASA Astrophysics Data System (ADS)

    Rabassa, Pau; Beck, Christian

    2015-01-01

    We perform a statistical analysis of measured time series of sea levels at various coastal locations in the UK, measured at time differences of 15 min over the past 20 years. When the astronomical tide and other deterministic components are removed from the record, a stochastic signal corresponding to the meteorological component remains, and this is well-described by a superstatistical model. We do various tests on the measured time series, and compare the data at 5 different UK locations. Overall the χ2-superstatistics is best suitable to describe the data, in particular when one looks at the dynamics of sea-level differences on short time scales.

  8. Sea Level Variability in the Mediterranean

    NASA Astrophysics Data System (ADS)

    Zerbini, S.; Bruni, S.; del Conte, S.; Errico, M.; Petracca, F.; Prati, C.; Raicich, F.; Santi, E.

    2015-12-01

    Tide gauges measure local sea-level relative to a benchmark on land, therefore the interpretation of these measurements can be limited by the lack of appropriate knowledge of vertical crustal motions. The oldest sea-level records date back to the 18th century; these observations are the only centuries-old data source enabling the estimate of historical sea-level trends/variations. In general, tide gauge benchmarks were not frequently levelled, except in those stations where natural and/or anthropogenic subsidence was a major concern. However, in most cases, it is difficult to retrieve the historical geodetic levelling data. Space geodetic techniques, such as GNSS, Doris and InSAR are now providing measurements on a time and space-continuous basis, giving rise to a large amount of different data sets. The vertical motions resulting from the various analyses need to be compared and best exploited for achieving reliable estimates of sea level variations. In the Mediterranean area, there are a few centennial tide gauge records; our study focuses, in particular, on the Italian time series of Genoa, Marina di Ravenna, Venice and Trieste. Two of these stations, Marina di Ravenna and Venice, are affected by both natural and anthropogenic subsidence, the latter was particularly intense during a few decades of the 20th century because of ground fluids withdrawal. We have retrieved levelling data of benchmarks at and/or close to the tide gauges from the end of 1800 and, for the last couple of decades, also GPS and InSAR height time series in close proximity of the stations. By using an ensemble of these data, modelling of the long-period non-linear behavior of subsidence was successfully accomplished. After removal of the land vertical motions, the linear long period sea-level rates of all stations are in excellent agreement. Over the last two decades, the tide gauge rates were also compared with those obtained by satellite radar altimetry data.

  9. Aptian-Albian sea level history from Guyots in the western Pacific

    NASA Astrophysics Data System (ADS)

    RöHl, Ursula; Ogg, James G.

    1996-10-01

    Relative sea level fluctuations are an important control on patterns of sedimentation on continental margins and provide a valuable tool for regional correlations. One of the main objectives of combined Ocean Drilling Program Legs 143 and 144 was drilling the thick carbonate caps of a suite of seamounts, called guyots, scattered over the northwestern Pacific. The array of drowned Cretaceous banks includes four carbonate banks of Aptian-Albian age. These particular carbonate banks display emergent surfaces if regional sea level falls faster than the rate of guyot subsidence, or intervals of condensed parasequences and well-cemented peritidal crypto-algal flats if the rate of sea level fall is slightly less than guyot subsidence. Rapid rises of sea level following these sequence boundaries are recorded as drowning of the emergent horizons or as pronounced deepening of facies. The cored lithologies and downhole geophysical and geochemical logs were used to identify depositional sequences and surfaces of exceptional shallowing or deepening. A combination of biostratigraphic datums, carbon and strontium isotope curves, relative magnitude of surfaces of emergence, relative thicknesses of depositional sequences, sea level events, and counts of upward shallowing cycles or parasequences were used to correlate sequences among the four sites. After compensating for thermal subsidence rates at each guyot, an identical pattern of major Aptian-Albian eustatic sea level events is evident throughout this large portion of the Pacific Ocean. There are approximately 12 Aptian and 12 Albian significant sequence boundaries, of which a third were associated with major episodes of emergence. When these events are compared with Aptian-Albian relative sea level changes observed in European shelf successions, the major sequence boundaries and transgressive surges can be easily correlated, and it appears that both regions also display the same number of minor events. Therefore we can apply

  10. Monthly variations of the Caspian sea level and solar activity.

    NASA Astrophysics Data System (ADS)

    Romanchuk, P. R.; Pasechnik, M. N.

    The connection between 11-year cycle of solar activity and the Caspian sea level is investigated. Seasonal changes of the Caspian sea level and annual variations of the sea level with variations of solar activity are studied. The results of the verifications of the sea level forecasts obtained with application of the rules discovered by the authors are given.

  11. Diagenesis in limestone-dolostone successions after 1 million years of rapid sea-level fluctuations: A case study from Grand Cayman, British West Indies

    NASA Astrophysics Data System (ADS)

    Ren, Min; Jones, Brian

    2016-08-01

    Meteoric diagenesis in young marine carbonate sediments has commonly been linked to fluctuations in Quaternary glacio-eustatic sea levels. The extent to which these sea-level changes are recorded in these carbonate successions, however, remains questionable. This is amply demonstrated by the diagenetic record found in the limestones and dolostones of the Cayman Formation (Miocene) on the Cayman Islands. On the eastern part of Grand Cayman, dolomitization that ceased by 1 million years ago created an architecture whereby the limestones in the central part of the island were surrounded by dolostones in coastal areas of the island. Since then, the upper 90 m of the Cayman Formation has been repeatedly cycled through many different marine and meteoric diagenetic zones as large, rapid eustatic oscillations in sea level affected the island. The records of these diagenetic cycles in the dolostones and limestones are, however, different and impossible to match to the cyclic changes in sea level. In the peripheral dolostones, post-dolomitization diagenetic features are sparse. In contrast, the limestones in the interior of the island exhibit a wider variety of meteoric diagenetic features, including extensive dissolution and calcite cementation. The dolostones have low porosity (< 10%) and permeability, whereas the limestones are characterized by high porosity (up to 50%), especially in the lower and middle parts of the studied limestone succession. The different phases of diagenesis found in the limestones, however, cannot be specifically matched to any sea-level fluctuations that have affected these successions. This issue is further exemplified by the fact that that the last marine transgression over the last ~ 16,000 years ago appears to have left no tangible record. The analysis of this succession clearly demonstrates that not all diagenetic regimes will be recorded in the fabrics of limestones or dolostones.

  12. Sudden change: Climate and sea level

    SciTech Connect

    Tanner, W.F.

    1995-10-01

    Dates, magnitudes and rates of Holocene sea-level changes were reviewed at the 1995 meeting of the American Association for the Advancement of Science. Richard B. Alley (Penn. State U.) described laminae in Greenland ice cores, with details at the annual level. A major event of unknown nature occurred at roughly 8,000 B.P. Gerard Bond (Lamont-Doherty Observ., N.Y.) described sediment cores from the North Atlantic, with a major event at 8,000 B.P. Published work of K.S. Petersen (Danish Geol. Survey) from a well near Vust (Denmark) was reviewed: A rapid sea level rise (25 m), then a similar drop centered at 8,000 B.P. at 8-15 cm/yr. W.F. Tanner (Florida State U.) described the beach ridge plain in northern Denmark, where a sequence of more than 270 Holocene ridges shows the date of the big Mid-Holocene sea level change couplet, 8,000 B.P., with a magnitude of {open_quotes}more than 14 m,{close_quotes} plus smaller changes. These data showed vertical magnitudes of the larger sea level events (except the Mid-Holocene catastrophe) in the range of 1-to-5 meters. W.C. Parker (Florida State) sought possible cycles in the same sequence, but they were too poorly defined for detailed forecasts. Charles R. Bentley (U. of Wisconsin) examined the possibility of an early collapse of the West Antarctic marine ice sheet, with a sea level rise of about 5 meters, but concluded that it is unlikely.

  13. Sea Grant Education at the University Level.

    ERIC Educational Resources Information Center

    Fiske, Shirley J.

    1998-01-01

    Sea Grant's investment in university-level education shows a diversity of avenues for supporting students from experience-based internships, merit scholarships, and fellowships to team-based multidisciplinary undergraduate education. Describes such programs as Undergraduate Research Opportunities in ocean engineering, graduate research…

  14. Sea Level Rise National Coastal Property Model

    EPA Science Inventory

    The impact of sea level rise on coastal properties depends critically on the human response to the threat, which in turn depends on several factors, including the immediacy of the risk, the magnitude of property value at risk, options for adapting to the threat and the cost of th...

  15. Late Cretaceous sea level from a paleoshoreline

    SciTech Connect

    McDonough, K.J.; Cross, T.A. )

    1991-04-10

    The contemporary elevation of a Late Cenomanian ({approx}93 Ma) shoreline was determined at five localities along the tectonically stable, eastern margin of the Cretaceous Western Interior Seaway, North America. This shoreline, represented by marine-to-nonmarine facies transitions in strata of the Greenhorn sequence (UZA-2 cycle of Haq et al. (1987)), was identified from outcrop and borehole data. Biostratigraphic zonations constrained the geologic age at each locality. Sequence stratigraphic correlations, based on identifying discrete progradational units and the surfaces that separate them, were used to refine age correlations to better than 100 kyr between localities. A single Cenomanian shoreline was correlated within a single progradational unit, and its elevation was determined at five localities. This paleostrandline occurs 265-286m above present-day sea level, at an average elevation of 276 m. Isostatic and flexural corrections were applied to remove the effects of postdepositional vertical movement, including sediment compaction by loading, uplift due to erosion, and glacial loading and rebound. Errors inherent in each measurement and each correction were estimated. Corrections and their cumulative error estimates yield a Late Cenomanian elevation of 269{plus minus}87 m above present sea level. The corrected elevation approximates sea level at 93 Ma and provides a measure of Late Cenomanian eustasy prior to the Early Turonian highstand. Establishing the absolute value for eustasy at a single point in geologic time provides a frame of reference for calibrating relative sea level curves, as well as constraining the magnitudes of tectonic subsidence, sediment flux, and other variables that controlled water depth and relative sea level.

  16. Benchmarking and testing the "Sea Level Equation

    NASA Astrophysics Data System (ADS)

    Spada, G.; Barletta, V. R.; Klemann, V.; van der Wal, W.; James, T. S.; Simon, K.; Riva, R. E. M.; Martinec, Z.; Gasperini, P.; Lund, B.; Wolf, D.; Vermeersen, L. L. A.; King, M. A.

    2012-04-01

    The study of the process of Glacial Isostatic Adjustment (GIA) and of the consequent sea level variations is gaining an increasingly important role within the geophysical community. Understanding the response of the Earth to the waxing and waning ice sheets is crucial in various contexts, ranging 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 between the ice sheets, the solid Earth, and the oceans. Modern approaches to the SLE are based on various techniques that range from purely analytical formulations to fully numerical methods. Despite various teams independently investigating GIA, we do not have a suitably large set of agreed numerical results through which the methods may be validated. Following the example of the mantle convection community and our recent successful Benchmark for Post Glacial Rebound codes (Spada et al., 2011, doi: 10.1111/j.1365-246X.2011.04952.x), here we present the results of a benchmark study of independently developed codes designed to solve the SLE. This study has taken place within a collaboration facilitated through the European 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 signi?cant 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, which can be often attributed to the different numerical algorithms employed within the community, help to constrain the intrinsic errors in model predictions. These are of fundamental importance for a correct interpretation of the geodetic variations observed today, and

  17. Eustatic and tectonic control of deposition of the lower and middle Pennsylvanian strata of the Central Appalachian Basin

    USGS Publications Warehouse

    Chesnut, D.R.

    1997-01-01

    . Previously, tectonic subsidence of the basin was considered to be the dominant control on deposition of the coal-bearing rocks of the basin. However, new calculations show that eustatic rates are more significant than averaged subsidence rates for the Pennsylvanian Appalachian Basin. Accordingly, sea-level changes are considered to be a dominant control on coastal sedimentation during the Pennsylvanian. However, tectonic subsidence created the accomodation space for preservation of various orders of cyclic sedimentation; the preserved order of cycles was dependent upon the rate of subsidence from basin margin to axis.

  18. A NOAA/NOS Sea Level Advisory

    NASA Astrophysics Data System (ADS)

    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

  19. Ice sheet systems and sea level change.

    NASA Astrophysics Data System (ADS)

    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

  20. Turonian-Santonian depositional and sea level history of the Tarfaya Atlantic coastal basin, SW Morocco

    NASA Astrophysics Data System (ADS)

    Aquit, Mohamed; Kuhnt, Wolfgang; Holbourn, Ann; Hassane Chellai, El; Lees, Jacqueline A.; Kluth, Oliver; Jabour, Haddou; Delaporte, Jean-Pierre

    2013-04-01

    The Turonian to Santonian organic-rich successions deposited in the continuously subsiding Tarfaya Atlantic coastal basin (SW Morocco) allow detailed reconstruction of depositional environments and correlation to eustatic sea level changes. We present high-resolution X-ray fluorescence (XRF) scanning and natural gamma-ray (NGR) records from a newly drilled sedimentary core Tarfaya SN°2 (27° 57´ 43.1´´N, 12° 48´ 37.0´´W), which recovered a continuous sedimentary succession from a middle to outer shelf environment. In the latest Turonian, the late Coniacian, and the middle and latest Santonian, high NGR and Al with low Mn and Ca content indicate pronounced dysoxic horizons that reflect impingement of the oxygen minimum zone on the shelf during sea level highstands. In contrast, lower NGR and Al with higher Mn and Ca values indicate high detrital carbonate content and more oxic conditions related to regressive events in the late Turonian, early to middle Conacian and early Santonian. Exceptionally high sedimentation rates (>10cm/kyr) characterize the late Turonian, and spectral analyses of XRF and NGR data reveal that sedimentation was mostly controlled by obliquity and precession, suggesting an overriding glacioeustatic control. However, the response to orbital forcing weakened during the latest Turonian, when sedimentation rates declined markedly to ~2 cm/kyr. We will extend this study to three newly drilled cores nearby that recovered sediment sequences from the late Albian to late Turonian and from the late Santonian to Campanian in order to retrace the complete Late Cretaceous depositional history of the Tarfaya Basin and to develop a high-resolution carbon isotope stratigraphy allowing correlation to records from other continental margins. Key words: Late Cretaceous, Tarfaya Basin, XRF scanning, natural gamma-ray, oxygen minimum zone, sea level, orbital forcing.

  1. A 3-D coupled ice sheet - sea level model applied to Antarctica through the last 40,000 years

    NASA Astrophysics Data System (ADS)

    Pollard, D.; Gomez, N. A.; Mitrovica, J. X.

    2012-12-01

    A 3-D ice sheet-shelf model is coupled to a gravitationally self-consistent global sea-level model valid for a self-gravitating, viscoelastically deforming Earth, and applied to Antarctica through the last 40,000 years. The sea-level model simulates far-field and near-field departures in ocean depths from a simple eustatic (i.e., globally uniform) curve. The coupled model captures interactions due to the gravitational effect of varying ice mass on the proximal ocean and grounding-line depths, which is a negative feedback tending to slow down marine grounding-line retreat especially in West Antarctica. The parameterized ice-sheet forcing includes sub-ice-shelf oceanic melting based on the cavity-box model of Olbers and Hellmer (Ocean Dynamics, 2010), driven by circum-Antarctic ocean temperatures over the last 22,000 yr from the A-OGCM results of Liu et al. (Science, 2009). Northern Hemispheric ice variations required as input to the sea-level model are adopted from the ICE-5G ice sheet history (Peltier, Ann. Rev. Earth Plan. Sci., 2004). The coupled model output includes 3-D ice distributions and global maps of bedrock elevation and sea level, from 40,000 yr BP to the present. Presented results will focus on total ice volume through time, ice distributions and sea levels at the Last Glacial Maximum and present, grounding-line retreat patterns though the last deglaciation, and relative sea level curves at selected locations. Sensitivities to coupled vs. uncoupled versions, model resolution, and several other key parameters will be assessed.

  2. Geochronology and subsurface stratigraphy of Pukapuka and Rakahanga atolls, Cook Islands: Late Quaternary reef growth and sea level history

    USGS Publications Warehouse

    Gray, S.C.; Hein, J.R.; Hausmann, R.; Radtke, U.

    1992-01-01

    Eustatic sea-level cycles superposed on thermal subsidence of an atoll produce layers of high sea-level reefs separated by erosional unconformities. Coral samples from these reefs from cores drilled to 50 m beneath the lagoons of Pukapuka and Rakahanga atolls, northern Cook Islands give electron spin resonance (ESR) and U-series ages ranging from the Holocene to 600,000 yr B.P. Subgroups of these ages and the stratigraphic position of their bounding unconformities define at least 5 periods of reef growth and high sea-level (0-9000 yr B.P., 125,000-180,000 yr B.P., 180,000-230,000 yr B.P., 300,000-460,000 yr B.P., 460,000-650,000 yr B.P.). Only two ages fall within error of the last interglacial high sea-level stand (???125,000-135,000 yr B.P.). This paucity of ages may result from extensive erosion of the last intergracial reef. In addition, post-depositional isotope exchange may have altered the time ages of three coral samples to apparent ages that fall within glacial stage 6. For the record to be preserved, vertical accretion during rising sea-level must compensate for surface lowering from erosion during sea-level lowstands and subsidence of the atoll; erosion rates (6-63 cm/1000 yr) can therefore be calculated from reef accretion rates (100-400 cm/1000 yr), subsidence rates (2-6 cm/1000 yr), and the duration of island submergence (8-15% of the last 600,000 yr). The stratigraphy of coral ages indicates island subsidence rates of 4.5 ?? 2.8 cm/1000 yr for both islands. A model of reef growth and erosion based on the stratigraphy of the Cook Islands atolls suggests average subsidence and erosion rates of between 3-6 and 15-20 cm/1000 yr, respectively. ?? 1992.

  3. Eustatic control on epicontinental basins: The example of the Stuttgart Formation in the Central European Basin (Middle Keuper, Late Triassic)

    NASA Astrophysics Data System (ADS)

    Franz, M.; Nowak, K.; Berner, U.; Heunisch, C.; Bandel, K.; Röhling, H.-G.; Wolfgramm, M.

    2014-11-01

    The deposition of the Stuttgart Formation ('Schilfsandstein'), commonly considered as a type-example of the Carnian Pluvial Event, was controlled by high frequent 4th order sequences that resulted in pre-, intra- and post-Schilfsandstein transgressions from Tethyan waters into the epicontinental Central European Basin (CEB). The pre-Schilfsandstein transgression flooded the CEB trough gates to the Southeast and resulted in a wide-spread inland sea that was characterised by increased biological productivity, predominantly oxic conditions and enabled the immigration of euryhaline marine fauna with plankton, ostracodes, fishes, bivalves and the gastropods Omphaloptychia suebica n. sp. and Settsassia stuttgartica n. sp. The rather short-term intra- and post-Schilfsandstein transgressions flooded the CEB from the Southwest and Southeast and established a shallow brackish inland sea that stretched up to North Germany. Both, the 4th and 3rd order sequences derived from the succession in the CEB correlate well with those derived from successions of Tethyan shelfs. Therefore pronounced circum-Tethyan eustatic cycles are evidenced and may have had considerable impact on prominent middle Carnian events: Reingraben turnover, Carnian Pluvial Event, Carnian Crisis and Mid Carnian Wet Intermezzo. The broad circum-Tethyan evidence of 106-year scale cycles suggests glacioeustatic sea-level changes even in the Triassic Greenhouse period.

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

    NASA Astrophysics Data System (ADS)

    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

  5. Sea level changes in the Holocene

    SciTech Connect

    Tanner, W.F. )

    1993-03-01

    Beach ridge data provide much information on the history of sea level changes through all of Holocene time. Two data sets start at about 12,000 B.P., one of them essentially continuous to now with data every 40--50 yrs. Another starting at 7,600 B.P. is continuous to the present. Others span the last 3,200 years. These records agree reasonably closely, and show the Little Ice Age (since 1,200 A.D.). The sea level changes in these data include the following: (a) Early Holocene crisis, about 8,000 B.P. The Swedish (Baltic Sea) record ends about this time, the Hudson Bay record starts at roughly this time, and the Danish record has a 300--500-year gap at about this time. From the latter, it appears that sea level rose sharply, shortly before 8,000 B.P., and fell again shortly after 8,000 B.P. These were the largest changes in Holocene time. The vertical change may have been as much as 12--18 meters, and the rate of change as much as 5--8 cm/yr, perhaps the maximum possible. In stable areas, evidence for these changes are now 25--30 meters below sea level. (b) Early Holocene general rise, up to about 8,000 B.P. Evidence for this is now known only on uplifted coasts. (c) Middle Holocene high, 2 m above present MSL 7,000--5,500 B.P. (d) Middle Holocene low, 3--4 m below present MSL 5,000--3,500 B.P. (e) Several changes up to 2 meters, especially since 3,000 B.P. In general, rates of change have been close to 1 cm/yr (major exceptions noted above). The only persistent interval was that between beach ridges; each ridge and its associated swale seem to have been built by a sea-level rise-and-fall couplet, having dimensions so small (perhaps 5--30 cm) that they could be overlooked easily on tide-gauge records. The average apparent time interval was 35--50 years.

  6. Coastal subsidence and relative sea level rise

    USGS Publications Warehouse

    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).

  7. Sea-level changes before large earthquakes

    USGS Publications Warehouse

    Wyss, M.

    1978-01-01

    Changes in sea level have long been used as a measure of local uplift and subsidence associated with large earthquakes. For instance, in 1835, the British naturalist Charles Darwin observed that sea level dropped by 2.7 meters during the large earthquake in Concepcion, CHile. From this piece of evidence and the terraces along the beach that he saw, Darwin concluded that the Andes had grown to their present height through earthquakes. Much more recently, George Plafker and James C. Savage of the U.S Geological Survey have shown, from barnacle lines, that the great 1960 Chile and the 1964 Alaska earthquakes caused several meters of vertical displacement of the shoreline. 

  8. Hurricanes, sea level rise, and coastal change

    USGS Publications Warehouse

    Sallenger,, Asbury H.; Wang, Ping; Rosati, Julie D.; Roberts, Tiffany M.

    2011-01-01

    Sixteen hurricanes have made landfall along the U.S. east and Gulf coasts over the past decade. For most of these storms, the USGS with our partners in NASA and the U.S. Army Corps of Engineers have flown before and after lidar missions to detect changes in beaches and dunes. The most dramatic changes occurred when the coasts were completely submerged in an inundation regime. Where this occurred locally, a new breach was cut, like during Hurricane Isabel in North Carolina. Where surge inundated an entire island, the sand was stripped off leaving marshy outcrops behind, like during Hurricane Katrina in Louisiana. Sea level rise together with sand starvation and repeated hurricane impacts could increase the probabilities of inundation and degrade coasts more than sea level rise alone.

  9. Rising Sea Levels: Truth or Scare?

    ERIC Educational Resources Information Center

    Peacock, Alan

    2007-01-01

    When "ITV News" ran an item that shocked the author, about rising sea levels that will have caused the entire evacuation of the islands by the end of this year, he began to wonder whether the Pacific Ocean is really rising as fast as this. The media reporting of such things can be a double-edged sword. On the one hand, it brought to the author's…

  10. Influence of relative sea level on a marginal sea environment and its implication for reconstructing ice volume changes using IODP Expedition 346, Site U1427

    NASA Astrophysics Data System (ADS)

    Sagawa, T.; Tada, R.; Murray, R. W.; Alvarez Zarikian, C. A.

    2014-12-01

    Pleistocene climate is characterized by glacial-interglacial changes in the ice volume. Reconstruction of ice volume is essential for understanding past climate change and is usually based on variations in the oxygen isotope composition of benthic foraminifera shells, which in turn are influenced by bottom water temperature. Another approach is to use the oxygen isotope composition of planktonic foraminifer in semi-enclosed seas, where the surface environments are sensitive to sea level change. The oceanographic condition at the sea north of Japanese islands is also largely influenced by the eustatic change. The Japanese islands and inter island shallow straits (sill depth less than 130 m) limit seawater exchange between the North Pacific and the marginal seas. The oxygen isotope record in this area show a unique feature and is a candidate for reconstructing global sea level history. During the Integrated Ocean Drilling Program (IODP) Expedition 346 "Asian Monsoon" (29 July-27 September 2013), a shallow marine sediment sequence was recovered from the slope of north coast of western Japan, Site U1427. The shipboard data highlight the sediment contains well-preserved foraminifer and has high sedimentation rate of ~40 cm/kyr. A complete splice down to ~400 m provides the potential for a continuous record for the last ~1.4 Ma. Preliminary isotope results show isotopic variations correspond to lithological change and therefore show similar variation to physical properties of the sediment, such as bulk density, natural gamma ray, and so on. The result suggests that the oxygen isotope of foraminifer in this area may provide key information on past global ice volume changes.

  11. Synsedimentary tectonics, mud-mounds and sea-level changes on a Palaeozoic carbonate platform margin: a Devonian Montagne Noire example (France)

    NASA Astrophysics Data System (ADS)

    Bourrouilh, Robert; Bourque, Pierre-André; Dansereau, Pauline; Bourrouilh-Le Jan, Françoise; Weyant, Pierre

    1998-06-01

    The Devonian sedimentary succession of the southern flank of the Montagne Noire (France) was deposited along a divergent margin. This paper is a contribution to describe and evaluate biogenic, sedimentary, geochemical and micropalaeontological features as indicators of sea-level changes and global history of the Devonian in this area. Following transgression and shallow-water environments during Early Devonian time (Lochkovian to early Emsian), biogenic mud-rich mounds with stromatactis developed during latest Emsian at the platform margin. The depth of the Devonian sea was increasing and the seafloor passed below the photic zone and the lower limit of storm wave base during the Emsian. Growth and seismic faults affected the mounds and created Neptunian cracks and crevices, quickly filled with sedimentary material (pisoids) and cements (Neptunian dykes and veins). Light and CL-microscopy, and stable isotope geochemistry show that stromatactis, cements of Neptunian dykes, veins and pisoid cortices are early marine, whereas the red finely crystalline material that forms the bulk of the mound has been cemented in the near-surface diagenetic environment, after the early marine cementation of stromatactis and Neptunian dykes and veins, by meteoric or hydrothermal fluids. The sedimentary rocks overlying the stromatactis mounds exhibit regularly condensed iron and manganese-rich layers, interrupted by the Kellwasser hypoxic horizon. These condensed deposits developed up to the Famennian in a context of carbonate gravity sedimentation and became more and more rhythmic and frequent up section. The occurrence and irregular distribution of large-scale submarine mass flows during Frasnian and Famennian times can be related to block faulting on which Lower Devonian stromatactis mounds could have been uplifted by this block faulting to form seamounts. The sea-level fluctuations detected in the southern flank of Montagne Noire are compared to the Devonian eustatic sea-level curve

  12. Probabilistic assessment of sea level during the last interglacial stage.

    PubMed

    Kopp, Robert E; Simons, Frederik J; Mitrovica, Jerry X; Maloof, Adam C; Oppenheimer, Michael

    2009-12-17

    With polar temperatures approximately 3-5 degrees C warmer than today, the last interglacial stage (approximately 125 kyr ago) serves as a partial analogue for 1-2 degrees C global warming scenarios. Geological records from several sites indicate that local sea levels during the last interglacial were higher than today, but because local sea levels differ from global sea level, accurately reconstructing past global sea level requires an integrated analysis of globally distributed data sets. Here we present an extensive compilation of local sea level indicators and a statistical approach for estimating global sea level, local sea levels, ice sheet volumes and their associated uncertainties. We find a 95% probability that global sea level peaked at least 6.6 m higher than today during the last interglacial; it is likely (67% probability) to have exceeded 8.0 m but is unlikely (33% probability) to have exceeded 9.4 m. When global sea level was close to its current level (>or=-10 m), the millennial average rate of global sea level rise is very likely to have exceeded 5.6 m kyr(-1) but is unlikely to have exceeded 9.2 m kyr(-1). Our analysis extends previous last interglacial sea level studies by integrating literature observations within a probabilistic framework that accounts for the physics of sea level change. The results highlight the long-term vulnerability of ice sheets to even relatively low levels of sustained global warming.

  13. Late Pliocene and early Pleistocene sea-level timing and amplitudes derived from fossil ostracod assemblages: Canterbury Basin, New Zealand

    NASA Astrophysics Data System (ADS)

    Nakamura, M.; Kusunoki, S.; Yamada, K.; Hoyanagi, K.

    2013-12-01

    IODP Expedition 317 cruise drilled cores at three shelf sites (U1353, U1354 and U1351) and one slope site (U1352), in water depths between 85 and 344 m, to understand relationships between sea-level change and sequence stratigraphy. The shelf sites are well suited to reconstruction of high-resolution sea-level fluctuations because of high sedimentation rates from the uplifting Southern Alps. We examined fossil ostracod assemblages from the shelf sites to reconstruct paleo-water depth fluctuations and their amplitudes. We identified 178 ostracod species and 70 genera from more than 160 samples. Q-mode factor analysis was performed on ostracod taxa with abundances of >3.5 % in each sample containing >50 specimens. Six varimax factors were explained 70.8% of the total variance. Paleo-water depths in each factor were calibrated with reference to recent ostracodes occurring around the sites as follows: first factor, middle shelf (50-80 m); second factor, middle to outer shelf (60-130 m); third factor, middle to outer shelf (55-115 m); fourth factor, lagoon, estuary and inner shelf (0-50 m); fifth factor, middle to outer shelf (80-200 m); sixth factor, outer shelf (130-200 m). Factor analysis of ostracod assemblages reveal at least, eight transgressive- and regressive-cycles at Site U1353, seventeen at Site U1354 and two at Site U1351. These cycles probably correspond to a subset of MIS stages between MIS M2 and MIS 40. Furthermore, amplitudes of these paleo-water-depth cycles are expected to equate to eustatic amplitudes because shelf sedimentation has been continuous and minimal subsidence can have occurred during the short time period involved. We therefore estimate that eustatic amplitudes were: 10 - 30 m from 3.1 to 2.8 Ma, ca. 100 m from 2.8 to 2.6 Ma, and 30 - 115 m from 1.8 to1.2 Ma. These amplitudes, together with the timing of the increase in amplitudes (~2.7 Ma), agree with estimates derived from oxygen isotopic records (Raymo et al., 2005), suggesting that

  14. The Cenomanian/Turonian carbon burial event, Bass River, NJ, USA: Geochemical, paleoecological, and sea-level changes

    USGS Publications Warehouse

    Sugarman, P.J.; Miller, K.G.; Olsson, R.K.; Browning, J.V.; Wright, J.D.; De Romero, L. M.; White, T.S.; Muller, F.L.; Uptegrove, J.

    1999-01-01

    The Bass River borehole (ODP Leg 174AX) recovered approximately 200 ft (61 m) of upper Cenomanian to lower Turonian strata from the New Jersey Coastal Plain, USA, including the expression of a global carbon burial event. The Cenomanian/Turonian (C/T) boundary is recognized at Bass River at ???1935.5 ft (589.9 m) based on the contact of nannofossil Microstaurus chiastius and Eiffellithus eximius Subzones of the Parhabdolithus asper Zone. Carbon isotopic records of both Gavelinella and Epistomina show a large (>2???) increase immediately below the C/T boundary, with maximum values of 6??? in Epistomina and 4.3??? in Gavelinella. The ??13C offset between these taxa is constant and we conclude that Epistomina, like Gavelinella, faithfully records seawater ??13C changes. Above the sharp ??13C increase, elevated ??13C and sedimentary organic carbon (>0.9%) values continue into the lower Turonian, culminating in a sharp ??13C decrease. High ??13C values in the uppermost Cenomanian-lower Turonian at Bass River correlate with a global carbon burial event recorded in Europe and the U.S. Western Interior; we estimate the duration of this event at Bass River as 400-500 k.y. Although the carbon burial event occurred during a long-term eustatic rise (10 m.y. scale), it occurs within a 1-2 m.y. long sequence at Bass River that indicates no relationship with sea-level lowering on the m.y. scale. The carbon burial event does not appear to be associated with maximum flooding either, indicating little correlation with sea-level rise on a m.y. scale. Within the sequence spanning the carbon event, there are at least 4 shallowing-upward parasequences (durations ???350-460 k.y.) indicated by changes in abundance and type of Epistomina species, ??18O variations, and minor lithologic variations. The highest occurrences of 6 Epistomina species and the origination of Epistomina sliteri Olsson n. sp. are associated with the parasequences and possibly with higher ??18O values. There is no

  15. Global increasing of mean sea level and erroneous treatment of a role of thermal factors

    NASA Astrophysics Data System (ADS)

    Barkin, Yu. V.

    2009-04-01

    Satellite methods of studies of the ocean surface - methods of altimetry - have been obtained intensive development in the last decades (since 1993). However, altimetry studies with the help of special satellites such as TOPEX-Poseidon not only have not cleared up understanding of the phenomenon of increase of sea level (SLR), but have even more confused and without that a complex question on the reasons of increase of sea level. Appeared, that classical determinations of average velocity of increase of sea level on coastal observations (1.4-1.7 mm / yr) approximately for 0.8-1.0 mm / yr it is less, rather than by modern satellite determinations of satellites TOPEX - Poseidon etc. (2.5 - 2.8 mm / yr). On the basis of the data of altimetry observations of TOPEX-Poseidon and Jason for the period 1993-2003 for geocentric velocity of increase of sea level (of global ocean) the value 2.8+/-0.4 mm / yr [1] has been obtained. In the given report the full answer is actually is given to a question put by leading experts on research of the sea level: "The TOPEX/Poseidon and Jason satellite altimeter missions provided a 12 year record of sea level change, which show increase of global mean sea level of 2.8+/-0.4 mm/yr, with considerable geographic variation. An important question for climate studies is to determine the cause of this change - specifically how much of the change is due to steric (heating) versus eustatic (runoff, melting ice, etc.) contribution?" [1]. There is, a big value of average velocity of increase of the sea level on the satellite data, it is possible to explain only by kinematical effect in data of observations. The motion of the satellite "is concerned" to the centre of mass of our planet, and its position is determined by a geocentric radius - vector. Therefore northern drift of the centre of mass in the Earth body [2] as though results in reduction of distances from the satellite up to the sea surface in the southern hemisphere and to their reduction

  16. Assessment of the sensitivity of the southern coast of the Gulf of Corinth (Peloponnese, Greece) to sea-level rise

    NASA Astrophysics Data System (ADS)

    Karymbalis, Efthimios; Chalkias, Christos; Chalkias, George; Grigoropoulou, Eleni; Manthos, George; Ferentinou, Maria

    2012-12-01

    The eustatic sea-level rise due to global warming is predicted to reach approximately 18-59 cm by the year 2100, which necessitates the identification and protection of sensitive sections of coastline. In this study, the classification of the southern coast of the Gulf of Corinth according to the sensitivity to the anticipated future sealevel rise is attempted by applying the Coastal Sensitivity Index (CSI), with variable ranges specifically modified for the coastal environment of Greece, utilizing GIS technology. The studied coastline has a length of 148 km and is oriented along the WNW-ESE direction. CSI calculation involves the relation of the following physical variables, associated with the sensitivity to long-term sea-level rise, in a quantifiable manner: geomorphology, coastal slope, relative sea-level rise rate, shoreline erosion or accretion rate, mean tidal range and mean wave height. For each variable, a relative risk value is assigned according to the potential magnitude of its contribution to physical changes on the coast as the sea-level rises. Every section of the coastline is assigned a risk ranking based on each variable, and the CSI is calculated as the square root of the product of the ranked variables divided by the total number of variables. Subsequently, a CSI map is produced for the studied coastline. This map showed that an extensive length of the coast (57.0 km, corresponding to 38.7% of the entire coastline) is characterized as highly and very highly sensitive primarily due to the low topography, the presence of erosionsusceptible geological formations and landforms and fast relative sea-level rise rates. Areas of high and very high CSI values host socio-economically important land uses and activities.

  17. Birth of the modern Chesapeake Bay estuary between 7.4 and 8.2 ka and implications for global sea-level rise

    NASA Astrophysics Data System (ADS)

    Bratton, John F.; Colman, Steven M.; Thieler, E. Robert; Seal, Robert R.

    2002-12-01

    Two major pulses of sea-level rise are thought to have taken place since the last glacial maximum — meltwater pulses (mwp) 1A (12 cal ka) and 1B (9.5 cal ka). Between mwp 1B and about 6 cal ka, many of the complex coastal ecosystems which ring the world's oceans began to form. Here we report data for rhenium, carbon isotopes, total organic carbon, and fossil oysters from Chesapeake Bay which span the transition from fresh to brackish water conditions in the bay in the mid-Holocene. These data constrain sea-level change and resulting environmental change in the bay. They indicate that the transition was rapid, and that it was produced by (1) a third pulse of rapid eustatic sea-level rise, or (2) a geometry of the prehistoric Chesapeake Bay basin which predisposed it to a nonlinear response to a steadily rising sea level. Similar nonlinear changes in vulnerable coastal environments are likely to take place in the future due to polar warming, regardless of the timing or rate of sea-level rise.

  18. MIS 5e sea level: up to what point can we use literature reviews to answer the most pressing questions on the Last Interglacial ice sheets?

    NASA Astrophysics Data System (ADS)

    Rovere, A.; Raymo, M. E.

    2014-12-01

    During MIS 5e (between ~128 and 116 kyr BP) greenhouse gas concentrations were comparable to pre-industrial levels, summer insolation was higher by ~10% at high latitudes and polar temperatures in both hemispheres were about 3-5 °C warmer than today. Sea level (SL) at this time has been a subject of numerous studies (and some debate) with ~1000 sites with MIS 5e sea level markers recognized worldwide. Recently, Kopp et al. (Nature, 2009) and Dutton & Lambeck (Science, 2012) analyzed worldwide datasets of sea level markers pertaining to the last interglacial. After accounting for GIA, they reached similar conclusions that eustatic (i.e., globally averaged) sea level (ESL) was between +5 and +9.4 m above modern during MIS 5e. Furthermore, Kopp et al. (Nature, 2009; GJI, 2013) suggest that sea level was not uniform during the LIG, but instead underwent at least two rapid oscillations including a rapid late 5e rise first proposed by Hearty et al. (QSR, 2007) and later by O'Leary et al. (Nat. Geo., 2013). Investigating the temporal and geographic variability of MIS 5e sea level opens new lines of research, in particular the possibility to fingerprint (Hay et al., QSR, 2014) the source of the proposed rapid ice sheet collapse near the end of the Last Interglacial. In this presentation we ask: can we use a database of published sea level estimates for this purpose? To answer this question, we built a relative sea level (RSL) database using RSLcalc 2.0; this is a relational database specifically designed to review relative sea level data points while keeping all the relevant information contained in the original publications. RSlcalc allows to estimate the measurement error (on the actual elevation of the SL feature), the error on the indicative range (the elevation range occupied by a sea level indicator) as well as the reference water level (the relationship between the marker and the former sea level). We show that the majority of published data have an accuracy of few

  19. The influence of sea-level changes on tropical coastal lowlands; the Pleistocene Coropina Formation, Suriname

    NASA Astrophysics Data System (ADS)

    Wong, Th. E.; de Kramer, R.; de Boer, P. L.; Langereis, C.; Sew-A-Tjon, J.

    2009-04-01

    The Pleistocene Coropina Formation largely constitutes the Old Coastal Plain of Suriname. It is exposed fully only in open-pit bauxite mines in the central coastal plain as part of the unconsolidated overburden of Paleocene-Eocene bauxites. This study deals with the stratigraphy, sedimentology and chronology of this formation, and is based on a study in the recently closed Lelydorp-III bauxite mine operated by N.V. BHP Billiton Maatschappij Suriname. The Coropina Formation consists of the Para and Lelydorp Members. We present a detailed lithological subdivision of these members. In the Para Member, four units are discerned which are grouped in two transgressive cycles, both ranging upward from terrestrial towards chenier and coastal mudflat deposits reflecting glacio-eustatic sea-level changes. The sandy sediments represent fluviatile and beach-bar (chenier) deposits, and were supplied by rivers from the Precambrian basement and to a lesser extent by westward longshore coastal drift. Clays, largely derived from the Amazon River and transported alongshore over the shelf, were deposited in extensive coastal mudflats. The Lelydorp Member, also comprising four units, represents a depositional system that is closely comparable to the recent Suriname coastal setting, i.e., a lateral and vertical alternation of mudflat and chenier deposits formed over a period characterised by more or less constant sea level. Palaeomagnetic data indicate a dominantly reversed magnetic polarity in the Para Member, whereas the Lelydorp Member shows a normal magnetic polarity with a minor reversed polarity overprint. The reversed polarities of the Para Member exclude a Brunhes Chron (0.78-0.0 Ma) age, and thus assign it to the Matuyama Chron (2.58-0.78 Ma). This implies that the Coropina Formation is much older than hitherto assumed, and that one or more (long-term) hiatuses are not recognizable in the lithological succession.

  20. Holocene sea-level changes in King George Island, West Antarctica, by virtue of geomorphological coastal evidences and diatom assemblages of sediment sections.

    NASA Astrophysics Data System (ADS)

    Poleshchuk, Ksenia; Verkulich, Sergey; Pushina, Zina; Jozhikov, Ilya

    2015-04-01

    A new curve of relative sea-level change is presented for the Fildes peninsula, King George Island, West Antarctic. This work is based on renewed paleogeography data, including coastal geomorphological evidence, diatom assemblages of lakes bottom sediments and radiocarbon datings of organics. The new data were obtained in several sections of quaternary sediments and groups of terraces, and allows us to expand and improve relevant conception about relative sea level changes in the King George Island region. The new radiocarbon datings of organics (mosses and shells) allows reconstructing Holocene conditions that maintain and cause the sea-level changes. Sea diatom assemblages of Dlinnoye lake bottom sediment core (that complies period about 8000 years B.P.) mark altitude of marine water penetrated into the lake. The altitudes of shell remains, which have certain life habits and expect specific salinity and depth conditions, coupled with their absolute datings, indicate the probable elevation of the past sea level. The Mid-Holocene marine transgression reached its maximum level of 18-20 m by 5760 years B.P. The transgression influenced the deglaciation of the Fildes peninsula and environment conditions integrally. The ratio of glacio-isostatic adjustment velocity and Holocene transgression leaded to the decrease of relative sea level during the Late Holocene excluding the short period of rising between 2000 and 1300 years B.P. Comparing this data with the curve for Bunger oasis, East Antarctica, introduced earlier gives an interesting result. Despite the maximum altitudes of relative sea-level rise in King George region were higher and occurred later than in Bunger oasis region, the short-term period of Late Holocene sea-level rising contemporizes. Besides that, this work allow to realize a correlation between regions of Antarctica and adjacent territory. That, in turn, lets answer the question of tectonic and eustatic factors ratio and their contribution to the

  1. Regional, holocene records of the human dimension of global change: sea-level and land-use change in prehistoric Mexico

    NASA Astrophysics Data System (ADS)

    Sluyter, Andrew

    1997-02-01

    Regional, Holocene records hold particular relevance for understanding the reciprocal nature of global environmental change and one of its major human dimensions: "sustainable agriculture", i.e., food production strategies which entail fewer causes of and are less susceptible to environmental change. In an epoch of accelerating anthropogenic transformation, those records reveal the protracted regional causes and consequences of change (often agricultural) in the global system as well as informing models of prehistoric, intensive agriculture which, because of long tenures and high productivities, suggest strategies for sustainable agricultural in the present. This study employs physiographic analysis and the palynological, geochemical record from cores of basin fill to understand the reciprocal relation between environmental and land-use change in the Gulf of Mexico tropical lowland, focusing on a coastal basin sensitive to sea-level change and containing vestiges of prehistoric settlement and wetland agriculture. Fossil pollen reveals that the debut of maize cultivation in the Laguna Catarina watershed dates to ca. 4100 BC, predating the earliest evidence for that cultivar anywhere else in the lowlands of Middle America. Such an early date for a cultivar so central to Neotropical agroecology and environmental change, suggests the urgency of further research in the study region. Moreover, the longest period of continuous agriculture in the basin lasted nearly three millennia (ca. 2400 BC-AD 550) despite eustatic sea-level rise. Geochemical fluxes reveal the reciprocity between land-use and environmental change: slope destabilization, basin aggradation, and eutrophication. The consequent theoretical implications pertain to both applied and basic research. Redeploying ancient agroecologies in dynamic environments necessitates reconstructing the changing operational contexts of putative high productivity and sustainability. Adjusting land use in the face of global

  2. Differences between mean tide level and mean sea level

    NASA Astrophysics Data System (ADS)

    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.

  3. Updating Maryland's sea-level rise projections

    USGS Publications Warehouse

    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.

  4. Intraplate stresses and continental margin stratigraphy: New constraints on the relative contributions of tectonics and eustasy to the record of sea level changes

    SciTech Connect

    Cloetingh, S.; Kool, H. )

    1990-05-01

    Recent advances in modeling the tectonics of intraplate regions have established a causal relation between changes in plate-tectonic regimes and short-term changes in the orientation and magnitude of stress fields in the lithosphere. These temporal changes in stress produce vertical motions of the crust with a rate and magnitude consistent with magnitudes inferred from records of (apparent) sea level changes. Stress-induced vertical motions of the lithosphere could provide a tectonic explanation of short-term changes in sea level, such as the second-order and third-order Exxon cycles. The sea level record can be used as an independent source of information for the analysis of paleostress fields in the plates. Geodynamic modeling studies were conducted, therefore, to discriminate the relative contributions of tectonics and glacio-eustasy to the apparent sea level record and to discriminate global vs. regional tectonic components in the sea level record. Modeling strongly suggests that even in a passive margin tectonic setting, the effects of tectonics generally overwhelm eustatic contributions to the sea level record. The studies also show a close correlation between changes in intraplate-tectonic regimes in the North Atlantic caused in plate kinematics and plate interactions and the timing of changes in sea level shown in global Exxon charts. These results suggest that the charts, which are based primarily on data from the northern/central Atlantic and the North Sea reflect to a large extent the plate-tectonic evolution of this area. Apart from emphasizing the need to develop further rigorous stratigraphic criteria to separate of tectonics and eustasy on an intrabasinal scale, the studies emphasize the need to test the Vail concept in areas outside the North Atlantic. For this purpose, stratigraphic modeling for continental margins of other ocean basins based on recent ODP (Ocean Drilling Program).

  5. Holocene Sea-Level Rise in New Jersey and W. North Atlantic Reefs: Untangling Natural and Anthropogenic Effects

    NASA Astrophysics Data System (ADS)

    Stanley, A. M.; Miller, K. G.; Sugarman, P. J.; Browning, J. V.

    2004-12-01

    The history of pre-anthropogenic Holocene global sea level has not been well constrained. We provide Holocene sea-level estimates for five new boreholes on the New Jersey (NJ) coast (Rainbow Island, Great Bay I, Great Bay II, Cape May, and Island Beach). We analyzed facies, radiocarbon dated marsh deposits, and derived a sea-level record by compiling new and previously published NJ data. Our sea-level record shows a constant rise of ˜2 mm/yr from ˜7000 yrBP to present. This contrasts sharply with previous NJ estimates that suggested a slowing in rise since 2000 yrBP. Comparison with other NJ locations suggests surprising uniformity in the rate of rise amongst sites as far flung as Cape May and Cheesequake (200 km apart), suggesting a far-field response to the Laurentide ice sheet. The "Barbados/western North Atlantic reefs sea-level" record shows a major decrease in the rate of rise from 12 mm/yr to ˜2 mm/yr between 7000 and 8000 yrBP. Data from NJ and western North Atlantic reefs indicate a constant rate of rise of ˜2 mm/yr since ˜7000 yrBP. This suggests a background, pre-anthropogenic sea-level rise of 2 mm/yr for the entire east coast of the U.S. This background includes both the global (water volume) rise and far-field geoidal subsidence due to removal of the Laurentide ice sheet and water loading (estimated as 1 mm/yr in the modern). Applying the modern subsidence rate to the Holocene suggests a eustatic rise of ˜1 mm/yr since 7000 yrBP. Based on tide gauge data, regional sea-level rise averaged 3 mm/yr from 1900-1995, with higher rates (4 mm/yr) locally due to compaction and groundwater withdrawal. We conclude that the anthropogenically induced rise in sea level was ˜1 mm/yr from 1900-1995.

  6. On how climate variability influences regional sea level change

    NASA Astrophysics Data System (ADS)

    Brunnabend, Sandra-Esther; Kusche, Jürgen; Rietbroek, Roelof; Forootan, Ehsan

    2016-04-01

    Regional trends in sea level change are strongly influenced by climate variations, such as ENSO (El-Nino Southern Oscillation), the IOD (Indian Ocean Dipole), or the PDO (Pacific Decadal Oscillation). Hence, before computing long term regional sea level change, these sea level variations need to be taken into account as they lead to strong dependencies of computed regional sea level trends on the time period of the investigation. In this study, sea level change during the years 1993 to 2013 is analysed to identify the dominant modes of sea level change caused by climate variations. Here, two different gridded altimetry products are analysed, namely ESA's combined CCI SeaLevel v1.1 ECV product (doi: 10.5270/esa-sea_level_cci-1993_2013-v_1.1-201412), and absolute dynamic topography produced by Ssalto/Duacs and distributed by Aviso, with support from Cnes (http://www.aviso.altimetry.fr/duacs/). Reconstructions using the different decomposition techniques including the standard principle component analysis (PCA), rotated empirical orthogonal functions (REOF) and independent component analysis (ICA) method are analysed. They are compared with sea level change modelled with the global finite-element sea-ice ocean model (FESOM). The results indicate that from the applied methods, ICA is most suitable to separate the individual climate variability signals in independent modes of sea level change. This especially holds for extracting the ENSO contribution in sea level changes, which was better separated by applying ICA, from both altimetry and modelled sea level products. In addition, it is presented how modelled sea level change reflects climate variations compared to that identified in the altimetry products.

  7. Late Glacial to Holocene evolution and sea-level history of Gulf of Gemlik, Sea of Marmara, Turkey

    NASA Astrophysics Data System (ADS)

    Sabuncu, Asen; Kadir Eriş, K.; Kaslilar, Ayse; Namık Çaǧatay, M.; Gasperini, Luca; Filikçi, Betül

    2016-04-01

    The Gulf of Gemlik is an E-W elongated trans-tensional basin with a maximum depth of 113 m, located on the middle strand of the North Anatolian Fault (NAF) in the south eastern part of the Sea of Marmara (SoM). While during the Holocene the sea level in the Gulf of Gemlik changed in tandem with the water level changes in the SoM, it may have been different in the late glacial when the Sea of Marmara was lacustrine. Beside the tectonic activity related to the NAFZ, eustatic sea level changes would have controlled the basin evolution and consequent sedimentary history during the different paleocanographic phases of the SoM. Considering the limited studies on the late glacial-Holocene stratigraph of the Gulf of Gemlik, this study aims to investigate the depositional units and their environments with respect to different allogenic and autogenic controls. For these purposes, we analyzed over 300 2 - 7 kHz bandwidth high-resolution gridded seismic sub-bottom CHIRP profiles together with 70 kHz high resolution multibeam bathymetry with backscatter data. Four seismic stratigraphic units were defined and correlated with chronstratigraphic units in five piston cores covering the last 15.8 ka BP according to radiocarbon ages (14C). The depth-scale accuracy of chronostratigraphic units in cores is of key importance for the precise calculation of sedimentation rates. Correlation between the seismic profiles and cores were made by matching Multi-Sensor Core-Logger (MSCL) data and seismic reflection coefficients and amplitudes for different stratigraphic units. The impedance data derived from the logger were used to generate a synthetic seismogram. We used an approach to display, estimate, and correct the depth-scale discrepancies due to oversampling affecting the upper part of sedimentary series during piston coring. The method is based on the resynchronization of synthetic seismograms computed from high-quality physical property logs to the corresponding CHIRP profiles. Each

  8. Eustatic and tectonic effects in sequences stratigraphy of the paralic-shelfal marine section, upper cretaceous, Alabama

    SciTech Connect

    King, D.T. Jr. )

    1993-09-01

    In Alabama, sequence stratigraphic facies relations within the late Santonian to latest Maastrichtian (85-67 Ma) marine section have been strongly influenced by second-, third-, and fourth-order sea level changes related both to global eustasy and regional tectonics. Through detailed lithostratigraphic and biochronostratigraphic correlations, one can delineate the dictating mechanism (eustasy versus tectonics). In the outcrop region, the marine section is 450 m thick and is comprised to paralic and shelfal facies turn, make up the 13 genetic packages (i.e., stratigraphic sequences) of the total marine section. Second-order eustatic oscillations of 3.5-5.0-m.y. duration dictated the paleogeographic (depositional) strike and the characteristics of lateral and vertical facies relations along paleogeographic strike. Third-order sea level oscillations (0.5-3.5 m.y.) are related to either eustasy or regional tectonics. Oscillations driven by eustasy produced stratigraphic breaks with appreciable relief, significant regional paleogeographic reorganizations, increased lateral and vertical facies entropy, and notable faunal changes. Stratigraphy of tectonically induced third-order oscillations generally lacks most or all of these features. Fourth-order sea level oscillations (less than 0.5 m.y.) are related most closely to minor regional tectonic adjustments coeval with the onset of episodic, Farallon-North American plate interactions. the episodic (rather than periodic) nature of fourth-order shelfal parasequences in the area, their fining-upward textural signature, characteristic transitional benthic-to-pelagic fossil record, and stratigraphic correlations with thin, prograding clastic tongues (paralic facies) collectively demonstrate a non-Milankovitch origin of the shelfal parasequences.

  9. Impact of relative sea level and rapid climate changes on the architecture and lithofacies of the Holocene Rhone subaqueous delta (Western Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Fanget, Anne-Sophie; Berné, Serge; Jouet, Gwénaël; Bassetti, Maria-Angela; Dennielou, Bernard; Maillet, Grégoire M.; Tondut, Mathieu

    2014-05-01

    The modern Rhone delta in the Gulf of Lions (NW Mediterranean) is a typical wave-dominated delta that developed after the stabilization of relative sea level following the last deglacial sea-level rise. Similar to most other deltas worldwide, it displays several stacked parasequences and lobes that reflect the complex interaction between accommodation, sediment supply and autogenic processes on the architecture of a wave-dominated delta. The interpretation of a large set of newly acquired very high-resolution seismic and sedimentological data, well constrained by 14C dates, provides a refined three-dimensional image of the detailed architecture (seismic bounding surfaces, sedimentary facies) of the Rhone subaqueous delta, and allows us to propose a scenario for delta evolution during the last deglaciation and Holocene. The subaqueous delta consists of “parasequence-like” depositional wedges, a few metres to 20-30 m in thickness. These wedges first back-stepped inland toward the NW in response to combined global sea-level rise and overall westward oceanic circulation, at a time when sediment supply could not keep pace with rapid absolute (eustatic) sea-level rise. At the Younger Dryas-Preboreal transition, more rapid sea-level rise led to the formation of a major flooding surface (equivalent to a wave ravinement surface). After stabilization of global sea level in the mid-Holocene, accommodation became the leading factor in controlling delta architecture. An eastward shift of depocentres occurred, probably favoured by higher subsidence rate within the thick Messinian Rhone valley fill. The transition between transgressive (backstepping geometry) and regressive (prograding geometry) (para)sequences resulted in creation of a Maximum Flooding Surface (MFS) that differs from a “classical” MFS described in the literature. It consists of a coarse-grained interval incorporating reworked shoreface material within a silty clay matrix. This distinct lithofacies

  10. Distinguishing Between Natural and Anthropogenic Part of Sea Level Trends

    NASA Astrophysics Data System (ADS)

    Becker, M.; Karpytchev, M.; Lennartz-Sassinek, S.

    2014-12-01

    Detection and attribution of human influence on sea level rise are important topics that have not yet been explored in depth. From the perspective of assessing the contribution of human activities to climate changes, the sea level drivers can be partitioned in anthropogenic and natural forcing. In this study we try to answer the following two questions: (1) How large a sea level trend could be expected as result of natural internal variability? (2) Whether the sea level changes observed over the past century were natural in origin. We suppose that natural behavior of sea level consists of increases and decreases occurring with frequencies following a power law distribution and the monthly sea level records are power law long-term correlated time series. Then we search for the presence of unnatural external sea level trend by applying statistics of Lennartz and Bunde [2009]. We estimate the minimum anthropogenic sea level trend as a lower bound of statistically significant external sea level trend in the longest tide-gauge records worldwide. We apply this new method to distinguish between the trend-like natural oscillations and the external trends in the longest available sea level records and in global mean sea level reconstructions. The results show that the long-term persistence impacts strongly on sea level rise estimation. We provide statistical evidences that the observed sea level changes, at global and regional scales, are beyond its natural internal variability and cannot be explained without human influence. We found that sea level change during the past century contains an external component at 99% significance level in two thirds of the available longest tidal records worldwide. The anthropogenic sea level trend is about 1 mm/yr in global sea level reconstructions that is more than half of the total observed sea level trend during the XXth century, which is about 1.7 mm/yr. This work provides the first estimate of the minimal anthropogenic contribution

  11. Sea level trends for all sections of the Baltic Sea coastline

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Høyer, Jacob L.; Suursaar, Ülo; Knudsen, Per; She, Jun

    2016-04-01

    To better understand influence of sea level rise on societal vulnerability and coastal erosion processes, it is important to know the sea level trend. The coastline of the Baltic Sea is not uniformly exposed, and therefore we will determine the sea level trend of the last 10, 50 and 100 years for all sections of the coastline. The observational record of sea level in the Baltic Sea is quite unique with several records of more than 100 years of data. However, the information is confined to the tide gauge locations. Here, we utilize a statistical method based on least squares regression and originally developed for short term sea level variability (Madsen et al. 2015, JGR, doi:10.1002/2015JC011070) to spread out the sea level information from selected tide gauges to all sections of the Baltic Sea coast. Monthly mean tide gauge observations are retrieved from PSMSL and supplemented with Estonian observations. The spatial distribution of the sea level is obtained from model reanalysis from the Copernicus Marine Service and satellite altimetry observations and land rise information is taken into account. Results are validated against independent tide gauges, providing a consistent record of 20th century sea level trends and variability, including uncertainties, for the entire Baltic Sea coastline. This work is sponsored by the EMODnet project Baltic Checkpoint.

  12. Sea-level rise and coastal wetlands.

    PubMed

    Blankespoor, Brian; Dasgupta, Susmita; Laplante, Benoit

    2014-12-01

    This paper seeks to quantify the impact of a1-m sea-level rise on coastal wetlands in 86 developing countries and territories. It is found that approximately 68 % of coastal wetlands in these countries are at risk. A large percentage of this estimated loss is found in Europe and Central Asia, East Asia, and the Pacific, as well as in the Middle East and North Africa. A small number of countries will be severely affected. China and Vietnam(in East Asia and the Pacific), Libya and Egypt (in the Middle East and North Africa), and Romania and Ukraine (in Europe and Central Asia) will bear most losses. In economic terms, the loss of coastal wetlands is likely to exceed $703 million per year in 2000 US dollars.

  13. Sea Level Rise and Decadal Variations in the Ligurian Sea Inferred from the Medimaremetre Measurements.

    NASA Astrophysics Data System (ADS)

    Karpytchev, M.; Coulomb, A.; Vallee, M.

    2015-12-01

    Estimations of sea level rise over the last centuries are mostly based on the rare historical sea level records from tide gauge stations usually designed for navigational purposes. In this study, we examine the quality of sea level measurements performed by a mean sea level gauge operated in Nice from 1887 to 1909 and transferred to the nearby town of Villefranche-sur-Mer in 1913 where it stayed in operation untill 1974. The mean sea level gauges, called medimaremetres, were invented for geodetic studies and installed in many French ports since the end of the XIX century. By construction, the medimaremetre was connected to the sea through a porous porcelain crucible in order to filter out the tides and higher frequency sea level oscillations. Ucontrolled properties of the crucible and some systematic errors made the medimaremetre data to be ignored in the current sea level researches. We demonstrate that the Nice-Villefranche medimaremetre measurements are coherent with two available historical tide gauge records from Marseille and Genova and a new century-scale sea level series can be build up by combining the medimaremetre data with the those recorded by a tide gauge operating in Nice since the 1980s. We analyse the low frequency variabilities in Marseille, Nice-Villefranche and Genova and get new insights on the decadal sea level variations in the Ligurian Sea since the end of the XIX century.

  14. Relative sea level and coastal environments in arctic Alaska during Marine Isotope Stage 5

    NASA Astrophysics Data System (ADS)

    Farquharson, L. M.; Mann, D. H.; Jones, B. M.; Rittenour, T. M.; Grosse, G.; Groves, P.

    2015-12-01

    Marine Isotope Stage (MIS) 5 was characterized by marked fluctuations in climate, the warmest being MIS 5e (124-119 ka) when relative sea level (RSL) stood 2-10 m higher than today along many coastlines. In northern Alaska, marine deposits now 5-10 m above modern sea level are assigned to this time period and termed the Pelukian transgression (PT). Complicating this interpretation is the possibility that an intra-Stage 5 ice shelf extended along the Alaskan coast, causing isostatic depression along its grounded margins, which caused RSL highs even during periods of low, global RSL. Here we use optically stimulated luminescence (OSL) to date inferred PT deposits on the Beaufort Sea coastal plain. A transition from what we interpret to be lagoonal mud to sandy tidal flat deposits lying ~ 2.75 m asl dates to 113+/-18 ka. Above this, a 5-m thick gravelly barrier beach dates to 95 +/- 20 ka. This beach contains well-preserved marine molluscs, whale vertebrae, and walrus tusks. Pleistocene-aged ice-rich eolian silt (yedoma) blanket the marine deposits and date to 57.6 +/-10.9 ka. Our interpretation of this chronostratigraphy is that RSL was several meters higher than today during MIS 5e, and lagoons or brackish lakes were prevalent. Gravel barrier beaches moved onshore as local RSL rose further after MIS 5e. The error range of the OSL age of the barrier-beach unit spans the remaining four substages of MIS 5; however, the highstand of RSL on this arctic coastline appears to occurr after the warmest part of the last interglacial and appears not to be coeval with the eustatic maximum reached at lower latitudes during MIS 5. One possibility is that RSL along the Beaufort Sea coast was affected by isostatic depression caused by an ice shelf associated with widespread, intra-Stage 5 glaciation that was out of phase with lower latitude glaciation and whose extent and timing remains enigmatic.

  15. Dinoflagellate cysts as indicators of palaeoenvironmental and sea-level change: the Late Cenomanian - Early Coniacian (Cretaceous) of Europe

    NASA Astrophysics Data System (ADS)

    Olde, Kate; Jarvis, Ian; Pearce, Martin; Tocher, Bruce

    2014-05-01

    The Late Cretaceous represented a period of greenhouse climate of Earth history, and was characterised by high temperatures, high atmospheric CO2 and high eustatic sea level, with large areas of shallow, warm, epicontinental sea. Understanding the dynamics of the Late Cretaceous climate is important for understanding the Earth System and the impact of modern climate change. The productive Late Cretaceous oceans led to the deposition of a large portion of the world's oil and gas resources, so reconstruction of depositional environments and refinement of stratigraphic correlation are important for the petroleum industry. Dinoflagellates were a prolific and diverse group within the phyto- and zooplankton throughout Late Cretaceous oceans, and their cysts display good preservation across different facies, and so are a good group for biostratigraphic and palaeoenvironmental study. Selected results from a high-resolution quantitative study of the palynology from 5 European Upper Cenomanian to the Lower Coniacian (Upper Cretaceous) sections are summarised, along with their carbon stable-isotope chemostratigraphy. The sections are from a range of palaeolatitudes and basins, including the North Sea Basin, the Anglo-Paris Basin, the Bohemian Basin, the Polish Trough and the Vocontian Basin. Palynological assemblages differ between sections in the concentration of palynomorphs, proportions of terrestrial and marine palynomorphs, and in the diversity and varying proportions of species of dinoflagellate cysts (dinocysts). Dinocyst distribution is considered to have been controlled largely by nutrient levels, but was also impacted by temperature, sea level, and water mass changes. Influxes of certain species are related to changes in salinity, changes in temperature, and water mass change, and increased communication between basins. High dinocyst abundance, and particularly a high proportion of peridinioid cysts (which are thought to be derived from eutrophy

  16. Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago.

    PubMed

    Deschamps, Pierre; Durand, Nicolas; Bard, Edouard; Hamelin, Bruno; Camoin, Gilbert; Thomas, Alexander L; Henderson, Gideon M; Okuno, Jun'ichi; Yokoyama, Yusuke

    2012-03-28

    Past sea-level records provide invaluable information about the response of ice sheets to climate forcing. Some such records suggest that the last deglaciation was punctuated by a dramatic period of sea-level rise, of about 20 metres, in less than 500 years. Controversy about the amplitude and timing of this meltwater pulse (MWP-1A) has, however, led to uncertainty about the source of the melt water and its temporal and causal relationships with the abrupt climate changes of the deglaciation. Here we show that MWP-1A started no earlier than 14,650 years ago and ended before 14,310 years ago, making it coeval with the Bølling warming. Our results, based on corals drilled offshore from Tahiti during Integrated Ocean Drilling Project Expedition 310, reveal that the increase in sea level at Tahiti was between 12 and 22 metres, with a most probable value between 14 and 18 metres, establishing a significant meltwater contribution from the Southern Hemisphere. This implies that the rate of eustatic sea-level rise exceeded 40 millimetres per year during MWP-1A.

  17. Using δ18O of Conodont Apatite and Sequence Stratigraphy to Understand Early Triassic (Smithian) Sea-Level Change

    NASA Astrophysics Data System (ADS)

    Yurchyk, S.; Elrick, M.; Atudorei, V.

    2009-12-01

    The Early Triassic climate is conventionally interpreted to have been warm and ice-free. During this time, three globally recognized depositional sequences developed in response to My-scale eustatic sea-level changes. The rates of My-scale sea-level rise and fall are too fast to attribute to changes in mid-ocean ridge activity and too slow to attribute to typical ~20-400 ky orbital cycles that drive glacio-eustasy. Previous studies in the Middle Devonian, Late Cretaceous, and Middle Eocene greenhouse climates have suggested that significant glacio-eustatic sea-level changes were responsible for sequence development. This suggests that these particular greenhouse periods were not uniformly warm and ice-free. We are testing the hypothesis that My- and orbital-scale sea-level changes in the Early Triassic (Smithian) were driven by glacio- and/or thermo-eustasy. To test this hypothesis, Smithian marine successions from two localities in the western United States (Lower Thaynes Formation) were described on a bed-by-bed basis to provide facies and depositional environment interpretations, as well as put the sections into a sequence stratigraphic framework. Samples were collected from both locations for high-resolution (~1-10 m) oxygen isotopic analysis of conodont apatite. Conodont elements are excellent biostratigraphic indicators and the apatite is less susceptible to diagenetic alteration than carbonate minerals, making conodont apatite a reliable proxy for determining changes in ice volume and seawater temperatures in deep time. In northeastern Utah (Weber Canyon), the Smithian sequence (~240 m) is composed of a mixed carbonate-siliciclastic lowstand systems tract (>40 m) and transgressive systems tract (~110 m), a black shale maximum flooding zone (~15 m), and a carbonate-dominated highstand systems tract (~75 m). In western Utah (Confusion Range), the sequence is composed of a coarse-grained, carbonate-dominated transgressive systems tract (>40 m) and a mixed

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

    PubMed Central

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

    2014-01-01

    There is observational evidence that global sea level is rising and there is concern that the rate of rise will increase, significantly threatening coastal communities. However, considerable debate remains as to whether the rate of sea level rise is currently increasing and, if so, by how much. Here we provide new insights into sea level accelerations by applying the main methods that have been used previously to search for accelerations in historical data, to identify the timings (with uncertainties) at which accelerations might first be recognized in a statistically significant manner (if not apparent already) in sea level records that we have artificially extended to 2100. We find that the most important approach to earliest possible detection of a significant sea level acceleration lies in improved understanding (and subsequent removal) of interannual to multidecadal variability in sea level records. PMID:24728012

  19. Global sea-level changes during the past century

    NASA Technical Reports Server (NTRS)

    Gornitz, Vivien; Lebedeff, Sergej

    1987-01-01

    A novel technique, initially developed for climate studies, is used to reevaluate the estimate of relative sea-level change over the past century. The technique produces a composite regional average sea-level curve from the tide-gage data of individual stations. The effects of glacioisostasy and long-term tectonism are accounted for using late Holocene sea-level indicators. Along the east coast of North America, an apparent maximum sea-level rise is detected in both tide-gage and late Holocene sea-level indicators between Chesapeake Bay and New Jersey. Sea-level changes in western North America reveal greater spatial variations than for the east coast, which can be related to more active tectonism in California and British Columbia and to strong localized isostatic rebound in Alaska.

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

    PubMed

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

    2014-04-14

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

  1. Global sea level trend in the past century

    NASA Technical Reports Server (NTRS)

    Gornitz, V.; Lebedeff, S.; Hansen, J.

    1982-01-01

    Data derived from tide-gauge stations throughout the world indicate that the mean sea level rose by about 12 centimeters in the past century. The sea level change has a high correlation with the trend of global surface air temperature. A large part of the sea level rise can be accounted for in terms of the thermal expansion of the upper layers of the ocean. The results also represent weak indirect evidence for a net melting of the continental ice sheets.

  2. Carbon-isotope composition of Lower Cretaceous fossil wood: Ocean-atmosphere chemistry and relation to sea-level change

    SciTech Connect

    Groecke, D.R.; Hesselbo, S.P.; Jenkyns, H.C.

    1999-02-01

    The carbon-isotope composition of fossil wood fragments, collected through a biostratigraphically well-constructed Aptian (Lower Cretaceous) shallow-marine siliciclastic succession on the Isle of Wight, southern Britain, shows distinct variations with time. The results indicate that the stratigraphic signature of {delta}{sup 13}C{sub wood} through the Aptian was influenced primarily by fluctuations in the isotopic composition of CO{sub 2} in the global ocean-atmosphere system, as registered in marine carbonates elsewhere, and was not governed by local paleoenvironmental and/or paleoecological factors. Negative and positive excursions in {delta}{sup 13}C{sub wood} through the lower Aptian occur in phase with inferred transgressions and regressions, respectively -- a pattern that contrasts with that observed in many previous studies for different time intervals. The relationship between {delta}{sup 13}C variations and relative sea-level change is tentatively interpreted as a response to various climatic and eustatic factors, relating to rapid sea-floor spreading, thermal uplift of ocean floor, emplacement of plateaus, volcanic CO{sub 2} emissions, weathering, and sedimentary rate.

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

    SciTech Connect

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

    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.

  4. Demographic responses to sea level rise in California

    SciTech Connect

    Constable, A. |; Van Arsdol, M.D. Jr.; Sherman, D.J.; Wang, J.; McMullin-Messier, P.A.; Rollin, L.

    1996-12-31

    Human consequences of sea level rise in California coastal counties reflect increasing population densities. Populations of coastal counties potentially affected by sea level rise are projected to increase from 26.2 million persons in 1990 to 63.3 million persons in 2040. Urbanization dominates Los Angeles and the South Coast and San Francisco Bay and Delta regions. California shoreline populations subject to potential disruption impacts of sea level rise are increasing rapidly. Enhanced risk zones for sea level rise are specified for the Oxnard Plain of Ventura County on the south coast of California. Four separate sea level rise scenarios are considered: (1) low (sea level rise only); (2) moderate (adding erosion); (3) high (adding erosion and storm surges); and (4) a maximum case, a 3 m enhanced risk zone. Population impacts are outlined for the 3 m zone. More serious impacts from storm surges are expected than from sea level rise and erosion. Stakeholders who support or oppose policies which may expose populations to sea level rise include energy, commercial, financial, industrial, public agency, private interest and governmental organizations. These organizations respond to extreme events from differing positions. Vested interests determine the degree of mitigation employed by stakeholders to defer impacts of sea level rise.

  5. Estimation of Holocene Land Movement and Sea Level Changes in Southwest Scandinavia - Results From Interpretation of Relative Sea Level Curves

    NASA Astrophysics Data System (ADS)

    Nielsen, L.; Hede, M.; Clemmensen, L. B.; Morten Hansen, J.; Noe-Nygaard, N.; Sander, L.; Bendixen, M.; Kroon, A.; Murray, A. S.; Pejrup, M.

    2013-12-01

    Relative sea level curves from different localities in Denmark, southwest Scandinavia, are used for estimation of Holocene vertical land movement and absolute sea level variations in the gateway between the North Sea and the Baltic Sea. Two previous independent studies conducted in the area show that ground penetrating radar reflection images of internal beach ridge and swale architecture form a strong basis for estimation of relative sea level variation. Sediments are dated using optically stimulated luminescence (OSL); this shows that the beach ridges and swales were last exposed to daylight between ~6500 and 0 years ago. Time periods with characteristic changes in the rate of relative sea level change are identified at different localities. The observed relative sea level change rates differ in the study area, mainly because the different localities have experienced different isostatic rebound since the latest glaciation. Variations in uplift rates and absolute sea level change for the region are estimated by inversion of the observed relative sea level changes. The values obtained for the different time periods put constraints on absolute sea level variation during the Holocene and have implications for our understanding of the lithosphere's temporal response to the unloading caused by melting of the thick ice sheet formed during the latest glaciation in Scandinavia.

  6. Timing and Estimates of Plio-Pleistocene Sea-Level Highstands from the Republic of South Africa (RSA)

    NASA Astrophysics Data System (ADS)

    Hearty, Paul; Raymo, Maureen; Sandstrom, Michael; Rovere, Alessio; O'Leary, Michael

    2016-04-01

    The rapid rise in atmospheric CO2 exceeding 400 ppmv is driving an urgent need to better understand past sea level, ice sheet dynamics, and climate change associated with past warmer geological intervals. The LR04 record reveals sustained intervals during the Pliocene (5.6-2.6 Ma) when δ18O exceeded the present levels, indicating a possible decrease in the volume of polar ice sheets. Other shorter intervals of likely decreased ice volume occur during Pleistocene interglacials including MIS 5e, 11, 31, and 37.Here we focus on the middle Pliocene warm period (MPWP; 3.3 to 2.9 Ma), an interval during which Earth experienced CO2 levels around 400 ppmv (Fedorov et al., 2013). The intra-plate coastal margin of western South Africa, a region of relative tectonic stability and relative insensitivity to uncertainty in mantle viscosity as is effects corrections for glacial isostatic adjustment, is a promising region for deriving estimates of eustatic sea level (ESL; thus ice volumes) at the end of the MPWP (Rovere et al., 2014). During a field expedition covering several thousand kilometres along coastlines of western and southern coasts of RSA, we documented the stratigraphy, geomorphology, and geochronology of Pliocene and Pleistocene shorelines with differential GPS providing decimeter scale accuracy to stratigraphic contacts and sea-level indicators. From about twenty sites, precise elevations (as yet uncorrected for GIA) of multiple sea stands were recorded. Strontium isotopes were used to date the shell material from many of the marine sites, but only three sites yielded reliable age data that passed screening criteria for diagenesis. The oldest shoreline evidence, from Cliffs Point on the west coast near the Olifants River, is observed at 34.9 ±0.2 m asl and yields an age 4.70 ± 0.20 Ma; a younger shoreline from the southern coast Bredasdorp site is observed at >24.0 ± 1.5 m asl and yields ages from 3.00 ± 0.45 to 3.55 ± 0.31 Ma, the interval of the MPWP. . A

  7. Detecting anthropogenic footprints in sea level rise

    PubMed Central

    Dangendorf, Sönke; Marcos, Marta; Müller, Alfred; Zorita, Eduardo; Riva, Riccardo; Berk, Kevin; Jensen, Jürgen

    2015-01-01

    While there is scientific consensus that global and local mean sea level (GMSL and LMSL) has risen since the late nineteenth century, the relative contribution of natural and anthropogenic forcing remains unclear. Here we provide a probabilistic upper range of long-term persistent natural GMSL/LMSL variability (P=0.99), which in turn, determines the minimum/maximum anthropogenic contribution since 1900. To account for different spectral characteristics of various contributing processes, we separate LMSL into two components: a slowly varying volumetric component and a more rapidly changing atmospheric component. We find that the persistence of slow natural volumetric changes is underestimated in records where transient atmospheric processes dominate the spectrum. This leads to a local underestimation of possible natural trends of up to ∼1 mm per year erroneously enhancing the significance of anthropogenic footprints. The GMSL, however, remains unaffected by such biases. On the basis of a model assessment of the separate components, we conclude that it is virtually certain (P=0.99) that at least 45% of the observed increase in GMSL is of anthropogenic origin. PMID:26220773

  8. Wave transformation across coral reefs under changing sea levels

    NASA Astrophysics Data System (ADS)

    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

  9. Numerical study of the Azov Sea level seiche oscillations

    NASA Astrophysics Data System (ADS)

    Matishov, G. G.; Inzhebeikin, Yu. I.

    2009-08-01

    Seiche oscillations of the Azov Sea level are studied on the basis of the developed two-dimensional numerical hydrodynamic model grounded on the shallow water theory and recent data on the morphometric characteristics of the Sea of Azov. Frequency and spatial characteristics of the first five modes corresponding to seiche oscillations of the Azov Sea level are computed. It is shown that the frequency and spatial characteristics of the first five modes obtained for the Sea of Azov level changes correspond to seiche oscillations. The calculated parameters are compared with the field observations, which show their realistic character.

  10. A search for scale in sea-level studies

    USGS Publications Warehouse

    Larsen, C.E.; Clark, I.

    2006-01-01

    Many researchers assume a proportional relationship among the atmospheric CO2 concentration, temperature, and sea level. Thus, the rate of sea-level rise should increase in concert with the documented exponential increase in CO2. Although sea surface temperature has increased in places over the past century and short-term sea level rose abruptly during the 1990s, it is difficult to demonstrate a proportional relationship using existing geologic or historic records. Tide gauge records in the United States cover too short a time interval to verify acceleration in the rate of sea-level rise, although multicentury tide gauge and staff records from the Netherlands and Sweden suggest a mid-19th-century acceleration in sea-level rise. Reconstructions of sea-level changes for the past 1000 years derived using benthic foraminifer data from salt marshes along the East Coast of the United States suggest an increased rate of relative sea-level rise beginning in the 1600s. Geologic records of relative sea-level rise for the past 6000 years are available for several sites along the US East Coast from 14C-dated basal peat below salt marshes and estuarine sediments. When these three scales of sea-level variation are integrated, adjusted for postglacial isostatic movement, and replotted, the range of variation in sea level suggested by basal peat ages is within ??1 meter of the long-term trend. The reconstruction from Long Island Sound data shows a linear rise in sea level beginning in the mid-1600s at a rate consistent with the historic record of mean high water. Long-term tide gauge records from Europe and North America show similar trends since the mid-19th century. There is no clear proportional exponential increase in the rate of sea-level rise. If proportionality exists among sea level, atmospheric CO2, and temperature, there may be a significant time lag before an anthropogenic increase in the rate of sea-level rise occurs.

  11. Impact of sea-level rise on sea water intrusion in coastal aquifers.

    PubMed

    Werner, Adrian D; Simmons, Craig T

    2009-01-01

    Despite its purported importance, previous studies of the influence of sea-level rise on coastal aquifers have focused on specific sites, and a generalized systematic analysis of the general case of the sea water intrusion response to sea-level rise has not been reported. In this study, a simple conceptual framework is used to provide a first-order assessment of sea water intrusion changes in coastal unconfined aquifers in response to sea-level rise. Two conceptual models are tested: (1) flux-controlled systems, in which ground water discharge to the sea is persistent despite changes in sea level, and (2) head-controlled systems, whereby ground water abstractions or surface features maintain the head condition in the aquifer despite sea-level changes. The conceptualization assumes steady-state conditions, a sharp interface sea water-fresh water transition zone, homogeneous and isotropic aquifer properties, and constant recharge. In the case of constant flux conditions, the upper limit for sea water intrusion due to sea-level rise (up to 1.5 m is tested) is no greater than 50 m for typical values of recharge, hydraulic conductivity, and aquifer depth. This is in striking contrast to the constant head cases, in which the magnitude of salt water toe migration is on the order of hundreds of meters to several kilometers for the same sea-level rise. This study has highlighted the importance of inland boundary conditions on the sea-level rise impact. It identifies combinations of hydrogeologic parameters that control whether large or small salt water toe migration will occur for any given change in a hydrogeologic variable.

  12. Sea-level variability in the Mediterranean Sea from altimetry and tide gauges

    NASA Astrophysics Data System (ADS)

    Bonaduce, A.; Pinardi, N.; Oddo, P.; Spada, G.; Larnicol, G.

    2016-11-01

    Sea-level variability in the Mediterranean Sea was investigated by means of in-situ (tide-gauge) and satellite altimetry data over a period spanning two decades (from 1993 to 2012). The paper details the sea-level variations during this time period retrieved from the two data sets. Mean sea-level (MSL) estimates obtained from tide-gauge data showed root mean square differences (RMSDs) in the order of 40-50 % of the variance of the MSL signal estimated from satellite altimetry data, with a dependency on the number and quality of the in-situ data considered. Considering the individual time-series, the results showed that coastal tide-gauge and satellite sea-level signals are comparable, with RMSDs that range between 2.5 and 5 cm and correlation coefficients up to the order of 0.8. A coherence analysis and power spectra comparison showed that two signals have a very similar energetic content at semi-annual temporal scales and below, while a phase drift was observed at higher frequencies. Positive sea-level linear trends for the analysis period were estimated for both the mean sea-level and the coastal stations. From 1993 to 2012, the mean sea-level trend (2.44± 0.5 mm year^{-1}) was found to be affected by the positive anomalies of 2010 and 2011, which were observed in all the cases analysed and were mainly distributed in the eastern part of the basin. Ensemble empirical mode decomposition showed that these events were related to the processes that have dominant periodicities of ˜10 years, and positive residual sea-level trend were generally observed in both data-sets. In terms of mean sea-level trends, a significant positive sea-level trend (>95 %) in the Mediterranean Sea was found on the basis of at least 15 years of data.

  13. Sea-level variability in the Mediterranean Sea from altimetry and tide gauges

    NASA Astrophysics Data System (ADS)

    Bonaduce, Antonio; Pinardi, Nadia; Oddo, Paolo; Spada, Giorgio; Larnicol, Gilles

    2016-04-01

    Sea-level variability in the Mediterranean Sea was investigated by means of in-situ (tide-gauge) and satellite altimetry data over a period spanning two decades (from 1993 to 2012). The paper details the sea-level variations during this time period retrieved from the two data sets. Mean sea-level (MSL) estimates obtained from tide-gauge data showed root mean square differences (RMSDs) in the order of 40-50 % of the variance of the MSL signal estimated from satellite altimetry data, with a dependency on the number and quality of the in-situ data considered. Considering the individual time-series, the results showed that coastal tide-gauge and satellite sea-level signals are comparable, with RMSDs that range between 2.5 and 5 cm and correlation coefficients up to the order of 0.8. A coherence analysis and power spectra comparison showed that two signals have a very similar energetic content at semi-annual temporal scales and below, while a phase drift was observed at higher frequencies. Positive sea-level linear trends for the analysis period were estimated for both the mean sea-level and the coastal stations. From 1993 to 2012, the mean sea-level trend (2.44 ± 0.5 mm yr-1) was found to be affected by the positive anomalies of 2010 and 2011, which were observed in all the cases analysed and were mainly distributed in the eastern part of the basin. Ensemble Empirical Mode Decomposition (EEMD) showed that these events were related to the processes that have dominant periodicities of ˜10 years, and positive residual sea-level trend were generally observed in both data-sets. In terms of mean sea-level trends, a significant positive sea-level trend (> 95 %) in the Mediterranean Sea was found on the basis of at least 15 years of data.

  14. Late Holocene sea-level change in Arctic Norway

    NASA Astrophysics Data System (ADS)

    Barnett, Robert L.; Gehrels, W. Roland; Charman, Dan J.; Saher, Margot H.; Marshall, William A.

    2015-01-01

    Relative sea-level data from the pre-industrial era are required for validating geophysical models of glacio-isostatic adjustment as well as for testing models used to make sea-level predictions based on future climate change scenarios. We present the first late Holocene (past ˜3300 years) relative sea-level reconstruction for northwestern Norway based on investigations in South Hinnøya in the Vesterålen - Lofoton archipelago. Sea-level changes are reconstructed from analyses of salt-marsh and estuarine sediments and the micro-organisms (foraminifera and testate amoebae) preserved within. The 'indicative meaning' of the microfauna is established from their modern distributions. Records are dated by radiocarbon, 201Pb, 137Cs and chemostratigraphical analyses. Our results show a continuous relative sea-level decline of 0.7-0.9 mm yr-1 for South Hinnøya during the late Holocene. The reconstruction extends the relative sea-level trend recorded by local tide gauge data which is only available for the past ˜25 years. Our reconstruction demonstrates that existing models of shoreline elevations and GIA overpredict sea-level positions during the late Holocene. We suggest that models might be adjusted in order to reconcile modelled and reconstructed sea-level changes and ultimately improve understanding of GIA in Fennoscandia.

  15. Uncertainties in sea level reconstructions due to GIA corrections

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    We use 1277 tide gauge records since 1807 to compose a global sea level reconstruction and analyse the evolution of sea level trend and acceleration. There is a good agreement between the rate of sea level rise (3.2 mm/yr) calculated from satellite altimetry and the rate of 3.1 mm/yr from tide gauge based reconstruction for the overlapping time period (1993-2009). The new reconstruction suggests a linear trend of 1.9 mm/yr during the 20th century, with only 1.5 mm/yr since 1960. Regional linear trends for 14 ocean basins since 1960 show the fastest sea level rise for the Arctic (3.8 mm/yr), Antarctica (3.5 mm/yr) and North West Pacific region (3.3 mm/yr). Choice of GIA correction is critical in the trends for the local and regional sea level, introducing up to 6 mm/yr uncertainties for individual tide gauge records, up to 2 mm/yr for regional curves and up to 0.8 mm/yr in global sea level reconstruction. We calculate an acceleration of 0.02 mm/yr in global sea level (1807-2010). In comparison the steric component of sea level shows and acceleration of 0.006 mm/yr 2 and mass loss of glaciers accelerates at 0. 003 mm/yr2 over 200 year long time series.

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

    NASA Astrophysics Data System (ADS)

    Vilibic, Ivica; Sepic, Jadranka

    2016-04-01

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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    ERIC Educational Resources Information Center

    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…

  19. Arctic Sea Level During the Satellite Altimetry Era

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Arctic Sea Level During the Satellite Altimetry Era

    NASA Astrophysics Data System (ADS)

    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.

  2. Future Extreme Sea Level Variability in the Tropical Pacific

    NASA Astrophysics Data System (ADS)

    Widlansky, M. J.; Timmermann, A.; Stuecker, M. F.; McGregor, S.; Cai, W.; Chikamoto, Y.

    2014-12-01

    During strong El Niño events, sea level drops around tropical western Pacific islands by up to 20-30 cm. Such extreme events (referred to in Samoa as 'taimasa') expose shallow reefs, thereby damaging associated coastal ecosystems and contributing to the formation of 'flat topped coral heads' often referred to as microatolls. We show that during the termination of strong El Niño events, a southward movement of weak trade winds prolongs extreme low sea levels in the southwestern Pacific. Whereas future sea levels are projected to gradually rise, recent modeling evidence suggests that the frequency of strong El Niño events (which alter local trade winds and sea level) is very likely to increase with greenhouse warming. Such changes could exacerbate El Niño-related sea level drops, especially in the tropical southwestern Pacific. Using present-generation coupled climate models forced with increasing greenhouse-gas concentrations, we assess how the interplay between global mean sea level rise, on one hand, and more frequent interannual sea level drops, on the other, will affect future coastal sea levels in the tropical Pacific.

  3. Time of emergence for regional sea-level change

    NASA Astrophysics Data System (ADS)

    Lyu, Kewei; Zhang, Xuebin; Church, John A.; Slangen, Aimée B. A.; Hu, Jianyu

    2014-11-01

    Determining the time when the climate change signal from increasing greenhouse gases exceeds and thus emerges from natural climate variability (referred to as the time of emergence, ToE) is an important climate change issue. Previous ToE studies were mainly focused on atmospheric variables. Here, based on three regional sea-level projection products available to 2100, which have increasing complexity in terms of included processes, we estimate the ToE for sea-level changes relative to the reference period 1986-2005. The dynamic sea level derived from ocean density and circulation changes alone leads to emergence over only limited regions. By adding the global-ocean thermal expansion effect, 50% of the ocean area will show emergence with rising sea level by the early-to-middle 2040s. Including additional contributions from land ice mass loss, land water storage change and glacial isostatic adjustment generally enhances the signal of regional sea-level rise (except in some regions with decreasing total sea levels), which leads to emergence over more than 50% of the ocean area by 2020. The ToE for total sea level is substantially earlier than that for surface air temperature and exhibits little dependence on the emission scenarios, which means that our society will face detectable sea-level change and its potential impacts earlier than surface air warming.

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

    PubMed

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

    2015-09-01

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

  5. Estuaries May Face Increased Parasitism as Sea Levels Rise

    NASA Astrophysics Data System (ADS)

    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. Future extreme sea level seesaws in the tropical Pacific

    PubMed Central

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

    2015-01-01

    Global mean sea levels are projected to gradually rise in response to greenhouse warming. However, on shorter time scales, modes of natural climate variability in the Pacific, such as the El Niño–Southern Oscillation (ENSO), can affect regional sea level variability and extremes, with considerable impacts on coastal ecosystems and island nations. How these shorter-term sea level fluctuations will change in association with a projected increase in extreme El Niño and its atmospheric variability remains unknown. Using present-generation coupled climate models forced with increasing greenhouse gas concentrations and subtracting the effect of global mean sea level rise, we find that climate change will enhance El Niño–related sea level extremes, especially in the tropical southwestern Pacific, where very low sea level events, locally known as Taimasa, are projected to double in occurrence. Additionally, and throughout the tropical Pacific, prolonged interannual sea level inundations are also found to become more likely with greenhouse warming and increased frequency of extreme La Niña events, thus exacerbating the coastal impacts of the projected global mean sea level rise. PMID:26601272

  7. Late Quaternary depositional history, Holocene sea-level changes, and vertical crustal movement, southern San Francisco Bay, California

    USGS Publications Warehouse

    Atwater, Brian F.; Hedel, Charles W.; Helley, Edward J.

    1977-01-01

    tectonic subsidence in less than 1.5 million years (<0.07 mm/yr) relative to the likely elevation of the lowest Pleistocene land surface; (2) the deepest Sangamon estuarine deposits subsided tectonically about 20–40 m in about 0.1 million years (0.2±0.1–0.4±0.1 mm/yr) relative to the assumed initial elevations of the thalwegs buried by these sediments; and (3) Holocene salt-marsh deposits have undergone about 5 m of tectonic and possibly isostatic subsidence in about 6,000 years (0.8±.0.7 mm/yr) relative to elevations which might be expected from eustatic sea-level changes alone.

  8. Global sea-level change during the next 10,000 years: the end of an icehouse?

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Because of the long life-time of atmospheric CO2, any realized future warming is likely to persist for many centuries to millennia. As a consequence, sea-level rise will continue on a multi-millennial timescale, especially from the slower components such as oceanic thermal expansion and above all, from melting of the Greenland and Antarctic ice sheets. The two polar ice sheets have the potential to produce a global eustatic sea-level rise of about 65 m, at least an order of magnitude larger than thermal expansion under extreme forcing scenarios. Other components contributing to sea-level change are the melting of glaciers and ice caps and haline contraction of the ocean from fresh water delivery from land ice, but are less important. We have made projections of future sea-level rise over the next 10,000 years with the Earth System Model of Intermediate Complexity LOVECLIM, which includes high resolution models of the Greenland and Antarctic ice sheets. Four different model parameter sets are considered to explore the model uncertainty. The climate forcing is based on prolonged Radiative Concentration Pathway (RCP) scenarios with an assumed exponential falloff for carbon dioxide concentrations according to global carbon cycle simulations. Six different forcing scenarios are constructed where the highest scenario includes a positive feedback due to the destabilization of methane hydrates and the subsequent emission of methane. By far the largest contribution in the global sea-level projections arises from the polar ice sheets. For the Greenland ice sheet, the ablation is larger than the accumulation for all forcing scenarios shortly after the start of the experiments. The ice sheet continuously melts and nearly disappears in all cases. The Antarctic ice sheet grows during the first decades under low to intermediate forcing scenarios due to increased accumulation. However, the spread between the different scenarios is very large. Under the highest prolonged RCP

  9. Continuous assimilation of simulated Geosat altimetric sea level into an eddy-resolving numerical ocean model. I - Sea level differences. II - Referenced sea level differences

    NASA Technical Reports Server (NTRS)

    White, Warren B.; Tai, Chang-Kou; Holland, William R.

    1990-01-01

    The optimal interpolation method of Lorenc (1981) was used to conduct continuous assimilation of altimetric sea level differences from the simulated Geosat exact repeat mission (ERM) into a three-layer quasi-geostrophic eddy-resolving numerical ocean box model that simulates the statistics of mesoscale eddy activity in the western North Pacific. Assimilation was conducted continuously as the Geosat tracks appeared in simulated real time/space, with each track repeating every 17 days, but occurring at different times and locations within the 17-day period, as would have occurred in a realistic nowcast situation. This interpolation method was also used to conduct the assimilation of referenced altimetric sea level differences into the same model, performing the referencing of altimetric sea sevel differences by using the simulated sea level. The results of this dynamical interpolation procedure are compared with those of a statistical (i.e., optimum) interpolation procedure.

  10. Improved estimates of global sea level change from Ice Sheets, glaciers and land water storage using GRACE

    NASA Astrophysics Data System (ADS)

    Velicogna, I.; Hsu, C. W.; Ciraci, E.; Sutterley, T. C.

    2015-12-01

    We use observations of time variable gravity from GRACE to estimate mass changes for the Antarctic and Greenland Ice Sheets, the Glaciers and Ice Caps (GIC) and land water storage for the time period 2002-2015 and evaluate their total contribution to sea level. We calculate regional sea level changes from these present day mass fluxes using an improved scaling factor for the GRACE data that accounts for the spatial and temporal variability of the observed signal. We calculate a separate scaling factor for the annual and the long-term components of the GRACE signal. To estimate the contribution of the GIC, we use a least square mascon approach and we re-analyze recent inventories to optimize the distribution of mascons and recover the GRACE signal more accurately. We find that overall, Greenland controls 43% of the global trend in eustatic sea level rise, 16% for Antarctica and 29% for the GIC. The contribution from the GIC is dominated by the mass loss of the Canadian Arctic Archipelago, followed by Alaska, Patagonia and the High Mountains of Asia. We report a marked increase in mass loss for the Canadian Arctic Archipelago. In Greenland, following the 2012 high summer melt, years 2013 and 2014 have slowed down the increase in mass loss, but our results will be updated with summer 2015 observations at the meeting. In Antarctica, the mass loss is still on the rise with increased contributions from the Amundsen Sea sector and surprisingly from the Wilkes Land sector of East Antarctica, including Victoria Land. Conversely, the Queen Maud Land sector experienced a large snowfall in 2009-2013 and has now resumed to a zero mass gain since 2013. We compare sea level changes from these GRACE derived mass fluxes after including the atmospheric and ocean loading signal with sea level change from satellite radar altimetry (AVISO) corrected for steric signal of the ocean using Argo measurements and find an excellent agreement in amplitude, phase and trend in these estimates

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Satellite Altimeter Observations of Black Sea Level Variations

    NASA Technical Reports Server (NTRS)

    Korotaev, G. K.; Saenko, O. A.; Koblinsky, C. J.

    1998-01-01

    Satellite altimeter data from TOPEX/POSEIDON and ERS-1 are used to examine seasonal and mesoscale variability of the Black Sea level. Consistent processing procedures of the altimeter measurements make it possible to determine the dynamical Black Sea level with an rms accuracy about 3 cm. It is shown that the Black Sea circulation intensifies in the winter-spring seasons and attenuates in summer-autumn. The seasonal variability of sea level is accompanied by a radiation of Rossby waves from the eastern coast of the basin. Mesoscale oscillations of the dynamical sea level are found to vary spatially and temporarily. Usually, strong eddy intensity is associated with instabilities of the Rim Current. Away from this circulation feature, in the deep basin, mesoscale variability is much smaller. Mesoscale variability has a strong seasonal signal, which is out of phase with the strength of the Rim Current.

  13. Using Sea Level Change as a Climate Indicator

    NASA Astrophysics Data System (ADS)

    Masters, D. S.; Nerem, R. S.

    2014-12-01

    Sea level rise is one the more important risks due to climate change. Multiple satellite altimeters flying on the same repeating ground track have allowed estimation of global and regional sea level for the past 20 years, and the time series has yielded information about how sea level is responding to climate change. Due to the duration, consistency, and inter-calibration of the altimeter measurements, the time series is now considered a climate data record. The time series has also shown the strong dependence of sea level on interannual signals such as the ENSO and PDO. Global mean sea level change as estimated by the altimeters is arguably one of the most sensitive indicators of climate change because it varies almost entirely due to thermal expansion/contraction and the exchange of water between the land and oceans. Contributions to the latter include melting land ice and changes in the hydrologic cycle. While thermal expansion does not vary greatly on interannual time-scales, variations in the global hydrologic cycle and land ice melt can contribute to large variations in the sea level record. Isolating and understanding the causes and scales of these variations is important in interpreting the observed global and regional sea level change, especially for decision-makers assessing risk and planning for adaptation and/or mitigation. Since 1992, satellite altimeter measurements from the TOPEX/Poseidon and Jason missions, have been providing precise estimates of sea level change between ±66° latitude every 10 days. We have been using these measurements to monitor both global average and regional sea level change. The GRACE mission has provided monthly estimates of the time-varying gravity field for the last 10 years. These measurements can estimate variations in global ocean mass, mass changes in the polar ice sheets and mountain glaciers, as well as changes in the land surface water storage. These data sets can be used to inform us about the sea level change

  14. Sea-Level Rise Impacts on Hudson River Marshes

    NASA Astrophysics Data System (ADS)

    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.

  15. 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

    DTIC Science & Technology

    2016-04-01

    SERDP NOAA USACE Ocean MANAGING THE UNCERTAINTY OF FUTURE SEA LEVEL CHANGE AND EXTREME WATER LEVELS FOR DEPARTMENT OF DEFENSE COASTAL SITES...Uncertainty of Future Sea Level Change and Extreme Water Levels for Department of Defense Coastal Sites Worldwide. U.S. Department of Defense...Strategic Environmental Research and Development Program. 224 pp. MANAGING THE UNCERTAINTY OF FUTURE SEA LEVEL CHANGE AND EXTREME WATER LEVELS FOR

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

    NASA Astrophysics Data System (ADS)

    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 (<2 h) may substantially contribute to global 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.

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

    PubMed Central

    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 (<2 h) may substantially contribute to global 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. PMID:28098195

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

    PubMed

    Vilibić, Ivica; Šepić, Jadranka

    2017-01-18

    Present investigations of sea level extremes are based on hourly data measured at coastal tide gauges. The use of hourly data restricts existing global and regional analyses to periods larger than 2 h. However, a number of processes occur at minute timescales, of which the most ruinous are tsunamis. Meteotsunamis, hazardous nonseismic waves that occur at tsunami timescales over limited regions, may also locally dominate sea level extremes. Here, we show that nonseismic sea level oscillations at tsunami timescales (<2 h) may substantially contribute to global 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.

  19. Eastern tropical Pacific vegetation response to rapid climate change and sea level rise: A new pollen record from the Gulf of Tehuantepec, southern Mexico

    NASA Astrophysics Data System (ADS)

    Hendy, I. L.; Minckley, T. A.; Whitlock, C.

    2016-08-01

    A 30,000-year-long pollen record from the Gulf of Tehuantepec, southern Mexico shows the varying influence of air temperature, precipitation and eustatic sea-level rise on changes in coastal and upland vegetation patterns. During the late-glacial period, pine-juniper forests grew in the Sierra Madre del Sur along the Pacific Slope with broadleaf forests present at low elevations. Coastal wetland and riparian vegetation were limited in distribution. Significant cooling associated with Heinrich 1 (17,000-15,000 cal yr BP) resulted in an expansion of pine-juniper woodland. By the time of Bølling-Allerød warming (14,700-13,000 cal yr BP), extensive mangrove forest development was assisted by sea-level rise and reduced precipitation associated with a more southerly position of the Intertropical Convergence Zone (ITCZ) than at present. Concurrently, the expansion of oak into pine woodlands was promoted by warmer conditions than before. Increased summer precipitation in the early Holocene and stabilizing sea levels limited mangrove forests along the coast and allowed mixed conifer and hardwood forest to become more widespread inland. The onset of a more seasonal climate, driven by a weakening of the Mexican monsoon and a southerly shift in ITCZ position led to the establishment of modern open forests of pine and oak after 4300 cal yr BP.

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

    NASA Astrophysics Data System (ADS)

    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

  1. The Phanerozoic record of global sea-level change.

    PubMed

    Miller, Kenneth G; Kominz, Michelle A; Browning, James V; Wright, James D; Mountain, Gregory S; Katz, Miriam E; Sugarman, Peter J; Cramer, Benjamin S; Christie-Blick, Nicholas; Pekar, Stephen F

    2005-11-25

    We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 +/- 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 10(4)- to 10(6)-year scale, but a link between oxygen isotope and sea level on the 10(7)-year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).

  2. On the relationship between sea level and Spartina alterniflora production

    USGS Publications Warehouse

    Kirwan, Matthew L.; Christian, Robert R.; Blum, Linda K.; Brinson, Mark M.

    2012-01-01

    A positive relationship between interannual sea level and plant growth is thought to stabilize many coastal landforms responding to accelerating rates of sea level rise. Numerical models of delta growth, tidal channel network evolution, and ecosystem resilience incorporate a hump-shaped relationship between inundation and plant primary production, where vegetation growth increases with sea level up to an optimum water depth or inundation frequency. In contrast, we use decade-long measurements of Spartina alterniflora biomass in seven coastal Virginia (USA) marshes to demonstrate that interannual sea level is rarely a primary determinant of vegetation growth. Although we find tepid support for a hump-shaped relationship between aboveground production and inundation when marshes of different elevation are considered, our results suggest that marshes high in the intertidal zone and low in relief are unresponsive to sea level fluctuations. We suggest existing models are unable to capture the behavior of wetlands in these portions of the landscape, and may underestimate their vulnerability to sea level rise because sea level rise will not be accompanied by enhanced plant growth and resultant sediment accumulation.

  3. Sea level change: lessons from the geologic record

    USGS Publications Warehouse

    ,

    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.

  4. Upper Limit for Sea Level Projections by 2100

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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.

  5. Upper Limit for Sea Level Projections by 2100

    NASA Astrophysics Data System (ADS)

    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.

  6. Impact of global seismicity on sea level change assessment

    NASA Astrophysics Data System (ADS)

    Melini, D.; Piersanti, A.

    2006-03-01

    We analyze the effect of seismic activity on sea level variations by computing the time-dependent vertical crustal movement and geoid change due to coseismic deformations and postseismic relaxation effects. Seismic activity can affect both the absolute sea level, changing the Earth's gravity field and hence the geoid height, and the relative sea level (RSL), i.e., the radial distance between seafloor and geoid level. By using comprehensive seismic catalogs we assess the net effect of seismicity on tidal relative sea level measurements as well as on the global oceanic surfaces, and we obtain an estimate of absolute sea level variations of seismic origin. We modified the approach adopted in our previous analysis, considering the issue of water volume conservation by applying the sealevel equation, and we improved our computational methods, enabling us to evaluate the effect of an extremely large number of earthquakes on large grids covering the whole oceanic surface. These new potentialities allow us to perform more detailed investigations and to discover a quantitative explanation for the overall tendency of earthquakes to produce a positive global relative sea level variation. Our results confirm the finding of a previous analysis that on a global scale most of the signal is associated with a few giant thrust events and that RSL estimates obtained using tide gauge data can be sensibly affected by the seismically driven sea level signal. The recent measures of sea level obtained by satellite altimetry show a wide regional variation of sea level trends over the oceanic surface, with the largest deviations from the mean trend occurring in tectonically active regions. While our estimates of average absolute sea level variations turn out to be orders of magnitude smaller than the satellite-measured variations, we can still argue that the mass redistribution associated with aseismic tectonic processes may contribute to the observed regional variability of sea level

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  8. Subsidence and Relative Sea-level Rise in Threatened Deltas

    NASA Astrophysics Data System (ADS)

    Syvitski, J. P.; Higgins, S.

    2014-12-01

    In determining the risk lowland deltaic topography, as threatened by sea level rise and land subsidence, a number of important processes must be evaluated. Sea level rise is a global process but with local manifestations. Asian deltas have been experiencing higher rates of sea level rise due to the steric impact on dynamic (ocean) topography. Other large scale geophysical impacts on relative sea level at the local scale include the isostatic and flexural response to Holocene sea level history, Holocene sediment loads, and in former ice sheet zones --- glacial rebound. Tectonism does play a role on relative sea level rise, particularly in South America where the Eastern coastline, particularly Argentina, is rising relative to regional sea levels. Subsidence is impacted by both natural ground compaction, and accelerated compaction due to, for example, peat oxidation that often has a human driver (e.g. swamp reclammation). Subsidence is also impacted by the extraction of deeper deposits of petroleum and water. Rates of delta subsidence vary widely, depending on the magnitude of the anthropogenic driver, from a few mm/y to 100's of mm/y. Ground water withdrawal is the dominant reason behind much of the world's coastal subsidence, with important exceptions. On average subsidence rates (all causes) now contribute to local sea level innundations at rates four times faster then sea level is rising. New technologies, particularly InSAR and GPS methods, can often pin point the local cause (e.g. water withdrawl for agriculture versus for aquaculture). Subsurface soil or rock heterogeneity, and other very local geological patterns such as historical river pathways, also influence the temporal and spatial patterns associated with delta subsidence.

  9. Evolution of a Greenland Ice sheet Including Shelves and Regional Sea Level Variations

    NASA Astrophysics Data System (ADS)

    Bradley, S.; Reerink, T.; Vandewal, R.; Helsen, M.

    2015-12-01

    Observational evidence, including offshore moraines and marine sediment cores infer that at the Last Glacial maximum (LGM) the Greenland ice sheet (GIS) grounded out across the Davis Strait into Baffin Bay, with fast flowing ice streams extending out to the continental shelf break along the NW margin. These observations lead to a number of questions as to weather the GIS and Laurentide ice sheet (LIS) coalesced during glacial maximums, and if so, did a significant ice shelf develop across Baffin Bay and how would such a configuration impact on the relative contribution of these ice sheets to eustatic sea level (ESL). Most previous paleo ice sheet modelling simulations of the GIS recreated an ice sheet that either did not extend out onto the continental shelf or utilised a simplified marine ice parameterisation to recreate an extended GIS, and therefore did not fully include ice shelf dynamics. In this study we simulate the evolution of the GIS from 220 kyr BP to present day using IMAU-ice; a 3D thermodynamical ice sheet model which fully accounts for grounded and floating ice, calculates grounding line migration and ice shelf dynamics. There is few observational estimates of long-term (yrs) sub marine basal melting rates (mbm) for the GIS. Therefore we investigate a range of relationships to constrain the spatial and temporal parameterisation of mbm within IMAU-ice related to changes in paleo water depth, driven by changes in relative sea level and ocean temperature. We will present results of how changes in the mbm directly impacts on the ice sheet dynamics, timing and spatial extent of the GIS at the glacial maximums, but also on the rate of retreat and spatial extent at the Last interglacial (LIG) minimum. Initial results indicate that with the inclusion of ice shelf dynamics, a larger GIS is generated which is grounded out into Davis strait, up to a water depth of -750 m, but the total contribution to LIG ESL is reduced by up to 0.6 m.

  10. Evolution of a Greenland Ice sheet Including Shelves and Regional Sea Level Variations

    NASA Astrophysics Data System (ADS)

    Bradley, Sarah; Reerink, Thomas; van de Wal, Roderik S. W.; Helsen, Michiel; Goelzer, Heiko

    2016-04-01

    Observational evidence, including offshore moraines and marine sediment cores infer that at the Last Glacial maximum (LGM) the Greenland ice sheet (GIS) grounded out across the Davis Strait into Baffin Bay, with fast flowing ice streams extending out to the continental shelf break along the NW margin. These observations lead to a number of questions as to weather the GIS and Laurentide ice sheet (LIS) coalesced during glacial maximums, and if so, did a significant ice shelf develop across Baffin Bay and how would such a configuration impact on the relative contribution of these ice sheets to eustatic sea level (ESL). Most previous paleo ice sheet modelling simulations of the GIS recreated an ice sheet that either did not extend out onto the continental shelf or utilised a simplified marine ice parameterisation to recreate an extended GIS, and therefore did not fully include ice shelf dynamics. In this study we simulate the evolution of the GIS from 220 kyr BP to present day using IMAU-ice; a 3D thermodynamical ice sheet model which fully accounts for grounded and floating ice, calculates grounding line migration and ice shelf dynamics. As there are few observational estimates of the long-term (yrs) sub marine basal melting rates (mbm) for the GIS, we developed a mbm parameterization within IMAU-ice controlled primarily by changes in paleo water depth. We also investigate the influence of the LIS on the GIS evolution by including relative sea level forcing's derived from a Glacial Isostatic Adjustment model. We will present results of how changes in the mbm directly impacts on the ice sheet dynamics, timing and spatial extent of the GIS at the glacial maximums, but also on the rate of retreat and spatial extent at the Last interglacial (LIG) minimum. Results indicate that with the inclusion of ice shelf dynamics, a larger GIS is generated which is grounded out into Davis strait, up to a water depth of -750 m, but significantly reduces the GIS contribution to Last

  11. Sea level trend and variability around Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  12. An alternative to reduction of surface pressure to sea level

    NASA Technical Reports Server (NTRS)

    Deardorff, J. W.

    1982-01-01

    The pitfalls of the present method of reducing surface pressure to sea level are reviewed, and an alternative, adjusted pressure, P, is proposed. P is obtained from solution of a Poisson equation over a continental region, using the simplest boundary condition along the perimeter or coastline where P equals the sea level pressure. The use of P would avoid the empiricisms and disadvantages of pressure reduction to sea level, and would produce surface pressure charts which depict the true geostrophic wind at the surface.

  13. Coastal Impact Underestimated From Rapid Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Anderson, John; Milliken, Kristy; Wallace, Davin; Rodriguez, Antonio; Simms, Alexander

    2010-06-01

    A primary effect of global warming is accelerated sea level rise, which will eventually drown low-lying coastal areas, including some of the world's most populated cities. Predictions from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) suggest that sea level may rise by as much as 0.6 meter by 2100 [Solomon et al., 2007]. However, uncertainty remains about how projected melting of the Greenland and Antarctic ice sheets will contribute to sea level rise. Further, considerable variability is introduced to these calculations due to coastal subsidence, especially along the northern Gulf of Mexico (see http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml).

  14. Explaining trends and variability in coastal relative sea level

    NASA Astrophysics Data System (ADS)

    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.

  15. Sea-level variability over five glacial cycles.

    PubMed

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

    2014-09-25

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

  16. Sea water intrusion by sea-level rise: scenarios for the 21st century.

    PubMed

    Loáiciga, Hugo A; Pingel, Thomas J; Garcia, Elizabeth S

    2012-01-01

    This study presents a method to assess the contributions of 21st-century sea-level rise and groundwater extraction to sea water intrusion in coastal aquifers. Sea water intrusion is represented by the landward advance of the 10,000 mg/L iso-salinity line, a concentration of dissolved salts that renders groundwater unsuitable for human use. A mathematical formulation of the resolution of sea water intrusion among its causes was quantified via numerical simulation under scenarios of change in groundwater extraction and sea-level rise in the 21st century. The developed method is illustrated with simulations of sea water intrusion in the Seaside Area sub-basin near the City of Monterey, California (USA), where predictions of mean sea-level rise through the early 21st century range from 0.10 to 0.90 m due to increasing global mean surface temperature. The modeling simulation was carried out with a state-of-the-art numerical model that accounts for the effects of salinity on groundwater density and can approximate hydrostratigraphic geometry closely. Simulations of sea water intrusion corresponding to various combinations of groundwater extraction and sea-level rise established that groundwater extraction is the predominant driver of sea water intrusion in the study aquifer. The method presented in this work is applicable to coastal aquifers under a variety of other scenarios of change not considered in this work. For example, one could resolve what changes in groundwater extraction and/or sea level would cause specified levels of groundwater salinization at strategic locations and times.

  17. Late Holocene sea level changes and tectonic movements inferred from fossil diatom assemblages in Tainohama, Tokushima prefecture, Japan

    NASA Astrophysics Data System (ADS)

    Chiba, T.; Fujino, S.; Kobori, E.

    2014-12-01

    freshwater species, suggesting paleo-sea level changes. The sea level in this area declined gradually to modern sea level from +50cm higher level than modern by eustatic sea level fall during the late Holocene (Sato 2014), thus the fluctuations suggest co-seismic or inter-seismic crustal movements of the past interplate earthquakes along the Nankai Trough.

  18. The influence of high viscosity slabs on post-glacial sea-level change: the case of Barbados

    NASA Astrophysics Data System (ADS)

    Austermann, Jacqueline; Mitrovica, Jerry X.; Latychev, Konstantin

    2013-04-01

    The coral record at Barbados is one of the best available measures of relative sea level during the last glacial cycle and has been widely used to reconstruct ice volume (or, equivalently, eustatic sea-level, ESL) changes during the last deglaciation phase of the ice age. However, to estimate ESL variations from the local relative sea level (RSL) history at Barbados, one has to account for the contaminating effect of glacial isostatic adjustment (GIA). In previous work, the GIA signal at this site has been corrected for by assuming a spherically symmetric (i.e., 1-D) viscoelastic Earth. Since Barbados is located at the margin of the South American - Caribbean subduction zone, this assumption may introduce a significant error in inferences of ice volumes. To address this issue, we use a finite-volume numerical code to model GIA in the Caribbean region including the effects of a lithosphere with variable elastic thickness, plate boundaries, lateral variations in lower mantle viscosity, and a high viscosity slab within the upper mantle. The geometry of the subducted slab is inferred from local seismicity. We find that predictions of relative sea-level change since the Last Glacial Maximum (LGM) in the Caribbean region are diminished by ~10 m, relative to 1-D calculations, which suggests that previous studies have underestimated post-LGM ESL change by the same amount. This perturbation, which largely reflects the impact of the high viscosity slab, is nearly twice the total GIA-induced departure from eustasy predicted at Barbados using the 1-D Earth model. Our calculations imply an excess ice-volume equivalent to ~130 m ESL at the LGM, which brings the Barbados-based estimate into agreement with inferences based on other far-field RSL histories, such as at Bonaparte Gulf. This inference, together with recent studies that have substantially lowered estimates of Antarctic Ice Sheet mass at LGM, suggest that a significant amount of ice remains unaccounted for in sea-level

  19. Developing a Coastal Risk Indicator for Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Masters, D. S.; Nerem, R.

    2012-12-01

    Coastal sea level rise is one the most important potential environmental risks. Multiple satellite altimeters flying on the same repeat orbit track have allowed estimation of global mean sea level for the past 20 years, and the time series has yielded information about the average rate of sea level increase over that time. Due to the duration, consistency, and inter-calibration of the altimeter measurements, the time series is now considered a climate record. The time series has also shown the strong dependence of sea level on interannual signals such as the ENSO and the NAO. But the most important sea level effects of climate change will be felt on the regional and local scales. At these smaller scales, local effects due to topography, tides, earth deformation (glacial isostatic adjustment (GIA), subsidence, etc.), and storm surges must also be considered when estimating the risks of sea level change to coastal communities. Recently, work has begun to understand the methods applicable to estimating the risks of expected sea level change to coastal communities (Strauss et al., 2012; Tebaldi et al., 2012). Tebaldi et al (2012) merged the expected global mean sea level increase from the semi-empirical model of Vermeer and Rahmstorf (2009) with historical local tide gauges to predict increases in storm surge risk posed by increasing sea level. In this work, we will further explore the currently available data and tools that can potentially be used to provide a sea level climate change indicator and local risk assessment along US coasts. These include global and regional sea level trends from the satellite altimetry climate record, in situ tide gauge measurements and the historical extremes at each location, local tide and storm surge models, topographic surveys of vulnerable coastlines, GIA models, and measurements of local subsidence and crustal deformation rates. We will also evaluate methods to estimate the increased risk to communities from sea level change

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  2. Hazard Risk to Near Sea-Level Populations due to Tropical Cyclone Intensification and Sea-Level Rise

    NASA Astrophysics Data System (ADS)

    Montain, J.; Byrne, J. M.; Elsner, J.

    2010-12-01

    Tropical cyclone (TC) intensification has been well documented in the science literature. TC intensification combined with sea-level rise contributes to an enhanced risk to huge populations living near sea level around the world. This study will apply spatial analysis techniques to combine the best available TC intensification data on storm surge, wave height and wind speeds; with digital elevation models and global population density estimates, to provide a first level evaluation of the increasing risk to human life and health.

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

    NASA Astrophysics Data System (ADS)

    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

  4. The anatomy of recent large sea level fluctuations in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Landerer, Felix W.; Volkov, Denis L.

    2013-02-01

    Abstract During the boreal winter months of 2009/2010 and 2010/2011, Mediterranean mean <span class="hlt">sea</span> <span class="hlt">level</span> rose 10 cm above the average monthly climatological values. The non-seasonal anomalies were observed in <span class="hlt">sea</span> surface height (from altimetry), as well as ocean mass (from gravimetry), indicating they were mostly of barotropic nature. These relatively rapid basin-wide fluctuations occurred over time scales of 1-5 months. Here we use observations and re-analysis data to attribute the non-seasonal <span class="hlt">sea</span> <span class="hlt">level</span> and ocean mass fluctuations in the Mediterranean <span class="hlt">Sea</span> to concurrent wind stress anomalies over the adjacent subtropical Northeast Atlantic Ocean, just west of the Strait of Gibraltar, and extending into the strait itself. The observed Mediterranean <span class="hlt">sea</span> <span class="hlt">level</span> fluctuations are strongly anti-correlated with the monthly North-Atlantic-Oscillation (NAO) index.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1710077E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1710077E"><span id="translatedtitle">Characterization of extreme <span class="hlt">sea</span> <span class="hlt">level</span> at the European coast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elizalde, Alberto; Jorda, Gabriel; Mathis, Moritz; Mikolajewicz, Uwe</p> <p>2015-04-01</p> <p>Extreme high <span class="hlt">sea</span> <span class="hlt">levels</span> arise as a combination of storm surges and particular high tides events. Future climate simulations not only project changes in the atmospheric circulation, which induces changes in the wind conditions, but also an increase in the global mean <span class="hlt">sea</span> <span class="hlt">level</span> by thermal expansion and ice melting. Such changes increase the risk of coastal flooding, which represents a possible hazard for human activities. Therefore, it is important to investigate the pattern of <span class="hlt">sea</span> <span class="hlt">level</span> variability and long-term trends at coastal areas. In order to analyze further extreme <span class="hlt">sea</span> <span class="hlt">level</span> events at the European coast in the future climate projections, a new setup for the global ocean model MPIOM coupled with the regional atmosphere model REMO is prepared. The MPIOM irregular grid has enhanced resolution in the European region to resolve the North and the Mediterranean <span class="hlt">Seas</span> (up to 11 x 11 km at the North <span class="hlt">Sea</span>). The ocean model includes as well the full luni-solar ephemeridic tidal potential for tides simulation. To simulate the air-<span class="hlt">sea</span> interaction, the regional atmospheric model REMO is interactively coupled to the ocean model over Europe. Such region corresponds to the EuroCORDEX domain with a 50 x 50 km resolution. Besides the standard fluxes of heat, mass (freshwater), momentum and turbulent energy input, the ocean model is also forced with <span class="hlt">sea</span> <span class="hlt">level</span> pressure, in order to be able to capture the full variation of <span class="hlt">sea</span> <span class="hlt">level</span>. The hydrological budget within the study domain is closed using a hydrological discharge model. With this model, simulations for present climate and future climate scenarios are carried out to study transient changes on the <span class="hlt">sea</span> <span class="hlt">level</span> and extreme events. As a first step, two simulations (coupled and uncoupled ocean) driven by reanalysis data (ERA40) have been conducted. They are used as reference runs to evaluate the climate projection simulations. For selected locations at the coast side, time series of <span class="hlt">sea</span> <span class="hlt">level</span> are separated on its different</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatCo...711969M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatCo...711969M"><span id="translatedtitle">A global reanalysis of storm surges and extreme <span class="hlt">sea</span> <span class="hlt">levels</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muis, Sanne; Verlaan, Martin; Winsemius, Hessel C.; Aerts, Jeroen C. J. H.; Ward, Philip J.</p> <p>2016-06-01</p> <p>Extreme <span class="hlt">sea</span> <span class="hlt">levels</span>, caused by storm surges and high tides, can have devastating societal impacts. To effectively protect our coasts, global information on coastal flooding is needed. Here we present the first global reanalysis of storm surges and extreme <span class="hlt">sea</span> <span class="hlt">levels</span> (GTSR data set) based on hydrodynamic modelling. GTSR covers the entire world's coastline and consists of time series of tides and surges, and estimates of extreme <span class="hlt">sea</span> <span class="hlt">levels</span>. Validation shows that there is good agreement between modelled and observed <span class="hlt">sea</span> <span class="hlt">levels</span>, and that the performance of GTSR is similar to that of many regional hydrodynamic models. Due to the limited resolution of the meteorological forcing, extremes are slightly underestimated. This particularly affects tropical cyclones, which requires further research. We foresee applications in assessing flood risk and impacts of climate change. As a first application of GTSR, we estimate that 1.3% of the global population is exposed to a 1 in 100-year flood.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4931224','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4931224"><span id="translatedtitle">A global reanalysis of storm surges and extreme <span class="hlt">sea</span> <span class="hlt">levels</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Muis, Sanne; Verlaan, Martin; Winsemius, Hessel C.; Aerts, Jeroen C. J. H.; Ward, Philip J.</p> <p>2016-01-01</p> <p>Extreme <span class="hlt">sea</span> <span class="hlt">levels</span>, caused by storm surges and high tides, can have devastating societal impacts. To effectively protect our coasts, global information on coastal flooding is needed. Here we present the first global reanalysis of storm surges and extreme <span class="hlt">sea</span> <span class="hlt">levels</span> (GTSR data set) based on hydrodynamic modelling. GTSR covers the entire world's coastline and consists of time series of tides and surges, and estimates of extreme <span class="hlt">sea</span> <span class="hlt">levels</span>. Validation shows that there is good agreement between modelled and observed <span class="hlt">sea</span> <span class="hlt">levels</span>, and that the performance of GTSR is similar to that of many regional hydrodynamic models. Due to the limited resolution of the meteorological forcing, extremes are slightly underestimated. This particularly affects tropical cyclones, which requires further research. We foresee applications in assessing flood risk and impacts of climate change. As a first application of GTSR, we estimate that 1.3% of the global population is exposed to a 1 in 100-year flood. PMID:27346549</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatCC...6..253K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatCC...6..253K"><span id="translatedtitle">Overestimation of marsh vulnerability to <span class="hlt">sea</span> <span class="hlt">level</span> rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirwan, Matthew L.; Temmerman, Stijn; Skeehan, Emily E.; Guntenspergen, Glenn R.; Fagherazzi, Sergio</p> <p>2016-03-01</p> <p>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 <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> rise, and that process-based models predict survival under a wide range of future <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> rise, and the potential for marshes to migrate inland.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Natur.532...42F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Natur.532...42F"><span id="translatedtitle">Island biogeography: Shaped by <span class="hlt">sea-level</span> shifts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández-Palacios, José María</p> <p>2016-04-01</p> <p>An analysis of changes in island topography and climate that have occurred since the last glacial maximum 21,000 years ago shows how <span class="hlt">sea-level</span> change has influenced the current biodiversity of oceanic islands. See Letter p.99</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.6747M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.6747M"><span id="translatedtitle">Seasonal coastal <span class="hlt">sea</span> <span class="hlt">level</span> prediction using a dynamical model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McIntosh, Peter C.; Church, John A.; Miles, Elaine R.; Ridgway, Ken; Spillman, Claire M.</p> <p>2015-08-01</p> <p><span class="hlt">Sea</span> <span class="hlt">level</span> varies on a range of time scales from tidal to decadal and centennial change. To date, little attention has been focussed on the prediction of interannual <span class="hlt">sea</span> <span class="hlt">level</span> anomalies. Here we demonstrate that forecasts of coastal <span class="hlt">sea</span> <span class="hlt">level</span> anomalies from the dynamical Predictive Ocean Atmosphere Model for Australia (POAMA) have significant skill throughout the equatorial Pacific and along the eastern boundaries of the Pacific and Indian Oceans at lead times out to 8 months. POAMA forecasts for the western Pacific generally have greater skill than persistence, particularly at longer lead times. POAMA also has comparable or greater skill than previously published statistical forecasts from both a Markov model and canonical correlation analysis. Our results indicate the capability of physically based models to address the challenge of providing skillful forecasts of seasonal <span class="hlt">sea</span> <span class="hlt">level</span> fluctuations for coastal communities over a broad area and at a range of lead times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=7l7BY2B3jSU','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=7l7BY2B3jSU"><span id="translatedtitle">Twenty-two Years of <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise</span></a></p> <p><a target="_blank" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p></p> <p></p> <p>This visualization shows total <span class="hlt">sea</span> <span class="hlt">level</span> change between the beginning of 1993 and the end of 2014, based on data collected from the TOPEX/Poisedon, Jason-1, and Jason-2 satellites. Blue regions are...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70169064','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70169064"><span id="translatedtitle">Overestimation of marsh vulnerability to <span class="hlt">sea</span> <span class="hlt">level</span> rise</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kirwan, Matthew L.; Temmerman, Stijn; Skeehan, Emily E.; Guntenspergen, Glenn R.; Fagherazzi, Sergio</p> <p>2016-01-01</p> <p>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 <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> rise, and that process-based models predict survival under a wide range of future <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> rise, and the potential for marshes to migrate inland.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6784832','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6784832"><span id="translatedtitle">Chronology of fluctuating <span class="hlt">sea</span> <span class="hlt">levels</span> since the triassic</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Haq, B.U.; Hardenbol, J.; Vail, P.R.</p> <p>1987-03-06</p> <p>Advances in sequence stratigraphy and the development of depositional models have helped explain the origin of genetically related sedimentary packages during <span class="hlt">sea</span> <span class="hlt">level</span> cycles. These concepts have provided the basis for the recognition of <span class="hlt">sea</span> <span class="hlt">level</span> events in subsurface data and in outcrops of marine sediments around the world. Knowledge of these events has led to a new generation of Mesozoic and Cenozoic global cycle charts that chronicle the history of <span class="hlt">sea</span> <span class="hlt">level</span> fluctuations during the past 250 million years in greater detail than was possible from seismic-stratigraphic data alone. An effort has been made to develop a realistic and accurate time scale and widely applicable chronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework. A description of this approach and an account of the results, illustrated by <span class="hlt">sea</span> <span class="hlt">level</span> cycle charts of the Cenozoic, Cretaceous, Jurassic, and Triassic intervals, are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70121272','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70121272"><span id="translatedtitle">[Book review] <span class="hlt">Sea</span> <span class="hlt">level</span> rise: history and consequences</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Grossman, Eric E.</p> <p>2004-01-01</p> <p>Review of: <span class="hlt">Sea</span> <span class="hlt">level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26160951','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26160951"><span id="translatedtitle"><span class="hlt">SEA-LEVEL</span> RISE. <span class="hlt">Sea-level</span> rise due to polar ice-sheet mass loss during past warm periods.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dutton, A; Carlson, A E; Long, A J; Milne, G A; Clark, P U; DeConto, R; Horton, B P; Rahmstorf, S; Raymo, M E</p> <p>2015-07-10</p> <p>Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of <span class="hlt">sea-level</span> rise from polar ice-sheet loss during past warm periods. Accounting for glacial isostatic processes helps to reconcile spatial variability in peak <span class="hlt">sea</span> <span class="hlt">level</span> during marine isotope stages 5e and 11, when the global mean reached 6 to 9 meters and 6 to 13 meters higher than present, respectively. Dynamic topography introduces large uncertainties on longer time scales, precluding robust <span class="hlt">sea-level</span> estimates for intervals such as the Pliocene. Present climate is warming to a <span class="hlt">level</span> associated with significant polar ice-sheet loss in the past. Here, we outline advances and challenges involved in constraining ice-sheet sensitivity to climate change with use of paleo-<span class="hlt">sea</span> <span class="hlt">level</span> records.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870033250&hterms=sea+level+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsea%2Blevel%2Bchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870033250&hterms=sea+level+change&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsea%2Blevel%2Bchange"><span id="translatedtitle">Accurate measurement of mean <span class="hlt">sea</span> <span class="hlt">level</span> changes by altimetric satellites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Born, G. H.; Tapley, B. D.; Ries, J. C.; Stewart, R. H.</p> <p>1986-01-01</p> <p>A technique for monitoring changes in global mean <span class="hlt">sea</span> <span class="hlt">levels</span> using altimeter data from a well-tracked satellite is examined. The usefulness of this technique is evaluated by analyzing Seasat altimeter data obtained during July-September 1978. The effects of orbit errors, geoid errors, sampling intervals, tides, and atmosphere refraction on the calculation of the mean <span class="hlt">sea</span> <span class="hlt">level</span> are investigated. The data reveal that the stability of an altimeter can be determined with an accuracy of + or - 7 cm using globally averaged <span class="hlt">sea</span> surface height measurements. The application of this procedure to the US/French Ocean Topography Experiment is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920037309&hterms=Sargasso+Sea&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DSargasso%2BSea','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920037309&hterms=Sargasso+Sea&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DSargasso%2BSea"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> differences across the Gulf Stream and Kuroshio extension</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zlotnicki, Victor</p> <p>1991-01-01</p> <p>The <span class="hlt">sea</span> <span class="hlt">level</span> differences between the Sargasso <span class="hlt">Sea</span> 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 <span class="hlt">sea-level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11679657','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11679657"><span id="translatedtitle">Climate change. How fast are <span class="hlt">sea</span> <span class="hlt">levels</span> rising?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Church, J A</p> <p>2001-10-26</p> <p><span class="hlt">Sea</span> <span class="hlt">levels</span> are rising as a result of global warming, but assessing the rate of the rise is proving difficult. In his Perspective, Church highlights the report by Cabanes et al., who have reassessed observational data and find that it is closer to model estimates than previously found. However, observational data are still limited and models disagree in their regional projections. With present data and models, regional <span class="hlt">sea-level</span> changes cannot be predicted with confidence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AIPC.1157...19P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AIPC.1157...19P"><span id="translatedtitle">Adapting to Rising <span class="hlt">Sea</span> <span class="hlt">Level</span>: A Florida Perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parkinson, Randall W.</p> <p>2009-07-01</p> <p>Global climate change and concomitant rising <span class="hlt">sea</span> <span class="hlt">level</span> will have a profound impact on Florida's coastal and marine systems. <span class="hlt">Sea-level</span> rise will increase erosion of beaches, cause saltwater intrusion into water supplies, inundate coastal marshes and other important habitats, and make coastal property more vulnerable to erosion and flooding. Yet most coastal areas are currently managed under the premise that <span class="hlt">sea-level</span> rise is not significant and the shorelines are static or can be fixed in place by engineering structures. The new reality of <span class="hlt">sea-level</span> rise and extreme weather due to climate change requires a new style of planning and management to protect resources and reduce risk to humans. Scientists must: (1) assess existing coastal vulnerability to address short term management issues and (2) model future landscape change and develop sustainable plans to address long term planning and management issues. Furthermore, this information must be effectively transferred to planners, managers, and elected officials to ensure their decisions are based upon the best available information. While there is still some uncertainty regarding the details of rising <span class="hlt">sea</span> <span class="hlt">level</span> and climate change, development decisions are being made today which commit public and private investment in real estate and associated infrastructure. With a design life of 30 yrs to 75 yrs or more, many of these investments are on a collision course with rising <span class="hlt">sea</span> <span class="hlt">level</span> and the resulting impacts will be significant. In the near term, the utilization of engineering structures may be required, but these are not sustainable and must ultimately yield to "managed withdrawal" programs if higher <span class="hlt">sea-level</span> elevations or rates of rise are forthcoming. As an initial step towards successful adaptation, coastal management and planning documents (i.e., comprehensive plans) must be revised to include reference to climate change and rising <span class="hlt">sea-level</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020486','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020486"><span id="translatedtitle">Cenozoic global <span class="hlt">sea</span> <span class="hlt">level</span>, sequences, and the New Jersey transect: Results from coastal plain and continental slope drilling</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Miller, K.G.; Mountain, Gregory S.; Browning, J.V.; Kominz, M.; Sugarman, P.J.; Christie-Blick, N.; Katz, M.E.; Wright, J.D.</p> <p>1998-01-01</p> <p>The New Jersey <span class="hlt">Sea</span> <span class="hlt">Level</span> Transect was designed to evaluate the relationships among global <span class="hlt">sea</span> <span class="hlt">level</span> (<span class="hlt">eustatic</span>) change, unconformity-bounded sequences, and variations in subsidence, sediment supply, and climate on a passive continental margin. By sampling and dating Cenozoic strata from coastal plain and continental slope locations, we show that sequence boundaries correlate (within ??0.5 myr) regionally (onshore-offshore) and interregionally (New Jersey-Alabama-Bahamas), implicating a global cause. Sequence boundaries correlate with ??18O increases for at least the past 42 myr, consistent with an ice volume (glacioeustatic) control, although a causal relationship is not required because of uncertainties in ages and correlations. Evidence for a causal connection is provided by preliminary Miocene data from slope Site 904 that directly link ??18O increases with sequence boundaries. We conclude that variation in the size of ice sheets has been a primary control on the formation of sequence boundaries since ~42 Ma. We speculate that prior to this, the growth and decay of small ice sheets caused small-amplitude <span class="hlt">sea</span> <span class="hlt">level</span> changes (<20 m) in this supposedly ice-free world because Eocene sequence boundaries also appear to correlate with minor ??18O increases. Subsidence estimates (backstripping) indicate amplitudes of short-term (million-year scale) lowerings that are consistent with estimates derived from ??18O studies (25-50 m in the Oligocene-middle Miocene and 10-20 m in the Eocene) and a long-term lowering of 150-200 m over the past 65 myr, consistent with estimates derived from volume changes on mid-ocean ridges. Although our results are consistent with the general number and timing of Paleocene to middle Miocene sequences published by workers at Exxon Production Research Company, our estimates of <span class="hlt">sea</span> <span class="hlt">level</span> amplitudes are substantially lower than theirs. Lithofacies patterns within sequences follow repetitive, predictable patterns: (1) coastal plain sequences consist</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010OcSci...6..311I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010OcSci...6..311I"><span id="translatedtitle">Seasonal variability of the Caspian <span class="hlt">Sea</span> three-dimensional circulation, <span class="hlt">sea</span> <span class="hlt">level</span> and air-<span class="hlt">sea</span> interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ibrayev, R. A.; Özsoy, E.; Schrum, C.; Sur, H. I.</p> <p>2010-03-01</p> <p>A three-dimensional primitive equation model including <span class="hlt">sea</span> ice thermodynamics and air-<span class="hlt">sea</span> interaction is used to study seasonal circulation and water mass variability in the Caspian <span class="hlt">Sea</span> 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 <span class="hlt">sea</span> surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated <span class="hlt">sea</span> surface temperature. The model successfully simulates <span class="hlt">sea-level</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> surface topography, yielding verifiable results in terms of <span class="hlt">sea</span> <span class="hlt">level</span>. The model successfully reproduces <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009OcScD...6.1913I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009OcScD...6.1913I"><span id="translatedtitle">Seasonal variability of the Caspian <span class="hlt">Sea</span> three-dimensional circulation, <span class="hlt">sea</span> <span class="hlt">level</span> and air-<span class="hlt">sea</span> interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ibrayev, R. A.; Özsoy, E.; Schrum, C.; Sur, H. İ.</p> <p>2009-09-01</p> <p>A three-dimensional primitive equation model including <span class="hlt">sea</span> ice thermodynamics and air-<span class="hlt">sea</span> interaction is used to study seasonal circulation and water mass variability in the Caspian <span class="hlt">Sea</span> 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 <span class="hlt">sea</span> surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated <span class="hlt">sea</span> surface temperature. The model successfully simulates <span class="hlt">sea-level</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> surface topography, yielding verifiable results in terms of <span class="hlt">sea</span> <span class="hlt">level</span>. Model successfully reproduces <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V53A3127H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V53A3127H"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> Variability and Juan de Fuca Bathymetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huybers, P. J.; Boulahanis, B.; Proistosescu, C.; Langmuir, C. H.; Carbotte, S. M.; Katz, R. F.</p> <p>2015-12-01</p> <p>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 <span class="hlt">sea</span> <span class="hlt">level</span> 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). <span class="hlt">Sea</span> <span class="hlt">level</span> 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 <span class="hlt">Sea</span>VOICE 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 <span class="hlt">sea</span> <span class="hlt">level</span> variability; (2.) whether <span class="hlt">sea</span> <span class="hlt">level</span> responses are primarily at 41 ky periods in crust accreted during the early Pleistocene, when global <span class="hlt">sea</span> <span class="hlt">level</span> variations were primarily at this period; and (3.) if <span class="hlt">sea</span> <span class="hlt">level</span> 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023308','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023308"><span id="translatedtitle">Experiments in Reconstructing Twentieth-Century <span class="hlt">Sea</span> <span class="hlt">Levels</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ray, Richard D.; Douglas, Bruce C.</p> <p>2011-01-01</p> <p>One approach to reconstructing historical <span class="hlt">sea</span> <span class="hlt">level</span> from the relatively sparse tide-gauge network is to employ Empirical Orthogonal Functions (EOFs) as interpolatory spatial basis functions. The EOFs are determined from independent global data, generally <span class="hlt">sea</span>-surface heights from either satellite altimetry or a numerical ocean model. The problem is revisited here for <span class="hlt">sea</span> <span class="hlt">level</span> since 1900. A new approach to handling the tide-gauge datum problem by direct solution offers possible advantages over the method of integrating <span class="hlt">sea-level</span> differences, with the potential of eventually adjusting datums into the global terrestrial reference frame. The resulting time series of global mean <span class="hlt">sea</span> <span class="hlt">levels</span> appears fairly insensitive to the adopted set of EOFs. In contrast, charts of regional <span class="hlt">sea</span> <span class="hlt">level</span> anomalies and trends are very sensitive to the adopted set of EOFs, especially for the sparser network of gauges in the early 20th century. The reconstructions appear especially suspect before 1950 in the tropical Pacific. While this limits some applications of the <span class="hlt">sea-level</span> reconstructions, the sensitivity does appear adequately captured by formal uncertainties. All our solutions show regional trends over the past five decades to be fairly uniform throughout the global ocean, in contrast to trends observed over the shorter altimeter era. Consistent with several previous estimates, the global <span class="hlt">sea-level</span> rise since 1900 is 1.70 +/- 0.26 mm/yr. The global trend since 1995 exceeds 3 mm/yr which is consistent with altimeter measurements, but this large trend was possibly also reached between 1935 and 1950.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20120010653&hterms=sea+level&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsea%2Blevel','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20120010653&hterms=sea+level&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsea%2Blevel"><span id="translatedtitle">Terrestrial Waters and <span class="hlt">Sea</span> <span class="hlt">Level</span> Variations on Interannual Time Scale</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Llovel, W.; Becker, M.; Cazenave, A.; Jevrejeva, S.; Alkama, R.; Decharme, B.; Douville, H.; Ablain, M.; Beckley, B.</p> <p>2011-01-01</p> <p>On decadal to multi-decadal time scales, thermal expansion of <span class="hlt">sea</span> waters and land ice loss are the main contributors to <span class="hlt">sea</span> <span class="hlt">level</span> variations. However, modification of the terrestrial water cycle due to climate variability and direct anthropogenic forcing may also affect <span class="hlt">sea</span> <span class="hlt">level</span>. For the past decades, variations in land water storage and corresponding effects on <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> equivalent) to observed mean <span class="hlt">sea</span> <span class="hlt">level</span>, 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 <span class="hlt">sea</span> <span class="hlt">level</span> is essentially explained by interannual fluctuations in land water storage, with the largest contributions arising from tropical river basins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMPP11E1471H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMPP11E1471H"><span id="translatedtitle">Identifying Glacio-<span class="hlt">Eustatic</span> Forcing of Unconformities In The Canterbury Basin (IODP Exp 317) Based on Oxygen Isotope Analysis Of The Fine Fraction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huck, C.; John, C. M.; Shevenell, A.; Shipboard Scientific Party, E.</p> <p>2010-12-01</p> <p>/kyr) and few hiatuses provide us with the best opportunity for a high-resolution δ18OFF record (0.1-0.5 my). The δ18OFF record indicates glacial intervals that we tie to the sequence stratigraphic record of the shelf. Constraining the amplitude of <span class="hlt">sea</span> <span class="hlt">level</span> change requires further paired analyses of the δ18O and Mg/Ca of well-preserved benthic foraminifers. Benthic foraminifers were visually assessed and only well preserved specimens were used in our pilot study. Our more accurate geochemical record of <span class="hlt">sea</span> <span class="hlt">level</span> change will be coupled with backstripping studies from other workers to offer insight into how the Canterbury Basin responded to <span class="hlt">eustatic</span>, paleoceanographic, and tectonic change during the Plio-Pleistocene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3871948','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3871948"><span id="translatedtitle">Impact of Altimeter Data Processing on <span class="hlt">Sea</span> <span class="hlt">Level</span> Studies</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fernandes, M. Joana; Barbosa, Susana; Lázaro, Clara</p> <p>2006-01-01</p> <p>This study addresses the impact of satellite altimetry data processing on <span class="hlt">sea</span> <span class="hlt">level</span> studies at regional scale, with emphasis on the influence of various geophysical corrections and satellite orbit on the structure of the derived interannual signal and <span class="hlt">sea</span> <span class="hlt">level</span> trend. The work focuses on the analysis of TOPEX data for a period of over twelve years, for three regions in the North Atlantic: Tropical (0°≤φ≤25°), Sub-Tropical (25°≤φ≤50°) and Sub-Arctic (50°≤φ≤65°). For this analysis corrected <span class="hlt">sea</span> <span class="hlt">level</span> anomalies with respect to a mean <span class="hlt">sea</span> surface model have been derived from the GDR-Ms provided by AVISO by applying various state-of-the-art models for the geophysical corrections. Results show that <span class="hlt">sea</span> <span class="hlt">level</span> trend determined from TOPEX altimetry is dependent on the adopted models for the major geophysical corrections. The main effects come from the <span class="hlt">sea</span> state bias (SSB), and from the application or not of the inverse barometer (IB) correction. After an appropriate modelling of the TOPEX A/B bias, the two analysed SSB models induce small variations in <span class="hlt">sea</span> <span class="hlt">level</span> trend, from 0.0 to 0.2 mm/yr, with a small latitude dependence. The difference in <span class="hlt">sea</span> <span class="hlt">level</span> trend determined by a non IB-corrected series and an IB-corrected one has a strong regional dependence with large differences in the shape of the interannual signals and in the derived linear 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 <span class="hlt">sea</span> <span class="hlt">level</span> trend of about 0.1 mm/yr. The interannual signals of <span class="hlt">sea</span> <span class="hlt">level</span> time series derived with the NASA and the CNES orbits respectively, show a small departure in the middle of the series, which has no impact on the derived <span class="hlt">sea</span> <span class="hlt">level</span> trend. These results strike the need for a continuous improvement in the modelling of the various effects that influence the altimeter measurement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMOS71D0325D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMOS71D0325D"><span id="translatedtitle">Extending the Instrumental Record of <span class="hlt">Sea-Level</span> Change: A 1300-Year <span class="hlt">Sea-Level</span> Record From Eastern Connecticut</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Donnelly, J. P.; Cleary, P.</p> <p>2002-12-01</p> <p>The instrumental record of <span class="hlt">sea-level</span> change in the northeastern United States extends back to the early 20th century and at New York City (NYC) extends back to 1856. These tide gauge records indicate that <span class="hlt">sea</span> <span class="hlt">level</span> has risen at a rate of 2.5 to 4 mm/year over the last 100-150 years. Geologic evidence of <span class="hlt">sea-level</span> change in the region over the last 2,000 years indicates rates of <span class="hlt">sea-level</span> rise of about 1 mm/year or less. The discordance between the instrumental and geologic records is frequently cited as potentially providing evidence that anthropogenic warming of the climate system has resulted in an increase in the rate of <span class="hlt">sea-level</span> rise. In order to begin to test the hypothesis that acceleration in the rate of <span class="hlt">sea-level</span> rise has occurred in the last 150 years due to anthropogenic climate warming, accurate and precise information on the timing of the apparent acceleration in <span class="hlt">sea-level</span> rise are needed. Here we construct a high-resolution relative <span class="hlt">sea-level</span> record for the past 1350 years by dating basal salt marsh peat samples above a glacial erratic in a western Connecticut salt marsh. Preservation of marsh vegetation remains in the sediment record that has a narrow vertical habitat range at the upper end of the tidal range provides information on past <span class="hlt">sea</span> <span class="hlt">levels</span>. { \\it Spartina patens} (marsh hay) and { \\it Juncus gerardi} (black rush) dominate both the modern marsh and their remains are the major constituent of the marsh sediments and occur in the modern marsh between mean high water (MHW) and mean highest high water. We use the elevation distribution of modern plant communities to estimate the relationship of sediment samples to paleo-mean high water. The chronology is based on 15 radiocarbon ages, supplemented by age estimates derived from the horizons of industrial Pb pollution and pollen indicative of European land clearance. Thirteen of the radiocarbon ages and the Pb and pollen data come from samples taken along a contact between marsh peat and a glacial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70175167','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70175167"><span id="translatedtitle">Continental Shelf Morphology and Stratigraphy Offshore San Onofre, CA: The Interplay Between Rates of <span class="hlt">Eustatic</span> Change and Sediment Supply</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Klotsko, Shannon; Driscoll, Neal W.; Kent, Graham; Brothers, Daniel</p> <p>2016-01-01</p> <p>New high-resolution CHIRP seismic data acquired offshore San Onofre, southern California reveal that shelf sediment distribution and thickness are primarily controlled by <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> rise and sediment supply. Throughout the majority of the study region, a prominent abrasion platform and associated shoreline cutoff are observed in the subsurface from ~ 72 to 53 m below present <span class="hlt">sea</span> <span class="hlt">level</span>. These erosional features appear to have formed between Melt Water Pulse 1A and Melt Water Pulse 1B, when the rate of <span class="hlt">sea-level</span> rise was lower. There are three distinct sedimentary units mapped above a regional angular unconformity interpreted to be the Holocene transgressive surface in the seismic data. Unit I, the deepest unit, is interpreted as a lag deposit that infills a topographic low associated with an abrasion platform. Unit I thins seaward by downlap and pinches out landward against the shoreline cutoff. Unit II is a mid-shelf lag deposit formed from shallower eroded material and thins seaward by downlap and landward by onlap. The youngest, Unit III, is interpreted to represent modern sediment deposition. Faults in the study area do not appear to offset the transgressive surface. The Newport Inglewood/Rose Canyon fault system is active in other regions to the south (e.g., La Jolla) where it offsets the transgressive surface and creates seafloor relief. Several shoals observed along the transgressive surface could record minor deformation due to fault activity in the study area. Nevertheless, our preferred interpretation is that the shoals are regions more resistant to erosion during marine transgression. The Cristianitos fault zone also causes a shoaling of the transgressive surface. This may be from resistant antecedent topography due to an early phase of compression on the fault. The Cristianitos fault zone was previously defined as a down-to-the-north normal fault, but the folding and faulting architecture imaged in the CHIRP data are more consistent with a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920048967&hterms=Barometers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBarometers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920048967&hterms=Barometers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBarometers"><span id="translatedtitle">Orthogonal stack of global tide gauge <span class="hlt">sea</span> <span class="hlt">level</span> data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Trupin, A.; Wahr, J.</p> <p>1990-01-01</p> <p>Yearly and monthly tide gauge <span class="hlt">sea</span> <span class="hlt">level</span> data from around the globe are fitted to numerically generated equilibrium tidal data to search for the 18.6 year lunar tide and 14 month pole tide. Both tides are clearly evident in the results, and their amplitudes and phases are found to be consistent with a global equilibrium response. Global, monthly <span class="hlt">sea</span> <span class="hlt">level</span> data from outside the Baltic <span class="hlt">sea</span> and Gulf of Bothnia are fitted to global atmospheric pressure data to study the response of the ocean to pressure fluctuations. The response is found to be inverted barometer at periods greater than two months. Global averages of tide gauge data, after correcting for the effects of post glacial rebound on individual station records, reveal an increase in <span class="hlt">sea</span> <span class="hlt">level</span> over the last 80 years of between 1.1 mm/yr and 1.9 mm/yr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5818426','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5818426"><span id="translatedtitle">Lowstand versus highstand <span class="hlt">eustatic</span> models for peat preservation: The coal-bearing rocks of the Breathitt Group, Eastern Kentucky</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chesnut, D.R. Jr.; Greb, S.F. . Kentucky Geological Survey)</p> <p>1992-01-01</p> <p>Stratigraphic and chronologic studies suggest that the alternation between major coal beds and clastic rocks of the Lower and Middle Pennsylvanian Breathitt Group (Central Appalachian Basin) resulted from glacial eustacy. The typical Coal-Clastic cycle starts at the top of a major coal bed and consists of a coarsening-upward sequence of marine or brackish-water strata which is commonly truncated and overlain by a fining-upward sequence. The fining-upward sequence is overlain by a rooted paleosol which is overlain by a coal bed. In one scenario, the peat is deposited during the stable highstand period. Because of subsidence, the highstand peat deposit is drowned and covered by marine sediments. During the subsequent lowstand the marine strata are eroded to varying degrees and bare channels are developed, causing an erosional unconformity surface on the marine strata. During transgression, the rise in base-<span class="hlt">level</span> causes sediments to aggrade within the channels, creating fining-upward sequences above the marine strata. Paleosol development and peat deposition begin again at the next highstand. In another scenario peats are deposited in a coastal setting during lowstand. As transgression proceeds from lowstand, channels backfill and all low-lying areas including peat are covered by coarsening-upward sequences. Peats are then deposited on exposed platforms during highstand. During the subsequent drop in <span class="hlt">sea</span> <span class="hlt">level</span>, channels are incised and highstand peats and part of the coarsening-upward sediment package is eroded. The second scenario implies a preservation bias to cyclothems caused by <span class="hlt">eustatic</span> rates being greater than subsidence rates. Peats are probably deposited during both lowstand and highstand, but lowstand peats are more likely to be preserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoJI.199.1018N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoJI.199.1018N"><span id="translatedtitle">Simultaneous estimation of lithospheric uplift rates and absolute <span class="hlt">sea</span> <span class="hlt">level</span> change in southwest Scandinavia from inversion of <span class="hlt">sea</span> <span class="hlt">level</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nielsen, Lars; Hansen, Jens Morten; Hede, Mikkel Ulfeldt; Clemmensen, Lars B.; Pejrup, Morten; Noe-Nygaard, Nanna</p> <p>2014-11-01</p> <p>Relative <span class="hlt">sea</span> <span class="hlt">level</span> curves contain coupled information about absolute <span class="hlt">sea</span> <span class="hlt">level</span> 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 for vertical lithospheric movement is essential for estimation of reliable values of absolute <span class="hlt">sea</span> <span class="hlt">level</span> change from relative <span class="hlt">sea</span> <span class="hlt">level</span> data and vise versa. For modern times, estimates of vertical lithospheric movement may be constrained by data (e.g. GPS-based measurements), which are independent from the relative <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> change rates for ancient times in areas where a dense coverage of relative <span class="hlt">sea</span> <span class="hlt">level</span> data exists and well-constrained average lithospheric movement values are known from, for example glacial isostatic adjustment (GIA) models. The inversion approaches are tested and used for simultaneous estimation of lithospheric uplift rates and absolute <span class="hlt">sea</span> <span class="hlt">level</span> change rates in southwest Scandinavia from modern relative <span class="hlt">sea</span> <span class="hlt">level</span> 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 of the obtained results. The two tested inversion schemes result in estimated absolute <span class="hlt">sea</span> <span class="hlt">level</span> rise of ˜1.2/1.3 mm yr-1 and vertical uplift rates ranging from approximately -1.4/-1.2 mm yr-1 (subsidence) to about 5.0/5.2 mm yr-1 if an a priori value of 1 mm yr-1 is used for the vertical lithospheric movement throughout the study area. In case the studied time interval is broken into two time intervals (before and after 1970), absolute <span class="hlt">sea</span> <span class="hlt">level</span> rise values of ˜0.8/1.2 mm yr-1 (before</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.7156C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.7156C"><span id="translatedtitle">The Enigma of 20th century <span class="hlt">sea</span> <span class="hlt">level</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cathles, Larry</p> <p>2014-05-01</p> <p><span class="hlt">Sea</span> <span class="hlt">level</span> has been constant at near-present <span class="hlt">levels</span> from ~5500 calendar years BP to the end of the Little Ice Age at ~1860 AD. Since ~1900, tide gauge measurements indicate that it has risen steadily at ~2 mm/yr by about 18 cm. The comparative stability of sealevel from 5500 cal yr BP to 1860 AD is robust, being suggested by near-shore Mediterranean archeological sites, the few <span class="hlt">sea</span> <span class="hlt">level</span> records that extend back to 1700 AD, and the impossibility of projecting the current <span class="hlt">sea</span> <span class="hlt">level</span> rise of ~2 mm/y back 5000 years (it would produce a global 10 m inundation, which is not observed) (Douglas et al., 2001, Academic Press). The post 1870 <span class="hlt">sea</span> <span class="hlt">level</span> rise is not due to heating of the upper ocean (Liviticus et al., 2000, Science). Munk (2002, PNAS) characterized it as an "enigma", dismissing an upper ocean steric <span class="hlt">sea</span> <span class="hlt">level</span> explanation as "too little" (~3 cm), "too late" (the rise started in 1860), and "too linear" (not accelerating with the accelerating CO2 increase). GRACE gravity measurements show a near zero change in ocean mass. Cazenave et al. (2009, Global and Planetary Change) indicate a slight decrease in ocean mass between 2003 and 2008. The rate of meltwater mass being added to the oceans essentially equals the GIA correction (Chambers et al., 2010, JGR). Different GIA models give ocean mass increase ranging from 0.5 to 2 mm/y of equivalent <span class="hlt">sea</span> <span class="hlt">level</span> rise. Our GIA model suggests no ocean mass increases (~0 mm/y of equivalent <span class="hlt">sea</span> <span class="hlt">level</span> rise). In this talk I show that the heating of a two layer ocean model driven by the temperature changes that have occurred over the last 1000 years since the peak of the Medieval Warm Period produces a ~2mm/yr linear <span class="hlt">sea</span> <span class="hlt">level</span> rise over the last 100 years with much smaller preceding <span class="hlt">sea</span> <span class="hlt">level</span> changes. Ocean mass could be unchanging over the last century as well as the last ~5000 years. This result is compatible with GRACE measurements and eclipse data constraints, predictions of our GIA model, and it resolves the enigma the 20th</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4150292','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4150292"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span>: measuring the bounding surfaces of the ocean</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tamisiea, Mark E.; Hughes, Chris W.; Williams, Simon D. P.; Bingley, Richard M.</p> <p>2014-01-01</p> <p>The practical need to understand <span class="hlt">sea</span> <span class="hlt">level</span> along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global <span class="hlt">sea</span> <span class="hlt">level</span>. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of <span class="hlt">sea-level</span> rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in <span class="hlt">sea</span> <span class="hlt">level</span>. While information from many scientific disciplines is needed to understand <span class="hlt">sea-level</span> change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the <span class="hlt">sea</span> surface and the Earth's crust. PMID:25157196</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25157196','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25157196"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span>: measuring the bounding surfaces of the ocean.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tamisiea, Mark E; Hughes, Chris W; Williams, Simon D P; Bingley, Richard M</p> <p>2014-09-28</p> <p>The practical need to understand <span class="hlt">sea</span> <span class="hlt">level</span> along the coasts, such as for safe navigation given the spatially variable tides, has resulted in tide gauge observations having the distinction of being some of the longest instrumental ocean records. Archives of these records, along with geological constraints, have allowed us to identify the century-scale rise in global <span class="hlt">sea</span> <span class="hlt">level</span>. Additional data sources, particularly satellite altimetry missions, have helped us to better identify the rates and causes of <span class="hlt">sea-level</span> rise and the mechanisms leading to spatial variability in the observed rates. Analysis of all of the data reveals the need for long-term and stable observation systems to assess accurately the regional changes as well as to improve our ability to estimate future changes in <span class="hlt">sea</span> <span class="hlt">level</span>. While information from many scientific disciplines is needed to understand <span class="hlt">sea-level</span> change, this review focuses on contributions from geodesy and the role of the ocean's bounding surfaces: the <span class="hlt">sea</span> surface and the Earth's crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMEP31A0830R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMEP31A0830R"><span id="translatedtitle">Modeling Floodplain Dynamics: Can the Ganges-Brahmaputra Delta keep pace with 21st Century <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rogers, K. G.; Overeem, I.</p> <p>2013-12-01</p> <p>The low-lying Ganges-Brahmaputra (G-B) Delta in Bangladesh is densely populated (~1200 people/km2) and could be flooded within the next century by rapid <span class="hlt">sea</span> <span class="hlt">level</span> rise and increased monsoonal rains. The G-B Rivers currently transport 1*109 tons of sediment from their basins in the Himalaya Mountains to the delta each year, with ~90% of the annual sediment load delivered during the Asian summer monsoon. Sediment distribution across the delta's surface by floods and coastal storms has kept pace with the rate of relative <span class="hlt">sea</span> <span class="hlt">level</span> rise along the Bengal coast, enabling the delta to maintain a positive elevation. However, ensemble Community Climate System Model experiments predict 11% higher monsoonal rainfall for the next century, potentially leading to extreme flooding events in the delta. Stratigraphic reconstructions show that sedimentation in the upper G-B floodplain was more than doubled under the Early Holocene enhanced monsoonal regime, suggesting that the delta may withstand an increase in monsoon intensity, flooding, and tropical cyclones that are currently predicted. Whether the G-B floodplains and coastal areas will ultimately drown under predicted <span class="hlt">sea</span> <span class="hlt">level</span> rise and monsoon intensification depends on a balance of aggradation, <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> rise and subsidence. To improve predictions of climatic forcing on aggradation rates in the lower G-B floodplain and coastal plain, direct sedimentation measurements collected in 2008 and 2012 in the lower delta are paired with a series of model components coupled within the Community Surface Dynamics Modeling System (CSDMS) Modeling Tool (CMT). We use three separate numerical models to simulate river basin sediment flux, floodplain sedimentation, and tidal-plain aggradation. The model inputs are based on available 20Th century climate and river gauge data, and outputs are compared to modern sedimentation rates within the G-B tidal delta and highly cultivated central coastal plain. The models are then used to test</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NLE.....5...37P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NLE.....5...37P"><span id="translatedtitle">Analysis of the <span class="hlt">sea</span> <span class="hlt">levels</span> in Kiribati A Rising <span class="hlt">Sea</span> of Misrepresentation Sinks Kiribati</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parker, Albert</p> <p>2016-03-01</p> <p>The <span class="hlt">sea</span> <span class="hlt">levels</span> of Kiribati have been stable over the last few decades, as elsewhere in the world. The Australian government funded Pacific <span class="hlt">Sea</span> <span class="hlt">Level</span> Monitoring (PSLM) project has adjusted <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">levels</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012QSRv...40...54C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012QSRv...40...54C"><span id="translatedtitle">Quantitative constraints on the <span class="hlt">sea-level</span> fall that terminated the Littorina <span class="hlt">Sea</span> Stage, southern Scandinavia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clemmensen, Lars B.; Murray, Andrew S.; Nielsen, Lars</p> <p>2012-04-01</p> <p>The island of Anholt in the Kattegat <span class="hlt">sea</span> (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 <span class="hlt">sea</span> <span class="hlt">level</span>. 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 <span class="hlt">sea-level</span>. Assuming a constant uplift rate of 1.2 mm/yr, the corresponding drop in absolute <span class="hlt">sea-level</span> is estimated to be around 2.6 m. This marked <span class="hlt">sea-level</span> 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 <span class="hlt">Sea</span> stage in the Baltic <span class="hlt">Sea</span> region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMPP12A0233B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMPP12A0233B"><span id="translatedtitle"><span class="hlt">Sea-level</span> and the `Stage 11 Problem`</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bowen, D. Q.</p> <p>2003-12-01</p> <p>Estimating an approximate relative <span class="hlt">sea</span> <span class="hlt">level</span> for oxygen isotope stage 11 may have a critical bearing on a solution to the `stage 11 problem` that identifies the mismatch between low eccentricity forcing and the disproportionate ice volume response - that also includes a relative <span class="hlt">sea</span> <span class="hlt">level</span> response. The perennial problem of separating ice volume from temperature effects has hampered attempts to estimate <span class="hlt">sea</span> <span class="hlt">level</span> from delta 18O data sets, even for younger odd numbered stages when comparisons with U-series ages on corals are available. Stage 11 <span class="hlt">sea</span> <span class="hlt">levels</span> on `stable` and uplifting coasts are recognised from geomorphic features such as terraces and shoreline angles, sediments and corals, and yield a range of estimates from over 20 m to just below present <span class="hlt">sea</span> <span class="hlt">level</span>. Given that the 413 ka Milankovitch pacing provides similar orbital configurations for stage 11 and the Holocene some interest attaches to the potential <span class="hlt">sea-level</span> similarity between them, especially for the future Holocene. Attempts to derive a stage 11 <span class="hlt">sea</span> <span class="hlt">level</span> from coasts uplifting at different rates have used `uplift correction graphs` or uplift correction equations, but a major handicap is the dearth of appropriate geochronologic ages both for stage 11 and substage 5e (5.5) - the base line for estimating average uplift rates. Different estimates for the age of stage 11 and 5e (5.5), and the duration of 5e, have yielded a range of estimates. Earlier estimates relied on single locations or regional evidence, but it is probably misleading to rely on these. To combat this several world-wide locations are assembled and, using locality-specific data, provide a mean estimate for the stage 11 <span class="hlt">sea</span> <span class="hlt">level</span> of 11 m, plus-minus 10 m. But by applying a set of standardised parameters (including the peak <span class="hlt">sea</span> <span class="hlt">level</span> at 402 ka - event 11.3 of the Bassinott time scale) the mean <span class="hlt">sea</span> <span class="hlt">level</span> for stage 11 emerges as 2 m plus-minus 7 m. This closes the gap between inferences from delta 18O variability, the latest of which point</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMEP13D3544B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMEP13D3544B"><span id="translatedtitle">Exploring Challenges and Opportunities in Recognizing the Signature of <span class="hlt">Sea</span> <span class="hlt">Level</span>, Tectonic Subsidence, and Sediment Supply in the Stratigraphic Record: A Comparison of Field-based and Model-generated Data from Carbonate Sedimentary Records</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brady, M. E.; Oliver, D. L.; Bowie, C.</p> <p>2014-12-01</p> <p>Integrating field and model observations of marine carbonate strata, we investigate how distinct sedimentary basins respond to the same <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> history, specifically in terms of the preserved record of lithofacies and meter-scale depositional cycles. First, we compare two coeval Devonian sedimentary records characterized by different subsidence regimes (North American 'stable' cratonic interior vs. 'passive' continental margin) and rock accumulation rates (measured over m.y. time scales). Despite the greater potential for subaerial exposure due to minimal accommodation space, stratigraphic and petrographic analyses revealed the apparently significant role of suppressed subtidal sedimentation rates, along with submarine erosion and non-deposition, in limiting both the thickness and number of facies and cycles preserved in the cratonic record compared to the continental margin. To explore insights gained from the field, we use a previously-developed, one-dimensional forward model to generate stratigraphic columns. Knowing the true history underlying each model run, we can test the sensitivity of the resultant stratigraphy to variation in subsidence and sedimentation rates, while maintaining the same <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> curve. For the model conditions explored, 1) thicker component depositional units reflect higher sedimentation rates; 2) total stratigraphic thickness, numbers of units, and stratigraphic completeness reflect combinations of low enough sedimentation rates and high enough subsidence rates to maintain sufficient accommodation space; and 3) the preserved stratal patterns rarely faithfully record <span class="hlt">sea</span> <span class="hlt">level</span> history. The model results lead to new questions that can direct future field studies. Overall, this approach can inform similar investigations in other carbonate, siliciclastic and non-marine records, especially over stratigraphic scales finer than the temporal resolution typically afforded by numerical ages and correlation techniques.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70141641','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70141641"><span id="translatedtitle"><span class="hlt">Sea-level</span>-induced seismicity and submarine landslide occurrence</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brothers, Daniel S.; Luttrell, Karen M.; Chaytor, Jason D.</p> <p>2013-01-01</p> <p>The temporal coincidence between rapid late Pleistocene <span class="hlt">sea-level</span> rise and large-scale slope failures is widely documented. Nevertheless, the physical mechanisms that link these phenomena are poorly understood, particularly along nonglaciated margins. Here we investigate the causal relationships between rapid <span class="hlt">sea-level</span> rise, flexural stress loading, and increased seismicity rates along passive margins. We find that Coulomb failure stress across fault systems of passive continental margins may have increased more than 1 MPa during rapid late Pleistocene–early Holocene <span class="hlt">sea-level</span> rise, an amount sufficient to trigger fault reactivation and rupture. These results suggest that <span class="hlt">sea</span>-level–modulated seismicity may have contributed to a number of poorly understood but widely observed phenomena, including (1) increased frequency of large-scale submarine landslides during rapid, late Pleistocene <span class="hlt">sea-level</span> rise; (2) emplacement of coarse-grained mass transport deposits on deep-<span class="hlt">sea</span> fans during the early stages of marine transgression; and (3) the unroofing and release of methane gas sequestered in continental slope sediments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DyAtO..64....1G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DyAtO..64....1G"><span id="translatedtitle">The statistical relation of <span class="hlt">sea-level</span> and temperature revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grassi, Stefano; Hillebrand, Eric; Ventosa-Santaulària, Daniel</p> <p>2013-11-01</p> <p>We propose a semi-empirical model for the relation between global mean surface temperature and global <span class="hlt">sea-levels</span>. In contradistinction to earlier approaches to this problem, the model allows for valid statistical inference and joint estimation of trend components and interaction term of temperature and <span class="hlt">sea-level</span>. Estimation of the model on the data set used in Rahmstorf (2007) yields a proportionality coefficient of 4.6 mm/year per °C at a one-sided significance <span class="hlt">level</span> of 7.6 percent or higher. Long-term simulations of the model result in a two-sided 90-percent confidence interval for the <span class="hlt">sea-level</span> rise in the year 2100 of [15 cm, 150 cm] above the 1990 <span class="hlt">level</span>. This is a wider margin of error than was reported in the previous literature, and it reflects the substantial uncertainty in relating two trending time series.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRC..118.3999M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRC..118.3999M"><span id="translatedtitle">A nonstationary analysis for the Northern Adriatic extreme <span class="hlt">sea</span> <span class="hlt">levels</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Masina, Marinella; Lamberti, Alberto</p> <p>2013-09-01</p> <p>The historical data from the Trieste, Venice, Porto Corsini, and Rimini tide gauges have been used to investigate the spatial and temporal changes in extreme high water <span class="hlt">levels</span> in the Northern Adriatic. A detailed analysis of annual mean <span class="hlt">sea</span> <span class="hlt">level</span> evolution at the three longest operating stations shows a coherent behavior both on a regional and global scale. A slight increase in magnitude of extreme water elevations, after the removal of the regularized annual mean <span class="hlt">sea</span> <span class="hlt">level</span> necessary to eliminate the effect of local subsidence and <span class="hlt">sea</span> <span class="hlt">level</span> rise, is found at the Venice and Porto Corsini stations. It seems to be mainly associated with a wind regime change occurred in the 1990s, due to an intensification of Bora wind events after their decrease in frequency and intensity during the second half of the 20th century. The extreme values, adjusted for the annual mean <span class="hlt">sea</span> <span class="hlt">level</span> trend, are modeled using a time-dependent GEV distribution. The inclusion of seasonality in the GEV parameters considerably improves the data fitting. The interannual fluctuations of the detrended monthly maxima exhibit a significant correlation with the variability of the large-scale atmospheric circulation represented by the North Atlantic Oscillation and Arctic Oscillation indices. The different coast exposure to the Bora and Sirocco winds and their seasonal character explain the various seasonal patterns of extreme <span class="hlt">sea</span> <span class="hlt">levels</span> observed at the tide gauges considered in the present analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17813199','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17813199"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> at southern california: a decadal fluctuation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Namias, J; Chi Kan Huang, J</p> <p>1972-07-28</p> <p>The winter mean height of <span class="hlt">sea</span> <span class="hlt">level</span> at southern California rose 5.6 centimeters between the periods 1948-1957 and 1958-1969. These periods correspond to two fairly coherent large-scale climatic regimes with different air-<span class="hlt">sea</span> coupling, which were previously identified. The rise was mainly due to a change in the thermohaline structure of the water as a result of changes in prevailing winds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMPP21B2236P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMPP21B2236P"><span id="translatedtitle">Trends in Plio-Pleistocene southwest Pacific stable isotope stratigraphy: Implications for orbital forcing of ice sheets and mid-Pliocene <span class="hlt">sea</span> <span class="hlt">level</span> estimates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patterson, M. O.; Mckay, R. M.; Naish, T.; Wilson, G. S.; Ohneiser, C.; Woodard, S. C.; Bostock, H. C.; Caballero-Gill, R. P.</p> <p>2015-12-01</p> <p>We present a new high resolution Early to mid-Pliocene (4.3 to 3.0 Ma) benthic stable isotope record (δ18O and δ13C), a revised magnetostratigraphy and an orbitally tuned age model extending the Early Pliocene to Early Pleistocene (4.3 to 1.2 Ma) record for ODP Site 1123. Placing the δ18O and δ13C time series on an orbital-scale age model provides the chronological basis for high-resolution proxy records spanning the Early Pliocene to Early Pleistocene. By comparison with previous published records (DSDP 607, ODP 1090/704, ODP 849, MV0502-AJC), we examine long-term changes in intra and inter-basinal benthic δ13C records in order to trace the ventilation history of deep-water masses. These comparisons highlight that during the warm Early to mid-Pliocene (3.6 to 2.7 Ma) South Atlantic and southwest Pacific gradients where much larger than during the Pleistocene. These findings are not consistent with Late Pleistocene and modern reconstructions in which South Atlantic δ13C values are slightly lower than south Pacific values at depths bathed by LCDW. Thus, indicating that while LCDW bathing the South Atlantic may have had an enhanced NADW signature, such a situation in the southwest Pacific did not exist during the warm mid-Pliocene. Furthermore, while the δ18O record from Site 1123 demonstrates an overall agreement with the global benthic δ18O stack LR04 exhibiting 40-kyr oscillations in ice volume/temperature, the mid to Late Pliocene interval (~3.3 to 2.8 Ma) demonstrates low frequency ice volume/temperature variability consistent with 100-kyr eccentricity. <span class="hlt">Eustatic</span> <span class="hlt">sea-level</span> estimates from δ18O values are consistent with all higher-end (22±10 m compared to modern) values for peak interglacial highstands between 2.9-3.2 Ma. Thus, inferring 100-kyr Antarctic ice sheet variability from marine based margins of the East Antarctic Ice Sheet (EAIS) during the mid to Late Pliocene contributed to <span class="hlt">sea</span> <span class="hlt">level</span>, whereas after ~2.9 Ma (post interglacial G17) ODP Site </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7389N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7389N"><span id="translatedtitle">Contribution of climate forcing to <span class="hlt">sea</span> <span class="hlt">level</span> variations in the Mediterranean <span class="hlt">Sea</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Natsiopoulos, Dimitrios A.; Vergos, Georgios S.; Tziavos, Ilias N.</p> <p>2016-04-01</p> <p>With the availability of an abundance of earth observation data from satellite altimetry missions as well as those from the ENVISAT and CRYOSAT-2 satellites, monitoring of the <span class="hlt">sea</span> <span class="hlt">level</span> variations is gaining increased importance. In this work, altimetric data sets from the satellite remote sensing missions of ENVISAT and CRYOSAT-2 have been used to study the variations of the Mediterranean <span class="hlt">sea</span> <span class="hlt">level</span>. Alongside, a correlation analysis of <span class="hlt">Sea</span> <span class="hlt">Level</span> Anomalies (SLAs) with global and regional climatic indexes that influence the ocean state, has been carried out as well. The raw data used were SLAs from the respective altimetric missions, acquired by the on-board altimeters from the ENVISAT satellite for seven consecutive years (2003-2009) and from the CRYOSAT-2 satellite for six consecutive years (2010-2015). Three oscillation indexes have been investigated, as representative of climate-change and seasonal forcing on the <span class="hlt">sea</span> <span class="hlt">level</span>. The first one was the well-known Southern Oscillation Index (SOI), the next one the North Atlantic Oscillation (NAO) index and the third, being primarily more representative of the Mediterranean <span class="hlt">sea</span> state, was the Mediterranean Oscillation Index (MOI). The possible correlation is investigated in both monthly and annual scales, while a regional multiple regression and a principal component analysis (PCA) between the SLAs and oscillation indexes is carried out. Multiple regression and PCA have been used as tools in order to deduce possible correlations between the Mediterranean <span class="hlt">sea</span> <span class="hlt">level</span> variations and the aforementioned oscillation indexes, under the assumption that SLA variations are driven by steric forcing. Finally, evidence of the <span class="hlt">sea</span> <span class="hlt">level</span> cyclo-stationarity in the Mediterranean <span class="hlt">Sea</span> is deduced from the analysis of empirically derived covariance functions at monthly intervals from the available SLA data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830041107&hterms=global+cooling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dglobal%2Bcooling','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830041107&hterms=global+cooling&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dglobal%2Bcooling"><span id="translatedtitle">Global mean <span class="hlt">sea</span> <span class="hlt">level</span> - Indicator of climate change</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Robock, A.; Hansen, J.; Gornitz, V.; Lebedeff, S.; Moore, E.; Etkins, R.; Epstein, E.</p> <p>1983-01-01</p> <p>A critical discussion is presented on the use by Etkins and Epstein (1982) of combined surface air temperature and <span class="hlt">sea</span> <span class="hlt">level</span> time series to draw conclusions concerning the discharge of the polar ice sheets. It is objected by Robock that they used Northern Hemisphere land surface air temperature records which are unrepresentative of global <span class="hlt">sea</span> surface temperature, and he suggests that externally imposed volcanic dust and CO2 forcings can adequately account for observed temperature changes over the last century, with global <span class="hlt">sea</span> <span class="hlt">level</span> changing in passive response to <span class="hlt">sea</span> change as a result of thermal expansion. Hansen et al. adduce evidence for global cooling due to ice discharge that has not exceeded a few hundredths of a degree centigrade in the last century, precluding any importance of this phenomenon in the interpretation of global mean temperature trends for this period. Etkins and Epstein reply that since their 1982 report additional evidence has emerged for the hypothesis that the polar ice caps are diminishing. It is reasserted that each of the indices discussed, including global mean <span class="hlt">sea</span> surface temperature and <span class="hlt">sea</span> <span class="hlt">level</span>, polar ice sheet mass balance, water mass characteristics, and the spin rate and axis of rotation displacement of the earth, are physically linked and can be systematically monitored, as is currently being planned under the auspices of the National Climate Program.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4718Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4718Z"><span id="translatedtitle">Long-period <span class="hlt">sea-level</span> variations in the Mediterranean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zerbini, Susanna; Raicich, Fabio; Bruni, Sara; del Conte, Sara; Errico, Maddalena; Prati, Claudio; Santi, Efisio</p> <p>2016-04-01</p> <p>Since the beginning of its long-lasting lifetime, the Wegener initiative has devoted careful consideration to studying <span class="hlt">sea-level</span> variations/changes across the Mediterranean <span class="hlt">Sea</span>. Our study focuses on several long-period <span class="hlt">sea-level</span> 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 <span class="hlt">sea-level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">levelling</span> 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 <span class="hlt">sea-level</span> 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 <span class="hlt">sea-level</span> 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 <span class="hlt">sea-level</span> records with physics</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EnMan..57..176H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EnMan..57..176H"><span id="translatedtitle">How Much Are Floridians Willing to Pay for Protecting <span class="hlt">Sea</span> Turtles from <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamed, Ahmed; Madani, Kaveh; Von Holle, Betsy; Wright, James; Milon, J. Walter; Bossick, Matthew</p> <p>2016-01-01</p> <p><span class="hlt">Sea</span> <span class="hlt">level</span> rise (SLR) is posing a great inundation risk to coastal areas. Some coastal nesting species, including <span class="hlt">sea</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> turtle habitat. The greatest indicators of whether or not an individual was willing to pay to protect <span class="hlt">sea</span> 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 <span class="hlt">sea</span> turtles having an effect on their life were also more likely to pay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26319030','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26319030"><span id="translatedtitle">How Much Are Floridians Willing to Pay for Protecting <span class="hlt">Sea</span> Turtles from <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hamed, Ahmed; Madani, Kaveh; Von Holle, Betsy; Wright, James; Milon, J Walter; Bossick, Matthew</p> <p>2016-01-01</p> <p><span class="hlt">Sea</span> <span class="hlt">level</span> rise (SLR) is posing a great inundation risk to coastal areas. Some coastal nesting species, including <span class="hlt">sea</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> 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 <span class="hlt">sea</span> turtle habitat. The greatest indicators of whether or not an individual was willing to pay to protect <span class="hlt">sea</span> 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 <span class="hlt">sea</span> turtles having an effect on their life were also more likely to pay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2277N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2277N"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">Level</span> Rise and Subsidence in the Gulf of Thailand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Niemnil, Sommart</p> <p></p> <p>In the Thailand -EC GEO2TECDI-SONG Project we investigate the <span class="hlt">sea</span> <span class="hlt">level</span> change and vertical land motion in Thailand. First, Bangkok is situated in river delta and average height is closed to <span class="hlt">sea</span> <span class="hlt">level</span>. 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 <span class="hlt">sea</span> <span class="hlt">levels</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> registration reveals the absolute <span class="hlt">sea</span> <span class="hlt">level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryID=158951','PESTICIDES'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryID=158951"><span id="translatedtitle">COASTAL SENSITIVITY TO <span class="hlt">SEA</span> <span class="hlt">LEVEL</span> RISE: A FOCUS ON ...</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>Synthesis and Assessment Product 4.1 will synthesize information from the ongoing mapping efforts by federal and non-federal researchers related to the implications of rising <span class="hlt">sea</span> <span class="hlt">level</span>. It will overlay the various data layers to develop new results made possible by bringing together researchers that are otherwise working independently. Because of time, data, and resource limitations, the synthesis will focus on a contiguous portion of the U.S. coastal zone (New York to North Carolina). The report will also develop a plan for <span class="hlt">sea</span> <span class="hlt">level</span> rise research to answer the questions that are most urgent for near-term decisionmaking. This report will address the implications of <span class="hlt">sea</span> <span class="hlt">level</span> rise on three spatial scales by providing: • A literature review that puts the report within the nationwide context. • Data overlays and a state-of-the-art quantitative assessment concerning coastal elevations, shore erosion, and wetland accretion for a multi-state study area along the U.S. Atlantic Coast: New York to North Carolina. • Qualitative discussions and case studies that document in greater detail the impact of <span class="hlt">sea</span> <span class="hlt">level</span> rise on smaller areas within the mid-Atlantic study area. This report will provide information that supports the specific goal in Chapter 9 of the Strategic Plan for the Climate Change Science Program (CCSP, 2003) to analyze how coastal environmental programs can be improved to adapt to <span class="hlt">sea</span> <span class="hlt">level</span> rise while enhancing economic growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70182742','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70182742"><span id="translatedtitle">Cenozoic <span class="hlt">sea</span> <span class="hlt">level</span> and the rise of modern rimmed atolls</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Toomey, Michael; Ashton, Andrew; Raymo, Maureen E.; Perron, J. Taylor</p> <p>2016-01-01</p> <p><span class="hlt">Sea-level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">levels</span> (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 <span class="hlt">sea</span> <span class="hlt">level</span> was higher than present. Carbonate dissolution through the subsequent <span class="hlt">sea-level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23379951','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23379951"><span id="translatedtitle">Impact of <span class="hlt">sea</span> <span class="hlt">level</span> rise on tide gate function.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Walsh, Sean; Miskewitz, Robert</p> <p>2013-01-01</p> <p><span class="hlt">Sea</span> <span class="hlt">level</span> rise resulting from climate change and land subsidence is expected to severely impact the duration and associated damage resulting from flooding events in tidal communities. These communities must continuously invest resources for the maintenance of existing structures and installation of new flood prevention infrastructure. Tide gates are a common flood prevention structure for low-lying communities in the tidal zone. Tide gates close during incoming tides to prevent inundation from downstream water propagating inland and open during outgoing tides to drain upland areas. Higher downstream mean <span class="hlt">sea</span> <span class="hlt">level</span> elevations reduce the effectiveness of tide gates by impacting the hydraulics of the system. This project developed a HEC-RAS and HEC-HMS model of an existing tide gate structure and its upland drainage area in the New Jersey Meadowlands to simulate the impact of rising mean <span class="hlt">sea</span> <span class="hlt">level</span> elevations on the tide gate's ability to prevent upstream flooding. Model predictions indicate that <span class="hlt">sea</span> <span class="hlt">level</span> rise will reduce the tide gate effectiveness resulting in longer lasting and deeper flood events. The results indicate that there is a critical point in the <span class="hlt">sea</span> <span class="hlt">level</span> elevation for this local area, beyond which flooding scenarios become dramatically worse and would have a significantly negative impact on the standard of living and ability to do business in one of the most densely populated areas of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.youtube.com/watch?v=dWz3s9OIIZQ','SCIGOVIMAGE-NASA'); return false;" href="http://www.youtube.com/watch?v=dWz3s9OIIZQ"><span id="translatedtitle">NASA Now: Climate Change: <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise</span></a></p> <p><a target="_blank" href="http://www.nasa.gov/multimedia/videogallery/index.html">NASA Video Gallery</a></p> <p></p> <p></p> <p>Dr. Josh Willis discusses the connection between oceans and global climate change. Learn why NASA measures greenhouse gases and how we detect ocean <span class="hlt">levels</span> from space. These are crucial vital signs ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1616781N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1616781N"><span id="translatedtitle">Holocene <span class="hlt">sea-level</span> changes in the Falkland Islands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newton, Tom; Gehrels, Roland; Daley, Tim; Long, Antony; Bentley, Mike</p> <p>2014-05-01</p> <p>In many locations in the southern hemisphere, relative <span class="hlt">sea</span> <span class="hlt">level</span> (RSL) reached its maximum position during the middle Holocene. This highstand is used by models of glacial isostatic adjustment (GIA) to constrain the melt histories of the large ice sheets, particularly Antarctica. In this paper we present the first Holocene <span class="hlt">sea-level</span> record from the Falkland Islands (Islas Malvinas), an archipelago located on the Patagonian continental shelf about 500 km east of mainland South America at a latitude of ca. 52 degrees. Unlike coastal locations in southernmost South America, Holocene <span class="hlt">sea-level</span> data from the Falklands are not influenced by tectonics, local ice loading effects and large tidal ranges such that GIA and ice-ocean mass flux are the dominant drivers of RSL change. Our study site is a salt marsh located in Swan Inlet in East Falkland, around 50 km southwest of Stanley. This is the largest and best developed salt marsh in the Falkland Islands. Cores were collected in 2005 and 2013. Lithostratigraphic analyses were complemented by analyses of foraminifera, testate amoebae and diatoms to infer palaeoenvironments. The bedrock, a Permian black shale, is overlain by grey-brown organic salt-marsh clay, up to 90 cm thick, which, in a landward direction, is replaced by freshwater organic sediments. Overlying these units are medium-coarse sands with occasional pebbles, up to 115 cm thick, containing tidal flat foraminifera. The sandy unit is erosively overlain by a grey-brown organic salt-marsh peat which extends up to the present surface. Further away from the <span class="hlt">sea</span> this unit is predominantly of freshwater origin. Based on 13 radiocarbon dates we infer that prior to ~9.5 ka <span class="hlt">sea</span> <span class="hlt">level</span> was several metres below present. Under rising <span class="hlt">sea</span> <span class="hlt">levels</span> a salt marsh developed which was suddenly drowned around 8.4 ka, synchronous with a <span class="hlt">sea-level</span> jump known from northern hemisphere locations. Following the drowning, RSL rose to its maximum position around 7 ka, less than 0.5 m above</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26PSL.399...74C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26PSL.399...74C"><span id="translatedtitle">The <span class="hlt">sea-level</span> fingerprint of a Snowball Earth deglaciation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Creveling, Jessica R.; Mitrovica, Jerry X.</p> <p>2014-08-01</p> <p>Cap dolostones are thought to represent deposition from <span class="hlt">seas</span> transgressing over formerly glaciated continental margins during Marinoan Snowball deglaciation. Nevertheless, facies associations within some cap dolostones indicate that an episode of regional regression punctuated these transgressive sequence tracts. To date, inferences of <span class="hlt">sea-level</span> change during and after the Marinoan Snowball deglaciation have been interpreted using simple, qualitative arguments. In the present study, we explore the full spatio-temporal variability of <span class="hlt">sea-level</span> change during Snowball deglaciation and its aftermath using a gravitationally self-consistent theory that accounts for the deformational, gravitational and rotational perturbations to <span class="hlt">sea</span> <span class="hlt">level</span> on a viscoelastic Earth model. The theory is applied to model Marinoan Snowball deglaciation on a generalized Ediacaran paleogeography with a synthetic continental ice-sheet distribution. We find that <span class="hlt">sea-level</span> change following a synchronous, rapid (2 kyr) collapse of Snowball ice cover will exhibit significant geographic variability, including site-specific histories that are characterized by syn-deglacial <span class="hlt">sea-level</span> fall or stillstand. Moreover, some sites that experience syn-deglacial transgression will continue to experience transgression in the post-deglacial phase. Taken together, these results suggest that <span class="hlt">sea-level</span> change recorded by strata capping Snowball glaciogenic units may reflect a more complicated trajectory than previously thought, including deposition that was not limited to the deglaciation phase. These simulations, as well as others that explore the response to asynchronous melting and deglaciation phases of longer duration, demonstrate that an episode of regional regression interrupting a cap dolostone transgressive sequence tract may reflect one of several processes (or their combination): (1) near field adjustment associated with rapid local melting during an otherwise global hiatus in deglaciation; (2) post</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=sea+AND+level&pg=4&id=EJ328737','ERIC'); return false;" href="http://eric.ed.gov/?q=sea+AND+level&pg=4&id=EJ328737"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">Level</span> Change, A Fundamental Process When Interpreting Coastal Geology and Geography.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Zeigler, John M.</p> <p>1985-01-01</p> <p>Discusses the meaning of <span class="hlt">sea</span> <span class="hlt">level</span> change and identifies the major factors responsible for this occurrence. Elaborates on the theory and processes involved in indirect measurement of changes in <span class="hlt">sea</span> volume. Also explains how crustal movement affects <span class="hlt">sea</span> <span class="hlt">level</span>. (ML)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=average+AND+temperature&pg=3&id=EJ290512','ERIC'); return false;" href="http://eric.ed.gov/?q=average+AND+temperature&pg=3&id=EJ290512"><span id="translatedtitle">Concerns--High <span class="hlt">Sea</span> <span class="hlt">Levels</span> and Temperatures Seen Next Century.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Ryan, Paul R.</p> <p>1984-01-01</p> <p>A National Research Council committee recently concluded that atmospheric carbon dioxide <span class="hlt">levels</span> will "most likely" double by late in the next century, causing an increase in the earth's average temperature. Effects of the increase on <span class="hlt">sea</span> <span class="hlt">levels</span>, global climate, and other parameters are discussed. (JN)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815002A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815002A"><span id="translatedtitle">Adapting coastal structures to a moving relative <span class="hlt">sea</span> <span class="hlt">level</span>: Roman Time geoarchaeological evidence from Posillipo promontory (Naples, Italy).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aucelli, Pietro; Cinque, Aldo; Giordano, Francesco; Mattei, Gaia; Pappone, Gerardo; Rizzo, Angela</p> <p>2016-04-01</p> <p> precisely measuring the present submersion of all remains, two paleo-<span class="hlt">sea</span> <span class="hlt">levels</span> has been detected: one for the 1st century BC at -4 / -5 m and another for the 1st century AD at -3 + -0.50 m. In conclusion, by comparing the relative palaeo-<span class="hlt">sea</span> <span class="hlt">level</span> we have found with the <span class="hlt">eustatic</span> curve (Lambeck et al 2011), it appears that Posillipo area suffered 2 +/- 0.3m of subsidence after the 1st century AD. Moreover, the new interpretations we present here, strongly suggest that Posillipo area was also affected by subsidence between the 1st century BC and the 1st century AD, when the landmass sank about 1.5/2.5 m. Eventhough these movements appear less strong than those recognized in the Campi Flegrei central caldera, our results prove that volcano-tectonic movements of at least metrical magnitude have occurred also outside the caldera. In terms of human adaptation to the subsidence-induced rise of <span class="hlt">sea</span> <span class="hlt">level</span> during Roman times, the archaeological remains of Marechiaro e Rosbery indicate that the villas were restructured closing the rooms submerged by the <span class="hlt">sea</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17..445M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17..445M"><span id="translatedtitle">Tracking multidecadal trends in <span class="hlt">sea</span> <span class="hlt">level</span> using coral microatolls</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Majewski, Jedrzej; Pham, Dat; Meltzner, Aron; Switzer, Adam; Horton, Benjamin; Heng, Shu Yun; Warrick, David</p> <p>2015-04-01</p> <p>Tracking multidecadal trends in <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea-level</span> change at multidecadal timescales associated with vertical land movements, climate induced <span class="hlt">sea-level</span> rise and other oceanographic phenomena such as the El Niño/Southern Oscillation (ENSO) or Indian Ocean Dipole (IOD) with the assumption that the highest <span class="hlt">level</span> of survival (HLS) of coral microatolls track <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea-level</span> 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 <span class="hlt">sea-level</span> reconstructions for 1950-2011. The <span class="hlt">sea-level</span> 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 <span class="hlt">levels</span> at multi decadal time scales and can be used as a proxy for relative <span class="hlt">sea</span> <span class="hlt">level</span> (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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011EOSTr..92..273F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011EOSTr..92..273F"><span id="translatedtitle">Rising <span class="hlt">sea</span> <span class="hlt">level</span> may cause decline of fringing coral reefs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Field, Michael E.; Ogston, Andrea S.; Storlazzi, Curt D.</p> <p>2011-08-01</p> <p>Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated <span class="hlt">sea</span> surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but <span class="hlt">sea</span> <span class="hlt">level</span> rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century <span class="hlt">sea</span> <span class="hlt">level</span> rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that <span class="hlt">sea</span> <span class="hlt">level</span> will rise in the coming century (1990-2090) by 2.2-4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of <span class="hlt">sea</span> <span class="hlt">level</span> rise [Grinsted et al., 2009; Milne et al., 2009].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70043010','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70043010"><span id="translatedtitle">Rising <span class="hlt">sea</span> <span class="hlt">level</span> may cause decline of fringing coral reefs</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Field, Michael E.; Ogston, Andrea S.; Storlazzi, Curt D.</p> <p>2011-01-01</p> <p>Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated <span class="hlt">sea</span> surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but <span class="hlt">sea</span> <span class="hlt">level</span> rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century <span class="hlt">sea</span> <span class="hlt">level</span> rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that <span class="hlt">sea</span> <span class="hlt">level</span> will rise in the coming century (1990–2090) by 2.2–4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of <span class="hlt">sea</span> <span class="hlt">level</span> rise [Grinsted et al., 2009; Milne et al., 2009].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70036289','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70036289"><span id="translatedtitle">Rising <span class="hlt">sea</span> <span class="hlt">level</span> may cause decline of fringing coral reefs</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Field, M.E.; Ogston, A.S.; Storlazzi, C.D.</p> <p>2011-01-01</p> <p>Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated <span class="hlt">sea</span> surface temperatures and increased ocean acidity [e.g., Kleypas et al., 1999; Hoegh-Guldberg et al., 2007], but <span class="hlt">sea</span> <span class="hlt">level</span> rise, another consequence of climate change, is also likely to increase sedimentary processes that potentially interfere with photosynthesis, feeding, recruitment, and other key physiological processes (Figure 1). Anderson et al. [2010] argue compellingly that potential hazardous impacts to coastlines from 21st-century <span class="hlt">sea</span> <span class="hlt">level</span> rise are greatly underestimated, particularly because of the rapid rate of rise. The Intergovernmental Panel on Climate Change estimates that <span class="hlt">sea</span> <span class="hlt">level</span> will rise in the coming century (1990-2090) by 2.2-4.4 millimeters per year, when projected with little contribution from melting ice [Meehl et al., 2007]. New studies indicate that rapid melting of land ice could substantially increase the rate of <span class="hlt">sea</span> <span class="hlt">level</span> rise [Grinsted et al., 2009; Milne et al., 2009].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Rising+AND+sea+AND+levels&id=EJ389555','ERIC'); return false;" href="http://eric.ed.gov/?q=Rising+AND+sea+AND+levels&id=EJ389555"><span id="translatedtitle">The Significance of Rising <span class="hlt">Sea</span> <span class="hlt">Levels</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Conway, Gregory J.</p> <p>1989-01-01</p> <p>Describes an activity in which students graph changes in tides and ocean <span class="hlt">levels</span> over a period in order to obtain a visual representation of the changes taking place and their effects upon the Earth. Provides questions for students to answer after construction of the graphs. (RT)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.G14A..04P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.G14A..04P"><span id="translatedtitle">Impact of global seismicity on <span class="hlt">sea</span> <span class="hlt">level</span> changes assessment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piersanti, A.; Melini, D.</p> <p>2006-12-01</p> <p>Seismic events alter the equilibrium state of the solid Earth and perturbate its gravitational field. Consequently, they are also likely to produce <span class="hlt">sea</span> <span class="hlt">level</span> variations. The perturbation of the Earth's gravity field due to internal mass redistribution following a seismic event affects the geoid and it is therefore responsible for a variation in the absolute <span class="hlt">sea</span> <span class="hlt">level</span>. The vertical deformation of the seafloor, together with the geoid change, produces also a relative <span class="hlt">sea</span> <span class="hlt">level</span> change. Here we quantify the contribution of last century global seismic activity to sealevel addressing also the problem of ocean volume conservation and discussing the physical reasons for the particular pattern of rise and fall. Our results show that, though small, the seismic induced signal on relative sealevel is not negligible also on global scale and that, in several extended oceanic regions, it could give an important contribution to the total detected trend.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.6478W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.6478W"><span id="translatedtitle">A new perspective on global mean <span class="hlt">sea</span> <span class="hlt">level</span> (GMSL) acceleration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watson, Phil J.</p> <p>2016-06-01</p> <p>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 <span class="hlt">sea</span> <span class="hlt">level</span>. By virtue, over recent years, the issue of whether or not there is a measurable acceleration in global mean <span class="hlt">sea</span> <span class="hlt">level</span> has resulted in fierce, widespread professional, social, and political debate. Attempts to measure acceleration in global mean <span class="hlt">sea</span> <span class="hlt">level</span> (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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950046393&hterms=Barometers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBarometers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950046393&hterms=Barometers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBarometers"><span id="translatedtitle">Geosat observations of <span class="hlt">sea</span> <span class="hlt">level</span> response to barometric pressure forcing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoar, Timothy J.; Wilson, Clark R.</p> <p>1994-01-01</p> <p>Altimeter and <span class="hlt">sea</span> <span class="hlt">level</span> pressure data from the Geosat mission are analyzed for evidence of inverted barometer responses of <span class="hlt">sea</span> <span class="hlt">level</span> to atmospheric pressure forcing. Estimates of the inverted barometer coefficient are given for a variety of geographic regions and time scales using various orbit error removal strategies. There is some sensitivity to the orbit error removal method, but the estimated coefficients show a clear latitudinal dependence and are generally between -0.5 cm/mbar and -0.9 cm/mbar. The southern oceans respond slightly more like an inverted barometer than the northern oceans for similar latitudes. The regression exhibits significant geographic variability, particularly near major circulation features and in the northern hemisphere. The results suggest that the inverted barometer approximation is resonable over much of the oceans, but that some <span class="hlt">sea</span> <span class="hlt">level</span> variability may be correlated with barometric pressure by means other than the inverted barometer effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19770059848&hterms=tsunami&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtsunami','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19770059848&hterms=tsunami&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtsunami"><span id="translatedtitle">A <span class="hlt">sea-level</span> recorder for tectonic studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bilham, R.</p> <p>1977-01-01</p> <p>In the past tide gauges have provided valuable information concerning the vertical ground deformation associated with major earthquakes. Although tide-gauge data contains numerous sources of noise, a spacing of less than 40 km between gauges is indicated for a useful study of dilatant behavior, and a spacing of less than 80 km may be adequate for the study of crustal downwarping in island arcs. An inexpensive tide gauge which is designed to provide a continuous record of <span class="hlt">sea</span> <span class="hlt">level</span> with a measurement precision of 1 mm is described. Hydraulic filtering is incorporated into the instrument to attenuate daily tides relative to longer period variations of <span class="hlt">sea</span> <span class="hlt">level</span>. The instrument is designed to operate from flashlight batteries for a year unattended and to withstand temporary submersion as might be caused by tsunamis. Several of these <span class="hlt">sea-level</span> recorders have been installed in seismic gaps in the Aleutians and in the Caribbean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26ES...52a2065X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26ES...52a2065X"><span id="translatedtitle">Spatial-temporal analysis of <span class="hlt">sea</span> <span class="hlt">level</span> changes in China <span class="hlt">seas</span> and neighboring oceans by merged altimeter data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Yao; Zhou, Bin; Yu, Zhifeng; Lei, Hui; Sun, Jiamin; Zhu, Xingrui; Liu, Congjin</p> <p>2017-01-01</p> <p>The knowledge of <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">seas</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> anomaly gridding product. The <span class="hlt">sea</span> <span class="hlt">level</span> rising rate is 0.39 cm/yr in China <span class="hlt">Seas</span> and the neighboring oceans, 0.37 cm/yr in the Bo and Yellow <span class="hlt">Sea</span>, 0.29 cm/yr in the East China <span class="hlt">Sea</span> and 0.40 cm/yr in the South China <span class="hlt">Sea</span>. The mean <span class="hlt">sea</span> <span class="hlt">level</span> and its rising rate are spatial-temporal non-homogeneous. The mean <span class="hlt">sea</span> <span class="hlt">level</span> shows opposite characteristics in coastal <span class="hlt">seas</span> versus open oceans. The Bo and Yellow <span class="hlt">Sea</span> 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 <span class="hlt">seas</span> is stronger than that in open oceans, especially the <span class="hlt">seas</span> off the entrance area of the river, indicating that the validation of altimeter data is less reasonable in these <span class="hlt">seas</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16..601P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16..601P"><span id="translatedtitle">The imprint of <span class="hlt">sea-level</span> changes in the Southeastern Iberian continental shelf, Western Mediterranean <span class="hlt">Sea</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pinna, Andrea; Lastras, Galderic; Acosta, Juan; Muñoz, Araceli; Canals, Miquel</p> <p>2014-05-01</p> <p>A detailed morphologic analysis of the Southeastern Iberian continental shelf, Western Mediterranean <span class="hlt">Sea</span>, between the Mar Menor and the Gulf of Almería, based on swath bathymetry data, has revealed a number of seafloor features that we attribute to the imprint of <span class="hlt">sea-level</span> changes since the last glacial maximum. The continental shelf has been divided in four different domains with contrasting characteristics: the Mar Menor sector, the Mazarrón and Vera sector, the Gata Cape shelf and the Gulf of Almería shelf. The Mar Menor sector displays an up to 40 km wide shelf with a very low slope gradient, which contrasts with the Mazarrón and Vera shelf, with a width ranging between 0.4 and 5 km, severely incised by the different branches of the Garrucha submarine canyon. On each of these sectors, a variety of morphologies such as crests and escarpments have been identified. Most of these crests and escarpments can be followed for distances exceeding 15 km, and are located at constant, characteristic water depths. We interpret these structures as the result of relatively short-lived <span class="hlt">sea-level</span> still-stands and thus as palaeo-coastlines. Taking into account subsidence, we have correlated their bathymetric position with published post-MIS-5 Mediterranean <span class="hlt">sea-level</span> evolution curves, allowing the attribution of an approximate age for each interpreted palaeo-coastline. The last <span class="hlt">sea-level</span> regression is partially registered in the smooth Mar Menor shelf, where different crests and escarpments are cut by a LGM palaeo-channel, whereas all the sectors display structures related to the last <span class="hlt">sea-level</span> transgression. The continuity of these structures along all the sectors has allowed reconstructing the evolution of the coastline during the last <span class="hlt">sea-level</span> transgression, and thus inferring the palaeo-landscape of this sector of the Southeastern Iberian coast at different stages since 18 ka BP until the present.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC21C1101K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC21C1101K"><span id="translatedtitle">Attribution of Annual Maximum <span class="hlt">Sea</span> <span class="hlt">Levels</span> to Tropical Cyclones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khouakhi, A.; Villarini, G.</p> <p>2015-12-01</p> <p>Tropical cyclones (TCs) can cause catastrophic storm surges with major social, economic, and ecological impacts in coastal areas. Understanding the contribution of TCs to extreme <span class="hlt">sea</span> <span class="hlt">levels</span> is therefore essential. In this work we examine the contribution of TCs to annual maximum <span class="hlt">sea</span> <span class="hlt">levels</span> at the global scale, including potential climate controls and temporal changes. Complete global coverage (1842-2014) of historical 6-hour best track TC records are obtained from the International Best Track Archive for Climate Stewardship (IBTrACS) data set. Hourly tide gauge data are obtained from the Joint Archive for <span class="hlt">Sea</span> <span class="hlt">Level</span> Research Quality Data Set. There are 177 tide gauge stations with at least 25 complete years of data between 1970 and 2014 (a complete year is defined as having more than 90% of all the hourly measurements in a year). We associate an annual maximum <span class="hlt">sea</span> <span class="hlt">level</span> at a given station with a TC if the center of circulation of the storm passed within a certain distance from the station within a given time window. Spatial and temporal sensitivity analyses are performed with varying time windows (6h, 12h) and buffer zones (200km and 500km) around the tide gauge stations. Results highlight large regional differences, with some locations experiencing almost ¾ of their annual maxima during the passage of a TC. The attribution of annual maximum <span class="hlt">sea</span> <span class="hlt">level</span> to TCs is particularly high along the coastal areas of the eastern United States, the Gulf of Mexico, China, Japan, Taiwan and Western Australia. Further analyses will examine the role played by El Niño - Southern Oscillation and the potential temporal changes in TC contributions to annual maximum <span class="hlt">sea</span> <span class="hlt">levels</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810735V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810735V"><span id="translatedtitle">Uncertainties in <span class="hlt">sea</span> <span class="hlt">level</span> projections on twenty-year timescales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vinogradova, Nadya; Davis, James; Landerer, Felix; Little, Chris</p> <p>2016-04-01</p> <p>Regional decadal changes in <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> trends, the uncertainties of each processes must be reflected in the <span class="hlt">sea</span> <span class="hlt">level</span> calculations. Here we explore uncertainties in predictions of the decadal and bi-decadal changes in regional <span class="hlt">sea</span> <span class="hlt">level</span> induced by the changes in ocean dynamics and associated redistribution of heat and freshwater (often referred to as dynamic <span class="hlt">sea</span> <span class="hlt">level</span>). 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 <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span>. 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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24305147','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24305147"><span id="translatedtitle">Coastal flooding by tropical cyclones and <span class="hlt">sea-level</span> rise.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Woodruff, Jonathan D; Irish, Jennifer L; Camargo, Suzana J</p> <p>2013-12-05</p> <p>The future impacts of climate change on landfalling tropical cyclones are unclear. Regardless of this uncertainty, flooding by tropical cyclones will increase as a result of accelerated <span class="hlt">sea-level</span> rise. Under similar rates of rapid <span class="hlt">sea-level</span> rise during the early Holocene epoch most low-lying sedimentary coastlines were generally much less resilient to storm impacts. Society must learn to live with a rapidly evolving shoreline that is increasingly prone to flooding from tropical cyclones. These impacts can be mitigated partly with adaptive strategies, which include careful stewardship of sediments and reductions in human-induced land subsidence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.H53C0483S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.H53C0483S"><span id="translatedtitle">The Impact of <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise on Florida's Everglades</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Senarath, S. U.</p> <p>2005-12-01</p> <p>Global warming and the resulting melting of polar ice sheets could increase global <span class="hlt">sea</span> <span class="hlt">levels</span> significantly. Some studies have predicted mean <span class="hlt">sea</span> <span class="hlt">level</span> increases in the order of six inches to one foot in the next 25 to 50 years. This could have severe irreversible impacts on low-lying areas of Florida's Everglades. The key objective of this study is to evaluate the effects of a one foot <span class="hlt">sea</span> <span class="hlt">level</span> rise on Cape Sable Seaside Sparrow (CSSS) nesting areas within the Everglades National Park (ENP). A regional-scale hydrologic model is used to assess the sensitivities of this <span class="hlt">sea-level</span> rise scenario. Florida's Everglades supports a unique ecosystem. At present, about 50 percent of this unique ecosystem has been lost due to urbanization and farming. Today, the water flow in the remnant Everglades is also regulated to meet a variety of competing environmental, water-supply and flood-control needs. A 30-year, eight billion dollar (1999 estimate) project has been initiated to improve Everglades' water flows. The expected benefits of this restoration project will be short-lived if the predicted <span class="hlt">sea</span> <span class="hlt">level</span> rise causes severe impacts on the environmentally sensitive areas of the Everglades. Florida's Everglades is home to many threatened and endangered species of wildlife. The Cape Sable Seaside Sparrow population in the ENP is one such species that is currently listed as endangered. Since these birds build their nests close to the ground surface (the base of the nest is approximately six inches from the ground surface), they are directly affected by any <span class="hlt">sea</span> <span class="hlt">level</span> induced ponding depth, frequency or duration change. Therefore, the CSSS population serves as a good indicator species for evaluating the negative impacts of <span class="hlt">sea</span> <span class="hlt">level</span> rise on the Everglades' ecosystem. The impact of <span class="hlt">sea</span> <span class="hlt">level</span> rise on the CSSS habitat is evaluated using the Regional Simulation Model (RSM) developed by the South Florida Water Management District. The RSM is an implicit, finite-volume, continuous</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1172858','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1172858"><span id="translatedtitle">Land-ice modeling for <span class="hlt">sea-level</span> prediction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lipscomb, William H</p> <p>2010-06-11</p> <p>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 <span class="hlt">sea-level</span> predictions. However, the least certain and potentially greatest contributions to 21st century <span class="hlt">sea-level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900040662&hterms=sea+level+rise&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsea%2Blevel%2Brise','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900040662&hterms=sea+level+rise&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsea%2Blevel%2Brise"><span id="translatedtitle">Spectroscopic analysis of global tide gauge <span class="hlt">sea</span> <span class="hlt">level</span> data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Trupin, A.; Wahr, J.</p> <p>1990-01-01</p> <p>Yearly and monthly global tide-gage <span class="hlt">sea-level</span> data are fitted to numerically generated tidal data in order to search for the 18.6-yr lunar nodal tide and 14-month pole tide. Both of these tides are clearly evident, with amplitudes and phases that are consistent with a global equilibrium response. The ocean's response to atmospheric pressure is studied with the least-squares fit technique. Consideration is given to the global rise in <span class="hlt">sea</span> <span class="hlt">level</span>, the effects of postglacial rebound, and the possible causes of the enhanced pole tides in the North <span class="hlt">Sea</span>, the Baltic <span class="hlt">Sea</span>, and the Gulf of Bothnia. The results support O'Connor's (1986) suggestion that the enhanced pole tide in these regions is due to meteorological forcing rather than a basin-scale resonance. Also, the global average of the tide-gage data show an increase in <span class="hlt">sea</span> <span class="hlt">level</span> over tha last 80 yr of between 1.1 and 1.9 mm/yr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1721S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1721S"><span id="translatedtitle">Mean and extreme <span class="hlt">sea</span> <span class="hlt">level</span> changes in the southwestern Baltic <span class="hlt">Sea</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, Jessica; Patzke, Justus; Dangendorf, Sönke; Arns, Arne; Jensen, Jürgen; Fröhle, Peter</p> <p>2016-04-01</p> <p>In this contribution an overview over the BMBF project AMSeL_Ostsee (2015-2018) for the assessment of mean and extreme <span class="hlt">sea</span> <span class="hlt">level</span> changes over the past 150 years in the southwestern Baltic <span class="hlt">Sea</span> is presented. We compile several high resolution tide gauge records provided by the Water and Shipping Administration (WSV) along the German Baltic <span class="hlt">Sea</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">levels</span> independently to prove whether observed changes in extremes are either due to an underlying trend on mean <span class="hlt">sea</span> <span class="hlt">levels</span> or changes in storminess. References: Wahl, T., Jensen, J., Frank, T. (2011): On analysing <span class="hlt">sea</span> <span class="hlt">level</span> rise in the German Bight since 1844, NHESS, 10, 171-179.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70016434','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70016434"><span id="translatedtitle">Cenozoic prograding sequences of the Antarctic continental margin: a record of glacio-<span class="hlt">eustatic</span> and tectonic events</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cooper, A. K.; Barrett, P.J.; Hinz, K.; Traube, V.; Letichenkov, G.; Stagg, H.M.J.</p> <p>1991-01-01</p> <p> times, like today, by little or no clastic sedimentation on the continental shelf other than beneath retreated ice shelves lying far from the continental sheld edge. Ice streams carve broad depressions across the shelf and carry abundant basal sediments directly to the continental shelf edge, thereby creating troughmouth fans and sheet-like prograding sequences (i.e. type IA sequences). Numerous acoustic unconformities and multiple overcompacted layers within the prograding sequences suggest major fluctuations of the Antarctic Ice Sheet. The available drilling and seismic interpretations provide the following history: (1) Cenozoic ice sheets have existed in places near the continental shelf since middle to late Eocene time. (2) A grounded Antarctic ice sheet first expanded to the continental shelf edge, with probable overdeepening of the outer shelf, in late Eucene to early Oligocene time in Prydz Bay, possibly in early Miocene time in the Ross <span class="hlt">Sea</span>, and at least by middle Miocene time in the Weddell <span class="hlt">Sea</span>. (3) The relative amounts of shelf prograding and inferred ice-volume variations (and related <span class="hlt">sea-level</span> changes) have increased since middle to late Miocene time in the eastern Ross <span class="hlt">Sea</span>, Prydz Bay, and possibly Weddell <span class="hlt">Sea</span>. Our analysis is preliminary. Further acoustic surveys and scientific drilling are needed to resolve the proximal Antarctic record of glacio-<span class="hlt">eustatic</span>, climatic, and tectonic events recorded by the prograding sequences. ?? 1991.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T43F2729D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T43F2729D"><span id="translatedtitle">The Time Dependance of Dynamic Topography: Mantle Dynamic Contributions to Local and Global <span class="hlt">Sea-Level</span> Histories</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Durbin, C. J.; Shahnas, M.; Peltier, W. R.</p> <p>2012-12-01</p> <p> model to be employed to study the present state of the mantle and its evolution in the recent geological past. The predictions of the model that interest us are those of the rate of uplift and depression of the crust that contribute to records of relative <span class="hlt">sea</span> <span class="hlt">level</span> history over timescales sufficiently long to encompass several Late Quaternary glacial cycles. We employ a number of available local records of the time dependence of dynamical topography such as the coral based Barbados record of Peltier and Fairbanks (2006, QSR 25, pp. 3322-3337) to first demonstrate the accuracy with which the convection model is able to reconcile such observational constraints. Although several of the best available constraint data sets derive from regions in the near vicinity of active subduction zones, we proceed to apply the model's predictions to a number of (assumed to be) passive continental margins from which data have been derived that have been assumed to represent variations in <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> due to the variation of continental land ice volume such as those recently discussed by Miller et al. (2012, Geology 20, pp. 407-410). We assess the extent to which the passive continental margin assumption may have led to significant errors in the inference of global <span class="hlt">sea</span> <span class="hlt">level</span> rise for the mid-Pliocene interval of time centered upon 3 Ma.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.G21B0820F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.G21B0820F"><span id="translatedtitle">Mass-induced [|#8#|]<span class="hlt">Sea</span> <span class="hlt">Level</span> Variations in the Red <span class="hlt">Sea</span> from Satellite Altimetry and GRACE</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, W.; Lemoine, J.; Zhong, M.; Hsu, H.</p> <p>2011-12-01</p> <p>We have analyzed mass-induced <span class="hlt">sea</span> <span class="hlt">level</span> variations (SLVs) in the Red <span class="hlt">Sea</span> from steric-corrected altimetry and GRACE between January 2003 and December 2010. The steric component of SLVs in the Red <span class="hlt">Sea</span> calculated from climatological temperature and salinity data is relatively small and anti-phase with the mass-induced SLV. The total SLV in the Red <span class="hlt">Sea</span> is mainly driven by the mass-induced SLV, which increases in winter when the Red <span class="hlt">Sea</span> gains the water mass from the Gulf of Aden and vice versa in summer. Spatial and temporal patterns of mass-induced SLVs in the Red <span class="hlt">Sea</span> from steric-corrected altimetry agree very well with GRACE observations. Both of two independent observations show high annual amplitude in the central Red <span class="hlt">Sea</span> (>20cm). Total mass-induced SLVs in the Red <span class="hlt">Sea</span> from two independent observations have similar annual amplitude and phase. One main purpose of our work is to see whether GRGS's ten-day GRACE results can observe intra-seasonal mass change in the Red <span class="hlt">Sea</span>. The wavelet coherence analysis indicates that GRGS's results show the high correlation with the steric-corrected SLVs on intra-seasonal time scale. The agreement is excellent for all the time-span until 1/3 year period and is patchy between 1/3 and 1/16 year period. Furthermore, water flux estimates from current-meter arrays and moorings show mass gain in winter and mass loss in summer, which is also consistent with altimetry and GRACE.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ERL.....7b1001R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ERL.....7b1001R"><span id="translatedtitle"><span class="hlt">Sea-level</span> rise: towards understanding local vulnerability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rahmstorf, Stefan</p> <p>2012-06-01</p> <p>Projections of global <span class="hlt">sea-level</span> rise into the future have become more pessimistic over the past five years or so. A global rise by more than one metre by the year 2100 is now widely accepted as a serious possibility if greenhouse gas emissions continue unabated. That is witnessed by the scientific assessments that were made since the last IPCC report was published in 2007. The Delta Commission of the Dutch government projected up to 1.10 m as a 'high-end' scenario (Vellinga et al 2009). The Scientific Committee on Antarctic Research (SCAR) projected up to 1.40 m (Scientific Committee on Antarctic Research 2009), and the Arctic Monitoring and Assessment Programme (AMAP) gives a range of 0.90-1.60 m in its 2011 report (Arctic Monitoring and Assessment Programme 2011). And recently the US Army Corps of Engineers recommends using a 'low', an 'intermediate' and a 'high' scenario for global <span class="hlt">sea-level</span> rise when planning civil works programmes, with the high one corresponding to a 1.50 m rise by 2100 (US Army Corps of Engineers 2011). This more pessimistic view is based on a number of observations, most importantly perhaps the fact that <span class="hlt">sea</span> <span class="hlt">level</span> has been rising at least 50% faster in the past decades than projected by the IPCC (Rahmstorf et al 2007, IPCC 2007). Also, the rate of rise (averaged over two decades) has accelerated threefold, from around 1 mm yr-1 at the start of the 20th century to around 3 mm yr-1 over the past 20 years (Church and White 2006), and this rate increase closely correlates with global warming (Rahmstorf et al 2011). The IPCC projections, which assume almost no further acceleration in the 20th century, thus look less plausible. And finally the observed net mass loss of the two big continental ice sheets (Van den Broeke et al 2011) calls into question the assumption that ice accumulation in Antarctica would largely balance ice loss from Greenland in the course of further global warming (IPCC 2007). With such a serious <span class="hlt">sea-level</span> rise on the horizon</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.5134U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.5134U"><span id="translatedtitle">Steric <span class="hlt">sea</span> <span class="hlt">level</span> change in the Bay of Bengal: investigating the most variable component of <span class="hlt">sea</span> <span class="hlt">level</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uebbing, Bernd; Kusche, Jürgen; Rietbroek, Roelof; Shum, Ck</p> <p>2015-04-01</p> <p>Regional <span class="hlt">sea</span> <span class="hlt">level</span> change is influenced by contributions from mass sources, like melting of glaciers and the ice-sheets in Greenland and Antarctica, as well as steric contributions from changes in temperature and salinity of the oceans. Radar altimetry indicates a <span class="hlt">sea</span> <span class="hlt">level</span> trend in the Bay of Bengal of about 6 mm- yr over the time period of 2002-2014, which is significantly larger than the global mean trend. Here, we explain 80% of this rise by steric contributions and 20% by mass-related contributions. The increased rise of <span class="hlt">sea</span> <span class="hlt">level</span> in the Bay of Bengal threatens the coastal vulnerability of the surrounding countries like Bangladesh, where this effect is exacerbated in combination with land subsidence of the very low lying coastal areas. The BanD-AID (Bangladesh Delta: Assessment of the Causes of <span class="hlt">Sea-level</span> Rise Hazards and Integrated Development of Predictive Modeling Towards Mitigation and Adaptation) project tries to assess the current and future <span class="hlt">sea</span> <span class="hlt">level</span> rise and its impacts on the people living in the threatened coastal areas. As a part of this, it is necessary to analyze the different mass and steric contributors to the total <span class="hlt">sea</span> <span class="hlt">level</span> rise to aid in the prediction of future risks. We use data from radar altimetry and the GRACE mission to separate the total <span class="hlt">sea</span> <span class="hlt">level</span> rise into contributions from mass sources and steric changes. In our approach, temporal GRACE gravity data and Jason-1 and -2 along track altimetry data are fitted to time invariant spatial patterns (fingerprints) to avoid problems with GRACE resolution, filtering, geocenter and related issues. Our results show that in the Bay of Bengal the steric component is influenced by annual and interannual phenomena and, at the same time, it is significantly larger compared to the individual mass contributions, which show a linear and relatively stable behavior over time. We validate the steric component of our inversion by comparing it to independent steric estimates from 4-D gridded temperature and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.G51A0146M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.G51A0146M"><span id="translatedtitle">Monitoring <span class="hlt">Sea</span> <span class="hlt">Level</span> At L'Estartit, Spain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martinez-Benjamin, J.; Ortiz Castellon, M.; Martinez-Garcia, M.; Talaya, J.; Rodriguez Velasco, G.; Perez, B.</p> <p>2007-12-01</p> <p><span class="hlt">Sea</span> <span class="hlt">level</span> is an environmental variable which is widely recognised as being important in many scientific disciplines as a control parameter for coastal dynamical processes or climate processes in the coupled atmosphere-ocean systems, as well as engineering applications. A major source of <span class="hlt">sea-level</span> data are the national networks of coastal tide gauges, in Spain belonging to different institutions as the Instituto Geográfico Nacional (IGN), Puertos del Estado (PE), Instituto Hidrográfico de la Marina (IHM), Ports de la Generalitat, etc. Three Begur Cape experiences on radar altimeter calibration and marine geoid mapping made on 1999, 2000 and 2002 are overviewed. The marine geoid has been used to relate the coastal tide gauge data from l'Estartit harbour to off-shore altimetric data. The necessity to validate and calibrate the satellite's altimeter due to increasing needs in accuracy and long term integrity implies establishing calibration sites with enhanced ground based methods for <span class="hlt">sea</span> <span class="hlt">level</span> monitoring. A technical Spanish contribution to the calibration experience has been the design of GPS buoys and GPS catamaran taking in account the University of Colorado at Boulder and Senetosa/Capraia designs. Altimeter calibration is essential to obtain an absolute measure of <span class="hlt">sea</span> <span class="hlt">level</span>, as are knowing the instrument's drifts and bias. Specially designed tidegauges are necessary to improve the quality of altimetric data, preferably near the satellite track. Further, due to systematic differences a month instruments onboard different satellites, several in-situ calibrations are essentials to tie their systematic differences. L'Estartit tide gauge is a classical floating tide gauge set up in l'Estartit harbour (NE Spain) in 1990. It provides good quality information about the changes in the <span class="hlt">sea</span> heights at centimetre <span class="hlt">level</span>, that is the magnitude of the common tides in theMediterranean. In the framework of a Spanish Space Project, ref:ESP2001- 4534-PE, the instrumentation of <span class="hlt">sea</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1413767Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1413767Y"><span id="translatedtitle">Preparing Coastal Parks for Future <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Young, R.; Peek, K.</p> <p>2012-04-01</p> <p>The United States National Park Service (NPS) manages significant stretches of shoreline along the U.S. Atlantic, Pacific, and Gulf Coasts that are vulnerable to long-term <span class="hlt">sea</span> <span class="hlt">level</span> rise, shoreline erosion, and storm impacts. These parks have a wide variety of missions— protecting some of the nation's most important natural and cultural resources. The parks must also provide visitor access and education requiring infrastructure such as roads, visitor centers, trails, and buildings for facilities management. Planning for the likely impacts from <span class="hlt">sea</span> <span class="hlt">level</span> rise to both resources and infrastructure is a complex balancing act. Using coastal engineering to protect cultural resources or infrastructure may harm natural resources. At the same time, there are clearly some cultural and historical resources that are so critical that they must be protected. In an attempt to begin to attack this dilemma, the NPS Climate Change Response Program has initiated a <span class="hlt">sea</span> <span class="hlt">level</span> rise adaptation study that will provide a first-order tally of the park assets at risk to <span class="hlt">sea</span> <span class="hlt">level</span> rise and to begin to develop a plan for prioritizing those assets that must be protected, those that can be moved or abandoned, and an examination of how best to approach this without harming critical natural resources. This presentation will discuss the preliminary results of this effort along with several relevant case studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5112891','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5112891"><span id="translatedtitle">Fluctuating Mesozoic and Cenozoic <span class="hlt">sea</span> <span class="hlt">levels</span> and implications for stratigraphy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Haq, B.U. )</p> <p>1988-12-01</p> <p>Sequence stratigraphy encompasses depositional models of genetically related packages of sediments deposited during various phases of cycle of <span class="hlt">sea</span> <span class="hlt">level</span> change, i.e., from a lowstand to highstand to the subsequent lowstand. The application of these models to marine outcrops around the world and to subsurface data led to the construction of Mesozoic-Cenozoic <span class="hlt">sea</span> <span class="hlt">level</span> curves with greater event resolution than the earlier curves based on seismic data alone. Construction of these better resolution curves begins with an outline of the principles of sequence-stratigraphic analysis and the reconstruction of the history of <span class="hlt">sea</span> <span class="hlt">level</span> change from outcrop and subsurface data for the past 250 Ma. Examples of marine sections from North America, Europe, and Asia can be used to illustrate sequence analysis of outcrop data and the integration of chronostratigraphy with <span class="hlt">sea</span> <span class="hlt">level</span> history. Also important are the implications of sequence-stratigraphic methodology and the new cycle charts to various disciplines of stratigraphy, environmental reconstruction, and basin analysis. The relationship of unconformities along the continental margins to hiatuses and dissolution surfaces in the deep basins must also be explored, as well as the relevance of sequence-stratigraphic methodology to biofacies and source rock prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5412S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5412S"><span id="translatedtitle">Anomalous secular <span class="hlt">sea-level</span> acceleration in the Baltic <span class="hlt">Sea</span> caused by glacial isostatic adjustment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spada, Giorgio; Galassi, Gaia; Olivieri, Marco</p> <p>2014-05-01</p> <p>Observations from the global array of tide gauges show that global <span class="hlt">sea-level</span> has been rising at an average rate of 1.5-2 mm/yr during the last ˜ 150 years (Spada & Galassi, 2012). Although a global <span class="hlt">sea-level</span> acceleration was initially ruled out, subsequent studies have coherently proposed values of ˜1 mm/year/century (Olivieri & Spada, 2012). More complex non-linear trends and abrupt <span class="hlt">sea-level</span> variations have now also been recognized. Globally, they could manifest a regime shift between the late Holocene and the current rhythms of <span class="hlt">sea-level</span> rise, while locally they result from ocean circulation anomalies, steric effects and wind stress (Bromirski et al. 2011). Although isostatic readjustment affects the local rates of secular <span class="hlt">sea-level</span> change, a possible impact on regional acceleration have been so far discounted (Woodworth et al., 2009) since the process evolves on a millennium scale. Here we report a previously unnoticed anomaly in the long-term <span class="hlt">sea-level</span> acceleration of the Baltic <span class="hlt">Sea</span> tide gauge records, and we explain it by the classical post-glacial rebound theory and numerical modeling of glacial isostasy. Contrary to previous assumptions, our findings demonstrate that isostatic compensation plays a role in the regional secular <span class="hlt">sea-level</span> acceleration. In response to glacial isostatic adjustment (GIA), tide gauge records located along the coasts of the Baltic <span class="hlt">Sea</span> exhibit a small - but significant - long-term <span class="hlt">sea-level</span> acceleration in excess to those in the far field of previously glaciated regions. The sign and the amplitude of the anomaly is consistent with the post-glacial rebound theory and with realistic numerical predictions of GIA models routinely employed to decontaminate the tide gauges observations from the GIA effects (Peltier, 2004). Model computations predict the existence of anomalies of similar amplitude in other regions of the globe where GIA is still particularly vigorous at present, but no long-term instrumental observations are available to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4447J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4447J"><span id="translatedtitle">Revisiting <span class="hlt">sea</span> <span class="hlt">level</span> changes in the North <span class="hlt">Sea</span> during the Anthropocene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jensen, Jürgen; Dangendorf, Sönke; Wahl, Thomas; Niehüser, Sebastian</p> <p>2016-04-01</p> <p>The North <span class="hlt">Sea</span> is one of the best instrumented ocean basins in the world. Here we revisit <span class="hlt">sea</span> <span class="hlt">level</span> changes in the North <span class="hlt">Sea</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> chapter of the North <span class="hlt">Sea</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> projections for the North <span class="hlt">Sea</span> coastlines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010OcDyn..60..883M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010OcDyn..60..883M"><span id="translatedtitle">Variability in Solomon <span class="hlt">Sea</span> circulation derived from altimeter <span class="hlt">sea</span> <span class="hlt">level</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Melet, Angélique; Gourdeau, Lionel; Verron, Jacques</p> <p>2010-08-01</p> <p>The Solomon <span class="hlt">Sea</span> is a key region in the Pacific Ocean where equatorial and subtropical circulations are connected. The region exhibits the highest <span class="hlt">levels</span> in <span class="hlt">sea</span> <span class="hlt">level</span> variability in the entire south tropical Pacific Ocean. Altimeter data was utilized to explore <span class="hlt">sea</span> <span class="hlt">level</span> and western boundary currents in this poorly understood portion of the ocean. Since the geography of the region is extremely intricate, with numerous islands and complex bathymetry, specifically reprocessed along-track data in addition to standard gridded data were utilized in this study. <span class="hlt">Sea</span> <span class="hlt">level</span> anomalies (SLA) in the Solomon <span class="hlt">Sea</span> principally evolve at seasonal and interannual time scales. The annual cycle is phased by Rossby waves arriving in the Solomon Strait, whereas the interannual signature corresponds to the basin-scale ENSO mode. The highest SLA variability are concentrated in the eastern Solomon <span class="hlt">Sea</span>, particularly at the mouth of the Solomon Strait, where they are associated with a high eddy kinetic energy signal that was particularly active during the phase transition during the 1997-1998 ENSO event. Track data appear especially helpful for documenting the fine structure of surface coastal currents. The annual variability of the boundary currents that emerged from altimetry compared quite well with the variability seen at the thermocline <span class="hlt">level</span>, as based on numerical simulations. At interannual time scales, western boundary current transport anomalies counterbalance changes in western equatorial Pacific warm water volume, confirming the phasing of South Pacific western boundary currents to ENSO. Altimetry appears to be a valuable source of information for variability in low latitude western boundary currents and their associated transport in the South Pacific.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1812016S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1812016S"><span id="translatedtitle">Uncertainty estimates of altimetric Global Mean <span class="hlt">Sea</span> <span class="hlt">Level</span> timeseries</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scharffenberg, Martin; Hemming, Michael; Stammer, Detlef</p> <p>2016-04-01</p> <p>An attempt is being presented concerned with providing uncertainty measures for global mean <span class="hlt">sea</span> <span class="hlt">level</span> time series. For this purpose <span class="hlt">sea</span> surface height (SSH) fields, simulated by the high resolution STORM/NCEP model for the period 1993 - 2010, were subsampled along altimeter tracks and processed similar to techniques used by five working groups to estimate GMSL. Results suggest that the spatial and temporal resolution have a substantial impact on GMSL estimates. Major impacts can especially result from the interpolation technique or the treatment of SSH outliers and easily lead to artificial temporal variability in the resulting time series.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.G31A0911V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.G31A0911V"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">Level</span> Variation at the North Atlantic Ocean from Altimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vigo, I.; Sanchez-Reales, J. M.; Belda, S.</p> <p>2012-12-01</p> <p>About twenty years of multi-satellite radar altimeter data are analyzed to investigate the <span class="hlt">sea-level</span> variation (SLV) of the North Atlantic Ocean. In particular seasonal variations and inter-seasonal trends are studied. <span class="hlt">Sea</span> surface temperature and ice mass lost variations at Greenland are investigated as potential contributors of SLV in the case. It was found a quadratic acceleration term to be significant at some areas mainly located at the sub-polar gyre region. Results are consistent with changes in temperature data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6577148','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6577148"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> during the Phanerozoic - what causes the fluctuations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Harrison, C.G.A.</p> <p>1985-01-01</p> <p>All possible causes of <span class="hlt">sea</span> <span class="hlt">level</span> change have been analyzed in order to explain the fall of <span class="hlt">sea</span> <span class="hlt">level</span> since the Cretaceous. The most important effect is the decrease in volume of the ridge crests due to an overall decrease in the rate of spreading since the Cretaceous. Other factors in order of decreasing importance are the reduction of the thermal bulge which accompanied the episode of Pacific volcanism between 110 and 70 my bp, the production of continental ice, the effect of the collision of India with Asia, and cooling of the ocean water. Sedimentation variation in the deep ocean has the effect of raising <span class="hlt">sea</span> <span class="hlt">level</span> a modest amount. The net variation in <span class="hlt">sea</span> <span class="hlt">level</span> during the past 80 million years has been a reduction by about 280 m after having allowed for isostatic adjustment of the ocean floor. This is considerably larger, than <span class="hlt">sea</span> <span class="hlt">level</span> calculated from the amount of continental flooding, and it is proposed that the discrepancy is due to a change in the continental hypsographic curve following the breakup of Pangea. This hypothesis is born out by studies of flooding during the Phanerozoic which reveal that flooding was very low at the beginning of the Mesozoic during a time of continental agglomeration, and high during much of the Paleozoic, which was a time of continental separation. In the Cambrian there is evidence for an increase in flooding with time, and at the beginning of the Cambrian flooding was not much greater than at the beginning of the Mesozoic, suggesting that it marked a time just subsequent to the break up of a super continent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70024231','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70024231"><span id="translatedtitle">Responses of coastal wetlands to rising <span class="hlt">sea</span> <span class="hlt">level</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Morris, J.T.; Sundareshwar, P.V.; Nietch, C.T.; Kjerfve, B.; Cahoon, D.R.</p> <p>2002-01-01</p> <p>Salt marsh ecosystems are maintained by the dominant macrophytes that regulate the elevation of their habitat within a narrow portion of the intertidal zone by accumulating organic matter and trapping inorganic sediment. The long-term stability of these ecosystems is explained by interactions among <span class="hlt">sea</span> <span class="hlt">level</span>, land elevation, primary production, and sediment accretion that regulate the elevation of the sediment surface toward an equilibrium with mean <span class="hlt">sea</span> <span class="hlt">level</span>. We show here in a salt marsh that this equilibrium is adjusted upward by increased production of the salt marsh macrophyte Spartina alterniflora and downward by an increasing rate of relative <span class="hlt">sea-level</span> rise (RSLR). Adjustments in marsh surface elevation are slow in comparison to interannual anomalies and long-period cycles of <span class="hlt">sea</span> <span class="hlt">level</span>, and this lag in sediment elevation results in significant variation in annual primary productivity. We describe a theoretical model that predicts that the system will be stable against changes in relative mean <span class="hlt">sea</span> <span class="hlt">level</span> when surface elevation is greater than what is optimal for primary production. When surface elevation is less than optimal, the system will be unstable. The model predicts that there is an optimal rate of RSLR at which the equilibrium elevation and depth of tidal flooding will be optimal for plant growth. However, the optimal rate of RSLR also represents an upper limit because at higher rates of RSLR the plant community cannot sustain an elevation that is within its range of tolerance. For estuaries with high sediment loading, such as those on the southeast coast of the United States, the limiting rate of RSLR was predicted to be at most 1.2 cm/yr, which is 3.5 times greater than the current, long-term rate of RSLR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.U22A..03C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.U22A..03C"><span id="translatedtitle">Understanding and projecting <span class="hlt">sea</span> <span class="hlt">level</span> change: improvements and uncertainties (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Church, J. A.; Clark, P. U.; Cazenave, A. A.; Gregory, J. M.; Jevrejeva, S.; Merrifield, M. A.; Milne, G. A.; Nerem, R.; Payne, A. J.; Pfeffer, W. T.; Stammer, D.; Levermann, A.; Nunn, P.; Unnikrishnan, A. S.</p> <p>2013-12-01</p> <p>The rate of global mean <span class="hlt">sea</span> <span class="hlt">level</span> rise (GMSLR) has accelerated during the last two centuries, from a rate of order tenths of mm yr-1 during the late Holocene, to about 1.7 mm yr-1 since 1901. Ocean thermal expansion and glacier melting were the dominant contributors to 20th century GMSLR, with relatively small contributions from the Greenland and Antarctic ice sheets. Process-based models suggest that the larger rate of rise since 1990 results from increased radiative forcing (both natural and anthropogenic) and increased ice-sheet outflow, induced by warming of the immediately adjacent ocean. Confidence in projections of global mean <span class="hlt">sea</span> <span class="hlt">level</span> rise has increased since the AR4 because of improved physical process-based understanding of observed <span class="hlt">sea</span> <span class="hlt">level</span> change, especially in recent decades, and the inclusion of future rapid ice-sheet dynamical changes, for which a quantitative assessment could not be made on the basis of scientific knowledge available at the time of the AR4. By 2100, the rate of GMSLR for a scenario of high emissions (RCP8.5) could approach the average rates that occurred during the last deglaciation, whereas for a strong emissions mitigation scenario (RCP2.6) it could stabilise at rates similar to those of the early 21st century. In either case, GMSLR will continue for many subsequent centuries. Although there has been much recent progress, projections of ice-sheet change are still uncertain, especially beyond 2100. Future <span class="hlt">sea</span> <span class="hlt">level</span> change will not be globally uniform, but models still exhibit substantial disagreement in projections of ice mass loss and ocean dynamics, which are the main influences on the pattern. Uncertainty in projections of future storminess is a further obstacle to confident projection of changes in <span class="hlt">sea</span> <span class="hlt">level</span> extremes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS33C1084P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS33C1084P"><span id="translatedtitle">Pacific <span class="hlt">Sea</span> <span class="hlt">Level</span> Rise Pattern and Global Warming Hiatus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peyser, C.; Yin, J.; Landerer, F. W.</p> <p>2014-12-01</p> <p>Two important topics in current climate research are the global warming hiatus and the seesaw pattern of <span class="hlt">sea</span> <span class="hlt">level</span> rise (SLR) in the Pacific Ocean. We use ocean temperature and <span class="hlt">sea-level</span> observations along with CMIP5 climate modelling data to investigate the relationship between the warming hiatus and <span class="hlt">sea-level</span> variability in the Pacific Ocean. We analyse ocean heat content (OHC) trend by basin and layer for the full record (1945-2012) as well as the hiatus period (1998-2012). The result confirms the importance of the Pacific for heat uptake during the hiatus. Notably, the subsurface layer of the Pacific shows significant increase in OHC during the hiatus and a strong east-west compensation. This is mainly responsible for and reflected by the seesaw pattern of the Pacific <span class="hlt">sea</span> <span class="hlt">level</span> through thermosteric effect. The control simulations from 38 CMIP5 models indicate that the seesaw pattern of SLR in the Pacific is mainly a feature of decadal to multidecadal variability. Most CMIP5 models can capture this variability, especially in the Pacific Decadal Oscillation region (poleward of 20°N). The CMIP5 control runs show that during periods of negative trends of global temperatures (analogous to hiatus decades in a warming world), <span class="hlt">sea</span> <span class="hlt">level</span> increases in the western Pacific and decreases in the eastern Pacific. The opposite is true during periods of positive temperature trend (accelerated warming). These results suggest that a possible flip of the Pacific SLR seesaw would imply a resumption of surface warming and a SLR acceleration along the U.S. West Coast.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25629092','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25629092"><span id="translatedtitle">Probabilistic reanalysis of twentieth-century <span class="hlt">sea-level</span> rise.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hay, Carling C; Morrow, Eric; Kopp, Robert E; Mitrovica, Jerry X</p> <p>2015-01-22</p> <p>Estimating and accounting for twentieth-century global mean <span class="hlt">sea</span> <span class="hlt">level</span> (GMSL) rise is critical to characterizing current and future human-induced <span class="hlt">sea-level</span> 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 <span class="hlt">sea-level</span> 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 <span class="hlt">sea-level</span> 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 <span class="hlt">sea-level</span> rise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26062511','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26062511"><span id="translatedtitle">Bipolar seesaw control on last interglacial <span class="hlt">sea</span> <span class="hlt">level</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marino, G; Rohling, E J; Rodríguez-Sanz, L; Grant, K M; Heslop, D; Roberts, A P; Stanford, J D; Yu, J</p> <p>2015-06-11</p> <p>Our current understanding of ocean-atmosphere-cryosphere interactions at ice-age terminations relies largely on assessments of the most recent (last) glacial-interglacial transition, Termination I (T-I). But the extent to which T-I is representative of previous terminations remains unclear. Testing the consistency of termination processes requires comparison of time series of critical climate parameters with detailed absolute and relative age control. However, such age control has been lacking for even the penultimate glacial termination (T-II), which culminated in a <span class="hlt">sea-level</span> highstand during the last interglacial period that was several metres above present. Here we show that Heinrich Stadial 11 (HS11), a prominent North Atlantic cold episode, occurred between 135 ± 1 and 130 ± 2 thousand years ago and was linked with rapid <span class="hlt">sea-level</span> rise during T-II. Our conclusions are based on new and existing data for T-II and the last interglacial that we collate onto a single, radiometrically constrained chronology. The HS11 cold episode punctuated T-II and coincided directly with a major deglacial meltwater pulse, which predominantly entered the North Atlantic Ocean and accounted for about 70 per cent of the glacial-interglacial <span class="hlt">sea-level</span> rise. We conclude that, possibly in response to stronger insolation and CO2 forcing earlier in T-II, the relationship between climate and ice-volume changes differed fundamentally from that of T-I. In T-I, the major <span class="hlt">sea-level</span> rise clearly post-dates Heinrich Stadial 1. We also find that HS11 coincided with sustained Antarctic warming, probably through a bipolar seesaw temperature response, and propose that this heat gain at high southern latitudes promoted Antarctic ice-sheet melting that fuelled the last interglacial <span class="hlt">sea-level</span> peak.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70019532','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70019532"><span id="translatedtitle">New allocyclic dimensions in a prograding carbonate bank: Evidence for <span class="hlt">eustatic</span>, tectonic, and paleoceanographic control (late Neogene, Bahamas)</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lidz, B.H.; McNeill, D.F.</p> <p>1997-01-01</p> <p>The deep-<span class="hlt">sea</span> record, examined recently for the first time in a shallow-depocenter setting, has unveiled remarkable evidence for new sedimentary components and allocyclic complexity in a large, well-studied carbonate bank, the western Great Bahama Bank. The evidence is a composite foraminiferal signature - Paleocene to early Miocene (allogenic or reworked) and late Miocene to late Pliocene (host) planktic taxa, and redeposited middle Miocene shallow benthic faunas. Ages of the oldest and youngest planktic groups range from ??? 66 to ??? 2 Ma. The reworked and redeposited taxa are a proxy for significant sediment components that otherwise have no lithofacies or seismic resolution. The composite signature, reinforced by a distinctive distribution of the reworked and redeposited faunas, documents a much more complex late Neogene depositional system than previously known. The system is more than progradational. The source sequences that supplied the constituent bank-margin grains formed at different water depths and over hundreds of kilometers and tens of millions of years apart. New evidence from the literature and from data obtained during Ocean Drilling Program (OOP) Leg 166 in the Santaren Channel (Bahamas) support early interpretations based on the composite fossil record and provide valuable new dimensions to regional allocyclicity. The middle Miocene taxa were confined to the lower part of the section by the latest Miocene-earliest Pliocene(?) lowstand of <span class="hlt">sea</span> <span class="hlt">level</span>. An orderly occurrence of the allogenic taxa is unique to the global reworked geologic record and appears to have been controlled by a combination of Paleogene-early Neogene tectonics at the source, <span class="hlt">eustatic</span> changes, and late Neogene current activity at the source and across the bank. The allogenic taxa expand the spatial and temporal range of information in the northern Bahamas by nearly an order of magnitude. In essence, some of the major processes active in the region during ??? 64 m.y. of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeCar..34..109J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeCar..34..109J"><span id="translatedtitle">Geoid Profiles in the Baltic <span class="hlt">Sea</span> Determined Using GPS and <span class="hlt">Sea</span> <span class="hlt">Level</span> Surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jürgenson, Harli; Liibusk, Aive; Ellmann, Artu</p> <p>2008-12-01</p> <p>The idea was to compare the geoid of <span class="hlt">sea</span> areas by an independent method, like GPS <span class="hlt">levelling</span>, on the mainland. On the earth surface we can compare the gravimetric geoid with GPS <span class="hlt">levelling</span> to get an accuracy estimation and tilt information. On the <span class="hlt">sea</span> we can do it by the GPS methodology and eliminating the current water tilt corrections and the <span class="hlt">sea</span> surface topography effect. A modern GPS device on board a ferry can store data every second and determine heights with an accuracy of a few centimetres (using the kinematic method with the postprocessing of data obtained from several base stations close to the ferry line). As a result, it is possible to observe the current water <span class="hlt">level</span>'s relative profile in reference to the ellipsoid. Some areas close to Estonia, such as the eastern part of the Gulf of Finland, are not completely covered by gravity measurements. The Baltic <span class="hlt">Sea</span> has been measured using airborne gravimetry with the accuracy of about 2 mGal. Therefore, the gravimetric geoid is not fully reliable for the region either. If we take into account the tilt of the water <span class="hlt">level</span> at the moment of measurement, we can observe the relative change of the geoid using an independent methodology, which serves as a comparison to the gravimetric geoid solution. The main problem during the measurement campaign, of course, was how to eliminate a water tilt. Water placement in relation to <span class="hlt">level</span> surface is a very complex issue; special studies of that were conducted as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ClDy..tmp..367M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ClDy..tmp..367M"><span id="translatedtitle">Impact of accelerated future global mean <span class="hlt">sea</span> <span class="hlt">level</span> rise on hypoxia in the Baltic <span class="hlt">Sea</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meier, H. E. M.; Höglund, A.; Eilola, K.; Almroth-Rosell, E.</p> <p>2016-08-01</p> <p>Expanding hypoxia is today a major threat for many coastal <span class="hlt">seas</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> rise (GSLR) upon water exchange and oxygen conditions in a semi-enclosed, shallow <span class="hlt">sea</span>. As a study site, the Baltic <span class="hlt">Sea</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span>, 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 <span class="hlt">Sea</span> and other coastal <span class="hlt">seas</span> 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.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.457..325W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.457..325W"><span id="translatedtitle">Speleothem evidence for MIS 5c and 5a <span class="hlt">sea</span> <span class="hlt">level</span> above modern <span class="hlt">level</span> at Bermuda</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wainer, Karine A. I.; Rowe, Mark P.; Thomas, Alexander L.; Mason, Andrew J.; Williams, Bruce; Tamisiea, Mark E.; Williams, Felicity H.; Düsterhus, André; Henderson, Gideon M.</p> <p>2017-01-01</p> <p>The history of <span class="hlt">sea</span> <span class="hlt">level</span> in regions impacted by glacio-isostasy provides constraints on past ice-sheet distribution and on the characteristics of deformation of the planet in response to loading. The Western North Atlantic-Caribbean region, and Bermuda in particular, is strongly affected by the glacial forebulge that forms as a result of the Laurentide ice-sheet present during glacial periods. The timing of growth of speleothems, at elevations close to <span class="hlt">sea</span> <span class="hlt">level</span> can provide records of minimum relative <span class="hlt">sea</span> <span class="hlt">level</span> (RSL). In this study we used U-Th dating to precisely date growth periods of speleothems from Bermuda which were found close to modern-day <span class="hlt">sea</span> <span class="hlt">level</span>. Results suggest that RSL at this location was above modern during MIS5e, MIS5c and MIS5a. These data support controversial previous indications that Bermudian RSL was significantly higher than RSL at other locations during MIS 5c and MIS 5a. We confirm that it is possible to explain a wide range of MIS5c-a relative <span class="hlt">sea</span> <span class="hlt">levels</span> observed across the Western North Atlantic-Caribbean in glacial isostatic adjustment models, but only with a limited range of mantle deformation constants. This study demonstrates the particular power of Bermuda as a gauge for response of the forebulge to glacial loading, and demonstrates the potential for highstands at this location to be significantly higher than in other regions, helping to explain the high <span class="hlt">sea</span> <span class="hlt">levels</span> observed for Bermuda from earlier highstands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.6327T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.6327T"><span id="translatedtitle">Investigating the influence of <span class="hlt">sea</span> <span class="hlt">level</span> oscillations in the Danish Straits on the Baltic <span class="hlt">Sea</span> dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tikhonova, Natalia; Gusev, Anatoly; Diansky, Nikolay; Zakharchuk, Evgeny</p> <p>2016-04-01</p> <p> related to the distance between the measurement point and open boundary. For example, in the Gulfs of Finland and Riga, the 36hr harmonic has an amplitude substantially higher than in the open <span class="hlt">sea</span>, and in the Stockholm area, this harmonic is at the noise <span class="hlt">level</span>. The 40dy and 121dy harmonics have slightly lower amplitudes than the original prescribed signal, but they are almost unchanged while propagating further into the <span class="hlt">sea</span>, and in all the investigated locations have almost identical peaks of spectral density. The 3dy and 6dy harmonics significantly lost their amplitude in all parts of the <span class="hlt">sea</span>, and spectral density peaks are at the noise <span class="hlt">level</span>. The simulation results showed us that the Danish straits do not filter 121dy and 40dy oscillations, and their amplitude does not decrease much. The 13dy, 6dy and 3dy oscillations significantly lose in amplitude and have no significant peaks of the spectral density. The 1.5dy harmonic propagates to the Gulfs of Finland and Riga, and increases in amplitude due to resonance at the natural frequency of the basin. It is suggested that, while Danish straits do not filter or transform frequency characteristics of oscillations propagated from the North <span class="hlt">Sea</span>, but the Baltic <span class="hlt">Sea</span> configuration may affect the magnitude and propagation extent of these oscillations. Thus, the fluctuations in the North <span class="hlt">Sea</span> and the Danish Straits can significantly contribute to the Baltic <span class="hlt">Sea</span> dynamics in the low-frequency range of the spectrum, and the periods of natural oscillations of the basin. The research was supported by the Russian Foundation for Basic Research (grant № 16-05-00534) and Saint-Petersburg State University (grant №18.37.140.2014)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24739960','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24739960"><span id="translatedtitle"><span class="hlt">Sea-level</span> and deep-<span class="hlt">sea</span>-temperature variability over the past 5.3 million years.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rohling, E J; Foster, G L; Grant, K M; Marino, G; Roberts, A P; Tamisiea, M E; Williams, F</p> <p>2014-04-24</p> <p>Ice volume (and hence <span class="hlt">sea</span> <span class="hlt">level</span>) and deep-<span class="hlt">sea</span> temperature are key measures of global climate change. <span class="hlt">Sea</span> <span class="hlt">level</span> has been documented using several independent methods over the past 0.5 million years (Myr). Older periods, however, lack such independent validation; all existing records are related to deep-<span class="hlt">sea</span> oxygen isotope (δ(18)O) data that are influenced by processes unrelated to <span class="hlt">sea</span> <span class="hlt">level</span>. For deep-<span class="hlt">sea</span> temperature, only one continuous high-resolution (Mg/Ca-based) record exists, with related <span class="hlt">sea-level</span> estimates, spanning the past 1.5 Myr. Here we present a novel <span class="hlt">sea-level</span> reconstruction, with associated estimates of deep-<span class="hlt">sea</span> temperature, which independently validates the previous 0-1.5 Myr reconstruction and extends it back to 5.3 Myr ago. We find that deep-<span class="hlt">sea</span> temperature and <span class="hlt">sea</span> <span class="hlt">level</span> generally decreased through time, but distinctly out of synchrony, which is remarkable given the importance of ice-albedo feedbacks on the radiative forcing of climate. In particular, we observe a large temporal offset during the onset of Plio-Pleistocene ice ages, between a marked cooling step at 2.73 Myr ago and the first major glaciation at 2.15 Myr ago. Last, we tentatively infer that ice sheets may have grown largest during glacials with more modest reductions in deep-<span class="hlt">sea</span> temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7423M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7423M"><span id="translatedtitle">Geodetic infrastructure at the Barcelona harbour for <span class="hlt">sea</span> <span class="hlt">level</span> monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martinez-Benjamin, Juan Jose; Gili, Josep; Lopez, Rogelio; Tapia, Ana; Pros, Francesc; Palau, Vicenc; Perez, Begona</p> <p>2015-04-01</p> <p>The presentation is directed to the description of the actual geodetic infrastructure of Barcelona harbour with three tide gauges of different technologies for <span class="hlt">sea</span> <span class="hlt">level</span> determination and contribution to regional <span class="hlt">sea</span> <span class="hlt">level</span> rise and understanding past and present <span class="hlt">sea</span> <span class="hlt">level</span> rise in the Barcelona harbour. It is intended that the overall system will constitute a CGPS Station of the ESEAS (European <span class="hlt">Sea</span> <span class="hlt">Level</span>) and TIGA (GPS Tide Gauge Benchmark Monitoring) networks. At Barcelona harbour there is a MIROS radar tide gauge belonging to Puertos del Estado (Spanish Harbours).The radar sensor is over the water surface, on a L-shaped structure which elevates it a few meters above the quay shelf. 1-min data are transmitted to the ENAGAS Control Center by cable and then sent each 1 min to Puertos del Estado by e-mail. The information includes wave forescast (mean period, significant wave height, <span class="hlt">sea</span> <span class="hlt">level</span>, etc.This sensor also measures agitation and sends wave parameters each 20 min. There is a GPS station Leica Geosystems GRX1200 GG Pro and antenna AX 1202 GG. The Control Tower of the Port of Barcelona is situated in the North dike of the so-called Energy Pier in the Barcelona harbor (Spain). This tower has different kind of antennas for navigation monitoring and a GNSS permanent station. As the tower is founded in reclaimed land, and because its metallic structure, the 50 m building is subjected to diverse movements, including periodic fluctuations due to temperature changes. In this contribution the 2009, 2011, 2012, 2013 and 2014 the necessary monitoring campaigns are described. In the framework of a Spanish Space Project, the instrumentation of <span class="hlt">sea</span> <span class="hlt">level</span> measurements has been improved by providing the Barcelona site with a radar tide gauge Datamar 2000C from Geonica S.L. in June 2014 near an acoustic tide gauge from the Barcelona Harbour installed in 2013. Precision <span class="hlt">levelling</span> has been made several times in the last two years because the tower is founded in reclaimed land and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1813674B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1813674B"><span id="translatedtitle">Estimating geocenter motion and barystatic <span class="hlt">sea-level</span> variability from GRACE observations with explicit consideration of self-attraction and loading effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bergmann-Wolf, Inga; Dobslaw, Henryk</p> <p>2016-04-01</p> <p>Estimating global barystatic <span class="hlt">sea-level</span> variations from monthly mean gravity fields delivered by the Gravity Recovery and Climate Experiment (GRACE) satellite mission requires additional information about geocenter motion. These variations are not available directly due to the mission implementation in the CM-frame and are represented by the degree-1 terms of the spherical harmonics expansion. Global degree-1 estimates can be determined with the method of Swenson et al. (2008) from ocean mass variability, the geometry of the global land-<span class="hlt">sea</span> distribution, and GRACE data of higher degrees and orders. Consequently, a recursive relation between the derivation of ocean mass variations from GRACE data and the introduction of geocenter motion into GRACE data exists. In this contribution, we will present a recent improvement to the processing strategy described in Bergmann-Wolf et al. (2014) by introducing a non-homogeneous distribution of global ocean mass variations in the geocenter motion determination strategy, which is due to the effects of loading and self-attraction induced by mass redistributions at the surface. A comparison of different GRACE-based oceanographic products (barystatic signal for both the global oceans and individual basins; barotropic transport variations of major ocean currents) with degree-1 terms estimated with a homogeneous and non-homogeneous ocean mass representation will be discussed, and differences in noise <span class="hlt">levels</span> in most recent GRACE solutions from GFZ (RL05a), CSR, and JPL (both RL05) and their consequences for the application of this method will be discussed. Swenson, S., D. Chambers and J. Wahr (2008), Estimating geocenter variations from a combination of GRACE and ocean model output, J. Geophys. Res., 113, B08410 Bergmann-Wolf, I., L. Zhang and H. Dobslaw (2014), Global <span class="hlt">Eustatic</span> <span class="hlt">Sea-Level</span> Variations for the Approximation of Geocenter Motion from GRACE, J. Geod. Sci., 4, 37-48</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.438..139E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.438..139E"><span id="translatedtitle">Planktic foraminifera shell chemistry response to seawater chemistry: Pliocene-Pleistocene seawater Mg/Ca, temperature and <span class="hlt">sea</span> <span class="hlt">level</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Evans, David; Brierley, Chris; Raymo, Maureen E.; Erez, Jonathan; Müller, Wolfgang</p> <p>2016-03-01</p> <p>Foraminifera Mg/Ca paleothermometry forms the basis of a substantial portion of ocean temperature reconstruction over the last 5 Ma. Furthermore, coupled Mg/Ca-oxygen isotope (δ18O) measurements of benthic foraminifera can constrain <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> (ESL) independent of paleo-shoreline derived approaches. However, this technique suffers from uncertainty regarding the secular variation of the Mg/Ca seawater ratio (Mg/Casw) on timescales of millions of years. Here we present coupled seawater-test Mg/Ca-temperature laboratory calibrations of Globigerinoides ruber in order to test the widely held assumptions that (1) seawater-test Mg/Ca co-vary linearly, and (2) the Mg/Ca-temperature sensitivity remains constant with changing Mg/Casw. We find a nonlinear Mg/Catest-Mg/Casw relationship and a lowering of the Mg/Ca-temperature sensitivity at lower than modern Mg/Casw from 9.0% °C-1 at Mg/Casw = 5.2 mol mol-1 to 7.5 ± 0.9% °C-1 at 3.4 mol mol-1. Using our calibrations to more accurately calculate the offset between Mg/Ca and biomarker-derived paleotemperatures for four sites, we derive a Pliocene Mg/Casw ratio of ∼4.3 mol mol-1. This Mg/Casw implies Pliocene ocean temperature 0.9-1.9 °C higher than previously reported and, by extension, ESL ∼30 m lower compared to when one assumes that Pliocene Mg/Casw is the same as at present. Correcting existing benthic foraminifera datasets for Mg/Casw indicates that deep water source composition must have changed through time, therefore seawater oxygen isotope reconstructions relative to present day cannot be used to directly reconstruct Pliocene ESL.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020741','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020741"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> controls on the textural characteristics and depositional architecture of the Hueneme and associated submarine fan systems, Santa Monica Basin, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Normark, W.R.; Piper, D.J.W.; Hiscott, R.N.</p> <p>1998-01-01</p> <p>Hueneme and Dume submarine fans in Santa Monica Basin consist of sandy channel and muddy levee facies on the upper fan. lenticular sand sheets on the middle fan. and thinly bedded turbidite and hemipelagic facies elsewhere. Fifteen widely correlatable key seismic reflections in high-resolution airgun and deep-towed boomer profiles subdivide the fan and basin deposits into time-slices that show different thickness and seismic-facies distributions, inferred to result from changes in Quaternary <span class="hlt">sea</span> <span class="hlt">level</span> and sediment supply. At times of low <span class="hlt">sea</span> <span class="hlt">level</span>, highly efficient turbidity currents generated by hyperpycnal flows or sediment failures at river deltas carry sand well out onto the middle-fan area. Thick, muddy flows formed rapidly prograding high levees mainly on the western (right-hand) side of three valleys that fed Hueneme fan at different times: the most recently active of the lowstand fan valleys. Hueneme fan valley, now heads in Hueneme Canyon. At times of high <span class="hlt">sea</span> <span class="hlt">level</span>, fans receive sand from submarine canyons that intercept littoral-drift cells and mixed sediment from earthquake-triggered slumps. Turbidity currents are confined to 'underfit' talweg channels in fan valleys and to steep, small, basin-margin fans like Dume fan. Mud is effectively separated from sand at high <span class="hlt">sea</span> <span class="hlt">level</span> and moves basinward across the shelf in plumes and in storm-generated lutite flows, contributing to a basin-floor blanket that is locally thicker than contemporary fan deposits and that onlaps older fans at the basin margin. The infilling of Santa Monica Basin has involved both fan and basin-floor aggradation accompanied by landward and basinward facies shifts. Progradation was restricted to the downslope growth of high muddy levees and the periodic basinward advance of the toe of the steeper and sandier Dume fan. Although the region is tectonically active, major sedimentation changes can be related to <span class="hlt">eustatic</span> <span class="hlt">sea-level</span> changes. The primary controls on facies shifts and fan growth</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5531B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5531B"><span id="translatedtitle">Using a Glacial Isostatic Adjustment model to investigate the contribution of the Antarctic and Greenland Ice sheet to the Last Interglacial <span class="hlt">Sea</span> <span class="hlt">Level</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bradley, Sarah; Hindmarsh, Richard C. A.</p> <p>2014-05-01</p> <p><span class="hlt">Eustatic</span> <span class="hlt">Sea</span> <span class="hlt">Level</span> during the Last interglacial (LIG) is likely to have been 4- 6 m higher than present day, with the observed relative <span class="hlt">sea</span> <span class="hlt">level</span> (RSL) at numerous far-field sites even higher [Dutton and Lambeck, 2012]. It has been suggested to generate this higher than present day <span class="hlt">sea</span> <span class="hlt">level</span> requires a retreat of both the Antarctic (AIS) and Greenland (GIS) Ice sheets beyond the present day extent, but the exact contribution of these two global ice sheets has yet to be resolved. By combing a Glacial Isostatic Adjustment (GIA) model with a suite of LIG ice-loading histories we will address a number of outstanding issues (i) What was the contribution of the AIS and GIS to ESL, (ii) Was the AIS or the GIS smaller during the LIG than the present interglacial? (iii) Can we generate the observed higher LIG RSL at a range of far-field sites? The suite of AIS and GIS ice-loading histories is constrained using the most recent near-field evidence, LIG stable isotope ice core data [Dahl-Jensen et al., 2013; Masson-Delmotte et al., 2011] and the output from ice sheet and climate models [Helsen et al., 2013; Pollard and DeConto, 2009; Stone et al., 2013]. Comparing the predicted RSL to a recent database of observed LIG far-field <span class="hlt">sea</span> <span class="hlt">level</span> [Dutton and Lambeck, 2012] allows for an assessment of the plausibility of the suite of ice loading histories. With this study, we aim to provide insight into the LIG history of the AIS and GIS. Dahl-Jensen, D., et al. (2013), Eemian interglacial reconstructed from a Greenland folded ice core, Nature, 493(7433), 489-494. Dutton, A., and K. Lambeck (2012), Ice Volume and <span class="hlt">Sea</span> <span class="hlt">Level</span> During the Last Interglacial, Science, 337(6091), 216-219. Helsen, M. M., W. J. van de Berg, R. S. W. van de Wal, M. R. van den Broeke, and J. Oerlemans (2013), Coupled regional climate-ice-sheet simulation shows limited Greenland ice loss during the Eemian, Clim Past, 9(4), 1773-1788. Masson-Delmotte, V., et al. (2011), A comparison of the present and last</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016QSRv..137...54B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016QSRv..137...54B"><span id="translatedtitle">Modelling <span class="hlt">sea</span> <span class="hlt">level</span> data from China and Malay-Thailand to estimate Holocene ice-volume equivalent <span class="hlt">sea</span> <span class="hlt">level</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bradley, Sarah L.; Milne, Glenn A.; Horton, Benjamin P.; Zong, Yongqiang</p> <p>2016-04-01</p> <p>This study presents a new model of Holocene ice-volume equivalent <span class="hlt">sea</span> <span class="hlt">level</span> (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 <span class="hlt">sea</span> <span class="hlt">level</span> (RSL) predictions from a glacial isostatic adjustment (GIA) model to a suite of Holocene <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span>, the timing of this maximum, and the temporal variation of <span class="hlt">sea</span> <span class="hlt">level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19900033471&hterms=Barometers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBarometers','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19900033471&hterms=Barometers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBarometers"><span id="translatedtitle">Seasonal variability in global <span class="hlt">sea</span> <span class="hlt">level</span> observed with Geosat altimetry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zlotnicki, V.; Fu, L.-L.; Patzert, W.</p> <p>1989-01-01</p> <p>Time changes in global mesoscale <span class="hlt">sea</span> <span class="hlt">level</span> variances were observed with satellite altimetry between November 1986 and March 1988, showing significant, geographically coherent seasonal patterns. The NE Pacific and NE Atlantic variances show the most reliable patterns, higher than their yearly averages in both the fall and winter. The response to wind forcing appears as the major contributor to the NE Pacific and Atlantic signals; errors in the estimated inverse barometer response due to errors in atmospheric pressure, residual orbit errors, and errors in <span class="hlt">sea</span> state bias are evaluated and found to be negligible contributors to this particular signal. The equatorial regions also show significant seasonal patterns, but the uncertainties in the wet tropospheric correction prevent definitive conclusions. The western boundary current changes are very large but not statistically significant. Estimates of the regression coefficient between <span class="hlt">sea</span> <span class="hlt">level</span> and significant wave height, an estimate of the <span class="hlt">sea</span> state bias correction, range between 2.3 and 2.9 percent and vary with the type of orbit correction applied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....8435A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....8435A"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> during roman epoch in the central Tyrrhenian <span class="hlt">sea</span> (Italy)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anzidei, M.; Antonioli, F.; Benini, A.; Esposito, A.; Lambeck, K.; Surace, L.</p> <p>2003-04-01</p> <p>The aim of this research is to reconstruct the vertical deformations of the earth's crust and the relative <span class="hlt">sea</span> <span class="hlt">level</span> oscillations during late Holocene (2-3 ka BP) by means of multidisciplinary investigations of archaeological sites located along the central Tyrrhenian coastlines (Italy). The sites (piscinae, harbours and quarries) of pre-Roman and Roman Age, play a fundamental role for the evaluation of the <span class="hlt">sea</span> <span class="hlt">level</span> rise during the last 2.5 ka. Early studies using this technique were performed by Flemming (1969), Schmiedt (1972), Pirazzoli (1976) and more recently by Flemming and Webb (1986) and Leoni and Dai Pra (1997). We have used the original latin sources written by the historical Roman authors Varrone and Columella to understand the detailed technical rules for the construction of the piscinae (depth of ponds and channels, operating range of the sluice gates, etc.). On the basis of these publications we re-interpret some significant sites to estimate the difference between their ancient depths and some recent interpretations. We studied the remains located at Castiglioncello, Gravisca, Punta della Vipera, Santa Marinella, Torre Astura and Ventotene island. Our data show an increase in <span class="hlt">sea</span> <span class="hlt">level</span> at these sites of between 178±20 and 125±20 cm since pre-roman age (2.3-1.9 ka BP). All sites are located along about 400 km coastline of the Tyrrhenian <span class="hlt">sea</span>, from Tuscany to Latium, that exhibits areas of both tectonic stability and instability and we use the elevation of the MIS 5.5 transgression (inner margin sediments) to estimate the rates of uplift or subsidence. At Punta della Vipera this elevation reaches 35 m (Antonioli et al., 2000) and we consider that this area has been tectonically active with an uplift rate of 0.23 ± 0.05 mm yr-1. High resolution numerical models of <span class="hlt">sea-level</span> change have been used and tested against other Italian <span class="hlt">sea</span> <span class="hlt">level</span> data to provide a realistic representation of the spatial variability of the <span class="hlt">sea-level</span> change and shoreline</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006GeoRL..3314606Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006GeoRL..3314606Z"><span id="translatedtitle">Annual <span class="hlt">sea</span> <span class="hlt">level</span> amphidromes in the South China <span class="hlt">Sea</span> revealed by merged altimeter data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Caiyun; Wang, Bin; Chen, Ge</p> <p>2006-07-01</p> <p>Annual phase-amplitude characteristics of <span class="hlt">sea</span> <span class="hlt">level</span> anomaly (SLA) in the South China <span class="hlt">Sea</span> (SCS) are investigated by a merged SLA data set derived from simultaneous measurements of Envisat, Geosat-Follow-on (GFO), Jason-1, and TOPEX/Poseidon (T/P) from January 2004 to December 2005. Four annual amphidromes instead of two are revealed and their locations, surrounding the Vietnam eddy, distinguish two distinctive regimes of annual variations in the SCS, a basin scale monsoon regime and a local Vietnam eddy regime. Their existence suggests that the annual amphidrome is not only a common feature on global scale, but also a phenomenon in regional <span class="hlt">seas</span>. However, the locations of these amphidromes in the SCS vary considerably from year to year, in contrast to the annual amphidomes found in the tropical ocean basins, which are much more stable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017ChJOL..35...79Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017ChJOL..35...79Q"><span id="translatedtitle">Interannual to decadal variation of spring <span class="hlt">sea</span> <span class="hlt">level</span> anomaly in the western South China <span class="hlt">Sea</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qiu, Fuwen; Fang, Wendong; Pan, Aijun; Cha, Jing; Zhang, Shanwu; Huang, Jiang</p> <p>2017-01-01</p> <p>Satellite observations of <span class="hlt">sea</span> <span class="hlt">level</span> anomalies (SLA) from January 1993 to December 2012 are used to investigate the interannual to decadal changes of the boreal spring high SLA in the western South China <span class="hlt">Sea</span> (SCS) using the Empirical Orthogonal Function (EOF) method. We find that the SLA variability has two dominant modes. The <span class="hlt">Sea</span> <span class="hlt">Level</span> Changing Mode (SLCM) occurs mainly during La Niña years, with high SLA extension from west of Luzon to the eastern coast of Vietnam along the central basin of the SCS, and is likely induced by the increment of the ocean heat content. The Anticyclonic Eddy Mode (AEM) occurs mainly during El Niño years and appears to be triggered by the negative wind curl anomalies within the central SCS. In addition, the spring high SLA in the western SCS experienced a quasi-decadal change during 1993-2012; in other words, the AEM predominated during 1993-1998 and 2002-2005, while the La Niña-related SLCM prevailed during 1999-2001 and 2006-2012. Moreover, we suggest that the accelerated <span class="hlt">sea</span> <span class="hlt">level</span> rise in the SCS during 2005-2012 makes the SLCM the leading mode over the past two decades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70011660','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70011660"><span id="translatedtitle">Holocene changes in <span class="hlt">sea</span> <span class="hlt">level</span>: Evidence in Micronesia</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shepard, F.P.; Curray, Joseph R.; Newman, W.A.; Bloom, A.L.; Newell, N.D.; Tracey, J.I.; Veeh, H.H.</p> <p>1967-01-01</p> <p>Investigation of 33 islands, scattered widely across the Caroline and Marshall Island groups in the Central Pacific revealed no emerged reefs in which corals had unquestionably formed in situ, or other direct evidence of postglacial high stands of <span class="hlt">sea</span> <span class="hlt">level</span>. Low unconsolidated rock terraces and ridges of reef-flat islands, mostly lying between tide <span class="hlt">levels</span>, were composed of rubble conglomerates; carbon-14 dating of 11 samples from the conglomerates so far may suggest a former slightly higher <span class="hlt">sea</span> <span class="hlt">level</span> (nine samples range between 1890 and 3450 and one approaches 4500 years ago). However, recent hurricanes have produced ridges of comparable height and material, and in the same areas relics from World War II have been found cemented in place. Thus these datings do not in themselves necessarily indicate formerly higher <span class="hlt">sea</span> <span class="hlt">levels</span>. Rubble tracts are produced by storms under present conditions without any change in datum, and there seems to be no compelling evidence that they were not so developed during various periods in the past.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ERL.....4d1001H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ERL.....4d1001H"><span id="translatedtitle">PERSPECTIVE: The tripping points of <span class="hlt">sea</span> <span class="hlt">level</span> rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hecht, Alan D.</p> <p>2009-12-01</p> <p>When President Nixon created the US Environmental Protection Agency (EPA) in 1970 he said the environment must be perceived as a single, interrelated system. We are nowhere close to achieving this vision. Jim Titus and his colleagues [1] highlight one example of where one set of regulations or permits may be in conflict with another and where regulations were crafted in the absence of understanding the cumulative impact of global warming. The issue here is how to deal with the impacts of climate change on <span class="hlt">sea</span> <span class="hlt">level</span> and the latter's impact on wetland polices, clean water regulations, and ecosystem services. The Titus paper could also be called `The tripping points of <span class="hlt">sea</span> <span class="hlt">level</span> rise'. Titus and his colleagues have looked at the impact of such <span class="hlt">sea</span> <span class="hlt">level</span> rise on the east coast of the United States. Adaptive responses include costly large- scale investment in shore protection (e.g. dikes, sand replenishment) and/or ecosystem migration (retreat), where coastal ecosystems move inland. Shore protection is limited by available funds, while ecosystem migrations are limited by available land use. The driving factor is the high probability of <span class="hlt">sea</span> <span class="hlt">level</span> rise due to climate change. Estimating <span class="hlt">sea</span> <span class="hlt">level</span> rise is difficult because of local land and coastal dynamics including rising or falling land areas. It is estimated that <span class="hlt">sea</span> <span class="hlt">level</span> could rise between 8 inches and 2 feet by the end of this century [2]. The extensive data analysis done by Titus et al of current land use is important because, as they observe, `property owners and land use agencies have generally not decided how they will respond to <span class="hlt">sea</span> <span class="hlt">level</span> rise, nor have they prepared maps delineating where shore protection and retreat are likely'. This is the first of two `tripping points', namely the need for adaptive planning for a pending environmental challenge that will create economic and environment conflict among land owners, federal and state agencies, and businesses. One way to address this gap in adaptive management</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=oceans&pg=6&id=EJ920579','ERIC'); return false;" href="http://eric.ed.gov/?q=oceans&pg=6&id=EJ920579"><span id="translatedtitle">Flooded! An Investigation of <span class="hlt">Sea-Level</span> Rise in a Changing Climate</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Gillette, Brandon; Hamilton, Cheri</p> <p>2011-01-01</p> <p>Explore how melting ice sheets affect global <span class="hlt">sea</span> <span class="hlt">levels</span>. <span class="hlt">Sea-level</span> rise (SLR) is a rise in the water <span class="hlt">level</span> of the Earth's oceans. There are two major kinds of ice in the polar regions: <span class="hlt">sea</span> ice and land ice. Land ice contributes to SLR and <span class="hlt">sea</span> ice does not. This article explores the characteristics of <span class="hlt">sea</span> ice and land ice and provides some hands-on…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17801535','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17801535"><span id="translatedtitle">Milankovitch forcing of the last interglacial <span class="hlt">sea</span> <span class="hlt">level</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Crowley, T J; Kim, K Y</p> <p>1994-09-09</p> <p>During the last interglacial, <span class="hlt">sea</span> <span class="hlt">level</span> was as high as present, 4000 to 6000 years before peak Northern Hemisphere insolation receipt 126,000 years ago. The <span class="hlt">sea-level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999EOSTr..80..103G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999EOSTr..80..103G"><span id="translatedtitle">Holocene Antarctic's coastal environment, ice sheet, and <span class="hlt">sea</span> <span class="hlt">levels</span> explored</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goodwin, I.; Berkman, P.; Hjort, C.; Hirakawa, K.</p> <p></p> <p>Efforts are in the works to resolve a several-decade-long debate over the size and extent of the Antarctic ice sheet and its role in <span class="hlt">sea</span> <span class="hlt">levels</span> during the last glacial cycle. Researchers also want to find out more about the nature of environmental changes around the Antarctic coast throughout the Holocene, the sensitivity of the ice sheet to warm periods, and the significance of pre-Holocene marine fossils there.Scientists concerned with these issues presented their research priorities last fall at an Antarctic ice margin evolution (ANTIME) workshop, “Circum-Antarctic Coastal Environmental Variability and <span class="hlt">Sea</span> <span class="hlt">Level</span> History During the Late Quaternary.” These workshop participants included coastal and glacial geomorphologists, geochemists, and paleoecologists.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70013881','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70013881"><span id="translatedtitle">Contribution of small glaciers to global <span class="hlt">sea</span> <span class="hlt">level</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Meier, M.F.</p> <p>1984-01-01</p> <p>Observed long-term changes in glacier volume and hydrometeorological mass balance models yield data on the transfer of water from glaciers, excluding those in Greenland and Antarctica, to the oceans, The average observed volume change for the period 1900 to 1961 is scaled to a global average by use of the seasonal amplitude of the mass balance. These data are used to calibrate the models to estimate the changing contribution of glaciers to <span class="hlt">sea</span> <span class="hlt">level</span> for the period 1884 to 1975. Although the error band is large, these glaciers appear to accountfor a third to half of observed rise in <span class="hlt">sea</span> <span class="hlt">level</span>, approximately that fraction not explained by thermal expansion of the ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4978990','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4978990"><span id="translatedtitle">Is the detection of accelerated <span class="hlt">sea</span> <span class="hlt">level</span> rise imminent?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fasullo, J. T.; Nerem, R. S.; Hamlington, B.</p> <p>2016-01-01</p> <p>Global mean <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> 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. PMID:27506974</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=350421','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=350421"><span id="translatedtitle">Relative <span class="hlt">sea</span> <span class="hlt">levels</span> from tide-gauge records</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Emery, K. O.</p> <p>1980-01-01</p> <p>Mean annual <span class="hlt">sea</span> <span class="hlt">levels</span> at 247 tide-gauge stations of the world exhibit a general rise of relative <span class="hlt">sea</span> <span class="hlt">level</span> of about 3 mm/year during the past 40 years. In contrast, general uplift of the land is typical of high northern latitudes, where unloading of the crust by melt of Pleistocene ice sheets is significant. Erratic movements are typical of belts having crustal overthrusting and active volcanism. Short-term (5- and 10-year) records reveal recent changes in rates, but such short time spans may be so influenced by climatic cycles that identification of new trends is difficult, especially with the existing poor distribution and reporting of tide-gauge data. Images PMID:16592929</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GeoRL..41.4970R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeoRL..41.4970R"><span id="translatedtitle">Control of Quaternary <span class="hlt">sea-level</span> changes on gas seeps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riboulot, Vincent; Thomas, Yannick; Berné, Serge; Jouet, Gwénaël.; Cattaneo, Antonio</p> <p>2014-07-01</p> <p>Gas seeping to the seafloor through structures such as pockmarks may contribute significantly to the enrichment of atmospheric greenhouse gases and global warming. Gas seeps in the Gulf of Lions, Western Mediterranean, are cyclical, and pockmark "life" is governed both by sediment accumulation on the continental margin and Quaternary climate changes. Three-dimensional seismic data, correlated to multi-proxy analysis of a deep borehole, have shown that these pockmarks are associated with oblique chimneys. The prograding chimney geometry demonstrates the syn-sedimentary and long-lasting functioning of the gas seeps. Gas chimneys have reworked chronologically constrained stratigraphic units and have functioned episodically, with maximum activity around <span class="hlt">sea</span> <span class="hlt">level</span> lowstands. Therefore, we argue that one of the main driving mechanisms responsible for their formation is the variation in hydrostatic pressure driven by relative <span class="hlt">sea</span> <span class="hlt">level</span> changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6481137','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6481137"><span id="translatedtitle">Relative <span class="hlt">sea</span> <span class="hlt">levels</span> from tide-gauge records</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Emery, K.O.</p> <p>1980-12-01</p> <p>Mean annual <span class="hlt">sea</span> <span class="hlt">levels</span> at 247 tide-gauge stations of the world exhibit a general rise of relative <span class="hlt">sea</span> <span class="hlt">level</span> of about 3 mm/year during the past 40 years. In contrast, general uplift of the land is typical of high northern latitudes, where unloading of the crust by melt of Pleistocene ice sheets is significant. Erratic movements are typical of belts having crustal overthrusting and active volcanism. Short-term (5- and 10-year) records reveal recent changes in rates, but such short time spans may be so influenced by climatic cycles that identification of new trends is difficult, especially with the existing poor distribution and reporting of tide-gauge data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27506974','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27506974"><span id="translatedtitle">Is the detection of accelerated <span class="hlt">sea</span> <span class="hlt">level</span> rise imminent?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fasullo, J T; Nerem, R S; Hamlington, B</p> <p>2016-08-10</p> <p>Global mean <span class="hlt">sea</span> <span class="hlt">level</span> 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 <span class="hlt">sea</span> <span class="hlt">level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011EOSTr..92Q.408S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011EOSTr..92Q.408S"><span id="translatedtitle">Groundwater depletion's contribution to <span class="hlt">sea</span> <span class="hlt">level</span> rise increasing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, Colin</p> <p>2011-11-01</p> <p>Since the turn of the twentieth century, industrial-scale redistribution of water from landlocked aquifers to the ocean has driven up the global average <span class="hlt">sea</span> <span class="hlt">level</span> by more than 12 centimeters. Between 1900 and 2008, roughly 4500 cubic kilometers of water was drawn from the ground, largely to feed an agricultural system increasingly reliant on irrigation. Of that 4500-cubic-kilometer total (nearly the volume of Lake Michigan), 1100 cubic kilometers were pumped out between 2000 and 2008 alone. This early-21st-century groundwater depletion was responsible for raising global <span class="hlt">sea</span> <span class="hlt">level</span> at a rate of 0.4 millimeter per year, an eighth of the observed total. These updated values, falling near the middle of the range of previous estimates, are the product of an investigation by Konikow that drew together a variety of volumetric measurements of groundwater storage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014916','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014916"><span id="translatedtitle">The record of Pliocene <span class="hlt">sea-level</span> change at Enewetak Atoll</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wardlaw, B.R.; Quinn, T.M.</p> <p>1991-01-01</p> <p>Detailed seismic stratigraphy, lithostratigraphy, and chemostratigraphy indicate that atoll-wide subaerial exposure surfaces (major disconformities) developed during major <span class="hlt">sea-level</span> lowstands form prominent seismic reflectors and are coincident with biostratigraphic breaks in the Plio-Pleistocene on Enewetak Atoll. <span class="hlt">Sea-level</span> models based on the stratigraphic position and age of major disconformities suggest a maximum <span class="hlt">sea-level</span> highstand elevation of 36 m above present <span class="hlt">sea</span> <span class="hlt">level</span> and a maximum <span class="hlt">sea-level</span> lowstand elevation of 63 m below present <span class="hlt">sea</span> <span class="hlt">level</span> for the Pliocene. ?? 1991.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991QSRv...10..247W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991QSRv...10..247W"><span id="translatedtitle">The record of Pliocene <span class="hlt">sea-level</span> change at Enewetak Atoll</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wardlaw, Bruce R.; Quinn, Terrence M.</p> <p></p> <p>Detailed seismic stratigraphy, lithostratigraphy, and chemostratigraphy indicate that atoll-wide subaerial exposure surfaces (major disconformities) developed during major <span class="hlt">sea-level</span> lowstands form prominent seismic reflectors and are coincident with biostratigraphic breaks in the Plio-Pleistocene on Enewetak Atoll. <span class="hlt">Sea-level</span> models based on the stratigraphic position and age of major disconformities suggest a maximum <span class="hlt">sea-level</span> highstand elevation of 36 m above present <span class="hlt">sea</span> <span class="hlt">level</span> and a maximum <span class="hlt">sea-level</span> lowstand elevation of 63 m below present <span class="hlt">sea</span> <span class="hlt">level</span> for the Pliocene.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMIN41B3656J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMIN41B3656J"><span id="translatedtitle">The Future of GLOSS <span class="hlt">Sea</span> <span class="hlt">Level</span> Data Archaeology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jevrejeva, S.; Bradshaw, E.; Tamisiea, M. E.; Aarup, T.</p> <p>2014-12-01</p> <p>Long term climate records are rare, consisting of unique and unrepeatable measurements. However, data do exist in analogue form in archives, libraries and other repositories around the world. The Global <span class="hlt">Sea</span> <span class="hlt">Level</span> Observing System (GLOSS) Group of Experts aims to provide advice on locating hidden tide gauge data, scanning and digitising records and quality controlling the resulting data. Long <span class="hlt">sea</span> <span class="hlt">level</span> data time series are used in Intergovernmental Panel on Climate Change (IPCC) assessment reports and climate studies, in oceanography to study changes in ocean currents, tides and storm surges, in geodesy to establish national datum and in geography and geology to monitor coastal land movement. GLOSS has carried out a number of data archaeology activities over the past decade, which have mainly involved sending member organisations questionnaires on their repositories. The Group of Experts is now looking at future developments in <span class="hlt">sea</span> <span class="hlt">level</span> data archaeology and how new technologies coming on line could be used by member organisations to make data digitisation and transcription more efficient. Analogue tide data comes in two forms charts, which record the continuous measurements made by an instrument, usually via a pen trace on paper ledgers containing written values of observations The GLOSS data archaeology web pages will provide a list of software that member organisations have reported to be suitable for the automatic digitisation of tide gauge charts. Transcribing of ledgers has so far proved more labour intensive and is usually conducted by people entering numbers by hand. GLOSS is exploring using Citizen Science techniques, such as those employed by the Old Weather project, to improve the efficiency of transcribing ledgers. The Group of Experts is also looking at recent advances in Handwritten Text Recognition (HTR) technology, which mainly relies on patterns in the written word, but could be adapted to work with the patterns inherent in <span class="hlt">sea</span> <span class="hlt">level</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/0091-97/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/0091-97/report.pdf"><span id="translatedtitle">Global warming, <span class="hlt">sea-level</span> rise, and coastal marsh survival</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cahoon, Donald R.</p> <p>1997-01-01</p> <p>Coastal wetlands are among the most productive ecosystems in the world. These wetlands at the land-ocean margin provide many direct benefits to humans, including habitat for commercially important fisheries and wildlife; storm protection; improved water quality through sediment, nutrient, and pollution removal; recreation; and aesthetic values. These valuable ecosystems will be highly vulnerable to the effects of the rapid rise in <span class="hlt">sea</span> <span class="hlt">level</span> predicted to occur during the next century as a result of global warming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011GeoJI.186.1036T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011GeoJI.186.1036T"><span id="translatedtitle">Ongoing glacial isostatic contributions to observations of <span class="hlt">sea</span> <span class="hlt">level</span> change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tamisiea, Mark E.</p> <p>2011-09-01</p> <p>Studies determining the contribution of water fluxes to <span class="hlt">sea</span> <span class="hlt">level</span> rise typically remove the ongoing effects of glacial isostatic adjustment (GIA). Unfortunately, use of inconsistent terminology between various disciplines has caused confusion as to how contributions from GIA should be removed from altimetry and GRACE measurements. In this paper, we review the physics of the GIA corrections applicable to these measurements and discuss the differing nomenclature between the GIA literature and other studies of <span class="hlt">sea</span> <span class="hlt">level</span> change. We then examine a range of estimates for the GIA contribution derived by varying the Earth and ice models employed in the prediction. We find, similar to early studies, that GIA produces a small (compared to the observed value) but systematic contribution to the altimetry estimates, with a maximum range of -0.15 to -0.5 mm yr-1. Moreover, we also find that the GIA contribution to the mass change measured by GRACE over the ocean is significant. In this regard, we demonstrate that confusion in nomenclature between the terms 'absolute <span class="hlt">sea</span> <span class="hlt">level</span>' and 'geoid' has led to an overestimation of this contribution in some previous studies. A component of this overestimation is the incorrect inclusion of the direct effect of the contemporaneous perturbations of the rotation vector, which leads to a factor of ˜two larger value of the degree two, order one spherical harmonic component of the model results. Aside from this confusion, uncertainties in Earth model structure and ice sheet history yield a spread of up to 1.4 mm yr-1 in the estimates of this contribution. However, even if the ice and Earth models were perfectly known, the processing techniques used in GRACE data analysis can introduce variations of up to 0.4 mm yr-1. Thus, we conclude that a single-valued 'GIA correction' is not appropriate for <span class="hlt">sea</span> <span class="hlt">level</span> studies based on gravity data; each study must estimate a bound on the GIA correction consistent with the adopted data-analysis scheme.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.8447M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.8447M"><span id="translatedtitle">Mean Tide <span class="hlt">Level</span> Data in the PSMSL Mean <span class="hlt">Sea</span> <span class="hlt">Level</span> Dataset</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matthews, Andrew; Bradshaw, Elizabeth; Gordon, Kathy; Jevrejeva, Svetlana; Rickards, Lesley; Tamisiea, Mark; Williams, Simon; Woodworth, Philip</p> <p>2016-04-01</p> <p>The Permanent Service for Mean <span class="hlt">Sea</span> <span class="hlt">Level</span> (PSMSL) is the internationally recognised global <span class="hlt">sea</span> <span class="hlt">level</span> data bank for long term <span class="hlt">sea</span> <span class="hlt">level</span> change information from tide gauges. Established in 1933, the PSMSL continues to be responsible for the collection, publication, analysis and interpretation of <span class="hlt">sea</span> <span class="hlt">level</span> data. The PSMSL operates under the auspices of the International Council for Science (ICSU), is a regular member of the ICSU World Data System and is associated with the International Association for the Physical Sciences of the Oceans (IAPSO) and the International Association of Geodesy (IAG). The PSMSL continues to work closely with other members of the <span class="hlt">sea</span> <span class="hlt">level</span> community through the Intergovernmental Oceanographic Commission's Global <span class="hlt">Sea</span> <span class="hlt">Level</span> Observing System (GLOSS). Currently, the PSMSL data bank holds over 67,000 station-years of monthly and annual mean <span class="hlt">sea</span> <span class="hlt">level</span> data from over 2250 tide gauge stations. Data from each site are quality controlled and, wherever possible, reduced to a common datum, whose stability is monitored through a network of geodetic benchmarks. PSMSL also distributes a data bank of measurements taken from in-situ ocean bottom pressure recorders. Most of the records in the main PSMSL dataset indicate mean <span class="hlt">sea</span> <span class="hlt">level</span> (MSL), derived from high-frequency tide gauge data, with sampling typically once per hour or higher. However, some of the older data is based on mean tide <span class="hlt">level</span> (MTL), which is obtained from measurements taken at high and low tide only. While usually very close, MSL and MTL can occasionally differ by many centimetres, particularly in shallow water locations. As a result, care must be taken when using long <span class="hlt">sea</span> <span class="hlt">level</span> records that contain periods of MTL data. Previously, periods during which the values indicated MTL rather than MSL were noted in the documentation, and sometimes suggested corrections were supplied. However, these comments were easy to miss, particularly in large scale studies that used multiple stations from across</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/638181','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/638181"><span id="translatedtitle">Glacier calving, dynamics, and <span class="hlt">sea-level</span> rise. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Meier, M.F.; Pfeffer, W.T.; Amadei, B.</p> <p>1998-08-01</p> <p>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 <span class="hlt">sea</span> <span class="hlt">level</span>. Another fundamental problem has to do with incomplete knowledge of glacier areas and volumes, needed for analyses of <span class="hlt">sea-level</span> change due to changing climate. The authors proposed to develop an improved ability to predict the future contributions of glaciers to <span class="hlt">sea</span> <span class="hlt">level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6119945','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6119945"><span id="translatedtitle">A Mid-Holocene <span class="hlt">sea</span> <span class="hlt">level</span> fluctuation in South Carolina</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gayes, P.T.; Nelson, D.D. . Marine and Wetland Studies); Scott, D.B.; Collins, E. . Centre for Marine Geology)</p> <p>1993-03-01</p> <p>A high stand of relative <span class="hlt">sea</span> <span class="hlt">level</span> occurred at 4.2 ka in Murrells Inlet on the northern coast of South Carolina. The event was identified using benthic foraminiferal zonations, marsh stratigraphic relations and radiocarbon data. This highstand reached a maximum of approximately [minus]1 meter MSD and was followed by a fall of 2 meters until 3.6 ka. Subsequent to 3.6 ka submergence was slow averaging 10 cm/century to the present. A second smaller fluctuation may have occurred around 2.5 ka but remains poorly constrained. Although a Mid-Holocene highstand had been suggested by others, it has not been well constrained. New data from North Inlet, South Carolina also record a baselevel change in the Mid-Holocene. Strong differential submergence between Murrells Inlet and Santee Delta, South Carolina, has occurred over the last 4 ka, probably as a result of sediment loading by and subsidence of, the Santee Delta. The occurrence of the 4.2 ka highstand corresponds in the range (7 [minus] 4 ka) to that of the Holocene Hypsithermal. The rate and magnitude of the relative <span class="hlt">sea</span> <span class="hlt">level</span> fluctuation are similar to those projected for future flooding and suggest that the evaluation of the Hypsithermal highstand may provide an insight to continued <span class="hlt">sea-level</span> rise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730009903','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730009903"><span id="translatedtitle">Objective <span class="hlt">sea</span> <span class="hlt">level</span> pressure analysis for sparse data areas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Druyan, L. M.</p> <p>1972-01-01</p> <p>A computer procedure was used to analyze the pressure distribution over the North Pacific Ocean for eleven synoptic times in February, 1967. Independent knowledge of the central pressures of lows is shown to reduce the analysis errors for very sparse data coverage. The application of planned remote sensing of <span class="hlt">sea-level</span> wind speeds is shown to make a significant contribution to the quality of the analysis especially in the high gradient mid-latitudes and for sparse coverage of conventional observations (such as over Southern Hemisphere oceans). Uniform distribution of the available observations of <span class="hlt">sea-level</span> pressure and wind velocity yields results far superior to those derived from a random distribution. A generalization of the results indicates that the average lower limit for analysis errors is between 2 and 2.5 mb based on the perfect specification of the magnitude of the <span class="hlt">sea-level</span> pressure gradient from a known verification analysis. A less than perfect specification will derive from wind-pressure relationships applied to satellite observed wind speeds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70098419','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70098419"><span id="translatedtitle">How mangrove forests adjust to rising <span class="hlt">sea</span> <span class="hlt">level</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Krauss, Ken W.; McKee, Karen L.; Lovelock, Catherine E.; Cahoon, Donald R.; Saintilan, Neil; Reef, Ruth; Chen, Luzhen</p> <p>2014-01-01</p> <p>Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to <span class="hlt">sea-level</span> rise. To persist, mangrove ecosystems must adjust to rising <span class="hlt">sea</span> <span class="hlt">level</span> by building vertically or become submerged. Mangroves may directly or indirectly influence soil accretion processes through the production and accumulation of organic matter, as well as the trapping and retention of mineral sediment. In this review, we provide a general overview of research on mangrove elevation dynamics, emphasizing the role of the vegetation in maintaining soil surface elevations (i.e. position of the soil surface in the vertical plane). We summarize the primary ways in which mangroves may influence sediment accretion and vertical land development, for example, through root contributions to soil volume and upward expansion of the soil surface. We also examine how hydrological, geomorphological and climatic processes may interact with plant processes to influence mangrove capacity to keep pace with rising <span class="hlt">sea</span> <span class="hlt">level</span>. We draw on a variety of studies to describe the important, and often under-appreciated, role that plants play in shaping the trajectory of an ecosystem undergoing change.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70148342','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70148342"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span>, paleogeography, and archeology on California's Northern Channel Islands</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reeder-Myers, Leslie; Erlandson, Jon M.; Muhs, Daniel R.; Rick, Torben C.</p> <p>2015-01-01</p> <p><span class="hlt">Sea-level</span> 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 <span class="hlt">sea-level</span> 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. <span class="hlt">Sea</span> <span class="hlt">level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70156427','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70156427"><span id="translatedtitle">Mangrove sedimentation and response to relative <span class="hlt">sea-level</span> rise</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Woodroffe, CD; Rogers, K.; Mckee, Karen L.; Lovelock, CE; Mendelssohn, IA; Saintilan, N.</p> <p>2016-01-01</p> <p>Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions influence mangrove distributions, primarily related to elevation and hydroperiod; this review considers how these adjust through time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks; tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon, but also contain paleoenvironmental records of adjustments to past <span class="hlt">sea-level</span> changes. Radiometric dating indicates long-term sedimentation, whereas Surface Elevation Table-Marker Horizon measurements (SET-MH) provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative <span class="hlt">sea-level</span> rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative <span class="hlt">sea-level</span> rise. However, many human pressures threaten mangroves, resulting in continuing decline in their extent throughout the tropics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5028851','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5028851"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> rise in Louisiana and Gulf of Mexico</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ramsey, K.; Penland, S. )</p> <p>1989-09-01</p> <p>Data from two tide-gage networks in Louisiana and the northern Gulf of Mexico were analyzed to determine local and regional trends in relative <span class="hlt">sea</span> <span class="hlt">level</span> rise. The US Army Corps of Engineers (USACE) maintains a network of 83 tide-gage stations throughout coastal Louisiana. Of these, 20 have records for two lunar nodal cycles or more, and some date back to 1933. The authors used the USACE data set to determine the local and regional character of relative <span class="hlt">sea</span> <span class="hlt">level</span> rise in Louisiana. The National ocean Survey (NOS) maintains nine tide gage stations throughout the northern Gulf of Mexico in Texas, Louisiana, Mississippi, Alabama, and Florida. All of the records of these stations exceed two lunar nodal cycles, and some date back to 1908. The authors used the NOS data set to determine the character of relative <span class="hlt">sea</span> <span class="hlt">level</span> rise throughout the northern Gulf of Mexico. This investigation updates and extends the previous systematic regional tide gage analysis (which covered 1908-1983) to 1988.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26407146','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26407146"><span id="translatedtitle">Mangrove Sedimentation and Response to Relative <span class="hlt">Sea-Level</span> Rise.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Woodroffe, C D; Rogers, K; McKee, K L; Lovelock, C E; Mendelssohn, I A; Saintilan, N</p> <p>2016-01-01</p> <p>Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions, related primarily to elevation and hydroperiod, influence mangrove distributions; this review considers how these distributions change over time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks, and tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon but also contain paleoenvironmental records of adjustments to past <span class="hlt">sea-level</span> changes. Radiometric dating indicates long-term sedimentation, whereas measurements made using surface elevation tables and marker horizons provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative <span class="hlt">sea-level</span> rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative <span class="hlt">sea-level</span> rise. However, many human pressures threaten mangroves, resulting in a continuing decline in their extent throughout the tropics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24251960','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24251960"><span id="translatedtitle">How mangrove forests adjust to rising <span class="hlt">sea</span> <span class="hlt">level</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Krauss, Ken W; McKee, Karen L; Lovelock, Catherine E; Cahoon, Donald R; Saintilan, Neil; Reef, Ruth; Chen, Luzhen</p> <p>2014-04-01</p> <p>Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to <span class="hlt">sea-level</span> rise. To persist, mangrove ecosystems must adjust to rising <span class="hlt">sea</span> <span class="hlt">level</span> by building vertically or become submerged. Mangroves may directly or indirectly influence soil accretion processes through the production and accumulation of organic matter, as well as the trapping and retention of mineral sediment. In this review, we provide a general overview of research on mangrove elevation dynamics, emphasizing the role of the vegetation in maintaining soil surface elevations (i.e. position of the soil surface in the vertical plane). We summarize the primary ways in which mangroves may influence sediment accretion and vertical land development, for example, through root contributions to soil volume and upward expansion of the soil surface. We also examine how hydrological, geomorphological and climatic processes may interact with plant processes to influence mangrove capacity to keep pace with rising <span class="hlt">sea</span> <span class="hlt">level</span>. We draw on a variety of studies to describe the important, and often under-appreciated, role that plants play in shaping the trajectory of an ecosystem undergoing change.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ARMS....8..243W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ARMS....8..243W"><span id="translatedtitle">Mangrove Sedimentation and Response to Relative <span class="hlt">Sea-Level</span> Rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woodroffe, C. D.; Rogers, K.; McKee, K. L.; Lovelock, C. E.; Mendelssohn, I. A.; Saintilan, N.</p> <p>2016-01-01</p> <p>Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions, related primarily to elevation and hydroperiod, influence mangrove distributions; this review considers how these distributions change over time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic, vary between and within different settings. Abundant terrigenous sediment can form dynamic mudbanks, and tides redistribute sediment, contrasting with mangrove peat in sediment-starved carbonate settings. Sediments underlying mangroves sequester carbon but also contain paleoenvironmental records of adjustments to past <span class="hlt">sea-level</span> changes. Radiometric dating indicates long-term sedimentation, whereas measurements made using surface elevation tables and marker horizons provide shorter perspectives, indicating shallow subsurface processes of root growth and substrate autocompaction. Many tropical deltas also experience deep subsidence, which augments relative <span class="hlt">sea-level</span> rise. The persistence of mangroves implies an ability to cope with moderately high rates of relative <span class="hlt">sea-level</span> rise. However, many human pressures threaten mangroves, resulting in a continuing decline in their extent throughout the tropics. *</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015QuRes..83..263R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015QuRes..83..263R"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span>, paleogeography, and archeology on California's Northern Channel Islands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reeder-Myers, Leslie; Erlandson, Jon M.; Muhs, Daniel R.; Rick, Torben C.</p> <p>2015-03-01</p> <p><span class="hlt">Sea-level</span> 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 <span class="hlt">sea-level</span> 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. <span class="hlt">Sea</span> <span class="hlt">level</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B31I..06W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B31I..06W"><span id="translatedtitle">Uncertainty In Greenhouse Gas Emissions On Carbon Sequestration In Coastal and Freshwater Wetlands of the Mississippi River Delta: A Subsiding Coastline as a Proxy for Future Global <span class="hlt">Sea</span> <span class="hlt">Level</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>White, J. R.; DeLaune, R. D.; Roy, E. D.; Corstanje, R.</p> <p>2014-12-01</p> <p>The highly visible phenomenon of wetland loss in coastal Louisiana (LA) is examined through the prism of carbon accumulation, wetland loss and greenhouse gas (GHG) emissions. The Mississippi River Deltaic region experiences higher relative <span class="hlt">sea</span> <span class="hlt">level</span> rise due to coupled subsidence and <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> rise allowing this region to serve as a proxy for future projected golbal <span class="hlt">sea</span> <span class="hlt">level</span> rise. Carbon storage or sequestration in rapidly subsiding LA coastal marsh soils is based on vertical marsh accretion and areal change data. While coastal marshes sequester significant amount of carbon through vertical accretion, large amounts of carbon, previously sequested in the soil profile is lost through annual deterioration of these coastal marshes as well as through GHG emissions. Efforts are underway in Louisiana to access the carbon credit market in order to provide significant funding for coastal restoration projects. However, there is very large uncertainty on GHG emission rates related to both marsh type and temporal (daily and seasonal) effects. Very little data currently exists which addresses this uncertainty which can significantly affect the carbon credit value of a particular wetland system. We provide an analysis of GHG emission rates for coastal freshwater, brackish and and salt marshes compared to the net soil carbon sequestration rate. Results demonstrate that there is very high uncertainty on GHG emissions which can substantially alter the carbon credit value of a particular wetland system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26587269','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26587269"><span id="translatedtitle">Nest inundation from <span class="hlt">sea-level</span> rise threatens <span class="hlt">sea</span> turtle population viability.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pike, David A; Roznik, Elizabeth A; Bell, Ian</p> <p>2015-07-01</p> <p>Contemporary <span class="hlt">sea-level</span> rise will inundate coastal habitats with seawater more frequently, disrupting the life cycles of terrestrial fauna well before permanent habitat loss occurs. <span class="hlt">Sea</span> turtles are reliant on low-lying coastal habitats worldwide for nesting, where eggs buried in the sand remain vulnerable to inundation until hatching. We show that saltwater inundation directly lowers the viability of green turtle eggs (Chelonia mydas) collected from the world's largest green turtle nesting rookery at Raine Island, Australia, which is undergoing enigmatic decline. Inundation for 1 or 3 h reduced egg viability by less than 10%, whereas inundation for 6 h reduced viability by approximately 30%. All embryonic developmental stages were vulnerable to mortality from saltwater inundation. Although the hatchlings that emerged from inundated eggs displayed normal physical and behavioural traits, hypoxia during incubation could influence other aspects of the physiology or behaviour of developing embryos, such as learning or spatial orientation. Saltwater inundation can directly lower hatching success, but it does not completely explain the consistently low rates of hatchling production observed on Raine Island. More frequent nest inundation associated with <span class="hlt">sea-level</span> rise will increase variability in <span class="hlt">sea</span> turtle hatching success spatially and temporally, due to direct and indirect impacts of saltwater inundation on developing embryos.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA11002&hterms=Rising+sea+levels&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DRising%2Bsea%2Blevels','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA11002&hterms=Rising+sea+levels&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DRising%2Bsea%2Blevels"><span id="translatedtitle">Portrait of a Warming Ocean and Rising <span class="hlt">Sea</span> <span class="hlt">Levels</span>: Trend of <span class="hlt">Sea</span> <span class="hlt">Level</span> Change 1993-2008</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2008-01-01</p> <p><p/> Warming water and melting land ice have raised global mean <span class="hlt">sea</span> <span class="hlt">level</span> 4.5 centimeters (1.7 inches) from 1993 to 2008. But the rise is by no means uniform. This image, created with <span class="hlt">sea</span> surface height data from the Topex/Poseidon and Jason-1 satellites, shows exactly where <span class="hlt">sea</span> <span class="hlt">level</span> has changed during this time and how quickly these changes have occurred. <p/> It's also a road map showing where the ocean currently stores the growing amount of heat it is absorbing from Earth's atmosphere and the heat it receives directly from the Sun. The warmer the water, the higher the <span class="hlt">sea</span> surface rises. The location of heat in the ocean and its movement around the globe play a pivotal role in Earth's climate. <p/> Light blue indicates areas in which <span class="hlt">sea</span> <span class="hlt">level</span> has remained relatively constant since 1993. White, red, and yellow are regions where <span class="hlt">sea</span> <span class="hlt">levels</span> have risen the most rapidly up to 10 millimeters per year and which contain the most heat. Green areas have also risen, but more moderately. Purple and dark blue show where <span class="hlt">sea</span> <span class="hlt">levels</span> have dropped, due to cooler water. <p/> The dramatic variation in <span class="hlt">sea</span> surface heights and heat content across the ocean are due to winds, currents and long-term changes in patterns of circulation. From 1993 to 2008, the largest area of rapidly rising <span class="hlt">sea</span> <span class="hlt">levels</span> and the greatest concentration of heat has been in the Pacific, which now shows the characteristics of the Pacific Decadal Oscillation (PDO), a feature that can last 10 to 20 years or even longer. <p/> In this 'cool' phase, the PDO appears as a horseshoe-shaped pattern of warm water in the Western Pacific reaching from the far north to the Southern Ocean enclosing a large wedge of cool water with low <span class="hlt">sea</span> surface heights in the eastern Pacific. This ocean/climate phenomenon may be caused by wind-driven Rossby waves. Thousands of kilometers long, these waves move from east to west on either side of the equator changing the distribution of water mass and heat. <p/> This image of <span class="hlt">sea</span> <span class="hlt">level</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70031023','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70031023"><span id="translatedtitle">Holocene <span class="hlt">sea</span> <span class="hlt">level</span> and climate change in the Black <span class="hlt">Sea</span>: Multiple marine incursions related to freshwater discharge events</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Martin, R.E.; Leorri, E.; McLaughlin, P.P.</p> <p>2007-01-01</p> <p>Repeated marine invasions of the Black <span class="hlt">Sea</span> during the Holocene have been inferred by many eastern scientists as resulting from episodes of marine inflow from the Mediterranean beneath a brackish outflow from the Black <span class="hlt">Sea</span>. We support this scenario but a fundamental question remains: What caused the repeated marine invasions? We offer an hypothesis for the repeated marine invasions of the Black <span class="hlt">Sea</span> based on: (1) the overall similarity of <span class="hlt">sea-level</span> curves from both tectonically quiescent and active margins of the Black <span class="hlt">Sea</span> and their similarity to a sequence stratigraphic record from the US mid-Atlantic coast. The similarity of the records from two widely-separated regions suggests their common response to documented Holocene climate ocean-atmosphere reorganizations (coolings); (2) the fact that in the modern Black <span class="hlt">Sea</span>, freshwater runoff from surrounding rivers dominates over evaporation, so that excess runoff might have temporarily raised Black <span class="hlt">Sea</span> <span class="hlt">level</span> (although the Black <span class="hlt">Sea</span> would have remained brackish). Following the initial invasion of the Black <span class="hlt">Sea</span> by marine Mediterranean waters (through the Marmara <span class="hlt">Sea</span>) in the early Holocene, repeated marine incursions were modulated, or perhaps even caused, by freshwater discharge to the Black <span class="hlt">Sea</span>. Climatic amelioration (warming) following each documented ocean-atmosphere reorganization during the Holocene likely shifted precipitation patterns in the surrounding region and caused mountain glaciers to retreat, increasing freshwater runoff above modern values and temporarily contributing to an increase of Black <span class="hlt">Sea</span> <span class="hlt">level</span>. Freshwater-to-brackish water discharges into the Black <span class="hlt">Sea</span> initially slowed marine inflow but upon mixing of runoff with more marine waters beneath them and their eventual exit through the Bosphorus, marine inflow increased again, accounting for the repeated marine invasions. The magnitude of the hydrologic and <span class="hlt">sea-level</span> fluctuations became increasingly attenuated through the Holocene, as reflected by Black</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005SedG..176...43E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005SedG..176...43E"><span id="translatedtitle">Controls on Precambrian <span class="hlt">sea</span> <span class="hlt">level</span> change and sedimentary cyclicity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eriksson, P. G.; Catuneanu, O.; Nelson, D. R.; Popa, M.</p> <p>2005-04-01</p> <p>Although uniformitarianism applies in a general sense to the controls on relative and global <span class="hlt">sea</span> <span class="hlt">level</span> change, some influences thereon were more prominent in the Precambrian. Short-term base <span class="hlt">level</span> change due to waves and tides may have been enhanced due to possibly more uniform circulation systems on wide, low gradient Precambrian shelves. The lack of evidence for global glacial events in the Precambrian record implies that intraplate stresses and cyclic changes to Earth's geoid were more likely explanations for third-order <span class="hlt">sea</span> <span class="hlt">level</span> change than glacio-eustasy. Higher heat flow in the earlier Precambrian may have led to more rapid tectonic plate formation, transport and destruction, along with an increased role for hot spots, aseismic ridges and mantle plumes (superplumes), all of which may have influenced cyclic sedimentation within the ocean basins. A weak cyclicity in the occurrence of plume events has an approximate duration comparable to that of first-order (supercontinental cycle) <span class="hlt">sea</span> <span class="hlt">level</span> change. Second-order cyclicity in the Precambrian largely reflects the influences of thermal epeirogeny, changes to mid-ocean ridge volume as well as to ridge growth and decay rates, and cratonic marginal downwarping concomitant with either sediment loading or extensional tectonism. Third-order cycles of <span class="hlt">sea</span> <span class="hlt">level</span> change in the Precambrian also reflected cyclic loading/unloading within flexural foreland basin settings, and filling/deflation of magma chambers associated with island arc evolution. The relatively limited number of studies of Precambrian sequence stratigraphy allows some preliminary conclusions to be drawn on duration of the first three orders of cyclicity. Archaean greenstone basins appear to have had first- and second-order cycle durations analogous to Phanerozoic equivalents, supporting steady state tectonics throughout Earth history. In direct contrast, however, preserved basin-fills from Neoarchaean-Palaeoproterozoic cratonic terranes have first- and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.1898S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.1898S"><span id="translatedtitle">Causes and consequences of short-term <span class="hlt">sea-level</span> changes in the Cretaceous green- and "hothouse": Topics and context of IGCP Project 609</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sames, Benjamin; Wagreich, Michael</p> <p>2015-04-01</p> <p> Cretaceous <span class="hlt">sea-level</span> changes will be tied to the new, high-resolution time scales, using <span class="hlt">sea</span>-water isotope curves and cyclostratigraphic records reflecting the major astronomical (405, 100 kyr eccentricity) cycles. This will determine whether the recognized <span class="hlt">sea-level</span> changes are of regional or global significance and will also indicate their possible relation to climate and/or tectonic events. Within the scope of the project, a wide range of research questions is addressed, such as: 1) Are <span class="hlt">sea-level</span> changes regional (tectonically induced) or global (<span class="hlt">eustatic</span>)?; 2) How fast are rates of (short-term) <span class="hlt">sea-level</span> changes during the Cretaceous super-greenhouse period?; 3) Are specific <span class="hlt">sea-level</span> peaks associated with glacial episodes - or other climate and environmental events such as ocean anoxia and oxidation events? Geophysicists, structural geologists, stratigraphers, geochemists and sedimentologists from all over the world are working together towards advances in the understanding of the processes behind Cretaceous short-term <span class="hlt">sea-level</span> changes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.......110R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.......110R"><span id="translatedtitle">Modeling future <span class="hlt">sea</span> <span class="hlt">level</span> rise from melting glaciers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Radic, Valentina</p> <p></p> <p>Melting mountain glaciers and ice caps (MG&IC) are the second largest contributor to rising <span class="hlt">sea</span> <span class="hlt">level</span> after thermal expansion of the oceans and are likely to remain the dominant glaciological contributor to rising <span class="hlt">sea</span> <span class="hlt">level</span> in the 21st century. The aim of this work is to project 21st century volume changes of all MG&IC and to provide systematic analysis of uncertainties originating from different sources in the calculation. I provide an ensemble of 21st century volume projections for all MG&IC from the World Glacier Inventory by modeling the surface mass balance coupled with volume-area-length scaling and forced with temperature and precipitation scenarios from four Global Climate Models (GCMs). By upscaling the volume projections through a regionally differentiated approach to all MG&IC outside Greenland and Antarctica (514,380 km 2) I estimated total volume loss for the time period 2001-2100 to range from 0.039 to 0.150 m <span class="hlt">sea</span> <span class="hlt">level</span> equivalent. While three GCMs agree that Alaskan glaciers are the main contributors to the projected <span class="hlt">sea</span> <span class="hlt">level</span> rise, one GCM projected the largest total volume loss mainly due to Arctic MG&IC. The uncertainties in the projections are addressed by a series of sensitivity tests applied in the methodology for assessment of global volume changes and on individual case studies for particular glaciers. Special emphasis is put on the uncertainties in volume-area scaling. For both, individual and global assessments of volume changes, the choice of GCM forcing glacier models is shown to be the largest source of quantified uncertainties in the projections. Another major source of uncertainty is the temperature forcing in the mass balance model depending on the quality of climate reanalysis products (ERA-40) in order to simulate the local temperatures on a mountain glacier or ice cap. Other uncertainties in the methods are associated with volume-area-length scaling as a tool for deriving glacier initial volumes and glacier geometry changes in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23092012','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23092012"><span id="translatedtitle">Predicted eelgrass response to <span class="hlt">sea</span> <span class="hlt">level</span> rise and its availability to foraging Black Brant in Pacific coast estuaries.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shaughnessy, Frank J; Gilkerson, Whelan; Black, Jeffrey M; Ward, David H; Petrie, Mark</p> <p>2012-09-01</p> <p>Managers need to predict how animals will respond to habitat redistributions caused by climate change. Our objective was to model the effects of <span class="hlt">sea</span> <span class="hlt">level</span> rise on total eelgrass (Zostera marina) habitat area and on the amount of that area that is accessible to Brant geese (Branta bernicla), specialist grazers of eelgrass. Digital elevation models were developed for seven estuaries from Alaska, Washington, California (USA), and Mexico. Scenarios of future total eelgrass area were derived from combinations of estuarine specific sediment and tectonic rates (i.e., bottom change rate) with three rates of <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> rise (ESLR). Percentages of total eelgrass areas that were accessible to foraging Brant were determined for December when the birds overwinter at more southerly sites and in April as they move north to sites where they build body stores on their way to nesting areas in Alaska. The modeling showed that accessible eelgrass area could be lower than total area due to how daytime low-tide height, eelgrass shoot length, and the upper elevation of eelgrass determined Brant-reaching depth. Projections of future eelgrass area indicated that present-day ESLR (2.8 mm/yr) and bottom change rates should sustain the current pattern of estuarine use by Brant except in Morro Bay, where use should decrease because eelgrass is being ejected from this estuary by a positive bottom change rate. Higher ESLR rates (6.3 and 12.7 mm/yr) should result in less Brant use of estuaries at the northern and southern ends of the flyway, particularly during the winter, but more use of mid-latitude estuaries. The capacity of mid-latitude estuaries to function as Brant feeding refugia, or for these estuaries and Izembek Lagoon to provide drift rather than attached leaves, is eventually limited by the decrease in total eelgrass area, which is a result of a light extinction affect on the eelgrass, or the habitat being pushed out of the estuary by positive tectonic rates. Management</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70041035','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70041035"><span id="translatedtitle">Predicted eelgrass response to <span class="hlt">sea</span> <span class="hlt">level</span> rise and its availability to foraging Black Brant in Pacific coast estuaries</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shaughnessy, Frank J.; Gilkerson, Whelan; Black, Jeffrey M.; Ward, David H.; Petrie, Mark</p> <p>2012-01-01</p> <p>Managers need to predict how animals will respond to habitat redistributions caused by climate change. Our objective was to model the effects of <span class="hlt">sea</span> <span class="hlt">level</span> rise on total eelgrass (Zostera marina) habitat area and on the amount of that area that is accessible to Brant geese (Branta bernicla), specialist grazers of eelgrass. Digital elevation models were developed for seven estuaries from Alaska, Washington, California (USA), and Mexico. Scenarios of future total eelgrass area were derived from combinations of estuarine specific sediment and tectonic rates (i.e., bottom change rate) with three rates of <span class="hlt">eustatic</span> <span class="hlt">sea</span> <span class="hlt">level</span> rise (ESLR). Percentages of total eelgrass areas that were accessible to foraging Brant were determined for December when the birds overwinter at more southerly sites and in April as they move north to sites where they build body stores on their way to nesting areas in Alaska. The modeling showed that accessible eelgrass area could be lower than total area due to how daytime low-tide height, eelgrass shoot length, and the upper elevation of eelgrass determined Brant-reaching depth. Projections of future eelgrass area indicated that present-day ESLR (2.8 mm/yr) and bottom change rates should sustain the current pattern of estuarine use by Brant except in Morro Bay, where use should decrease because eelgrass is being ejected from this estuary by a positive bottom change rate. Higher ESLR rates (6.3 and 12.7 mm/yr) should result in less Brant use of estuaries at the northern and southern ends of the flyway, particularly during the winter, but more use of mid-latitude estuaries. The capacity of mid-latitude estuaries to function as Brant feeding refugia, or for these estuaries and Izembek Lagoon to provide drift rather than attached leaves, is eventually limited by the decrease in total eelgrass area, which is a result of a light extinction affect on the eelgrass, or the habitat being pushed out of the estuary by positive tectonic rates. Management</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNH23C..03D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNH23C..03D"><span id="translatedtitle"><span class="hlt">Sea-Level</span> Rise for California, Oregon, and Washington: Present and Future</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dalrymple, R. A.</p> <p>2012-12-01</p> <p>This talk discusses the results of a NRC study on U.S. west coast <span class="hlt">sea-level</span> rise, completed in June. The first part of the study deals with global <span class="hlt">sea</span> <span class="hlt">level</span> rise, utilizing data generated since the IPCC (2007) report and examining each of the major contributors to <span class="hlt">sea-level</span> risel: thermal expansion of <span class="hlt">sea</span> water in response to a warming atmosphere and ice melt from glaciers, ice caps, and ice sheets. Results show that land ice melt is currently the largest contributor to <span class="hlt">sea</span> <span class="hlt">level</span> rise. Predictions of global <span class="hlt">sea</span> <span class="hlt">level</span> are developed for 2030, 2050, and 2100. Next, regional <span class="hlt">sea</span> <span class="hlt">level</span> is determined by including the effects of local vertical land motions, from tectonics, subsidence, and the spatial distribution of ice melt <span class="hlt">sea</span> <span class="hlt">level</span> contributions (<span class="hlt">sea</span> <span class="hlt">level</span> fingerprinting). Of particular interest is the potential of a Cascadia subduction zone earthquake that could add more than a meter of <span class="hlt">sea-level</span> rise in minutes in addition to the expected <span class="hlt">sea</span> <span class="hlt">level</span> rise. Again, predictions of <span class="hlt">sea-level</span> rise for the shoreline of the west coast for 2030, 2050, and 2100 are determined. Implications of <span class="hlt">sea</span> <span class="hlt">level</span> rise on storminess, and the erosion of beaches, coastal cliffs, and wetlands are discussed as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.1599Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.1599Y"><span id="translatedtitle">Grain-size based <span class="hlt">sea-level</span> reconstruction in the south Bohai <span class="hlt">Sea</span> during the past 135 kyr</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yi, Liang; Chen, Yanping</p> <p>2013-04-01</p> <p>Future anthropogenic <span class="hlt">sea-level</span> rise and its impact on coastal regions is an important issue facing human civilizations. Due to the short nature of the instrumental record of <span class="hlt">sea-level</span> change, development of proxies for <span class="hlt">sea-level</span> change prior to the advent of instrumental records is essential to reconstruct long-term background <span class="hlt">sea-level</span> changes on local, regional and global scales. Two of the most widely used approaches for past <span class="hlt">sea-level</span> changes are: (1) exploitation of dated geomorphologic features such as coastal sands (e.g. Mauz and Hassler, 2000), salt marsh (e.g. Madsen et al., 2007), terraces (e.g. Chappell et al., 1996), and other coastal sediments (e.g. Zong et al., 2003); and (2) <span class="hlt">sea-level</span> transfer functions based on faunal assemblages such as testate amoebae (e.g. Charman et al., 2002), foraminifera (e.g. Chappell and Shackleton, 1986; Horton, 1997), and diatoms (e.g. Horton et al., 2006). While a variety of methods has been developed to reconstruct palaeo-changes in <span class="hlt">sea</span> <span class="hlt">level</span>, many regions, including the Bohai <span class="hlt">Sea</span>, China, still lack detailed relative <span class="hlt">sea-level</span> curves extending back to the Pleistocene (Yi et al., 2012). For example, coral terraces are absent in the Bohai <span class="hlt">Sea</span>, and the poor preservation of faunal assemblages makes development of a transfer function for a relative <span class="hlt">sea-level</span> reconstruction unfeasible. In contrast, frequent alternations between transgression and regression has presumably imprinted <span class="hlt">sea-level</span> change on the grain size distribution of Bohai <span class="hlt">Sea</span> sediments, which varies from medium silt to coarse sand during the late Quaternary (IOCAS, 1985). Advantages of grainsize-based relative <span class="hlt">sea-level</span> transfer function approaches are that they require smaller sample sizes, allowing for replication, faster measurement and higher spatial or temporal resolution at a fraction of the cost of detail micro-palaeontological analysis (Yi et al., 2012). Here, we employ numerical methods to partition sediment grain size using a combined database of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70029895','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70029895"><span id="translatedtitle">Holocene <span class="hlt">sea-level</span> oscillations and environmental changes on the Eastern Black <span class="hlt">Sea</span> shelf</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ivanova, E.V.; Murdmaa, I.O.; Chepalyga, A.L.; Cronin, T. M.; Pasechnik, I.V.; Levchenko, O.V.; Howe, S.S.; Manushkina, A.V.; Platonova, E.A.</p> <p>2007-01-01</p> <p>A multi-proxy study of four sediment cores from the Eastern (Caucasian) Black <span class="hlt">Sea</span> shelf revealed five transgressive-regressive cycles overprinted on the general trend of glacioeustatic <span class="hlt">sea-level</span> rise during the last 11,000??14C yr. These cycles are well represented in micro-and macrofossil assemblages, sedimentation rates, and grain size variations. The oldest recovered sediments were deposited in the Neoeuxinian semi-freshwater basin (??? 10,500-9000??14C yr BP) and contain a Caspian-type mollusk fauna dominated by Dreissena rostriformis. Low ??18O and ??13C values are measured on this species. The first appearance of marine mollusks and ostracodes from the Mediterranean is established in this part of the Black <span class="hlt">Sea</span> at ??? 8200??14C yr BP, i.e., about 1000-2000??yr later than the appearance of marine microfossils in the deeper part of the <span class="hlt">sea</span>. The Early Holocene (Bugazian to Vityazevian) condensed section of shell and shelly mud sediments with at least two hiatuses represent a high-energy shelf-edge facies. It contains a transitional assemblage representing a mixture of Caspian and Mediterranean fauna. This pattern suggests a dual-flow regime via the Bosphorus after 8200??14C yr BP. Caspian species disappear and oligohaline species decrease in abundance during the Vityazevian-Prekalamitian cycle. Later, during the Middle to Late Holocene, low <span class="hlt">sea-level</span> stands are characterized by shell layers, whereas silty mud with various mollusk and ostracode assemblages rapidly accumulated during transgressions. Restricted mud accumulation, as well as benthic faunal composition and abundance, suggest high-energy and well-ventilated bottom water during low <span class="hlt">sea-level</span> stands. A trend of 18O enrichment in mollusk shells points to an increase in bottom-water salinity during the Vityazevian to Kalamitian transgressions (??? 7000 to 5700??14C yr BP) due to a more open connection with the Mediterranean, while a pronounced increase in polyhaline species abundance is established during</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6645326','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6645326"><span id="translatedtitle">Correlation of <span class="hlt">sea</span> <span class="hlt">level</span> falls interpreted from atoll stratigraphy with turbidites in adjacent basins</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lincoln, J.M. )</p> <p>1990-05-01</p> <p>Past <span class="hlt">sea</span> <span class="hlt">levels</span> can be derived from any atoll subsurface sediments deposited at or near <span class="hlt">sea</span> <span class="hlt">level</span> by determining the ages of deposition and correcting the present depths to the sediments for subsidence of the underlying edifice since the times of deposition. A <span class="hlt">sea</span> <span class="hlt">level</span> curve constructed by this method consists of discontinuous segments, each corresponding to a period of rising relative <span class="hlt">sea</span> <span class="hlt">level</span> and deposition of a discrete sedimentary package. Discontinuities in the <span class="hlt">sea</span> <span class="hlt">level</span> curve derived by this method correspond to relative <span class="hlt">sea</span> <span class="hlt">level</span> falls and stratigraphic hiatuses in the atoll subsurface. During intervals of relative <span class="hlt">sea</span> <span class="hlt">level</span> fall an atoll emerges to become a high limestone island. <span class="hlt">Sea</span> <span class="hlt">level</span> may fluctuate several times during a period of atoll emergence to become a high limestone island. <span class="hlt">Sea</span> <span class="hlt">level</span> may fluctuate several times during a period of atoll emergence without depositing sediments on top of the atoll. Furthermore, subaerial erosion may remove a substantial part of the depositional record of previous <span class="hlt">sea</span> <span class="hlt">level</span> fluctuations. For these reasons the authors must look to the adjacent basins to complement the incomplete record of <span class="hlt">sea</span> <span class="hlt">level</span> change recorded beneath atolls. During lowstands of <span class="hlt">sea</span> <span class="hlt">level</span>, faunas originally deposited near <span class="hlt">sea</span> <span class="hlt">level</span> on an atoll may be eroded and redeposited as turbidites in deep adjacent basins. Three such turbidites penetrated during deep-<span class="hlt">sea</span> drilling at Sites 462 and 315 in the central Pacific correlate well with a late Tertiary <span class="hlt">sea</span> <span class="hlt">level</span> curve based on biostratigraphic ages and {sup 87}Sr/{sup 86}Sr chronostratigraphy for core from Enewetak Atoll in the northern Marshall Islands. Further drilling of the archipelagic aprons adjacent to atolls will improve the <span class="hlt">sea</span> <span class="hlt">level</span> history that may be inferred from atoll stratigraphy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7043S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7043S"><span id="translatedtitle"><span class="hlt">Sea</span> <span class="hlt">level</span> rise of semi-enclosed basins: deviation of Adriatic and Baltic <span class="hlt">sea</span> <span class="hlt">level</span> from the mean global value.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scarascia, Luca; Lionello, Piero</p> <p>2015-04-01</p> <p>Future <span class="hlt">sea</span> <span class="hlt">level</span> rise (SL), which represents today one of the major threats that are caused by climate change, will not be uniform. Regional differences are crucial for 40% of the world population, which is located in the coastal zone. To explore the mechanisms linking regional SL to climate variables is very important in order to provide reliable future projections. This study focuses on two semi-enclosed basins, the Adriatic and Baltic <span class="hlt">Sea</span> and investigates the deviation of their SL from the mean global value. In fact, past deviations of the SL of these two basins from the global value have been observed and can be attributed to large scale factors (such as teleconnections) and regional factors, such as the inverse barometric effect, the wind stress, the thermosteric and halosteric effects. The final goal of this work is to assess to which extent the Adriatic and Baltic SL will depart from the mean global value in the next decades and at the end of 21st century. This is achieved by analyzing deviations of the mean SL of the Baltic and Adriatic <span class="hlt">Sea</span> from the global mean SL during the 20th century and investigating which factors can explain such deviations. A multivariate linear regression model is built and used to describe the link between three large scale climate variables which are used as predictors (mean <span class="hlt">sea</span> <span class="hlt">level</span> pressure, surface air temperature and precipitation), and the regional SL deviation (the predictand), computed as the difference between the regional and the global SL. At monthly scale this linear regression model provides a good reconstruction of the past variability in the cold season during which it explains 60%-70% of the variance. Summer reconstruction is substantially less successful and it represents presently the main limit of the model skill. This linear regression model, forced by predictors extracted from CMIP5 multi-model simulations, is used to provide projections of SL in the Adriatic and Baltic <span class="hlt">Sea</span>. On the basis of the projections</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1410078H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1410078H"><span id="translatedtitle">The Semiannual Oscillation of Southern Ocean <span class="hlt">Sea</span> <span class="hlt">Level</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hibbert, A.</p> <p>2012-04-01</p> <p>The atmospheric Semiannual Oscillation (SAO) is a half-yearly wave in mean <span class="hlt">sea</span> <span class="hlt">level</span> air pressure, which exhibits equinoctial maxima between 45°S and 50°S and solstitial maxima between 55°S and 65°s, with a phase reversal occurring at around 60°S. Its existence has been attributed to a phase difference in the annual temperature cycle between mid- and high-latitudes which sets up meridional temperature and pressure gradients that are largest during September and March, enhancing atmospheric baroclinicity and inducing equinoctial maxima in the Southern Hemisphere Westerlies. In this study, we use harmonic analysis of atmospheric and oceanic Southern Ocean datasets to show that this atmospheric SAO induces oceanic counterparts in <span class="hlt">sea</span> <span class="hlt">level</span> and circumpolar transport. This aspect of atmosphere-ocean interaction is particularly important, given the capacity of the Antarctic Circum