Quantifying rates of coastal subsidence since the last interglacial and the role of sediment loading

2013 ◽  
Vol 111 ◽  
pp. 296-308 ◽  
Author(s):  
Alexander R. Simms ◽  
John B. Anderson ◽  
Regina DeWitt ◽  
Kurt Lambeck ◽  
Anthony Purcell
Keyword(s):  
Sediment Loading ◽  
Last Interglacial

scholarly journals Towards assessing the influence of sediment loading on Last Interglacial sea level

2019 ◽  
Vol 220 (1) ◽  
pp. 384-392
Author(s):  
T Pico
Keyword(s):  
Sea Level ◽  
Tectonic Uplift ◽  
Sediment Loading ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Isostatic Adjustment ◽  
Uplift Rates ◽  
History Of ◽  
The Impact ◽  
The Last Glacial

SUMMARY Locally, the elevation of last interglacial (LIG; ∼122 ka) sea level markers is modulated by processes of vertical displacement, such as tectonic uplift or glacial isostatic adjustment, and these processes must be accounted for in deriving estimates of global ice volumes from geological sea level records. The impact of sediment loading on LIG sea level markers is generally not accounted for in these corrections, as it is assumed that the impact is negligible except in extremely high depositional settings, such as the world's largest river deltas. Here we perform a generalized test to assess the extent to which sediment loading may impact global variability in the present-day elevation of LIG sea level markers. We numerically simulate river sediment deposition using a diffusive model that incorporates a migrating shoreline to construct a global history of sedimentation over the last glacial cycle. We then calculate sea level changes due to this sediment loading using a gravitationally self-consistent model of glacial isostatic adjustment, and compare these predictions to a global compilation of LIG sea level data. We perform a statistical analysis, which accounts for spatial autocorrelation, across a global compilation of 1287 LIG sea level markers. Though limited by uncertainties in the LIG sea level database and the precise history of river deposition, this analysis suggests there is not a statistically significant global signal of sediment loading in LIG sea level markers. Nevertheless, at sites where LIG sea level markers have been measured, local sea level predicted using our simulated sediment loading history is perturbed up to 16 m. More generally, these predictions establish the relative sensitivity of different regions to sediment loading. Finally, we consider the implications of our results for estimates of tectonic uplift rates derived from LIG marine terraces; we predict that sediment loading causes 5–10 m of subsidence over the last glacial cycle at specific locations along active margin regions such as California and Barbados, where deriving long-term tectonic uplift rates from LIG shorelines is a common practice.

scholarly journals The role of ocean thermal expansion in Last Interglacial sea level rise

2011 ◽  
Vol 38 (14) ◽  
pp. n/a-n/a ◽  
Author(s):  
Nicholas P. McKay ◽  
Jonathan T. Overpeck ◽  
Bette L. Otto-Bliesner
Keyword(s):  
Thermal Expansion ◽  
Sea Level Rise ◽  
Sea Level ◽  
Last Interglacial

Terminating the Last Interglacial: The Role of Ice Sheet–Climate Feedbacks in a GCM Asynchronously Coupled to an Ice Sheet Model

2011 ◽  
Vol 25 (6) ◽  
pp. 1871-1882 ◽  
Author(s):  
Adam R. Herrington ◽  
Christopher J. Poulsen
Keyword(s):  
Ice Sheet ◽  
Stationary Wave ◽  
Rapid Expansion ◽  
Laurentide Ice Sheet ◽  
Interglacial Period ◽  
Climate Feedbacks ◽  
Last Interglacial ◽  
Ice Volume ◽  
Ice Cap

Abstract Climatic deterioration in northeastern Canada following the last interglacial resulted in the formation and abrupt expansion of the Laurentide Ice Sheet. However, the physical mechanisms leading to rapid ice sheet expansion are not well understood. Here, the authors report on experiments using an ice sheet model asynchronously coupled to a GCM to investigate the role of ice sheet–climate feedbacks in terminating the last interglacial period. In agreement with simpler models, the experiments indicate that a specific type of ice–albedo feedback, the small ice cap instability, is the dominant process controlling rapid expansion of the Laurentide Ice Sheet. As ice elevations increase in northeastern Canada, a stationary wave forms and strengthens over the Laurentide Ice Sheet, which acts to hinder further expansion of the ice margin and reduce the effect of the small ice cap instability. The sensitivity of these feedbacks to ice topography results in a reduction in simulated ice volume when the communication interval between the GCM and ice sheet model is lengthened since this permits larger gains in ice elevation between GCM updates and biases the simulation toward a stronger stationary wave feedback. The shortest communication interval (500 yr) leads to a Laurentide ice volume of 6 × 106 km3 in 10 kyr, which is less than ice volume estimates based on the geological record but is a substantial improvement over previous GCM studies. The authors discuss potential improvements to the asynchronous coupling scheme that would more accurately resolve ice sheet–climate feedbacks, potentially leading to greater simulated ice volume.

scholarly journals Warm Greenland during the last interglacial: the role of regional changes in sea ice cover

2016 ◽  
Vol 12 (10) ◽  
pp. 2011-2031 ◽  
Author(s):  
Niklaus Merz ◽  
Andreas Born ◽  
Christoph C. Raible ◽  
Thomas F. Stocker
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Labrador Sea ◽  
Last Interglacial ◽  
Atlantic Sector ◽  
Nordic Seas ◽  
Proxy Records ◽  
Ice Retreat ◽  
Sea Ice Retreat

Abstract. The last interglacial, also known as the Eemian, is characterized by warmer than present conditions at high latitudes. This is implied by various Eemian proxy records as well as by climate model simulations, though the models mostly underestimate the warming with respect to proxies. Simulations of Eemian surface air temperatures (SAT) in the Northern Hemisphere extratropics further show large variations between different climate models, and it has been hypothesized that this model spread relates to diverse representations of the Eemian sea ice cover. Here we use versions 3 and 4 of the Community Climate System Model (CCSM3 and CCSM4) to highlight the crucial role of sea ice and sea surface temperatures changes for the Eemian climate, in particular in the North Atlantic sector and in Greenland. A substantial reduction in sea ice cover results in an amplified atmospheric warming and thus a better agreement with Eemian proxy records. Sensitivity experiments with idealized lower boundary conditions reveal that warming over Greenland is mostly due to a sea ice retreat in the Nordic Seas. In contrast, sea ice changes in the Labrador Sea have a limited local impact. Changes in sea ice cover in either region are transferred to the overlying atmosphere through anomalous surface energy fluxes. The large-scale spread of the warming resulting from a Nordic Seas sea ice retreat is mostly explained by anomalous heat advection rather than by radiation or condensation processes. In addition, the sea ice perturbations lead to changes in the hydrological cycle. Our results consequently imply that both temperature and snow accumulation records from Greenland ice cores are sensitive to sea ice changes in the Nordic Seas but insensitive to sea ice changes in the Labrador Sea. Moreover, the simulations suggest that the uncertainty in the Eemian sea ice cover accounts for 1.6 °C of the Eemian warming at the NEEM ice core site. The estimated Eemian warming of 5 °C above present day based on the NEEM δ15N record can be reconstructed by the CCSM4 model for the scenario of a substantial sea ice retreat in the Nordic Seas combined with a reduced Greenland ice sheet.

scholarly journals Geological processes and the management of groundwater resources in coastal areas

2003 ◽  
Vol 82 (1) ◽  
pp. 31-40 ◽  
Author(s):  
H. Kooi ◽  
J. Groen
Keyword(s):  
Sea Level ◽  
Groundwater Resources ◽  
Sea Level Change ◽  
Coastal Areas ◽  
Shallow Aquifer ◽  
Sediment Loading ◽  
Level Change ◽  
Geological Processes ◽  
And Sea Level

AbstractIn this contribution, a case is made for the significance of sedimentation and sea-level change for groundwater management of coastal areas. In groundwater practice these geological processes are rarely considered. The role of sediment loading in causing anomalous fluid pressures and flow fields in relatively shallow aquifer systems is discussed and illustrated via both case studies and generic modelling studies. The role of sea-level changes in controlling current salinity distributions is discussed likewise. Central in the discussion is the concept of memory of groundwater systems, which provides the basic reason why processes that were operative in the geological past are still of relevance today. It is argued and shown that awareness and knowledge of the influence of sediment loading and sea level change on current hydrological conditions can lead to improved characterization of the distribution of hydraulic parameters and of the distribution of water quality in coastal areas. This improved characterization, in turn, serves to enhance the validity of impact assessment studies for the long-term development and management of those areas.

Denitrification and the Role of Macrofauna Across Estuarine Gradients in Nutrient and Sediment Loading

2020 ◽  
Vol 43 (6) ◽  
pp. 1394-1405
Author(s):  
Theresa A. O’Meara ◽  
Judi E. Hewitt ◽  
Simon F. Thrush ◽  
Emily J. Douglas ◽  
Andrew M. Lohrer
Keyword(s):  
Sediment Loading ◽  
Estuarine Gradients

scholarly journals Simulating the Last Interglacial Greenland stable water isotope peak: The role of Arctic sea ice changes

2018 ◽  
Vol 198 ◽  
pp. 1-14 ◽  
Author(s):  
Irene Malmierca-Vallet ◽  
Louise C. Sime ◽  
Julia C. Tindall ◽  
Emilie Capron ◽  
Paul J. Valdes ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Last Interglacial ◽  
Isotope Peak ◽  
Arctic Sea ◽  
Water Isotope

The impact of orbital forcing on the Arctic climate during the Last Interglacial simulated by the IPSL-CM6A-LR model

2020 ◽  
Author(s):  
Marie Sicard ◽  
Masa Kageyama ◽  
Pascale Braconnot ◽  
Sylvie Charbit
Keyword(s):  
Solar Radiation ◽  
Sea Ice ◽  
Arctic Sea Ice ◽  
Arctic Climate ◽  
The Arctic ◽  
Orbital Forcing ◽  
Last Interglacial ◽  
Arctic Sea ◽  
The Impact

<p>The Last Interglacial (129 – 116 ka BP) is a time period with a strong orbital forcing which leads to a different seasonal and latitudinal distribution of insolation compared to the present. In particular, these changes amplify the Arctic climate seasonality. They induce warmer summers and colder winters in the high latitudes of the Northern Hemisphere. Such surface conditions favour a huge retreat of the arctic sea ice cover.<br>In this study, we try to understand how this solar radiation anomaly spreads through the surface and impacts the seasonal arctic sea ice. Using IPSL-CM6A-LR model outputs, we decompose the surface energy budget to identify the role of atmospheric and oceanic key processes beyond 60°N and its changes compared to pre-industrial. We show that solar radiation anomaly is greatly reduced when it reaches the Earth’s surface, which emphasizes the role of clouds and water vapor transport.<br>The results are also compared to other PMIP4-CMIP6 model simulations. We would like to thank PMIP participants for producing and making available their model outputs.</p>

scholarly journals Warm Greenland during the last interglacial: the role of regional changes in sea ice cover

2016 ◽  
Author(s):  
Niklaus Merz ◽  
Andreas Born ◽  
Christoph C. Raible ◽  
Thomas F. Stocker
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Labrador Sea ◽  
Last Interglacial ◽  
Atlantic Sector ◽  
Climate System Model ◽  
Nordic Seas ◽  
Ice Retreat ◽  
Sea Ice Retreat

Abstract. The last interglacial, the Eemian, is characterized by warmer than present conditions at high latitudes and is therefore often considered as a possible analogue for the climate in the near future. Simulations of Eemian surface air temperatures (SAT) in the Northern Hemisphere, however, show large variations between different climate models and it has been hypothesized that this model spread relates to diverse representations of the Eemian sea ice cover. Here we use versions 3 and 4 of the Community Climate System Model (CCSM3 and CCSM4), to highlight the crucial role of sea ice and sea surface temperatures during the Eemian, in particular for SAT in the North Atlantic sector and in Greenland. A substantial reduction in sea ice cover results in an amplified atmospheric warming and, thus, a better agreement with Eemian proxy records. Sensitivity experiments with idealized lower boundary conditions reveal that warming over Greenland is mostly due to a sea ice retreat in the Nordic Seas. In contrast, sea ice changes in the Labrador Sea have a limited local impact. Changes in sea ice cover in either region are transferred to the overlying atmosphere through anomalous surface energy fluxes. The large-scale warming simulated for the sea ice retreat in the Nordic Seas further relates to anomalous heat advection. Diabatic processes play a secondary role, yet distinct changes in the hydrological cycle are possible. Our results imply that temperature and accumulation records from Greenland ice cores are sensitive to sea ice changes in the Nordic Seas but insensitive to sea ice changes in the Labrador Sea. Moreover, our simulations suggest that the uncertainty in the Eemian sea ice cover accounts for 1.6 °C of the Eemian warming at the NEEM ice core site. The estimated Eemian warming of 5 °C above present-day based on the NEEM δ15N record can be reconstructed by the CCSM4 model for the scenario of a substantial sea ice retreat in the Nordic Seas combined with a reduced Greenland ice sheet.

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