High-resolution tide projections reveal extinction threshold in response to sea-level rise

<div> <div> <div> <p>The current global climate models, which are often used in inter-comparison projects, have a large variety in their spatial resolution. For most climate models, the resolution of the ocean grid does not allow to resolve mesoscale processes such as ocean eddies. Current sea level projections are based on these coarse climate models, but might have biases (either positive or negative) in these projections since mesoscale processes are parameterised.</p> <p>Here we investigate the differences in future Caribbean sea level rise using a centennial simulation of a high- and low-resolution version of the Community Earth System Model under the same anthropogenic forcing. In the high-resolution version of the model mesoscale processes are resolved. Locally, we find a decrease of 7.2 cm in sea level extremes over a 100-year period in the high-resolution version; this decrease is almost absent in the low-resolution version. This local decrease in sea level extremes is related to ocean eddies, which are not resolved in the low-resolution version, hence explaining the different sea level response between the models. When comparing modelled sea level trends to observed sea level trends over the past 25 years, we find a reasonable agreement between observations and the high-resolution model. However, for the low-resolution model and some of the preliminary CMIP6 model output, there is a substantial mismatch between the observed- and modelled sea level trends.</p> <p>By analysing model output from two different resolutions of the same climate model, we find that the sea level response in the Caribbean Sea is resolution-dependent. As a result, not resolving mesoscale processes in climate models can locally result in overestimations of future sea level rise projections.</p> </div> </div> </div>

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An evaluation of the surface climatology over the Totten region (Antarctica) using COSMO-CLM2

10.5194/egusphere-egu2020-5211 ◽

2020 ◽

Author(s):

Samuel Helsen ◽

Sam Vanden Broucke ◽

Alexandra Gossart ◽

Niels Souverijns ◽

Nicole van Lipzig

Keyword(s):

High Resolution ◽

Sea Level Rise ◽

Sea Level ◽

Climate Models ◽

Climate Model ◽

Ice Sheet ◽

Ocean Model ◽

Precipitation Pattern ◽

Outlet Glacier ◽

The Antarctic

<p>The Totten glacier is a highly dynamic outlet glacier, situated in E-Antarctica, that contains a potential sea level rise of about 3.5 meters. During recent years, this area has been influenced by sub-shelf intrusion of warm ocean currents, contributing to higher basal melt rates. Moreover, most of the ice over this area is grounded below sea level, which makes the ice shelf potentially vulnerable to the marine ice sheet instability mechanism. It is expected that, as a result of climate change, the latter mechanisms may contribute to significant ice losses in this region within the next decades, thereby contributing to future sea level rise. Up to now, most studies have been focusing on sub-shelf melt rates and the influence of the ocean, with much less attention for atmospheric processes (often ignored), which also play a key-role in determining the climatic conditions over this region. For example: surface melt is important because it contributes to hydrofracturing, a process that may lead to ice cliff instabilities. Also precipitation is an important atmospheric process, since it determines the input of mass to the ice sheet and contributes directly to the surface mass balance. In order to perform detailed studies on these processes, we need a well-evaluated climate model that represents all these processes well. Recently, the COSMO-CLM<sup>2</sup> (CCLM<sup>2</sup>) model was adapted to the climatological conditions over Antarctica. The model was evaluated by comparing a 30 year Antarctic-wide hindcast run (1986-2016) at 25 km resolution with meteorological observational products (Souverijns et al., 2019). It was shown that the model performance is comparable to other state-of-the-art regional climate models over the Antarctic region. We now applied the CCLM<sup>2</sup> model in a regional configuration over the Totten glacier area (E-Antarctica) at 5 km resolution and evaluated its performance over this region by comparing it to climatological observations from different stations. We show that the performance for temperature in the high resolution run is comparable to the performance of the Antarctic-wide run. Precipitation is, however, overestimated in the high-resolution run, especially over dome structures (Law-Dome). Therefore, we applied an orographic smoothening, which clearly improves the precipitation pattern with respect to observations. Wind speed is overestimated in some places, which is solved by increasing the surface roughness. This research frames in the context of the PARAMOUR project. Within PARAMOUR, CCLM<sup>2 </sup>is currently being coupled to an ocean model (NEMO) and an ice sheet model (f.ETISh/BISICLES) in order to understand decadal predictability over this region.</p>

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Sea Level Rise Scenario for 2100 A.D. in the Heritage Site of Pyrgi (Santa Severa, Italy)

10.20944/preprints201910.0202.v1 ◽

2019 ◽

Author(s):

Marco Anzidei ◽

Fawzi Doumaz ◽

Antonio Vecchio ◽

Enrico Serpelloni ◽

Luca Pizzimenti ◽

...

Keyword(s):

High Resolution ◽

Sea Level Rise ◽

Sea Level ◽

Storm Surges ◽

Coastal Zones ◽

Heritage Sites ◽

Historical Structures ◽

Vertical Land Motion ◽

Climatic Scenarios ◽

The Mediterranean

Sea level rise is one of the main factor of risk for the preservation of cultural heritage sites located along the coasts of the Mediterranean basin. Coastal retreat, erosion and storm surges are yet posing serious threats to archaeological and historical structures built along the coastal zones of this region. In order to assess the coastal changes by the end of 2100 under an expected sea level rise of about 1 m, a detailed determination of the current coastline position and the availability of high resolution DSM, is needed. This paper focuses on the use of very high-resolution UAV imagery for the generation of ultra-high resolution mapping of the coastal archaeological area of Pyrgi, near Rome (Italy). The processing of the UAV imagery resulted in the generation of a DSM and an orthophoto, with an accuracy of 1.94 cm/pixel. The integration of topographic data with two sea level rise projections in the IPCC AR5 2.6 and 8.5 climatic scenarios for this area of the Mediterranean, were used to map sea level rise scenarios for 2050 and 2100. The effects of the Vertical Land Motion (VLM) as estimated from two nearby continuous GPS stations located as much as close to the coastline, were included in the analysis. Relative sea level rise projections provide values at 0.30±0.15 cm by 2050 and 0.56±0.22 by 2100, for the IPCC AR5 8.5 scenarios and at 0.13±0.05 cm by 2050 and 0.17±0.22 by 2100, for the IPCC AR5 2.6 scenario. These values of rise will correspond to a potential beach loss between 12.6% and 23.5% in 2100 for RCP 2.6 and 8.5 scenarios, respectively, while during the highest tides the beach will be reduced up to 46.4%. With these sea level rise scenarios, Pyrgi with its nearby Etruscan temples and the medieval castle of Santa Severa will be soon exposed to high risk of marine flooding, especially during storm surges, thus requiring suitable adaptation strategies.

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Coastal sea level rise at Senetosa (Corsica) during the Jason altimetry missions

Ocean Science ◽

10.5194/os-16-1165-2020 ◽

2020 ◽

Vol 16 (5) ◽

pp. 1165-1182 ◽

Cited By ~ 1

Author(s):

Yvan Gouzenes ◽

Fabien Léger ◽

Anny Cazenave ◽

Florence Birol ◽

Pascal Bonnefond ◽

...

Keyword(s):

High Resolution ◽

Sea Level Rise ◽

Sea Level ◽

Leading Edge ◽

Satellite System ◽

Careful Examination ◽

Coastal Zones ◽

Coastal Sea ◽

Potential Contributor ◽

Global Navigation Satellite

Abstract. In the context of the ESA Climate Change Initiative project, we are engaged in a regional reprocessing of high-resolution (20 Hz) altimetry data of the classical missions in a number of the world's coastal zones. It is done using the ALES (Adaptive Leading Edge Subwaveform) retracker combined with the X-TRACK system dedicated to improve geophysical corrections at the coast. Using the Jason-1 and Jason-2 satellite data, high-resolution, along-track sea level time series have been generated, and coastal sea level trends have been computed over a 14-year time span (from July 2002 to June 2016). In this paper, we focus on a particular coastal site where the Jason track crosses land, Senetosa, located south of Corsica in the Mediterranean Sea, for two reasons: (1) the rate of sea level rise estimated in this project increases significantly in the last 4–5 km to the coast compared to what is observed further offshore, and (2) Senetosa is the calibration site for the TOPEX/Poseidon and Jason altimetry missions, which are equipped for that purpose with in situ instrumentation, in particular tide gauges and a Global Navigation Satellite System (GNSS) antenna. A careful examination of all the potential errors that could explain the increased rate of sea level rise close to the coast (e.g., spurious trends in the geophysical corrections, imperfect inter-mission bias estimate, decrease of valid data close to the coast and errors in waveform retracking) has been carried out, but none of these effects appear able to explain the trend increase. We further explored the possibility that it results from real physical processes. Change in wave conditions was investigated, but wave setup was excluded as a potential contributor because the magnitude was too low and too localized in the immediate vicinity of the shoreline. A preliminary model-based investigation about the contribution of coastal currents indicates that it could be a plausible explanation of the observed change in sea level trend close to the coast.

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Submarine melt parameterization for a Greenland glacial system model

10.5194/tc-2016-284 ◽

2017 ◽

Author(s):

Johanna Beckmann ◽

Mahé Perrette ◽

Andrey Ganopolski

Keyword(s):

High Resolution ◽

Sea Level Rise ◽

Sea Level ◽

Greenland Ice Sheet ◽

3D Models ◽

Model Parameters ◽

Computationally Efficient ◽

Plume Model ◽

Alternative Approach ◽

Quantitative Manner

Abstract. Two hundreds of marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and play an important role in the Greenland ice sheet mass loss observed since the mid 1990s. Submarine melt plays a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase and outlet glaciers will retreat, contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise is hampered by the necessity to use extremely high resolution of the order of a few hundred meters both for modelling of the outlet glaciers and as well as coupling them with high resolution 3D ocean models. In addition fjord bathymetry data are mostly missing or are inaccurate (errors of several 100s of meters), which questions the benefit of using computational expensive 3D models for future predictions. Here we propose an alternative approach based on using of computationally efficient parameterization of submarine melt based on turbulent plume theory. We show that such parameterization is in a reasonable agreement with several available modeling studies. We performed a suit of experiments to analyse sensitivity of these parameterizations to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behaviour as 3D gerneral circulation models. To match results of the 3D models in a quantitative manner, a scaling factor in the order of one is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the parameterization of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume model for simulating the submarine melting of real glaciers in Greenland.

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Local Sea-Level Rise Caused by Climate Change in the Northwest Pacific Marginal Seas Using Dynamical Downscaling

Frontiers in Marine Science ◽

10.3389/fmars.2021.620570 ◽

2021 ◽

Vol 8 ◽

Author(s):

Yong-Yub Kim ◽

Bong-Gwan Kim ◽

Kwang Young Jeong ◽

Eunil Lee ◽

Do-Seong Byun ◽

...

Keyword(s):

High Resolution ◽

Sea Level Rise ◽

Sea Level ◽

Climate Models ◽

Dynamical Downscaling ◽

The Yellow Sea ◽

Northwest Pacific ◽

Tidal Amplitude ◽

Marginal Seas ◽

Rcp 8.5

Global climate models (GCMs) have limited capacity in simulating spatially non-uniform sea-level rise owing to their coarse resolutions and absence of tides in the marginal seas. Here, regional ocean climate models (RCMs) that consider tides were used to address these limitations in the Northwest Pacific marginal seas through dynamical downscaling. Four GCMs that drive the RCMs were selected based on a performance evaluation along the RCM boundaries, and the latter were validated by comparing historical results with observations. High-resolution (1/20°) RCMs were used to project non-uniform changes in the sea-level under intermediate (RCP 4.5) and high-end emissions (RCP 8.5) scenarios from 2006 to 2100. The predicted local sea-level rise was higher in the East/Japan Sea (EJS), where the currents and eddy motions were active. The tidal amplitude changes in response to sea-level rise were significant in the shallow areas of the Yellow Sea (YS). Dynamically downscaled simulations enabled the determination of practical sea-level rise (PSLR), including changes in tidal amplitude and natural variability. Under RCP 8.5 scenario, the maximum PSLR was ∼85 cm in the YS and East China Sea (ECS), and ∼78 cm in the EJS. The contribution of natural sea-level variability changes in the EJS was greater than that in the YS and ECS, whereas changes in the tidal contribution were higher in the YS and ECS. Accordingly, high-resolution RCMs provided spatially different PSLR estimates, indicating the importance of improving model resolution for local sea-level projections in marginal seas.

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Geomorphology of Canyon Outlets in Zrmanja River Estuary and Its Effect on the Holocene Flooding of Semi-enclosed Basins (the Novigrad and Karin Seas, Eastern Adriatic)

Water ◽

10.3390/w12102807 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2807

Author(s):

Ozren Hasan ◽

Slobodan Miko ◽

Dea Brunović ◽

George Papatheodorou ◽

Dimitris Christodolou ◽

...

Keyword(s):

High Resolution ◽

Sea Level Rise ◽

Sea Level ◽

Geophysical Methods ◽

River Estuary ◽

Side Scan Sonar ◽

The Holocene ◽

Karst Environment ◽

Gis Environment ◽

Holocene Sea Level

Detailed multi-beam bathymetry, sub-bottom acoustic, and side-scan sonar observations of submerged canyons with tufa barriers were used to characterize the Zrmanja River karst estuary on the eastern Adriatic coast, Croatia. This unique karst environment consists of two submerged karst basins (Novigrad Sea and Karin Sea) that are connected with river canyons named Novsko Ždrilo and Karinsko Ždrilo. The combined use of high-resolution geophysical data with legacy topography and bathymetry data in a GIS environment allowed for the description and interpretation of this geomorphological setting in relation to the Holocene sea-level rise. The tufa barriers had a predominant influence on the Holocene flooding dynamics of the canyons and karst basins. Here, we describe the possible river pathways from the basins during the lowstand and the formation of a lengthening estuary during the Holocene sea-level rise. Based on the analyzed morphologies and the relative sea-level curve for the Adriatic Sea, the flooding of the Novsko Ždrilo occurred 9200 years before present (BP) and Karinsko Ždrilo was flooded after 8400 years BP. The combination of high-resolution geophysical methods gave an accurate representation of the karst estuarine seafloor and the flooding of semi-isolated basins due to sea-level rise.

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Improving Methodology for High-Resolution Reconstruction of Sea-Level Rise and Neotectonics by Paleoecological Analysis and AMS 14C Dating of Basal Peats

Quaternary Research ◽

10.1006/qres.1997.1938 ◽

1998 ◽

Vol 49 (1) ◽

pp. 72-85 ◽

Cited By ~ 46

Author(s):

Torbjörn E. Törnqvist ◽

Mark H.M. van Ree ◽

Ron van 't Veer ◽

Bas van Geel

Keyword(s):

High Resolution ◽

Ground Water ◽

Sea Level Rise ◽

Water Level ◽

Sea Level ◽

Small Sample ◽

Water Levels ◽

Ground Water Level ◽

Specific Level ◽

High Resolution Reconstruction

Sea-level research in several submerging coastal regions has traditionally been based on 14C dating of basal peats that overlie a compaction-free substratum and can be related to paleo-(ground)water levels. Provided that an unequivocal relationship between (ground)water level and sea level can be assumed, this approach contains two sources of uncertainty: (1) the paleoenvironmental interpretation of samples is usually based on inherently inaccurate macroscopic descriptions in the field, and (2) 14C ages of bulk peat samples may be erroneous as a result of contamination. Due to the uncertainties in both the altitude and the age—the two crucial sources of evidence necessary to arrive at accurate sea-level curves—sea-level index points are therefore represented by considerable, but typically not quantified, error boxes. Accelerator mass spectrometry (AMS) opens new perspectives for this type of sea-level research, as illustrated by a paleoecological and AMS 14C study of basal peats from a small study area in the Rhine–Meuse Delta (The Netherlands), where previous (conventional) work revealed highly problematic results. A detailed macrofossil analysis has two purposes: (1) an inferred paleoecological succession indicates a relatively accurate level of paludification of the site, and hence rise of the (ground)water level; (2) suitable macrofossils from that specific level are then selected for AMS 14C dating. In spite of very small sample sizes, our results are consistent and indicate that this approach can constitute a step forward in high-resolution reconstruction of sea-level rise. The new results further enable a revision of Holocene (ground)water gradient lines for the Rhine–Meuse Delta. A knickpoint in these gradient lines can be related to the effect of faulting. This approach therefore also has considerable potential to unravel and quantify neotectonic activity in submerging coastal settings.

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Sea Level Rise Scenario for 2100 A.D. in the Heritage Site of Pyrgi (Santa Severa, Italy)

Journal of Marine Science and Engineering ◽

10.3390/jmse8020064 ◽

2020 ◽

Vol 8 (2) ◽

pp. 64 ◽

Cited By ~ 3

Author(s):

Marco Anzidei ◽

Fawzi Doumaz ◽

Antonio Vecchio ◽

Enrico Serpelloni ◽

Luca Pizzimenti ◽

...

Keyword(s):

High Resolution ◽

Sea Level Rise ◽

Sea Level ◽

Storm Surges ◽

Coastal Zones ◽

Dune System ◽

Intergovernmental Panel ◽

Historical Structures ◽

Vertical Land Motion ◽

The Mediterranean

Sea level rise is one of the main risk factors for the preservation of cultural heritage sites located along the coasts of the Mediterranean basin. Coastal retreat, erosion, and storm surges are posing serious threats to archaeological and historical structures built along the coastal zones of this region. In order to assess the coastal changes by the end of 2100 under the expected sea level rise of about 1 m, we need a detailed determination of the current coastline position based on high resolution Digital Surface Models (DSM). This paper focuses on the use of very high-resolution Unmanned Aerial Vehicles (UAV) imagery for the generation of ultra-high-resolution mapping of the coastal archaeological area of Pyrgi, Italy, which is located near Rome. The processing of the UAV imagery resulted in the generation of a DSM and an orthophoto with an accuracy of 1.94 cm/pixel. The integration of topographic data with two sea level rise projections in the Intergovernmental Panel on Climate Change (IPCC) AR5 2.6 and 8.5 climatic scenarios for this area of the Mediterranean are used to map sea level rise scenarios for 2050 and 2100. The effects of the Vertical Land Motion (VLM) as estimated from two nearby continuous Global Navigation Satellite System (GNSS) stations located as close as possible to the coastline are included in the analysis. Relative sea level rise projections provide values at 0.30 ± 0.15 cm by 2050 and 0.56 ± 0.22 cm by 2100 for the IPCC AR5 8.5 scenarios and at 0.13 ± 0.05 cm by 2050 and 0.17 ± 0.22 cm by 2100, for the IPCC Fifth Assessment Report (AR5) 2.6 scenario. These values of rise correspond to a potential beach loss between 12.6% and 23.5% in 2100 for Representative Concentration Pathway (RCP) 2.6 and 8.5 scenarios, respectively, while, during the highest tides, the beach will be provisionally reduced by up to 46.4%. In higher sea level positions and storm surge conditions, the expected maximum wave run up for return time of 1 and 100 years is at 3.37 m and 5.76 m, respectively, which is capable to exceed the local dune system. With these sea level rise scenarios, Pyrgi with its nearby Etruscan temples and the medieval castle of Santa Severa will be exposed to high risk of marine flooding, especially during storm surges. Our scenarios show that suitable adaptation and protection strategies are required.

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