scholarly journals Coastal Sea Level rise at Senetosa (Corsica) during the Jason altimetry missions

2020 ◽  
Author(s):  
Yvan Gouzenes ◽  
Fabien Léger ◽  
Anny Cazenave ◽  
Florence Birol ◽  
Pascal Bonnefond ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Level Rise ◽  
Sea Level ◽  
Leading Edge ◽  
Careful Examination ◽  
Coastal Zones ◽  
Small Magnitude ◽  
Coastal Sea ◽  
Potential Contributor ◽  
Set Up

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 coastal zones worldwide. 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 & 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 a 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, equipped for that purpose with in situ instrumentation, in particular tide gauges and GNSS antennas. 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 intermission 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 it results from real physical processes. Change in wave conditions was investigated but wave set up was excluded as a potential contributor because of too small magnitude and too localized in the immediate vicinity of the shoreline. 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.

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

Ocean Science ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 1165-1182 ◽  
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.

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

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.

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

2020 ◽  
Vol 8 (2) ◽  
pp. 64 ◽  
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.

Observed coastal sea level changes in Southeast Asia from retracked altimetry over 2002-present

2020 ◽  
Author(s):  
Yvan Gouzènes ◽  
Fabien Léger ◽  
Anny Cazenave ◽  
Florence Birol ◽  
Marcello Passaro ◽  
...  
Keyword(s):  
Time Series ◽  
Southeast Asia ◽  
Sea Level ◽  
Processing System ◽  
Leading Edge ◽  
Open Ocean ◽  
Small Scale ◽  
Coastal Zones ◽  
Sea Level Changes ◽  
Coastal Sea

<p>We present results of contemporary coastal sea level changes along the coasts of different<br>regions of Southeast Asia derived from a dedicated reprocessing of satellite altimetry data.<br>This work is performed in the context of the ESA ‘Climate Change Initiative’ sea level project<br>dedicated to provide altimetry-based sea level time series in the world coastal zones. Here is<br>focus on Southeast Asian Seas. High-frequency (20 Hz) sea level data from the Jason-1,<br>Jason-2 and Jason-3 missions are considered. The data are first retracked using the ALES<br>adaptive leading edge subwaveform retracker and further combined with the X-TRACK<br>processing system developed to optimize the accuracy of the sea level time series in coastal<br>oceans. Rates of sea level change are estimated over the period 2002-present along the Jasontracks,<br>from the open ocean to the coast. Different coastal sea level trend behaviors are<br>observed over the study period: constant trends from open ocean to the coast, sometimes<br>decreasing trends, or increasing trends within the last few km to the coast. We compare the<br>computed coastal trends in Southeast Asia with results we previously obtained in other<br>regions (Mediterranean Sea, Western Africa, Northeastern Europe). We further discuss the<br>various small-scale processes able to explain departure of the coastal sea level rate from the<br>offshore (open ocean) rate.</p>

Coastal sea level changes in Africa from retracked Jason altimetry over 2002-2020

2021 ◽  
Author(s):  
Yvan Gouzenes ◽  
Anny Cazenave ◽  
Fabien Léger ◽  
Florence Birol ◽  
Marcello Passaro ◽  
...  
Keyword(s):  
Sea Level ◽  
Leading Edge ◽  
Small Scale ◽  
Coastal Zones ◽  
Sea Level Changes ◽  
Ice Melt ◽  
The World ◽  
Coastal Sea ◽  
Fresh Water Input ◽  
Global Mean

<p>Climate-related sea level changes in the world coastal zones result from the superposition of the global mean rise due to ocean warming and land ice melt, regional changes mostly caused by non-uniform ocean thermal expansion and salinity changes, and small-scale coastal processes (e.g., shelf currents, wind & waves changes, fresh water input from rivers, etc.). So far, satellite altimetry has provided global gridded sea level time series up to 10-15 km to the coast only, preventing estimation of sea level changes very close to the coast. In the context of the ESA Climate Change Initiative coastal sea level project, we have developed a complete reprocessing of high-resolution (20 Hz) Jason-1, 2 and 3 altimetry data along the world coastal zones using the ALES (Adaptative Leading Edge Subwaveform) retracker combined with the XTRACK system dedicated to improve geophysical corrections at the coast. Here we present coastal sea level trends over the period 2002-2020 along the whole African continent. Different coastal sea level trend behaviors are observed over the study period. We compare the computed coastal trends in Africa with results we previously obtained in other regions (Mediterranean Sea, Northeastern Europe, north Indian Sea, southeast Asia and Australia).</p>

The contribution of the East Antarctic Ice Sheet to future sea level rise

2020 ◽  
Author(s):  
Jim Jordan ◽  
Hilmar Gudmundsson ◽  
Adrian Jenkins ◽  
Chris Stokes ◽  
Stewart Jamieson ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Ice Shelf ◽  
Antarctic Ice Sheet ◽  
Mean Sea Level ◽  
Potential Contributor ◽  
Global Mean Sea Level ◽  
Global Mean ◽  
East Antarctic Ice Sheet

<p>The East Antarctic Ice Sheet (EAIS) is the single largest potential contributor to future global mean sea level rise, containing a water mass equivalent of 53 m. Recent work has found the overall mass balance of the EAIS to be approximately in equilibrium, albeit with large uncertainties. However, changes in oceanic conditions have the potential to upset this balance. This could happen by both a general warming of the ocean and also by shifts in oceanic conditions allowing warmer water masses to intrude into ice shelf cavities.</p><p>We use the Úa numerical ice-flow model, combined with ocean-melt rates parameterized by the PICO box mode, to predict the future contribution to global-mean sea level of the EAIS. Results are shown for the next 100 years under a range of emission scenarios and oceanic conditions on a region by region basis, as well as for the whole of the EAIS. </p>

Resolution Dependency of Future Caribbean Sea Level Response

2020 ◽  
Author(s):  
René van Westen ◽  
Henk Dijkstra
Keyword(s):  
High Resolution ◽  
Sea Level Rise ◽  
Sea Level ◽  
Climate Models ◽  
Caribbean Sea ◽  
Model Output ◽  
Low Resolution ◽  
Ocean Eddies ◽  
Resolution Model ◽  
Mesoscale Processes

<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>

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

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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