NUMERICAL MODELING OF STORM SURGES, WIND WAVES AND FLOODING IN THE TAGANROG BAY

2017 ◽  
Author(s):  
Vladimir Fomin ◽  
Vladimir Fomin ◽  
Dmitrii Alekseev ◽  
Dmitrii Alekseev ◽  
Dmitrii Lazorenko ◽  
...  
Keyword(s):  
Sea Level ◽  
Wind Waves ◽  
Storm Surges ◽  
Atmospheric Model ◽  
Extreme Storm ◽  
Regional Atmospheric Model ◽  
Sea Level Oscillations ◽  
Flooding And Drying ◽  
Flooded Area ◽  
Taganrog Bay

Storm surges and wind waves are ones of the most important hydrological characteristics, which determine dynamics of the Sea of Azov. Extreme storm surges in Taganrog Bay and flooding in the Don Delta can be formed under the effect of strong western winds. In this work the sea level oscillations and wind waves in the Taganrog Bay were simulated by means of the coupled SWAN+ADCIRC numerical model, taking into account the flooding and drying mechanisms. The calculations were carried out on an unstructured mesh with high resolution. The wind and atmospheric pressure fields for the extreme storm from 20 to 28 of September, 2014 obtained from WRF regional atmospheric model were used as forcing. The analysis of simulation results showed the following. The western and northern parts of the Don Delta were the most flood-prone during the storm. The size of the flooded area of the Don Delta exceeded 50%. Interaction of storm surge and wind wave accelerated the flooding process, increased the size of the flooded area and led to the intensification of wind waves in the upper of Taganrog Bay due to the general rise of the sea level.

NUMERICAL MODELING OF STORM SURGES, WIND WAVES AND FLOODING IN THE TAGANROG BAY

2017 ◽  
Author(s):  
Vladimir Fomin ◽  
Vladimir Fomin ◽  
Dmitrii Alekseev ◽  
Dmitrii Alekseev ◽  
Dmitrii Lazorenko ◽  
...  
Keyword(s):  
Sea Level ◽  
Wind Waves ◽  
Storm Surges ◽  
Atmospheric Model ◽  
Extreme Storm ◽  
Regional Atmospheric Model ◽  
Sea Level Oscillations ◽  
Flooding And Drying ◽  
Flooded Area ◽  
Taganrog Bay

Storm surges and wind waves are ones of the most important hydrological characteristics, which determine dynamics of the Sea of Azov. Extreme storm surges in Taganrog Bay and flooding in the Don Delta can be formed under the effect of strong western winds. In this work the sea level oscillations and wind waves in the Taganrog Bay were simulated by means of the coupled SWAN+ADCIRC numerical model, taking into account the flooding and drying mechanisms. The calculations were carried out on an unstructured mesh with high resolution. The wind and atmospheric pressure fields for the extreme storm from 20 to 28 of September, 2014 obtained from WRF regional atmospheric model were used as forcing. The analysis of simulation results showed the following. The western and northern parts of the Don Delta were the most flood-prone during the storm. The size of the flooded area of the Don Delta exceeded 50%. Interaction of storm surge and wind wave accelerated the flooding process, increased the size of the flooded area and led to the intensification of wind waves in the upper of Taganrog Bay due to the general rise of the sea level.

scholarly journals “Grey swan” storm surges pose a greater coastal flood hazard than climate change

2021 ◽  
Author(s):  
Kevin Horsburgh ◽  
Ivan D. Haigh ◽  
Jane Williams ◽  
Michela De Dominicis ◽  
Judith Wolf ◽  
...  
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Storm Surges ◽  
Natural Variability ◽  
Major Incident ◽  
Dynamical Response ◽  
Mean Sea Level ◽  
Coastal Flood ◽  
Extreme Storm ◽  
Observational Record

AbstractIn this paper, we show that over the next few decades, the natural variability of mid-latitude storm systems is likely to be a more important driver of coastal extreme sea levels than either mean sea level rise or climatically induced changes to storminess. Due to their episodic nature, the variability of local sea level response, and our short observational record, understanding the natural variability of storm surges is at least as important as understanding projected long-term mean sea level changes due to global warming. Using the December 2013 North Atlantic Storm Xaver as a baseline, we used a meteorological forecast modification tool to create “grey swan” events, whilst maintaining key physical properties of the storm system. Here we define “grey swan” to mean an event which is expected on the grounds of natural variability but is not within the observational record. For each of these synthesised storm events, we simulated storm tides and waves in the North Sea using hydrodynamic models that are routinely used in operational forecasting systems. The grey swan storms produced storm surges that were consistently higher than those experienced during the December 2013 event at all analysed tide gauge locations along the UK east coast. The additional storm surge elevations obtained in our simulations are comparable to high-end projected mean sea level rises for the year 2100 for the European coastline. Our results indicate strongly that mid-latitude storms, capable of generating more extreme storm surges and waves than ever observed, are likely due to natural variability. We confirmed previous observations that more extreme storm surges in semi-enclosed basins can be caused by slowing down the speed of movement of the storm, and we provide a novel explanation in terms of slower storm propagation allowing the dynamical response to approach equilibrium. We did not find any significant changes to maximum wave heights at the coast, with changes largely confined to deeper water. Many other regions of the world experience storm surges driven by mid-latitude weather systems. Our approach could therefore be adopted more widely to identify physically plausible, low probability, potentially catastrophic coastal flood events and to assist with major incident planning.

Analysis of the eastern Adriatic sea-level extremes

2021 ◽  
Author(s):  
Marija Pervan ◽  
Jadranka Šepić
Keyword(s):  
Sea Level ◽  
Adriatic Sea ◽  
Hot Spot ◽  
Storm Surges ◽  
Low Pressure ◽  
Long Period ◽  
Short Period ◽  
Sea Level Oscillations ◽  
Low Pass ◽  
Level Height

<p>The Adriatic Sea is known to be under a high flooding risk due to both storm surges and meteorological tsunamis, with the latter defined as short-period sea-level oscillations alike to tsunamis but generated by atmospheric processes. In June 2017, a tide-gauge station with a 1-min sampling resolution has been installed at Stari Grad (middle Adriatic Sea), the well-known meteotsunami hot-spot, which is, also, often hit by storm surges. </p><p>Three years of corresponding sea-level measurements were analyzed, and 10 strongest episodes of each of the following extreme types were extracted from the residual series: (1) positive long-period (T > 210 min) extremes; (2) negative long-period (T > 210 min) extremes; (3) short-period (T < 210) extremes. Long-period extremes were defined as situations during which sea level surpasses (is lower than) 99.7 (i.e. 2) percentile of sea level height, and short-period extremes as situations during which variance of short-period sea-level oscillations is higher than 99.4 percentile of total variance[J1]  of short-period series. A strong seasonal signal was detected for all extremes, with most of the positive long-period extremes appearing during November to February, and most of the negative long-period extremes during January to February. As for the short-period extremes, these appear evenly throughout the year, but strongest events seem to appear during May to July.</p><p>All events were associated to characteristic atmospheric situations, using both local measurements of the atmospheric variables, and ERA5 Reanalysis dataset. It was shown that positive low-pass extremes commonly appear during presence of low pressure over the Adriatic associated with strong SE winds (“sirocco”), and negative low-pass extremes are associated to the high atmospheric pressure over the area associated with either strong NE winds (“bora”), or no winds at all. On the other hand, high-pass sea level extremes are noticed during two distinct types of atmospheric situations corresponding to both “bad” (low pressure, strong SE wind) and “nice” (high pressure, no wind) weather.</p><p>It is particularly interesting that short-period extremes, of which strongest are meteotsunamis, are occasionally coincident with positive long-period extremes contributing with up to 50 percent to total sea level height – thus implying existence of a double danger phenomena (meteotsunami + storm surge). </p>

scholarly journals Assessment of the Greenland ice sheet–atmosphere feedbacks for the next century with a regional atmospheric model coupled to an ice sheet model

2019 ◽  
Vol 13 (1) ◽  
pp. 373-395 ◽  
Author(s):  
Sébastien Le clec'h ◽  
Sylvie Charbit ◽  
Aurélien Quiquet ◽  
Xavier Fettweis ◽  
Christophe Dumas ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Atmospheric Model ◽  
Ice Dynamics ◽  
Surface Slopes ◽  
Regional Atmospheric Model ◽  
Basin Scale ◽  
Coupling Strategies

Abstract. In the context of global warming, growing attention is paid to the evolution of the Greenland ice sheet (GrIS) and its contribution to sea-level rise at the centennial timescale. Atmosphere–GrIS interactions, such as the temperature–elevation and the albedo feedbacks, have the potential to modify the surface energy balance and thus to impact the GrIS surface mass balance (SMB). In turn, changes in the geometrical features of the ice sheet may alter both the climate and the ice dynamics governing the ice sheet evolution. However, changes in ice sheet geometry are generally not explicitly accounted for when simulating atmospheric changes over the Greenland ice sheet in the future. To account for ice sheet–climate interactions, we developed the first two-way synchronously coupled model between a regional atmospheric model (MAR) and a 3-D ice sheet model (GRISLI). Using this novel model, we simulate the ice sheet evolution from 2000 to 2150 under a prolonged representative concentration pathway scenario, RCP8.5. Changes in surface elevation and ice sheet extent simulated by GRISLI have a direct impact on the climate simulated by MAR. They are fed to MAR from 2020 onwards, i.e. when changes in SMB produce significant topography changes in GRISLI. We further assess the importance of the atmosphere–ice sheet feedbacks through the comparison of the two-way coupled experiment with two other simulations based on simpler coupling strategies: (i) a one-way coupling with no consideration of any change in ice sheet geometry; (ii) an alternative one-way coupling in which the elevation change feedbacks are parameterized in the ice sheet model (from 2020 onwards) without taking into account the changes in ice sheet topography in the atmospheric model. The two-way coupled experiment simulates an important increase in surface melt below 2000 m of elevation, resulting in an important SMB reduction in 2150 and a shift of the equilibrium line towards elevations as high as 2500 m, despite a slight increase in SMB over the central plateau due to enhanced snowfall. In relation with these SMB changes, modifications of ice sheet geometry favour ice flux convergence towards the margins, with an increase in ice velocities in the GrIS interior due to increased surface slopes and a decrease in ice velocities at the margins due to decreasing ice thickness. This convergence counteracts the SMB signal in these areas. In the two-way coupling, the SMB is also influenced by changes in fine-scale atmospheric dynamical processes, such as the increase in katabatic winds from central to marginal regions induced by increased surface slopes. Altogether, the GrIS contribution to sea-level rise, inferred from variations in ice volume above floatation, is equal to 20.4 cm in 2150. The comparison between the coupled and the two uncoupled experiments suggests that the effect of the different feedbacks is amplified over time with the most important feedbacks being the SMB–elevation feedbacks. As a result, the experiment with parameterized SMB–elevation feedback provides a sea-level contribution from GrIS in 2150 only 2.5 % lower than the two-way coupled experiment, while the experiment with no feedback is 9.3 % lower. The change in the ablation area in the two-way coupled experiment is much larger than those provided by the two simplest methods, with an underestimation of 11.7 % (14 %) with parameterized feedbacks (no feedback). In addition, we quantify that computing the GrIS contribution to sea-level rise from SMB changes only over a fixed ice sheet mask leads to an overestimation of ice loss of at least 6 % compared to the use of a time variable ice sheet mask. Finally, our results suggest that ice-loss estimations diverge when using the different coupling strategies, with differences from the two-way method becoming significant at the end of the 21st century. In particular, even if averaged over the whole GrIS the climatic and ice sheet fields are relatively similar; at the local and regional scale there are important differences, highlighting the importance of correctly representing the interactions when interested in basin scale changes.

scholarly journals Coastal flooding: impact of waves on storm surge during extremes – a case study for the German Bight

2016 ◽  
Vol 16 (11) ◽  
pp. 2373-2389 ◽  
Author(s):  
Joanna Staneva ◽  
Kathrin Wahle ◽  
Wolfgang Koch ◽  
Arno Behrens ◽  
Luciana Fenoglio-Marc ◽  
...  
Keyword(s):  
Sea Level ◽  
German Bight ◽  
Wind Waves ◽  
Three Dimensional ◽  
Coupled Model ◽  
Circulation Model ◽  
Coastal Flooding ◽  
Storm Events ◽  
Extreme Storm ◽  
Wave Induced

Abstract. This study addresses the impact of wind, waves, tidal forcing and baroclinicity on the sea level of the German Bight during extreme storm events. The role of wave-induced processes, tides and baroclinicity is quantified, and the results are compared with in situ measurements and satellite data. A coupled high-resolution modelling system is used to simulate wind waves, the water level and the three-dimensional hydrodynamics. The models used are the wave model WAM and the circulation model GETM. The two-way coupling is performed via the OASIS3-MCT coupler. The effects of wind waves on sea level variability are studied, accounting for wave-dependent stress, wave-breaking parameterization and wave-induced effects on vertical mixing. The analyses of the coupled model results reveal a closer match with observations than for the stand-alone circulation model, especially during the extreme storm Xaver in December 2013. The predicted surge of the coupled model is significantly enhanced during extreme storm events when considering wave–current interaction processes. This wave-dependent approach yields a contribution of more than 30 % in some coastal areas during extreme storm events. The contribution of a fully three-dimensional model compared with a two-dimensional barotropic model showed up to 20 % differences in the water level of the coastal areas of the German Bight during Xaver. The improved skill resulting from the new developments justifies further use of the coupled-wave and three-dimensional circulation models in coastal flooding predictions.

Impacts of mean sea-level rise and marine extremes on islands

2020 ◽  
Author(s):  
Marta Marcos ◽  
Angel Amores
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Wind Waves ◽  
Storm Surges ◽  
Sandy Beaches ◽  
Local Economy ◽  
Mean Sea Level ◽  
Coastal Impacts ◽  
Extreme Hazards ◽  
And Migration

<p>For how long low-elevation coastal areas will be habitable under the effects of mean sea-level rise and marine extreme hazards? Mean sea-level rise, despite having a global origin, has severe local coastal impacts, as it raises the baseline level on top of which extreme storm surges and wind-waves reach the coastlines and, consequently, increases coastal exposure. In this presentation we will show coastal modelling exercises, fed with regionalised climate information of mean sea level and marine extremes, and applied in different environments that include sandy beaches and atoll islands. The outputs are aimed at anticipating the potential impacts of the dominant drivers in terms of land loss, coastal flooding and erosion. Our examples will be focusing on islands, for which the effects of increased coastal exposure are relatively larger, where local economy is often linked to coastal activities and retreat and migration are hampered by the limited land availability.</p>

scholarly journals PREDICTING EXTREME WATER LEVELS AROUND AUSTRALIA

2020 ◽  
pp. 7
Author(s):  
Charitha Pattiaratchi ◽  
Yasha Hetzel ◽  
Ivica Janekovic
Keyword(s):  
Sea Level ◽  
Land Use Planning ◽  
Wind Waves ◽  
Storm Surges ◽  
Flood Management ◽  
Water Levels ◽  
Coastal Development ◽  
Sea Levels ◽  
Extreme Water Levels ◽  
Rising Sea Levels

Throughout history, coastal settlers have had to adapt to periodic coastal flooding. However, as a society we have become increasingly vulnerable to extreme water level events as our cities and our patterns of coastal development become more intricate, populated and interdependent. In addition to this, there is now a real and growing concern about rising sea levels. Accurate estimates of extreme water levels are therefore critical for coastal planning and emergency planning and response. The occurrence of extreme water levels along low-lying, highly populated and/or developed coastlines can lead to considerable loss of life and billions of dollars of damage to coastal infrastructure. Therefore, it is vitally important that the exceedance probabilities of extreme water levels be accurately evaluated to inform risk-based flood management, engineering and future land-use planning. This objectives of this study was to estimate present day extreme sea level exceedance probabilities due to combination of storm surges, tides and mean sea level (including wind-waves) around the coastline of Australia.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/vGaB85VRujs

On the effect of sea level increases during the Storm Gloria

2021 ◽  
Author(s):  
Begoña Pérez Gómez
Keyword(s):  
Sea Level ◽  
Atmospheric Pressure ◽  
Tide Gauge ◽  
Wind Waves ◽  
Storm Surges ◽  
Western Mediterranean ◽  
Economic Activities ◽  
Resonance Effects ◽  
Spatial And Temporal Scales ◽  
In Situ Data

<p>The final extent of coastal impacts during extreme events depends on a complex combination of factors (coastal morphology, infrastructures, population, economic activities), and meteorological and oceanographic variables interacting at different spatial and temporal scales (e.g.: precipitation, atmospheric pressure, wind, waves, currents and sea level). Coastal sea level is a key driver of most of these impacts, starting by the increased vulnerability of worldwide coastlines due to mean sea level rise. In January 2020, the storm Gloria hit the Western Mediterranean Sea causing severe coastal damages, destruction of infrastructures, flooding and several casualties. The dynamic evolution of sea level during this storm is presented, demonstrating its contribution to the mentioned impacts at different timescales: long-term sea level and seasonal changes, tides and storm surges, and higher frequency oscillations of the order of minutes, associated with different forcing agents like wind-waves, wind and atmospheric pressure variations or edge waves. Tide gauge data are used as the main source of information including the detection and characterization of record-breaking high-frequency oscillations, (infragravity waves, meteotsunamis, resonance effects), thanks to a new software that operationally characterizes these processes from 2Hz raw data. The storm surge component, that also beat the record along Valencia coastline, is analyzed with in-situ data and model outputs from different operational forecasting systems in the region. The exercise shows the difficulty of disentangling different wave, wind and atmospheric pressure contributions to sea level increase during a storm.  </p>

Intraannual and interannual variability of storm surges in the North Caspian Sea

2020 ◽  
Vol 3 ◽  
pp. 42-57
Author(s):  
A.V. Pavlova ◽  
◽  
V.S. Arkhipkin ◽  
S.A. Myslenkov ◽  
◽  
...  
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Storm Surges ◽  
Western Coast ◽  
Coastal Zones ◽  
The Caspian Sea ◽  
Sea Level Fluctuations ◽  
The North ◽  
Inundation Area ◽  
Flooded Area

The article presents the results of hydrodynamic modeling of sea level fluctuations in the Caspian Sea using the ADCIRC model for the period from 1979 to 2017. Surges are simulated using an irregular triangulation computational grid with a changing cell size, that easily adapts to changes in shoreline and depth and, therefore, more accurately describes coastal zones. It is found that the seasonal variability of surges is characterized by a maximum in winter and spring and by a minimum in summer. On the western coast of the North Caspian Sea, the maximum sea-level fluctuations are observed in December-February, and on the northern and eastern coasts – in February and March. The areas of inundation of the coastal territory of the Russian sector of the sea are identified. For the surge on March 12–16, 1995, that was one of the most catastrophic ones in terms of its consequences, the inundation area made up 53% of the possible flooded area, and the inundation area for the surge registered on March 27–April 1, 2015 made up 71 %. The more severe consequences of the surge in 1995 are associated with the fact that the mean annual sea level, that determines the possible flooded area, in 1995 was much higher than in 2015. Keywords: ADCIRC, Caspian Sea, unstructured grid, storm surge, sea level, numerical modeling Fig. 11. Ref. 15.

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