scholarly journals Feasibility Analysis of GNSS-Reflectometry for Monitoring Coastal Hazards

2021 ◽  
Vol 13 (5) ◽  
pp. 976
Author(s):  
Su-Kyung Kim ◽  
Eunju Lee ◽  
Jihye Park ◽  
Sungwon Shin

Coastal hazards, such as a tsunamis and storm surges, are a critical threat to coastal communities that lead to significant loss of lives and properties. To mitigate their impact, event-driven water level changes should be properly monitored. A tide gauge is one of the conventional water level measurement sensors. Still, alternative measurement systems can be needed to compensate for the role of tide gauge for contingency (e.g., broken and absence, etc.). Global Navigation Satellite System (GNSS) is an emerging water level measurement sensor that processes multipath signals reflected by the water surface that is referred to as GNSS-Reflectometry (GNSS-R). In this study, we adopted the GNSS-R technique to monitor tsunamis and storm surges by analyzing event-driven water level changes. To detect the extreme change of water level, enhanced GNSS-R data processing methods were applied which included the utilization of multi-band GNSS signals, determination of optimal processing window, and Kalman filtering for height rate determination. The impact of coastal hazards on water level retrievals was assessed by computing the confidence level of retrieval (CLR) that was computed based on probability of dominant peak representing the roughness of the water surface. The proposed approach was validated by two tsunami events, induced by 2012 Haida Gwaii earthquake and 2015 Chile earthquake, and two storm surge events, induced by 2017 Hurricane Harvey and occurred in Alaska in 2019. The proposed method successfully retrieved the water levels during the storm surge in both cases with the high correlation coefficients with the nearby tide gauge, 0.944, 0.933, 0.987, and 0.957, respectively. In addition, CLRs of four events are distinctive to the type of coastal events. It is confirmed that the tsunami causes the CLR deduction, while for the storm surges, GNSS-R keep high CLR during the event. These results are possibly used as an indicator of each event in terms of storm surge level and tsunami arrival time. This study shows that the proposed approach of GNSS-R based water level retrieval is feasible to monitor coastal hazards that are tsunamis and storm surges, and it can be a promising tool for investigating the coastal hazards to mitigate their impact and for a better decision making.

2011 ◽  
Vol 94-96 ◽  
pp. 810-814
Author(s):  
Jin Shan Zhang ◽  
Wei Sheng Zhang ◽  
Chen Cheng ◽  
Lin Yun Sun

Bohai Bay is an semi-closed bay, the storm surge disaster is very serious in past. Now more and more large ocean engineering are built here, To study changes of storm surge induced by the construction of large-scale coastal engineering in Bohai Bay in present, 2D numerical storm surge model is established with large - medium - small model nested approach. The three most typical storms surges: 9216, 9711 and by cold wave in October 2003 are simulated in the condition of before and after implementation of planning projects in Bohai Bay. Changes of storm surge water level due to implementation of artificial projects are analysis in this paper.


2019 ◽  
Vol 49 ◽  
pp. 187-196 ◽  
Author(s):  
Anthony James Kettle

Abstract. Storm Tilo on 8–9 November 2007 ranks among the serious winter storms in northern Europe over the past 30 years. Its low pressure centre passed across the northern North Sea, and this led to a cold air outbreak in northwest Europe. Strong north winds across the North Sea contributed to a high storm surge that was serious for coastal regions in eastern England, the Netherlands and Germany. Storm winds and unusually high waves caused shipping accidents and damage to some offshore energy infrastructure. This report presents an outline of the met-ocean conditions and a short overview of storm impacts on societal and energy infrastructure. The progress of the storm surge around the North Sea is analysed using data from the national tide gauge networks. A spectral analysis of the water level data is used to isolate the long period storm surge and short period oscillations (i.e., <4.8 h) from the tidal signal. The calculated skew surge is compared with literature reports for this storm and also with another serious North Sea storm from 31 October–1 November 2006 (Storm Britta). The short period oscillations are compared with the platform and shipping incident reports for the 2 d storm period. The results support previous reports of unusual wave and water level dynamics during some severe regional winter storms.


2000 ◽  
Vol 1 (1) ◽  
pp. 45 ◽  
Author(s):  
G. MUNGOV ◽  
P. DANIEL

The frequency of the storm surges in the Black Sea is lower than that in other regions of the World Ocean but they cause significant damages as the magnitude of the sea level set-up is up to 7-8 times greater than that of other sea level variations. New methods and systems for storm surge forecasting and studying their statistical characteristics are absolutely necessary for the purposes of the coastal zone management. The operational forecasting storm surge model of Meteo-France was adopted for the Black Sea in accordance with the bilateral agreement between Meteo-France and NINMH. The model was verified using tide-gauge observations for the strongest storms observed along the Bulgarian coast over the last 10 years.


2012 ◽  
Vol 1 (33) ◽  
pp. 48
Author(s):  
Christopher Bender ◽  
William Miller ◽  
Ashley Naimaster ◽  
Tucker Mahoney

The South Carolina Surge Study (SCSS) used the tightly coupled SWAN+ADCIRC model to simulate tropical storm surge events. The tightly coupled model allowed calculation of wave-induced water level changes within the storm surge simulations. Inclusion of the wave-induced water level changes represents a more physics-based approach than previous methods that added wave setup after model simulations ended. Development of the SWAN+ADCIRC model included validation of water levels to local tidal forcing and for three historical hurricanes — Hazel (1954), Hugo (1989), and Ophelia (2005). The validation for waves did not include Hurricane Hazel because measured data was unavailable. Additional comparisons with WAM model results provided supplemental support to the SWAN model results. Model output applied in comparisons included contour plots of maximum wave parameters, time series of wave parameters at selected locations, and wave spectra.


Author(s):  
Andrei Raphael Dita ◽  
Eric Cruz ◽  
Jose Carlo Eric Santos

A marina for small crafts is being planned to be built within Caliraya Lake situated at an elevation of 290m above Mean Sea Level (maMSL). Unlike sea-connected water bodies, the water level of Caliraya Lake is largely influenced not by tidal fluctuations, but by the operational water level requirements of the hydroelectric power plant that it caters to. Due to the large difference in the Normal High Water Level (NHWL) and Minimum Operating Level (MOL) of the lake of 2.5m, a floating pontoon marina with guide piles was contemplated to be used. The marina analysis and design approaches implemented in this study considered waves generated by prevailing winds and ship-generated wakes to assess the wave climate and tranquility within the marina. Since the project area is also frequently tracked by typhoons, wind- and pressure-driven storm surges were also used for the vertical siting of the guide piles. Lastly, based on the geographic appearances of the lake shoreline and with the small size of the lake, the fetch limitations resulted to very small wind-generated waves and wind setup considered as wind-driven storm surge components. In comparison to open seas where wind-driven storm surge accounts for approximately 95percent of the total storm surge, the wind-driven storm surge components for the potentially critical historical typhoons which traversed within 200-km radius of the project area only generated 10-30percent of the total storm surge considered for the vertical siting.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/m-XEEw6r99g


2020 ◽  
Author(s):  
Nary La ◽  
Byoung Woong An ◽  
KiRyong Kang ◽  
Sang Myeong Oh ◽  
YoonJae Kim

&lt;p&gt;&lt;span&gt;In recent years, coastal disasters have been frequently caused by typhoons and storm surges accompanied by high waves due to global warming and the changing marine environment. In addition, the development of coastal areas in Korea has also led to suffering great damage to society every year.&amp;#160;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;To cope with this issue, we have developed a new storm-surge prediction system based on the NEMO model for improving the predictability both the tide and the surge. This new regional tide-surge prediction system (RTSM) is constructed with a two-dimensional barotropic sigma coordinates and has a 1/12 degrees horizontal resolution. To find optimal coefficients of this model, several sensitivity experiments were conducted and verified with tide gauge measurements from the KHOA (Korea Hydrographic and Oceanographic Agency). Finally, we selected a bathymetry from SRTM (Shuttle Radar Topography Mission), Charnock coefficient as a constant value of 0.275 and the reference pressure for the inverse barometric effect as the domain mean. As the result of comparing surge-height predictions with the currently operating model (OPER-RTSM), the new system (RTSM) showed roughly 30% higher in forecast accuracy than the previous OPER-RTSM.&lt;/span&gt;&lt;/p&gt;


1978 ◽  
Vol 1 (16) ◽  
pp. 58
Author(s):  
P.F. Hamblin

Storm surges in enclosed seas although generally not as large in amplitude as their oceanic counterparts are nonetheless of considerable importance when low lying shoreline profiles, shallow water depth, and favourable geographical orientation to storm winds occur together. High water may result in shoreline innundation and in enhanced shoreline erosion. Conversely low water levels are hazardous to navigation. The purpose of this paper is to discuss the problem of storm surge forecasting in enclosed basins with emphasis on automated operational procedures. In general, operational forecasting methods must be based on standard forecast parameters, require a minimum of computational effort in the preparation of the forecast, must be applicable to lakes of different geometry and to any point on the shore, and to be able to resolve water level changes on an hourly basis to 10 cm in the case of high water level excursions associated with large lakes and less than that for smaller lakes. Particular physical effects arising in lakes which make these constraints difficult to fulfill are the reflections of resurgences of water levels arising from lateral boundaries, the stability of the atmospheric boundary layer and the presence of such subsynoptic disturbances as squall lines and travelling pressure jumps.


Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1559
Author(s):  
Halina Kowalewska-Kalkowska

The Odra River mouth area is a region of the Southern Baltic coastal zone especially prone to the influence of storm surges. In the present study, the height and extent of the Baltic storm surges, and temporal offsets of the respective maximum water level occurrences in the Odra River mouth area were explored using cross-correlation, cluster analysis and principal component analysis. The analyses were based on hourly water level readings retrieved from water gauging stations located along the lower Odra reaches and at the coasts of the Szczecin Lagoon and the Pomeranian Bay during storm surge years 2008/2009–2019/2020. The analysis of mutual relationships between water levels during storm surges indicated that the extent of marine influence on the lower Odra River and within the Szczecin Lagoon was variable during the studied surge events, and dependent on meteorological conditions (the strongest during the sustained occurrence of wind blowing from the northern sector), discharge from the Odra River catchment (the strongest at low discharge), ice conditions on the lower Odra (suppressing the storm surge propagation upstream), and general sea level in the Pomeranian Bay (stronger at high sea levels). The strongest correlation between sea levels at Świnoujście and water levels in the Szczecin Lagoon and the lower Odra was found at a 6–7 h offset. The extent of storm surges usually reached 100 km up the lower Odra channels, less frequently reaching 130 km away from the sea.


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