scholarly journals Effect of Bottom Friction, Wind Drag Coefficient, and Meteorological Forcing in Hindcast of Hurricane Rita Storm Surge Using SWAN + ADCIRC Model

2017 ◽  
Vol 5 (3) ◽  
pp. 38 ◽  
Author(s):  
Muhammad Akbar ◽  
Simbarashe Kanjanda ◽  
Abram Musinguzi
Keyword(s):  
Drag Coefficient ◽  
Storm Surge ◽  
Bottom Friction ◽  
Meteorological Forcing ◽  
Hurricane Rita ◽  
Adcirc Model

scholarly journals Understanding Hurricane Storm Surge Generation and Propagation Using a Forecasting Model, Forecast Advisories and Best Track in a Wind Model, and Observed Data—Case Study Hurricane Rita

2019 ◽  
Vol 7 (3) ◽  
pp. 77 ◽  
Author(s):  
Abram Musinguzi ◽  
Muhammad K. Akbar ◽  
Jason G. Fleming ◽  
Samuel K. Hargrove
Keyword(s):  
Storm Surge ◽  
Surface Wind ◽  
Storm Surges ◽  
Wind Pressure ◽  
Forecasting Model ◽  
Wind Fields ◽  
Wind Model ◽  
Meteorological Forcing ◽  
Hurricane Rita

Meteorological forcing is the primary driving force and primary source of errors for storm surge forecasting. The objective of this study was to learn how forecasted meteorological forcing influences storm surge generation and propagation during a hurricane so that storm surge models can be reliably used to forecast actual events. Hindcasts and forecasts of Hurricane Rita (2005) storm surge was used as a case study. Meteorological forcing or surface wind/pressure fields for Hurricane Rita were generated using both the Weather Research and Forecasting (WRF) full-scale forecasting model along with archived hurricane advisories ingested into a sophisticated parametric wind model, namely Generalized Asymmetric Holland Model (GAHM). These wind fields were used to forecast Rita storm surges. Observation based wind fields from the OceanWeather Inc. (OWI) Interactive Objective Kinematic Analysis (IOKA) model, and Best track wind data ingested into the GAHM model were used to generate wind fields for comparison purposes. These wind fields were all used to hindcast Rita storm surges with the ADvanced CIRCulation (ADCIRC) model coupled with the Simulating Waves Nearshore (SWAN) model in a tightly coupled storm surge-wave model referred to as ADCIRC+SWAN. The surge results were compared against a quality-controlled database of observed data to assess the performance of these wind fields on storm surge generation and propagation. The surge hindcast produced by the OWI wind field performed the best, although some high water mark (HWM) locations were overpredicted. Although somewhat underpredicted, the WRF wind fields forecasted wider surge extent and wetted most HWM locations. The hindcast using the Best track parameters in the GAHM and the forecast using forecast/advisories from the National Hurricane Center (NHC) in the GAHM produced strong and narrow wind fields causing localized high surges, which resulted in overprediction near landfall while many HWM locations away from wind bands remained dry.

scholarly journals Measuring compound flood potential from river discharge and storm surge extremes at the global scale

2020 ◽  
Vol 20 (2) ◽  
pp. 489-504 ◽  
Author(s):  
Anaïs Couasnon ◽  
Dirk Eilander ◽  
Sanne Muis ◽  
Ted I. E. Veldkamp ◽  
Ivan D. Haigh ◽  
...  
Keyword(s):  
Storm Surge ◽  
River Discharge ◽  
Flood Hazard ◽  
Joint Probability ◽  
Global Scale ◽  
Statistical Dependence ◽  
Dependence Structure ◽  
Meteorological Forcing ◽  
Continental Scale ◽  
Bivariate Dependence

Abstract. The interaction between physical drivers from oceanographic, hydrological, and meteorological processes in coastal areas can result in compound flooding. Compound flood events, like Cyclone Idai and Hurricane Harvey, have revealed the devastating consequences of the co-occurrence of coastal and river floods. A number of studies have recently investigated the likelihood of compound flooding at the continental scale based on simulated variables of flood drivers, such as storm surge, precipitation, and river discharges. At the global scale, this has only been performed based on observations, thereby excluding a large extent of the global coastline. The purpose of this study is to fill this gap and identify regions with a high compound flooding potential from river discharge and storm surge extremes in river mouths globally. To do so, we use daily time series of river discharge and storm surge from state-of-the-art global models driven with consistent meteorological forcing from reanalysis datasets. We measure the compound flood potential by analysing both variables with respect to their timing, joint statistical dependence, and joint return period. Our analysis indicates many regions that deviate from statistical independence and could not be identified in previous global studies based on observations alone, such as Madagascar, northern Morocco, Vietnam, and Taiwan. We report possible causal mechanisms for the observed spatial patterns based on existing literature. Finally, we provide preliminary insights on the implications of the bivariate dependence behaviour on the flood hazard characterisation using Madagascar as a case study. Our global and local analyses show that the dependence structure between flood drivers can be complex and can significantly impact the joint probability of discharge and storm surge extremes. These emphasise the need to refine global flood risk assessments and emergency planning to account for these potential interactions.

scholarly journals Adjusting the Wind Stress Drag Coefficient in Storm Surge Forecasting Using an Adjoint Technique

2013 ◽  
Vol 30 (3) ◽  
pp. 590-608 ◽  
Author(s):  
Shiqiu Peng ◽  
Yineng Li ◽  
Lian Xie
Keyword(s):  
Data Assimilation ◽  
Drag Coefficient ◽  
Storm Surge ◽  
Wind Stress ◽  
Weather Prediction ◽  
Ocean Model ◽  
Error Sources ◽  
Empirical Parameter ◽  
Forecasting Errors ◽  
Storm Surge Forecasting

Abstract A three-dimensional ocean model and its adjoint model are used to adjust the drag coefficient in the calculation of wind stress for storm surge forecasting. A number of identical twin experiments (ITEs) with different error sources imposed are designed and performed. The results indicate that when the errors come from the wind speed, the drag coefficient is adjusted to an “optimal value” to compensate for the wind errors, resulting in significant improvements of the specific storm surge forecasting. In practice, the “true” drag coefficient is unknown and the wind field, which is usually calculated by an empirical parameter model or a numerical weather prediction model, may contain large errors. In addition, forecasting errors may also come from imperfect model physics and numerics, such as insufficient resolution and inaccurate physical parameterizations. The results demonstrate that storm surge forecasting errors can be reduced through data assimilation by adjusting the drag coefficient regardless of the error sources. Therefore, although data assimilation may not fix model imperfection, it is effective in improving storm surge forecasting by adjusting the wind stress drag coefficient using the adjoint technique.

scholarly journals Measuring compound flood potential from river discharge and storm surge extremes at the global scale and its implications for flood hazard

2019 ◽  
Author(s):  
Anaïs Couasnon ◽  
Dirk Eilander ◽  
Sanne Muis ◽  
Ted I. E. Veldkamp ◽  
Ivan D. Haigh ◽  
...  
Keyword(s):  
Storm Surge ◽  
River Discharge ◽  
Flood Hazard ◽  
Joint Probability ◽  
Global Scale ◽  
Statistical Dependence ◽  
Dependence Structure ◽  
Meteorological Forcing ◽  
Continental Scale ◽  
Bivariate Dependence

Abstract. The interaction between physical drivers from oceanographic, hydrological, and meteorological processes in coastal areas can result in compound flooding. Compound flood events, like Cyclone Idai and Hurricane Harvey, have revealed the devastating consequences of the co-occurrence of coastal and river floods. A number of studies have recently investigated the likelihood of compound flooding at the continental scale based on simulated variables of flood drivers such as storm surge, precipitation, and river discharges. At the global scale, this has only been performed based on observations, thereby excluding a large extent of the global coastline. The purpose of this study is to fill this gap and identify potential hotspots of compound flooding from river discharge and storm surge extremes in river mouths globally. To do so, we use daily time-series of river discharge and storm surge from state-of-the-art global models driven with consistent meteorological forcing from reanalysis datasets. We measure the compound flood potential by analysing both variables with respect to their timing, joint statistical dependence, and joint return period. We find many hotspot regions of compound flooding that could not be identified in previous global studies based on observations alone, such as: Madagascar, Northern Morocco, Vietnam, and Taiwan. We report possible causal mechanisms for the observed spatial patterns based on existing literature. Finally, we provide preliminary insights on the implications of the bivariate dependence behaviour on the flood hazard characterisation using Madagascar as a case study. Our global and local analyses show that the dependence structure between flood drivers can be complex and can significantly impact the joint probability of discharge and storm surge extremes. These emphasise the need to refine global flood risk assessments and emergency planning to account for these potential interactions.

scholarly journals “Certain Death” from Storm Surge: A Comparative Study of Household Responses to Warnings about Hurricanes Rita and Ike

2014 ◽  
Vol 6 (4) ◽  
pp. 425-433 ◽  
Author(s):  
Hung-Lung Wei ◽  
Michael K. Lindell ◽  
Carla S. Prater
Keyword(s):  
Storm Surge ◽  
Similar Data ◽  
Jefferson County ◽  
Questionnaire Data ◽  
Hurricane Ike ◽  
Hurricane Rita ◽  
Warning Message ◽  
Show Evidence ◽  
Initial Source ◽  
Household Responses

Abstract This study examines the effect of an unusual “certain death” warning message on Galveston, Harris, and Jefferson County, Texas, residents’ expectations of storm surge damage and evacuation decisions during Hurricane Ike. The effect of this message was tested by comparing questionnaire data collected after Hurricane Ike to similar data collected 3 yr earlier after Hurricane Rita. If the certain death message had an effect, one would expect nonsignificant differences in perceptions of the two storms’ surge threats because the category 2 storm (Ike) had a surge that was more characteristic of a category 5 storm (Rita). However, the ratings of the storm surge threat for Ike were significantly lower than those for Rita in Galveston County—the point of landfall. Moreover, evacuation rates for Ike were consistently lower than those for Rita in all three counties, and there were no statistically significant differences between storms in the correlations of expected storm surge damage with evacuation decisions. In summary, these data fail to show evidence that the dramatic certain death warning increased expectations of surge threat and evacuation decisions. These findings underscore the need for those disseminating weather warnings to better understand how hurricane warnings flow from an initial source through intermediate links to the ultimate receivers as well as how these ultimate receivers receive, heed, interpret, and decide how to act upon those warnings.

scholarly journals Morphological responses of the Wax Lake Delta, Louisiana, to Hurricanes Rita

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Fei Xing ◽  
James P.M. Syvitski ◽  
Albert J. Kettner ◽  
Ehab A. Meselhe ◽  
John H. Atkinson ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Storm Surge ◽  
Water Depth ◽  
Extreme Weather Events ◽  
Shear Stresses ◽  
Hurricane Rita ◽  
Hurricane Track ◽  
Wax Lake Delta ◽  
The Right ◽  
The Impact

This study examines the morphodynamic response of a deltaic system to extreme weather events. The Wax Lake Delta (WLD) in Louisiana, USA, is used to illustrate the impact of extreme events (hurricanes) on a river-dominated deltaic system. Simulations using the open source Delft3D model reveal that Hurricane Rita, which made landfall 120 km to the west of WLD as a Category 3 storm in 2005, caused erosion on the right side and deposition on the left side of the hurricane eye track on the continental shelf line (water depth 10 m to 50 m). Erosion over a wide area occurred both on the continental shelf line and in coastal areas when the hurricane moved onshore, while deposition occurred along the Gulf coastline (water depth < 5 m) when storm surge water moved back offshore. The numerical model estimated that Hurricane Rita’s storm surge reached 2.5 m, with maximum currents of 2.0 m s–1, and wave heights of 1.4 m on the WLD. The northwestern-directed flow and waves induced shear stresses, caused erosion on the eastern banks of the deltaic islands and deposition in channels located west of these islands. In total, Hurricane Rita eroded more than 500,000 m3 of sediments on the WLD area. Including waves in the analysis resulted in doubling the amount of erosion in the study area, comparing to the wave-excluding scenario. The exclusion of fluvial input caused minor changes in deltaic morphology during the event. Vegetation cover was represented as rigid rods in the model which add extra source terms for drag and turbulence to influence the momentum and turbulence equations. Vegetation slowed down the floodwater propagation and decreased flow velocity on the islands, leading to a 47% reduction in the total amount of erosion. Morphodynamic impact of the hurricane track relative to the delta was explored. Simulations indicate that the original track of Hurricane Rita (landfall 120 km west of the WLD) produced twice as much erosion and deposition at the delta compared to a hurricane of a similar intensity that made landfall directly on the delta. This demonstrates that the wetlands located on the right side of a hurricane track experience more significant morphological changes than areas located directly on the hurricane track.

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