Cos Cob, CT, United States
Cos Cob, CT, United States

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Dietrich J.C.,University of Notre Dame | Bunya S.,University of Notre Dame | Bunya S.,Arcadis | Westerink J.J.,University of Notre Dame | And 12 more authors.
Monthly Weather Review | Year: 2010

Hurricanes Katrina and Rita were powerful storms that impacted southern Louisiana and Mississippi during the 2005 hurricane season. In Part I, the authors describe and validate a high-resolution coupled riverine flow, tide, wind, wave, and storm surge model for this region. Herein, the model is used to examine the evolution of these hurricanes in more detail. Synoptic histories show how storm tracks, winds, and waves interacted with the topography, the protruding Mississippi River delta, east-west shorelines, manmade structures, and low-lying marshes to develop and propagate storm surge. Perturbations of the model, in which the waves are not included, show the proportional importance of the wave radiation stress gradient induced setup. © 2010 American Meteorological Society.

Wang X.L.,Environment Canada | Feng Y.,Environment Canada | Swail V.R.,Environment Canada | Cox A.,Oceanweather Inc.
Journal of Climate | Year: 2015

This study characterizes historical changes in surface wind speed and ocean surface waves in the Beaufort- Chukchi-Bering Seas using Environment Canada's Beaufort Wind and Wave Reanalysis for the period 1970-2013. The results show that both the significant wave height (Hs) and mean wave period (Tm) have increased significantly over the Bering Sea in July and August and over the Canadian Beaufort Sea westward to the northern Bering Sea in September, and that the 1992-2013 trends in September mean Hs agree well with satellite-based trend estimates for 1993-2010. Most outstandingly, the regional mean Tm has increased at a rate of 3%-4% yr-1 of the corresponding 1970-99 climatology; it has more than tripled since 1970. Also, the regional mean Hs has increased at a rate of 0.3% to 0.8% yr-1. The trends of lengthening wave period and increasing wave height imply a trend of increasing wave energy flux, providing a mechanism to break up sea ice and accelerate ice retreat. The results also show that changes in the local wind speeds alone cannot explain the significant changes in waves. The wind speeds show significant increases over the Bering Sea to the north of Alaska in July and over the central part of the domain in August and September, with decreases in the region off the Canadian coasts in August. In the region west of the Canadian coast, the climatological mean wind direction has rotated clockwise in July and August, with the climatological anticyclonic center being displaced northeastward in August. © 2015 American Meteorological Society.

Dietrich J.C.,University of Notre Dame | Dietrich J.C.,University of Texas at Austin | Westerink J.J.,University of Notre Dame | Kennedy A.B.,University of Notre Dame | And 17 more authors.
Monthly Weather Review | Year: 2011

Hurricane Gustav (2008) made landfall in southern Louisiana on 1 September 2008 with its eye never closer than 75 km to New Orleans, but its waves and storm surge threatened to flood the city. Easterly tropicalstorm- strength winds impacted the region east of the Mississippi River for 12-15 h, allowing for early surge to develop up to 3.5 m there and enter the river and the city's navigation canals. During landfall, winds shifted from easterly to southerly, resulting in late surge development and propagation over more than 70 km of marshes on the river's west bank, over more than 40 km of Caernarvon marsh on the east bank, and into Lake Pontchartrain to the north. Wind waves with estimated significant heights of 15 m developed in the deep Gulf of Mexico but were reduced in size once they reached the continental shelf. The barrier islands further dissipated the waves, and locally generated seas existed behind these effective breaking zones. The hardening and innovative deployment of gauges since Hurricane Katrina (2005) resulted in a wealth of measured data for Gustav. A total of 39 wind wave time histories, 362 water level time histories, and 82 high water marks were available to describe the event. Computational models-including a structured-mesh deepwater wave model (WAM) and a nearshore steady-state wave (STWAVE) model, as well as an unstructured-mesh "simulating waves nearshore" (SWAN) wave model and an advanced circulation (ADCIRC) model-resolve the region with unprecedented levels of detail, with an unstructured mesh spacing of 100-200 m in the wave-breaking zones and 20-50 m in the small-scale channels. Data-assimilated winds were applied using NOAA's Hurricane Research Division Wind Analysis System (H*Wind) and Interactive Objective Kinematic Analysis (IOKA) procedures. Wave and surge computations from these models are validated comprehensively at the measurement locations ranging from the deep Gulf of Mexico and along the coast to the rivers and floodplains of southern Louisiana and are described and quantified within the context of the evolution of the storm. © 2011 American Meteorological Society.

Bunya S.,University of Notre Dame | Bunya S.,University of Tokyo | Dietrich J.C.,University of Notre Dame | Westerink J.J.,University of Notre Dame | And 12 more authors.
Monthly Weather Review | Year: 2010

A coupled system of wind, wind wave, and coastal circulation models has been implemented for southern Louisiana and Mississippi to simulate riverine flows, tides, wind waves, and hurricane storm surge in the region.The system combines the NOAA Hurricane Research Division Wind Analysis System (H*WIND) and the Interactive Objective Kinematic Analysis (IOKA) kinematic wind analyses, the Wave Model (WAM) offshore and Steady-State Irregular Wave (STWAVE) nearshore wind wave models, and the Advanced Circulation (ADCIRC) basin to channel-scale unstructured grid circulation model. The system emphasizes a high-resolution (down to 50 m) representation of the geometry, bathymetry, and topography; nonlinear coupling of all processes including wind wave radiation stress-induced set up; and objective specification of frictional parameters based on land-cover databases and commonly used parameters. Riverine flows and tides are validated for no storm conditions, while winds, wind waves, hydrographs, and high water marks are validated for Hurricanes Katrina and Rita. © 2010 American Meteorological Society.

Kennedy A.B.,University of Notre Dame | Gravois U.,University of Florida | Zachry B.C.,Texas Tech University | Zachry B.C.,National Oceanic and Atmospheric Administration | And 8 more authors.
Geophysical Research Letters | Year: 2011

A large, unpredicted, water level increase appeared along a substantial section of the western Louisiana and northern Texas (LATEX) coasts 12-24 hrs in advance of the landfall of Hurricane Ike (2008), with water levels in some areas reaching 3 m above mean sea level. During this time the cyclonic wind field was largely shore parallel throughout the region. A similar early water level rise was reported for both the 1900 and the 1915 Galveston Hurricanes. The Ike forerunner anomaly occurred over a much larger area and prior to the primary coastal surge which was driven by onshore directed winds to the right of the storm track. We diagnose the forerunner surge as being generated by Ekman setup on the wide and shallow LATEX shelf. The longer forerunner time scale additionally served to increase water levels significantly in narrow-entranced coastal bays. The forerunner surge generated a freely propagating continental shelf wave with greater than 1.4 m peak elevation that travelled coherently along the coast to Southern Texas, and was 300 km in advance of the storm track at the time of landfall. This was, at some locations, the largest water level increase seen throughout the storm, and appears to be the largest freely-propagating shelf wave ever reported. Ekman setup-driven forerunners will be most significant on wide, shallow shelves subject to large wind fields, and need to be considered for planning and forecasting in these cases. Copyright 2011 by the American Geophysical Union.

Bacopoulos P.,University of Central Florida | Hagen S.C.,University of Central Florida | Cox A.T.,Oceanweather Inc. | Dally W.R.,Surfbreak Engineering science Inc. | Bratos S.M.,U.S. Army
Journal of Hydrology | Year: 2012

Water surface elevations and daily flows are measured in the St. Johns and Nassau Rivers (north Florida) and reveal a storm event in mid-May 2009 and a sea level anomaly in June and July 2009. In an effort to reproduce these events, wind and tidally driven hydrodynamics are simulated from the deep ocean into the St. Johns and Nassau Rivers using a shallow water equations model. Calibration adjusts spatially distributed Manning's roughness based on modeled-observed discharge. For validation, the model captures the regular tidal fluctuation as well as the hydrodynamic responses of the storm event in mid-May at the six water level gaging stations. At the flow gaging station, the model captures the ebb tendency of the tide as well as a strong perturbation (flood pulse) that occurs because of the storm event in mid-May. © 2011 Elsevier B.V.

Bacopoulos P.,University of Central Florida | Dally W.R.,Surfbreak Engineering science Inc. | Hagen S.C.,University of Central Florida | Cox A.T.,Oceanweather Inc.
Coastal Engineering | Year: 2012

A novel set of measurements of winds, water levels, and currents recorded in September of 2004 captured the landfall of Hurricane Jeanne. The dataset provides a full picture of the meteorology and hydrodynamics associated with Hurricane Jeanne and are used to test the state-of-the-art in numerical modeling of storm surge. A shallow water equations model (ADCIRC) is driven by rigorously modeled winds and astronomic tides to replicate continuous hydrodynamic records at two stations, one in Melbourne Beach (Spessard) and the other inside Port Canaveral (Trident Pier), where instrumentation was located by happenstance. Simulation results represent the time-series of water surface elevations measured in the open coast off Melbourne Beach (Spessard) within 0.05. m root mean square error and within 12% of observed maximum surge elevation (1.35. m simulated vs. 1.52. m measured) and exhibit details induced by a 'loop' performed by the hurricane before it made landfall. Prediction of water levels inside Port Canaveral (Trident Pier) is to within 0.06. m root mean square error and includes the observed forerunner and peak surge of the hurricane. In regard to nearshore currents off Melbourne Beach (Spessard), the timing of a sudden switch in the direction of the measured (longshore) current is replicated well with the magnitude of the peak current simulated to within 14% of observation (0.96. m/s modeled vs. 1.11. m/s measured). The capability to accurately simulate the tidal and storm surge hydrodynamics during Hurricane Jeanne provides confidence in using this class of shallow water equations models in coastal engineering practice. © 2011 Elsevier B.V.

Cardone V.J.,Oceanweather Inc. | Cox A.T.,Oceanweather Inc.
Advances in Hurricane Engineering: Learning from Our Past - Proceedings of the 2012 ATC and SEI Conference on Advances in Hurricane Engineering | Year: 2013

Methods of analysis and modeling of the distribution of surface winds about tropical cyclones have increasingly recognized the deficiency of the classical representation of the radial distribution of (e.g. Rankine vortex, Holland profile) of a linear increase of wind speed from the center to a single and tight radius of maximum and a sharp decay to the ambient flow. Newer analysis schemes and parametric and dynamical models now attempt to allow for more complex radial distributions including the possibility of multiple radial wind maxima and storms with indistinct radial maxima and shelf-like profiles extending far into the ambient flow. This paper demonstrates the rather high degree of skill with which a representation of the radial pressure profile with a double exponential form within the initialization scheme of the widely applied TC96 steady state planetary boundary model (PBL) succeeds in modeling such wind field complexities as well as the large range of wind field spatial scales associated with have come to be known as compact, incompact and annular cyclones, and in representing the life cycle of storms that undergo rapid dynamic transformation in wind structure associated with the eye-wall replacement cycle and transitory storm encounters with land masses. Examples are drawn from recent well monitored U.S. Gulf and East Coast historical hurricanes, but the characteristics demonstrated appear to apply to tropical cyclone worldwide. © ASCE and ATC 2013.

Cardone V.J.,Oceanweather Inc. | Cox A.T.,Oceanweather Inc.
Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE | Year: 2011

This paper addresses two questions critical for the successful real world application of the Cooperative Research on Extreme Seas and their Impact (CresT) Joint Industry Project(JIP) design methodology in harsh operating environments: (1) how accurately may very extreme sea states (VESS) be specified by modern numerical spectral wave models? About 20 storms in which VESS (defined as with significant wave height ( HS) > 14 m) have been measured by various in-situ and satellite-mounted altimeters are hindcast and it is shown that when the meteorological forcing is accurately specified, a proven 3rd generation (3G) wave model provides skillful and unbiased specification of peak HS and by implication of the associated spectral properties. The second question addressed is: how do current 3G models behave when applied to even more extreme meteorological forcing than observed in the real storms studied? The same hindcast methodology is, therefore, applied to a population of synthetic hurricanes whose combinations of intensity and scale are predicted by deductive modeling studies of Gulf of Mexico hurricanes carried out following Hurricane Katrina (2004). The model results suggests that for a tropical cyclone to generate say peak HS > 20 m would require the peak wind intensity of a major hurricane (Category 3 or greater) combined with a larger size and faster translation speed than may be maintained by a tropical cyclone in tropical or subtropical settings. Large scale cyclonic and relatively rapidly translating storms with major hurricane force peak wind speeds indeed exist as a class of mid-latitude extratropical cyclones, dubbed "winter hurricanes". Hundreds of such storms have been detected in global satellite altimeter data in virtually all major ocean basins. The peak sea states in the most extreme examples are also found to be simulated quite skillfully with the hindcast technology applied. The hindcast results are explored to infer the upper limit to the naturally occurring dynamic range of sea states in tropical and winter hurricanes. Copyright © 2011 by ASME.

Hagen S.C.,University of Central Florida | Bacopoulos P.,University of Central Florida | Cox A.T.,Oceanweather Inc. | Cardone V.J.,Oceanweather Inc.
Journal of Coastal Research | Year: 2012

Hagen, S.C.; Bacopoulos, P.; Cox, A.T., and Cardone, V.J., 2012. Hydrodynamics of the 2004 Florida hurricanes. We studied the hydrodynamic response caused by the four major hurricanes that struck Florida's coasts in 2004: Charley, Frances, Ivan, and Jeanne. A large-scale, shallow-water-equation model was applied so as to simulate wind and tidally driven hydrodynamics from the deep ocean into the shelf and coastal waters of Florida. Hurricane Ivan served as the calibration case, where the adjusted parameter was the wind drag coefficient. We identified an "increased" wind drag coefficient to perform best and suggest it as a first approximation to the wave contribution to the hydrodynamics. The increased drag coefficient is offered to the consulting and/or forecasting communities, who are frequently without wave-modeling resources, as a pragmatic approach to approximate for waves. Hurricanes Charley, Frances, and Jeanne serve as the validation cases in which the increased wind drag coefficient was applied. Analysis was performed by inspection of maximum water-surface elevations, which are interpreted in terms of shelf and bay dynamics for the west coast hurricane cases (Charley and Ivan) and in terms of channel hydraulics for the east coast hurricane cases (Frances and Jeanne). We conclude that the broad shelf off Florida's west coast allows the storm tide to accumulate along the open coast and that the embayments further magnify the storm tide, and that the Atlantic Intracoastal Waterway along Florida's east coast is effective in propagating storm tide, where we show compartmentalization of the storm tide in the Indian River lagoon as caused by the flow impediment of the causeway abutments. © the Coastal Education & Research Foundation 2012.

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