Coastal Processes November 17

Edge Waves produced by the variability of wave energy reaching shore. produced by the variability of wave energy reaching shore. Waves tend to come in groups, especially when waves come from distant storms. For several minutes breakers may be smaller than average, then a few very large waves will break. Waves tend to come in groups, especially when waves come from distant storms. For several minutes breakers may be smaller than average, then a few very large waves will break. The minute-to-minute variation in the height of breakers produces low-frequency variability in the along-shore current. This drives a low-frequency wave attached to the beach, an edge wave. The minute-to-minute variation in the height of breakers produces low-frequency variability in the along-shore current. This drives a low-frequency wave attached to the beach, an edge wave. The waves have periods of a few minutes, a long-shore wave- length of around a kilometer, and an amplitude that decays exponentially offshore The waves have periods of a few minutes, a long-shore wave- length of around a kilometer, and an amplitude that decays exponentially offshore From Stewart

Figure 17.6 in Stewart. Computer-assisted sketch of an edge wave. Such waves exist in the breaker zone near the beach and on the continental shelf. From Cutchin and Smith (1973).

Coastal Processes Wide range of influences – generalizations are difficult Wide range of influences – generalizations are difficult As water gets shallower, frictional processes become more important As water gets shallower, frictional processes become more important In water <50 m deep, bottom and top Ekman layers merge In water <50 m deep, bottom and top Ekman layers merge Non-linearity may be important Non-linearity may be important

Coastal Processes Bottom slope/bathymetry is a major influence Bottom slope/bathymetry is a major influence Time-dependence in winds – direct response of currents Time-dependence in winds – direct response of currents Fresh water input – must be transported across shelf Fresh water input – must be transported across shelf

Coastal trapped waves Already saw Kelvin and edge waves Already saw Kelvin and edge waves Continental Shelf Waves exist because of sloping bottom – also called Topographic Rossby Waves Conserve Potential Vorticity: Continental Shelf Waves exist because of sloping bottom – also called Topographic Rossby Waves Conserve Potential Vorticity: but h changes due to sloping bottom Propagate with shallower water – coast to the right in Northern hemisphere Propagate with shallower water – coast to the right in Northern hemisphere

ω1ω1 ω2ω2 h1h1 h2h2

h1h1 h2h2 h3h3 coast Winds to south of Tampa cause changes here – coastal response at Egmont is integrated effect of winds blowing to the south – all the way to the Keys

Continental Shelf Wave phase speed is given by: Where  is bottom slope, g is acceleration of gravity, f is the Coriolis parameter, R is the Rossby Radius of Deformation, and k x and k y are the cross-shelf and along-shore wave numbers For the West Florida Shelf, c = 8.2 m/s (Mitchum and Clarke, 1986) Hurricane Dennis moved up the shelf at 8.3 m/s

Hurricane Dennis made landfall near Pensacola, FL late on July 10, Unexpected storm surge occurred 140 miles away in Apalachee Bay and was recorded by the COMPS water level system at Shell Point.

Hurricane Dennis forced Continental Shelf Wave up the coast, leading to much higher storm surge at Shell Point than predicted

COMPS water level record, SLOSH Gulf-wide model water level, and tidal prediction from Shell Point, FL, for Hurricane Dennis. SLOSH has been re-configured based on these observations Modeled water level from Morey, et al. (2006) for Shell Point, FL for Gulf- wide model, NE Gulf model, and local (nested) model

Similar forced CSW lead to major flooding in the Tampa Bay area during Tropical Storm Josephine in 1996 Similar forced CSW lead to major flooding in the Tampa Bay area during Tropical Storm Josephine in 1996 To predict Tampa Bay, must predict W. Fla. Shelf To predict Tampa Bay, must predict W. Fla. Shelf Influence of boundary currents – filaments, meanders – “wiggles” in Gulf Stream or Loop Current can inject nutrients onto shelf, transport biogenic properties, etc. Influence of boundary currents – filaments, meanders – “wiggles” in Gulf Stream or Loop Current can inject nutrients onto shelf, transport biogenic properties, etc. VERY nearshore processes – sediment transport in surf zone, etc. VERY nearshore processes – sediment transport in surf zone, etc.

The US Integrated Ocean Observing System and the Gulf of Mexico Mark E. Luther College of Marine Science University of South Florida US-GOOS Steering Committee

IOOS: The US Contribution to GOOS 1 System, 7 Goals Locally Relevant – Nationally Coordinated Benefits Many User Groups Improve the safety & efficiency of marine operations Improve the safety & efficiency of marine operations Improve homeland security Improve homeland security Mitigate effects of natural hazards more effectively Mitigate effects of natural hazards more effectively Improve predictions of climate change & their effects Improve predictions of climate change & their effects Minimize public health risks Minimize public health risks Protect & restore healthy coastal marine ecosystems Protect & restore healthy coastal marine ecosystems Sustain living marine resources Sustain living marine resources Ultimate goal of IOOS is to provide useful products for anyone who makes decisions in coastal regions of the US - see

Architecture Integrated, Multi-ScaleIntegrated, End-To End

Real-time Obs from GTS Feb 2005 Surface Obs – Drifters, Moorings Subsurface Obs – XBTs, Argo, Moorings Global Component of the Observing Subsystem Integrate Remote & In Situ Sensing An International Collaboration

Coastal Component – A System of Systems Approach Provides data & info required by regions Reference & sentinel station-network Data standards & exchange protocols Operated by NOPP Agencies & RAs Designed & operated by Regional Associations Involve user groups in design & evaluation of the IOOS  Resolution  Variables Based on user needs for data & information Regional COOS’s National Backbone Ultimate goal of IOOS is to provide useful products for anyone who makes decisions in coastal regions of the US - see

Observing Systems in Florida are building blocks of both the Southeast Atlantic Coastal Ocean Observation Regional Association (SECOORA)/Southeast Atlantic Coastal Ocean Observing System (SEACOOS) and the Gulf of Mexico Coastal Ocean Observing System (GCOOS) – see and SEACOOS

GCOOS Activities Formally established by Memorandum of Agreement in January 2005 – At present, there are 41 signatories to the MOA Board of Directors Elected in June 2005 Board meets Aug in Houston Business Plan drafted and will be refined/approved by Board Workshop for Oil and Gas Production and related industries Nov. 2-4 in New Orleans IOOS and Public Health Workshop Jan in St. Petersburg

GCOOS Board of Directors: Private Sector representatives Cortis Cooper, ChevronTexaco Alfred Prelat, The Boeing Company Raymond Toll, Science Applications International Corporation Jan van Smirren, Fugro GEOS Governmental representatives Robert (Buzz) Martin, Texas General Land Office Chris Oynes, Minerals Management Service Don Roman, University of Southern Mississippi Academic representatives Mark Luther, University of South Florida Worth Nowlin, Texas A&M University Nancy Rabalais, Louisiana Universities Marine Consortium Education and Outreach representatives Mike Spranger, Florida Sea Grant Program Sharon Walker, J.L. Scott Marine Education Center & Aquarium