It is customary to assume that the System is initially in a State of
equilibrium and V = 0, and S is uniform along the traverse line at the
start of the computational scheme. Thus, computations should be initiated
for conditions prior to the arrivai of strong winds over the Continental
Shelf. Although the real System would seldom, if ever, be in a complète
initial State of equilibrium, errors in assuming it to be are of little
conséquence in the computational scheme after several time steps in the
calculations, because the effects of the forcing fonctions will eventually
predominate.
To demonstrate the computational procedures, the storm surge in the
Gulf of Mexico resulting from Hurricane Camille (1969) is calculated.
Hurricane Camille was an extremely severe storm that crossed the eastem
part of the Gulf of Mexico with the eye of the storm making landfall at
Bay St. Louis, Mississippi, at about 0500 Greenwich Mean Time (GMT) on
18 August 1969. Unusually high water levels were experienced along the
gulf coast during the passage of Camille because of the intense winds and
relatively shallow water depths which extend far offshore. The storm surge
is calculated and compared with the peak surge generated by Camille.
Information published by the U.S. Weather Bureau for Hurricane Camille
in HUR 7-113 (1969) indicates that R = 14 nautical miles and Vp = 13 knots
would be représentative of these values which are assumed to be invariant
while the storm moved over the Continental Shelf. The wind data and track
for Hurricane Camille hâve been published by the Weather Bureau in HUR
7-113A (1970). The track, together with the traverse line used in the
présent calculations, is shown in Figure 3-47. Overwater wind speeds and
directions are shown in Figure 3-48. A profile of the seabed along the
traverse line is shown in Figure 3-49.
Tide records from the région affected by the storm show the mean water
level to be about 1.2 feet above normal before being affected by the storm.
This value is taken to represent the initial water level. The range of
astronomical tides in this location is about 1.6 feet. A constant value of
0.8-foot above MSL is used in the computations;, the final surge hydrograph
at the coast can be subsequently corrected to account for the predicted
variations of the tide. Variations in the initial water level and astronomical tides may be added algebraically to the storm surge calculations
without seriously affecting the final results. The atmosphenc pressure
différence, p - p , is needed for evaluating the pressure setup component, SA„. "üata^given in HUR 7-113 (1969) suggest that po =26.73
inches of mercury and pn = 29.92 inches of mercury are représentative for
the hurricane. Ail of these values are assumed to remain constant for t e
calculations.
«1. and hurricane characteristics provide
The wind data, basin profile, ano nu
ate of the peak stonn surge
the basic information needed in making
ime intervals, distance incréments
Associated with Hurricane Camillecomputational steps to
along the traverse line, etc., are gi
follow.
3-109
equilibrium and V = 0, and S is uniform along the traverse line at the
start of the computational scheme. Thus, computations should be initiated
for conditions prior to the arrivai of strong winds over the Continental
Shelf. Although the real System would seldom, if ever, be in a complète
initial State of equilibrium, errors in assuming it to be are of little
conséquence in the computational scheme after several time steps in the
calculations, because the effects of the forcing fonctions will eventually
predominate.
To demonstrate the computational procedures, the storm surge in the
Gulf of Mexico resulting from Hurricane Camille (1969) is calculated.
Hurricane Camille was an extremely severe storm that crossed the eastem
part of the Gulf of Mexico with the eye of the storm making landfall at
Bay St. Louis, Mississippi, at about 0500 Greenwich Mean Time (GMT) on
18 August 1969. Unusually high water levels were experienced along the
gulf coast during the passage of Camille because of the intense winds and
relatively shallow water depths which extend far offshore. The storm surge
is calculated and compared with the peak surge generated by Camille.
Information published by the U.S. Weather Bureau for Hurricane Camille
in HUR 7-113 (1969) indicates that R = 14 nautical miles and Vp = 13 knots
would be représentative of these values which are assumed to be invariant
while the storm moved over the Continental Shelf. The wind data and track
for Hurricane Camille hâve been published by the Weather Bureau in HUR
7-113A (1970). The track, together with the traverse line used in the
présent calculations, is shown in Figure 3-47. Overwater wind speeds and
directions are shown in Figure 3-48. A profile of the seabed along the
traverse line is shown in Figure 3-49.
Tide records from the région affected by the storm show the mean water
level to be about 1.2 feet above normal before being affected by the storm.
This value is taken to represent the initial water level. The range of
astronomical tides in this location is about 1.6 feet. A constant value of
0.8-foot above MSL is used in the computations;, the final surge hydrograph
at the coast can be subsequently corrected to account for the predicted
variations of the tide. Variations in the initial water level and astronomical tides may be added algebraically to the storm surge calculations
without seriously affecting the final results. The atmosphenc pressure
différence, p - p , is needed for evaluating the pressure setup component, SA„. "üata^given in HUR 7-113 (1969) suggest that po =26.73
inches of mercury and pn = 29.92 inches of mercury are représentative for
the hurricane. Ail of these values are assumed to remain constant for t e
calculations.
«1. and hurricane characteristics provide
The wind data, basin profile, ano nu
ate of the peak stonn surge
the basic information needed in making
ime intervals, distance incréments
Associated with Hurricane Camillecomputational steps to
along the traverse line, etc., are gi
follow.
3-109