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http://www.nasa.gov/mpg/ 126449main_katrina_fred_animation.mpg 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U- turns 2) Gulf coast strikers 3) East coast skirters
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Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Jan 19, 2016

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Page 1: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

http://www.nasa.gov/mpg/126449main_katrina_fred_animation.mpg

2005 Tropical Storms

Storm tracks generally fall into three categories:

1) Atlantic U-turns2) Gulf coast strikers3) East coast skirters

Page 2: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

1999 Tropical Storms

Page 3: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

1999 Tropical Storms – Large Waves

Data from Cape Canaveral Buoy and Model Results

Page 4: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Waves •Always wind, so always waves

•Transfer of energy from a windy area to a narrow coastal band

•General topics to cover:

•(1) Generation•(2) Dispersion and Travel•(3) Shoaling Transformation•(4) Breaking

Page 5: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Sea, Swell, Surf

Page 6: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Supply the bulk of the energy to coastal processes from WIND

Depends on three factors:

Wind Speed – how “fast” the wind blows

Duration – how “long” the wind blows

Fetch – how “far” the wind blows

Wave Generation

Page 7: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Prediction Nomogram

Page 8: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Anatomy - Periodic Waves

•T = wave period•f = wave frequency = 1/T•L = wave length•C = L/T = phase velocity or celerity•H = wave height = water surface displacement•h = water depth

•Can think of waves w.r.t. a spatial framework, or w.r.t. a temporal framework.

•d = horizontal water particle orbital diameter•s = vertical water particle orbital diameter•u = horizontal water particle velocity•w = vertical water particle velocity

Page 9: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Motion of water in waves

•Red dot on the surface - sees the wave form pass, but moves in a circular orbit

•When red dot is at bottom of it’s orbital, it’s in the trough of the wave, when at the top of its orbital, it’s at the crest of the wave

•Orbital size (diameter) decreases with depth

•Waves propagate through the medium

Page 10: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Superposition

•run animation of wave superposition

Page 11: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Formation of Wave Groups

two wave trains of slightly different wave lengths, superposed, can create wave groups

Page 12: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave PropertiesOscillation

Page 13: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

GLY 2030C 13

Wave Transformation

Refraction, convergence, and divergence

Page 14: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Refraction - La Jolla Canyon

Page 15: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Breaking Style

Plunging breakers, spilling breakers (waves of translation)

Page 16: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Breaking

•The release of energy derived from the wind, along a narrow coastal zone - geomorphic work done by wind, really, translated through medium of water.

Page 17: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Breaking – When it occurs?.

Page 18: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Style of Breaking - Illustrated

•Plunging waves (moderate beaches)

•Spilling waves (flat beaches)

•Surging waves (steep beaches)

•First observations recognized that beach slope and wave steepness had something to do with this...

Page 19: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Surf Zone Wave Decay and Energy Dissipation

•Steep, reflective beaches -

•Wave breaking (and energy dissipation) is concentrated through plunging breakers.

•Broken wave surges up the beach as runup.

•Low-slope, dissipative beaches -

•Extensive, wide surf zone over which spilling breakers dissipate energy.

•At any time, several broken wave bores, and smaller unbroken waves, are visible.

•Villano Beach

•Anastasia Island • Wav

e en

ergy

dis

sipa

tion

patte

rn d

epen

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orph

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Page 20: Http:// 2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns.

Wave Speed - Nearshore

•wave speed C = (gh)1/2

•tow-in waves: H = ~8 m

•C = (10 m/s2 * 10 m)1/2 ~ 10 m/s

•~25 mph!

•waves “surfable” by mortals:

•C = (10 m/s2 * 2 m)1/2 ~ 4.4 m/s

•~9 mph!

•How fast does a Laird Hamilton surf?