180 likes | 260 Views
Coastal Processes. Humans are moving seaward (closer to the water) Ocean is moving landward. Image from http://www.paulo.miamire.com/. Landform changes caused by storm events. LIDAR surveys - Dauphine Island, Gulf Coast of Alabama. Coastal Hazards. Coastal areas
E N D
Coastal Processes Humans are moving seaward (closer to the water) Ocean is moving landward Image from http://www.paulo.miamire.com/
Landform changes caused by storm events LIDAR surveys - Dauphine Island, Gulf Coast of Alabama
Coastal Hazards • Coastal areas • Variable topography, climate, and vegetation • Dynamic area • Convergence of continental and oceanic processes • Often populous (75% of US lives in coastal zone) • Types of Hazards • Tidal floods • Tropical cyclones • Tsunamis • Coastal erosion
“Long term” water level change Sea Level Rise From IPCC AR4 (2007), Physical Science Section, Chp. 5 Contributing factors: Melting of Earth’s ice volume Reconfiguration of Tectonic Plates Thermal Expansion of Seawater
Daily water level change Tides
Storm Surge Episodic water level change
Coastal Hazards • Tropical cyclones • Originate near equator between 8˚N & 15˚S • Typhoon (Pacific) and hurricane (Western Hemisphere) • Effects • High winds (> 75 mph or 120 km/hr) • Flooding – causes most life loss & damage • Storm surge • Heavy rains • Tornadoes • Results • Deaths declining with improved warnings • Property damage- $10 billion from Andrew • Problems • Increasing coastal population • Poor evacuation routes • Inadequate building codes/enforcement
Wind Speed Distribution 160 km >100 km/hr over a region ~160 km in diameter >60 km/hr over a region ~640 km in diameter 640 km
Hurricane Strike Probability Map • Frequency • About 5 per year • Greatest risk • Florida • Texas • Three common tracks • On-shore • Gulf of Mexico • East Coast skimmers
2005 Tropical Storms Storm tracks generally fall into three categories: 1) Atlantic U-turns 2) Gulf coast strikers 3) East coast skirters http://www.nasa.gov/mpg/126449main_katrina_fred_animation.mpg
1999 Tropical Storms – Large Waves Data from Cape Canaveral Buoy and Model Results