Geography and Oceanography - Chapter 3 pot

GEO/OC 103 Exploring the Deep …. Today’s Tune “Sink to the Bottom” Fountains of Wayne Labs Start Next Week  Read through labs ahead of time  See your sections and TAs on the web – dusk.geo.orst.edu/oceans/103labs.html Shape of the Seafloor Techniques of Bathymetry - 1  Challenger expedition (1872-1876) -1st systematic bathymetric survey – ocean floor NOT flat - significant topographic relief  German ship Meteor (1920’s) - 1st echosounding survey – sounds travels through water much better – velocity = distance/time – SONAR (Sound Navigation and Ranging) Bathymetry - 2  WWII - U.S. Navy further developed SONAR technology – knowledge of the enemy – knowledge of the ocean  1950’s - 1960’s - single, focused high- frequency, short wavelength sound beam – “wide-beam” bathymetry – sound beam spreads out as it reaches bottom – range of depths - fuzzy estimate single, focused high-frequency, short wavelength sound beam Bathymetry - 3  1970’s - revolution in bathymetric mapping with multibeam bathymetry  multiple, focused, high-frequency, short wavelength sound beams – “narrow-beam” or “multibeam” bathymetry – sound beam stays narrow and focused all the way to the bottom – depths much more precise – e.g., Sea Beam has 16 beams, Sea Beam 2000 has 121, Simrad EM120 has 191 multiple, focused, high-frequency, short wavelength sound beams A Gigabyte of A Gigabyte of data a data a day day A Gigabyte of A Gigabyte of data an data an hour hour multiple, focused, high-frequency, short wavelength sound beams Multibeam Multibeam Movies courtesy of NOAA Bottom Coverage & Data Density by Survey Method Leadline Single Beam Multibeam 1-2 K soundings per survey 500 - 750 K soundings per survey 400,000 – 1,000,000 K soundings per survey Image courtesy of NOAA & UNH [...]... Institution HURL Sub & ROV surveys Ka‘imikai-o-Kanaloa Pisces IV or V HURL = Hawaii Undersea Research Lab ROV= remotely-operated vehicle RCV-150 *Launch iTunesU Sonar Also Used as a “catscan” of oceans to see water structure ABOVE seafloor an “x-ray” of seafloor to see structure BENEATH seafloor – seismic reflection & seismic refraction – low frequency, long-wavelength sound sidescan sonar to get pictures... Lab Oregon Department of Fish & Wildlife Applications for Mapping Tsunami Runup Models -Evacuation Planning Habitat Restoration Shoreline Change Analysis Analyzing Storm Impacts -Coastal Erosion Fisheries Management Commercial Fishing Marine Reserve Design Emergency Response, Impact Assessment Port Security Maps and Visualizations Navigation Products, Services Wave Energy Oil Spill Response, Tracking... long-wavelength sound sidescan sonar to get pictures of seafloor in addition to depth – backscatter strength as opposed to traveltime Sidescan Sonar Image courtesy of USGS Woods Hole DSL-120 Vehicle Image courtesy of WHOI Deep Submergence Lab and Dr.Dan Fornari Image courtesy of USGS Woods Hole . web – dusk.geo.orst.edu/oceans/103labs.html Shape of the Seafloor Techniques of Bathymetry - 1  Challenger expedition (187 2-1 876) -1 st systematic bathymetric survey – ocean floor NOT flat - significant topographic. ocean  1950’s - 1960’s - single, focused high- frequency, short wavelength sound beam – “wide-beam” bathymetry – sound beam spreads out as it reaches bottom – range of depths - fuzzy estimate. single, focused high-frequency, short wavelength sound beam Bathymetry - 3  1970’s - revolution in bathymetric mapping with multibeam bathymetry  multiple, focused, high-frequency, short wavelength