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Geography and Oceanography - Chapter 3

Tham khảo tài liệu 'geography and oceanography - chapter 3', khoa học tự nhiên, địa lý phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 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 data a day A Gigabyte of data an hour Hydrographic surveying. Major technology advances in sonar allow for full bottom coverage images of bottom and obstructions. multiple, focused, high-frequency, short wavelength sound beams Multibeam Movies courtesy of NOAA Hydrographic surveying. Major technology advances in sonar allow for full bottom coverage images of bottom and obstructions. 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 3 regions that I am currently working in: Juan de Fuca Ridge - off . | 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, .