History of Oceanography II September 2008 Text Website:

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History of Oceanography II September 2008 Text Website: www.mhhe.com/sverdrup9e Slide 2 Navigational Tools Latitude/Longitude Chronometer Astrolabe, Sextant, and Chip Log Charts/Maps Compasses Echo Sounders Satellites Latin root navis and agere to move or direct Slide 3 Finding Latitude at Sea Used the altitude of the North star and the angle of the ship The angle of degrees what the latitude of the ship Celestial Navigation Slide 4 Slide 5 Finding Longitude Chronometer (1773) Time piece that wasnt affected by gravity Invented by John Harrison Used the difference in time of day from start to current position Normal Pendulum clocks lost 10 minutes per day Off course by 150 miles or more (242 km) James Cook used Chronometer to circumnavigate the globe (1779) New Charts of the World 1884 Prime Meridian made 0 Longitude through Greenwich, England 15 = 1 hour Slide 6 The longitude is directly related to the difference between true local time and Greenwich time: 1 hour time difference = 15 degrees longitude difference Harrison's H1 (built 1729-36). Height 76 cm Weight 36 kg Most of the wheels are made of wood Accurate to within a couple of seconds per day Slide 7 Harrison's Watch H4 Completed in 1759 On two trials across the Atlantic, it determined the longitude within 10 nautical miles Slide 8 H1 H3 H4 Harrisons Chronometers Slide 9 Mariners Compass Early form of the magnetic compass Formed 32 points Mariners thought that compass was wrong Didnt understand magnetic variation of compass at the time Angle between magnetic north and true north Used to determine where wind was coming from when sun was down Early Chinese first to use compass ~1040 AD Loadstone/Magnetite Slide 10 Diagram of a Ming dynasty mariner's compass Slide 11 Slide 12 Nautical Maps/Charts ~ 13 th Century Emergence of Maps and Charts of open water Ptolemys map 127 AD Polynesian Stick Maps Slide 13 Ptolemy's World Map - 150AD Slide 14 Charting Currents 1777 Benjamin Franklin Gulf Stream Map 1806 Matthew Maury Father of Modern Oceanography US Navy Cataloged wind and currents of ocean 1855 Wrote: The Physical Geography of the Sea Slide 15 Slide 16 Astrolabe, Sextant, and Chip Log Astrolabe Dates back to Greece Helped to tell time ~ 15 Century Used to determine latitude Altitude of the stars was taken Angle Slide 17 Astrolabe in use.For a sun sight, the astrolabe was allowed to hang freely and the alidade was adjusted so that a ray of sunlight passed through the hole in the upper vane and fell precisely on the hole in the lower vane. Slide 18 Sextant/Quadrant 1730 Independently Invented John Hadley (English) Thomas Godfrey (American) More accurately measured the angle of horizon and stars More accurate latitude Slide 19 Slide 20 Chip Log Speedometer Line containing knots at intervals Counted knots over time Slide 21 Slide 22 Gyroscopic Compass 1907 to present Points always to True North Not affected by metal on hull of ship Uses electricity power Slide 23 Soundings Before soundings, ocean floor thought to be featureless Used hand lines with weights to find depth and features of ocean floor Challenger expedition Canon ball with piano wire Made determining touch easier 1895, only 7000 soundings of deep ocean had been made (2000 m or greater) Slide 24 Echo Sounders ~ 1914 World War I Determines Ocean floor Depth Uses Reflection of Sound waves Primitive sonar 1925 German ship Meteor Charted ocean depth and discovered the mid-Atlantic ridge 1950s first detailed chart of ocean floor Slide 25 Slide 26 Slide 27 Satellites 1978 NASA launches Seasat Sea-surface temperature Surface wind speed and direction Directional wave spectra Satellite included Radar altimeter Wind field scatterometer Microwave radiometer Radiometer operating in visual and infrared 1992 US/France Launch TOPEX/Poseidon Ocean circulations interaction with the atmosphere Slide 28 Slide 29 Radar Altimeter Slide 30 Microwave Radiometer Slide 31 The Future Private/institutional and national oceanographic institutions Observing process that take place Looking at ocean basins with observatories Using ROV and AUV Science of the Deep Slide 32 Slide 33 GPS: Global Positioning System Global Navigation Satellite System (GNSS) Uses 28 earth orbiting satellites, 11,000 mi above Earth, 12 hour orbit around Earth Location Speed/Direction Time Slide 34 Slide 35 Slide 36 Citations http://waterencyclopedia.com/Mi-Oc/Navigation-at-Sea-History- of.html http://waterencyclopedia.com/Mi-Oc/Navigation-at-Sea-History- of.html http://www.riverdell.k12.nj.us/staff/molnar/onotesch1.htm http://en.wikipedia.org/wiki/Compass http://www.mat.uc.pt/~helios/Mestre/Novemb00/H61iflan.htm http://www.allstar.fiu.edu/aero/GSI.htm http://pubs.usgs.gov/gip/dynamic/developing.html http://adsabs.harvard.edu/abs/1978BoLMe..13..393D http://en.wikipedia.org/wiki/Global_Positioning_System http://www.howstuffworks.com/gps.htm 1557 sailors using instruments of navigation.. IRC. 2005. unitedstreaming. 17 September 2008