110 likes | 352 Views
Prologue: History of Oceanography . Objectives: Know about ocean exploration Understand the major events in oceanography Be able to define oceanography and tell the disciplines within. Disciplines within Oceanography. Define oceanography. Geological oceanography Physical oceanography
E N D
Prologue: History of Oceanography Objectives: • Know about ocean exploration • Understand the major events in oceanography • Be able to define oceanography and tell the disciplines within
Disciplines within Oceanography • Define oceanography. • Geological oceanography • Physical oceanography • Marine meteorology • Chemical oceanography • Biological oceanography • Ocean engineering
HISTORY • Why did man first want to study the ocean? • Early History: • How was 1st knowledge of the sea passed on? • 5000 Bcà copper fish hooks/fishnets • ~2800 BC à trade in the Mediterranean • ~1500 BC à Phoenicians • Extensive trade, used landmarks for reference • By 600 BC Phoenicians had circumnavigated africa • used movement of sun • named directions: Asu, Ereb • at night, used stars for navigation
History, cont. • 1500-500 BC: Arab traiders in Indian Ocean • 900-700 BC: Greeks navigating by land • First cartographers “Oceanus” • Same time: Chinese navigating by sun/stars • First compass
History cont • 3rd century BC: Library of Alexandria built by? • Eratosthenes measured circumference of world = 40,230km; modern = 40,067 • Latitude and longitude established • Ptolemy: 1st atlas • Changed circumference; overestimated Asia, underestimated ocean; no knowledge of American continent
History, cont. What happened to the Library ? Why? • Dark Ages: • Astrolabe used • Sextant • T-shaped device, measured ht of sun/stars using horizon • 1187 **1st compass used (why did the sailors not like the compass?) • Ship building continued to improve
Dark Ages, cont. • 700-1000 AD: Vikings
**Colonized Iceland **Newfoundland (Leif Erikson) **Greenland (Eric the Red) **How did they navigate? • Starved ravens “straight as the crow flies” • N. Atl. Gyre current • seabirds **Raids: European coasts and the near east (Constantinople)
Arabs: access to greek and roman knowledge **first to notice reversing of currents • Chinese • junks • used charts • studied tides and salinity
Polynesians **charts made of . . . **sidereal compass **sea lanes ** other means of navigation **Why did they spread over Pacific? **Double hulled ships
Importance of Charts and Navigation Information • Latitude: how to determine? • Longitude: **needed accurate clock for ships **Britain offered reward **Harrison’s chronometer **how to determine longitude?