history of oceanography Flashcards
what is the degrees of latitude
line goes from left to right (measures north to south)
what is the degrees of longitude
line goes from top to bottom (measures east to west)
what is 1 degree of latitude
130km wherever you are on the planet
what is 1 degree of longitude
130km – the 1 degree compresses and becomes smaller as you move you move north or south of the equator
what is 0 degree of longitude
datum point
what does Polynesian map 1500BC show
direction of winds, wave patterns (crossing lines) + islands
- When waves hit land they diffract and bend around them – interference patterns
- become apart of research done today
what is the old technique for Navigation in latitude and what does it look at
using your hand and stars to look at distance between horizon + polaris in the sky – get indication of how far north or south you are
- north (+), south (-)
what is the new method for Navigation in latitude and what does it look at
sextance - measure angles of things from the horizon
Latitude = angle between horizon + the sun at midday
how to use time to do longitude navigation and how did it come about
The Longitude Act 1714 - John Harrison’s sea clock
- Use sextance to determine when the sun is at its highest point in the sky
- Based on that you know when its midday where you are + what time it is in Grenich – use difference in time to calculate how far the earth has spun in that period
- 1 hour = 15 degrees of longitude – allows to accurately pinpoint where you are on the chart
who was involved in the classical era of tides
Aristole
Pytheas of Massalia
The Venerable Bede
Simon Stevin
Isaac Newton
what did aristole discover in the classical era
Noted semi-diurnal tidal variation - Suggested this was due to weather
what did Pytheas of Massalia discover in the classical era
Travelled into the North Atlantic - Observed changes in tidal variation in different places
what did The Venerable Bede discover in the classical era
Author of the Ecclesiastical History of the English People - Reported that tidal heights and times vary between places
what did Simon Stevin discover in the classical era
Dutch scientist - Explained the timing of tides using the phases of the moon
what did Isaac Newton discover in the classical era
Author of Philosophiæ Naturalis Principia Mathematica
Explained tides using gravitation (moon pull)
what are the 3 ages of empires
Chinese exploration
vikings
the age of discovery
what was the Chinese exploration
- Voyages primarily coastal
- Invention of the compass in the 11th centaury AD
- Considerable use of the seasonal changes of wind due to monsoons
- Early production of functional navigational charts (main focus = land)
what were the vikings
- Trade and settlement
- Extended voyages around the North Atlantic
- Limited pillaging!
what was the age of discovery
- Government funded exploration
- Opening trade routes
- Conquest
- Novel resources
what is the age of empires an indication of
how the affects of movement of things by trade can affect things on an anthropogenic basis e.g. “tea” (transported by sea) or “cha” (transported by land)
what was the Pax brittania
- Period of exploration – had boats etc to do so
- Most famous = Darwin – natural selection based on Beagle (1831-183)
what was The Challenger expedition (1872–1876)
- The birth of modern oceanography
- Vessel went out and spent 4 years touring and visiting various parts of the british empire
4 objectives of The Challenger expedition (1872–1876)
- To investigate the physical conditions of the deep sea in the great ocean basins icl depth, temperature, circulation, specific gravity and penetration of light
- To determine the chemical composition of seawater at various depths, the organic matter in solution and the particles in suspension
- To ascertain the physical and chemical character of deep-sea deposits and the sources of these deposits
- To investigate the distribution of organic life at different depths
Equipment on HMS Challenger
Dredge – similar to beam trawl
Grab samples of sediment
Plankton trawls
Long boats
what were the outputs of The Challenger expedition
- > 350 sample stations
- Nearly 500 depth soundings
- > 130 deep sea dredges
- > 4500 new species described
- Confirmed hypothesis of continental drift
- Derived charts of sea temperature, salinity and current movements
- Mapped the Marianas trench and identified its deepest point (Challenger deep)
benefits of oceanography work in 20th century
- Much of the finding in this time was supplemented by military investment
- During the cold war, an understanding of temperature structures + water movement was vital to allow for detection of submarines
- Campaigns to measure these parameters have been piggy backed on to make use of resources, supporting most of the oceanographic work of the last 100 years
explain ocean formation
- was believed that the surface of the planet had not changed since its formation 4.5 billion years ago
- In the late 1800s and early 1900s, Antonio Snider-Pellegrini and Alfred Wegener considered coastal morphology + similar geological structure of the coast of South America and Africa
- In 1915 he suggested the concept of ‘continental drift’, but suggested that his was due to the spin of the earth
- Development of evidence resulted in the development of the theory of plate tectonics resulting in oceanic creation
how did making use of mistakes prove beneficial
shoes 1990
- boat going between japan + amercia lost a container full of shoes
- Helped us understand how surface waters moved around based on where they had washed up
ducks 1992
- Similar thing with rubber ducks happened with a boat going between hong kong + america
21st century oceanography characteristics
- We are becoming more aware of humankind’s impact on oceans - understanding these allow us to predict what may happen and what we can do to ameliorate problems
- increasing our exploitation of the resources that the ocean can provide by using technologies e.g. submarines, satellites to feed into models e.g. use it to predict temp in different environments and conditions
