Transcript History of Oceanography

Anno Accademico 2011-2012
Docente: Renzo Mosetti
[email protected]
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Connected to the
world’s overall history
◦ Commerce, warfare,
resources, weather
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The oceans have shaped
humanity’s past
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Understand how and why people apply
marine sciences today
Oceanography’s history is about people, not
just oceans and test tubes.
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Not sure when ocean voyages actually began
◦ Fish hooks and spears dated approximately 5000
B.C.
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Earliest recorded sea voyage – Egyptians
about 3200 B.C.
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Most important early
Western seafarers
Motivated by trade,
Phoenicians traveled
incredible distances
Established first trade
routes throughout the
Mediterranean and as far
north as Great Britain
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Stayed within sight of land
Traveled at night – steered by observing
constellations and the North Star.
In the ancient world, the North Star was
called the Phoenician Star
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Between 2000 and 500 B.C.
Often traveled thousands of kilometers across open
ocean
Open canoes cut from tree trunks
Developed stick maps with ocean currents
Settled most of the islands in the Pacific Ocean
hundreds of years before Europeans reached Pacific
Ocean
 Earliest
known
regular, longdistance,
open-ocean
seafaring
beyond sight
of land
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First who used mathematical principles and
developed sophisticated maps for seafaring
Pytheas – Greek explorer, noted that he
could predict tides in Atlantic based on
phases of moon
He also measured angle between horizon
and the North Star to determine position –
improved navigation
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2 major contributions
that furthered Pytheas’
work
Calculated Earth’s
Circumference ~40,000
km
Invented first
latitude/longitude
system
Created map of Earth that showed a portion of the
Earth as a sphere on flat paper.
 Produced first world atlas
Improved longitude/latitude system
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◦ System still used today
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Vikings of Scandinavia were active
explorers during The 9th century
Discovered Iceland and Greenland
Leif Eriksson – son of Eric The Red, set off
in search of timber for Greenland Colony
and discovered North America
(Newfoundland, Canada)
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The Chinese Ming Dynasty sent large
convoys of ships out on missions in
which seven voyages were made
There ships were more technologically
advanced than anything in Europe,
consisting of five masts and magnetic
compasses and navigational charts
The Ming Dynasty reached as far as Africa
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Prince Henry the navigator, (1420’s) founded
first school of navigation
Christopher Columbus (1490’s) was
attempting to find a west-ward route to India
when he reached the Bahama Islands
Ferdinand Magellan (1520) led the expedition
that first circumnavigated the word; he was
killed in the Philippines
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Previous exploration driven by military, trade,
or conquest objectives
Royal Navy of Britain launched voyages with
objectives of exploration, mapping and
projecting British presence around the world
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Made 1st accurate maps of many regions
in the ocean w/ new invention
Chronometer invented by John Harrison
Chronometer is a time piece capable of
keeping accurate time aboard ship at sea
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Noted northerly routed ship from Europe took
longer than ships that came by a longer more
southerly route
Learned about gulf stream from nephew, who gave
his uncle a chart
Franklin had the chart printed and distributed to the
captains of mail ships.
They shortened their inbound voyages by avoiding
the current and they shortened their outbound
voyages by using the current.
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Matthew Maury, in charge of the
Depot of
Naval charts and
instruments.
Organized first international meteorological
conference to establish uniform methods
Published a summarized version of data in
first Oceanographic textbook in 1855
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From 1831 to 1836 a naturalist for the HMS
Beagle circumnavigated the southern
oceans and oceanic islands.
Darwin observed birds and other organisms
on isolated islands, most of his research
took place in the Galapagos Islands.
In 1859, his observations were published in
the book “On the origin of Species”.
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John Ross took samples and animals in Baffin bay
(Canada) Later James Ross took samples from Antarctic
ocean bottom at 4.3 Miles
John Ross and James Ross found that there are some
bottom dwelling creatures in Baffin Bay and Antarctic
Ocean. They discovered that deep Atlantic is uniformly
cold.
Forbes – Oceans divided into life-depth zones;
concluded that ocean life decrease as depth increases.
This contrasted with Rosses finings and created dispute
for decades in Britain.
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The expedition covered 79,178 miles.
Directed by C. Wyville Thompson
2 contributions:
◦ Discovery and classification of 4,717 new marine
species
◦ Measurement of record water depth at the Mariana
Trench of 26,847 feet.
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multimillionaire benefactor to oceanography,
especially in the U.S.
1st to use steel cables for deep sea dredging
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Victor Henson solved the problem about
population fluctuations in commercial fish.
Coined the term plankton
He found that cold water is more nutrient
rich, leading to more plankton, and a larger
fish population.
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Fridtjof Nansen set out with a crew of 13 on a
boat called Fram to explore the Artic sea.
His boat became frozen in ice and drifted for
3 years
His drift proved that there was no continent
in the Artic sea.
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Tested his ideas about the direction of ice
drift
Froze a vessel in the polar ice pack and
drifted with it to reach the North Pole
His vessel was called the Fram
The ship remained in the ice for 35 months
Measurements showed that the Arctic was a
deep ocean basin, not a shallow sea
Water and air temperatures were recorded
Plankton numbers were measured
Il periodo “classico” delle ricerche oceanografiche in Adriatico
*Accademia nautica di Fiume: Wolf e Luksch Campagne in Adriatico con le
navi:
NAUTILUS (1874); DELI (1875, 1876, 1877); HERTHA (1880)
*Regio Comitato Talassografico Italiano fondato nel 1909.
campagne con le navi MONTEBELLO e CICLOPE
*Permanente Internationale Kommission fur Erforschung der Adria – 1910
NAJADE (12 campagne); CICLOPE (10 campagne)
Da Wolf e Luksch (1881, 1887)
La sede triestina di ISMAR, fino al 2002 denominata Istituto Sperimentale Talassografico
"Francesco Vercelli" , è una tra le più antiche Istituzioni italiane che si siano occupate di
ricerche oceanografiche e meteomarine. Le sue origini risalgono al 1841, anno in cui
iniziarono a Trieste le osservazioni meteorologiche sistematiche presso l'allora
Osservatorio Marittimo della Imperial Regia Accademia di Commercio e Nautica,
Istituzione governativa dell'Impero Austro-Ungarico. Per questo motivo l'archivio storico
sull'Adriatico, ed in particolare sul Golfo di Trieste, comprende anche dati risalenti alla
fine del secolo XIX.
Dopo la prima guerra mondiale ed il congiungimento di Trieste all'Italia, detta Istituzione
fu assegnata prima al Regio Comitato Talassografico Italiano, poi al Consiglio
Nazionale delle Ricerche (C.N.R.) e successivamente al Ministero dell'Agricoltura e
Foreste, per tornare nuovamente nel 1985 al C.N.R.
E’ presente una ricca ed aggiornata biblioteca di notevole specializzazione che
annovera circa 11.000 ingressi, di cui 3900 di libri ed il rimanente in collane di riviste,
alcune delle quali a partire dall'inizio del 1900. La Sezione possiede inoltre una piccola
collezione di strumenti meteo-marini ed oceanografici d'interesse storico, fra i quali
alcuni reperti appartenuti alla nave "Elettra" di Guglielmo Marconi.
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Nel 1874 fu fondata laSocietà Adriatica di Scienze
naturali;
Nel 1875 viene inaugurata a Trieste la “Imperial Regia
Stazione Didattica e di osservazione zoologica, sede
distaccata dell’Università di Vienna” (quasi coeva della
Stazione Zoologica di Napoli fondata nel 1874 da
Anton Dhorn);
UNA CURIOSITA’
Sigmund Freud dopo la laurea in medicina si recò in
Inghilterra e, successivamente, lavorò in un laboratorio di
zoologia diretto da Carl Friedrich Claus a Vienna e nella
Stazione Zoologica di Trieste dove si occupò di anatomia
e fisiologia animale arrivando a confermare l'esistenza
dei testicoli nel maschio dell'anguilla.
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First drilling ship
Ship came from Germany
Set the standard for multidisciplinary studies
of the Ocean
Mapped the ocean bottom by echo sounding
Meteor sailed for 25 months
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Musée océanographic – Europe
Scripps institution of Oceanography (1st institute in
U.S.) – California
Woods Hole Ocean. Inst. (Boston)
Lamont Geological Observatory - New York
Rosenstiel school of Marine & Atmosphere Sciences Miami
Texas A&M University administered The Ocean
Drilling Program
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German U-boat led to the invention of the echo
sounder to detect submarines
WW2_military performed and supported many
studies on transmission of sound in the ocean
waves, currents, and ocean- floor topography.
After WW2 U.S. government established a Sea
Grant program to fund ocean research
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The Deep Sea Drilling Project (DSDP) was the 1st
large-scale cooperative effort in academic ocean
research
The Glomar Challenger began 1st leg of deep sea
drilling
The deep sea drilling project became the ocean
drilling program (ODP)
The ODP drill ship JOIDES Resolution, which is a
lot larger than the Glomar Challenger, conducted
its first scientific cruise and the JOIDES program
continues today.
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In 1915, Alfred Wegener developed the theory of
continental drift.
◦ He conceived of a single ancient landmass called
Pangaea that began to break 180 million years ago.
Fredrick Vine and Drummond Matthews provided
evidence for sea floor spreading in 1963
◦ They mapped magnetic patterns of the ocean floor,
which showed parallel bands of similarly magnetized
reaches on either side of oceanic mountain ranges.
Which were records of changes in Earth’s magnetic field
over time
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Increased pressure on body cavities and gases dissolved
in body tissues limits duration of dives.
Decompressing is necessary at greater depths because
rapid ascending turns dissolved gases in tissues into
nitrogen. These nitrogen bubbles can stop blood flow.
This is know as the bends and is extremely painful illness
which can be fatal.
◦ To protect oneself, a strict decompression schedule
which includes stopping at different depths
◦ Jim suit allows a person to repair machinery at the
ocean floor at surface pressure
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William Beebe- descended to a depth of
923 meters off Bermuda in a tethered
bathysphere to observe deep-sea life.
Jacques Piccard- designed untethered
vessel Trieste - 1960
Alvin, Sea Cliff- 2 most widely used
submersibles
Japan’s Shinkai- to study microbes in the
deep sea
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The bathyscaphe,
Trieste, descends to
10,915 meters
Into Marianas Trench
Deepest depth in the
ocean
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Factors of manned sub:
◦ Risk to human life
◦ High cost of the systems required
◦ Relatively short time that can be spent making observations
Advantages of ROVs (remotely operated vehicles)
◦ No risk to humans
◦ Can make computer-assisted maps (based on sonar)
◦ Stay down in water for a long time
Autonomous Underwater Vehicles
◦ Programmed to carry out specific data gatherings missions
of long durations without human life
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Jacques Cousteau- began designing and testing
the underwater living chamber in the 1950s
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In the 1970s teams lived undersea chambers for
up to 60 days
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May be placed on ocean floor or suspended
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Can respond and equalize to any pressure
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Sometimes ocean is observed from space; they can
measure temp., ice cover, color, etc.
Seasat A - 1st dedicated oceanographic satellite.
Nimbus 7- mapped phyto-plankton populations
TOPEX/ Poseidon- mapped global sea level and got
data on ocean –atmosphere interaction.
Global Positioning system- allows ship to determine
positions with in a meter
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Secchi diskCore SamplerHydrometerDredgeAlvin-
Determines how transparency of
the water
takes samples of core sediments
Determines the density of the
water
scoops up marine life
famous submarine that explored
deep sea
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Side-scan sonar-
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Current meter-
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Underwater camera
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Flip-
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Purse seine net-
sonar that can scan in all
directions
determines the speed and
direction of the current
camera that can work
underwater
a bottle like vessel that
can flip sideways in the
water
used to capture schools
of fish
Attenzione: ACCURATEZZA vs. PRECISIONE
Precision and accuracy are terms used to describe systems and methods that
measure, estimate, or predict. In all these cases, there is some parameter you wish to
know the value of. This is called the true value, or simply, truth. The method provides a
measured value, that you want to be as close to the true value as possible. Precision
and accuracy are ways of describing the error that can exist between these two values.
Unfortunately, precision and accuracy are used interchangeably in non-technical
settings. In fact, dictionaries define them by referring to each other! In spite of this,
science and engineering have very specific definitions for each. You should make a point
of using the terms correctly, and quietly tolerate others when they use them incorrectly.
As an example, consider an oceanographer measuring water depth using a
sonar system. Short bursts of sound are transmitted from the ship, reflected from the
ocean floor, and received at the surface as an echo. Sound waves travel at a relatively
constant velocity in water, allowing the depth to be found from the elapsed time between
the transmitted and received pulses. As with all empirical measurements, a certain
amount of error exists between the measured and true values. This particular
measurement could be affected by many factors: random noise in the electronics, waves
on the ocean surface, plant growth on the ocean floor, variations in the water
temperature causing the sound velocity to change, etc.
To investigate these effects, the oceanographer takes many successive readings at a
location known to be exactly 1000 meters deep (the true value). These measurements
are then arranged as the histogram shown in Fig. 2-11. As would be expected from the
Central Limit Theorem, the acquired data are normally distributed. The mean occurs at
the center of the distribution, and represents the best estimate of the depth based on all
of the measured data. The standard deviation defines the width of the distribution,
describing how much variation occurs between successive measurements.
This situation results in two general types of error that the system can
experience. First, the mean may be shifted from the true value. The amount of this shift
is called the accuracy of the measurement. Second, individual measurements may not
agree well with each other, as indicated by the width of the distribution. This is called the
precision of the measurement, and is expressed by quoting the standard deviation, the
signal-to-noise ratio, or the CV.
Consider a measurement that has good accuracy, but poor precision; the histogram is
centered over the true value, but is very broad. Although the measurements are correct
as a group, each individual reading is a poor measure of the true value. This situation is
said to have poor repeatability; measurements taken in succession don't agree well.
Poor precision results from random errors. This is the name given to errors that change
each
SPECIFICATIONS
General
Measurement Range
Initial
Accuracy
Typical Stability
Resolution at 24
Hz
Time
Response 1
Conductiv
ity
0 - 7 S/m
(0 - 70 mmho/cm)
0.0003 S/m
(0.003
mmho/cm)
0.0003 S/m
(0.003 mmho/cm) per
month
0.00004 S/m
(0.0004
mmho/cm)
0.065 second
Temperat
ure
-5 to +35 °C
0.001 °C
0.0002 °C per month
0.0002 °C
0.065 second
Pressure
0 to full scale -1400/2000/4200/6800/10,500 m
(2000/3000/6000/10,000/15,000 psia)
0.015% of full
scale
0.02% of full scale per
year
0.001% of full
scale
0.015 second
0.0012 volts
5.5 Hz 2-pole
Butterworth
Low
Pass Filter
A/D Inputs
0 to +5 volts
0.005 volts
0.001 volts per month