Karteikarten
Oceans
Karten in diesem Stapel (75)
- 1what equation/law describes the principle of conservation of mass in a fluid?the continuity equation
- 2What is Western intensification?The strengthening of ocean currents on the western side of ocean basins - due to the coriolis effect
- 3What is the coriolis effect?Phenomenon resulting from the rotation of the earth, in which winds and currents travelling towards or away from the equator are deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. - effect helps to explain direction of prevailing winds/existence of gyres
- 4What is Geostrophic flow?It is a current within the atmosphere in which coriolis force and the pressure gradient are in balance. high/low atmospheric pressures/ocean currents such as the kuroshio/gulf stream are almost all geostrophic flows
- 5What is the Ekman effect?Tendancy for wind or current to cause air or water above or below it to move, but in a different direction to the original wind or current. Results from the rotation of the earth.
- 6what is El NinoPhenomenon by which the waters of the eastern pacific off south america become earmer than usual every 4-7 years.
- 7What is the El Nino Southen Oscillation?A worldwide variation in the earths climate pattern and ocean circulation, including the El nino phenomenon associated with a change in position of warm surface waters in the east pacific.
- 8what is La Nina?opposite of El Nino in which the eastern pacific waters are usually cold
- 9what is a halocline?A boundary between waters of different salinities. across which salinity changes rapidly.
- 10mixed layerThe upper layer of the ocean that iss kept mixed by winds and currents, so that its temperature and chemical characteristics are roughly uniform throughout.
- 11what is a neap tide? what causes it?The tide with the smallest range within an approximately 2 week cycle- caused by the gravity the gravity of the sun partly cancelling out the effect of the moon.
- 12What are the most common ions that make up the salt within the oceans?Most common: sodium and chloride ions (make up 85% by mass of all salt in the sea)
the other 15% is made up mainly of Sulphate, Magnesium, Calcium and Potassium - 13What is the Source of the salt in the oceans?- dissolved out of rocks on the land by the action of rainwater/carried in rivers to the sea
-the emanations of hyrdrothermal vents, in dust blown off the land, or volcanic ash - 14what is residence time?The time that an ion remains in seawater before it is removed - common ions in seawater have long residence times. ranging from hundreds of years to hundreds of millions of years
- 15what are the main gases dissolved in seawater?Nitrogen (N)
oxygen (O2)
Carbon Dioxide (CO2)
(the levels of O2/CO2 vary in response to the activities of photosynthesising organisms (e.g.phytoplankton) and animals. - 16How does oxygen level change with depth in the ocean?-oxygen levels are normally highest near the surface due to gas being absorbed from the air/photosynthesis
-concentration drops to a min at around 1000m - consumed by bacterial oxidation of dead organic matter/feeding
- 02 level increases again as you get deeper - 17how does carbon dioxide concentration change with depth within the ocean?Carbon dioxide levels are highest at depth and lowest at the surface, where the gas is taken up by photo synthesizers faster than it is produced by respiration.
- 18Temperature in the ocean:Tropics/subtropics - solar heating keeps ocean surface warm throughout the year
below surface - temp declines steeply to 8-10 degrees at around 1000m (thermocline)
deeper - temp decreases to gradually to a uniform temp of around 2 degrees - subsists throughout oceans. - 19salinity in the oceans:- averages at around 35g of salt per kg (ppt)
- varies considerably - depends on factors/processes operating at that location
- low salinity - high rainfall, river input, melting
- High salinity: evaporation/ice formation - 20where is surface salinity highest/lowest?- surface salinity highest in the subtropics where evaporative losses of water are high - enclosed or semi enclosed basins (such as the Med)
- lowest in colder regions or where there are large inflows of river water - 21Pressure in the oceans:- measures in bars
- sea level - weight of atmosphere exerts pressure of 1 bar
- underwater pressure increases 1 bar per 10m (e.g. 80m - 9 bars) - 22Density in the oceans:- depends on temp/salinity
- decrease in temp/increase density
-increase in salinity/increase density
-density increases with depth - 23North Atlantic deep waterCold, dense water, forms and sinks in the north atlantic, then moves south
- 24Atlantic intermediate watercool layer of intermediate density, forms and sinks in north atlantic, then moves south
- 25Atlantic central waterWarm, low density surface waters in the tropics/subtropics
- 26Antarctic Intermediate watercool layer of intermediate density, sinks and moves north
- 27Antarctic bottom waterColdest and densest layer, forms close to Antarctica, sinks then moves north
- 28prevailing winds:- winds produced by pressure differences/modified by the coriolis effect
- 29ocean gyres- combination of prevailing winds and Ekman transport produces large scale circular systems of currents
- 2 in each of Atlantic/Pacific oceans/1 in indian ocean - 30Boundary currents - east and west- currents at the edges of gyres
- west - strong, narrow, warm - move heat energy away from the equator.
- east - weak, broad, cold - move water back towards tropics
- gyre boundaries at equator - warm west flowing equatorial currents - 31examples of eastern boundary currents?- Benguela current off southwest africa
- California Current - 32Examples of western boundary currents?- Gulf stream
- Brazil current in southwest atlantic - 33Meeting of currents: examples:- e.g. gulf stream (warm) with labrador current off eastern seaboard of USA/canada (cold)
- denser water (cold) dives beneath warm current - produce turbulence. Can trigger upward flow of nutrient rich water from sea floor encouraging growth/creates feeding ground - 34What is downwelling?-caused by thermohaline processes
- warm, salty water carried by surface current into arctic ocean it rapidly cools where it meets colder, less salty, polar water - as it cools, density increases and it sinks down - 35Coastal downwelling:- winds blowing towards equator on western side of oceans push seawater towards land by ekman transport. As reaches coast it is forced down.
- 36What is upwelling?- The upward motion of deep ocean water towards the surface. Some upwelling increases ocean fertility by recirculating nutrients from deeper layers
- 37example of upwelling (coast):- winds blowing towards the equator on eastern side of oceans push seawater away from land by ekman transport so deeper water must upwell near the coast to replace it
- 38Global Conveyor:- driven by water sinking in major downwelling zones
- Starts with cold, salty water sinking in north atlantic. moving south at depth - flows round antarctica branching into indian/pacific - returns to surface by mixing with warmer water above. warm surface currents return to atlantic - 39ocean basins..
- 40mid ocean ridges..
- 41What is the approximate depth of the worlds oceans?3,800m
- 42What is the typical value of the gradient of the continental slope?4 degrees
- 43What term is used to denote a region of rapid change in density with depth?Pynocline
- 44what is the approximate timescale associated with the global thermohaline circulation?1000 years
- 45In an Ekman spiral what direction is the surface flow of water relative to the wind?45 degrees to the right in the northern hemisphere
- 46what are tides with 2 unequal high waters and two unequal low waters each day called?semi-diurnal mixed tides
- 47what is the time interval between successive high water levels for a lunar semi diurnal tide?12 hours 25 minutes
- 48Spring tides:- may occur shortly after new moon
- occur roughly once every 2 weeks
- they are times when tidal ranges are relatively high
- they occur at conditions of syzygy - 49what name is given to lines on a chart joining locations sharing the same tidal range?co-range lines
- 50what does the speed that a linear water wave crest travels at in shallow water depend upon?The water depth
- 51waves travelling towards a beach tend to.....refract and focus their energy on headlands
- 52What is the Primary mixing process in a salt wedge estuary?Entrainment - The mixing at the boundary between fresh and salt water causes the surface layer to entrain salt water and become more saline as it moves toward the sea. To compensate for the entrained salt water, there is a slow movement of the salt water up the estuary at depth.
- 53If the variation of a quantity 'y' in time 't' is described with the function y=e ^ -2t'y' decreases exponentially with time
- 54in what sea areas is a surface salinity of around 18-22 ppt likely to be found naturally?the black sea
- 55how does the deep atlantic water change as it travels to the deep pacific ocean?The deep pacific water has a higher concentration of nutrients and lower concentration of oxygen
- 56what is the depth at which calcium carbonate shells are almost all completely dissolved called?Carbonate compensation depth
- 57how to describe the water emitted from hydrothermal vents in the deep sea?- Hot
- Anoxic
- Metal rich - 58what increases the oxygen concentration in surface seawater?Photosynthesis
- 59To what does nitrogen fixation refer?Conversion of nitrogen gas to ammonia and nitrate
- 60what is the principle source of magnesium in seawater?- Fluvial input
- 61what is the volume of the ocean?1,335,040 x 10^3km^3
- 62what are sediments that are derived from the land called?Terrigenous
- 63What is an example of an element that behaves in a similar way to caesium?Lithium
- 64At what depth do you expect to find the oxygen minimum concentration in the open ocean?0.5 - 2.5 km below the surface
- 65manganese nodules:- they grow at a rate of a few mm per million years
- typically size/shape of a potato
- usually found on the abyssal plain
- combined concentration of nickel, cobalt, and copper can exceed 3% by weight - 66halogens- fluorine
- Iodine
- Chlorine
- Bromine - 67What is the correct oxidation number for nitrogen in NH3 ammonia is?-3
- 68if the gases in a mixture do not react...- the total pressure of a gas mixture is the sum of the partical pressures of the individual gases in the mixture
- at a constant pressure the volume of a fixed mass of gas is directly proportional to its temp in kelvin
- at a fixed temp and pressure the volume of a gass is proportional to the number of moles present - 691 mole of an ideal gas at 20 degrees C and 1 atmospheric pressure has a volume of?24 dm^3
- 70Given that the atomic number of carbon is 6, an atom of the carbon -14 isotope contains...8 neutrons, 6 protons, and 6 electrons
- 71at sea level what temp does pure water boil at?373k
- 72what temp does pure water freeze at?273k
- 73At what temperature is water at its most dense?4 degrees C
- 74The ability of an atom to attract a pair of shared electrons in a covalent bond is called the ....... of the atom?Electronegativity
- 75—
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- Beschreibung
- OceanScience102 Karteikarten am Oceans, erstellt von Kizzy Lev am 14/01/2020.
- Erstellt von
- Kizzy Lev
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