Oceanography Flashcards with Answers
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What is the difference between conclusions drawn using the scientific method vs. those reached on non-scientific grounds?
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Scientific method observes a phenomenon and asks a question, generates a hypothesis and predictions, experiments to test the hypothesis, and then draws a conclusion.
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What are the consequences of the high heat capacity of water for climate?
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Water absorbs a lot of heat with small increases in temp; releases a lot of heat with small decreases in temp which is a big deal for climate stability
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What is a conservative vs non-conservative property of seawater?
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Conservative: Properties that can only be altered at the sea surface (temp, salinity, inert gases, [Na+], [Cl-], properties not altered by biological or geochemical reactions. Non-Conservative: Properties that can be altered anywhere in the water column, opposite of conservative
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What is latent heat?
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a) Is energy released or absorbed by a body or thermodynamic system b) When water undergoes a change of state, large amount of heat is absorbed or released c) Amount of heat absorbed or released is due waters high latent heats d) Latent means hidden
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Why are water molecules attracted to each other, and what impact does this have on the physical and chemical properties of seawater?
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Water Molecules have polarity a) They orient themselves relative to one another b) Positively charged hydrogen area of one water molecule interacts with a negatively charged oxygen end of adjacent water molecule c) Hydrogen bond between water molecules are weaker than the covalent bonds that hold individual water molecules together d) This hydrogen bond are strong enough to cause water molecules to stick to one another and exhibit cohesion e) This gives water surface tension f) Water molecules also stick to other polar chemical compounds g) Water moelcules can reduce the attraction between ions of opposite charges by 80 times
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What are some of the major physical properties of water?
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a) Only substance that is found on earth as solid liquid and gas b) Water has a high specific heat capacity c) Water has high latent heat d) Water has very unique density. Ice floats on water e) Cohesive behavior f) Great solvent power for ionic substances g) Cannt dissolve molecules that are non-polar
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Which state of matter is USUALLY the densest? In which material is this the exception?
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Solid, liquid water is exception, denser than ice
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How does salinity vary generally with latitude? Depth?
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Salinity lower at high and low latitudes, high around 0 latitude. Salinity increases with depth
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Why are the oceans salty?
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Chemicals leached from rocks in the other layer, volatile chemicals from the interior and volcanoes which would have been salty early on. More salts accumulated in oceans as rocks broke down by erosion
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What are two possible sources of water on Earth?
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Rain and water-rich minerals in meteorites
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How does the Coriolis Effect affect the circulation of the atmosphere? How does it affect the circulation of the ocean? How would the circulation of the oceans and atmosphere differ if the Earth didn't rotate? How about if it rotated in the opposite direction?
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3 cells per hemisphere: Polar - Active (updraft on hot side, downdraft on cold side), Ferrel - Passive (downdraft on hot side), Hadley - Active (updraft on hot side, downdraft on cold side). Latitudinal winds: 0-30 Trade Winds, 30-60 Westerlies, 60-90 Polar Easterlies. Accelerates ocean currents, frictional drag so speed of water is reduced. If Earth didn't rotate currents wouldn't move 45 degrees relative to forcing wind, "ekman" response. The atmosphere would circulate between the poles and the equator in a simple back-and-forth pattern.
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Describe the types of ocean currents.
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Equatorial Currents: Found on either side of the equator, flow to the west. Boundary Currents: Western: Carry warm water from tropics poleward on west ocean basins, Eastern: Eastern side of ocean basins, flow equatorward transporting cold water from high to low latitudes. All these currents in the North/South Pacific/Atlantic gyres South Surface currents: Make up 10% of water ii) Upper 400m of ocean Deep Water currents: 90% of the ocean Move around the ocean basins by density forces Density is relational to temperature and salinity Wind Driven Currents Ekman transport: 90 degrees to right in North Hem 90 degrees to the left in south hem
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What is upwelling and why does it occur?
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Deep, cold water rises toward the surface due to winds blowing across the ocean surface pushing water away, and water then rises up from beneath the surface to replace the water that was pushed away. Occurs in the open ocean and along coastlines
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What is the difference between western and eastern boundary currents?
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Eastern Boundary Currents: Shallow, broad and slow-flowing. Found on eastern side of oceanic basins, flow equatorward transporting cold water from higher to lower latitudes. Western Boundary Current: Warm, deep, narrow, fast flowing currents on west side of ocean basins. Carry warm water from tropics poleward.
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What is a gyre?
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Large system or rotating ocean currents involving large wind movements caused by the Coriolis Effect. Main gyres: Indian Ocean Gyre, North and South Atlantic Gyres, and North and Pacific Gyres
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How does surface salinity vary with latitude? Why does it vary the way it does?
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High and low latitudes have lower salinity, and mid latitudes have higher salinity because it's hotter and water evaporates. At high and low latitudes melting icebergs and sea ice also decrease salinity
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Why does it rain a lot in the tropics? Why are the deserts in the subtropics?
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The equator is an area of low atmospheric pressure because it receives the most sunlight out of any place on Earth. This means that the level of evaporation is higher, and therefore there is more moisture in the atmosphere. This low-pressure system creates storms with large amounts of precipitation. Northern and Southern Hadley cells, a system of air and water vapor circulation near the equator, converge at the intertropical convergence zone (ITCZ), moving from 23 degrees N to 23 degrees S with season changes. The subtropical deserts center on the Tropic of Cancer and the Tropic of Capricorn. The aridity of these areas is due primarily to the general circulation of air around the Earth. Subtropical areas have consistently high atmospheric pressure because of descending air currents and are swept by hot, dry winds. Such conditions keep moisture-bearing winds from entering the region and prevent the formation of clouds (no water vapor). Without clouds, the land receives nearly the full heating effect of the sun's rays.
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How does salinity vary with depth in the ocean? Why?
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As temperature increases, seawater density decreases due to thermal expansion. As salinity increases, seawater density increases due to the addition of more dissolved material. As pressure increases, seawater density increases due to the compressive effects of pressure.
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What are the three general layers of ocean water?
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Mixed surface layer: occurs above a strong permanent thermocline (and corresponding pycnocline); water is uniform because it is well mixed by surface currents Upper water: the thermocline and pycnocline occur in this relatively low-density layer, which his well developed throughout the low and middle latitudes Deep water: denser and colder; extends from below the thermocline/pycnocline to the deep-ocean floor Thermocline: layer of rapidly changing temperature Pycnocline: layer of rapidly changing density
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What is the origin of ocean salts?
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Wherever water comes in contact with the rocks of Earth's crust, some of the minerals dissolve. This is the source of salts in the oceans, whether from stream runoff or dissolving directly from the sea floor.
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How can seawater's density be altered?
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Density changes due to temperature (largest variability), salinity (~3.5% so modest in variation), and pressure (weakest changes).
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Where can masses of seawater be observed to be sinking? Why?
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Thermohaline circulation is the movement of deep currents, which form at the surface of the ocean in high latitudes (near the poles) where they become cold and dense, so they sink. Density-driven circulation moves water vertically and accounts for the thorough mixing of the deep masses of ocean water. Some surface waters become high in density—through low temperature and/or high salinity—and so sink beneath the surface. This dense water sinks and spreads slowly beneath the surface, so these currents are called deep currents. At high latitudes at the surface, surface water becomes cold and its salinity increases as sea ice forms. When this surface water becomes dense enough, it sinks, initiating deep-ocean currents. Once this water sinks, it is removed from the physical processes that increased its density in the first place, so its temperature and salinity remain largely unchanged for the duration it spends in the deep ocean.
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What is the difference between climate and weather?
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Weather describes the conditions of the atmosphere at a given time and place. Climate is the long-term average of weather.
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What role does water vapor have in the Earth's atmosphere have on climate? On the circulation of the oceans?
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The release of vast amounts of water's latent heat of condensation that is carried within water vapor and is released as water condenses to form clouds in a hurricane power tropical storms. Surface winds feed moisture (in the form of water vapor) into the storm. When water evaporates, it stores tremendous amounts of heat in the form of latent heat of evaporation. When water vapor condenses into a liquid (clouds, rain), it releases this stored heat into the surrounding atmosphere, which causes the atmosphere to warm and the air to rise. This rising air causes surface pressure to decrease, drawing additional warm moist surface air into the storm. This air, as it rises and cools, condenses into clouds and releases even more latent heat, further powering the storm and continuously repeating itself, each time intensifying.
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What role does the atmosphere have on Earth's climate?
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The atmosphere plays a crucial role in the regulation of the Earth's climate. The atmosphere is a mixture of different gases and aerosols (suspended liquid and solid particles) collectively known as air (mostly nitrogen and oxygen). However, green house gases trap heat within the lower atmosphere that is trying to escape to space, making the surface of the Earth hotter (greenhouse effect). The atmosphere does not operate as an isolated system. Ocean currents move heat from warm equatorial latitudes to colder polar latitudes. Heat is also transferred via moisture (water vapor). Water evaporating fro mthe surface of the oceans stores heat which is subsequently released when the vapor condenses to form clouds and rain. The oceans store much greater quantities of heat than the atmosphere.
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How does the angle at which the Sun's rays change with latitude? How does this affect temperatures at those latitudes?
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The amount and intensity of solar radiation received at higher latitudes are much less than at lower latitudes. Sunlight strikes low latitudes at a high angle, so the radiation is concentrated in a relatively small area. Sunlight strikes high latitudes at a low angle, so the same amount of radiation is spread over a larger area. Earth's atmosphere absorbs some radiation, so less radiation strikes Earth at high latitudes than at low latitudes, because sunlight passes through more of the atmosphere at high latitudes.
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What causes the seasons?
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a. The tilt of Earth's rotational axis (and not its elliptical path) causes Earth to have seasons. Earth's axis is tilted at an angle of 23.5 degrees, which causes the Northern and Southern Hemispheres to take turns "leaning toward" the Sun every six months and results in the change of seasons. b. Spring: At the vernal equinox, the Sun is directly overhead along the equator. During this time, all places in the world experience equal lengths of night and day. c. Summer: At the summer solstice, the Sun reaches its most northerly point in the sky, directly overhead along the Tropic of Cancer, at 23.5 degrees north latitude. d. Fall: At the autumnal equinox, the Sun is directly overhead along the equator again. e. Winter: At the winter solstice, the Sun is directly overhead along the Tropic of Capricorn, at 23.5 degrees south latitude
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What is Earth's albedo? What is an example of a high albedo surface? A low albedo surface? How might albedo changes affect climate?
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The albedo of various Earth materials is the percentage of incident radiation that is reflected back to space. The average albedo of Earth's surface is about 30%. More radiation is reflected back to space at high latitudes because ice has a much higher albedo than soil or vegetation. When the planet's albedo or reflectivity increases, more incoming sunlight is reflected back into space. This has a cooling effect on global temperatures. Conversely, a drop in albedo warms the planet
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Why do oceans (or rather large bodies of water) tend to have a moderating effect on coastal areas?
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Oceans and large bodies of water have moderate effects on coastal areas because they alter the temperature, during the day air flows onto land(cooling) and at night the air flows toward the water(heating).
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What types of seasonal temperature differences generally exist for areas farther from oceans?
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Relatively speaking, what is the difference in the amount of heat required to raise the temperature of H20 compared to the amount of heat required to change H20 from one state of matter to another?
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The temp needed to heat water is significantly less than that need to alter its state to a solid liquid or gas
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With respect to water vapor, what does saturation mean?
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With respect to water vapor saturation means the absorbed co2 and o2 in water or air, ( water is more important though)
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What does rising air in the atmosphere tend to do?
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Rising air in the atmosphere tends to cool off and move along the atmosphere and cool off to fall back down.(low pressure rises the hotter air) (higher pressure brings the cooler air down)
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How do air masses move at Earth's surface?
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Air masses on earth's surface (very low and warm) travel away from high pressure areas and are fed by cool air sinking from higher altitudes, and low pressure areas have air flowing towards them and go upward because the air in hotter.
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What are the different circulation cells?
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a. Hadley cell-Around 30 degrees north and south latitude, the air cools off enough to become denser than the surrounding air, so it begins to descend, completing the loop b. Ferrel cell-behaves much as an atmospheric ball bearing between the Hadley cell and the Polar cell, and comes about as a result of the eddy circulations (the high and low pressure areas) of the mid-latitudes. each hemisphere has one between 30-60 degs latitude c. Polar cell- 60-90 degs latitude each hemisphere has one also one.
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What causes the Coriolis Effect? How does it affect the way air circulates around?
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The main cause of the Coriolis effect is the earth's rotation. As the earth spins in a counter-clockwise direction on its axis anything flying or flowing over a long distance above its surface is deflected. Some of the most important impacts of the Coriolis effect in terms of geography are the deflection of winds and currents in the ocean. In the Northern Hemisphere these winds spiral to the right and in the Southern Hemisphere they spiral to the left. This usually creates the westerly winds moving from the subtropical areas to the poles.
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What are trade winds? How do they blow?
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The masses of air that move across Earth s surface from the subtropical high-pressure belts toward the equatorial low-pressure belt constitute the trade winds
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What kind of wind patterns develop on a rotating Earth?
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Because Earth rotates on its axis from west towards the east, air near the surface from the tropics is moved toward a westerly direction [toward the right] in the northern hemisphere.
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How is the Earth's lithosphere different from the asthenosphere?
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The lithosphere(coolest part) is above the asthenosphere(hot enough to melt stuff) and is rigid rather than plastic like the asthenosphere. It is also smaller than the asthenosphere.~100km depth. the lithosphere will break under force where the asthenosphere moves
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Why is the top of the continental crust is usually at a higher elevation than the top of oceanic crust?
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The elevation is because continental crust has low density and is thicker where the oceanic crust has high density so its thinner. density is the main point
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How old are the ocean basins in comparison to the Earth?
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The age difference is huge, the oldest segment of the ocean floor in the western pacific ocean is 200 million years old where the earth is 4.6 billion years old
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How do ocean basins form? How is oceanic crust destroyed?
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Ocean basins are formed by the divergence of tectonic plates where magma rises into the upper mantle and crust, solidifies, and creates new crust. Oceanic crust subducts at convergent boundaries where older oceanic lithosphere subducts under younger lithosphere
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What specific factors control the average surface temperature of a planet?
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The convective heat transfer of the atmosphere, distance from the sun, albedo, and the greenhouse gas effect.
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Why is the Earth's average surface temperature not -18°C but 14.5°C?
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The greenhouse gas effect allows some of the radiant heat from the sun to be captured in the lower atmosphere therefore increasing the average temperature of the earth.
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Based on what you've learned about the controls on climate, why do you think the Earth's average surface temperature been warming rapidly over the past several decades over both the ocean and land.
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Growth in industry, agriculture, and transportation since the Industrial Revolution has produced additional quantities of the natural greenhouse gases which traps more heat in the atmosphere and gradually raises the temperature of the earth.
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Why will temperatures warm over the 21st century?
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Which of the following methods could be used to reduce global warming in the 21st century by affecting the planetary energy balance?
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By decreasing the concentration of greenhouse gases in the atmosphere
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How will ongoing melting of sea ice, glaciers, and ice sheets on the planet affect average surface temperatures on Earth over the next several decades?
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Ocean temperatures will increase because the albedo will decrease therefore more heat will be absorbed.
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Will ocean surface temperatures change by the same amount as land surface temperatures? Why?
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No, the ocean temperatures will not heat up as quickly because water has a higher heat capacity.
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How are ocean temperatures linked to hurricanes?
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The warmer the water is, the more water vapor upon condensing in the atmosphere latent heat is released which warms the surrounding air which causes it to expand and evaporate even more water, creating a process that escalates into a hurricane.
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Why is hydrogen bonding relevant to understanding hurricanes?
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Due to the cohesive behavior of hydrogen bonding, much heat is required to break up the bond, & the molecule evaporates. Evaporated molecules carry the bond-breaking energy with them as latent heat. Latent heat fuels the expansion of the hurricane.
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Given what you've learned about the overturning circulation of the oceans, and the processes that affect deep-water formation, why do you think that ocean currents might change in the 21st century?
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What controls the movement of deep currents in the ocean?
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Density drives deep ocean currents
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Do you think that the deserts (like the southwestern USA and Northern Mexico, and the Sahara Desert) will shrink in the next several decades or will they grow?
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They deserts will grow
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Will the wet places on the planet like the equatorial and sub-polar regions become wetter or drier?
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The climates will get wetter
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What processes can be used to clean up oil?
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Microbial degradation, skimming and burning, photo-oxidation, dispersion, evaporation and dissolution
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Would these processes proceed more quickly in breaking up the oil if the oil spill was in colder waters (i.e., an oil spill in the Arctic Ocean)?
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These process are actually much more difficult in cold waters. a. Significant wave height b. Ice conditions are dangerous c. Temperatures are much colder to work in d. Weather related visibility e. Currents f. Difficult to find and recover oil g. Few properly trained responder personnel h. Equipment difficult to obtain and maintain i. Little Research into extreme cold weather oil spill j. Oil in slush, snow, solid ice, under the ice, broken ice
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Would these processes proceed more quickly in breaking up the oil if the oil spill was in warmer waters (i.e., an oil spill off of Venezuela)?
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These processes would proceed more quickly in warm waters a. Warm water region is helpful because sun and higher temperatures help degrade the oil faster
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If there is a major oil spill in location ______, what area of the coastline should protection efforts initially focus on?
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Should protect entrances to water supply systems and opening to rivers and lakes
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If oil is released at depth, where will that oil be likely to go?
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Oil and water don't mix properly. This is called an emulsion: when two or more liquids are normally unmixable. Oil will rise and blob up in little patches all across the ocean. They form a surface slick. If the oil is in small droplets, it will rise so slowly that it will be effectively suspended in water
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We all hear and/or read scientific arguments on the web, on the radio, on tv, and/or from friends. How would you figure out if the argument was well-founded or not? How do you distinguish a poor scientific argument from a well-constructed scientific argument?
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Proof, hypothesis, trial and error make an argument well founded. A Poor argument if full of fallacies and opinions, while a good one contains a reasonable amount of facts.
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Explain how scientific revolutions can occur, using plate tectonics as an example. Why is plate tectonics now a theory instead of just being an idea or hypothesis?
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Scientific revolution happen when theories are repeatedly proven and backed. Scientific theories have been confirmed by repeated independent experimental tests.
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A Southwest Airlines plane recently had to make an emergency landing because a hole opened up in the roof! Why is this very dangerous?
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The air pressure is less with higher altitudes and less oxygen.
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What process causes your drink to become colder when you put ice cubes in it?
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Conduction (heat transfer by touch)
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Looking at a diagram of the distribution of temperature and salinity for water masses in the oceans, identify the water masses that have the highest and lowest temperatures.
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Warmest in east indies/indian ocean. Warmer near equator, colder near poles. Coldest in Antarctic.
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On a map, choose the regions that experience upwelling.
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Equatorial upwelling, coastal upwelling, upwelling in high latitude regions.
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You're a government advisor and are looking at some intelligence information that requires you to apply some of your knowledge from oceanography to a geopolitical scenario. The xxxx have decided to launch a long-distance missile from a base xxxx. If they aim it directly at the city, where will it land?
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It won't land on the city due to the coriolis effect and where the missile in launched matters. The northern hemisphere will puss it to the left and the southern will push it right.
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If Earth did not rotate, the prevailing surface winds would tend to blow across the US from:
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It would go north to south
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Look at the following diagram showing the changes in density with temperature in water. What do the different numbers point to?
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Density and temperature are inversely related in the ocean, with respect to only the temperature and density.
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An explanation of the cause and effect of a natural phenomenon that has been repeatedly confirmed by later experiments is:
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Scientific Theory
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On the basis of the scientific method, science supports the explanation of the natural world that:
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The ocean is slow to heat and slow to cool. Water's high ___________________ prevents extreme oceanic temperature variations, in turn affecting temperature ranges on coastal areas on land.
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Heat capacity
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The ocean is layered with respect to:
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The ocean is layered with respect to density
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Which of the following is true of scientific hypotheses?
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Must be testable, must be feasible
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After graduating from UCLA, your friend Nam joins Engineers Without Borders. His first assignment is to work on a freshwater well system in Iquitos, Peru, which is located at a latitude of 10° South. What is the direction of the prevailing winds in this region?
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Northwest
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Is sea ice being warmed through contact with the atmosphere or the ocean or both?
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Atmosphere
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Describe the sea ice-albedo feedback and how reductions in sea ice will affect climate over the next 20 years.
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With increasing temperature of the atmosphere more ice will melt which decreases albedo and therefore more heat is absorbed and creates a positive feedback
