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58 Cards in this Set

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  • Back
How much of earth is covered by water?
80%
Describe the water molecule.
-made of 3 atoms: two hydrogen and one oxygen
-v-shaped with hydrogen at one end and oxygen at the other
-oxygen is slightly negative and hydrogen is slightly positive
-opposite sides of opposite charges so water molecules attract
-when these sides attract they form hydrogen bonds
-each molecule can bond with four other molecules
-the bonds are weak
Describe heat capacity.
-the quantity of heat required to produce a unit change of temperature in the material
-it depends on the material's specific heat and the mass of the material
How much heat does it take to melt ice and vaporize water?
-0 C solid to a liquid at 0 C takes an addition of 80 calories for each gram of ice (latent heat of fusion)
-NO CHANGE IN TEMP.
-from water to vapor requires 540 calories of heat to convert 1 gram of water at 100 C to water vapor at 100 C (latent heat of vaporization)
How much does water compress?
-water has a low compressibility
-avg. pressure on ocean reduces the ocean's depth by about 37 m
-for every 10m of descent, the pressure increases by about 1 atmosphere
Why do tides exist on earth?
-caused by gravitational attractions from both the moon and the sun-the sun accounts for 1/3 and the moon 2/3 of tidal motion
Why are tides so complex?
-earth's rotation, ocean currents, land shapes and seafloor slopes all combine to alter tides at any given location
What are spring tides?
-moon is either new or full and gravitational forces reinforce one another so the tides have the greatest tidal range
What are neap tides?
-moon is in first or third quarter combined with the sun's tidal forces practically cancel each other out and the tides are lowest (or have the least range)
What are diurnal tides?
-one high and one low per day
What are semidurnal tides?
-two highs and two lows per day
What are mixed tides?
-a tide in which the high tides regularly reach different heights and the low tides drop regularly to different levels
What are gyres and what causes them?
-they are large, circular, wind-driven, oceanic flows
-caused by a complex interaction of wind speed and direction and distance across open water(fetch) as well as the coriolis affect which results from the earth's spin

-causes the current to be deflected in N. Hemisphere to the right and counterclockwise in the S. hemisphere
Describe upwelling.
-the upward flow of deep ocean water toward the surface

1. occurs principally along the west coast of africa, s. america, and the u.s.
2. principal cause: the surface flow along these shorelines are "deflected" offshore allowing deep water to rise
Why is upwelling considered good?
-nutrient rich water are brought to the surface creating a very rich food chain= fisheries
How are cold current deserts formed?
-the current is so cold that water does not evaporate out of it and the land nearby remains dry since there is no moisture in the air from the sea
How do you calculate water depths for waves to "feel" bottom and to "break"?
-"feel bottom" depth=wavelength/2
-"break"=wavelength/20

ex. wavelength of 100 ft. what depth does it break?
depth=100/20=5 ft
Define Tsunami.
-waves generated by events that cause significant subsurface displacement of water, such events including earthquakes, volcanic eruptions, underwater landslides and "turbidity" currents

-they are relatively harmless at sea but devastating when they make landfall

-large (20-50+ feet) tsunami waves inflict terrible damage in that they do not behave like normal breaking waves but flow inland almost like a flooding river

-means "harbor wave" in Japanese

-also known as seismic waves
-waves move fast and slow
-as they drag on the bottom friction slows the waves down, then the waves behind go upward cuz they are still traveling quickly
What are some of the recent tsunami tragedies?
-April 1, 1948 Hilo, Hawaii (waves refracted completely around the island
-July 1958 in Lituya Bay, Alaska (extreme wave height of 1720 ft)
-Sunda Tsunami in Indonesia on Dec. 26, 2004 (250,000+ death toll)
How are longshore currents generated?
-when the waves approach the shore at an angle which sets up a current in the surf zone that moves down the beach
Why do human settle along seashores?
1. moderate climate
2. plentiful food
3. exceptional transportation
4. opportunities for trade and commerce
5. plentiful recreational opportunities
6. aesthetic qualities of the seashore
Explain the continual between humans and the ocean.
1. natural disasters
2. natural processes of erosion and deposition that continually reshape coastlines and interfere with human societal activities

1. protect coastlines, structures, and waterways by armoring and replenishment
Describe groins.
-of rock and timber that are built perpendicular to the beach
-trap sand moving in the longshore transport which causes sand to build up on the up-current side and the loss of sand on the down-current side
what are jetties?
-very large groins constructed in pairs
-they protect bays and river mouths from "silting in"
What are breakwaters?
-structures that are used to protect and build beaches
-incoming waves break onto the structure but much of the sediment is carried over it and builds a beach leeward
-often the shoreline on either side of this artificial beach is eroded as wave energy is refracted and focused in those areas
What are seawalls (bulkheads)?
-structures that protect the shoreline behind them, but they focus wave energy, such that all or most of an original beach is removed
What is sand replenishment?
-sometimes an effective solution to beach erosion
-haul in sand from elsewhere
-sometimes pump it in from offshore sandbar
What do they use to prevent erosion if natural materials aren't available?
-use man-made materials such as concrete structures
Define spit.
-a beach area that extends outward from the main beach and then turns and parallels the shore
Define tombolo.
-a spit that extends offshore to an island
Define sea stacks.
-common features along the southern coast of australia
- caused by the natural erosion of headlands along the coastline. Typically, the ocean wears a hole through the headlands first, creating an arch which slowly expands over time as it erodes. Ultimately, the arch collapses, leaving a sea stack on one side and the headland on the other. Separated from the shoreline, the sea stack will slowly start to erode, ultimately melting away into the water or collapsing.
Define baymouth bars.
-a spit that completely closes access to a bay, thus sealing it off from the main body of water. These bars usually consist of accumulated gravel and sand carried by the current of longshore drift and deposited at a less turbulent part of the current. Thus, they most commonly occur across artificial bay and river entrances due to the loss of kinetic energy in the current after wave refraction.
What are the major gases in the atmosphere?
-78% nitrogen, 21% oxygen, 0.9% argon
-0.035% carbon dioxide
-water vapor ranging from 0.1% to 4.0%
What is the troposhere?
-sea level-10+km (6 miles)
-it is where the weather happens
-circulation by convection currents driven by the sun's energy, continually mix the air and ensure a homogenous composition
-avg. temp. range from 18 C near the surface to -40 C near the top
-decline in temp. is known as the negative time laps rate and equals about 6.5 degrees per km of height
What is the stratosphere?
-12-52 km
-ozone absorbs uv raising the temp. with increasing elevation
What is ozone?
-O3
-a form of oxygen that absorbs ultraviolet radiation from the sun
Describe sunlight.
-provides 98% fo the energy that drives earth's weather systems
-it comprises most of the radiation energy that reaches earth and "energizes" photosynthesis
Describe infrared radiation.
-warms the earth and atmosphere as it is partially absorbed by gases such as water vapor and carbon dioxide
-Heat rays
Describe ultraviolet radiation.
-has shorter wavelengths than visible light and is more energetic
-only small portion reaches earth's surface
What causes global warming?
-a natural phenomenon called the "greenhouse effect"
What would happen if there was no greenhouse warming?
-earth would be bleak, frozen world estimated at -5 degrees F
How does the greenhouse effect occur?
-certain gases allow visible light and a bit of UV and IR to warm the atmosphere and earth's surface, but do not allow much heat to escape from the atmosphere as it is re-radiated from the earth's surface as infrared radiation
What are the possible adverse effects of global warming?
-glaciers have retreated and sea level has risen several inches
What is the Kyoto Protocol?
-a legally binding agreement under which industrialized countries will reduce their collective emissions of greenhouse gases by 5.2% compared to the year 1990
-U.S. has not ratified nor withdrawn from it
What does the Kyoto Protocol and subsequent international agreements require regarding the production of carbon dioxide (now called a toxic substance by the EPA)?
-8% reduction for European Union
-7% for U.S.
-6% for Japan
-0% for Russia
-permitted increases of 8% for Australia and 10% for Iceland

-a signature of the protocol means that the nation is not bound by the conditions of the protocol but is willing to continue the treaty-making process and is obligated to refrain from acts that would defeat the object and the purpose of the treaty
How important are alternative sources of energy at the present time?
-very important if we want to cut down on CO2 emissions
In general what portion of our energy needs do alternative sources provide?
-not a significant portion of the world's energy requirements
-although nuclear and hydropower are most widely used
What are some problems with the presently held concept that humans cause global warming?
-evidence shows many warming and cooling cycles on earth that are natural in character and man was not burning fossil fuels millions of years ago
-prob caused by volcanic activity, wobbling of earth's spin axis, slight variations in earth's orbit and variations in the energy output of the sun
How are waves generated?
-WIND
-as the wind blows the friction between the air and the water stretches the surface, resulting in small wrinkles or ripples
-as the surface becomes rougher it is easier for the wind to grip the water surface and add more energy increasing the size of the waves
-as the waves get bigger the force returning the water to its level state is gravity and no longer surface tension
How do water molecules move as waves pass by?
-as wave energy moves through the open ocean, the water particles move in circular paths, but do not flow as a stream of water
How much of earth is covered by water?
-N hemishpere 61% water
-S hemishpere 81% water
How is the sun's energy earth's major climate moderator?
-water has such a high heat capacity and cuz the laten heat of vaporization is so large, large bodies of water act as heat "sinks"
Where does the salt in the oceans come from?
-erosion on land and volcanic eruptions
-ocean is not becoming saltier because salt is also being subtracted continually
What are the major salts in seawater?
-Sodium
-Chloride
-Magnesium
-Potassium
-Sulfate
-Calcium
What gives water its distinctive color?
-blue and green wavelengths of light that are more effectively transmitted and are reflected
-causes water to look blue-green
-red wavelengths are the longest so they are preferentially absorbed
What determines surface salinities in the ocean?
-result from the complex interactions between evaporation, precipitation, and mixing due to currents, wave action, and temperature...
Where are surface salinity the highest?
-restricted circulation environments like the Red Sea
-Polar areas where sea ice forms and leaves salt behind.
-between 20-40 degrees north and south where there is intense solar heating and low precipitation (evaporation > precipitation)
What causes ocean currents?
-(surface currents) wind driven phenomena that move very large volumes of water across the face of the planet and help moderate earth's climate
-(density) thermohaline circulation that is slow moving but moves enormous quantities of water beneath the ocean's surface