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Midterm 3

Terms in this set (82)

Sources of external energy
SUN
describes vegetation, photosynthesis
sources of internal energy
volcanoes, geisers, etc.
Natural processes are driven by what?
different forms of energy
Hazards and
disasters result from processes that concentrate (accumulate. build up)
then release what?
energy
What are the different forms of energy?
thermal (heat), mechanical, gravitational,
electrical, chemical etc.
What is unique about the conversion of energy?
One form of energy can be converted into another
(eg. mechanical and thermal).
What forms of energy are the earth processes a result of?
largely result of interplay heat and gravity. Note
formation of solar system. Gravitational energy converted into heat.
What is internal energy?
sources of energy within the earth. Drives processes in
earth's interior. These processes impact the surface (earthquakes,
volcanic eruptions, mountain building (or orogenesis))
What is external energy?
sources of energy available to drive processes at the
surface. Includes solar energy and tidal energy. Essential to regulate
atmosphere and oceans, and hence climate and life
What is gravity?
an attraction between two objects with a force directly proportional to the product of their masses and inversely proportional to the square distance between them

the closer together = greater attraction and vice versa
What reflects gravitational attraction?
movement
What are tides caused by?
differences in gravitational pull from one part of Earth to another
What is the Sun's pull like on the earth?
Sun's pull in mostly uniform throughout Earth - small tides
What is the moon's pull like on the earth?
Moon's pull is much greater on facing side than on opposite side - tides are about twice the size of Sun's tides.
What do tides affect?
land, water and air - most obvious in ocean
What is buoyancy?
The downwards pull of gravity on an object immersed in a fluid experiences an upwards-directed force.
What powers hydrologic cycle and (with gravity) drives erosion - forms landscapes, causes landslides?
the sun - the principle source of energy at the earth's surface
What's the breakdown of the sun's energy that reaches the surface?
30% reflected back to space
47% absorbed as heat
23% evaporates water
What surface has a high albedo?
Snow and ice
What is the process of the hydrologic cycle?
Warm water evaporates; (moist) warm air rises; cools at altitude and precipitates water; cool (dry) air descends.
What is the balance in the hydrologic cycle?
Balance: Amount evaporated = amount precipitated
What are the 7 characteristics of water?
1. Close to its 'triple point'
2. Has a very large specific heat capacity
3. Has an extremely high latent heat of vaporization
4. Has an extremely high latent heat of melting
5. Bipolar molecule easily able to bond with other species
6. Highest surface tension of liquids
7. Expands 9% when frozen (most substances shrink) - therefore ice floats
what is latent heat?
Energy released on vaporization or melting
results from changing state
Water is incredibly efficient at what?
storing and transporting heat energy
What is the specific heat for water?
Specific heat of water = 4.2 kJ/kg, an unusually high value (the highest latent heat of any substance 2258)
example of the extraordinary properties of water
Energy required to raise the temperature of 1 kg of water from 0° C to 100° C = 420 kJ
Energy required to boil off that 1 kg of water = 2258 kJ
Boiling off the water takes > 5 times longer than getting the water to boiling point!
What is sensible heat?
Sensible heat is related to changes in temperature of a substance with no change in its phase.
measurable
What does the global ocean "conveyor belt" do?
The global oceanic "conveyor belt" (thermohaline circulation) transports and redistributes heat around the earth's surface. Driven by heat and density variations
what are some phenomenas driven by solar energy or triggered by storms?
tornadoes, hurricanes, flooding, heavy rains, wildfires
What percent of yearly deaths and damages does natural disasters cause?
75%
What is weather?
the day to day state of the atmosphere
combination of temp, humidity, precipitation, cloudiness, visibility, and wind
tornadoes, heat waves, hurricanes, floods
these things fluctuate quite rapidly and relatively short in length
What is climate?
looking at the average of what happens over a longer period of time
climate is more stable than weather over the years
ice ages, droughts, atmosphere changes, ocean circulation shifts
Most climate fatalities are due to what?
extreme heat or cold
What powers the weather?
solar radiation
What is insolation?
the intensity of solar radiation
Excess heat at equator is transferred through mid- latitudes to? how is it transferred?
polar regions
through air masses (wind) and ocean currents (water)
Equatorial belt (38oN to 38oS) faces Sun directly, so?
massive amounts of solar radiation are absorbed
Polar regions receive solar radiation at low angle, so?
much is reflected >> net cooling.
What are the ways in which heat can be transferred?
Conduction
Convection
Radiation
What is conduction?
heat energy moves through a material (typically a solid, like the poker)
What is convection?
heat energy moves with a material (typically a fluid, like air or water)
When air is heated it expands, making it less dense, so it rises. This is what drives convection
What is radiation?
heat energy is converted into electromagnetic waves, or radiation, which travels at the speed of light)
Hot air _______ and cold air _______?
rises, falls
relative to the surrounding air
Amount of water in the atmosphere depends largely on?
the temperature of air and this is related to pressure (height above the surface).
What is the troposphere?
Lowest layer of atmosphere 8 km at poles and 18 km at equator Warmer at base, colder above,
therefore unstable (warm air
rises and cold air sinks,
constant mixing leads to
weather)
What is the top of the troposphere called?
tropopause
What is the stratosphere?
Stable configuration of warmer air
above colder air
What is pressure?
Surface pressure is the force per unit area exerted by the weight of the overlying air
Air pressure tends to fall exponentially with?
increasing height
When the air is carrying as much water vapor as it possibly can, it is said to be?
saturated (reached water vapor capacity)
Warm air can carry more water vapor than?
cold air
What does the absolute humidity of an air mass refer to?
refers to the actual amount (mass) of water vapor per unit volume of the air.
What is it called when air is carrying as much water vapor as it possibly can?
saturated
What is relative humidity?
the humidity stated as a percentage of the saturation humidity of that same air mass
Rising warm air creates low pressure area
air flows (returns) to low pressure region across surface
Sinking cold air creates high
pressure area
air flows away
from high pressure region across
surface
Sinking cold air creates high pressure area
air flows away from high Pressure (in clockwise direction). Consistent with Coriolis effect.
Rising warm air creates low pressure area
air flows in toward low pressure (in counterclockwise direction). Counterintuitive - seems to contradict Coriolis effect!
what are fronts?
collision zone
Sloping surface separating air masses with different temperature and moisture content, can trigger severe weather, violent Storms
Cold front vs. Warm front
Cold front: cold air mass moves in and under warm air mass (tall clouds, thunderstorms). This effect occurs at the polar front (cold polar air flowing south forces warmer mid-latitude air to rapidly rise).
Warm front: warm air flows up and over cold air mass (widespread clouds)
Stages of a thunderstorm
1. early stage
2. mature stage
3. dissipating stage
what's the early stage of a thunderstorm?
requires continuous supply of rising, warm, moist air to keep
updraft and cloud mass growing. Surface winds pulled into low
pressure storm region
what's the mature stage of a thunderstorm?
Upper-level precipitation begins when ice crystals and water drops
become too heavy for updrafts to support Falling rain causes downdrafts, pulling cooler, dryer air into the storm Updrafts and downdrafts move side by side, creating gusty winds,
heavy rain, thunder and lightning, hail
what's the dissipating stage of a thunderstorm?
downdrafts drag in so much cool, dry air that the
updrafts necessary to fuel thunderstorm are cooled and cut off
What are the temperatures of lightning?
10,000-28,000 degrees C
or
18,000-50,000 degrees F

**Bolt of lightning 1.8-5 x hotter than surface of sun
What causes thunder?
Sudden increase in temperature of air around lightning bolt causes rapid expansion creating a shock wave similar to a sonic boom
What is the speed of lightning?
~110^8 m/sec (~100,000 km/sec, or 62,000 miles/sec). About 1/3 of speed of light (~ 310^8 m/sec, 300,000 km/sec, 186,000 miles/sec).

Could travel more than twice around the earth in 1 second
Hurricanes lessons fro history:
"I don't think anyone expected the breach of the levees"
this was six days after repeated warnings from experts about the scope of damage expected from Hurricane Katrina

not fair to say it was unexpected
Pre Katrina warnings from...?
Van Heerden
What are hurricanes?
large tropical ocean storms powered by the latent heat of water vapor
Requirements for the development of a hurricane?
1. Sea water at least 27 degrees
2. air must be warm and humid
3. must have weak upper level winds
4. Coriolis effect must be significant
What winds are considered a tropical storm?
63 km/hr
What winds are considered a hurricane?
119 km/hr
huge amounts of latent heat released by water vapor as air rises - much more than kinetic energy of the winds
the total power production associated with an avg hurricane is 200x that of global electrical power production
inside eye
cool, high-altitude air sinks and absorbs moisture
eye wall
cylinder shaped area of spiraling upward winds around eye strongest winds
Hurricane Origins
warm water currents at mid latitudes exert strong spatial controls of the birth and development of hurricanes (typhoons, cyclones)
Influences on hurricane paths:
a. if small or located to north, hurricanes missed coast lines
b. if strong, extensive, guides along east coast
c. if located south, guides hurricanes to gulf of Mexico
the Galveston Hurricane
september 1900
the drowning of an entire city
category 4
6000 drowned
hurricane camille
category 5
hurricane hugo
category 5
hurricane ike
category 2
wind damage and flooding and made it to ohio
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