Unit 5 Flashcards
energy
the capacity to do work.
– Work is done whenever matter
moves.
potential energy
• Energy of an object due to its position
kinetic energy
-Work needed to accelerate a given
body of mass from rest to a certain
velocity
thermal energy
Temperature/Heat
temperature
measure of kinetic energy – Molecules move in a random motion, and temperature is the speed of the molecules – Change in temperature makes gases, liquids, and solids expand and contract
different temperature scales
celsius scale, Kelvin scale, Fahrenheit scale
how to measure temperature?
-We use substances whose thermal properties are understood as a guide; thermometer or a ball thing (get from notes)
heat
• Depends on its volume, its
temperature, and its capacity to hold heat
gas (phase of water)
- A lot of molecular movement
* Molecules loosely bonded
liquid (phase of water)
- Not able to move as freely
* Molecules bonded
solid (phase of water)
- Not a lot of molecular movement
* Molecules tightly bonded
phase changes of water
– Freezing – Condensation – Deposition – Melting – Evaporation – Sublimation
warming processes
– Go from fast-moving molecules to slow, thus releasing heat
• Freezing
• Condensation
• Deposition
cooling processes
– Go from slow-moving molecules to fast, thus taking heat
• Melting
• Evaporation
• Sublimation
radiation (energy transfer)
– Transmission of energy from an object in the form of an electromagnetic wave
• Electromagnetic Spectrum
– Radiation is characterized (and sorted) by its wavelength and frequency
wavelength
– Crest to crest
– Unit is micron
• (1μm=10-6m)
frequency
– Number of waves
– Unit is hertz
• (cycles per second
shortwave radiation
radiation from the sun
longwave radiation
radiation emitted from the earth
conduction
– Energy transfer accomplished by
contact between molecules
– Only energy transferred
– Ex: Soil
convection
– Energy transfer through currents or
movements of fluid
– Both matter and energy transferred
– Ex: Boiling water
solar constant
– Intensity of the sunlight
• Around 1364 w/m^2
Average energy input at the top of the atmosphere is…
about 341 w/m^2
Absorption of solar radiation
– Energy striking a body is assimilated
by the body.
– When the energy is absorbed, the
temperature is raised.
reflected solar radiation
• The ability of an object to repel
radiation without altering the body or the radiation.
albedo
– Reflectivity of a surface
– Amount of energy reflected back into space by an object
– Albedo= (insolation
reflected/insolation received) x 100
scattering of solar radiation
• The process by which incoming solar
radiation is dispersed and produces a larger number of weaker rays, traveling in different directions.
Shorter waves are more easily
scattered than longer waves
• This explains why the sky is blue during the day and red at sunset!
transmitted solar radiation
– Waves pass completely through a medium without being altered • Depends on the opacity of the object • Also dependent upon wavelength of radiation
global energy balance
– On Earth there is a balance
• 100 Units of energy input from the Sun
• 100 Units of energy output from Earth
Incoming Solar Radiation
– 100 Units in • 33 Units reflected • 67 Units absorbed – Surface absorbs 45 but emits 15 – Atmosphere absorbs 22 and emits 52
net radiation
– Difference between emitted and absorbed radiation
- Earth has a net radiation of 0
– Solar energy absorbed equals solar energy reflected plus longwave radiation
emitted
vertical imbalance
– Surface surplus and atmospheric deficit?
• Surface
– Shortwave radiation exceeds longwave radiation
• Atmosphere
– Longwave radiation exceeds shortwave radiation
– Imbalance offset due to:
• Heat being transferred from surface to atmosphere (convective heat transfer)
• Evaporation and transpiration at surface (cooling surface)
• Condensation or “cloud formation” in atmosphere (warming atmosphere)
*Weather result of imbalance!
horizontal imbalance
– Tropical surplus and upper latitude deficit? • Tropical latitudes – Shortwave radiation exceeds longwave radiation • Middle and high latitudes – Longwave radiation exceed shortwave radiation – Imbalance offset through the motions of the oceans and atmosphere • Help distribute the heat throughout the latitudes *Weather result of Imbalance!
hydrosphere
– Powered by the sun • Evaporates water • Drives the ocean and atmospheric motions that carries water from place to place
water unique properties
1. Water is the only liquid found at Earth’s surface in large quantities 2. Water easily changes from one state to another 3. Solid phase (ice) is less dense than liquid phase 4. Water has a high specific heat
vapor pressure
– Measure of water vapor in the atmosphere
– Amount of pressure exerted by the molecules of water vapor in the
air
– Vapor pressure ranges from 0-4% of atmosphere (average 2%)
•If atmospheric pressure is 1000mb
– Vapor pressure is around 20mb (2%)
saturation vapor pressure
– Measure of maximum amount of water vapor the atmosphere can support at a given temperature
– Saturation vapor pressure increases
with temperature
• Warmer air has more energy to evaporate liquid water into water
vapor
humidity
– The amount of water vapor present in a column of air
relative humidity
-Percent of saturation ((e/es)x 100)
Negatives: temperature-dependent
-indicates how near the air is to saturation rather than the actual quantity of water vapor in the air.
-inverse relationship with temperature
absolute humidity
Mass of water vapor per volume of air – Positives: – Negatives: • Temperature-dependent – Daily cycle • Not user-friendly
specific humidity
Mass of water vapor per mass of air – Positives: • Not temperature-dependent – Negatives: • Not user-friendly
mixing ratio
Mass of water vapor per mass of dry air – Positives: • Not temperature dependent – Negatives: • Not user-friendly
dew point
Temperature at which saturation is reached – Positives: • User friendly • Not temperature dependent – Negatives: • Best measure of water vapor!
hygrometers
measure humidity; a sling psychrometer has two thermometers:– As the instrument is spun, evaporation occurs in the wet thermometer and the resulting temperature is lower (energy was lost) than the dry bulb temperature.
– The drier the air, the greater the cooling.
– The larger difference between wet-and dry-bulb temps, the lower the relative humidity.
surface water balance
– The measurement of inflow, outflow, and net annual surplus or deficit of water at a given location
•Water can be gained by precipitation
•Water lost by evapotranspiration or runoff
evapotranspiration
– Passage of moisture from the land surface to the atmosphere through the combined processes of evaporation and transpiration – Vegetated surfaces vs. open water surfaces
potential evapotranspiration
• The maximum amount of water that can be lost to the atmosphere from a
land surface when the availability of surface water is not a limiting factor
actual evapotranspiration
• The amount of water that is lost to the atmosphere from a land surface and can be less than the potential rate because of either soil moisture conditions or plant physiological controls
