ATM OCN 100: Final Exam
438 Cards in this Set
| Front | Back |
|---|---|
|
Geostationary Satellites (Goes)
|
Stationary with respect to a fixed point on Earth's surface (revolves at the same rate as Earth)
-Far from earth (36,000 km) = coarse spatial resolution, but good temporal sampling.
|
|
Visible satellite
|
appears black where the sun is not hitting earth. See lots of black
|
|
Infrared satellite
|
shows a picture of the whole earth- also shows white around the whole earth. reads the surrounding temp of earth, so the universe is cold, shoing white.
|
|
Polar orbiting Satellites
|
orbit the earth from pole to pole
-Closer to earth= better spatial resolution, poorer temporal sampling
|
|
Surface- Station Model
|
are a simplified visual to illustrate the temp., wind direction, wind speed, pressure, pressure tendency, cloud over, dew point, current weather of a specific place.
*Study and know the symbols
|
|
90% of Earth's atmopshere (by mass) is below 16km (10 miles)
|
...
|
|
Weather
|
specific state of the atmopshere at given time/ place
|
|
Climate
|
accumulation or average of weather conditions over a long period of time
|
|
What is the atmosphere?
|
-a fluid
-a think layer surrounding the Earth
-Mainly a mixture of invisible gas with some solid liquid particles, that stays in place due to the force of gravity
|
|
the major permanent gasses are
|
Nitrogen -78%- source: bacterial denitriification during decay of biological material/ Sink: N-Fixation by lightning, fires or bacteria
Oxygen- 20%- Source= photosynthesis, Photolysis/ Sink= Oxidation, decomposition, respiration
Argon-.93%
|
|
Water in the Atm.
|
Greenhouse gas
Variable concentration
Invisible
|
|
Aerosols
|
particles suspended in air (dust, soot, salt)
-provide "nucleus" for cloud condensation nuclei or CCN)
-Can shade surface
|
|
How old is the universe?
|
10-20 Billion (13)
How do we know?
Expansion and the hubble constant
|
|
Earth's first Atm
|
lots of hydrogen
|
|
Earths 2nd ATM
|
Volcanism and bobmardment
lots of CO2
|
|
Earth's third Atm
|
Life
cyanobacteria
phosynthesis
|
|
Vertical Sounding
|
Measurement of how temps change with height in the atm
-weather balloons lift radiosondes into the air
actual temp is on the far right
dew point temp is on the far left
|
|
Lapse Rate
|
rate at which temp decrease with height
|
|
Temp inversion
|
vertical layer of the atm where temp increases with height
|
|
The Trophosphere
|
the layer of the Atm from the surface of earth to 10 miles above. Temp generally decreases with altitude. This is because the atm is nearly transparent to the suns energy and is instead heater from below by earth surface.
|
|
Stratosphere
|
layer above the trophosphere. the temp. increases with height here. this is because it is heated from above by the ozone layer!
|
|
Mesosphere
|
the third layer of the atm. generally temp decreases with altitude. this is because the air is heated from below by the ozone layer.
|
|
Thermo sphere
|
temperature is again heated with altitude by the atm.
|
|
Heat
|
is the total kinetic energy of a sample of a substance.
|
|
specific heat
|
amount of energy required to increase the temp of 1 gram of that substance 1 degree celcius.
|
|
conduction
|
is the process of heat transfer from molecule to molecule; requires contact. en example is when you touch something to feel if it is warm or cold. heat is transfered from the warmer object to the colder one.
|
|
convection
|
the process of transferring energy vertically. a heated parcel rises and the cooler air sinks to replace the warmer air.
|
|
temp advection
|
is the horizontal transport of energy in the atmosphere.
|
|
Latent heatingL changing phase of water.
|
is the heat absorbed or released per unit mass when water changes phase.
energy released to form ice is called the latent heat of fusion
energy increases to allow the vaporization of water is called the latent heat of vaporization.
energy released to form condensation is called…
|
|
radiative heat transfer
|
wavelength- is the distance between wave crests
amplitude is half the height from the peak of the crest to the lowest point in the wave.
shortwave radiation- UV, visible and near infrared radiation
longwave radiation- emitted by the earth, is less energeticand is characterized by…
|
|
the earth is farthest from the sun on?
|
July 4th. (aphelion)
|
|
the earth is closest to the sun on ?
|
january 4th, (perihelion)
|
|
if the sun is closer to the earth in january, why isnt it hot??
|
it is related to the tilt of the earth, not its distance.
|
|
solstices
|
at noon, the sun's rays strike the equator at the angle of 23 27. occurs on june 21st and dec. 21st
|
|
Equinox
|
occur when the sun's rays strike the equator at noon at an angle of 90 degrees. occur on March 20th and Sept. 22-23.
|
|
Zenith angle
|
is the angel at which the sun's energy strikes a particular location on the Earth. The angle is 0 degrees is the sun is directly over head and is 90 degrees on the horizon.
|
|
Atmospheric gases weakly emit and absorb energy in the 10-12 micrometer region. this is referred to as the infrared atmospheric window.
|
...
|
|
Density =
|
mass/ volume
|
|
Pressure=
|
Force/Area
|
|
What keeps air from falling to the ground?
|
Pressure change with height opposes weight of air
|
|
Energy
|
the ability to do work
|
|
potential wnergy
|
potential to do work
|
|
kinetic energy
|
energy of motion
|
|
internal energy
|
energy of molecular motion in a substance
-total energy produced by random motions of molecules and atoms
"energy of random jiggling
|
|
conservation of energy
|
energy cannot be created or destroyed, it can only change forms
|
|
temperature
|
measures the average kinetic energy of a molecule in a substance
|
|
heat capacity
|
amount of heat needed to raise the temp of an object 1 degree celcius
|
|
specific heat
|
amount of heat needed to raise 1 gram of an object 1 degree celcius
|
|
first law of thermodynamics
|
change in internal energy=
heat added to system-
work done by system
ex. why is the beach sand so hot on a sunny day, but the water stays comfortable?
same amount of heat added to both, so same change in internal energy but...
-Sun's energy absorbed in 1cm of sand
-small mass
…
|
|
why does temp decrease with altitude?
|
no heat added to the system
|
|
second law of thermodynamics
|
heat will transfer from a warm object to a cold object
|
|
conduction
|
heat transfer from molecule to molecule
conductivity: rate of heat transfer across an object
-katabatic winds: winds caused by cool air sinking down a slope
-air next to surface cools via conduction/ radiation
-cold/ dense air sinks down a slope
|
|
Convection
|
heat transfer via fluid motions (hot air rises, cold air sinks)
-buoyant plumes are called "thermals"
-if most buoyant air is already on top, convection does not occur.
|
|
Advection
|
heat transfer via horizontal fluid motion
|
|
latent heat
|
heat required for a substance to change phase
|
|
why does evaporation cool liquid water?
|
only most energetic molecules break free of attraction to other molecules
-remaining molecules are less energetic on average so temp decreases
|
|
latent heat: why is it important?
|
weather: condensation is a source of energy for rising air in clouds
-Climate: source of heat for higher latitudes
-source of heat for hurricanes
|
|
radiation
|
energy transfer by electro magnetic waves
|
|
temp cycles are all effected by
|
Latitude
surface type
elevation and aspect
Effects of Large Bodies of water
advection
cloud cover
|
|
Stefan-Boltzmann Law:
|
Hotter objects emit more radiation
|
|
Wien's Law:
|
Hotter objects= shorter wavelengths
Colder Objects= longer wavelengths
|
|
the sun radiates more energy with short wavelengths
|
...
|
|
the earth radiates more energy with long wavelengths
|
...
|
|
the fate of incoming solar radiation
|
Absorption- radiation is absorbed by molecule or particle in atmosphere or at the ground
Scattering- incoming radiation interacts with molecules or partiles in the atm and is sent in all directions
reflection- incoming radiation reflects back into space
|
|
albedo:
|
Fraction of radiation that gets reflected
-Bright (ice, now)= high albedo
-dark (wet dirt, water)= low albedo
|
|
radiative Equilibrium
|
balance between incoming shortwave and outgoing longwave radiation.
|
|
selective absorption
|
capability of greenhouse gases in the atmosphere to absorb and emit longwave radiation, but only at selected wavelengths.
the atmosphere is a selective absorber
|
|
The Greenhouse effect
|
-sun to earth
*shortwave radiation from the sun is transmitted through Earth's atmosphere and absorbed at the surface
-earth to atmosphere
*earth radiates energy to atmosphere
*aome passes through, but most is absorbed by the atm, warming the atm.
*also, energy is transferred to th…
|
|
selective absorbers in the atm
|
oxygen
oxone- 9-10 mircometers
carbon dioxide> 13 micrometers
Water Vapor- most important greenhouse gas: absorbs throughout the infrared range.
|
|
Anthropogenic GHG'
|
human generated
|
|
Anthropogenic Forcing
|
Emissions: rate at which a particular gas is being added to the atm.
Concentration: how much of that has is actually in our atm.
|
|
Natural Emissions +
Anthropogenic Emissions-
Natural sink=
change in concentration
|
...
|
|
is sources exceed sinks, concentration increases
|
...
|
|
sinks of CO2
|
Ocean- 20%- cold water absorbs more than warm water
Land- vegetation 20% but is limited as temp increases.
|
|
how do we know increase in co2 is due to antropogenic forcing?
|
carbon 14 and 13 are decreasingas carbon 12 is increasing. c 12 is found in fossil fuels
|
|
Why is the summer warmer than winter?
|
earth's orbit:
-distance to the sun
-angle of incidence
-length of Day
|
|
the Diurnal Cycle
|
imbalance in heating (radiation absorbed vs. radiation emeitted) leads change in internal energy (temp change)
-temp rises when energy gain exceeds energy loss
-temp drops when energy loss exceed energy gains
|
|
the diurnal cycle: clouds
|
daytime: reduce the amount of solar radiation reaching the surface
nighttime: reduce the amount of longwave radiation escaping
|
|
Water molecule
|
unique geometry gives rise to positive and negative polarity.
polarity= molecules are sticky
solid- least energy, molecules held together in crystal form (vibrate but dont move around)
liquid: molecules have more energy (they move around but still "sticky"
vapor: molecules ha…
|
|
Humidity
|
how much water vapor is in the air
|
|
how do we measure humidity?
|
-mixing ratio
-vapor pressure
-relative humidity
-dewpoint temp
|
|
mixing ratio
|
ratio of the mass of water vapor in a given volume of air to the mass of other molecules in that volume!
mass of h2O/ mass of dry air
-mixing ratio does not change if the temp chenges
-evaporation increases mixing ratio
-condensation decreases mixing ratio
|
|
vapor pressure
|
"partial" pressure exerted by only water vapor
1. water molecules start to evaporate
2. Water vapor exerts pressure on sides of container: vapor pressure
3. eventually rate of pressure= rate of condensation: saturation
|
|
Saturation
|
occurs when rate of evaporation equals rate of condensation.
|
|
saturation
|
mixing ratio: measures how much water vapor is actually in the air
Saturated mixing ratio: mixing ratio that air would have if it were saturated at its current temperature
Warm air= more energetic molecules=higher saturation mixing ratio
cold air= less energetic molecules= lower sa…
|
|
Relative humidity
|
ratio of actual water vapor in the air to the amount of water vapor required for saturation.
actual mixing ratio/ saturated mixing ratio
|
|
how do we change relative humidity?
|
1. change amount of h2O in the air
2. Change air temp.
|
|
Dew point temp
|
temp that air must cool to, to become saturated
|
|
Actual Mixing ratio
|
determined by Dew Point Temp
How to remember?
Q: ow do we determine how much water is actually in the air?
A. cool the air until condensation occurs, then measure its temperature.
this is the definition of dew point temp!
|
|
Saturated mixing ratio
|
determined by actual temp. temperature determines HOW MUCH WATER COULD BE IN AIR.
|
|
How do cloud droplets form?
|
we knwo that when the air is at 100% relative humidity, it is saturated. So..
-Cool the air to the dewpoint temp
-add water vapor until the air is saturated
-any further cooling, or water vapor added and vapor will start to condense= cloud droplets
|
|
problem with cloud condensation
|
its harder to condense onto a curved surface than onto a flat surface.
solution: some aerosols in the atm facilitate droplet formation
|
|
Aerosols:
|
small particles (dust, soot, sulpheric acid droplets, salt) suspended in the atm.
-water does not readily condense into drops on its own
-water does condense onto "hydroscopic aerosols".
|
|
continental aerosols:
|
-> 100, 000 per cm3; Anthropogenic 30% of all aerosols (60% in urban areas)
-crustal aerosols: erosion of earth's surface (dust storms, deserts)
-combustion and secondary aerosols: anthropogenic activites; primarily N. America, Europe, Asia
-Carbonaceous Aerosols: soot, biomass burnin…
|
|
Marine Aerosols
|
- 1,000 per cm3
-Salt (as bubble pop), Di-methyl Sulfide (DMS)
|
|
hydroscopic
|
water seeking- aerosols, salt
|
|
to find the saturated mixing ratio, first find the temperature and then on the mb graph, find the appropriate pressure and take the temperature and meet up with the pressure (ex. 850mb) it will give you the saturated mixing ratio, or the total possible amount of saturation possible
|
...
|
|
to find the actual mixing ratio, look for the dew point temp and go up from there on the pressure graph to find the actual mixing ratio!
|
...
|
|
after youve found the saturated and actual mixing ratios, make sure you divide the actual by the saturated to get the relative humidity.
|
...
|
|
types of fog
|
...
|
|
radiation fog
|
cooling on clear nights
-light winds required
-common in valleys
|
|
advection fog
|
as warm air is advected over a cold surface, it cools to the dewpoint temp.
|
|
evaporation/steam/mixing fog
|
form when water evaporates into the air, eventually saturating the air.
-can occur with rainfall- associated with inversions and warm fronts
-also when cold air flows over a warm lake (steam fog)
ex. breath
|
|
upslope fog
|
rising air cools to saturation
|
|
lifting mechanisms that form clouds
|
-most clouds form when air cools to the dew point as a parcel or air rises vertically as an updraft
|
|
lifting condensation level (cloud base)
|
as unsaturated air rises, it cools to 10 degrees C/ km. the dewpoint temp cools at 2deg.C/km. Eventually the actual air temp catches up to the dew point: any further rising and condensation will occur.
|
|
Ways that air can be forced upwards
|
...
|
|
orographic lifting
|
air flows up over a mountain
|
|
frontal lifting
|
when less dense warm air is forced to rise over a cooler, denser air
|
|
convection
|
air near the surface warms and rises
|
|
convergence
|
when air near the ground converges, or is squeezed together, and rises
|
|
dry adiabatic lapse rate
|
10 deg C/ 1000m
|
|
adiabatic means no heat is added/ removed from the parcel
|
...
|
|
Dry adiabatic
|
no heat is exchanged with the environment, no condensation- only work is done
|
|
moise adiabatic lapse rate
|
6deg.C/1000m
no heat is exchanged with environment- work is done and latent heat is released. latend heat adds 4 deg C per km
|
|
Dry adiabatic lapse rate: 10degC per 1000m
Moist adiabatic lapse rate:
6degC per 1000m
|
...
|
|
Clouds
|
1. High clouds
-Cirrus
-Cirrostratus
-Cirrocumulus
2. Middle clouds
-Altostratus
-altocumulus
3. Low Clouds
-Stratus
-Stratocumulus
-Nimbostratus
4. Clouds with vertical development
-Cumulus
-Cumulonimbus
|
|
Stratus
|
life fog fovering above the ground
|
|
Nimbostratus
|
precipitating stratus
|
|
stratocumulus
|
low-lying cloud combining layered and convective cloud types
|
|
cumulus
|
flat bases and intricately contoured domed tops
-fair weather cumulus
-cumulus congestus- tall relative to their width
-can produce brief heavy rain for a short time
|
|
Middle clouds
|
...
|
|
altostratus
|
layered clouds made up mostly of water droplets
|
|
altocumulus
|
similar to stratocumulus with a higher base
|
|
High clouds
|
...
|
|
cirrocumulus
|
similar to altocumulus but made of ice and have smaller elements
|
|
cirrostratus
|
layerlike, uniform, made of ice
|
|
Cirrus
|
wispy, fibrous clouds made of ice
|
|
cumulonimbus
|
thunderstorm clouds
-extent to high altitutes
-produce large amounts of precipitation
-flattened anvil shape of the top of the cloud
-under the anvil, sinking air may create pouches called mammatus
|
|
how does precipitation form?
|
...
|
|
condensation
|
air cools to dew point, condenses into drops
problem: saturated vapor pressure for flat surface is less than for a curved surface.
=very difficult for "more curvy" small drops to grow than big drops
problem:
requires relative humidity>>100% (tough to achieve) As drops grow, mo…
|
|
termial velocity
|
occurs when gravitational force equals force due to air resistance
|
|
air resistance
|
slows rate at which drops fall
-proportional to velocity times surface area
|
|
gravitational force
|
-causes rain drop to fall
-proportional to mass
|
|
terminal velocity is proportional to the size of the raindrop
|
...
|
|
larger drops overtake smaller drops
|
...
|
|
large drops frow by colliding with smaller drops; coalescence
|
...
|
|
thin clouds, weak updrafts: small drops form, may produce drizzle.
|
...
|
|
Thick clouds, strong updrafts: large drops form may produce heavy rain
|
...
|
|
bergeron Process
|
cloud droplets: dont spontaneously freeze at subzero temps, until about -40 deg C.
Ice Nuclei- Lattice structure similar to ice (makes it easier for deposition, or for instantaneous freezing) Much less common than CCN
So.. many more liquid cloud droplets than ice crystals in non-gl…
|
|
Bergeron Process: Key
|
saturated mixing ratio for liquid water drops is greater than that for ice
-ice particle that happens to be next to a liquid water droplet....
-air is saturated for the liquid water droplet
-air is super-saturated for the ice particle
=ice particle grows
*liquid water droplet an…
|
|
Growth of ice/ snow crystals
|
...
|
|
accretion
|
crystals grow as supercooled drops instantly freeze. forms "graupel"
|
|
aggregation
|
falling crystals stick together, form snowflakes
|
|
Buoyancy can be thought of as the ability to float
|
...
|
|
positively buoyant
|
object floats
|
|
negatively buoyant
|
object sinks
|
|
floating/sinking depends on whether the object has less/ more mass than an equal volume of fluid that gets displaced
|
...
|
|
if the mass of the log is less than the mass of the displaced water, then the log will float
|
...
|
|
if the mass of the log is greater than the mass of the displaced water, then the log will sink.
|
...
|
|
if a parcel of air is less than the environment then the parcel is positively buoyant
-if a parcel of air is equal to the environment, then the parcel is neutrally buoyant
-if the parcel is greater than the environment, then the parcel is negatively buoyant
|
...
|
|
we can describe buoyancy in terms of comparing temps.=
|
Tparcel>Tenv= positively buoyant (rises)
Tparcel=Tenv= Neutral (doesnt move)
Tparcel<Tenv= negativelt buoyant (sinks)
|
|
stability: a measure of the likelihood that a physical system will remain unchanged after it is perturbed.
|
...
|
|
Stability of the atm.
|
refers to the likelihood that a parcel will:
-return to its origin (stable)
-accelerate away fom its origin (unstable)
-be at equilibrium with its environment (neutral)
as compared to its environment.
|
|
key to stability of the atm.
|
compare a parcels temp with the temp of the environment into which it is lifted.
|
|
Absolutely stable
|
suppose the environmental lapse rate is 4 deg C per 1000m- if the parcel is unsaturated then as it is lifted, it will be colder than its surroundings.
if the parcel is saturated, then as it is lifted, it will also be colder than its surroundings.
Environmental Lapse rate is less than…
|
|
absolutely unstable
|
absolutely unstable imagine the envornmental lapse rate is 12deg C per 1000m= if the parcel is unsaturated than as it is lifted, it will be warmer than its surroundings.
if the parcel is saturated then as it is lifted, it will also be warmer than its surroundings.
the Environmental …
|
|
Conditionally stable
|
Suppose the envronmental lapse rate is 8deg C/ 1000m: if the parcel is unsaturated then as it is lifted, it will be colder than its surroundings.
if it is saturated, as it is lifted, it will be warmer than its surroundings.
A conditionally unstable environmental lapse rate lies betw…
|
|
Stable
|
few clouds, light cumulus humilus, clear skies
-often no level of free convection (LFC)
|
|
Shallow to moderate deep lay of uconditional instability
|
-Cumulus congestus, patchy clouds, sometimes breezy.
|
|
deep layer of conditional instability
|
-Cumulonimbus, thunderstorms posible, possible severe weather.
|
|
Single cell thunderstorm lifecycle
|
3 stages
-Cumulus- parcels ascent in the updraft and get saturated at the lifting condensation level, LCL, or cloudbase
-Mature- begins when precipitation starts to fall
*time of most lightning, rain, small hail
*a downdraft develops with cooling due to evaporating precipitation
…
|
|
lifting condensation level LCL
|
as a parcel of air rises, it cools. The LCL or cloud base occurs where the actual and dewpoint temp of that parcel are equal. After the air parcel reaches the LCL at 1km, it is saturated. Now it cools at the mosit adiabatic lapse rate of 6 degC/1000m
When a parcel's temp becomes warmer…
|
|
Cloud Top
|
above 6km, the moist adiabatic lapse rate is closer to 8deg C/ km. Parcel continues to cool as it rises, and eventually becomes colder than the environment. and the parcel stops rising. the level at which a parcel becomes cooler than its surroundings.
|
|
lifted index
|
a way to describe stability with one number
-is a difference in temp at 500mb
-the parcel temp is determined by raising a surface parcel to saturation at the DALR and to 500mb at the MALR
-negative values are unstable.
|
|
how can a thunderstorm grow in intensity?
|
need to cancel the shutoff mechanism for a single-cell thunderstorm
-get rid of evaporation (saturated environment)
-this sometimes occurs in hurican genesis
-move the precipitation away from the updraft by vertical winds shear! (multicell, squall lines, supercells
|
|
Vertical wind shear
|
-more severe thunderstorms develop when there is vertical shear of the horizontal wind
-the westerly (west to eat) part of the wind increasing as height increases
-clockwise tirning of the direction from which the wind blows as height increases
*forexample, southerlies at the surface…
|
|
Multicell thunderstorms
|
composed of several individual single-cell storms, each one at a different stage of development
- can last several hours
-can produce severe weather (high winds, hail)
-moderate amount of vertical wind shear
-wind shear moves downdraft away from updraft
-new cells originate along gu…
|
|
Supercell thunderstorms
|
the supercell thunderstorm is a large single cell storm, sometimes 32km or more across, that almost always produces dangerous weather.
-strong wind gusts, large hail, dangerous lightning and tornadoes
-require a very unstable atmosphere
-requires strong wind shear.
|
|
Microbursts
|
develops when rain falling from a thunderstorm evaporates underneath the cloud, cooling the air beneath
-cold heavy air plunges to the surface and splashes against the ground
-air then rushes sideways and swirls upward as a result of the pressure gradient between the cold air and the wa…
|
|
Tornadoes
|
-are rapidly rotating columns or funnels of high wind that spiral around very narrow regions of low pressure beneath a thinderstorm.
-visible because of condensation, dust and debris
-if the circulation does not reach ground, it is called a funnel cloud
usually less than 1.6 km across
|
|
Velocity
|
magnitude and direction of motion
|
|
speed
|
magnitude of the velocity
|
|
direction
|
...
|
|
acceleration
|
change in velocity- can be a change in speed and or direction!
|
|
newtons second law
|
a force acting on an object causes the object to accelerate
|
|
netforce is the sum of all forces acting on an object
|
...
|
|
vertical forces
|
...
|
|
gravity
|
mass times grvitational acceleration
-always directed downward
|
|
friction
|
acts opposite to direction of motion
-strength is proportional to speed
|
|
pressure gradient force
|
change in pressure over a distance
-always directed toward lower pressure
|
|
terminal velocuty
|
velocity at which the frictional force exactly balances the gravitational force.
|
|
hydrostatic balance
|
gravitational force balances presure gradient force, net force= zero
|
|
what keeps air from falling to the ground?
|
hydrostatic balance: change in pressure with height opposes weight of air.
|
|
how can we compare horizontal changes in pressure?
|
convert pressure measurement to a common elevation: sea level
|
|
pressure changes much more rapidly in the vertical than the horizontal direction.
|
...
|
|
Upper Level height Maps
|
...
|
|
trough
|
elongated region of low heights
|
|
Ridge
|
elongated region of high heights
|
|
winds:tend to blow parallel to lines of constant height
|
...
|
|
Joplin tornado
|
On may 22, 2011
-atmosphere was:
-very unstable
-had winds turning clockwise w/height (veering)
-was very moist at the surface
-had a dry line feature as a vertical forcing mechanism
it boils down to the moisture:
helps in getting strong up drafts
-helps set up a dry line fo…
|
|
Pressure Gradient Force
|
-the force that results from pressure differences over distances in a fluid
-PGF always directed from high to low pressure
PGF= Pressure Change/ distance
PGF is higher where isobars are closely spaced
|
|
Friction
|
resistance when one object is in contact with another object
-opposes forward motion (slows wind)
-is important only near the Earth's surface
-the friction force is stronger over rough surfaces and/ or when the wind is strong
|
|
Apparent forces
|
Consider: were standing in a subway car with a Tefllon floor. What happens as the car accelerates?
-As car accelerates, it looks like we slide backwards, BUT were actually still and our reference frame is accelerating.
-From perspective of the car, it is apparent that a force is pushing…
|
|
Coriolis Force
|
Apparent force that exists because we live on a rotating reference frame.
-deflects the wind to the RIGHT in the Northern hemisphere.
-Deflects wind to the LEFT in the Southern hemisphere!
-is strongest at the poles and zero at the equator
-is stronger for stronger winds and weaker f…
|
|
Relevant forces for air movement
|
1. Winds above 1km:
-Pressure gradient Force
-coriolis force
-no friction
2. Winds near the surface:
-pressure gradient force
-coriolis force
-friction
|
|
Pressure Gradient force points toward lower pressure perpendicular to isobars
|
...
|
|
If Coriolis force is balancing PFG, it must have equal magnitude, but opposite direction!
|
...
|
|
Air aloftL friction nearly zero so balance is between PFG and COR
^ PGF
-------->Wind
v Coriolis
Wind:Coriolis force always acts to the right of the wind and at right angles! in the northern hemisphere
Wind must be parallel to isobars!
|
...
|
|
Air spirals counter clockwise around a low
|
...
|
|
Air spirals clockwise around a high
|
...
|
|
Cyclonic
|
counter clockwise motion or Low
Netforce must be inward, which means: PGF>CF
|
|
Anticyclonic
|
clockwise motion
netforce must be inward which means CF>PGF
|
|
for the same pressure distribution, winds move slower around a low than a high
|
...
|
|
Surface Winds
|
...
|
|
Consider a wind in geostrophic balance, that is suddenly acted upon by friction:
-friction causes wind to slow down
*Slower wind reduces the Coriolis force, so theres a net force pushing the wind to the left of geostrophy
*New wind direction sets up new CF and frictional direction…
|
...
|
|
How to label Surface Lows on a surface level map
|
1. identify the Pressure gradient force~ remember that PGF lies across the isobars, from a high to low direction.
2. Label Coriolis anf Frictional forces~ Coriolis forces always are toward the right in the northern hemisphere. Friction is the opposite direction of the winds. Cor and Fr…
|
|
be able to label both an aloft PGF, Wind directions and CF and a surface wind map of PGF, W, FF, and CF
|
...
|
|
Convergence
|
the piling up of air/ fluid
-Wind converges into low pressure
|
|
Divergence
|
the spreading out of air/fluid
Wind diverges away from high pressure
|
|
troughs: are cyclonic, spin counter clockwise and are located in lows
|
...
|
|
Ridges: are anticyclonic, spin clockwise and are located in highs.
|
...
|
|
In a low surface pressure, moist air rises
|
...
|
|
in a high surface pressure, dry air sinks
|
...
|
|
jet streams
|
thin rivers of air with winds exceeding 100 km found at 10-15 km elevation
|
|
The thermal wind
|
a horizontal change in temp causes wind speed to increase with height.
|
|
Why do we find wind speed maxima near the trophopause?
|
1. Horizontal temp difference implies pressure decreases more rapidly in cold air than warm air.
2. The pressure gradient then, increases with height
3. An increased pressure gradient implies increased wind speed.
|
|
Larger temp difference= larger pressure difference=wind speed increases even more
|
...
|
|
Why are winds aloft strongest where horizontal temp changes are largest? and why are winds strongest near the trophopause?
|
- the thermal wind relates temp and winds to each other.
-the winds are more westerly as you go up wherever its colder toward the poles.
|
|
thermal circulation
|
consider
1. flat isobar surfaces over some distance
2. air starts to cool: upper level isobaric surfaces fall, pressure gradient develops at upper levels
3. as mass converges aloft, high pressure develops at the surface. As mass diverges aloft, low pressure develops at surface
|
|
Land/ Sea Breezes
|
...
|
|
Daytime
|
land heats up, air over water stays cool. produces sea breeze (breeze from sea) sea breeze occurs during day times....We see the difference because the land is quick to heat and water is slow to heat.
|
|
Nighttime
|
land cools, air stays warmer over the sea and produces land breezes, breeze from the land. Occurs at night.
we see this because the land is quick to cool and water is slow to cool.
|
|
The sea breeze
|
is a daytime circulation
- has the warmer, rising air column over the land, which absorbs more incoming solar radiation
-has the cooler, sinking air over the water, which absorbs less radiation.
-air flows from warmer to cooler column aloft
-air flows from cooler to warmer column…
|
|
the Land breeze
|
s a nighttime circulation
-has the warmer, rising air column over the water, which holds radiation.
-has the cooler, sinking air over the land which lost warm solar radiation from during the day.
|
|
Monsoons
|
monsoons are weather features driven by seasonal differences in the heating of land and ocean.
occurs near Arabian Sea and Bay of bengal
|
|
The general circulation
|
what conditions (wind, pressure, precipitation, temp) look like if we average over long periods of time and over large areas.
|
|
three cell model of the atm
|
At the equator there is a Hadley cell, second is ferrel cell and last the polar cell.
|
|
air mass:
|
a large body of air whose properties of temp and moisture content (humidity) are similar in any horizontal direction.
-source regions have similar characteristics
-light winds
- uniform surface over a large region
-not coastline
-Air masses can move away from their source regions
|
|
Air masses by temp
|
Polar (P): formed poleward of 60deg: cool or cols
Arctic (A): formed over actic: very cold
Tropical (T): formed within about 30deg of the equator- hot or warm
|
|
Air masses by moisture content
|
Continental (c): formed over large land masses: dry
Maritime (m): formed over the oceans: moist
|
|
Lake effect snow
|
cP air (cold and dry) blows over relatively warm water
-Air gains moisture/ heat= more buoyant near surface= unstable
-downstream, clouds and snow (hills and convergence on leeward side help with lifting)
example is wind blowing from wisconsin over lake michigan to michigan.
|
|
mT: Marine Tropical
|
warm, moist air from tropical regions. Pacific (Hawaii), Gulf of Mexico
midwest: low pressure stalls over central/ western U.S.= warm moist flow from Gulf= warm, humid conditions
|
|
Front
|
transition zone between two air masses of different densities, usually due to temp differences
|
|
cold front
|
denoted by blue line with triangles pointing in direction of movement
-cold, dry air is replacing relatively warm, moist air
-sharp temp gradient across front
-chages in moisture contenct (dewpoint)
-wind shift/ pressure minimum
-clouds and precipitation
|
|
warm front
|
denoted by red lines with semi circles pointing in direction of movement.
warm moist air is overriding more stationary, cold dry air
|
|
occluded fronts
|
denoted by purple line with alternating triangles and semicircles pointing in direction of movement. is where the coldfront catches up with the warm front
|
|
Mid latitude Cyclones: extra-tropical cyclones
|
weather phenomenon characterized by surface low, 1000-2000km horizontal scale, warm/ cold fronts, and associated weather
1. Begin as a disturbance, some times on a stationary front
2. Develop into "open wave"
3. intensify, begin to occlude (maximim intensity)
4. dissipates after o…
|
|
cyclogenesis
|
cycle of cyclone birth and growth
Key ingredients:
-surface temp gradients, a front
-a strong jet stream, helps the low deepen and the fronts intensify
-presence of mountains or other surface boundaries like a coastline near a warm ovean current
-winds blowing across temp gradients…
|
|
How do cyclones strengthen?
|
-Temp advection:
*Cold advection under an upper level trough causes the trough to intensift
*Warm advection under an upper level ridge causes the ridge to intensify
-Upper level divergence/ convergence:
*Divergence above a surface low causes the low to deepen
*convergence above a s…
|
|
Temperature Advection
|
ConsiderL a situation where isotherms (lines of constant temp) cross lines of constant height. Then: winds cross isotherms
|
|
Warmadvection
|
winds blow from warm to cold region
|
|
cold advection
|
winds blow from cold to warm region
|
|
Temp Advection
|
Consider: Isptherms are parallel to lines of constant height. Then winds to not cross isotherms.
No Temp Advection
|
|
Temp. Advection
|
Surface: cold advection: occurs behind cold front
warm advection: occurs ahead of warm front
|
|
Upper and lower level
|
considered upper level trough that sits to the west of a surface low
A. Cold advection-
*occurs beneath trough
-column of air cools
-upper level heights fall
-trough deepens
B. Warm Advection-
*occurs downstream of trough.
-column of air warms
-upper level heights rise
-do…
|
|
Total Effect of this^
|
Cold advection beneath trough= trough intensifies
Warm advection downstream of trough= ridge develops
Net Effect: trough curvature increases
|
|
cyclogenesis
|
"vertically stacked cyclone: low pressure aloft is directly above low pressure at the surface
|
|
What if air aloft is diverging over a low?
|
divergence aloft, above a low=
-loss of mass
-low presssure deepens
|
|
what causes air aloft to diverge?
|
A. upstream of trough: flow is in geostratic balance- PGF and CF balance.
B. Middle of Trough Axis
C. Downstream of trough
A to B= (upstream of the trough) air is piling up or convergins
B to C=(downstream of the trough): air is spreading out or diverging.
Air tends to CONVER…
|
|
Cyclogenesis and Veritcal Structure
|
Consider:
-an upper level trough that is situated to the west( upstream of a surface low:
=divergence above aloft surface low
=convergence aloft above surface high
if divergence aloft is greater than surface convergence then= loss of mass, low intensifies.
If convergence aloft…
|
|
Aloft Map= 500mb or greater
|
...
|
|
surface map = surface or 0mb
|
...
|
|
Vorticity
|
spin of air around its vertical axis
- right hand rule: curve finger inward toward palm in the direction that the fluid is moving.
|
|
Positive Vorticity
|
thumb wil point out of the page (upward)
|
|
negative Vorticity:
|
thumb will point into the page (downward)
|
|
How does Vorticity change?
|
stretching: increases relative vorticity
squashing: decreases relative vorticity
|
|
lee Cyclogenesis (colorado Lows)
|
Consider: a column of air moving over a mountain range:
A. Initial cyclone
B. Vortex squashing= cyclone weakens over mountains
C. Vortex stretching= cyclone redevelops in lee of mountains.
|
|
relative vorticity
|
spin of air relative to earth
|
|
planetary vorticity:
|
spin of air due to earth's spin (depends on how earth's spin projects into the local vertical direction)
|
|
Optics
|
...
|
|
the "normal" is the the direction perpendicular to the surface
|
...
|
|
What can happen to light in Earth's atmopshere?
|
...
|
|
Reflection
|
the incident angle with the "normal" equals the outgoing angle
|
|
Refraction
|
Light slows as it enters a medium of a greater density and speeds as it enters a medium of lesser density.
-light bends toward the normal as it enters a more dense medium.
|
|
Refraction and Dispersion
|
Refraction causes some wavelengths to bend more than others: Blue bends more than red light.
|
|
Scattering
|
incoming light gets sent in all directions
|
|
Why is the sky blue?
|
Rayleigh scattering
|
|
Why is the ocean blue?
|
Reflection of sky!
|
|
Why are sunsets red/orange?
|
near the horizon, light travels through more atmosphere than when directly over head, so more blue light is scattered away.
|
|
Crepuscular Rays
|
Light is "equally scattered" by large particles
|
|
Mirages: Refraction
|
As light rays enter a more dense medium (the atm), they bend towards the normal. This makses stars and the sun appear higher in the sky than they are.
|
|
Sunrise/Sunset occur about 2 minutes before/ after than the sun actually passes above/below the horizon.
|
...
|
|
Mirage
|
inferior imageL light enters a less dense medium (very warm air near surface)
|
|
Halos and Sundogs:Refraction
|
Halos occur when Light refracts through COLUMNAR ice crystals high in the atm.
sundogs occur when light refracts through HEXAGONAL ice crystals high in earth's atm.
|
|
Rainbows:Refraction and reflection
|
rainbows occur when sunlight enters a raindrop and the light bends an reflects off the back of the raindrop. Colors are seperated by dispersion.
-rainbows are at the apex of a 42 degree anfgle between you and the sun.
-rainbows cannot be seen when the sun is higer than 42 deg from the h…
|
|
secondary rainbows
|
occur when there is a double internal reflection
-secondary rainbows make a 52 deg angle and are reversed.. blue on top, red on bottom.
|
|
why dont winds just keep getting faster as air moves poleward?
|
jetstream becomes unstable= starts getting wavy
wavy== Mid latitude cyclones
|
|
strong temp difference between tropics and high latitudes= strong Jet stream
|
...
|
|
if wind speed in the jet is due to temp contrast, what season would experience the strongest jet?
|
winter. due to extreme cold and warm contrast.
|
|
Ocean Circulation
|
...
|
|
Thermohaline Circulation
|
water sinks in the North Atlantic and Antarctic, fills the deep ocean around the globe. Returns to surface in india, Pacific and Southern Oceans and returns to the Atlantic.
Thermo: warm water loses heat as it moves north in the atlantic
Haline: evaporation causes water to become mo…
|
|
The poleward transport of energy
|
-without this transport of energy the poles would be much colder and the tropics much warmer.
-poleward energy transport is accomplished by both the atmosphere and the oceans.
-The region of maximum energy transport lies between latitudes 30 deg and 60 deg.
Net effect: cyclones tr…
|
|
Tropical Pacific Mean State
|
Tropical Pacific Mean State Key Features:
1. Easterly Winds
2. Thermocline close to surface in East
3. Colder Water in east- cold tongue
4. Warmer water in the west- warm pool
5. rainfall in West
|
|
thermocline
|
large vertical temperature difference that separates warm surface water from colder, denser sub-surface water.
Thermocline slopes upward towards the east- south america
|
|
Tropical pacific normal conditions
|
easterly trades cause thermocline to deepen in the west, shoal in the east.
Warm water "piles up" in the West
|
|
hadley circulation+ Coriolis force= easterly trade winds
|
Warm in western pacific
cold tongue in Eastern pacific
|
|
Force Balance for water in the equatorial Pacific:
|
-wind pushes water westward (wind stress)
-coriolis force balances the wind stress
-water DIVERGES at the equator
^
I Ocean current
I
Wind Stress<--------------->CF Equator-------- Divergence-------
Windstress<---------------->CF
I
I Ocean Current
V
|
|
Why is there a cold tongue?
|
-divergence: causes "upwelling" at the equator
-upwelling brings COLD water to surface in the eastern pacific
|
|
tropical Pacific normal conditions
|
-easterly trades cause thermocline to deepen in the west, shoal in the east
-winds also cause upwelling along the equator, bringing cooler subsurface water to the surface
-cooling from upwelling is most pronounced in the east, where the thermocline is close to the surface.
|
|
ElNino
|
Anomalous warming of the ocean surface in the central and eastern equatorial pacific.
|
|
southern oscillation
|
oscilation in mass between the eastern pacific and the western pacific and indian oceans
|
|
El Nino
|
termed in 18881 by Dr Luis Carrenza
- named el nino (the christ chile because it has been observed to appear immediately after Christmas
|
|
Sir Gilber Walker identified the Southern Oscillation in 1923
"when pressure is high in the pacific ocean it tends to be low inthe indian ocean from africa to australia
|
...
|
|
Past climate changes: How do we know what happened?
|
"proxy data" indirect info that tells us about climactic conditions in the past.
|
|
the past 100ma
|
...
|
|
ocean sediments
|
1. rainfall and runoff transport sediments to the ocean, where it is depositied on the sea floor in layers
2. Bioloical Activity: plankton dies, falls to ocean floor and accumulates
3. sediment cores archive past climactic info (e.g. shells, chemical composition of sediment, thickness…
|
|
the past 500 Ka
|
-ice cores tell us about climate over last 500 ka
-oxygen isotopes, Bubbles (CO2, others, dust)
|
|
the last 1000yr
|
-proxy data from many sources
-tropical glaciers wont be around much longer
-tree rings (tells us about temp and precipitation variations- annual resolution)
-fossil corals and Speleotherms: annual accumulation= temp, precipitation
|
|
Oxygen Isotopes as a Temp Proxy
|
-oxygen atom typically has 8 protons and 8 neutrons. One in about 400 oxygen atons have 10 neutrons
-O18 is heavier than O16 so it gets left behind when ocean water evaporates
-ice sheets have relatively low amounts of O18 and sea water has relatively high O18
- the O18/O16 ratio tells…
|
|
consider a cold climate with large ice sheets
|
-lots of H2O locked up in ice sheets (ice is low in O18= more O16 is trapped in ice sheets
-O18 in ocean is relatively large
Cold climate:
-less O18 evaporates, more O18 rains out before reaching ice sheets
=O18 in ice is relatively low
|
|
consider a Warm climate with small ice sheets
|
-less O16 locked up in ice sheets =O18 in ocean is relatively low
Warm climate:
-more O18 evaporates, less O18 rains out before reaching ice sheets=O18 in Ice is relatively high.
|
|
Summary: We can determine temperature based on the ration of O18 to O16
Cold Conditions: less O18 evaporates so O18 ratio is:
LARGE in water (ocean sediment core): more O16 is trapped in ice sheets
SMALL in ice sheets: lessO18 evaporates to eventually snow onto glaciers
Warm Con…
|
...
|
|
The past 100 Ma
|
-ocean sediment cores shows cooling temps over the last 30 Ma, epecially over the last 3 Ma
|
|
The past 3 Ma
|
Large temp swings occur every 40 thousand years in early record, every 100 thousand years in later record.
|
|
vostok ice core
|
100 thousand temp cycles
-CO2 and methane track temp very closely
|
|
the last 150 years: instrumental
|
Global temp has warmed by .7 deg C since 1900 9 of the 10 warmest years on record have occurred in the last decade
|
|
What has caused temp to vary so much in the past and why is the earth warming now?
|
...
|
|
Forcing
|
a process external to earth's climate that affects the climate
-Volcanoes- large eruptions inject aerosol into the stratosphere where it lasts for many months/ a few years
-Orbital Changes- Earth's orbit around the sun changes on long time scales (40-100 thousand years)
-Changes …
|
|
Forcing: Volcanism
|
Volcanic activity: aerosols from volcanoes reduce the amount of solar radiation reaching the surface.
|
|
Forcing: Obliquity
|
the amount of "tilt" of the Earth's axis
-currently 23.5 degrees
more tiled= more solar radiation at summer pole, less radiation at winter.
|
|
Forcing: Eccentricity
|
How "elliptical Earth's orbit is
varies every 100,000 years
more elliptical= more solar radiation at perihelion (closest to the sun) and less solar radiation at aphelion (farthest from the sun)
|
|
Forcing: Solar Variations
|
increased solar irradiance every 11yrs (due to sun spot cycles in the sun)
|
|
Forcing
|
Some dominant forcing mechanism:
-Aerosols
-changes in Earth's orbit
-solar variations
-anthropogenic Greenhouse Gasses
|
|
Anthropogenic Forcing
|
Aerosol Effects: dirty burning also produces sulfate aerosols that can shade the planet. offsets positive forcing by Green house gases
|
|
Negative Forcing
|
cools planet
offsets positive forcing
|
|
Indirect aerosol effects
|
more aerosol= more CCN, which leads to brighter clouds, more reflection.
|
|
How do we know increase in CO2 is anthropogenic?
|
- emission inventories: confirm rate of increase
-ocean Carbon: has been increasing despite Warming Ocean( remember CO2 best absorbed by a COLD ocean)
|
|
how do we know its due to fossil fuel burning?
|
ratio of C14 and ratio of C13 measures ratio of C14 or C13 to more abundant C12
-C14 has a short half-life (5730 yrs) so fossil fuels have little to no C14
-C13 is not readily used in photosynthesis, so fossil fuels do not have much C13
=ratio of C14 and ratio of C13 are decreasi…
|
|
Feedbacks
|
are process that alter climate changes that are already underway.
|
|
positive feedback:
|
amplifies change
|
|
negative feedback
|
suppresses change
|
|
snow and Ice albedo feedback
|
colder temps=snow lasts longer= more solar radiation reflected= colder temps
-positive feedback
|
|
Stefan-Boltzman Feedback
|
warmer climate= more emitted radiation= climate doesnt warm as much
negative feedback
|
|
Water Vapor Feedback
|
-warmer temps and little change in Relative Humidity
-Higher mixing ratio
-enhanced greenhouse effect= warmer temps
-if continues unchecked= runaway greenhouse effect (perhaps why venus has no liquid water)
- in a warmer world, RH will probably remain constant
|
|
How much warming is produced by a doubling of CO2
|
climate sensitivity: the equilibrium global temp change at doubling of CO2
` 2-4.5 degrees C
|
|
how much CO2 will we put into the atm?
|
Preindustrial: 580Gt C
Doubling Preindustrial: gt 1180 gt C
Today: 880 Gt C (were half-way there)
CO2 doubles preindustrial levels in 60 yrs. -best case scenario
|
|
future climate change: how do we know what will happen?
|
global climate models
-divide the world into boxes, sole equations that govern weather/ climate on a discrete grid
-apply forcing based on a "story line" of future emissions
|
|
Models forced with natural and anthropogeic forcing do reproduce warming snce 1950
|
...
|
|
Future Global temp
|
will rise by about 1-1.5 deg C by 2050, 1-4 deg C by 2100
Scenarios: we dont know how our global society will evolve, so we use scenarios that describe different greenhouse gas emission pathways in the future.
|
|
Mitigation
|
necessary to avoid dangerous climate change
|
|
adaption
|
climate change is inevitable; adaption needed to minimize impacts
|
|
Possible impacts of Global climate change with REP8.5 Scenario
|
-droughts
-summer ice is gone
-habitats dissapear and extinctions follow
-heat waves, droughts, floods take human tool
-coral reefs disappear; large reduction in tropical rainforests
-extinction of up to half of all species
-partial melting of ice sheets on greenland and antarctica
|
|
Risk
|
possibility of an event occuring times its consequences
|
|
mitigation:
|
intervention to reduce the sources of greenhouse gasses or enhance their sinks
|
|
Adaption
|
adjustment of a system to moderate potential damages to take advantage of opportunities or to cope with consequences associated with climate change
|
|
Mitigation
|
ancillary benefits
-human health
-ect
|
|
Mitigation: direct benefits
|
-avoided climate impacts; uneven distribution; not coupled with location of mitigation
|
|
climate change
|
land warms faster than ocean (heat capacity)
polar regions warm more than tropics (ice albedo feedback)
|
|
Expected precipitation changes
|
wet climates get wetter
dry climates get drier
|
|
mitigation in wisconsin
|
Governors Task Force on Global Warming/ WCCAI
Mitigation strategy for Wisconsin:
Provides 63 suggested activities to achieve reductions in GHG emissions in Wisconsin
|
|
The Wisconsin Initiative on Climate Change Impacts (WICCI)
|
WICCI's mission is to generate and share info that can limit vulnerability to climate change in Wisconsin and the upper midwest
-is a highly decentralized network and boundary organization
-engages citizens, private and public decision makers and scientists
-enables better planni…
|
|
Wisconsin has warmed by 1-1.5 deg F since 1950
|
...
|
|
Wisconsin will warm by 4 deg-9 deg by mid 21st century
|
...
|
|
Wisconsin winters have warmed by 1-1.5 def F since 1950
|
...
|
|
Warming is most pronounced in winter: 5-11 deg F by mid 21st century
|
...
|
|
climate change in wisconsin: what does it mean?
|
Warmer winters= shorter ice duration
snow cover changes
shorter snow season
fewer cold. extremely cold days
|
|
Warming is least pronounced in summer 3-8 deg F by mid 21st century
|
...
|
|
Climate change in Wisconsin: what does it mean?
|
Warmer summers=
-reduced cold water fish habitat
-increased warm-water fish habitat
|
|
Extreme heat by mid century= more very hot days
|
...
|
|
Robust increase in precipitation during winter and spring
|
...
|
|
Southern Wisconsin could see a 30% increase in the number of large rainfall events
|
...
|
|
How would the vertical profile of atmospheric temperature differ if all the ozone were removed from the atm?
|
ozone heats the stratosphere from above. without any ozone, the stratosphere would not be warm, so temp would continue to decrease until the thermosphere. Also ozone absorbs UV radiation, keeping it from reaching the ground. Without ozone, a bit more radiation reaches the ground, so the s…
|
|
Briefly explain the role of the ozone layer, and the role of greenhouse gasses in making a habitably planet
|
the ozone layer shield the planet from UV radiation, which would deadly for living things.
Greenhouse gasses warm the surface of the earth by absorbing terrestrial radiation, and re-radiating some of that radiation back to the surface. Hence, they provide an additional source of energy …
|
|
List the form of energy transfer
|
...
|
|
Air inside a greenhouse stays warmer that the air outside
|
Convection, which ordinarily transports energy away from the surface, is suppressed, so energy stays in the greenhouse and the air stays warmer.
|
|
Despite adding heat to a pot of water, the temp of the water does not rise above 100degC Where is the energy going?
|
Latent heat of vaporization, energy is being used to convert liquid into a gas.
|
|
the sand on a beach warms up on a sunny afternoon
|
radiations from the sun is warming the sand.
|
|
when you walk barefoot on a beach on a sunny afternoon, the sand feels hot on your feet.
|
Conduction- energy is transferred via direct contact between your foot and the sand.
|
|
you step out of Lake Mendota after a swim on a warm, dry day, and immediately feel cooler than you did in the lake, despite the face that the air temp is warmer than the lake.
|
latent heat. Energy from your body is being used to evaporate water off of your body.
|
|
Describe how and why the surface temp of the earth would change if a gas were added to the atmosphere that:
|
...
|
|
perfectly absorbs wavelengths between 0.5 and 0.7 micrometer
|
the surface temp would decrease. this wavelength is visible light from the sun. most of that light currently reaches the surface. By absorbing that light, the surface cools because that light is absorbed before reaching the surface.
|
|
Perfectly absorbs wavelengths between 5-7 micrometers
|
the surface warms just a little. The atmosphere already absorbs 100% of radiation between 5-7 micrometers. However, the sides of absorption bands broaden, which warms the surface a little. Also, this effectively makes the atmosphere "thicker", which warms the surface a little.
|
|
perfectly absorbs wavelengths between 9-11 micrometers.
|
the surface would warm a lot. Currently terrestrial radiation between 9-11 mircometers escapes to space (the atmospheric window) so it does not contribute to the greenhouse effect. By adding a gas that absorbs between 9-11 micrometers, the greenhouse effect is substantially enhanced.
|
|
Temp changes at the surface of Earth are dominated by two cycles: the seasonal and diurnal cycles
|
...
|
|
Temp changes at the surface of Earth are dominated by two cycles: the seasonal and diurnal cycles
|
...
|
|
a. suppose the tilt of earth were 0 deg instead of 23.5 deg. how would the seasonal and diurnal cycles of temp differ from today?
|
therewould be a very weak seasonal cycle; summer would be very similar to winter. there would be a very weak seasonal cycle due to the fact that earth would be closest to the sun in january and farthest from sun in july. every day would have 12hrs or daylight and 12 hrs of night.
|
|
a. suppose the tilt of earth were 0 deg instead of 23.5 deg. how would the seasonal and diurnal cycles of temp differ from today?
|
therewould be a very weak seasonal cycle; summer would be very similar to winter. there would be a very weak seasonal cycle due to the fact that earth would be closest to the sun in january and farthest from sun in july. every day would have 12hrs or daylight and 12 hrs of night.
|
|
b. suppose the tild of the earth were 90 deg. istead of 23.5 deg.
|
the seasonal cycles would be very strong in polar regions. during the summer solstice, the sun would be directly over head for 24 hrs at the pole. during the summer solstice the entire northern hemisphere would recieve 24 hrs of sunlight and during the winter it would recieve 0 hrs. At th…
|
|
b. suppose the tild of the earth were 90 deg. istead of 23.5 deg.
|
the seasonal cycles would be very strong in polar regions. during the summer solstice, the sun would be directly over head for 24 hrs at the pole. during the summer solstice the entire northern hemisphere would recieve 24 hrs of sunlight and during the winter it would recieve 0 hrs. At th…
|
|
c. for each of the above situations, what tie of year would length of day be the same as in reality?
|
At the equinoxes- earth would experience 12hr of daylight and 12hr pf darkness no matter what the angle of Earth's axis of rotation. At the equinox, the axis of rotation is perpendicular to a line between the Earth and Sun, so the tilt doesnt matter.
|
|
c. for each of the above situations, what tie of year would length of day be the same as in reality?
|
At the equinoxes- earth would experience 12hr of daylight and 12hr pf darkness no matter what the angle of Earth's axis of rotation. At the equinox, the axis of rotation is perpendicular to a line between the Earth and Sun, so the tilt doesnt matter.
|
|
The expected afternoon temp in Agadez, Niger is 41degC
the expected afterneoon temp at Vostok Base Antarctica is -72 deg C
|
...
|
|
The expected afternoon temp in Agadez, Niger is 41degC
the expected afterneoon temp at Vostok Base Antarctica is -72 deg C
|
...
|
|
a. which location do you expect will have a higher mixing ratio? why?
|
The larger mixing ratio would be in Niger simply because Vostok is SO cold. the dewpoint temp at Vostok con only be as high as -72C, which is VERY dry.
|
|
a. which location do you expect will have a higher mixing ratio? why?
|
The larger mixing ratio would be in Niger simply because Vostok is SO cold. the dewpoint temp at Vostok con only be as high as -72C, which is VERY dry.
|
|
Which location do youexpect will have a higher relative humidity? why?
|
Vostok probably has the higher relative humidity. Vostok is surrounded by water (ice) and the temp is SO cold that it would take very little moisture at all to be saturated. On the other hand, Agadez would take an enormous amount of moisture to become saturated because it is SO hot.
|
|
Which location do youexpect will have a higher relative humidity? why?
|
Vostok probably has the higher relative humidity. Vostok is surrounded by water (ice) and the temp is SO cold that it would take very little moisture at all to be saturated. On the other hand, Agadez would take an enormous amount of moisture to become saturated because it is SO hot.
|
|
c. Which location do you expect will have a higher dew point temp. why?
|
Agadez has a higher dew point temp, probably. The highest dew point temp can be in Vostok is -72C, which is VERY low.
|
|
c. Which location do you expect will have a higher dew point temp. why?
|
Agadez has a higher dew point temp, probably. The highest dew point temp can be in Vostok is -72C, which is VERY low.
|
|
On a warm summer day, one city experienced a diurnal temp range of 20C while another city experienced a daily range of 5C. Once city is Miami FL and the other is Roswell NM. Which city probably had the highest daily range, and which one had the smallest? why?
|
Miami has the smaller temp range. During the day, Miami is surrounded by ocean which has a very high heat capacity (so it absorbs a lot of energy before it warms substantially) compared to Roswell, which is mostly desert. At night, the high humidity in Miami enhances the greenhouse effect…
|
|
On a warm summer day, one city experienced a diurnal temp range of 20C while another city experienced a daily range of 5C. Once city is Miami FL and the other is Roswell NM. Which city probably had the highest daily range, and which one had the smallest? why?
|
Miami has the smaller temp range. During the day, Miami is surrounded by ocean which has a very high heat capacity (so it absorbs a lot of energy before it warms substantially) compared to Roswell, which is mostly desert. At night, the high humidity in Miami enhances the greenhouse effect…
|
|
Classify the following fog situations
|
...
|
|
Classify the following fog situations
|
...
|
|
a. while camping on the coast of Maine, you notice clouds on the horizon and a strong wind blowing from the ocean in the evening. when you wake up, the wind is still blowing from the ocean and it is very foggy.
|
Advection Fog.
|
|
a. while camping on the coast of Maine, you notice clouds on the horizon and a strong wind blowing from the ocean in the evening. when you wake up, the wind is still blowing from the ocean and it is very foggy.
|
Advection Fog.
|
|
On a cold day you can see your breath
|
Mixing/Steam/ evaporation fog
|
|
On a cold day you can see your breath
|
Mixing/Steam/ evaporation fog
|
|
on some very clear and calm autumn mornings, you notice a thin layer of fog on the ground in the countryside.
|
Radiation Fog
|
|
on some very clear and calm autumn mornings, you notice a thin layer of fog on the ground in the countryside.
|
Radiation Fog
|
|
While jogging out to picinic point on late autumn morning with a light cold wind from the north, you notice wisps of fog rising off of Lake Mendota
|
mixing/ steam/ evaporation fog
|
|
While jogging out to picinic point on late autumn morning with a light cold wind from the north, you notice wisps of fog rising off of Lake Mendota
|
mixing/ steam/ evaporation fog
|
|
to find mixing ratio= use dew point temp
to find saturated mixing ratio= use actual temp
to find relative humidity= divide the mixing ratio over the saturated mixing ratio
|
...
|
|
to find mixing ratio= use dew point temp
to find saturated mixing ratio= use actual temp
to find relative humidity= divide the mixing ratio over the saturated mixing ratio
|
...
|
|
would the reported sea level pressure be higher, lower or the same on a cold winter day?
|
Temp decreases, density increases. If density of air increases surface pressure increases. On a cold day, Sea Level Pressure is higher.
|
|
would the reported sea level pressure be higher, lower or the same on a cold winter day?
|
Temp decreases, density increases. If density of air increases surface pressure increases. On a cold day, Sea Level Pressure is higher.
|
|
True or False:
a. The only horizontal force that can increase the wind speed is the presure gradient force.
|
True: Coriolis changes direction of wind, and friction slows wind down, so only PGF can speed wind up.
|
|
True or False:
a. The only horizontal force that can increase the wind speed is the presure gradient force.
|
True: Coriolis changes direction of wind, and friction slows wind down, so only PGF can speed wind up.
|
|
b. Winds always circle counter clockwise around a low pressure system.
|
False, force balance shows us winds blow counterclockwise around a low in the Northern Hemisphere but clockwise around a low in the Southern Hemisphere.
|
|
b. Winds always circle counter clockwise around a low pressure system.
|
False, force balance shows us winds blow counterclockwise around a low in the Northern Hemisphere but clockwise around a low in the Southern Hemisphere.
|
|
c. In the northern hemisphere, the Coriolis force causes surface winds to veer to the left, relative to the geostrophic wind.
|
False- friction causes surface winds to veer to the left of geostrophic wind.
|
|
c. In the northern hemisphere, the Coriolis force causes surface winds to veer to the left, relative to the geostrophic wind.
|
False- friction causes surface winds to veer to the left of geostrophic wind.
|
|
d. the Northern and southern hemisphere jet streams both tend to be westerly.
|
True: in both hemispheres PGF points to poles therefore Coriolis points towards equator. Resulting jetstreams will be westerly in both hemispheres.
|
|
d. the Northern and southern hemisphere jet streams both tend to be westerly.
|
True: in both hemispheres PGF points to poles therefore Coriolis points towards equator. Resulting jetstreams will be westerly in both hemispheres.
|
|
why are the tropics not continually getting warmer and polar regions continually getting colder.
|
Poleward heat transport- many different processes contribute such as mid-latitude cyclones and ocean currents.
|
|
why are the tropics not continually getting warmer and polar regions continually getting colder.
|
Poleward heat transport- many different processes contribute such as mid-latitude cyclones and ocean currents.
|
|
why are the surface waters along the equator generally colder than the water on either side of the equator?
|
Easterly winds create net water transport away from the equator, to the north in the N. Hemisphere and to the south in the S. Hemisphere= divergence of water.
-this dvivergence creates upwelling along the equator thus water temp right along the equator is colder than water to either sid…
|
|
why are the surface waters along the equator generally colder than the water on either side of the equator?
|
Easterly winds create net water transport away from the equator, to the north in the N. Hemisphere and to the south in the S. Hemisphere= divergence of water.
-this dvivergence creates upwelling along the equator thus water temp right along the equator is colder than water to either sid…
|
|
Briefly describe each of the following phenomenon, and list the physical processes responsible for causing the phenomenon.
|
...
|
|
Briefly describe each of the following phenomenon, and list the physical processes responsible for causing the phenomenon.
|
...
|
|
a. Inferior Mirage
|
Refraction: Light enters less dense, hot air near surface and gets bent (refracted)
|
|
a. Inferior Mirage
|
Refraction: Light enters less dense, hot air near surface and gets bent (refracted)
|
|
Sundogs
|
Refraction: Light refracts through hexagonal ice crystals high in atmosphere.
|
|
Sundogs
|
Refraction: Light refracts through hexagonal ice crystals high in atmosphere.
|
|
Rainbows
|
refraction and reflection: light enters water drop, gets refracted, then reflects off back of drop
|
|
Rainbows
|
refraction and reflection: light enters water drop, gets refracted, then reflects off back of drop
|
|
the blue sky
|
scattering- short wavelengths (blue) is scattered more easily towards your eye
|
|
the blue sky
|
scattering- short wavelengths (blue) is scattered more easily towards your eye
|
|
Red sunsets
|
scattering- sun low on horizon means light has to travel through more atmosphere- more blue light scattered away than red (means you see more red)
|
|
Red sunsets
|
scattering- sun low on horizon means light has to travel through more atmosphere- more blue light scattered away than red (means you see more red)
|
|
classify the following as positive feedback, negative feedback, positive forcing or negative forcing.
|
...
|
|
classify the following as positive feedback, negative feedback, positive forcing or negative forcing.
|
...
|
|
As oceans warm,they absorb less carbon dioxide
|
Positive feedback
|
|
As oceans warm,they absorb less carbon dioxide
|
Positive feedback
|
|
the average relative humidity in a warmer world is expected to be the same as the average relative humidity abserved today (hint: what does this mean for the average total water vapor in the atm, and hance the amount of greenhouse gas in the atm?
|
positive feedback
|
|
the average relative humidity in a warmer world is expected to be the same as the average relative humidity abserved today (hint: what does this mean for the average total water vapor in the atm, and hance the amount of greenhouse gas in the atm?
|
positive feedback
|
|
Anthropogenic aerosols can act as cloud condensation nuclei. Increases in these aerosols lead to more optically thick clouds and hence higher planetary albedo.
|
negative forcing
|
|
Anthropogenic aerosols can act as cloud condensation nuclei. Increases in these aerosols lead to more optically thick clouds and hence higher planetary albedo.
|
negative forcing
|
|
Volcanic aerosols tend to reflect more solar radiation
|
negative forcing
|
|
Volcanic aerosols tend to reflect more solar radiation
|
negative forcing
|
|
As earth;s surface warms, it emits more radiation
|
negative feedback
|
|
As earth;s surface warms, it emits more radiation
|
negative feedback
|
|
as permafrost melts, methane is released to the atm.
|
positive feedback
|
|
as permafrost melts, methane is released to the atm.
|
positive feedback
|
|
Why will digging a tree that was buried in the ice age and burning it affect the atm concentration of co2?
|
growing a tree will remove some carbon from the current atm therefor the tree from the ice age will increase the cO2 concentration of the current atm more. ( in other words, the ice age tree will add New carbon to the system that was not present prior to burning.
|
|
Why will digging a tree that was buried in the ice age and burning it affect the atm concentration of co2?
|
growing a tree will remove some carbon from the current atm therefor the tree from the ice age will increase the cO2 concentration of the current atm more. ( in other words, the ice age tree will add New carbon to the system that was not present prior to burning.
|
|
Typical Frontal passages weather:
Cold Front
Before passage
-temp is warm
-dew point temp is high
-sea level pressure is falling
-Wind direction- southerly
-clouds- cumulonimbus
-precipitation- heavy near front
After Passage
-temp is cooler
-dew point temp is lower
-s…
|
...
|
|
Typical Frontal passages weather:
Cold Front
Before passage
-temp is warm
-dew point temp is high
-sea level pressure is falling
-Wind direction- southerly
-clouds- cumulonimbus
-precipitation- heavy near front
After Passage
-temp is cooler
-dew point temp is lower
-s…
|
...
|
ATM OCN 100: Final Exam