Meteorology
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Land Vs. Water
N. Hemi- 60% Water, 40% Land
S. Hemi- 81% Water, 19% Land
Water heats up and cools down slowly-specific heat
N. hemi has higher highs and lower lows than s. hemi
Composition and Evolution of our ATM
78%N
21%O
Traces of: S, Ar(other noble gasses), CH4, CO2, H2O
Sources of our ATM:
Volcanoes- SO2, CH4
Meteorites
Lightning
Erosion
Mauna Loa Graphx-axis= time
y-axis= CO2 concentration in ppm
Shows: steady and ever increasing slope
Yearly jogs in slope indicate seasons. Peak per year = fall and Valley per year = spring.
Aerosols- suspended fine(small) particles in the ATM. Solid particles dissolved in air that are
too small to see, but can get in your body.
React with other gasses to make a hole in our ozone layer(CFC’s) and acid rain(Sulfur).
Can affect climate by affecting cloud formation(they help make clouds) and reflecting sunlight.
Sources of Aerosols:
Volcanoes, Dust Storms, Forest/Grass Fires, All Fossil Fuels Burning, Factories, Dead
Skin Cells, Space Dust
Hydrologic(water) Cycle- no start/stop, but continuous procedure where water changes forms
and places, but is never lost or gained.
Condensation: gas to liquid(clouds)
Precipitation: H20 back to earth
Evaporation: liquid to gas
Transpiration: evap. from plants
Also includes sinks(places where it looks like water is removed from the cycle): ocean,
groundwater, the rock cycle, glaciers
Hydrologic Cycle- describes the continuous motion of water above and below the
surface(powered by the sun)
Evaporation- water transported from the surface to the ATM(liquid to gas). Affected by
temp, humidity, amount of moisture available.
Condensation(vaporization)- transfer of H2O from gas to liquid. Affected by temperature
and amount of moisture available. Condensation creates clouds.
Precipitation- buildup of moisture in cloud. Transfer of water from ATM to ground.
Transpiration- water evaporates from the leaves of plants
Pressure Vs. Altitude:
Air gets thinner when you go higher. It’s going to weigh things down. For every height increase
there is less air on top of you. As the air on top of you decreases the air will expand.
Air pressure decreases with altitude.
Layers of the atmosphere
In the troposphere the temp goes down
The top of the mesosphere is 80 km In the mesosphere the temperature decreases this is
where the meteors get burned.
The thermosphere the shuttles fly here and the temps go up.
at 10,000ft, pressure is 65% sea level. At 30,000ft(top of Mt. Everest) there is less than 30% air
pressure left. As you leave the earth, there is less ATM above, so there is less pressure, which
allows air to expand. The decrease in pressure with height forces the temp to drop.
Troposphere is 80% mass of the atmosphere (0-10km). All earth’s weather is in the
troposphere. Stratosphere (10-30km) has the ozone layer. Planes fly here. The temperature
increases. Mesosphere (30-55km) is where meteors get burned. The temperature decreases.
Thermosphere (up to 160km) Space shuttles fly here. Temps increase here. Exosphere (55120km) is the boundary of earth/space.
Heat: form of energy, can transfer between objects
Parcel of air: imaginary volume of air used in meteorology to explain the ATM.
Temperature: degree of “hotness” or “coldness” of an environment- measure of the average
kinetic(moving particles)energy. (what we feel as hot or cold)
Temperature scales:
Fahrenheit- Boiling Pt = 212F
Freezing Pt= 32F
Absolute Zero= 460F Most of Life is Spent Between 100F and 0F
Celsius- boiling point of water= 100C
Freezing point = 0 C. absolute zero = -273 C Most of Life is Spent Between 35C and -10C
Kelvin- boiling point= 373 K freezing point= 273 K. absolute zero = 0 K. Most of Life is
Spent Between 263K and 310K.
Specific heat: The amount of heat required to raise one gram of a substance by 1 C.
Low specific heat = rocks, sand, pavement
High specific heat = air, water, liquids
Convection: transfer of heat in a vertical direction. Form of heat transfer, works in a vertical
direction. Hot material rises and cool material falls.
Sensible heat- a change in the temperature because of a change in energy.
Conduction- transfer of heat between molecules that are touching.
Examples: metal, soil,
Poor conductors: water, air,
Radiation- transfer of energy through waves/particles through space.
Advection- transfer of energy that works horizontally. Caused by pressure differences which are
caused by temperature which are caused by unequal heating of the earth.
Adiabatic cooling- cooling of a parcel of air as it rises. As air rises there is less pressure on it so
it expands, reduces air pressure and cools.
Lapse Rate: The rate of decrease of temp with height equals 10C/ 1000m for dry air. Lapse rate
equals 6c per 1000m for moist air.
Stefan- Boltzmann Law: E = T4 hot objects emit a lot more energy then cool objects.
Wien’s Law: objects of different temperatures emit different color light. Hot objects emit short
wave length light. Short wave length light has high energy
The Seasons:
Are based on the 23.5 degree tilt of Earth’s axis. During the s-hemi summer the s-hemi
receives 3X the light of the n-hemi.
Vernal equinox:
Late March marks the beginning of Spring.
Autumnal equinox:
Begins late September and marks the beginning of Fall.
Solstices:
Winter (late December) = start of winter, Summer (June) = start of summer (apogee)
Atmospheric Window:
Wave lengths of light that go through the atmosphere. There is a window for: IR,
sunlight, and radio waves. There is no window for UV, X-rays, Gamna rays.
a parcel of air rising gets cooler. Air pressure decreases with alt. That causes a parcel of air to
expand.
LAPSE rate- decrease in temp with height. When air is dry the lapse rate is 10c/1000m. When
air moist the lapse rate is 6c/1000m. The dryer the air the steeper the lapse rate.
Diabatic cooling- is moist lapse rate.
Stefan-Boltzmann Law- E=T4- High temps= high E.
Wein’s Law= short wavelengths are emitted by hot objects
Albedo- reflectivity of a surface. High albedo= metal
Low albedo= rubber, black paper
The higher the albedo of a surface, the cooler it stays.
The Seasons
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earth orbits sun on tilted axis of 23.5 degrees
earth does not receive sunlight evenly
Summer = n. hemi. Tilted towards sun
Winter = n. hemi. Tilted away from the sun
Fall/Spring = both hemis. Receive equal light
June 21st longest day in n. hemi. w/ most direct sunlight- summer solstice
Dec. 21st shortest day in the n. hemi. w/ the least amount of sunlight- winter solstice
Sept. 22nd autumnal/ fall equinox
March 22nd vernal/ spring equinox
Atmospheric window- the wavelengths of light that can go through our atm.
No Window- x-ray, gamma, uv
Window – visible light, radio light, infrared (partial)
The Greenhouse Effect(GHE)
Rise in temperature because of gasses present in our ATM. The main gasses are CO2,
methane, nitrous oxide, H2O. All of those gasses transmit sunlight(short wavelengths). All of
these gasses absorb and then emit earthlight. With the GHE, earth’s average temp is 57F.
without the GHE, earth’s temp would plummet to 0F. When people talk about the effect humans
have, they are talking about global warming which includes the added anthropogenic GHG’s.
Chapter 3 Notes
$Temperature$
Daily Mean Temp- Average of the daily max and min. Temps
Annual temp cycle- Seasonal change in temps.
Caused by tilt of earth
Annual mean temp- The average temp. for the year. Add up monthly means and divide by 12.
Temp range- Difference between max and min
Factors that effect daily (diurnal) temp range- Cloud cover/ Reduces range, Wind/Reduces
range, Humidity/ Reduces range
Factors that effect yearly temp range1.
Latitude
2.
elevation
3.
Being near water/sand
4.
Persistent clouds
5.
6.
7.
Surface type
Persistent Humidity
Aspect
Interannual Temp Changes(Global Climate Change)
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El Nino/ La Nina changes in the ocean temp.
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Volcanoes add chemicals to our atmosphere that blocks sunlight
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Glaciers make earths albedo go way up
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Sunspots make earth warmer
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Earths tilts various between 21-25 degrees. More equals colder
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Earths orbit flattens which makes earth colder
Carbon dioxide
Water temperature increases/climate would change
Glaciers melting-when they melt earths albedo decreases
El nino
Volcanoes-make the earth colder, by putting gases in the air that reflect sunlight
Earth’s tilt wabbles
Earth’s orbit gets more elliptical which makes the earth colder
Temperature Inversions:
Normal Conditions: Temperature Drops with Height
Inverted Conditions: Temperature Increases with Height
How?Why?Where?-occurs when less dense(warm) air moves over more dense air (cold)
Warm front-when the clouds are warmer than the ground
Cold front-cold air moves in at ground underneath warm air
Nocturnal inversion- the winter season especially October-March, longer nights earth cools
faster than air
Just before daybreak is the most inverted air.
Valley inversion- cold air gets trapped between mountains
Lapse Rate- rate of decrease in temp with height. 10C/Km when dry. Will be less if humid.
Stable Air- actual lapse rate less than 10C. Air will not rise- no clouds
Unstable Air- actual lapse rate greater than 10C. Air will rise and form clouds.
Wind Chill- how much the wind makes the temp feel colder. Caused by blowing away the warm
conducted air your body creates.
Farmers Vs. The Cold- 1-spray crops to freeze them because the latent heat of freezing is
exothermic.
2- cover them with tarps
3- fans that mix the air
Chapter 4 Measuring Moisture in the Air
Mixing Ratio- ratio of mass of moisture in air vs. mass of dry air. This is an absolute value and
does not depend on temp.
Saturation Vapor Pressure- pressure exerted by a gas on its container. Saturation means the
most moisture air can hold before condensation occurs. Relative term because it depends on
how cold/hot the air is. Cold air can’t hold much moisture, so a little bit of moisture is a high
vapor pressure. Hot air can hold a ton of moisture, so the same little bit of moisture seems
bone dry.
Evaporation- reverse of condensation- when water is turned to a gas.
Factors that affect evap rate:
1sun/heat
2wind
3moisture already in air
4amount of water
5shape of water
Dew Pt- temp at which a given parcel of air must be cooled to to create condensation
Dew Pt Depression- difference between air temp and dew pt temp(always lower than air temp)
Lab ReviewSurface Area-What is the effect of surface area on evaporation rate?
More surface=more evaporation
Constant- ml of water, air pressure, air temp
Control- the least s.area
Temperature- What is the effect of temp on evaporation rate?
Hotter=more evap
Constant- amount of water, surface area
Control- coldest trial
Cloud FormationCome from evaporated water.
Must be higher than 50ft.
Have to have rising air that cools adiabatically.
Rising air cools to reach its dew pt and condenses into droplets.
Condensation Nuclei- smoke, pollen, pollution, dust. These particles provide a
surface for the vapor to condense around.
Situations that help clouds to form(cause air to rise):
1Recent Rain
2Solar Energy(heat)
3Mountains
4Fronts(warm or cold)
Cloud TypesLow- stratus(flat or layered), stratocumulus(puffy, tall), nimbo(rain)stratus(low,
flat, raincloud)
Middle- alto(high)stratus(layered), cumulonimbus(puffy, tall raincloud),
altocumulus(high, puffy- lower than a cirrus, but higher than a stratus)
High- cirrus(high, thin, icy), cirrocumulus(high, wispy, puff), cirrostratus(high,
layered cloud)
Special Clouds- contrails- aircraft exhaust, lenticular- lens- form as wind goes past a mountain
or hill, congestus- warm, moist air rising in cauliflower shapes
Precipitation Types
Liquid- rain- cloud temp(either above or below 32F) air temp(above 32F)ground temp(above
32F)
Freezing- freezing rain- cloud temp(usually below 32F)air temp(warmer than 32F)ground
temp(below 32F)
Frozen- sleet- cloud temp(below32F) air temp(above 32F) ground temp(below 32F)A thicker
layer of ATM is below 32F for sleet, therefore it is frozen before it hits the ground and makes a
“tink” sound when it hits.
Snow-cloud(below 32F) air(below32F) ground(below 32F)
Hail- cloud(below 32F) air(above32F) ground(above 32F)- forms in the updraft of severe tstorms in the summer.
Nimbus(root)- raining
Cumulo(prefix), cumulus(root)- puffy, taller rather than wide
Alto(prefix)- high
Strato(prefix), stratus(root- layered, sheetlike
Cirro(prefix), Cirrus(root)- curly, wispy
Altostratus= high layered cloud
Cumulonimbus= puffy, raincloud
Cirrus= highest, wispy, icy
Stratocumulus= puffy, layered cloud
Cirrostratus= thin, wispy, layered(sundog- icy ring around sun)
Nimbostratus= raining, sheet cloud
Chapter 5 Weather Instruments
ASOS- automated surface observing system.
Resistance thermometer- temp is sensed by using predictable changes in the resistivity
of a wire at different temps. (Pt)(Ni)
Alcohol thermometer- used to measure temps. From -115C-785C. Liquids are used
because they expand and contract easily.
Rules for Placement of Thermometers-6ft above ground
-away from structures
-in the shade
Dew point hygrometer- an instrument that measures dew point by measuring the temp. at
which water vapor condenses
Psychrometer- measures humidity by using two thermometers. One having a wet bulb
(should be colder) and one having a dry bulb (should warmer)
Mercury barometer- an instrument that determines atmospheric pressure using liquid
(Hg)
Aneroid barometer- measures air pressure by using thin metal which expands and
contracts due to pressure changes
Anemometer- measures wind speed by using cups
Wind vane- measures wind direction
Wind sock- measures direction and speed
Rain gauge- measures liquid precipitation that falls
RadiosondeWeather MapsCeilometer- measures the height of the lowest cloud. Can help determine precipitation
type and amount.
Visibility Sensor- measures the presence, intensity and duration of fog. Give secondary
info on precipitation rate.
GEO- Geostationary Earth Orbit(satellite)- Orbit earth exactly as fast as earth spins, so it
appears in one spot. GEO’s orbit around the equator and are designed to track
hurricanes. Orbit height is 35,000km or 20,000mi.
LEO- Low Earth Orbit- orbit at 850km or 500mi. Provide very clear pictures. Move
around the earth so they provide information on more than one storm, but none for any
length of time. Also, they orbit from pole to pole so they give info on winter storms.
Visible Satellite- provides a picture from space of how the earth and clouds would
actually look from space. Useless at night.
Infrared Satellite- uses heat to show cloud height. Cold weather clouds(stratus) grow
wide rather than tall and show up as warm clouds. Warm weather clouds(cumulus) grow
tall rather than wide and show up as cold clouds.
Water Vapor Satellite- shows moisture as bright green and dry air as black and really dry
as orange. Excellent because it clearly shows the general flow of airmasses.
RADAR- uses Radio Detection and Ranging to tell where precipitation is.
Doppler RADAR- uses the Doppler effect to measure speed of storms.
Wind Profiler- represents rotation among thunderstorms as signs of tornadoes.
Wind Chapter 6
Gravitational Force- force of attraction between all objects in the universe. The strength of the
force is based on mass and distance. The earth pulls strongest on everything we see because
we are VERY close to the center of the earth. The next strongest pull on objects is from the
moon as seen by the tides. The next strongest gravitational pull is from the sun.
Pressure Gradient Force(PGF)- acceleration of air due to pressure
-Usually responsible for excelling a parcel of air from a high pressure to lower
Coriolis Force- Changes the direction but not the overall speed of anything moving with respect
to the ground (including air)
-Apparent reflection of moving objects when they are viewed from a rotating reference frame.
-Objects deflect to the right in the northern hemisphere
-Objects deflect to the left in the southern hemisphere
-The amount of deflection the air makes is directly related to both the speed at which the air is
moving and its latitude.
Frictional Force- caused by air flowing over a rough surface, reduces wind speed, works
opposite the flow of wind
Surfaces with High Friction:
Mtn’s/Volcanoes
Bldg’s
Trees
Surfaces with Low Friction:
Water(ocean/lake)
Grassland(Neb/Iowa/Kansas)
Centrifugal Force- outward force associated with rotation- seen in meteorology as air flows from
H to L pressure and is curved by coriolis
Hydrostatic Balance- balance between gravity and upward PGF caused by high pressured air at
earth’s surface vs. low pressured air at altitude
Geostrophic Balance- wind that results from balance between PGF and Coriolis(basically, the
wind we feel on earth)
Buys Ballot’s Law- Wind flows at right angle to PGF. Way of determining where low pressure is by
putting back to wind and reaching out with left hand that will point to where storm is.
Gradient Balance- A more accurate method of determining the wind because it is a three way balance of
Coriolis, PGF and centrifugal force. It is the wind you feel when you stand on Earth.
Guldberg-Mohn Balance- The three way balance of Coriolis, PGF and Friction. Because of friction wind
flows across iso-bars.
Scales of MotionMicroscale- smaller, 1 km or less, tornado
Mesoscale- 1km-100’s km, thunderstorms, fronts, sea/land breezes, snow storms, hurricanes
Synoptic- 100’skm-1000’s km, when the total cloud outflow surrounding a storm is included, it is
synoptic scale
Global- a wind is an established pattern of weather over a given area over time
Local BreezesLand Breeze- at night, sand cools faster than water. This creates L over the water and H over the
sand. PGF goes from H to L so at night there is a breeze from the land to the sea.
Sea Breeze- during the day, sand heats faster than water. This creates L over the sand and H
over the water. PGF goes from H to L so during the day there is a breeze from the sea to the land.
Hadley Cells- direct sunshine at equator causes high heat, low pressure, rising air. As that air rises it
becomes high pressure spreading air. That air sinks at 30N. Half of that sinking air heads S and is bent by
coriolis and forms the trade winds. The other half of that sinking air heads N and is bent by coriolis and
forms the westerlies that bring us our weather.
Jet stream- Fast flowing stream of air moving from West to East
Polar Jet- W to E. Stronger than subtropical jet, AVG 600 N
Subtropical Jet- W to E. AVG 300 N
Doldrums- A belt between 5 N and 5 S where neither trade wind dominates. Doldrum means no air
movement.
Subtropical high- Heavy sinking air at 30 N/S where air from Hadley Cell descends.
Rossby Waves- Giant meanders in high-altitude winds that are a major influence on weather.
Patterns of Rossby Wave
1.
2.
3.
4.
Zonal Flow- General w to e pattern of air. Northern areas are cold, southern areas are
warm. A small amplitude wave
Meridional Flow- the general flow pattern is extremely high amplitude. The weather
becomes extreme.
Split Flow- Northern and Southern branches of jet stream have different patterns.
Blocking Pattern- Nearly stationary pool of air that blocks the flow of weather from w to
e. Leads to both floods and droughts.
Zonal Index- Positive=Zonal, Negative=Meridional
ITCZ- (Intertropical Convergence Zone) Formed by trade winds meeting at the equator. Causes clouds
from the air converging, shifts seasonally with the sun.
Monsoons- A seasonal wind that reverses therefore creating a climate of rainy and drought. Persistent
wind flowing off the ocean and uphill creates rainy season and persistent wind flowing downhill creates
a dry season.
El Nino- Periodic alteration in the trade winds that alters the globe’s weather. Invloves more warmth in
SA and coolness in SE Asia. Both of which are extremely damaging to the culture there. SE Asia
experiences a drought which leads to crop failures and SA will have flooding.
Upwelling- A wind driven surface current that pushes warm water away which brings in cold water
which is usually nutrient rich. Instead of crop failure there is no catch which would lead to starvation.
PDO- (Pacific Decadal Oscillation) Multi- decade shifting of the climate in the pacific. A larger cycling of
the waters of the Pacific than El Nino.
AO- (Arctic Oscillation) H and L pressures swap from Arctic to Tropics. This causes blocking pattern in NA
and therefore big snow storms for NE and warmth in the Arctic.
La Niña- Stronger than normal tradewinds. (amplifies the normal conditions)
Hurricane (Atlantic)/Typhoon(Pacific)/Cyclone(Indian) formation- forms over warm water (78F).
Warmth is fuel/energy.
Thunderstorm complex
High humidity
low air pressure- allows air to rise, cool, condense
rotation- change in direction and speed of wind
preexisting condition- trough of low pressure in place allows other ingredients to form.
Stages:
1.
2.
3.
4.
Wave- no closed formation, no structure
Tropical depression- organized circulation with sustained winds less than 38mph.
Tropical storm- organized circulation with winds between 39 and 73mph
Hurricane- closed circulation with eye and winds over 74mph
a. 1- 74-95mph
b. 2- 96-110mph
c.
3- 111-130mph
d. 4- 131-154mph
e. 5- 155+mph
Structure of a hurricane
Spiral- counterclockwise rain bands
Eye wall- surrounds the eye consisting of most intense rain and wind
Eye- calm winds, warmest part of storm, sunny, clear, high pressure sinking air
Destructive forces of hurricane
1.
2.
3.
4.
5.
6.
1.
Wind- north east quadrant is most dangerous because storms forward motion adds to
wind speed
Storm surge- high winds blowing on shore plus low pressure allows water to rise quite a
bit.
Rain
Tornadoes upon landfall
Mudslides in mountainous
Socioeconomic factors
a. Infrastructure to deal with damage.
b. Structural stability determines how much damage a given wind speed does