Meteorology Notes

Meteorology Unit

Unit 1 - Winds

• Definition of Winds: The movement of air from areas of high pressure to low pressure.

• Types of Winds:

  • Global Winds: These are large-scale wind patterns influenced by the rotation of the Earth and solar heating.

  • Local Winds: These are smaller-scale winds created by local geographic features and temperature differences.

Harmonious Cycle of “Air”

• Photosynthesis

  • Using CO2 and releasing O2

• Respiration (Breathing…)

  • Using O2 and releasing CO2

Atmospheric Composition

• Crucial part in the water cycle

• All weather takes place in atmosphere

  • Local atmospheric conditions vs. regional atmospheric conditions

• Ozone layer (O3)

  • In upper atmosphere

  • Protects us from the energy UV radiation from Sun

  • Keeps temperature moderate

  • Like a blanket around the Earth

• Made up of gases that make sound possible (and breathing….)

Composition of Air

• Nitrogen and Oxygen make up 99% of the composition of our air.

• CO2 is an incredibly important part however small the percentage.

  • CO2

    • We exhale, animals exhale

  • CO

    • More dangerous than CO2

    • Small amount in the air can cause death

    • When you breath it in it replaces the oxygen in your body..

    • Carbon Monoxide Detectors

    • Both are odorless gasses that can cause harmful effects

    • Open flame in enclosed space, space heaters, furnaces improperly vented, boilers, vehicle exhaust

CARBON DIOXIDE OVER 800,000 YEARS

• Graph depicting carbon dioxide levels over 800,000 years.

• Shows fluctuations between ice ages and warm periods.

• Indicates a sharp increase in CO2 levels in recent years (2019 average of 409.8 ppm) compared to the highest previous concentration (300 ppm).

Sketch Graph

Humidity

• Amount of water vapor in the air by percentage.

• Humidity changes with the temperature.

  • Higher temp air parcels can hold more moisture

  • Lower temp air parcels have a much lower amount of moisture it can keep suspended.

  • What is the humidity in your house?

  • How does the humidity affect you?

Other things in the Air?

• Dust

• Soil

• Fecal matter

• Metals

• Salt

• Smoke

• Ash

• Other solids…really small particles

• Water vapor can condense and form around these solid particles form rain drops…

• ….Yep…. you breathe that all in…….

Pressure and Density of Air

• Sea Level

  • Level with the Oceans

• Altitudes

  • How far above or below sea level.

• Air density decreases with higher altitudes

  • Decreases with lower

• Gravity pulls molecules toward earth…causing more dense air closer to the surface.

• Gasses as sea level experience the pressure of all the atmospheric gas above it.

  • Aka atmospheric pressure (pushes in all directions)

15.2 Atmospheric Layers Vocabulary

• aurora

• exosphere

• inversion

• ionosphere

• magnetosphere

• mesosphere

• ozone layer

• solar wind

• stratosphere

• temperature gradient

• thermosphere

• troposphere

Why does warm air rise?

• Molecular level what is happening?

  • Cold air is dense

  • Warm air less dense

  • Kinetic theory of matter.

Temperature Gradient

• Diagram showing the temperature gradient across different altitudes in the atmosphere.

How do we collect data?

• Mention of attaching a parachute, likely for weather instruments.

Atmospheric Layers

• Draw a Diagram showing different atmospheric layers:

  • troposphere

  • stratosphere

  • upper atmosphere

  • limb

  • outer space

Troposphere

• Temp: Highest near the Earth’s surface, decreases with altitude

• Includes the air we breathe!

• Weather takes place here.

• Hot air balloons and airplanes can be found here.

• Warmth from Earth

Stratosphere

• Ozone found here

• Temperature rises as you go up

• Sun heats

• Volcanic ash can remain here for years

• Very little mixing

• Planes in lower portion due to low turbulence

• Stable temp

Ozone

• Ozone protects life on Earth

• UV exposure

• UVB, UVC

Mesosphere

• Temp. decreases with alt.

• Few gas molecules

• Heat source from stratosphere

• Cold

• High UV

• No oxygen

• Meteors burn up here

Thermosphere

• ISS orbits here

• Low density of molecules

• Cold

• Aurora’s form here

• Ionosphere here to exosphere

  • Solar radiation ionizes gas molecules to create cations and electrons

Ionosphere

• Extends from Mesosphere to Exosphere

• Solar radiation ionizes gas molecules to create cations and electrons

• Free ions=interesting characteristics

  • Radio waves bounce off (radio wave communication work because of this!)

• Solar storms cause auroras here (protons and electrons flowing out from Sun)

• Solar wind colliding here with our magnetic field cause the Van Allen Belts

  • 2 doughnut shaped regions of ionized particles in the atmosphere

• Aurora borealis, Aurora Australis

• Free electrons flow as electric currents

Exosphere

• From Thermosphere and beyond

• Outermost

• Solar wind

  • Protons and electrons moving out from sun

Thermosphere

• Hottest Temperatures in Atmosphere

• Temperature Increase

• Gamma and X-Rays Absorbed

• Aurora Borealis

Local and Global Winds

• Read & Notes

• Sea Breeze Gizmo Introduction.

Global Wind Belts

• Shorter Sections with Practice questions

• Early Explorers

  • How did Trade wind get their name?

    • Sailors using them for commerce.

  • Took the winds that would take them to their destination fastest.

  • East to West Good Visual

Global Wind Belts & Atmospheric Circulation Cells.

• A: Tropopause in arctic zone

• B: Tropopause in temperate zone

• Diagram showing

  • Polar cell

  • Mid-latitude cell

  • Hadley cell

  • Intertropical convergence zone

  • Westerlies

  • Northeasterly Trades

  • Southeasterly Trade

Global Wind Belts

• Blow in belts circling the planet.

• Locations of wind belts.

  • Correlate with the atmospheric circulation cells.

  • Air moves from High to Low pressures.

    • Sun hitting equator consistently causes warm rising air.

      • Rising air causes low pressure.

    • Colder poles cause sinking air.

      • Sinker air causes high pressure.

  • Global Atmospheric Circulation

    • Three-Cell Circulation Model

      • Meteor William Ferrel

      • Old and mildly outdated model

Three-Cell Circulation Model

1. Polar Cell

   • Polar cooling.

   • Polar Easterlies.

     • From N to S & E to W.

2. Ferrel Cell

   • Westerlies.

     • From S To N & W to E.

3. Hadley Cell

   • Equatorial heating.

   • Trade Winds.

     • NE to SW

Draw the 3 cells with the jet streams labeled.

Global Winds & Precipitation

• Amount of precipitation per region

  • Depends on the 6 Circulation Cells

• Rain Common in Low pressure Regions

  • Due to rising air.

• High pressure regions

  • Air sinking causes evaporation

    • Dry region

Coriolis Effect

Polar Front

• Junction between Ferrel and Polar cells.

• Low Pressure Zone

  • Relatively warm, moist air from Ferrel Cell & the dry air of the Polar Cells

    • Causes extremely variable weather

• Most of North America & Europe

Jet Stream

• Fast-flowing river of air at the boundary between the troposphere and the stratosphere.

• Form where there is a large temperature difference between 2 air masses.

  • This is why the polar jet stream is the most powerful.

• Ionosphere

  • Charged layer from upper mesosphere to exosphere.

Jet Stream- Current location

• Tropopause

• Pole

• Polar Cell

• Polar Jet

• Ferrel Cell

• Hadley Cell

• Equator

Water Properties Cause Wind

• High specific heat

  • Temperature of water changes slowly compared to air

Winds are named from direction they come from

• NW wind

• Sea breeze

• Land breeze

• Mountain breeze

• Valley breeze

• Head wind

• Tailwind

Local Winds

• Between small low and high pressure systems.

• Blow over limited area.

• Local Geography influences these winds.

  • Ocean

  • Lake

  • Mountain

• Can affect the weather & climate for that region.

Land and Sea Breezes

• Ocean water warms slower & cools slower than land

  • Sea cooler than land in daytime

  • Sea cooler than land in summer.

  • Sea warmer than land at nighttime.

  • Sea warmer than land in winter.

• Sea Breeze

  • Blows from Sea to Land

    • Day or in Summer

    • Warm air rises, cool air from over the water flows in to take its place.

• Land Breeze

  • Blow from Land to Sea

    • Warm air over water rises.

    • Cool air from land flows out to take its place.

Air Density

• Warm air less dense

• Cool air more dense

Monsoons

• Large-scale land and sea breezes.

• Seasonal changes in temperature of land and water.

  • Winter

    • Blow from land to water

  • Summer

    • Blow from water to land.

• Important

  • Carry water to the people that live there.

Winter & Summer Monsoon

• Diagram showing wind patterns over Asia.

Mountain and Valley Breezes

• Valley Breeze

  • Air on a mountain slope warms more than the air in valley.

    • Warm air rises and brings up cool air from below.

• Mountain Breeze

  • Night, mountain slope cools more than air over valley.

    • Air flows downhill

Katabatic Winds

• Move much like mountain and valley breezes

• Much stronger

• Form over high plateau surrounded by mountains.

  • In winter plateau is cold

  • Air sinks through the gaps in the mountains

Chinook Winds

• Relatively warm winds.

• Air forced over mountain range

  • Warm air rises over range

  • Global winds pushing over range

  • Air cools as it rises and precipitates.

  • Air now dry, sinks creating a rainshadow effect.

    • Location on the leeward side of the mountain with little precipitation

• Many deserts occur because of this effect.

Chinook Winds

• Description of Chinook winds and adiabatic heating.

• Diagram showing air rising, cooling, and losing moisture on one side of a mountain, then sinking and warming on the other side, leading to the rainshadow effect.

Santa Ana Winds

• Wildfires in Southern California

• Late Fall & Winter

• Great Basin cools creating high pressure zone.

• Temp rises

• Humidity goes down

• Winds blow across desert and race downhill westward toward the ocean.

• Especially fast through Santa Ana Canyon

Desert Winds

• High summer temps create high winds.

• Often associated with Monsoons

• Pick up dust

  • Dust Devil (whirlwinds)

    • Small and short-lived but can cause damage.They occur when hot air rises rapidly, causing dust and debris to be lifted into the air in a rotating column.

Unit 2 - Weather

• Reading: 16.1 - Weather & Atmospheric Water, 16.2 - Changing Weather, 16.3 - Storms, 16.4 - Weather Forecasting

Hurricane Katrina

• Abnormally warm water off of Gulf of Mexico (89 Degrees)

• August 2005

• Started in Bahamas as a Category 1 Hurricane

  • Killing 1 person

  • 600 Million dollars in damage

• Category 5 Hurricane

  • 175 mph winds

  • Gusts 215 mph

  • Evacuation order

Hurricane Katrina Impact

• New Orleans

  • Hit by edge of category 4.

  • Levee collapsed

  • 80% of city under water.

  • 1,300 people died (2,500 people died throughout the region.)

  • 1 million homeless

  • 28 foot waves

  • Looting

  • Over 25,000 animals died

  • Over 100 Billion Dollars in Damage

Chapter 16.1 Lesson Objectives

• Discuss the difference between weather and climate.

• Describe the relationship between air temperature and humidity, including the concept of dew point.

• List the basics of the different cloud types and what they indicate about current and future weather.

• Explain how the different types of precipitation form.

Chapter 16.1 Vocab

• cloud

• dew point

• relative humidity

16.1 - Weather & Atmospheric Water

• Weather is what is going on in that atmosphere at a particular time and place.

• Depends on

  • Air temp.

  • Air pressure

  • Fog

  • Humidity

  • Cloud coverage

  • Precipitation

  • Wind speed & direction

• Energy

16.1 - Humidity

• Water vapor in particular spot.

• Relative Humidity

  • Percentage of water vapor certain amount of air is holding.

• > 100 % water will condense and form precipitation

• Warm air vs. Cold air

• Dew Point

  • Temperature at which air becomes saturated with water.

Humidity Equation

It is 20 degrees C out and there is approximately 15 gram of water in the air per kg of air, what is happening?

Clouds

• Influence on weather

  • Solar Radiation

  • Absorbing warmth from ground

  • Precipitation

  • Insulation

Formation of Clouds

• Air reaches dew point

  • Humidity goes up, Temp. stays constant

  • Humidity remains constant, Temp. drops

    • Lower temps have less ability to hold water vapor.

• @ 100 % humidity droplet form

• Air cools

  • Contact with cold surface

  • Rises

    • Convection

Formation of Clouds Continued

• Rising warm air creates clouds

  • Pushed over mountain range

  • Thrust over a mass of cold, dense air

• Water vapor

  • Only visible once is condenses to a cloud

  • Condenses around a nucleus (dust, smoke, or salt crystal)

  • Billions of the above make a cloud.

Cloud Classification

*4 Cloud Groups (Based on Altitude)

1. High Clouds

   • Cirrus, Cirrostratus, Cirrocumulus

2. Middle Clouds

   • Altocululus, Altostratus

3. Low Clouds

   • Stratus, Stratocumulus, Nimbostratus

Cloud Examples

• Contrails

• Cumulus

• Cumulonimbus

• Cirrocumulus

• Cirrus

• Cirrostratus

• Altostratus

• Nimbostratus

• Stratocumulus

• Fog

• Altocumulus

• Stratus

High Clouds

• Cirrus, Cirrostratus, Cirrocumulus

  • Extremely cold air (Ice crystals)

    • Hold very little water vapor

  • May indicate a storm is coming

  • Sometimes invisible

Middle Clouds

• Altocumulus, Altostratus

• Water droplets and/or ice crystals

• Usually cover entire sky in thick

• Usually indicate a storm is coming

Low Clouds

• Stratus, Stratocumulus, Nimbostratus

• Nearly all water droplets

• Stratus

  • May precede a steady drizzle

• Stratocumulus

  • Rows of large low puffs (white or gray)

  • Rarely bring precipitation

Vertical Clouds

• Prefix Cumulo-

  • Vertically grow instead of horizontally

• Strong air currents rising upward

• Stretch from low to high altitude

• Cumulus

  • White or gray cotton

  • May produce light showers

• Cumulonimbus

  • Vertical air so strong it becomes a thunderstorm

Fog

• Cloud on the ground

• Humid air near the ground cools below its dew point

• Types of fog

  • Radiation fog

    • Clear skies, high relative humidity, ground cools bottom layer,

    • Tule fog is an extreme form

  • Advection fog

    • Warm moist air from the ocean blows over land and cools

    • Bringing fog over land

  • Steam fog

    • Autumn cool air moves over warm lake

    • Water evaporates from lake surface and condenses as it cools

  • Upslope fog

    • Warm humid air up hillside cools below dewpoint

Precipitation

• Dew

  • Moist air cools to dew point on cold surface

• Rain/Snow

  • Clouds

    • Rain/snow droplets grow as currents in cloud collect other droplets

    • Fall when they become heavy enough to escape rising air currents

    • 1 million cloud droplets combine to make one raindrop

Other forms of Precipitation

• Sleet

  • Rain becomes ice as it hits a layer of freezing air near the ground.

• Hail

  • Cumulonimbus clouds with strong updrafts

  • Ice particle continues to form in cloud until it is heavy enough to escape updraft.

  • Stronger updraft = larger hail

Air Rising

As air rises it cools.

16.2 - Changing Weather Lesson Objectives

• Describe the characteristics of air masses and how they get those characteristics.

• Discuss what happens when air masses meet.

• List the differences between stationary, cold, warm, and occluded fronts.

16.2 Vocab

• air mass

• cold front

• front

• occluded front

• squall line

• stationary front

• warm front

Changing Weather

• Dependent upon airmass

• Beneath a front?

• Meeting place between two air masses?

• Characteristics of air mass determine the consistency of the weather.

Air Masses

• Batch of air nearly the same temp and humidity

• Acquires characteristics from land or water below

  • Source Region

• Formation

  • Large area (1,600 \text{ km} across, 1,000 miles)

  • Several km’s thick

  • Typically in high pressure zones

  • Typically in polar in and tropical regions

  • Temperate zones typically are too unstable

Air Mass Symbols

• mT, mP, mE, cT, cP, cAA

• Symbol 1:

  1. C- Origin over a continent

  2. M- Maritime

• Symbol 2:

  1. A- arctic

  2. P- polar

  3. T-tropical

  4. E- equatorial

Air Mass Movement

• Pushed by high level winds

• When moving over a new region it shares humidity & temperature with that region.

• Storms arise when air mass has different characteristics then the region it is moving over.

• Cold air masses tend to flow toward the equator.

• Warm air masses tend to flow toward the poles.

• Nor’ Easter

Fronts

• Two air masses meet at a front

  • Different densities do not mix

  • One air mass is lifted above the other

  • Creating a Low Pressure Zone

  • If moist - condensation & precipitation will form

  • The greater the temp different between air masses the greater the storm

Types of Fronts

• Leading edge gives name to the front

• Four different types of fronts

  • Stationary Front

  • Cold Fronts

  • Warm Fronts

  • Occluded Front

Stationary Front

• Air masses do not move

• Air mass stopped by barrier such as mountain range

• May bring days of rain, drizzle, and fog

• Winds usually blow parallel to the front but in opposite directions

• Likely to break apart after several days.

Cold Fronts

• Cold air mass take the place of a warm air mass

• Advancing Cold Air

• Behind Cold Front

• Cloud Development Because of Frontal Lifting of Warm Moist Air

• Receding Warm Air Ahead of Cold Front

• Direction of Frontal Movement

Squall Line

• Line of severe thunderstorms that form along a cold front

Cold Front Weather by Season

• spring and summer: The air is unstable so thunderstorms or tornadoes may form.

• spring: If the temperature gradient is high, strong winds blow.

• autumn: Strong rains fall over a large area.

• winter: The cold air mass is likely to have formed in the frigid arctic so there are frigid temperatures and heavy snows.

Warm Fronts

• Warm air mass slides over a cold air mass

• Relatively stable atmosphere results

• High cirrus clouds mark the transition from one air mass to the other.

• Cirrus clouds thicken and become cirrostratus

• As the front approaches altocumulous & altostratus clouds appear and turn the sky grey.

• Snow forms and clouds turn to nimbostratus

Occluded Fronts

• Form around low pressure systems.

• Cold front catches up to a warm front.

• Air masses end up back to back.

• Front to back (cold, warm, cold)

• Third to arrive air mass determines the type of occluded front

  • If warm -warm occlusion

  • If cold - cold occlusion

• Fierce weather at the occlusion

• Precipitation & shifting winds

• Frequent at Pacific Coast

16.3 - Storms Lesson Objectives

• Describe how atmospheric circulation patterns cause storms to form and travel.

• Understand the weather patterns that lead to tornadoes, and identify the different types of cyclones.

• Know what causes a hurricane to form, what causes it to disappear, and what sort of damage it can do.

• Know the damage that heat waves and droughts can cause.

16.3 Vocab

• anticyclone

• blizzard

• cyclone

• heat wave

• hurricane

• lake-effect snow

• lightning

• thunder

• thunderstorm

• tornado

• tropical depression

• mid-latitude cyclone

• nor'easter

Thunderstorms

• Warm ground temperature

  • Late afternoon early evening

  • Spring and Summer

• Cumulus to Cumulonimbus

• 40,000 per day

• Water vapor condenses in cloud

  • Latent heat from condensation make cloud warmer than surroundings

• Updrafts to Downdrafts

Stages of a Thunderstorm

• Towering Cumulus Stage

• Mature Stage

• Shutting down the storm

  • Downdrafts cool base of cell

    • No longer have warm air to rise up

  • Storms usually end within 15-30 minutes

  • Other storms may start in the same area

  • Strong storms send strong downdrafts to the ground.

    • These large bursts of air send warm air back up to the cell giving it energy

Air Masses Converge

Maritime tropical from gulf meets continental polar from Canada

Lightening

• So much energy collects in a cumulonimbus cloud lightning forms.

• Requiring electrical discharge

  • Cloud to cloud

  • Cloud to ground

  • Cloud to same cloud

Tornadoes

• Most deaths are from flying debris

• Average of 90 people killed each year

• Form at the front of severe thunderstorms

• April 2011 more than 150 tornadoes in one day!

The Fujita Scale (F Scale) of Tornado Intensity

Tornado Activity in the United States

• Summary of Recorded F3, F4, &FS Tornadoes

• Per 3,700 Square Miles (1950-1998)

Cyclones

• Midlatitude Cyclones

  • Warm air at the cold front rises and creates a low pressure cell.

  • Winds rush into the low pressure and create a rising column of air

  • Air twists due to coriolis effect

  • Rotate counter-clockwise in Northern Hemisphere

  • Nor’ Easters are New England Cyclones

    • About 30 per year

    • Come from the North East

Anticyclone

• Winds rotate clockwise in Northern Hemisphere

Tropical Cyclones - Many Names

• Hurricanes

  • North Atlantic & Eastern Pacific

• Typhoons

  • Western Pacific Ocean

• Tropical Cyclone

  • Indian Ocean

• Willi-Willi’s

  • Near Australia

Tropical Cyclones

• Warm Seas create warm air masses

• Low Pressure forms

  • Tropical Depression

  • Builds to a hurricane in 2-3 days if warm enough water

  • High winds except in the eye

  • Rainfall as high as 1 inch per hour

  • Can also generate tornadoes

Saffir-Simpson Hurricane Scale

Hurricanes

• Move with the prevailing winds.

• When the reach the westerlies they change directions to follow them.

• Storm surge

  • Surge of water causing extreme damage.

• Last 5-10 days

• Cooler water or land ends the hurricane

• Intense rains and tornadoes at the end

Blizzard & Lake-Effect Snow

• Temperatures below –7°C (20°F); –12°C (10°F) for a severe blizzard.

• Winds greater than 56 km/h (35 mph); 72 kmh (45 mph) for a severe blizzard.

• Snow so heavy that visibility is 2/5 km (1/4 mile) or less for at least three hours; near zero visibility for a severe blizzard.

• Blizzards are most common in winter, when the jet stream has traveled south and a cold, northern air mass comes into contact with a warmer, semi-tropical air mass

• Leeward side of a large lake air mass becomes unstable

  • Drops tremendous amount of snow

Heat Wave

• 3 or more days of 86 degrees Fahrenheit or greater

• Deadly heat