MeteorologyMeteorology

Meteorology

Branch of the natural sciences that deals with the Earth’s atmosphere & its related phenomena.

Listening to the chirps of crickets can give you a rough estimate of what the temperature outdoors is on the Fahrenheit temperature scale. Count the amount of chirps you hear in fifteen seconds and add 37

The 4 Factors that Cause Weather:

• Temperature

• Air Pressure

• Wind

• Moisture

Earth’s Atmosphere:

79% Nitrogen

20% Oxygen

1% Everything Else

Variable Components Water Vapor Aerosols--suspended solid

& liquid particles in the atmosphere

Ozone--(O3) absorbs harmful UV radiation

The Atmospheric CompositionThe Atmospheric Composition

Death Valley, California's temperature has the U.S. temperature record: 134 degrees Fahrenheit 

Troposphere - bottom layer where we live. * Weather occurs here.* Gets colder w/ altitude.Stratosphere—2nd layer* Contains the Jet Stream & Ozone layer* Gets warmer w/ altitude.Mesosphere—3rd layer* Gets colder w/ altitude.Thermosphere– 4th layer* Ionosphere-lower part, made of charged ions.* Exosphere-upper part, satellites orbit at this location.* Van Allen Radiation Belts-layers of high radiation that help block solar particles.

Atmospheric LayersAtmospheric Layers

Troposphere

Stratosphere

Mesosphere

Thermosphere

Ionosphere

Exosphere

OzoneLayer

Unequal Heating of the EarthDirect Sunlight Energy (comes at a 90º

angle) causes more HEAT. It occurs most often at the equator.

Indirect Sunlight Energy (comes in at an angle less than 90º) doesn’t produce as much heat.

Heating of the EarthHeating of the Earth

Prospect Creek, Alaska holds the U.S. temperature record for the coldest temperature: minus 80 degrees Fahrenheit

Radiation– Sun gives off light energy because of nuclear

fusion. (Fusing of 4 hydrogen atoms into a single helium atom)

– Atmosphere absorbs most of the radiation.– Ground absorbs the rest.

Heat TransferHeat Transfer

The hot and cold temperature extremes ever recorded on earth is over 260 degrees Fahrenheit

Conduction--the direct transfer of heat energy from one substance to another.

**The warmth of the Earth’s surface slightly warms the air that it comes in contact with.

ConvectionConvection--the transfer of heat energy --the transfer of heat energy in a gas or liquidin a gas or liquid

**Warm air rises, cold air sinks**Warm air rises, cold air sinks

““Greenhouse Effect”Greenhouse Effect”-- CO-- CO2 2 collects in the collects in the

atmosphere & traps heat energy at the atmosphere & traps heat energy at the surface. (COsurface. (CO22 is 0.036%) is 0.036%)

Air has mass, so its weight (gravity) pushes down on the earth causing pressure.Movement of Air •Warm air expands, making it less dense so it rises causing LOW pressure. Warm air holds more moisture.•Colder air contracts, making it more dense so it sinks causing HIGH pressure. Cold air holds less moisture.•LOW Pressure is usually associated w/ cloudy, rainy weather.

Air PressureAir Pressure

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HIGH Pressure is usually associated w/ good/fair weather.

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Every winter around one septillion snowflakes fall from the sky! That's a one with 24 zeros following it

Measuring Pressure• Barometer (Mercury or Aneroid) measures

the change in air pressure in either millibars or millimeters/inches of mercury.

Windthe movement of air from one place to anotherAir moves from a HIGH pressure to LOW pressure.

Global Winds Created by the unequal heating of the Earth’s surface,

difference in air pressure& the Earth’s rotation.Coriolis Effect--due to the Earth’s rotation, moving objects

such as air and water will shift in a certain direction.

Northern Hemisphere = rightNorthern Hemisphere = right

Southern Hemisphere = leftSouthern Hemisphere = left

Hilo, Hawaii is the wettest city in the United States with an average annual precipitation of 128 inches! To put that into perspective, one inch of rain falling over one acre of land is over 27,000 gallons of water or over 226,000 pounds of water.

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Global Wind Belts Trade Winds – winds

that blow from east to west on either side of the equator. Separated by the Doldrums

Prevailing Westerlies – winds that blow from west to east between 30o & 60o north & south latitudes.

Polar Easterlies - winds that blow from east to west in the polar regions.

Jet Stream

• A narrow stream of high pressure wind found in the lower stratosphere.

• Pushes large air masses across the globe.

Contrary to popular belief, lightning does strike twice in the same place. Tall buildings such as the Sears Tower in Chicago are struck repeatedly.

Measuring Wind

Wind Speed—Anemometer

Wind Direction--Wind Vane

Measured in mi/hr, km/hr, and knots.

A light wind is called a "zephyr." Many poets use the term to describe the gentlest of breezes.

MoistureHumidity

The measure of the amount of water vapor in the atmosphere.

Specific Humidity--measure of the actual mass of water vapor in a given mass of air.

Relative Humidity--ratio/percentage of the actual amount of water vapor in a given mass of air compared to the maximum amount of water vapor that air can hold at a given temperature.

Psychrometer--a type of hygrometer that has a wet bulb thermometer & a dry bulb thermometer

Dew Point Temperature--the temperature to which air has to be cooled in order to be completely saturated (filled) with water.

Clouds•Suspended droplets of water that collect on aerosols.

•Formation of clouds depend on the amount of moisture & aerosols in the air, the air temperature, & the stability of the air (air pressure.)

A lightning bolt travels up to 60,000 miles per second and can reach temperatures as high as 50,000 degrees Fahrenheit.

Cirrus – high clouds that are thin & wispy. Made of ice crystals.

Stratus – low level clouds that have a layered look.

Cirrus

Stratus

Florida has the highest instance of lightning fatalies; however, over 8,300 people have been killed by lightning from 1940 to 1991 in the United States. 

Cumulus – large, fluffy clouds of vertical development.

The prefix alto- is added to the name of clouds formed in the middle cloud layer.

Cumulus

Altocumulus

Bad family genes? A woman gets struck by lightning in 1995. Three weeks prior her nephew was struck and suffered temporary blindness. Years before in 1970 her cousin was zapped when lighting hit her umbrella, but this wasn't the first time, she was also struck once before in 1965. Her grandfather was killed by lightning in 1921 and his brother struck and killed in the 1920's

The prefix/suffix nimbus- is added to the name of a cloud that produces precipitation.

Cumulonimbus

Nimbostratus The best chance to be fatally struck by lightning is before you see the storm as lightning can travel horizontally over six miles

PrecipitationRain

Hailstones–Form in cumulonimbus clouds–Strong winds carry rain drops above the freezing line.

–Rain drops freeze into ice pellets & fall.–Stronger the wind, the larger the hailstone.

Freezing Line

The largest hail stone ever discovered was found in Nebraska and its circumference was that of a soccer ball!

The hail stone that holds the record for the heaviest recorded in the USA, was found in Coffeyville, Kansas, on September 3, 1970. Weighing in at 0.75 kilograms (1.67 pounds) it had a diameter of 14.4 centimeters (5.67 inches), a circumference of 44.5 centimeters (17.5 inches). 

Sleet•Rain freezes into an ice pellet as it falls through a pocket of freezing air.

Freezing Rain•Rain falls to the ground and freezes on contact with the surface.

The largest tornado in the United States was around two and a half miles wide. It happened in Nebraska in 2004. Although tornados have been reported worldwide, most happen in the United States

SnowThis occurs when cloud droplets freeze in the clouds and stick together forming flakes.

Air Massesa large body of air that is the SAME throughout

Types

**Named based on where the air formed, its temperature, and its humidity

Maritime Polar--it forms over the Northern Atlantic and Pacific Oceans.

*Brings COLD, MOIST air

Maritime Tropical--it forms near the equator. It brings WARM, MOIST air.

*If it comes in contact with cooler air from the North, storms will form.

Continental Polar--it forms over northern Canada. It brings COLD, DRY air.

*Causes extremely cold temperatures in the United States.

Continental Tropical--it forms over land in Mexico. It brings HOT, DRY air.

The Enhanced Fujita Tornado scale measures wind speeds of tornados from EF0 to an EF5. The tornado that wiped out the center of Greensburg, Kansas measured EF5. Only 51 EF5 tornadoes have been recorded since 1953 and just two since 2007. The wind speed of an EF5 tornado is over 200 miles per hour

Fronts• The boundary where two air

masses collide.

• The front is named for the aggressive air mass.Cold Front

Cold air meets and replaces a mass of warm air.

Fast in speed.Form cumulus clouds.Narrow frontal zoneShort, severe weather

Cold Front Symbol

Warm FrontWarm air mass overtakes and moves over a cold

air mass. Slow moving Forms stratus clouds Wide frontal zone Long periods of drizzle Overcast skies

Warm Air

Cold Air

Warm Front SymbolTexas gets about 110 tornadoes each year, the most of any U.S. state.

Stationary Front--neither air mass moves

* No bad weather

Occluded Front--a cold front catches up with a warm front and overtakes it

* Weather can be variable and the conditions can change.

Stationary Front Symbol

Occluded Front Symbol Cold Warm

Cooler

• What could be happening in this comic?• Should they seek shelter?

Dry LineDry air invades moist air. Fast moving Narrow frontal zone Forms cumulus clouds Severe weather in

most cases

Moist Air

Dry Air

Dry Line Symbol

Hurricane Katrina was a category four hurricane that hit the southern coastline of the United States in 2005. Hurricane Camille, a category five hit the same area less than forty years earlier.

Severe Weather• Weather that can be considered life

threatening and can cause damage to buildings

• Includes thunderstorms, lightning, tornadoes, flooding, hurricanes, etc.

Hurricanes are called hurricanes if they develop in the Atlantic Ocean. If they develop in the Pacific Ocean, they are called typhoons.

Watches and WarningsWatches – a watch is issued when the

conditions for a certain type of severe weather are possible, but not necessarily occurring at the moment.

Warnings – a warning is issued in a specific area where a type of severe weather is occurring at that given moment.

The worst hurricane in U.S. history happened in 1900 in Galveston, Texas, where 8,000 people died

ThunderstormsFast moving rainstorms that can

produce strong winds, hail, heavy rainfall, lightning & tornadoes.

Lightning – static electricity caused by the separation of electrical charges by the collisions of rain drops & strong winds.

The positive & negative charges seek each other out. When they connect, an electrical discharge occurs creating a lightning bolt.

• Thunder – the heat generated by the lightning bolt superheats the surrounding air causing it to expand so rapidly that it causes a sonic boom.

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BOOM!

Hurricane Andrew cost Florida and Louisiana over $26 billion in 1992. A category five, it was the costliest hurricane in U.S. history.

• Bolts of lightning can travel as far as 25 miles or more.• Lightning kills an average of 55 people in the United States

each year.• The only two safe places to be during a thunderstorm are in a

car or in an enclosed house that has electricity and plumbing.• They can strike on a clear day• "If you feel a tingling sensation, your hair stands on end or you hear

'buzzing' from nearby rocks, fences, etc., move immediately. Lightning may be about to strike!“

• Britney Wehrle was walking with a friend on a sunny, warm day when she was suddenly struck by lightning, even though the sky above her was clear and blue.

MONTEVIDEO, Uruguay -- Lightning struck only once - but 52 cows are dead at an Uruguayan ranch. The newspaper El Pais reports that the cows had pressed against a wire fence during a storm when the lightning bolt struck in the northern state of San Jose.

• Lightning scars

What you wear (sneakers, rubber boots, hairpins, cleats, etc.) can increase or decrease your chances of being struck by lightning.

Fact or Fiction?

Fiction. What studies have been done indicate that what you wear doesn’t make much difference either way.

 You’re safe from lightning inside a car because the rubber tires act as insulators.

Fact and Fiction. You are safe from lightning in a car if it has a metal top and sides and if the doors and windows are shut tight. Don’t touch the car frame, steering wheel, ignition, gear shift, or radio. The metal shell of the car conducts the electricity away and that protects you, not the tires.

Carrying an umbrella can be dangerous when lightning is present.

Fact. Anything that makes you taller increases your risk.

If lightning only hits the ground close by, you’re safe.

Fiction. When lightning hits the ground, the current spreads along the surface to a depth of a few inches. Any fence or pipe in its path will be charged with energy for quite a distance. Any person in its path can be injured.

Fact. If lightning strikes your home, the charge travels through power lines, phone lines, and plumbing until it reaches the ground. If you’re in the bath or shower, touching an electric appliance, or on a corded phone, you could be injured.

Lightning travels down telephone wires.

Tornadoes

• Funnels of high speed circulating winds

• High winds & updrafts collide creating a circulating low pressure.

• The cloud begins to lower below the cloud base (wall cloud.)

• The low pressure extends to the ground picking up dust & debris forming a tornado.

The hottest recorded temperature on Earth was 136 degrees in El Azizia, Libya, in 1922

Joplin, Mo. before and after the massive, deadly tornado

Hurricanes

• Tropical cyclone that has a low pressure center (eye) with several rotating thunderstorms & strong winds around it.

• Start as tropical depressions over warm water in the oceans. Storm builds strength as it travels over the warm water.

Flooding

• Kills more people in the U.S. than any other type of severe weather.

• Caused by too much rain over an extended period of time. It causes lakes, streams, rivers, etc. to overflow.

Flash Flooding• Flooding that mainly occurs in towns or cities.

• A rainstorm that dumps several inches of rain over a short period of time causes it.

• It is too much for the ground to soak up.

• It causes low lying areas to overflow and rushing water in other areas.

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