3/18/15

AIM: How does solar heating and water vapor in the atmosphere affect weather?

DO NOW: How does weather affect your life?

HOMEWORK: Finish all Vocabulary P.454 Figure 1“Identifying” P. 455 figure 2 “infer” P 456 “Reading check”

3/19/15

AIM: How does solar heating and water vapor in the atmosphere affect weather?

DO NOW: What factors affect the weather?

HOMEWORK p.461 # 1-5

3/23 AIM: How can clouds help us determine the weather?

Do Now: Describe the type and shape of clouds on a rainy day and on a sunny day

HOMEWORK: “Types of clouds” handout

What am I?

You can’t see me, but you feel me, you can’t touch me, but I can touch you. I have been called the “Breathe of the Gods”, or the killer and giver of life, gentle and fierce, friendly and enemy, angry and happy.

What am I?WIND

Weather is....

The current state of the atmosphere...what is happening right now

The sun provides the energy that drives the Earth’s weather

Main points to remember as we learn about weather:

The sun warms the earth’s surface and therefore all the air above the surface

The earth is warmed most at the equator and least at the poles---why?

The air above land is warmed more quickly than air above water.

Warm air expands and rises, creating an area of low pressure; cold air is dense and sinks, creating an area of high pressure

Weather Factors

FACTORS• TEMPERATURE= the average motion of

molecules↑ TEMP= ↑movement of molecules= feels

hot

↓ TEMP= ↓movement of molecules= feels cold

Air Pressure

Warm air= expanding or rising air= leaves behind Low pressure

Cold Air =sinking air= leaves an area of High pressure

Humidity and Relative Humidity and Relative HumidityHumidity

The amount of water vapor present The amount of water vapor present in the airin the air

Relative HumidityRelative Humidity -is a measure of -is a measure of the amount of water vapor present in the amount of water vapor present in the air compared to the amount the air compared to the amount needed for saturation at a specific needed for saturation at a specific temperaturetemperature

Fig.4 page 457Fig.4 page 457

Water in the Atmosphere: Water in the Atmosphere: Humidity Humidity (detailed)(detailed)

HumidityHumidity: : measure of the amount of measure of the amount of water vapor stuck between molecules in water vapor stuck between molecules in the air. The air’s ability to hold water the air. The air’s ability to hold water depends on the air tempdepends on the air temp

The hotter the air, the more water The hotter the air, the more water the air can holdthe air can hold

Cold airCold air: molecules move slower so droplets : molecules move slower so droplets of water can start to stick of water can start to stick together=condensationtogether=condensation

Relative humidityRelative humidity: the amount of water : the amount of water vapor(%) compared to the amount the air can vapor(%) compared to the amount the air can hold- tool used is a hold- tool used is a psychrometer.psychrometer.

100%=air is saturated100%=air is saturated

Relative humidityRelative humidity

If you hear a weather forecaster If you hear a weather forecaster say that the relative humidity is say that the relative humidity is 50% it means=50% it means=

The air contains 50% of the water The air contains 50% of the water needed for the air to be saturatedneeded for the air to be saturated

DEW POINT

The temperature at which air is saturated and condensation forms

Changes with the amount of water vapor in the air

When air near the ground cools to its dew point, water vapor condenses and forms dew

APPLYING MATH p457

WIND

Why can you fly a kite on some days but not others?

Kites fly because air is moving from regions of high pressure to low pressure

Warm air is less dense and expands causing low atmospheric pressure.

Cool air is more dense and has higher atmospheric pressure

WindWind Air moving in a Air moving in a

specific directionspecific direction Warm, Warm, expanding air expanding air

has low atmospheric has low atmospheric pressurepressure

CoolCool air is dense, air is dense, sinks and has high sinks and has high atmospheric pressure atmospheric pressure

Wind resultsWind results

because air moves from because air moves from areas of high to low areas of high to low pressure pressure

HOW TO MEASURE WIND DIRECTION AND SPEED

Wind Direction Wind vane (has an arrow that points in

the direction from which the wind is blowing)

Wind sock= has one open end that catches the wind causing the sock to point in the direction from which wind is blowing

Wind speed= measured using an anemometers ( rotating cuffs that spin faster when the wind is strong)

REVIEW: What causes winds?

A wind is a A wind is a horizontal horizontal movement of air movement of air from a area of from a area of high pressure to high pressure to an area of low an area of low pressurepressure

It is this It is this difference in difference in pressure that pressure that makes the air makes the air move=windmove=wind

Winds are measured by direction and speed

The anemometer is the tool we use to measure this

Wind chill=↑ cooling the wind causes

Review ch. 15 Review ch. 15 Local WindsLocal Winds The land cools and heats faster than the

ocean. Water holds heat longer than land, and takes longer to heat or cool.

SEA BREEZE During the day, the land gets hotter faster than the water. The heated air rises, leaving behind an area of low pressure. Wind from the cooler sea blows in to take the place of that warmer air. These happen during the day!

Review ch 15Review ch 15LandLand BreezesBreezes At night the lands cools off faster

than the sea. Cool air sinks creating an area of high pressure. Wind blows from the land to the sea.

Cloud Formation

Form when warm air is forced upward, expands and cools

Clouds form when water vapor condenses on particles (dust, salt, etc) in the air (RELATIVE HUMIDITY IS 100%)

The temperature in which condensation begins is called the dew point

CloudsClouds Masses of small water droplets or tiny Masses of small water droplets or tiny

ice crystals that float in the air.ice crystals that float in the air. Why don’t clouds fall??Why don’t clouds fall?? Clouds are classified by their Clouds are classified by their shapeshape

and and height height (vary with temp., pressure, (vary with temp., pressure, and water vapor in the atmosphereand water vapor in the atmosphere

SHAPE OF CLOUDSSHAPE OF CLOUDS

3 main 3 main types are types are cirrus, cumulus, and stratus.cirrus, cumulus, and stratus. LATIN ROOTSLATIN ROOTS- Cirus - Cirus comes from the word meaning comes from the word meaning “lock of “lock of

hair”hair”- - CumulusCumulus come from the word meaning come from the word meaning “heap”“heap”- Stratus Stratus comes from the word meaning comes from the word meaning layerlayer- Nimbus Nimbus come from the word meaning come from the word meaning “rain “rain

bearing”bearing” Other clouds are a mixture of these three main Other clouds are a mixture of these three main

types.types.

TYPES OF CLOUDS

Cirrus Clouds: wispy, feathery clouds

CirroCirro- means “curled” or - means “curled” or “feathery”“feathery”

-comes from a word meaning “lock of hair”

**Form only at high levels, therefore are made of ice crystals

-Usually signal of a clear day

Types of Clouds Cumulus Clouds: are puffy white cotton ball looking clouds CumuloCumulo- means “heaped” or “piled”- means “heaped” or “piled”

***Usually signal good weather, ***Usually signal good weather, but if but if the atmosphere is unstable,the atmosphere is unstable, can build can build into towering clouds that produce into towering clouds that produce showers and thunderstorms.showers and thunderstorms.

Cumulonimbus Clouds

These are thunderstorm clouds NIMBUS= rain

Stratus Clouds

Stratus Clouds: clouds that form in flat layers- cover all or most of the sky and are low level clouds

When air is cooled to its dew point near the ground it forms a status cloud called FOG

Clouds classified by height=

Cirro- high clouds Alto=middle elevation clouds Strato= low elevation

Ex. Cirrostratus-> made of ice crystals and form high in the Earths atmosphere

Ex. Altostratus-> form in middle layers

Rain or Snow??

- Clouds associated with rain or snow usually have the word “nimbus” (Latin for dark rain cloud) attached to them

CUMULONIMBUS-when a cumulus cloud grows into a thunder storm

Nimbostratus-layered clouds that can bring long, steady rain or snow

Other Cloud TypesOther Cloud Types

Cirrocumulus Cirrostratus

Stratocumulus Cumulonimbus

More Cloud TypesMore Cloud Types

Altocumulus

Altostratus

Nimbostratus

PrecipitationPrecipitation

Water that falls from the cloudsWater that falls from the clouds Air temperature determines the form of Air temperature determines the form of

precipitation that fallsprecipitation that falls 4 main 4 main types of Precipitation: types of Precipitation: Rain, Sleet, Snow Rain, Sleet, Snow and and Hail= Hail=

-precipitation in the form of lumps of ice-precipitation in the form of lumps of ice

-HAIL forms in cumulonimbus clouds of -HAIL forms in cumulonimbus clouds of thunderstorms when water freezesthunderstorms when water freezes

Types ofTypes of PrecipitationPrecipitation

RainRain SleetSleet

SnoSnoww

HailHail

WEATHER PATTERNSWEATHER PATTERNSSECTION 2SECTION 2

AIM: How is weather associated with fronts AIM: How is weather associated with fronts and low and high pressure?and low and high pressure?

DO NOW: How can we use clouds as an DO NOW: How can we use clouds as an indicator of severe weatherindicator of severe weather

Homework: Homework: Page 463 Reading checkPage 463 Reading check

-Page 464 Figure 11 , DESCRIBE: What type of weather -Page 464 Figure 11 , DESCRIBE: What type of weather occurs at front boundariesoccurs at front boundaries

-Page 465 Figure 12- IDENTIFY some things that tall -Page 465 Figure 12- IDENTIFY some things that tall cumulonimbus clouds producecumulonimbus clouds produce

Air MassesAir Masses

A large body of air that A large body of air that has properties similar to has properties similar to the part of the Earth’s the part of the Earth’s surface over which it surface over which it develops. develops.

Example: an air mass that develops over land is dry compared to one that develops over water

If developed in the tropics it is warmer than that which developed over colder regions

Air Masses

Air Mass MapAir Mass Map

HIGHS AND LOWSHIGHS AND LOWS

Pressure Systems -descending (going down)=H

pressure -ascending (going up)=L pressure

Weather Foldable

Warm front Cold front Occluded front Stationary Front

Fronts: the boundary between 2 air masses

Warm Front: warm air slides over departing cold air- large bands of precipitation form

This is the symbol on a map for a warm front

Cold Fronts

Cold air pushes under a warm air mass. Warm air rises quickly=narrow bands of violent storms form

This is the symbol for a cold front

Occluded Front

2 air masses merge and force warm air between them to rise quickly. Strong winds and heavy precipitation will occur

This is the weather map symbol for an occluded front

Stationary Front

Warm or cold front stops moving. Light wind and precipitation may occur across the front boundary

This is the weather map symbol for a stationary front

Reading a weather map

ISOBAR= connects areas of equal pressure BAR comes from BARometric pressure

Reading a weather map...

Isotherm: Connects areas of equal temperature; therm means temperature

Weather Station (not on the TV)