Cheektowaga Central School District



NOTE PACKET # 8

“WEATHER”

NAME; EARTH SCIENCE

PERIOD;

1) Atmospheric Temperature

weather -

Weather variables are used to describe the condition of the

atmosphere (the weather).

On a weather map, weather variables are shown with a station model

Examples of weather variables include;

1) 5)

2) 6)

3) 7)

4)

Most of the weather changes occur in the .

Weather is caused by…..

Variations in insolation cause

Heat energy tends to move toward

The movement of heat energy results in

ATMOSPHERIC TEMPERATURE

Temperature conversions; Celsius, Fahrenheit, Kelvin scales (see Earth Science Reference Tables).

Air temperature is usually measured using a

[pic] [pic]

Temperature is modeled on maps and charts by the use of lines called

.

Heating of the Atmosphere

The is the original source of almost all the heat in

the atmosphere.

5 ways in which the atmosphere is heated.

1)

2)

3)

4)

5)

Convectional Transfer of Heat in the Atmosphere

Heat energy is transferred within the atmosphere by

Differences in air pressure cause air to move in circular patterns called

.

Wind is

Heating of Air by Compression &

Cooling of Air by Expansion.

When a gas expands…

example ; , .

When a gas is compressed….

Within the troposphere…..

As air rises

*

*

*

As air descends…

*

*

*

Draw Diagram;

Under average conditions air temperature in the troposphere…

See Earth Science Reference Tables;

2) Atmospheric Pressure & Density

The denser the atmosphere…..

atmospheric pressure

➢ a.k.a.; or .

➢ .

diagram.

Measurement of and Changes in Air Pressure.

The instrument that is used to measure air pressure is a

Types of barometers.

[pic] [pic]

Mercury barometer Aneroid Barometer

Air Pressure is measured in either.

1)

2)

To convert from millibars to inches of mercury use the Earth Science Reference Tables, page 13.

Examples;

1) 976.0 mb =

2) 1001.0 mb =

3) 30.00 inches =

4) 29.09 inches =

Lines drawn on a weather map that connect locations that have the same barometric pressure are

called .

The weather map below shows surface air-pressure readings, in millibars, at various locations in the United States and Canada. The 1020-millibar isobars have been drawn and labeled.

Draw the 1024- and 1028-millibar isobars on the weather map.

[pic]

The Effect of Temperature on Air Pressure.

As the temperature of the air increases,

example;

The Effect of Water Vapor on Air Pressure.

The greater the amount of water vapor in the air,

molecular weight water molecular weight of air

nitrogen oxygen

H2O N2 O2

One molecule of water

Effect of Altitude on Atmospheric Pressure.

As altitude or elevation increases,

diagram;

SUMMARY

As either

3) WIND

wind –

Wind Speed

Winds are caused by

➢ air moves from towards .

Differences in air pressure are caused by…

1)

2)

Air pressure gradient

air pressure gradient -

The closer together the isobars on a weather map are…

The greater the pressure gradient,

diagram:

anemometer -

Land Breeze vs Sea Breeze

diagram; Land Breeze

diagram; Sea Breeze

Wind Direction

Wind moves from areas of

Coriolis effect

➢ (caused by )

➢ deflects winds to the

➢ deflects winds to the

A wind is named for the direction

wind vane -

4) CIRCULATION OF AIR IN THE

TROPOSPHERE

Convection Cells

The unequal distribution of insolation on Earth results in….

➢

➢

Cooler air,

Warmer air,

➢ Air rises at (the ) and

North and South Latitudes.

➢ Air sinks near and North and South Latitudes.

➢ Regions where

➢ Regions where

jet stream -

➢

Planetary Wind and Pressure & Moisture Belts

See ESRT

Remember……

➢

➢

➢

prevailing winds – within the planetary wind belts,

Seasonal Shifting of the Wind and Pressure Belts

Wind and pressure belts shift…..

➢ ( )

➢ ( )

Weather Movement in the Contiguous United States.

The US is affected by planetary winds that blow from the

Weather generally moves .

Formation of Surface Ocean Currents

see ESRT; page 4 "Surface Ocean Currents".

Surface ocean currents are caused

Direction of currents is affected by

8-5) ATMOSPHERIC MOISTURE

➢ Gaseous water in the atmosphere is called

➢ % of Earth’s surface is covered by water.

Water enters the atmosphere by;

1 –

2 –

3 –

is the process by which liquid changes to a gas.

is the process by which plants release water vapor as part of their life functions.

evapotranspiration = and

Energy of Evaporation and Transpiration of Water

Almost all the energy for evaporation and transpiration comes from

.

When evaporation or transpiration occurs…..

➢

➢

➢

THEREFORE, EVAPORATION IS A PROCESS.

The Process of Evaporation

4 Factors that Affect the Rate of Evaporation

1)

➢ the higher the temperature, .

2)

➢ the greater the surface area, .

3)

➢ the drier the air, .

4)

➢ the greater the wind speed, .

Humidity, Temperature, and Dew Point

humidity –

absolute humidity -

The warmer the air .

relative humidity -

( ).

Relative Humidity and Temperature

If more water vapor is added to the air …..

➢ relative humidity .

➢ absolute humidity .

If temperature increases…..

➢ relative humidity

➢ absolute humidity

If temperature decreases,

➢ relative humidity

➢ absolute humidity

Dew Point

dew point -

➢ the temperature at which humidity = %.

It is the temperature at which water vapor will

When the air temperature reaches the dew point….

As the amount of water vapor in the air increases,

draw diagram.

HUMIDITY

➢

➢

➢

➢

Measuring Relative Humidity

psychrometer -

Wet bulb / Dry bulb

➢ since evaporation is a ….

➢ The amount of cooling depends on the

➢ If the air is saturated, …..

the wet bulb and dry bulb temp will be .

➢ The drier the air, the ….

.

Determining Relative Humidity and Dew Point

Use the diagram on page 12 of the Earth Science Reference Tables and the data below, to calculate the relative humidity.

Dry Bulb Wet Bulb Difference Relative Humidity

1) 28 16

2) 20 12

3) 12 7

4) 2 1

5) -10 -10

Use the diagram on page 12 of the Earth Science Reference Tables and the data below, to calculate the Dew Point.

Dry Bulb Wet Bulb Difference Dew Point temp

1) 28 16

2) 20 12

3) 12 7

4) 2 1

5) -10 -10

Precipitation

precipitation -

rain gauge -

Snow depth

Cloud Formation

➢ Need and

condensation nuclei ( ; , )

➢

Steps for cloud formation.

Warm air .

As air rises, pressure , the air

and the temperature of the air .

When the air temperature = the ,

the air becomes and water

on the .

cloud –

➢ If a cloud is on, or just above, Earth's surface, it is called

8-6) AIR MASSES AND FRONTS

air mass –

➢

Characteristics of Air Masses

An air mass forms when

➢

If the air mass forms…..

Over water = symbol = ( )

Over land = symbol = ( )

Near the Equator = symbol = ( )

Near the Pole = symbol = ( )

See symbols on Earth Science Reference Tables p. ,13

[pic]

Air Mass Worksheet

Lows and Highs

The troposphere is divided into two portions according to ….

1)

2)

Low ( )

➢

➢

➢

➢

Highs ( )

➢

➢

➢

➢

Fronts

front - (or )

➢

4 Types of Fronts

1 - Cold Front

➢

➢

diagram symbol

2 - Warm Front

➢

➢

diagram symbol

3 - Occluded Front

➢

symbol

4 - Stationary Front

➢

diagram symbol

Symbols for Fronts (see ESRT)

On the satellite image, draw the proper symbol to represent the most probable front on line XY.

Which type of front is located between Buffalo and Detroit?

(1) stationary (3) occluded

(2) warm (4) cold

Which cross section best represents the fronts and air movements in the lower atmosphere along line XY?

[pic][pic][pic][pic]

(1) (2) (3) (4)

Tracks of Air Masses and Fronts

➢

If a low-pressure system follows a typical storm track across New York State, it will move toward the...

(1) southeast (2) northeast (3) southwest (4) northwest

8-7) Storms and Severe Weather

storm

*

* usually associated with;

Mid-latitude or Cyclonic Storms

*

polar fronts

*

* mid-latitude storms develop when

* may produce

Hurricanes

* begin as

usually occur in

the lower the air pressure,

* once sustained winds reach

* the center of the hurricane is called

* the hurricane loses energy when

(

)

* hurricanes originally move

* however, once they begin to (

)

* most deaths are caused by ;

and

* storm surge –

Base your answers on the satellite image below, which shows a Northern Hemisphere hurricane.

What is the usual surface wind pattern around the eye of Northern Hemisphere hurricanes?

(1) clockwise and outward

(2) counterclockwise and outward

(3) clockwise and inward

(4) counterclockwise and inward

Which air mass is normally associated with the formation of hurricanes?

(1) continental tropical (3) continental polar

(2) maritime tropical (4) maritime polar

Clouds form in the hurricane because the air is

(1) sinking, expanding, and cooling (3) rising, expanding, and cooling

(2) sinking, compressing, and warming (4) rising, compressing, and warming

When the eye of this hurricane reaches 43° N latitude, this hurricane will most likely be pushed by planetary winds toward the

(1) northwest (3) southwest

(2) northeast (4) southeast

Thunderstorms

*

*

*

Tornadoes

*

usually last

maximum calculated wind speed = mph.

* form along

* safety;

Base your answers on the map, which shows a portion of the United States where 148 tornadoes occurred during a 24-hour period in April 1974. The paths of the tornadoes are shown.

Explain why all the tornadoes moved toward the northeast.

Describe the air movement most likely found within these tornadoes.

A school receives a tornado warning. Describe one emergency action that a teacher and the students in a classroom should immediately take to protect themselves from injury.

Most of these tornadoes occurred with thunderstorms along cold fronts. Identify the water cycle process that forms clouds along cold fronts.

Blizzards

*

Lake Effect Snow

Need;

*

*

*

Which New York State location is most likely to experience the heaviest winter snowfall when the surface winds are blowing from the west or northwest?

(1) New York City (3) Oswego

(2) Binghamton (4) Plattsburgh

Emergency Preparedness (refer to handout!)

8-8) Weather Prediction and Probability

Relationships between weather variables.

1) As temperature increases air pressure

2) As the temperature gets closer to the dew point, the chance of

precipitation

3) As the difference between air temperature and the dew point temperature becomes smaller, the relative humidity (

)

4) As the air pressure gradient increases, wind speed

5) Rapidly falling air pressure =

Weather Maps and Station Models.

[pic]

Which station model correctly represents the weather conditions in an area that is experiencing winds from the northeast at 25 knots and has had a steady drop in barometric pressure of 2.7 millibars during the last three hours?

[pic] [pic] [pic] [pic]

(1) (2) (3) (4)

The diagram below shows conditions that commonly cause fog to form over land in coastal areas.

A weather station at the lighthouse records a temperature of 36°F and an air pressure of 1016.4 mb. Using the proper weather map symbols, place the following information in the correct positions on the weather station model.

• Present weather

• Dewpoint

• Air pressure

• Wind direction

• Wind speed

Base your answers on the station model below, which shows the weather conditions at Rochester, New York, at 4 p.m. on a particular day in June.

What was the actual barometric pressure, according to the station model, to the

nearest tenth of a millibar?

The winds shown by this station model were blowing from which compass direction and at what wind speed?

direction =

speed =

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