Unit Two / Chapter 4 Weather and Climate - Wikispaces04+Notes.pdfUnit Two / Chapter 4 Weather and Climate Page 1 of 13 A scension Collegiate

Unit Two / Chapter 4 Weather and ClimatePage 1 of 13

Ascension Collegiate World Geography 3202

Chapter 4Pages.....54.....73

Weather And ClimateCHAPTER OUTLINE

Introduction

A. The earth-sun Relationship(A-1) Sunlight and Clouds

B. Patterns in TemperatureC. Wind: The Movement of Air

(C-1) Prevailing Winds(C-2) Wind and Precipitation Patterns

D. Other Factors Affecting Climate(D-1) Ocean Currents and Climate(D-2) Continentality and Climate(D-3) Elevation and Climate

Introduction:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pg54

- Weather: The day to day or short-term conditions of the atmosphereThe daily atmospheric conditions in a given place over a short period of time

- Weather: Atmospheric conditions which are constantly changing - Temperatures can be blistering hot or bone-chillingly cold- Totally dry or heavy rain- Days and nights can be calm and still or have violent winds

- Weather: Includes such variables as temperature, precipitation, humidity, cloud cover, wind, and air pressure.

- Weather: The forecast for today is....................

- Climate: Also includes such variables as temperature, moisture, and air movement.

- Climate Time is a key factorClimate is the average of the weather conditions in a given place

for a long period of time.Text says .............general patterns of temperature, moisture and airmovement in a region over the course of many decades.



- â NoteIn some places weather conditions seldom change so there are

“no” distinct seasons. (Equatorial or polar areas are possible examples). Other places weather may vary throughout the year creating distinct

seasons (Southern Canada) - ã Note:

Although weather patterns for an area may be well established, the weather on a particular day or week can fall outside the established climatic range.

Questions.....Page 55.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 1, 2, 3,4, 5

A. The Earth - Sun Relationship. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pg 55

- The sun provides light and heat for all bodies of the solar system.- The sun is approximately 150,000,000 km away from earth.- It is 109 times Earth’s diameter.- At the sun’s core it is approximately 15,000,000 degrees Celsius.- The earth and all bodies of the solar system is attracted to the sun by its

gravitational attraction.- The earth revolves around the sun in one year.- The earth is tilted on it’s axis 23 ½ degrees which gives us the length of day and

seasonal changes throughout the year.- Because of the Earth’s tilt, there are only two times during the year when the

sun shines equally on both the Northern and Southern Hemispheres.

- Equinoxes: Derived from a Latin word meaning “Equal Night”. March 20 to the 23th rd

September 20 to the 23th rd

- Solstices: Derived from a Latin word meaning “Sun Stands Still”.Furthest the sun reaches North and South of the Equator.Northern Hemisphere - Tropic of Cancer - 23 ½ degrees NSouthern Hemisphere - Tropic of Capricorn - 23 ½ degrees SLongest day in the Northern Hemisphere June 21 (approx.)

??? Longest day in the Southern Hemisphere December 22 (approx)



Old Text Relationship Between the Earth and the Sun

1. Seasons- simply the extended periods of greater or lesser heat- Seasons are determined by:

Î The earth’s shapeÏ Tilt of the axis of the earthÐ Movement of the earth in space

2. RotationThe earth rotates on its axis every 24 hours causing night and day. This ensures that no area of the earth receives only the warming effect

of the sun, while other areas receives no warming effect at all. The result is the evening out of the temperature on the earth.

3. RevolutionIts a term given to the nearly circular path or orbit. The earth moves around the sun. When the Northern Hemisphere is tilted towards the sun it receives

an increase in the number of hours of sun as compared to the Southern Hemisphere. Thus we receive a warming effect.

@ The second thing to note is that when the earth is tilted on its axis it allows the Northern Hemisphere to receive more direct sunlight,

decreasing the amount of area for the sun to cover.*** Same is true when the Southern Hemispheres is tilted toward the sun.

See Page 56 / Figure 4.3

http://www.onr.navy.mil/focus/spacesciences/observingsky/

http://www.onr.navy.mil/focus/spacesciences/observingsky/motion





Old Text Equinoxes and Solstices:1. Equinoxes

The time of the year when days and nights are equal on the earth. At this point the sun’s rays are directly overhead at noon.

Time: March 21 and Sept. 22 or 23......*** Use your text for these dates between the 20 and 23 th rd of the month.

Equinoxes Northern Hemisphere Southern Hemisphere

March 21 known as vernal or springequinoxes (beginning ofspring)

autumnal equinox (Beginning of fall)

Sept. 22/23 autumnal equinox(beginning of fall)

vernal or spring equinoxes(beginning of spring)

Note: [equinox]The equinox in 1990 was March 21 at 21:10. [9:10 PM] In 1995 it was at 2:15 and in the year 2000 it was at 7:31. In September of 1990, the equinox was on the 23 at 7:01. rd

In 1995 it was on the 23 at 12:06 and in the year 2000 it was rd

on the 22 at 17:18. [5:18 PM]nd

2. SolsticesThe time when the sun seems to reverse its apparent movement North or South of the equator. It is the farthest North or South of the equator the sun’s rays would reach when its at right angles of the earth.Approximately 23.5 degrees North or South of the equator.

Tropic of Cancer is in the Northern Hemisphere and Tropic of Capricorn is in the Southern Hemisphere.

Solstices Northern Hemisphere Southern Hemisphere

June 21 summer solstices (thelongest summer’s day)

winter solstices (the shortestwinter’s day)

December 22 winter solstice (the shortestwinter’s day)

summer solstices (thelongest summer’s day)

Questions.....Page 55, 56.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 6, 7, 8, 9, 10



http://liftoff.msfc.nasa.gov/News/2000/News-Summer.asp [ audio]

Worksheets 3200. . . #’s 1,2,3

A-1. Sunlight and Clouds( see fig. 4.4/p 57). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pg 56

- Distribution of sun’s energy:- 49% absorbed by the earth’s surface- 17% 2 2 absorbed by C0 , H 0, & Dust- 6% scattered by atmosphere- 4% reflected by earth’s surface- 24% reflected by clouds

??? âNote: Water absorbs energy but also reflects energy.Snow and ice mainly reflect solar energy.Vegetation’s absorption and reflection rate is somewhere between that

of water and snow.

- Clouds may reduce the amount of energy the earth receives but it also reduces the amount radiated back into space from the earth.

- Clear Days...............the amount energy radiated from the sun to the earth (daytime) and from the earth to the sun (night time) is at it’s maximum. Temperature ranges between day and night are the greatest.

- Cloud Days................the amount of energy absorbed from the sun is limited, the amount radiated back into space is also limited by the clouds. Temperature ranges between day and night are not great.

??? ãNote: Greenhouse Effect:

The ability of the air to hold heat waves from the earth after letting the sun’s rays pass through it.

Greenhouse Effect: As the heat energy is reflected back and forth between earth and theatmosphere, it performs a very useful function. It modified potentially extreme ranges of temperature.

Questions.....Page 57.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 11, 12

http://liftoff.msfc.nasa.gov/News/2000/News-Summer.asp



B. Patterns in Temperature: (see fig. 4.3 pg 56). . . . . . . . . . . . . . . . . . . . . . . . . . . . . pg 57- Two things which affect weather- âWe have just learned that one thing that affect Earth’s range in daytime and

nighttime temperatures was the amount of cloud cover.- ãThe second thing that affect temperature is the curvature of the earth.- The Earth’s equator received more radiation (radiant energy) than the polar region- The equator... (and equatorial areas of the Earth)... receives the direct rays

of the sun and has less surface area to warm. [Fig 4.3... “E”]- The polar regions of the earth receives the sun’s rays at an angle (obliquely)

this means that the sun’s rays have more surface area to warm.[Fig 4.3... “F”]- The more surface area to warm the less affect the sun’s energy will have.- What will happen to the temperature as we move away from the equator

and toward the poles?- See page 58, fig 4.5 to confirm your answer.

K low latitude high temperature (Panama 8 N.....28 Celsius)0 0

K high latitude low temperature ( Alert, Canada 82 North.....-14 Celsius)0 0

- - The further north and south of the equator the lower the temperature

Questions.....Page 58, 59.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 13, 14

Worksheets 3200. . . #’s 4,5,6

C. Wind: The Movement of Air.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pg 59

- As we have seen the sun’s rays hits the Earth’s surface unevenly- The Earth’s warm surface warms the air above it.- Questions:

1. What happens to this warm air? “Convection, Convection,.....”2. Does the warm air move?3. Does it stay in the same place?4. If it does move do it move in patterns?

- Generally the following happens:K Warm air over the equator is heatedK Warm air expands, becomes less dense and more buoyant K Warm air risesK Cool air above this warm rising air is forced toward the polar regions

(North and South)K As the cool air becomes more dense and begins to sink back to earth in the



polar regions it begins to warm and displaces the cooler air just abovethe surface of the higher latitudes.

K This cool air is forced to flow toward the equator.K This flow of air from the equator to the poles and back again to the equator

along a lower path is called a “Convection Cell”.K The result is a more even distribution of heat around the earth.K Without convection cells the world wide temperatures would have a

wider range.

K The key factor driving convection is density. (Warm air is less dense than cool air)

- A similar situation occurs with humidity.(Humid air is less dense than dry air).

- A warm moist air creates low pressure areas- A cool dry air creates areas of high pressure- Differing air masses close to each other causes a flow of air from a

“high pressure to a low pressure”High pressure / more dense to - - - - a low pressure / less dense

- This air flow is “wind”... air flows horizontally in “wind systems”

http://www.school-portal.co.uk/GroupHomepage.asp?GroupId=21401

Directions: Geography / Physical Geography animation / bottom pg ...if you like these animpage opens to “Exploring earth” go to chapter 19 / “land and sea breezes”

Questions.....Page 61, 62.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 15, 16

C-1 Prevailing Winds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pg - Winds rising from the equator and moving toward the poles and back

again are complicated by two factors.Î The Earth’s Rotation (Coriolis Force) and Ï The uneven distribution of land and water over the Earth’s Surface.

- This results in “three” convection cells for each hemisphere (Northern & Southern Hemisphere)

- REMEMBER: Winds move from a high pressure area to a low pressure area

http://www.classzone.com/books/earth_science/terc/navigation/




- These six convection cells are called the “Prevailing Winds”

- Prevailing Winds:(See pg 63 left side)Î Northeast Trade Winds........0 degrees to 23.5 degrees NÏ Southeast Trade Winds........0 degrees to 23.5 degrees SÐ Westerly Winds...................23.5 degrees to 66.5 degrees NÑ Westerly Winds...................23.5 degrees to 66.5 degrees SÒ North Polar Easterlies.........66.5 degrees to 90 degrees NÓ South Polar Easterlies.........66.5 degrees to 90 degrees S

Note: Many readings will show them at ..... 0 to 30 ..... 30 to 60 ..... 60 to 90 degrees.

Worksheets 3200. . . #’s 7,8,9

Old Text... [CORIOLIS FORCE]X the tendency for the prevailing winds to blow in an oblique rather

than a straight path.X objects of fluids moving horizontally will be deflected to the

right of their movement in the Northern Hemisphere and to the left in the Southern Hemisphere

[ must stand at a high pressure zone to see this ].

X at the equator the movement is slight but increases as you move towards the poles.

X both the coriolis force and air movement produces the following wind systems:1. Northeast Trade Winds2. Southeast Trade Winds3. Westerlies4. Polar Easterlies

X because of the trade winds and the westerlies, the warm air of the equator andthe cold air of the poles are constantly mixed and thus moderate thetemperatures.

X Note: Canada receives cold air from the North and warm air from the South -Australia on the other hand receives warm air from the North and coldair from the South.






Directions: Geography / Physical Geography animation / bottom pg ...if you like these animpage opens to “Exploring earth” go to chapter 19 / “Coriolis force”

Questions.....Page 63.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 17, 18, 19, 20

- Two factors affect air movement in Fig. 4.11Î Variations in Earth’s Surface..........remains constant throughout the year.Ï Earth’s position relative to the sun..........varies depending on the season.

- As the Earth revolves around the sun the position of direct sun rays changes from the Tropic of Cancer to the Tropic of Capricorn.

- As a result of this change the wind systems change.- Fig. 4.11 is a theoretical movement.- Fig. 4.12 are actual changes for January and July.

*** - - - High pressure area is further north in July See Fig 4.12 Pg. 65

Questions.....Page 64.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 21

StopC-2 Winds and Precipitation Patterns:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pg

- Air can vary in many ways..........temperature, density, and pressure. - Air may also vary in Humidity.- Humidity is the amount of moisture content in the air.- Moisture is gained from water bodies on the earth which is evaporated.- Keep two things in mind when analyzing the precipitation diagram on page 66, 67

Î When warm air cools, it cannot hold as much water vapor.Ï Temperature rises as air pressure increases. Temperature lowers as air pressure decreases.

Types of Precipitation

Relief or Orographic Convectional Frontal or Cyclonic






Directions: Geography / Physical Geography animation / bottom pg ...if you like these animpage opens to “Exploring earth” go to chapter 20 / “Compare and contrastwarm and cold fronts”

Questions.....Page 64, 65, 66, 67, 68.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 22, 23, 24, 25, 26

D. Other Factors Affecting Climate:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .- What general patterns of weather and climate have we seen so far

(a) Features of air that affect weatherÎ temperatureÏ humidityÐ pressureÑ movement in convection and windÒ formation into clouds

(b) Earth’s.....influence on the weatherÎ revolution around the sunÏ shape.....[direct rays at the equator.....oblique at the poles]

(c) What then can we say about weather ????Î Temperature tend to decrease as latitude or distance

from the equator increases.- The scattergraph on page 59 supports this statement

- We do see however some unusual situations: ????????Î England’s Southern tip, although 50 degrees N can support palm trees.Ï La Paz, in Bolivia,[tropical area] approx.15 degrees South,

the average temperature rarely exceeds 10 degrees Celsius.

- What accounts for these unusual situations?- The next three sections considers the causes of such unusual situations

D-1 Ocean Currents and climateD-2 Continentality and ClimateD-3 Elevation and Climate

D-1 Ocean Currents and Climate ( fig. 4.7/page 60)- Oceans cover over 70% of the Earth’s surface- Oceans like air have their own pattern of flow- All oceans contain a series of Ocean Currents



- Wind drag over the surface of the water is the primary cause of ocean currents.- Three factors have an influence on how ocean currents flow

(1) - “Coriolis Force” (rotation of the Earth’s.........Ocean Currents move right or left depending on the Hemisphere.

(2) - Ocean Currents are affected by the “Size and Shape” of the body of water in which they develop.

- Eg., The Gulf Stream is deflected to the North and to the East by the shape of North America.

- Other currents throughout the world are affected in a similar way.........Japan Current, Brazil Current, etc.

(3) - Ocean Currents are influenced by differences in “Water Temperature and Salt Content”.

- These differences cause convection currents to develop much the same way as wind systems develop with differences in air temperature.

- Fig. 4.7/p. 60 .........shows that ocean currents have a clear affect ontemperatures throughout the world.

Questions.....Page 68, 69. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 27, 28, 29, 30

D-2 Continentality and Climate: (Land and Sea Breezes)- How does continentality affect climate

â Land warms up faster.... but cools down fasterWater warms up slow .....but cools down slowClimates on land, near water, will be affected

ã Wind patterns will affect climate- Why is sea air cooler than land air in the daytime but warmer at night?- Part of the reason lies with the fact that water masses heat up and cool

down more slowly.- The reason for water masses warming up slowly is due to its translucent nature.- Sunlight is absorbed to great depths, thus it requires large amounts of

solar energy to heat the water.

- Questions- Will coastal lands be affected if water loses it’s heat energy slowly?



- How might a large body of water influence a land areas temperature range.- Temperature Range: the range between the highest and lowest average

annual temperature?

Questions.....Page 69. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 31, 32, 33

- Another way continentality affects climate involves wind patterns.- 4.11 shows the prevailing winds during an equinox

(sun is shining directly over the equator).- Top of fig. 4.12 shows the prevailing winds in January (NH) the Earth

is tilted away from the sun.- Sun’s power is now more powerful south of the equator and the Earth’s

Convection cells has moved south.- Therefore, each wind system should shift southward.- Although, the convection cells has moved we find many more changes

and modifications than expected.- During the July move when the convection cells travel North we still see

many changes and modifications.- What is causing these changes????? ú - Remember the oceans take longer to warm up and cool down.

- Winds then will blow differently in coastal areas than in continental areas.[inland areas]

- Topography (hills, plains, etc) will have an effect on wind.- Winds are sensitive to the Earth’s Surface variation

(mountains, plains /arid areas, wet areas).

- A change in wind and pressure can profoundly affect climate. (Profound effects extreme variation)

Public Exam: ..... India:(see fig. 4:12........monsoon winds)- This effect can be seen in India (Northern Hemisphere).

Winter - During the winter the Central Asian Continent has cold temperatures and a large area of “High Pressure” develops.

- Strong winds blow Southward off the land creating very dry conditions (see January, fig. 4.12). (Winds evaporate moisture from the land, even though it is a cool wind) (Remember you are in India) (Mean Annual temperature New Delhi 25 degrees Celsius.

Summer - During summer the situation reverses in summer when a large



“low pressure” system forms over the hot Asian interior.- Winds blow northward off the Indian Ocean.- These winds hold a great deal of precipitation which is accumulated

from the Indian Ocean.- When these winds meet the mountains and highlands of India heavy

rains occur.Monsoons - This seasonal change in wind direction is called the “Monsoon”

Questions.....Page 71.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . # 34, 35

D-3 Elevation and ClimateFactors affecting climate

Ocean current,.... Continentality, ....Prevailing winds, ....and Elevation- Elevation (altitude)..........how high a region is above sea level- Elevation influences

Î TemperatureÏ Rainfall Distribution

- Temperature: for every 300 meter rise temperature drops approximately 2 degrees Celsius.

- Remember: Canadian Geography..........when condensation is not occurring, temp drops 1 degree”.

for every 100 meters rise in elevation...........when condensation occurs temperature drops 0.6 degrees

for every 100 meters rise in elevation.- Rainfall:.... As air rises and temperature drops..... moisture in the air

condenses and fall as rain.

- Remember:.... Term..........Windward..........The side that faces the coast and against which the wind blows..........The side on which the rain falls.

- Remember: Term..........Leeward..........The side opposite the Windward Side..........Side facing an interior land region..........this side of the mountain experiences a “rain shadow” effect.

- Remember: Term.........Rain shadow..........Dry conditions created on theleeward side of mountains when moist winds cause precipitation on the windward sides.

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Unit Two / Chapter 4 Weather and Climate - Wikispaces04+Notes.pdfUnit Two / Chapter 4 Weather and Climate Page 1 of 13 A scension Collegiate