climate chpt 1

Question 1

What are the different climate types ?

Answer 1

1. tropical equatorial climates
   low annual temperature range 2-3
   high annual temperature 27
   high annual precipitation 2000m
   precipitation falls evenly throughout year
2. tropical monsoon climate
   small annual temperature range 3-5
   generally high annual temperature 25
   high annual precipitation 1500mm
   distinct wet and dry seasons
3. cool temperate climate
   large annual temperature range 21
   annual ppt 300-900mm
   ppt falls evenly throughout year

Question 2

How does air temperature vary across time ?

Answer 2

1. in a day
2. in a year

Question 3

How does air temperature vary in a day ?

Answer 3

1. earth’s rotation on its own axis
2. as earth rotates, side of earth facing sun receives solar radiation and experiences day and vice versa
3. as earth continues rotating, that side will eventually face away from sun and less solar radiation and lower temperatures
4. temperatures are different depending on time of day
   midday - hottest, sun directly overhead
   before and after midday - not as hot, sun no longer directly overhead
   before sunrise - coolest, does not receive solar radiation and heat goes back to space in the form of longwave radiation

Question 4

How does air temperature vary across year ?

Answer 4

1. earth’s revolution around sun (axis tilted at 23.5 degrees)
2. hemispheres receive different amounts of solar radiation at different times of year
   in june,
   NH leans towards sun
   in dec,
   SH leans towards sun
   in march and sep
   neither hemispheres lean to sun, both experience moderate temperatures (autumn and spring)

Question 5

What is the exception to the temperature varying across a year and why ?

Answer 5

1. the tropics
2. located near to the equator, hence receives direct / near direct solar radiation all year round
3. high temperatures all year round due to high conc of solar radiation
4. temperature variations not significant

Question 6

How does air temperature vary across places ?

Answer 6

1. latitude
2. altitude

Question 7

How does latitude affect temperature ?

Answer 7

1. at lower latitudes, conc of solar radiation is less
2. smaller solar angle, hence solar radiation is less direct (spread over large area)
3. experiences lower temperatures

Question 8

How does altitude affect temperature ?

Answer 8

1. higher altitude, less air molecules per unit volume
2. most air molecules pulled down to lower latitudes because of gravity
3. lower air pressure and air is less dense
4. less air molecules to absorb and radiate solar radiation
5. lower temperatures

Question 9

What other factors affect temperature at specific sites ?

Answer 9

1. type of surface
2. distance to sea

Question 10

How does type of surface affect temperature ?

Answer 10

1. darker surfaces eg roads in urban areas radiate more heat and absorb more solar radiation
2. skyscrapers will reflect solar radiation back to earth more (glass covered) -> more absorption of solar radiation and heat by ground
3. in rural areas, there are generally lighter covered surfaces eg clouds and snow which reflect more solar radiation back to space (longwave radiation) and radiate less heat -> lower temperatures

Question 11

How does distance from sea affect temperature ?

Answer 11

1. sea cools down and warms up slower
2. during winter, sea warmer than land, warming air along costal areas
3. during summer. sea cooler than land, cooling air along coastal areas
4. thus, experiences warmer winters and cooler summers (maritime effect) lower ATR
5. inland areas do not experience this phenomenon and do not have the moderating influence (continental effect) warmer summers cooler winters (higher ATR)

Question 12

Describe the water cycle.

Answer 12

1. water vapour enters atmosphere through evapotranspiration
   sun causes water bodies to evaporate
   plants releasing water vapour during transpiration
2. water vapour rises, cools and condenses into tiny water droplets at dew point temperature-> forms clouds
   3.water droplets become to heavy and fall to ground as rain
3. water droplets infiltrate subsurface soil and rock (groundwater flows)
4. water on ground surface flows back into body of water as surface runoff
5. groundwater flows beneath earth’s surface and horizontally above the impermeable rock

Question 13

What affects the rate of surface runoff and groundwater flows ?

Answer 13

1. type of soil
   soil with large pores, easier for groundwater to infiltrate -> allows water to move much quicker
   soil with smaller pores, harder
2. how built up the area is
   concrete surfaces, smaller pores, slows down rate of groundwater flows
   speed of surface runoff increases as surface is smoother eg roads and pavements (fewer obstructions and less friction)
3. presence of vegetation
   roots of vegetation loosen soil -> more pores for water to infiltrate and faster groundwater flows
   vegetation acts as obstacles, slowing down rate of surface runoff as there is more friction and more barriers (rough)

Question 14

How are clouds formed ?

Answer 14

1. Air rises to atmosphere
2. amt of water vapour in air exceeds max amt of water vapour that air can hold (due to low temp / increases evaporation) -> condenses
3. at dew pt temperature, water vapour condenses on condensation nuclei (ash, dust) into tiny water droplets (rain) / solid ice crystals (hail)
4. clouds and formed

Question 15

What is the process of formation of convectional rain ?

Answer 15

1. heat from sun heats up air above ground. warm air rises and cools.
2. condenses on condensation nuclei to form clouds
3. tiny water droplets collide and coalesce to form larger and heavier water droplets
4. fall to ground as rain

Question 16

What is the process of formation of relief rain ?

Answer 16

1. prevailing winds pick up moisture over the sea
2. pushes moist air up the windwards side of a mountain
3. rising cool air condenses on condensation nuclei to form tiny water droplets at dew pt temperature to from clouds
4. water droplets collide and coalesce, become large and heavy
5. rains down on windward side of mountain
6. as most moisture falls on windward side, the leeward side of the mountain experiences dry descending air and is thus dry

Question 17

How are winds formed ?

Answer 17

1. wind is the horizontal movement of air across earth’s surface
2. it is due to the diff in pressure gradients
3. hotter area, air warms up, becomes less dense and rises, less atmospheric pressure and forms a void
4. cooler area, air cools down, becomes more dense and sinks, higher atmospheric pressure
5. air moves from area with higher atmospheric pressure to area of lower atmospheric pressure to fill the void -> wind

Question 18

What determines the speed of wind ?

Answer 18

1. strength of pressure gradient
   smaller pressure gradient, less wind
2. friction
   as moving air comes in contact with variations in earth’s topography, experiences frictional drag which reduces wind speed
   eg uneven surfaces on valleys and mountains

Question 19

Why does wind direction vary on earth;s surface on a local scale ?

Answer 19

1. land breeze (both land sea lose heat in form of longwave radiation)
   at night, land cooler than sea
   warmer air above sea rises, lower atmospheric pressure, forms void
   cooler air above land sinks, higher atmospheric pressure, moves to fill void
   land breeze is formed
2. sea breeze (both sea and land absorb heat in form of shortwave radiation)
   during day, sea cooler than land
   warmer air above land rises, lower atmospheric pressure, less dense, forms void
   cooler air above sea sinks, higher atmospheric pressure, more dense, moves to fill void from lower a. pressure to higher a. pressure
   sea breeze is formed

Question 20

Why does wind direction vary on earth’s surface on a regional scale ?

Answer 20

1. unequal distribution of temperature across earth’s surface -> varied pressure zones
2. wind on earth’s surface moves from are with higher atmospheric pressure to area of lower atmospheric pressure
3. winds travel long distances, deflected by coriolis force due to earth’s rotation
   in NH, deflects to right
   in SH, deflects to left

Question 21

State process of northeast monsoon.

Answer 21

1. from oct to feb, NH experiences winter and cooler temps
   SH experiences summer and warmer temps
2. in NH, air cools and sinks -> higher pressure on central asia
3. in SH, air warms and rises -> lower pressure over Aus
4. air moves from central asia to aus
5. as air enters india, deflected to the right (coriolis effect) -> northeast monsoon experienced by countries eg india, msia and sg
6. northeast monsoon is dry and cool as little moisture picked up over central asia -> india experiences little rain
7. as wind blows over south china sea to singapore, it carries alot of moisture and brings rain to sg
8. as wind enters SH, it is deflected to the left (coriolis effect) and carries moisture over indian ocean, brings rain to indonesia and aus

Question 22

State process of southwest monsoon.

Answer 22

1. in june to sep, SH lower temp, winter
   NH higher temp, summer
2. in NH, air warms up and rises, less dense and less atmospheric pressure over central asia
   in SH, air cools and sinks, more dense and higher atmospheric pressure over aus
3. winds move from aus to central asia
4. winds cross in to NH, deflected to the right, forms southwest monsoon experienced by countries eg sg, msia and india
5. winds continue travelling and picks up moisture over indian ocean, bringing heavy rain to india