Y13 Climate And Weather

Question 1

Define climate

Answer 1

Expected weather based on long term collection of data

Climate = average atmospheric conditions over a long period of time

Weather = short period

Question 2

5 factors that affect climate

Answer 2

Solar energy (overhead sun at equator)

Earth tilt (seasons)

Wind formation (temp differences)

Pressure differences

Coriolis effect

Due to latitude, altitude, topography, presence of large bodies of water and presence of air currents

Question 3

Describe and explain orthographic lift

Answer 3

Air moving up and over a mountain.

Air rises, spreads, cools.
Dew point reached - condenses, forms clouds and rain on the WINDWARD side
Steeper mountain faster winds, heavier ppt

Rain shadow on LEEWARD side

Question 4

How does atmospheric pressure impact climate?

Answer 4

Air naturally wants to flow from high to low pressure

Combined with rotation of earth, areas of different pressure create wind

High pressure - descending air suppresses weather development, sunny and clear (or trapped fog)

Low pressure - winds rapidly circulate inwards and upwards, rises and cools, ppt

Question 5

What do isobars show on a weather map?

Answer 5

Iso = same

Areas of the same pressure

Winds tend to blow along isobars
Isobars close together = strong winds

Question 6

How is wind flow affected by topography?

Answer 6

Affected by contours:

Valleys - wind speeds up when forced through a gap

Up mountains - wind speed up as more air must pass between mountain and tropopause

Down - wind speed high as air warms and is compressed

Question 7

What are cyclones and anticyclones?

Answer 7

Cyclone - isobars enclose area of LOW pressure (converging air), forms storms
Coriolis - acw in NH, cw in SH

Anticyclones - isobars enclose area of HIGH pressure (diverging air), cool air descends, fine weather

Question 8

Pressure systems and coriolis in the Northern and Southern Hemispheres

Answer 8

NH
Highs (air down) CLOCKWISE
Lows (air up) ANTICLOCKWISE

SH
Highs ANTICLOCKWISE
Lows CLOCKWISE

Question 9

What are weather fronts

Answer 9

Boundary between two air masses which have different temperature and humidity

Reaction often brings dramatic change in temp and weather conditions
Larger difference = more intense

Question 10

Types of weather front s

Answer 10

Warm fronts (semicircles, red)
Semis indicate direction of warm air
Warm air replaces cold air, less dense so rises up, forms clouds… ppt

Cold fronts (triangles, blue)
Cold air replaces warm, denser so pushes under, warm air forced to rise, ppt
Distinct change in weather

Occluded fronts
Cold front ‘catches up’ with warm front, lifts warm air, hiding it from the surface

Question 11

Precipitation, how different types are produced

Answer 11

Any product of the condensation of atmospheric water vapour that falls due to gravity

Depends on temp.
Rain, freezing rain, sleet, snow

Question 12

Describe NZ’s general rainfall pattern

Answer 12

Prevailing westerlies

Therefore high rainfall on windward side of southern alps (West)
Winds laden with moisture from the Tasman forces to rise quickly

Rain shadow - East side of SI very dry (Canterbury plains)

Question 13

Describe NZ general temperature

Answer 13

Sunlight angle - NI receives more direct sunlight

Altitude - high alt southern alps lower temp than sea level

Question 14

Describe NZ winds and what they bring

Answer 14

Westerlies - “roaring forties” bring low pressure systems to NZ
Wet weather upwind mountains

Northerlies - bring tropical storms —> floods

Southerlies - bring cold air from Antarctica —> snow at low altitudes

Question 15

Describe katabatjc and anabatic winds

Answer 15

Mountain/valley breezes occur as higher surfaces are heater or cooled faster

Katabatic = wind comes down from mountains into valleys
(Night)?

Anabatic = rise from valleys to mountains
(Day)

Question 16

Describe the earth-atmosphere energy balance

Answer 16

Balance between incoming solar radiation (insulation) and outgoing energy from earth

Sun - shortwave, UV, some reflected, some absorbed

Earth cooler than sun - infrared
Radiate energy into atm as heat

Question 17

Greenhouse gases
Common ones

Answer 17

Water vapour (95%)

Carbon dioxide (atm levels increased by 1/3 since start of industrial rev)

Methane

Nitrous oxide

CFCs - chlorofluorocarbons (destroy the ozone)

Question 18

Define atmospheric feedback

Answer 18

Feedbacks = interactions between climate variables that can control or limit the greenhouse effect

Occur when outputs of a system are routed back into the system as inputs

Question 19

Positive and negative atmospheric feedback

Answer 19

Positive = INCREASE avg atm temp
Speeds up warming
Decrease albedo

Negative = DECREASE avg atm temp
Slows down warming
Increase albedo

Question 20

Define albedo

Answer 20

The ability of a surface to reflect radiation
(Clouds, ice, water)

Question 21

Examples of positive feedbacks

Answer 21

Water vapour - temp rise, atm can hold more water vapour, increased GHE, increases temp more (runaway GHE)

Cloud - feedback of terrestrial radiation
More vapour = more clouds = more infrared reflected

Permafrost melting - arctic permafrost melts, releases trapped methane

Warming oceans - absorb less CO2, more in atm

Question 22

Examples of negative feedback

Answer 22

Clouds reflect sunlight - increased cloud cover causes more to be reflected back into space

Desertification
Temp rise, more deserts form, which have high albedo, more sun’s radiation reflected