EE18

Question 1

What are climates affected by?

Answer 1

Latitude
Altitude
Aspect
Martime
*climates determine hear moisture and sunlight available*

Question 2

What happens to intensity of light with increasing latitude?

Answer 2

Intensity is radiation per unit area
Area over which radiation is received increases with latitude, thus intensity decreases with increasing latitude.
INTENSITY IS INVERSLEY PROPORTIONAL TO THE COSINE OF LATITUDE.

Question 3

What is a weather front?

Answer 3

boundary seperating 2 masses of air of different densities.

Question 4

Why is it colder closer to the poles?

Answer 4

The suns rays hit the earth perpendicularly at the equator.
North/south of this the suns rays are steeper.
The amount of atmosphere rays must pass through increases towards the poles.
Therefore more radiation is reflected and absorbed per unit area before it reaches the surface.

Question 5

Why do clouds form?

Answer 5

Solar radiation heats up the earths surface.
The surface warms and emits IR to the atmosphere.
Differences in heating of different parts create pockets of warm air surrounded by cooler air.
Warm air is less dense and so rises =uplift
As the warm air rises is expands as there is less atmospheric pressure.
This expansion cools the rising air.
The cooler air cannot hold as much water vapour.
Water condenses to droplets- clouds.

Question 6

What is subsidence?

Answer 6

The tropics receive the most precipitation of any area as they get the most solar radiation therefore the most surface heating. Therefore the most uplift of air and cloud formation.
This uplift creates a band of low atmospheric pressure relative to north and south.
When air rising reaches boundary between troposphere and stratosphere it flows towards poles.
Poleward moving air exchanges heat with the surrounding air and cools.
Once at a temperature similar to surrounding atmosphere it descends. This descending is subsidence and is the opposite of uplift.

Question 7

What affect does subsidence have?

Answer 7

Subsidence creates regions of high pressure at lattitudes 30 degrees North and South, which inhibits precipitation -cloud formation. = horse lattitudes.
This is where most deserts are found.

Question 8

What is the Hadley Cell?

Answer 8

Tropical uplift of air creates large scale atmospheric circulation in each hemisphere

Question 9

What is the Ferrell cell?

Answer 9

Exists between the Hadley and Polar cells and driven by movement of Hadley and polar cell and exchange of energy between tropical and polar air masses.

Question 10

What is the Polar Cell?

Answer 10

Cold dense air subsides at poles and moves towards equator when it reaches earths surface.
The descending air is replaced by air moving through the upper atmosphere from lower altitudes.

Question 11

What does subsidence at poles cause and what is the consequence of this?

Answer 11

Subsidence at poles causes high pressure, therefore there is little precipitation in polar regions, despite ice and snow.

Question 12

What do the 3 atmosphere circulations establish?

Answer 12

The three climatic zones
30 degrees N/S = tropical
30/60 degrees N/S = temperate
60* N/s = polar

Question 13

What causes prevailing winds?

Answer 13

wind flows from areas of high pressure to areas of low pressure.
areas of high and low pressure are formed by atmospheric circulation cells which give rise to consistent movement at earths surface.
=prevailing winds.

Question 14

What is the Coriolis force?

Answer 14

The earth is moving around its axis from west to east.
The speed of the atmosphere is faster at the equator.
Northward flowing air moving away from the equator is deflected to the East.
Southward flowing air moving away from the equator is deflected to the west

Question 15

What phase is the earth currently in and what is this characterised by?

Answer 15

A cool climatic phase.

characterized by regular periods of cooling glacial formation and advance and the reverse.

Question 16

What are milankovitch cycles?

Answer 16

The suggested caused for the interglacial cycles that occur at frequencies of about 100,000 years.
= combination of regular changes in the shape of the earths orbit and tilt of the axis - changes the intensity of solar radiation at high altitudes.

Question 17

How does the earths orbit change, and what effect does this have?

Answer 17

Earths orbit shifts between circular and elliptical shape in regular cycles (100,000 years)
In elliptical there is a greater distance from the sun at aphelion which means less solar radiation = climate change.

Question 18

Why are there colder climates at higher elevations?

Answer 18

atmospheric pressure and therefore air density decrease with increasing elevation.
Fewer air molecules to absorb IR
The air expands as it rises which leads to more heat loss and temperature falls at 10 degrees per km. = dry adibatic lapse rate.
water condenses as air cools and gains heat of condensation =moist adiabatic lapse rate = 6 degrees per km.

Question 19

What is the lapse rate?

Answer 19

Decreasing temperature with increasing altitude.

Question 20

How often does the angle of the earths tilt change and what effect does this have?

Answer 20

changes in regular cycles of about 41000 years.

-greater the angle of tilt, greater the seasonal variation.

Question 21

When do sun spots occur?

Answer 21

Sun spots occur in 11 year cycles and are connected with other solar events like solar flares and solar weather

Question 22

What classifies biomes?

Answer 22

Whittakers climatic community.

average annual temperate/average annual precipitation =

Question 23

What is albedo?

Answer 23

solar energy reflected back into space

eg. snow increases albedo.

Question 24

What happens to the effect of aspect with altitude?

Answer 24

effect of aspect increases with altitude.

eg. opposite sides of a hoof print have different microclimate.

Question 25

What is the rain shadow effect?

Answer 25

In the andes and sieria nevada= lose moisture as precipitation before cresting summit= less moisture and warm air as move down eastern slope.
The windward side therefore has more moisture = more lush and productive.
The Leeward side has more drought resistent vegetation.

Question 26

Why does cool polar water move to tropical regions?

Answer 26

Deep and surface water dont mix due to differences in temperature and salinity.
-warm tropical water reaches polar regions and loses heat, becoming cooler and denser.
Cools enough for ice to form which increases the salinity of the remaining water.
The cooler and saltier water is denser and sinks deeper.
Downwelling currents therefore move to the equator carrying old polar water to warmer tropical.

Question 27

What is an el Nino year?

Answer 27

when normally productive oceans have fewer fish
caused by weakening of easterly trade winds by oscillations in positions of high pressure and low pressure cells over equatorial pacific.
lasts 18 months
intervals of 3-8 years
fire more likely in el nino as precipitation decreases in aus and sea.
increased precipitation in the states