Lec 3

Question 1

Global climate is caused by

Answer 1

The tilt of the Earth’s rotational axis and its spherical shape that make the angle of incidence of sunlight uneven at different latitudes

Question 2

What gives rise to seasons

Answer 2

The difference in average insolation at different latitudes and hemispheres

Question 3

Low temp is due to

Answer 3

Low solar radiation

Question 4

Highly seasonal environment (winter and summer)

Answer 4

Winter-No incoming solar radiation above the arctic circle

Summer-24 hour daylight and high solar input

Question 5

Which hemisphere do temps vary more

Answer 5

The Northern Hemisphere because it has less oceans to store heat

Question 6

Factors that affect global distribution of solar radiation

Answer 6

Amount absorbed by the surface, depends mainly on what grows on the surface

Amount absorbed by air

Light reflected by clouds (higher in temperate regions due to dense clouds)

Reflection by the surface is highest at the poles (more in Antarctica than the Arctic due to more snow reflecting)

Question 7

Amount of UV light reaching a surface varies with

Answer 7

Latitude

Surface orientation

Question 8

Impact of Polar ozone on UV

Answer 8

Chemical ozone destruction occurs over both polar regions in local winter-spring

Antarctic: Almost complete removal of lower-stratospheric ozone

Arctic: Ozone lose is highly variable and limited (started in 2011)

Question 9

CFC-Chloroflourcarbons

Answer 9

Breaks ozone apart, destroying ozone molocules

Question 10

Climate depends on

Answer 10

Energy received from the sun which warms land and seas

Question 11

Planetary energy balance

Answer 11

Loss of heat via long-wave radiation>energy input from solar radiation at northern latitudes

Radiation imbalances produces low temps and results in redistribution of heat from southern latitudes by air and ocean currents

Question 12

Two subtypes of climate

Answer 12

Maritime

Continental

Question 13

Maritime

Answer 13

Coastal areas with moderate stormy winters, high precipitations

Summer is cloudy and mild temp

Norway Iceland and western Alaska

Question 14

Continental

Answer 14

Much lower precipitation, great contrast between summer and winter

Question 15

General global circulation

Answer 15

Warm rising air at the equator radiates heat back into space and creates cells

Question 16

Position of continents exert secondary effect on global pattern of

Answer 16

Precipitation

Question 17

More rain in southern hemisphere because

Answer 17

More lake and oceans

Question 18

North Atlantic Oscillation (NAO)

Answer 18

The anomalous difference between the polar low and subtropical high

NAO is the dominant mode of winter climate variability

NAO is a large scale seesaw in atmospheric mass between the subtropical high and the polar low

Index varies from year to year, but also exhibits tendency to remain in one phase for intervals lasting years

Question 19

Positive NAO

Answer 19

Stronger than usual subtropical high pressure and a deeper than normal Icelandic low

Question 20

Effect of positive NAO

Answer 20

Warm and wet winters in north Europe and dry winters in north Canada and Greenland

Question 21

Negative NAO

Answer 21

A weak subtropical high and weak Icelandic low

Question 22

Arctic Oscillation (AO)

Answer 22

Arctic oscillation is linked to the NAO and driven by similar pressure differences

AO effects are not restricted just to the Arctic, it also represents an important source of variability for the Northern Hemisphere as a whole

Question 23

Are AO and NOAs correlated

Answer 23

Both have been largely positive since the end of the 1980s and have coincided with relatively warm conditions in the Arctic and net melting of the Arctic ice pack

Question 24

Polar vortex

Answer 24

An area of low pressure located in the Arctic (almost always present)

Question 25

When a polar vortex is strong

Answer 25

Cold air remains in the north

Question 26

A weaker polar vortex means

Answer 26

A wavier jet stream and cold Arctic air moves south