c2.1:L1 earth-atmosphere system and the tropics

Question 1

energy from the sun

Answer 1

insolation; shortwave radiation

Question 2

radiative transfer

Answer 2

by infrared radiation between the surface, the atmosphere, and space

Question 3

non radiative transfer

Answer 3

convection, conduction, latent heat of evaporation

Question 4

inputs into the system

Answer 4

arriving insolation: 100%
albedo reflects: 31%
absorption by atmospheric clouds and radiation: 3%
direct and diffuse radiation: 45%

Question 5

outputs from the system

Answer 5

re-rediates 69% into space; terrestrial radiation: 21%(atmosphere heating)+45%(surface heating)+3%(ozone emission)

Question 6

processes

Answer 6

absorption, reflection, scattering, conduction and convection, latent heat transfer

Question 7

what is absorption

Answer 7

assimilation of radiation by molecules of matter and its conversion from one form of energy to another
e.g. infrared radiation or chemical energy (photosynthesis)

Question 8

where does absorption take place

Answer 8

land and water surfaces, atmospheric gases, dust, cloud, and stratospheric ozone

Question 9

explain the process of absorption on the surface of the earth

Answer 9

1. when earth surface is heated up, it releases heat energy and warms the air above via radiation, conduction and convection
2. radiation emitted by warmed surface is known as terrestrial radiation; longwave radiation

Question 10

explain the process of absorption by components of the atmosphere

Answer 10

certain molecules absorb radiation.
e.g. oxygen absorbs short wave
water vapour and co2 absorbs long wave(green house effect); long wave radiation that travels back to earth known as counter radiation

Question 11

reflection

Answer 11

influenced by albedo of a surface

Question 12

albedo

Answer 12

is the reflective quality of a surface

Question 13

colour and albedo relationship

Answer 13

dark colours; low albedo
light colours; high albedo

Question 14

smoothness of surface and albedo relationship

Answer 14

smooth: increased albedo
rough: reduced albedo

Question 15

scattering process

Answer 15

1. insolation encounters increasing density of atmospheric gases as it travels to surface
2. gas molecules absorb and reemit the radiation; represents 7% of the earth’s albedo
3. dust particles, pollutants, ice , cloud droplets, water vapour produce further scattering
4. this is known as diffused radiation

Question 16

conduction process

Answer 16

1. molecule to molecule transfer of heat energy as it diffuses through a substance
2. molecule warm, vibration increase, cause collisions that produce motion in neighbouring molecules, transfers heat from warm to cool materials

Question 17

convection

Answer 17

energy transfer through gases and liquids by movements that occur when physical mixing involves strong vertical motion
e.g. warmer masses rise, cooler masses sink

Question 18

latent heat definition

Answer 18

changing of state of matter during a “constant temperature”

Question 19

evaporation vs condensation

Answer 19

evaporation: gain heat, break bonds, surrounding lose heat
condensation: lose head, form bonds, surrounding gains heat

Question 20

net radiation

Answer 20

refers to the balance of all incoming and outgoing radiation at the earth’s surface.

Question 21

net radiation across latitudes

Answer 21

equator: net gain
tropics: net gain
net gain decreases and becomes negatives towards poles

Question 22

global imbalance of radiation causes?

Answer 22

poleward transfer of heat; global atmospheric circulation pattern; wind(75%), ocean currents(25%)

Question 23

characteristics of tropics

Answer 23

1. mean temp of coolest month is 18’c
2. area between tropics of cancer and tropics of capricorn(23’N, 23’S)
3. mostly humid and arid/semiarid climates

Question 24

what causes high temp in the tropics

Answer 24

1. high solar angle/ angle of incidence
2. dist solar radiation through atmosphere
3. length of day: affected by axial tilt

Question 25

how does high solar angle affect temp

Answer 25

since insolation is dependent on the angle of the sun above the horizon, it is the greatest when the sun is overhead in the tropics. the tropics receive incoming light at a 90’ angle(subpolar point), it concentrates to a small area and increases it ability to heat the surface, hence energy is distributed to a more intense energy per unit area

Question 26

how does distance solar radiation travels through atmosphere affect temperature?

Answer 26

insolation received in tropics is concentrated over a smaller area and passes through a shallower layer of atmosphere

Question 27

how does axial tilt affect length of day which in turns affects temp

Answer 27

axial tilt produces seasonal differences in insolation at any given latitude. tropical latitudes never receive high daily maxima reached near the poles, but receive relatively large amounts of solar radiation throughout the year. there is also little variation in length of day and midday solar angle, so energy receipts exhibit little change through the year