Earth's natural systems 3.3 Atmospheric processes Flashcards
Global heat budget, Albedo, lapse rate, layers of atmosphere, climate patterns (40 cards)
What is Earth’s main source of energy?
Sun- received as incoming short wave solar radiation
Define insolation
Incoming solar radiation received at particular location on Earth’s surface
What are 3 factors that determine amount of insolation?
- Distance from Sun (elliptical orbit of Earth results in variations)
- Latitude
- Length day and night (Earth axis tilts)
Albedo
ratio between incoming radiation and amount reflected into space. Expressed as percentage.
What are 2 human activities that increase albedo?
Land clearing and overgrazing
What does increase in albedo result in?
Increase albedo > increase changes of cloud formation and rain > increases risk desertification
What is albedo effect of oceans v snow and ice
oceans <10%
snow and ice 85%
What % of incoming solar radiation reaches surface directly?
24%
What is incoming radiation transformed to at Earth’s surface?
Heat energy > heats ground, radiates long-wave or infrared energy back to atmosphere
What happens to the energy that is radiated back into atmosphere?
94% is absorbed by water vapour and CO2 in atmosphere > creating natural greenhouse effect
What is the global heat budget?
Balance between incoming insolation and outgoing terrestrial radiation
What are 2 key features of the global heat budget?
- Net gain in radiation everywhere on surface except the poles (high surface albedo)
- Net loss in radiation through the atmosphere
T or F - Positive heat balance in the Tropics
Negative heat balance in poles and high attitudes
t
What does the imbalance in heat between tropics and poles result in?
heat from tropics to transfer towards poles and higher altitudes
what are the 2 types of transfer of heat?
- Horizontal- winds (80%), ocean currents (20%)… from tropics to poles
- Vertical- from surface to atmosphere by terrestrial radiation, conduction, convection currents
Define lapse rate
Air temps decline with higher altitudes in troposphere
What is lapse rate?
Air temps decrease by approx. 6 degrees per 1000m of elevation (Varies according to humidity)
T or F Air conducts heat poorly
true
At what location N/S of Equator does the body of descending air creates subtropical high-pressure belt- creating clear skies and dry stable conditions?
30 degrees N/S
Cells created by the circulation pattern of heated air from tropics rising and moving towards poles, then some descending and moving back to Equator on the surface?
Hadley cells
How do areas of low pressure called a polar cell form?
Remaining hot air moving towards poles meets cold air at polar front, warm air is lifted > polar front marks boundary warm tropical air masses and cold air polar masses (frontal zone moves as non-continuous band around Earth)
Where are jet streams in atmosphere?
Troposphere
What are surface winds caused by?
Air movements from high to low pressure areas. Variable in speed, direction but have overall global pattern
What do Hadley cells do?
- Produce descending air in mid-latitudes of both sides of Equator
- Air moves back towards Equator as surface wind
