Earth's climate system and redistribution of heat Flashcards
What five components does the Earth’s climate system consist of?
the atmosphere, the hydrosphere, the cryosphere, the land surface, and the biosphere
What is the Earth’s climate system influenced by?
It is an interactive system forced or influenced by various external forcing mechanisms, the most important of which is the sun
How is the Earth’s climate influenced by the sun?
Incoming solar radiation
How does the Earth’s shape influence the amount of incoming solar radiation?
Low angle of incoming sunlight rays spread over wide area
Sunlight directly overhead, rays spread over a narrow area
Low angle of incoming sunlight, rays spread over wide area
What are the three major greenhouse gases?
H2- water vapour
Co2- carbon dioxide
CH4- methane
Anything with what temperature emits heat?
-273 degrees celcius/0 kelvin
What amount of heat is returned to space?
Amount of heat returned to space is less than Earth’s average temperature; would be for an average planetary temperature of -16 degrees, where as our planets average temoerature is +15 degrees
What percentage of longwave back radiation emitted from the surface is absorbed by greenhouse gases?
95%
What is albedo?
the percentage of incoming radiation that is reflected rather than absorbed by a particular surface
What sort of surfaces act in albedo?
Fresh snow or ice
Old melting snow
Clouds
Desert sand
Soil
Tundra
Grasslands
Forest
Water
What influences the albedo of a surface?
Varies with angle of incoming solar radiation
Low latitude- less reflected more absorbed
High latitude- more reflected less absorbed
What is an example of a positive cooling feedback?
Initial change
Climate cooling
Increased snow and ice: high reflectively
Less solar radiation absorbed at surface
Greater cooling
How does incoming radiation and albedo vary seasonally?
The tilt of the Earth’s axis in its annual orbit around the sun causes seasonal shifts between the hemispheres in the amount of solar radiation receives at the Earth’s surface
What is key to Earth’s climate system?
Water key to Earth’s climate system
Heat capacity: measure of the ability to absorb heat
Water- 60
Ice- 5
Air- 2
Land- 1
What causes air at the surface to begin rising?
warming of the surface heats the air, causing it to expand, become less dense, and rise
What happens to the air as it rises higher into the atmosphere?
It encounters lower air pressure, expands further, and cools
Why does rising air cool as it expands?
Expansion uses energy, which reduces the temperature of the air parcel
What is the effect of cooling on rising air?
Cooling makes the air denser, which can slow or stop its ascent unless other factors support continued rising
How does water vapor help air rise?
Water vapor from evaporation lowers the airs density, helping it rise
What happens when rising air cools to dew point?
Condensation begins forming clouds
What is latent heat and why is it important in the atmosphere?
Latent heat is released during condensation, warming the air and making it less dense so it can rise further
What process helps overcome stable atmospheric layering?
Heating, evaporation, and condensation combine to reduce air density and drive upward motion, disrupting stability
What is an example of an important positive climate feedback?
Initial change
Climate warming
Increased atmospheric water vapor
Increased greenhouse trapping of radiation
Increased warming
What do the tropical and subtropical regions have?
They have net excess of incoming solar radiation over outgoing back radiation
Excess tropical heat is store din a thin layer of the tropical ocean
Heating imbalance drives Earth’s general atmospheric and ocean circulation
What is a summer monsoon?
Rapid heating of land surface produces rising air motion over continent
This draws in moist air from the oceans, causing heavy precipitation
What is a winter monsoon?
Rapid cooling of land surface produces sinking air motion over continent
This sends cold dry air out over the warmer ocean, shifting the foci of precipitation
What are the surface ocean currents driven by?
Winds
What is the coriolis deflection?
It is the apparent deflection of moving air (or any object) due to Earth’s rotation- to the right in the Northern hemisphere and to the left in the Southern hemisphere
What is thermohaline circulation?
A global ocean circulation driven by differences in water temperatures (thermo) and salinity (haline) which affect water density. Cold, salty water sinks and drives deep ocean currents
How does deep water come to the surface?
Upward diffusion of water too slow
Coastal upwelling
