Atmospheric heat budget
- Created by: khiggs1
- Created on: 12-10-16 19:07
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- Atmospheric heat budget
- Heat transfer
- Horizontal heat transfer
- 80% of heat transferred away from tropics & carried by winds e.g.j et streams or depressions or hurricanes
- 20% moved by ocean currents polewards
- Vertical heat tranfer
- From warmer surface of the Earth vertically
- Conduction , radiation, convection and a little bit of latent heat
- e.g. latent heat is needed to change water(ocean) into vapour which may rise until it condenses much higher (cloud)
- Causes precipitation which will release energy and warm up the atmosphere
- From warmer surface of the Earth vertically
- Horizontal heat transfer
- Factors affecting insolation
- Short term effects
- Seasonal Change
- Insolation is equally distributed in each hemisphere in autumn and spring equinoxes - overhead the equator
- In summer and winter solstices the sun is overhead the tropics maximum insolation are in the noth and south hemisphere
- Diurnal change
- The length of day and night varies in locations away from the equator
- Polar regions - no insolation during winter when the region is tilted away from the sun
- Local
- Aspect
- Slopes alter the angle at which the sun strikes Earth - South facing slopes
- Urbanisation
- Urban surfaces tend to absorb more heat
- Cloud Cover
- Can reflect absorb insolation but can also act as an insulating blanket which can cause either a rapid fall or increase in temperature depending on the conditions
- Aspect
- Seasonal Change
- Long term effects
- Prevailing wind
- The air mass is determined by the area that it has passed
- Wind blowing over the sea tend t be cooler in summer and warmerr in winter
- Mainly westerly
- Proportion of land and sea
- Land heats up quicker
- Sea is low of density and increased specific heat capacity
- Land heats up quicker
- Ocean currents
- Caused by influence of prevailing winds
- Warmer currents migrate pole wards + cold currents replace them
- Gyre - circulatory motion
- North hemisher - move clockwise opposite for south
- Cause currents to go west- north Atlantic drift + Gulf stream
- Altitude of the sun
- At higher latitudes the energy from the sun pass through more atmosphere
- Less concentrated d curvature of Earth , heating more land compared to the equator
- At higher latitudes the energy from the sun pass through more atmosphere
- Ocean conveyor belt
- Transfer of cold water from the polar regions to the equator
- The movement of less salty and less dense effect the temperature of the North Atlantic
- Altitude of land
- Insolation heats surface, warms the air above
- Higher land is further away from heat source
- The main mass of land is heated by insolation meaning higher land is cooler
- The density decreases with height adding to cooling effect
- Prevailing wind
- Short term effects
- Solar Energy Budget
- Insolation - 100%
- Long wave - 66%
- Absorbed
- 14% atmosphere
- 51% Earth
- Reflected
- 27% Clouds
- 2% Earth
- 6% Atmosphere
- Albedo - 35%
- Radiated
- 58% Atmosphere
- 8% Earth
- Evaporation
- 26% Earth
- Convection & Conduction
- 8%
- Insolation - 100%
- Global Heat Budget
- The Earth isn't heating up or cooling down, there is a balance of short wave and long wave radiation
- Look at a diagram
- Although energy is lost through radiation , the net gain radiation not experienced in the poles
- In polar regions there is a net deficit(loss)(negative heat balance)
- In lower latitudes there is a net gain
- In polar regions there is a net deficit(loss)(negative heat balance)
- The imbalance of heat transfer can be explained by many heat transfer (link)
- The Earth isn't heating up or cooling down, there is a balance of short wave and long wave radiation
- Amount of energy received from the sun
- Solar constant- rate of which energy reaches the Earth's surface from the sun
- Distance from the sun- the orbit of the Earth can cause up to 6% variation in solar constant
- Altitude of the sun in the sky - The equator is more heated as the Sun strikes the Earth head on but in the poles it is at a more oblique angle(curvature of Earth)
- Length of day & night- Curvature of Earth/tilt means that the poles receive no insolation at certain times of years
- Albedo - ratio between amount of incoming and reflected radiation
- Insolation - short wave and when reflected of Earth - long wave radiation
- Heat transfer
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