Global Climates and Biomes (Global Processes Determine Weather and Climate…
Global Climates and Biomes
Global Processes Determine Weather and Climate
the short term conditions of the atmosphere in a local area. These include temperature, humidity, clouds, precipitation, wind speed and atmospheric pressure.
The average weather that occurs in a given region over a long period- typically several decades.
Unequal Heating of Earth
Three primary causes for the uneven warming of Earth:
Angle the rays strike the Earth.
Variation in the amount of surface area over which the Sun’s ray are distributed.
Some areas reflect more solar energy (albedo).
Albedo - the % of incoming light that is reflected from the surface.
High albedo = more reflected and less absorbed.
Atmospheric Convection Currents
Air has properties that determine its movement:
Density- less dense air rises, denser air sinks.
Water vapor capacity- warm air has a higher capacity for water vapor than cold air.
Latent heat release- when water vapor in the atmosphere condenses into liquid water and energy is released.
Formation of Convection Currents
Atmospheric convection currents are global patterns of air movement that are initiated by the unequal heating of Earth.
Hadley cells- the convection currents that cycle between the equator and 30˚ north and south.
Intertropical convergence- the area of Earth that receives the most intense sunlight and where the ascending branches of the two Hadley cells converge.
Polar cells- the convection currents that are formed by air that rises at 60˚ north and south and sinks at the poles (90˚ north and south)
Earth's Rotation and the Coriolis Effect
the deflection of an object's path due to Earth's rotation.
The prevailing winds of the world are produced by a combination of atmospheric convection currents and the Coriolis effect.
Ocean currents are driven by a combination of temperature, gravity, prevailing winds, the Coriolis effect, and the locations of continents.
Warm water, like warm air, expands and rises.
Gyres- the large-scale patterns of water circulation.
Upwelling- as the surface currents separate from one another, deeper waters rise and replace the water that has moved away.
This upward movement of water brings nutrients from the ocean bottom that supports the large populations of producers, which in turn support large populations of fish.
Thermohaline circulation- another oceanic circulation that drives the mixing of surface water and deep water.
Scientists believe this process is crucial for moving heat and nutrients around the globe.
Thermohaline circulation appears to be driven by surface waters that contain unusually large amounts of salt.
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