Climate Basics

Energy from the sun through insolation. 50% absorbed by earths surface and released as infa-red radition heating the troposphere - the other 50% is split threeways: 

• 25% reflected back into space by clouds and air 
• 20% absorbed by air and clouds
• 5% reflected back into space by the earths surface 

4 main factors effecting solar radiation: 

• Solar constant -varies when the sun is more or less active 
• Earths distance from the sun - changes due to the orbit 
• Latitude of the sun in the sky - equator = higher so spreads over smalle surface area, poles =lower so less solar radiation per mtere squared
• Lenght of day and night - varies with the seasons

High latitudes = cold due to sun lower in sky and fewer hours of daylight

High altitudes = cold due to air pressure means fewer air molecules and conduction means the further form the source of heat the cooler it is.  

Winds:

• large scale movements of air due to air pressure chages, caused by atmospheric heating differences from the poles to the equator 
• part of global atmospheric circulation cells which have warm air = low pressure and cool air = high pressure 
• winds move from high pressure to low pressure 
• three types of cell are the hadley, ferrel and polar 

How it works: 

• equotor= warm so air rises creating low pressure clouds and rain = ITCZ 
• air rises and cools moving 90 degress north and south 
• cool air sinks = high pressure and sub tropical jet streams 
• cool air reaches the ground which moves it back towards the equator or towards the poles, creates surface winds - trade winds, where they converge it is the ITCZ = they rise and form clouds 
• 60 degrreees from equator warm surface winds meet cold winds and warm air rises = low pressure
• poles = cool air sinks = high pressure  

• They are large scale movements of water due to water density, which depends on water temp and salinity 
• Currents = affected by surface winds, position of land masses and other currents
• transfer heat from warm to cool regions
• Ocean currents form loops that travel clockwise in the N hemisphere and anti in the S hemishpere because trade winds push water W aklong the equator and westerlies push water E along the ferrel cell