Water cycle Energy balance Atmosphere Water cycle Energy balance

Water and polarity The hydrogen and oxygen atoms are joined by covalent bonds (a strong bond where electrons are shared). The electrons are not shared equally so hydrogen has a weak positive charge and oxygen a weak negative charge.

When two water molecules come together, the positive side of one is attracted to the negative side of the other, forming hydrogen bonds. B (oxygen atom) attracts the electron pair more than A (hydrogen atom) does.

Solid, liquid and gas

Solid The water molecules are packed close together preventing ice from changing shape. Liquid The water molecules no longer cling together as tightly and individual molecules can begin to move around each other. Gas (water vapour) The water molecules move very rapidly and are not bound together. They are still water molecules, not individual atoms. I am invisible

Maximum global evaporation rates Maximum global evaporation rates. From "Global Variations in Oceanic Evaporation (1958–2005): The Role of the Changing Wind Speed" by Lisan Yu,WHOI OAFlux project.

Electromagnetic radiation (EMR)

Electromagnetic radiation (EMR)

http://4.bp.blogspot.com/-50TB_372KIk/T1U5U1TlVXI/AAAAAAAAAQ8/xpSFhpCfr-g/s1600/solar-radiation.jpg

http://www. ecoedility http://www.ecoedility.it/e3news/wp-content/uploads/2010/05/bilacio_energetico_radiativo.jpg

A perfectly white reflecting surface has an albedo of 1 a surface looks bright When it reflects most of the light that hits it. it looks dark when most of the light is absorbed. A perfectly white reflecting surface has an albedo of 1 A perfectly black absorbing surface has an albedo of 0

Albedo Reflectivity of different surfaces on Earth http://www.earthlyissues.com/images/vitalafrica_10-threefactors_large.jpg

Global winds Wind is the movement in air caused by differences in wind pressure. The greater the difference, the faster the wind blows. Differences in air pressure are cause by uneven heating of the Earth Uneven heating produces pressure belts which occur every 30 degrees latitude Hotter air is less dense and has a lower pressure

http://science. kennesaw http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecCurrents/0804.jpg

As warm air rises (less dense) at the equator and moves towards the poles it cools As it cools some of the air sinks around 30 degrees north and south of the equator. At the poles cold air sinks and moves towards the equator Around 60 degrees north and south the air begins to heat up and rise

The combination of pressure belts and the Coriolis Effect causes global winds These are the: Polar easterlies Westerlies Trade winds

Wind belts that extend from the poles to 60 degrees latitude are formed from cold sinking air moving from the poles creating cold temperatures

Wind belts found between 30 and 60 degrees latitude flow towards the poles from west to east carrying moist air

Winds that blow from 30 degrees almost to the equator are called the Trade Winds.

The doldrums are located along the equator where no winds blow because the warm rising air creates an area of low pressure. This is also called the ITCZ or Intertropical Convergence Zone. At 30 degrees north and south are the horse latitudes. Here the winds are very weak. Most of the deserts on Earth are located here because of the dry air. Jet streams are narrow belts of high speed winds that blow in the upper troposphere are lower stratosphere. The separate warm from cold air.

http://www.srh.noaa.gov/jetstream/global/images/jetstream3.jpg