1. Practice NAB questions The differing albedos across the earth’s surface will have an impact on the amount of solar radiation reflected by the earth’s surface. Over the tropical zones there is more vegetation, particularly at the equator where there is dense forest, this tends to absorb radiation rather than reflect. At the poles there is more radiation reflected due to the snow and ice which is white is colour. The oceans and seas also reflect a lot of radiation from the earth’s surface.

2. Practice NAB questions Include a well annotated diagram. More solar radiation is received at the tropics than the poles due to a number of reasons; the amount of surface area heated at the tropics is smaller than at the poles allowing more intense heating to take place. The amount of atmosphere which the sun’s rays have to pass through is greater at the poles than at the equator, so more radiation is reflected by clouds, dust and gases. The differing albedos can have an effect, dense forest at the equator absorbs more insolation than it reflects, whereas the ice and snow at the poles reflects more solar energy. The angle at which the sun’s rays strike the earth’s surface varies with the sun striking at a right angle at the equator and at a shallower more acute angle at the poles. Finally the equator receives two solar maxima’s a year whereas there is only one in the N+S hemispheres.

3. Practice NAB questions (c) The diagram shows the movement of winds on the earth surface. Winds are created when there are differences in air pressure. Winds blow from areas of high pressure to areas of low pressure. On the diagram it can be seen that polar easterlies blow from the high pressure zone at 90 degrees to the low pressure zone at 60 degrees. Trade winds are found blowing from the sub-tropical high pressure zone at 30 degrees towards the equator. Mid- latitude westerlies blow from 30-60 degrees. The diagram also shows the circulation cells; The Hadley cell found between 0-30 degrees N&S of the equator, air is heated at the equator rises and expands polewards, coriolis deflected the winds and they descend at 30 degrees forming a high pressure zone. Some of the air returns towards the equator as the trade winds. Meanwhile there is a deficit of solar energy at the poles cold air descends and the cold air is blown towards the equator as the polar easterlies. At 60 degrees the warm mid latitude westerlies which are transferring warn air from the tropics meet the cold polar easterlies at 60 degrees creating a polar front, where warm air is exchanged for cold air.