atmosphere

• In the northern hemisphere the Hadley cell is formed between the equator and 30° north. The trade winds move air back southwest towards the equator. The ferrel cell is formed between 30° north and 60° north. The westerlies winds complete the cell by taking winds northeast. Winds are deflected to the right due to the corilis effect, which is caused by the spinning of the earth. Winds move from a area of high to low pressure, which creates the surface winds that transfer surplus energy from the equator to areas of deficit at the poles. When two air masses meet, warm air is forced to rise over cooler air. This happens at the ferrel cell, it is thermally indirect.  
• One reason for this is due to the curvature of the earth, in the tropics the sun rays are concentrated on much smaller areas resulting in more intense heating. Rays have less atmosphere to pass through at the tropics so less energy is lost through absorption and reflection. Albedo is the reflectiveness of land surface, darker forest surfaces at the tropics have a lower albedo so absorb more energy in contrast with lighter snow/ice covered areas at the poles. The tilt of the earth means limited insulation is received at the poles in the winter, whereas tropical areas receive insulation all year round.
• In the Atlantic Ocean current follow loops or gyres following clockwise in the North Atlantic. Warm currents travel from the equator towards to poles. For example the North Atlantic drift.  Cold currents return cool water from the poles. For example the Labrador current. Due to differential heating and salinity, density differences occur in water, resulting in chilled polar water sinking, spreading towards the equator and displacing warm water pole wards. The Coriolis effect deflects currents to the right in the northern hemisphere.  

    
• The tropical maritime is formed over the Atlantic Ocean. Its weather characteristics are warm , unstable air with high humidity and high precipitation. The tropical continental is formed over the Sahara desert. Its weather characteristics are very hot, stable air with low humidity and low precipitation. Poor visibility is caused by dust carried from the desert. 
• In the northern hemisphere winds are deflected to the right due to the corilis effect, which is caused by the spinning of the earth. The Ferrel cell is thermally indirect and the Hadley and polar cells are thermally direct. At the hadley cell warm air rises at the equator creating low pressure. The air splits in the atmosphere and moves towards the poles. Air cools and sinks at the tropics creating high pressure. The northeast trade winds move air back towards the equator completing the Hadley cell. The Ferrel cell is formed between 60° north and 30° north. The Ferrel cell transfers air between the Hadley and polar cells, forming the westerlies.