Thermally Direct/Indirect Cells
		q Thermally Direct Cells (Hadley and Polar Cells)      Both cells have their rising branches over warm temperature zones and sinking braches over the cold temperature zone. Both cells directly convert thermal energy to kinetic energy. q Thermally Indirect Cell (Ferrel Cell)      This cell rises over cold temperature zone and sinks over warm temperature zone. The cell is not driven by thermal forcing but driven by eddy (weather systems) forcing.