a) A cell of dry air is moved vertically from its original position under adiabatic conditions. Depending on the temperature profile of the surrounding atmosphere, this gas cell can keep on moving in the same direction, or it may come back to its original position. Considering the temperature profile of the atmosphere, change of the air cell temperature as it moves up and down in the surrounding atmosphere, as well as relative densities of the air cell and atmosphere, explain why and when the atmosphere is considered to be convectively stable and convectively unstable. In answering this question, use diagrams of temperature change with altitude. (13 marks) b) Explain why the adiabatic lapse rate of dry air is different from the adiabatic lapse rate of wet saturated air. Show them both in a diagram. (5 marks) c) Wet unsaturated air rises from the ocean surface. The ambient lapse rate is higher than the adiabatic lapse rate for dry air. There is a temperature inversion layer at higher altitudes. Show in a schematic diagram how the temperature of the wet air changes with altitude, in comparison with the ambient temperature. Explain at what altitudes the cumulus clouds are formed and why. (7 marks)
