Atmosphere of Mars slowly decreased to very low concentrations, with no layer detectable above 35 km. The reporting scientists think that the observed polar ozone layers are the result of the same atmospheric circulation pattern that creates a distinct oxygen emission identified in the polar night and also present in Earth's atmosphere. This circulation takes the form of a huge Hadley cell in which warmer air rises and travels toward the south pole before cooling and sinking at higher latitudes. Mars is on a quite elliptical orbit and has a large axial tilt, which causes extreme seasonal variations in temperature amongst the northern
Controlled atmosphere so that the respiration is reduced. Under controlled atmosphere conditions the quality and the freshness of fruit and vegetables are retained, and many products can be stored for 2 to 4 times longer than usual. Franklin Kidd and Cyril West of Cambridge University did the basic research into fruit respiration and ripening leading to the first commercial facility in 1929. By 1960, there was capacity for 4 million bushels of apples in the US and by the 1980s, capacity exceeded 100 million bushels. Controlled atmosphere A controlled atmosphere is an agricultural storage method in which the concentrations of oxygen, carbon