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 Controlled atmosphere A controlled atmosphere is an agricultural storage method in which the concentrations of oxygen, carbon dioxide and nitrogen, as well as the temperature and humidity of a storage room are regulated. Both dry commodities and fresh fruit and vegetables can be stored in controlled atmospheres. Grains, legumes and oilseed are stored in a controlled atmosphere primarily to control insect pests. Most insects cannot survive indefinitely without oxygen or in conditions of raised (<30%) carbon dioxide. Such controlled atmosphere treatments of grains may take several weeks at lower temperatures (<15 °C). A typical schedule for complete disinfestation of dry