Ozone depletion Ozone depletion Ozone depletion describes two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere (the ozone layer), and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events. The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting
Convective Boundary Layer and moisture. (3) The Entrainment zone (or Capping inversion) can be quite thick, averaging about 40% of the depth of the CBL. It is the region of statically stable air at the top of the mixed layer, where there is entrainment of free atmosphere air downward and overshooting thermals upward. Potential temperature and wind speed have a sharp increase across the capping inversion, while moisture has a sharp decrease. CBL depth has a strong diurnal cycle with a 4-phase process growth (1) Formation of a shallow mixed layer : During the early morning the mixed layer is shallow and its