Ozone depletion as the International Day for the Preservation of the Ozone Layer, or "World Ozone Day", to commemorate the signing of the Montreal Protocol on that date in 1987. 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
Mixed layer determining the mixed layer depth is to examine the profile of potential temperature, the temperature which the air would have if it were brought to the pressure found at the surface without gaining or losing heat. As such an increase of pressure involves compressing the air, the potential temperature is higher than the in-situ temperature, with the difference increasing as one goes higher in the atmosphere. The atmospheric mixed layer is defined as a layer of (approximately) constant potential temperature, or a layer in which the temperature falls at a rate of approximately 10 °C/km, provided it is free of