Ozone as concentrations in μg/m. The study of ozone concentration in the atmosphere started in the 1920s. The highest levels of ozone in the atmosphere are in the stratosphere, in a region also known as the ozone layer between about 10 km and 50 km above the surface (or between about 6 and 31 miles). However, even in this "layer", the ozone concentrations are only two to eight parts per million, so most of the oxygen there is dioxygen, O, at about 210,000 parts per million by volume. Ozone in the stratosphere is mostly produced from short-wave ultraviolet rays between 240
Free convective layer (MPL). Free convective layer In atmospheric sciences, the free convective layer (FCL) is the layer of conditional or potential instability in the troposphere. It is a layer of positive buoyancy (PBE) and is the layer where deep, moist convection (DMC) can occur. On an atmospheric sounding, it is the layer between the level of free convection (LFC) and the equilibrium level (EL). The FCL is important to a variety of convective processes and to severe thunderstorm forecasting. It is the layer of instability, the "positive area" on thermodynamic diagrams where an ascending air parcel is warmer than its environment. Integrating