Research topic: ozone
The ozone layer protects against UV radiation and has also influence on the climate change.
Selected contributions to the "research topic: ozone" (O3) are presented by scientists from the Forschungzentrum Jülich (FZJ), the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and the Karlsruhe Institute of Technology (KIT). For more information, follow the respective links.
Changes in the ozone distribution in the stratosphere therefore have direct effects not only on the intensity of UV irradiation of the Earth’s surface but also on the thermal structure of the stratosphere and thus on the global climate system. At the same time, changes in atmospheric circulation and the emission of anthropogenic substances impact the ozone layer. It is thus an integral part of the global climate system, and a detailed understanding of the processes which regulate the distribution of ozone in the atmosphere is fundamental for correct climate prediction and the prediction of future UV load on the biosphere.
These weather balloons, filled with hydrogen or helium, attain speeds of 5 m/s and altitudes of up to 35 km before they burst. A roughly 60 m long cord is attached to the rubber balloons. A radiosonde with sensors for air pressure, humidity and temperature and an ozone sonde are fitted to the end of the cord. During its ascent the sonde transmits the measured values by radio to the receiving station on the ground, where they are collected, analysed and input into global scientific networks.
More on measurering the concentration of ozone»
Measurements of the ozone layer are an important component of ozone layer monitoring, but not the only one. Ozone measurements are also conducted from the ground, from aircraft (from both special research aircraft and airliners) and from satellites.
For about 50 years the emission of chlorinated and brominated substances (in particular hydrochlorofluorocarbons and halons) due to human activity has resulted in a thinning of the ozone layer. The ozone loss is very low in the tropics and is today roughly 3.5% on a global average. By far the largest ozone loss has occurred every year since about 1980 in the austral spring, during which time roughly two-thirds of the entire ozone column above the Antarctic are lost. This severe ozone depletion is referred to as the "ozone hole".
More on model simulations: prediction of changes in the ozone layer»
Under the influence of long-lived air pollutants that are first really activated by low temperatures the protective ozone layer can be extensively destroyed towards the end of the cold polar winter. At the same time the returning sun triggers a chain of complex chemical reactions that break down ozone. In considerably colder Antarctica this process regularly leads to the formation of an ozone hole in the Antarctic spring.
More on first Arctic ozone hole form in spring 2011»
For the actual winter 2014/2015, stratospheric temperatures were relatively warm, such that the ozone loss in this year is expected to be rather low. If the temperatures would decrease significantly over the remaining course of this winter or in future winters, there would be larger ozone losses. These calculations would then serve as an early-warning system.
More on ozone loss in the Arctic stratosphere»
Apart from protecting the Earth from the Sun's ultraviolet radiation ozone can be a greenhouse gas as well. It is mainly formed in the tropical stratosphere and subsequently transported to the poles. Under increased CO2 concentrations this so called Brewer Dobson circulation accelerates a ubiquitous feature in climate model. The new study however highlights the fact that in an accelerated circulation less ozone is been formed resulting in a local decrease of ozone and a significant cooling of the lower and middle tropical stratosphere of up to 3.5 °C. An important feedback resulting from this temperature decrease is a relative drying of the stratosphere. Water that is contained in the rising air freezes in the tropopause region at around 18 km height, creating cirrus clouds. These again amplify the tropospheric cooling due to increased albedo.
More on the key role of ozone in climate change»
Scientists of the Forschungszentrum Jülich (FZJ) and of the Rhenish Institute of Environmental Research at the University of Cologne (RIU) are calculating the level of air pollution for Germany and Central Europe on a daily basis and produce flow animations to show concentrations of NO2, ozone and PM10.
More on Real time data and forecasting: air pollution in Europe»