The composition of the atmosphere has undergone dramatic changes in the last decades due to human activities. The quasi-exponential growth in the world population and the industrialization have led to a strong growth in fossil fuel and biomass burning emissions of trace gases such as carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), methane (CH4), and other hydrocarbons. The emissions of nitrogen oxides and hydrocarbons have resulted in an increase of ozone (O3) near the surface and a degradation of air quality on a global scale. Although ozone is a trace gas and constitutes less than 0.001% of the air by volume, it is one of the most important constituents of the atmosphere. The ozone layer in the stratosphere protects the biosphere by absorbing harmful solar ultraviolet (UV) radiation. Downward transport of ozone from the stratosphere contributes to the ozone abundance in the troposphere, but ozone is also produced in the troposphere by sunlight driven chemical reaction cycles, involving NOx, CO, CH4 and other hydrocarbons. This can lead to excessive amounts of ozone near the surface (‘summer smog’), which are toxic to ecosystem, animals, and humans. Ozone in the tropical troposphere plays various important roles. The intense UV radiation and high humidity in the tropics stimulate the formation of the hydroxyl radical (OH) by the photolysis of O3. OH is the most important oxidant in the troposphere because it reacts with virtually all trace gases, such as CO, CH4 and other hydrocarbons. The tropopause, which separates the troposphere from the stratosphere, is higher ( 17km) and colder in the tropics, than at mid- and high latitudes. Since the radiative forcing by ozone is directly proportional to the temperature contrast between the radiation absorbed and the radiation emitted, ozone is most efficient as a greenhouse gas in the cold tropical upper troposphere.
USER DOCUMENTATION: ATBD
The Algorithm Theoretical Basis Document (ATBD) can be found by clicking here.
PUM & SAMPLE DATA
The Product User Manual (PUM) and Sample Data Files are being updated based on a new release of the processing software and will be available for download by mid-May 2017.
After launch, preliminary product results will be provided during the Commissioning Phase and the Operational Phase.