The three environmental themes covered by TROPOMI are Air Quality, Stratospheric Ozone Layer and Climate Change Monitoring and Forecasting.
At the Earth's surface, aerosols, ozone and other reactive gases such as nitrogen dioxide determine the quality of the air around us, affecting human health and life expectancy, the health of ecosystems and the fabric of the built environment. Ozone distribution in the stratosphere influence the amount of ultraviolet radiation reaching the surface. Dust, sand, smoke and volcanic aerosols affect the safe operation of transport systems and the availability of power from solar generation, the formation of clouds and rainfall, and the remote sensing by satellite of land, ocean and atmosphere.
To address these environmental concerns there is a need for data and processed information. The http://atmosphere.copernicus.eu/ (CAMS) has been developed to meet these needs, aiming at supporting policymakers, business and citizens with enhanced atmospheric environmental information.
The climate change theme is relevant to the http://climate.copernicus.eu/ (C3S). The service, currently in development, provides access to several climate indicators (e.g. temperature increase, sea level rise, ice sheet melting, warming up of the ocean) and climate indices (e.g. based on records of temperature, precipitation, drought event) for both the identified climate drivers and the expected climate impacts.
Air is essential to life, with substances dangerous to human and animal health as well as plant life, natural causes such as vegetation, fires, volcanic eruptions, alongside human activities like traffic and industrial productions can have a significant impact to the molecules and chemical reactions in the atmosphere. Gases like sulfur dioxide (SO2), formaldehyde (HCHO) and nitrogen oxides (NOx) can have a direct impact to human health, causing illness and even having carcinogenic properties, even excessive amount of ozone in the troposphere by sunlight driven chemical reaction cycles, involving NOx, CO, CH4 can become toxic to the ecosystem.
Aerosol Index (AER_AI) and Layer (AER_LH) can also be used to detect presence of both UV-absorbing aerosols like dust and smoke, as well as non-absorbing aerosols including sulfate aerosols.
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 men.
The main Sentinel-5P products relevant for Ozone monitoring are the O3 family (O3, O3_TCL and O3_PR), but studying the Nitrogen Dioxide (No2) can also be useful as NO2 is involved in some photochemical reactions with ozone and thus affects the ozone layer.
Our climate is undergoing change more rapid than at any other point since the end of the last ice age, 10000 years ago. The extent remains uncertain but its direction is clear: the world is heating up, and it appears to be due to our actions. Earth observation has the potential to improve our predictive vision, TROPOMI multispectral imaging spectrometer does measure other greenhouse gases such as methane (CH4) a potent greenhouse gas, trapping about 30 times more heat per mass unit than carbon dioxide. Sentinel-5P also measures aerosols (AER_AI, AER_LH) and clouds (CLOUD), which affect Earth’s radiation balance. Many Sentinel-5P products can be used for climate change monitoring and understanding, Nitrogen dioxide (NO2), for example, while being a minor greenhouse gas in itself, the indirect effects of NO2 on global climate change are probably larger, with a presumed net cooling effect mostly driven by a growth in aerosol concentrations through nitrate formation from nitrogen oxides and enhanced levels of oxidants; Sulfur dioxide (SO2) has an effect on climate through radiative forcing, via the formation of sulphate aerosols; Formaldehyde (HCHO) supports several reactions that can lead eventually to Carbon Dioxide (CO2) one of the main greenhouse gases, Ozone (O3) is strongly linked to climate due to its influence on Earth’s radiative budget, absorbing solar UV radiation in the stratosphere and terrestrial infrared radiation in the troposphere, lastly, Carbon Monoxide (CO) is also a weak greenhouse gases in itself, but it also contributes in chemical reactions that produce Ozone.
TROPOMI is a huge asset for supporting aviation control services during volcanic eruptions. The S5p sensor TROPOMI samples the Earth’s surface with a revisit time of one day and with an unprecedented spatial resolution. This allows the resolution of fine details and S5p to arguably be a valuable tool to better study anthropogenic SO2 emissions but also volcanic emissions, from degassing to eruptive processes. The Aerosol products (AER_AI / AER_LH) can also be used to track episodic aerosol plumes such as volcanic ash, desert dust and smoke from biomass burning.