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Short-lived trace substances

Spokesperson: Dr. Mariano Mertens

Besides long-lived trace gases such as methane with lifetimes of several years, many other trace gases with much shorter lifetimes exist. Ozone, nitrogen oxides, carbon monoxide, sulfur dioxide, or non-methane hydrocarbons are examples of short-lived trace gases. All of them have lifetimes between hours, days, and several weeks. Some of these trace gases, such as ozone, directly affect the radiation balance of the Earth's atmosphere and thus the climate. Others, such as nitrogen oxides, can lead to the formation of radiatively active trace gases such as ozone. Furthermore, short-lived trace gases determine the oxidation capacity of the atmosphere via their influence on hydroxyl radicals and thus impacting the photochemical lifetime of e.g. methane and sulphur dioxide. Further, short-lived trace gases also have an indirect influence on the chemical formation of water vapour in the Stratosphere trough their impact on the methane oxidation.

The aim of this matrix group is to bundle the various methodical capacities of the institute and use the synergies to deepen our understanding on the topic of short-lived trace substances. Our research is embedded in the DLR programmes Space, Aeronautics and Transportation and the focus is on the following scientific questions:

• How large is the (indirect) climate impact of short-live trace gases?
• What is the influence of short-lived trace gases on the oxidation capacity of the troposphere and on the lifetime of methane and SO₂?
• What are promising mitigation options when dealing with air quality and climate mitigation targets simultaneously?

These research questions are tackled with a broad spectrum of methods. The following research tools are available for this purpose:

• Aircraft-based in-situ measurements
• Remote sensing data (e.g. from the satellite mission Sentinel-5P),
• Global and regional models.