Troposphere (IEK-8)

Water Vapour

For the study of the UTLS region that is of particular interest for water vapor, the dataset of the European research infrastructure IAGOS is particularly suitable due to its unique characteristics. IAGOS, together with its predecessor MOZAIC (Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft), is a global atmospheric composition observation system using autonomous instruments onboard a fleet of commercial passenger aircraft.

In addition to the processing, calibration, quality assurance and documentation of IAGOS water vapor measurement data, the tasks of the working group include the preparation of climatologies and trend analyses as well as the analysis of transport processes.

A focus is also on the investigation of the formation and persistence of contrails and their currently still largely unexplained influence on the climate, as well as the distribution of ice clouds and their long-term development using combined water vapor-cloud datasets.

Ozone

Ozone plays a unique role in the oxidative capacity of the atmosphere and acts as a potent greenhouse gas in the troposphere with a positive radiative forcing that is not offset by the radiative forcing of stratospheric ozone. The ozone distribution has a large heterogeneity, making it difficult to draw a global picture of current O3 concentrations and trends.

This was previously also complicated by the lack of ozone reference standards. Therefore, in 1996, the Environmental Simulation Facility at Forschungszentrum Jülich was established as the WMO World Calibration Center for Ozone Sondes (=WCCOS): a facility for quality assurance of ozone sondes used in GAW/GLONET, focusing on precision, accuracy and long-term stability of ozone sondes.