KIT researchers set up and manage the thematic center CIS for the direct measurement of cloud processes – part of the European research infrastructure ACTRIS

Clouds play an important role in the earth’s climate system. Through Europe-wide measurements, the thematic center CIS will create a broad database to better understand the influence of cloud properties on the climate. The multinational consortium led by the Karlsruhe Institute of Technology (KIT) is part of the European research infrastructure ACTRIS for the long-term observation of aerosols, clouds and trace gases.

“Clouds transport water and bring precipitation, they cool the earth by reflecting incident sunlight, and envelop our planet like a blanket that prevents heat from being dissipated into space,” says Dr. Kristina Höhler. The chemist and her colleague, the physicist Dr. Ottmar Möhler, both working at the KIT Institute for Meteorology and Climate Research in the Department of Atmospheric Aerosol Research (IMK-AAF), head the newly founded thematic center CIS (stands for Cloud In-Situ Measurements) within ACTRIS (stands for The Aerosol, Clouds and Trace Gases Research Infrastructure); the CIS will begin its work in 2021.

“The CIS is one of the six thematic centers that specialize in remote sensing and on-site studies of aerosols, clouds and trace gases. They form the heart of the pan-European ACTRIS infrastructure, ”says Höhler. The CIS infrastructure will be built over the next five years in order to coordinate the Europe-wide direct measurement of cloud properties.

The two KIT researchers have been investigating aerosol cloud processes for years and use, among other things, the cloud simulation chamber AIDA (stands for Aerosol Interaction and Dynamics in the Atmosphere) on the KIT Campus North, which is unique in Germany. The management of the CIS was entrusted to Höhler, institute manager of the IMK-AAF, and Möhler, head of the research group Aerosol Cloud Processes, from the Interim ACTRIS Council (IAC), a committee made up of representatives from ministries and funding organizations.

Quality assurance and comparability of data

The radiation balance of clouds – the heating and cooling – is influenced by their height in the atmosphere, the number of their particles and the ratio of water droplets and ice they are made of. The global rise in temperatures can cause clouds to form at other altitudes or less or more cloud ice to form. “In order to better understand the exact influence of cloud properties on our climate and to be able to make good predictions, long-term observations of high quality and measurement accuracy are important,” emphasizes Höhler. In addition to monitoring the observation stations, one of the main tasks of the CIS will be to ensure the quality and comparability of data collected in the observatories, mobile measuring platforms and laboratories. In order to calibrate and standardize measuring devices, a further smaller cloud simulation chamber is to be built at KIT. The CIS supports the operation of the national ACTRIS facilities and offers, among other things, training courses and seminars for the participating scientists.

Long-term observation for improved climate models

“It is our aim to support and coordinate the establishment of numerous national measuring stations across the country,” says Höhler. The measurements and investigations into the influence of clouds on the climate over the years are intended to collect regional and seasonal data. This enables climate models to be improved and further developed. The insurance industry will also be able to use information, for example, to better predict the probability of extreme weather events. It is planned to make the results of the long-term observations available to authorities, political decision-makers and the interested public in an open database.

In addition to the lead KIT, the CIS consortium includes the Leibniz Institute for Tropospheric Research in Leipzig, the Sonnenblick Observatory in Austria and the University of Manchester in Great Britain.

Details on the KIT Climate and Environment Center:

As “The Research University in the Helmholtz Association”, KIT creates and imparts knowledge for society and the environment. The aim is to make significant contributions to the global challenges in the fields of energy, mobility and information. To this end, around 9,300 employees work together on a broad disciplinary basis in the natural, engineering, economic, humanities and social sciences. KIT prepares its 24,400 students for responsible tasks in society, business and science through a research-oriented university course. The innovation activity at KIT bridges the gap between knowledge and application for social benefit, economic prosperity and the preservation of our natural foundations of life.