C3SAR
Cloud 3D Structure and Radiation
Science
The main goal of the Research Unit C3SAR is to better understand the role of 3d cloud variability. Furthermore, we want to provide robust tools in cloud remote sensing and cloud radiative forcing parameterization that account for 3d radiative effects in a feasible and realistic manner. Thereby, we will combine the research expertise on cloud resolving atmospheric and radiative transfer modelling as well as ground- and satellite based remote sensing and radiative flux observations. This cooperative approach can provide the required data, methodologies and tools to realistically account for 3d radiation transports. Thus, C3SAR will, for the first time, allow us to correct biases in climate modelling and cloud remote sensing, that have been a result from oversimplifications of the complex geometrical nature of clouds.
To do this, the team will use typical three-dimensional cloud shapes from detailed cloud modelling and synergistic satellite observations. These shapes will be used in radiative transfer models of different complexity to quantify the consequences of cloud structure simplifications and to establish physically based cloud-radiation correlations. Long-term, high-quality ground-based observations of clouds and radiation provide the validation of these relations by means of radiative closure studies. Both current and new generations of satellite sensors will provide the corresponding closure at the top of the atmosphere.
C3SAR is a DFG-funded research unit. The contributing partners are
- University of Cologne
- Leibniz Institute for Tropospheric Research
- Ludwig Maximilians University Munich
- Leibniz University Hanover
- German Weather Service
The work within C3SAR is organized within five scientific projects. These are:
- P1: Modelling cloud micro- and macrophysical properties and their radiative effects
- P2: Cloud structure and regime dependencies of 3D radiative effects
- P3: Cloud radiative effects from ground-based vertically resolved cloud & radiation observations and radiation closure
- P4: Satellite-based cloud remote sensing & 3d effects
- P5: Synergetic field observations & modelling
Campaign
In summer 2026 we will conduct a three-month field campaign at the Lindenberg Observatory. Thereby, modelling, ground-based measurements, in-situ radiation measurements and satellite observations will be performed. This combined study will validate our ability to observe, understand, and model the cloud radiative effects and thus to reduce a major source of uncertainty in predicting the future climate.In summer 2026 we will conduct a three-month field campaign at the Meteorological Observatory Lindenberg – Richard Aßmann-Observatory. The observatory provides a wide range of routine ground-based measurements. Among these are cloud radars, ceilometers, microwave radiometers, a Raman Lidar, radiosounding, an infrared hemispherical sky imager, and short- and longwave radiometers. This setup will be complemented by a small-scale pyranometer network from TROPOS to better capture the spatial variability of the solar irradiance at the surface. Additionally, the novel in-situ instrument AMUDIS from the Leibniz University Hanover will be deployed. This instrument allows to measure spectrally and temporally highly resolved radiances. Further scientific partners are welcome to take part at the campaign.
Beyond this, we will benefit from the availability of the newest generation of satellite-based measurements from Meteosat Third Generation and EarthCARE. The corresponding observations will offer unprecedented capabilities in the observation of cloud evolution and measurements of the 3D cloud fields and their corresponding radiative effects at the top of the atmosphere.
A unique data set will be created by combining high-resolution modelled, reconstructed, and observed data on radiation and clouds. This data set will include cloud properties, as well as irradiance and radiance at the Earth’s surface and at the top of the atmosphere. We will use this dataset for comprehensive cloud regime-based radiation closure experiments with 1D and 3D radiative transfer models. The goal is to reproduce the observed spatiotemporal statistical properties of spectral irradiance and spectral radiance at the surface and at the top of the atmosphere.
Outreach
Lastest Media Report:
07 February 2025
Für bessere Wetterberichte: Experten vom Tropos-Institut Leipzig wollen Wolken neu vermessen
Klimaforscher vom Tropos-Institut in Leipzig und aus ganz Deutschland wollen bessere Wetter- und Klimamodelle ermöglichen. Sie arbeiten jetzt in der Forschungsgruppe C3SAR zusammen.
Latest Press Release:
30 January 2025
30.01.2025: Wolken in 3D sollen Klimamodelle deutlich verbessern
Klimaforschende aus Deutschland wollen in den nächsten Jahren einen Durchbruch bei den Strahlungseigenschaften von Wolken erreichen, indem sie die entsprechenden Prozesse nicht wie bisher nur eindimensional, sondern künftig dreidimensional beschreiben. Wolken und Strahlung in 3D zu erfassen, gilt als wichtiger Schritt zu einer unverzerrten Fernerkundung der Atmosphäre sowie zu einer verbesserten Modellierung von Klima und Wetter. Mit dem Auftaktreffen Ende Januar in Leipzig am Leibniz-Institut für Troposphärenforschung (TROPOS) wird die Arbeit in diesem bedeutenden Thema gestartet.
Contact
Coordinator of the Research Unit C3SAR:
Dr. Jörg Schmidt
Leibniz Institute for Tropospheric Research
Permoserstrasse 15, 04318 Leipzig
+49 (0)341 2717 7497
Speaker of the Research Unit C3SAR:
Prof. Dr. Andreas Macke
Leibniz Institute for Tropospheric Research
Permoserstrasse 15, 04318 Leipzig
+49 (0)341 2717 7060