Campaign

In order to understand the 3D-cloud effect there is a need for synergetic studies combining in-situ, satellite observations and model projections. Field experiments play an important role for this purpose. They allow key processes to be studied specifically, by using target observations and model setups. For example, cloud and aerosol properties can be obtained using remote sensing techniques. These measurements can then be used in Radiative Transfer Models. The calculated radiance and irradiance are then validated against observations at the surface and the top of the atmosphere.

Therefore, we will conduct a field campaign from April to September 2026. The measurements will take place at the Meteorological Observatory Lindenberg – Richard Aßmann-Observatory as well as the DWD measurement site in Falkenberg (Tauche).

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, short- and longwave radiometers and cloud cameras. These instrument are depicted in the figure below. 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.

The DWD measurement site in Falkenberg will host a cloud radar, a microwave radiometer, a ceilometer, a wind lidar, a sun photometer, a broadband radiation station, cloud cameras, and further measurement devices (see below). Additionally, the Falkenberg site will serve as a base for various airborne measurements.

Furthermore, a network of pyranometers will be set up. The network will have its highest density at the observatory in Lindenberg and the measurement site in Falkenberg, but will extend over an area of almost 10 by 10 km.

Further scientific partners are welcome to take part at the campaign. All instruments being deployed at the C3SAR field campaign are listed further below.

The chosen time period for the field campaign allows to capture the lowest solar zenith angles. During this time of the year, convective, mainly liquid cumuli clouds are normally predominant. However, towards the end of the campaign, the likelihood for stratiform clouds in conjunction with low pressure systems increases and hence offers the possibility to include such cloud scenes as well.

Beyond the described ground-based measurements, 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.

This field campaign makes it possible to create an unique dataset. High-resolution modelled, reconstructed, and observed data on radiation and clouds will be combined. 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. These efforts will also help to study how clouds affect shortwave and longwave radiation in 3D. Finally, the results will be used to correct errors in climate models and satellite-based cloud measurements.

Our field campaign does not only focus on research as it will also host a summer school. Members of this Research Unit as well as invited guests will give workshops and lectures. The summer school will be open for all interested PhD on the topics of clouds, aerosols, and radiation.