Investigating clouds and precipitation at the Jülich Observatory for Cloud Evolution

 

Authors

Susanne Crewell — University of Cologne
Kerstin Ebell — University of Cologne
Ulrich Loehnert — University of Cologne
Birger Bohn — Research Centre Juelich

Category

Infrastructure & Outreach

Description

The Jülich Observatory for Cloud Evolution (JOYCE) is a unique site for investigating the processes leading to cloud formation and cloud evolution. To this end, various instruments have been set up at the Research Centre Jülich that continuously monitor water vapour, clouds, and precipitation over many years. JOYCE is operated jointly by the University of Cologne, the Research Centre Jülich, and the Transregional Collaborative Research Centre TR32 “Patterns in Soil-Vegetation-Atmosphere-Systems: Monitoring, Modelling and Data Assimilation.” The area around Jülich (Germany) is arable land characterized by heteorogenous land surface conditions that are monitored by TR32.

The core instruments of JOYCE are a scanning cloud radar, a micro rain radar, a ceilometer, a pulsed Doppler lidar, a scanning 14-channel microwave radiometer (MWR), an infrared spectrometer (AERI), a Doppler sodar, a total sky imager, and radiation sensors. These measurements are supplemented by the standard meteorological measurements from the 120-m measurement tower including eddy covariance and in situ aerosol measurements. In addition, the polarimetric weather radar of the Research Centre Jülich provides information about the spatial distribution of precipitation. Because aerosol and precipitation vary rapidly in the area of Jülich, the long-term data cover a broad atmospheric spectrum well-suited for process studies and statistical analysis. For the latter, synergetic products based on the integrated profiling techniques (Lohnert et al. 2008) are derived.

In addition to the continuous monitoring of the atmospheric column, a 3D picture of water vapour and clouds is provided by the hemispheric scans of the cloud radar and MWR. The data of TR32 and JOYCE are used to investigate the influence of the land surface on surface on water vapour variations, the development of boundary clouds, cloud radiation interaction, and the precipitation formation.