JOYCE: Jülich Observatory for cloud evolution

The Jülich Observatory for Cloud Evolution (JOYCE), located at Forschungszentrum Jülich in the most western part of Germany, is a recently established platform for cloud research. The main objective of JOYCE is to provide observations, which improve our understanding of the cloudy boundary layer in a midlatitude environment. Continuous and temporally highly resolved measurements that are specifically suited to characterize the diurnal cycle of water vapor, stability, and turbulence in the lower troposphere are performed with a special focus on atmosphere–surface interaction. In addition, instruments are set up to measure the micro- and macrophysical properties of clouds in detail and how they interact with different boundary layer processes and the large-scale synoptic situation. For this, JOYCE is equipped with an array of state-of-the-art active and passive remote sensing and in situ instruments, which are briefly described in this scientific overview. As an example, a 24-h time series of the evolution of a typical cumulus cloud-topped boundary layer is analyzed with respect to stability, turbulence, and cloud properties. Additionally, we present longer-term statistics, which can be used to elucidate the diurnal cycle of water vapor, drizzle formation through autoconversion, and warm versus cold rain precipitation formation. Both case studies and long-term observations are important for improving the representation of clouds in climate and numerical weather prediction models

Area dose measurements by thermoluminescence dosemeters for environmental monitoring

For more than 25 years, thermoluminescence dosemeters (TLDs) have been used at Research Centre Julich for the dose determination of photon radiation in environmental monitoring. Dose measurements are performed in six-month exposure intervals at 78 measuring locations in total at the outer fence and some additional locations inside and outside the research centre. Long-term variations in natural background radiation are analysed in comparison with climate data and the local conditions near the measuring locations and discussed with a view to determining the area-specific parameters. Taking the special conditions of Research Centre Julich into account, the problems relating to the detection limit of 0.1 mSv/a, stipulated in the guideline for the emission and immission monitoring of nuclear facilities, are considered in more detail compared to natural background radiation