ASMUWARA, a ground-based radiometer system for tropospheric monitoring

ASMUWARA, the All-Sky MUlti WAvelength RAdiometer, is a new ground-based and automatically operating radiometer system designed for tropospheric monitoring. ASMUWARA has ten channels in the microwave and infrared range and is able to observe the sky in all directions with an angular resolution of 9 degrees. No radome is used to allow an optimum view quality at all wavelengths. The purpose of ASMUWARA is to retrieve temperature and humidity profiles, maps of integrated water vapour and liquid water, and additional cloud properties. The construction and characteritics of ASMUWARA are described. Special emphasis is put on the calibration loads, the calibration method, and the correction of antenna beamwidth effects.