Multi-channel Microwave Radiometer

The contract is for the purchase of a Multi-channel Microwave Radiometer.

Based on a market survey, only one supplier can provide a system that meets all of the minimum requirements. The market survey consisted of internet searches, discussions with colleagues at EU-funded COST action PROBE, the European Space Agency, the European Research Infrastructure for Aerosols, Clouds and Trace gases (ACTRIS), searches in the scientific literature and discussions with manufacturers at scientific meetings. ACTRIS is a pan-European distributed research infrastructure making long-term measurements of aerosol, clouds and trace gases at atmospheric observatories. The multi-channel microwave radiometer will form part of FMIs contribution to this observation network, specifically the cloud profiling network, and will be deployed permanently in Kenttärova (Pallas). To belong to this observation network, the instrument must meet the specifications of the European-wide ACTRIS network. The multi-channel microwave radiometer must also fulfil the scientific goals of FMI. The multi-channel microwave radiometer is required to derive zenith-pointing integrated liquid water (liquid water path) with RMS accuracy < 0.03 kg m-2 and water vapour (water vapour path) with RMS accuracy < 0.3 kg m-2 at a temporal resolution < 5 s in order to capture short-term fluctuations in liquid water path (matching or exceeding the ~3 s temporal resolution of a co-located Doppler cloud radar). Multiple channels (more than 2) are required to perform inter-channel consistency checks. The instrument must also have humidity and temperature profiling capability, for instance using elevation scanning in two microwave bands (K-band for humidity, V-band for temperature). The instrument must demonstrate a receiver temperature stability < 30 mK and provide the brightness temperatures as one of the outputs so that instrument performance and stability can be monitored as per ACTRIS network requirements. The instrument must also be a fully passive system so that it does not influence other sensitive receivers operating in the microwave region in the same location. No other commercial instrument operates with sufficient temporal resolution, is fully passive and provides humidity and temperature profiling together with the zenith-integrated values for liquid water and water vapour with the accuracies stated.