Cloud liquid measurement with a ground-based microwave instrument

We describe the design of a new instrument developed to measure the integrated liquid content in clouds. The system simultaneously measures the absorption of a 28-GHz coherent signal transmitted from the Comstar 3 synchronous satellite and the associated increase in brightness temperature radiated by the absorbing clouds by means of a bandwidth-switched receiver. By combination of the two quantities the line integral of the cloud liquid is obtained. Examples of absorption events observed during the first six months of operation are presented.