The device consists of a solid, lightweight metal measuring body with two drying containers and a handle. The two blackened receiver surfaces are located on the top and bottom of the measuring body. Each of the receiver surfaces is shielded by a Lupolen dome and sealed watertight by a screw ring and O-ring. Two circular bubbles are used for horizontal alignment. The heavy-duty construction of the housing gives the pyrradiometer considerable thermal inertia.
Each pyrradiometer is equipped with a Pt100 electrical resistance thermometer for measuring the block temperature. This temperature is the reference temperature for measuring the radiation fluxes from the upper and lower hemispheres. Since these radiation fluxes are measured thermoelectrically, i.e., based on the measurement of a temperature difference, the reference temperature for the inactive solder joints must be known—the block temperature. It may differ from the ambient temperature in certain cases. If only the radiation balance is to be measured, the block temperature need not be determined.
