The radiation balance meter is a device for the direct and immediate determination of the radiation balance of a surface in the wavelength range from 0.3 to > 30 μm. The radiation balance is the difference between the radiation energy incident on a unit area of the Earth's surface and the radiation energy emitted by this surface into the upper hemisphere.
Measuring principle:
Measurement of the temperature difference between upward- and downward-facing blackened receiver surfaces using thermocouples. The upper receiver surface measures the shortwave global radiation and the longwave radiation of the atmosphere according to their temperature. The lower receiver surface measures the reflected shortwave radiation and the longwave radiation according to the surface temperature of the subsurface.
To directly determine the radiation balance, the two receiver surfaces are electrically connected in opposite directions.
The positive sign indicates radiation fluxes directed toward the Earth's surface, meaning that the reference surface gains radiation energy. If the sign of the radiation balance is negative, radiation energy is withdrawn from the reference surface.
Description
The radiation-sensitive part of the device is the thermopile built into the center section. It consists of thermocouples and is covered by two blackened "receiving surfaces." These, in turn, are shielded from the outside by two domes made of "Lupolen" (a plastic with the necessary optical properties). Two cover rings and flat gaskets tightly seal the sensor. Two bubble levels allow adjustment to the horizontal operating position.
A removable container for the dry substance (silica gel) is attached to the side of the sensor in such a way that it does not create any shielding from the upper or lower half of the sensor. An approximately 400 mm long support tube allows for easy handling.
