pyranometer
pyranometer
(pĭr'ənŏm`ətər), actinometeractinometer, instrument used to measure the heating power of radiation. Actinometers are used chiefly in meteorology to measure solar radiation as transmitted directly by the sun, scattered by the atmosphere, or reflected by the earth.
..... Click the link for more information. used to measure the total radiation incident on a surface.
Pyranometer
an instrument for measuring the total and scattered solar radiation incident on a horizontal surface. To measure just scattered radiation, a screen is used to shade the instrument from direct sun rays.
In the USSR the pyranometer designed by lu. D. lanishevskii (see Figure 1) is extensively used. The radiation detector in a lanishevskii pyranometer is a thermopile consisting of series-connected manganin and constantan strips. The even-numbered junctions of the thermopile are covered with carbon black, and the odd-numbered with magnesia alba. Solar radiation is absorbed to a greater extent by the carbon black than by the magnesia. For this reason, a temperature difference arises between the junctions, and a thermoelectric current proportional to the incident radiation is generated. This current is measured by a galvanometer. A glass cap protects the thermopile from the effects of atmospheric infrared radiation, wind, and precipitation. In order to obtain the absolute values of the radiation, pyranometer is checked against an absolute pyrheliometer.
REFERENCE
lanishevskii, lu. D. Aktinometricheskie pribory i melody nabliudenii. Leningrad, 1957.T. V. EVNEVICH