TRANSMITTANCE OF TOTAL SOLAR-RADIATION AN D OPTICAL DEPTHS OF LOW-LEVEL CLOUDS AS INFERRED FROM DATA OF THE ZVENIGOROD EXPERIMENT IN 1994

The transmittance (C-Q) of total solar radiation through overcast low- level cloud cover in the integral, ultraviolet, and photosynthetically active spectral regions was analyzed from actinometric observations m ade during the Zvenigorod experiment in 1994. Optical depths tau of lo w clouds were calculated and compared with those determined from long- term measurements at the Meteorological Observatory of Moscow State Un iversity. The magnitudes of total integral radiation measured with a t hermoelectric M-80 pyranometer were compared with those measured with an Eppley pyranometer.