On the Distribution of Cloud in the Sky at Toyohara Sakhalin. (First Report)

Abstract

Sketches of the clouds in the whole sky at Toyohara were made at 10h. and 14h. every day from Nov. 1932 to Dec. 1933 by the members of the Toyohara Magnetic Observatory. The author of the present paper investigated statistically the distribution of cloud amount in every part of the sky using these sketches. The annual and seasonal distribution, the distribution for 10h. and 14h., for every case of lower cloud directions, etc. were illustrated by figures. Generally the cloud amount is great near the horizon or mountain-ranges and small near the zenith, but the directional difference near the horizon and the azimuthal displacement of least cloud amount area is seen for respective eases. The difference between 10h. and 14h. is large over the area of the town of Toyohara. This may be caused by the local ascending current of thermal origin. The least cloud amount area near the zenith displaces to leeward side for every four cloud directions. This may be the effect of the local ascending and descending current caused by the greater resistance of the town for the motion of air.