A Study on the Local Distribution of Cloud Nuclei (II)-Observations on the Sea between Tokyo and Chichijima Is. and at Mt. Fuji-
1972 Volume 23 Issue 3 Pages 183-196
Details
1972 Volume 23 Issue 3 Pages 183-196
Cloud nuclei and giant chloride nuclei observations were made in the fairly clean air-masses on the Pacific Ocean (from the Ogasawara Islands to Tokyo) and near the summit of Mt. Fuji in summer 1970.
On the ocean a cloud nuclei spectrum as function of supersaturation had a gentle slope up to 1% in supersaturation degree (S) and gradually approached a mean concentration of Aitken nuclei observed at the same time. The mean values of cloud and Aitken nuclei were respectively 75 per cubic centimeter at 0.3% in S and 450 per cubic centimeter.
Referring to the nucleus size distribution estimated from this spectral curve, it was elucidated that cloud nuclei about 0.01 micron in radius (corresponding to little more than 1% in S) were dominant if soluble nuclei were assumed.
The local distributions of cloud nuclei in Irozaki, Izu Peninsula and at the mountainside of Mt. Fuji (UCHIDA,1971) were compared with these observations in 1970. The former distributions show a steep slope in a range of more than 0.3% in S when compared with one of smaller percentage range, suggesting that the size distribution of (assumed) soluble cloud nuclei by inland pollution was dominant below 0.03 micron in radius.
On the ocean giant chloride nuclei, concentrations were fairly uniform everywhere,10 to 15 per liter in a mass larger than 1×10-9 gr in mild weather.
Near the summit of Mt. Fuji, NanagOhasshaku (3,400 m), the pattern of cloud nuclei spectrum was quite similar to that on the ocean. However, the Aitken nuclei concentration observed at the same time had a mean concentration about twice that on the ocean (i.e.,ca.830 per cubic centimeter). If soluble nuclei were assumed, the dominant cloud nuclei radius was estimated at about 0.01 micron as in oceanic observation.
Giant chloride nuclei were so scattered in concentration and fairly small in size, except for the rare cases of at most 1 to 3 per liter in masses of 1×10-11 to 3×10-10 gr near the summit (3,400 m). The ratios of concentration of cloud nuclei in 0.3% in S to Aitken nuclei were generally about 0.1 or so.
