S^os'Z^ f^J^S"^, JU/^a /8 . / 9^4 . 



Fig. 3. 



fogs being observed in the area to the south of Central Kuriles, where 

 the Oya Shio is the most predominant. Usually sea fogs are carried 

 in over coastal districts. 



(2) Moderate breeze is most favourable to the formation of sea 

 fogs, the direction of wind being between south-east and south-west. 



(3) When the sky is overcast with low or middle cloud, fogs are in 

 many cases dense and stable, and sometimes are maintained for several 

 days or more throughout day and night. 



(4) When the sky is cloudless or partly clouded, or covered with high 

 cloud, fogs are usually thin in the daj^time on account of receiving solar 

 radiation and remain off the coast, but in the evening or at night they 

 become dense and spread over coastal districts, where they dissolve the 

 next day. Moreover, very thin fogs disappear entirely even at sea in 

 the daytime and form again in the evening. 



(5) Very often sea fog forms at some distance above sea-level. Such 

 fog is usually called stratus, though there is no fundamental difference 

 between them. In the opinion of the present author such stratus is but 

 a special state of sea fog, and accordingly it is better to call it, for 

 example, " high-base sea fog." But here " stratus " shall be still used 

 according to the custom (see Fig. 4). 



Sea fog changes frequently into stratus as it dissolves from below or 

 its base rises above sea-level (mostly in daytime), and reversely stratus 

 changes into fog as it builds down to sea-level or to the ground (mostty 

 at night). 



(6) Sometimes fog or stratus is formed of two or three different 

 layers in piles. Such a single layer often changes into double or triple 

 layer, and reversely double or triple layer often changes into single layer 

 (see Figs. 5 and 6). 



72 



