General aspects of land and sea breezes in Osaka Bay and surrounding area

Abstract

The general aspects of land and sea breezes in the Osaka Bay area and its environment are revealed from an analysis of the wind data obtained by the AMeDAS. The study area consists of a complex land-sea configuration and a complex topography which includes plains, hilly terrain, and mountainous regions. The land and sea breezes are classified into five types according to the behavior of the sea breeze at several locations in the study area. The most frequently occurring type is characterized in the following. Along the southern coast of Osaka Bay, the s e a breeze from Osaka Bay changes with time into that from the Kui Channel. At the same time, along the coast of the Seto Inland Sea the sea breeze contains a predominant easterly component. For this type, several interesting features are further elucidated: (1) the simultaneous onset of the coastal sea breeze and the valley or upslope wind in the mountainous region is clearly seen, especially in the eastern Chugoku area, (2) the meeting of the southerly sea breeze from the Seto Inland Sea and the northerly breeze from the Sea of Japan occurs around the region of the mountain ridges in eastern Chugoku, (3) the alternation of converging sea breezes from surrounding seas forms a uniform southerly sea breeze from the Kui Channel at Awaji Island, (4) the southerly sea breeze continues until the late afternoon in the coastal area of the Kui Channel and Osaka Bay. Other types are discussed and compared with the above type for the mature stage of the sea breeze. The relationships between the occurrence of the land and sea breeze and general meteorological conditions are also analyzed. © 1995, Meteorological Society of Japan.