Abstract
While there are a lot of preceding studies dealing with relationships between urban heat islands and sea-breezes in the daytime, there only a few studies of those between nocturnal heat islands and sea and land breezes. The purpose of the present study is to clarify the influences of wind field structures on nocturnal temperature or nocturnal heat islands in the Osaka bay area in the summer season by analyzing some observational data including the doppler soda observational data. It is found that sea surface temperature contributes to increase daily minimum temperature in the Osaka bay area and that penetration of nocturnal land breeze or of nocturnal cool air mass into the area is important to lower nocturnal temperature.
