Behaviors of land and sea breeze above Fukuoka City

Climate change due to urban growth for 100 years and behaviors of land and sea breeze for l8 years have been investigated for Fukuoka City area. Change of population and meteorological data shows that the urbanization has caused the rising of temperature and the drop of relative humidity since l945. In particular, the annual mean value of daily minimum temperature has increased at the rate of 2.7℃in the last 50years. The behaviors of land and sea breeze above Fukuoka City have been investigated on the basis of AMeDAS data from 1979 to 1996. Power spectra of wind speed obtained every month show a strong spectral peak at the diurnal frequency. Especially, the value becomes largest in August and September. The onset time of land and sea breeze in each month has been estimated from diurnal variations of mean wind velocity. The onset time of sea breeze at Fukuoka station in May becomes slightly early as years. The difference between the onset times of sea breeze at Fukuoka and Dazaifu stations shows that the penetrating speed ranges from 2m/s to 4m/s