KAI Kenji Univ. of Tsukuba, Inst. of Geoscience, Assist. Prof., 地球科学系, 講師 (50214242)
SUZUKI Rikie Univ. of Tsukuba, Inst. of Geoscience, Res. Assoc., 地球科学系, 助手 (10241788)
|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1992 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1991 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Since the Japan Islands are surrounded by seas, the Land and Sea Breeze (LSB) plays an important role in the local wind system. However previous studies have paid attention to LSBs in some regional areas in Japan, using respective definitions of the LSB and wind data. Therefore, we could not compare the characteristics of the LSB of individual area from the same point of view. In this regard, we attempted to investigate the LSB in the whole Japan using a same method and data, and obtained results that was possible to discuss the regionality of the LSB.
The influence of the Baiu, a rainy season (mainly in June) experienced in the pacific side of north Japan, makes a great contrast of annual change of the LSB frequency between west and east Hokkaido: the maximum frequency appeares in June in west Hokkaido, while the frequency in June is significantly low in east Hokkaido.
The present study focused on the coastal Sea Surface Temperature (SST) that is one of the important geographical factors affected on the LSB. An obvious relationships were found between the LSB and the temperature difference between the SST and air temperature over ground. For example, the alternation of the LSB well corresponds to the time when the temperature difference between the SST and air temperature reverses.
Calm is a meteorological condition having no wind or very weak wind. In this study, the distribution and the annual change of the frequency of the calm condition was statistically investigated over the Kanto Plain. In the result, it was revealed that the maximum frequency (40%) appears in July at 0300JST. At 1500JST, the appearing frequency is low and the frequency is nearly constant throughout the year.
In this study, a field experiment of the boundary layer, that was stably startified during nighttime, was conducted using LIDAR. This experiment demonstrated the relationship between the stability and the concentration of aerosol.