1984 Volume 62 Issue 6 Pages 864-879
The sea and land breezes in the northern region of Kyushu Island in Japan under the condition of no synoptic wind in typical summer season are simulated by a three dimensional numerical model.
This study provides an evaluation of the diversification of the local circulation owing to the topography, e. g. irregular seashore lines and mountainous topographies. In order to investigate the influence of mountainous topography on the local circulation in Kyushu, we compared the case of the realistic ground elevation with that of the flat in the northwestern region of Kyushu which is characterized by the irregular coastal lines, the comparative flat topography and dispersive mountains. Further we also compared them with the case of the realistic topography in the north-eastern region of Kyushu which has the monotonus seashores and the spread mountain areas.
In the northern region of Kyushu, the irregular coastal lines (esp. topography of peninsula) produce characteristic local circulations and variation of winds in connection with mountainous topographies.
The mountainous topographical effects are summarized; (1) the upward vertical winds concentrate above the mountain area in the day time (down slope wind in the night), (2) the horizontal winds are oriented by the valley (e. g. in the sea area surrounded by a mountainous topography) and (3) the winds are enforced in the area of converged mountainous topography.
The sea breezes in the small islands near the Kyushu are strongly affected by that in Kyushu. Further the penetration of sea breeze to inland or other area is effective factor on the diurnal wind variation at any place (esp, in the western region).