Local Climates of Yamaguchi Valley (2) : Effect of Ground Surface Conditions on the Air Temperrature Distribution at Night

Local climatological elements such as air temperature, humidity, wind velocity and so on are largely influenced by some physical conditions of ground surface. The difference of air temperature between urban areas and surroundings, especially seen in a local city for a cold season, is also resulted from those different surface conditions. In Yamaguchi Valley (Fig. 1) there is often seen the inversion fog or the cold air lake in winter. To know the degree of development of city temperature, and get in some information on the cooling mechanism of this valley useful for forecasting of local night minimum temperature and frost, the authors tried to observe the distribution of air temperature near the ground and its cooling rate by car equipped with a high sensitive thermister. Results are shown in Figs. 2～5, and Figs. 8, 9. In order to compare these results with the difference of surface conditi ons, a value of 1/cρ√k was introduced from Brunt's formula,....