Abstract
In the Kakuda Basin, in the southern part of Miyagi prefecture, frost damages frequently occur in late spring. Air temperatures were measured on a cloudless, calm night in the Kakuda Basin by using a Thermister-Thermometer attached to a bar positioned on an observation vehicle.
Measurements recorded lower temperatures (3-4°C) in the basin than in the coastal area in the early morning. Temperatures were particularly low in the valleys on the western side of the Watari Hills to the east of the basin. This low temperature area gradually expands from midnight to early morning, at which time the low temperature zone appears along the base of the Watari Hills.
Along the Abukuma River, on the other hand, there is a warm zone where there is little change in temperature through the night. This zone seems to be influenced by the comparatively warm water of the river.
Temperature is the lowest at the southwestern foot of the Watari Hills and temperatures in this area were preserved in detail. Temperature changes slowly on calm night, but on windy night, temperatures rise suddenly with increases in wind speed. More frequent and smaller temperature fluctuations occur in the lower area of the valley compared with the upper area.
