Abstract
In order to clarify the urbanization intensity of Daegu Metropolitan and its characteristics, comparative study on the variation of the cooling rate of two different sites was carried out using observation data for 40 years by Korea Meteorological Adminstration. Daegu Metropolitan and Chupungnyung represent well urbanized and rural areas, respectively. In comparison with Chupungnyung, yearly mean temperature at Daegu Metropolitan increases rapidly and especially the differences of minimum temperature increasing rate during 40 years becomes greater. These differences of regional warming are caused by the different urbanization intensity between two sites. And the impact of anthropogenic heat due to urbanization should be stronger in nighttime than in daytime. Sensible heat advection by regional wind during 6 hours from 18 LST contributes to atmospheric cooling. For this reason wind speed is in proportion to cooling rate of atmosphere. However, wind after 24 LST induces the warm air advection and makes decrease the cooling rate in urban area. Although the cooling rates between Daegu Metropolitan and Chupungnyung are some different, the variation tendencies of cooling rate of two site are almost same. Therefore atmospheric cooling rate in nighttime tends to be associated with the intensity of wind speed.