EFFECTS OF LOCAL URBANIZATION ON THE CLIMATE AND AIR QUALITY IN REGIONAL-SCALE: AN ANALYSIS OF HISTORICAL DATA IN 1975 AND 1985 IN NOBI PLAIN, CENTRAL JAPAN

Abstract

Effects of local urbanization on the regional-scale climate and air quality have been examined by analyzing historical data of meteorology and air quality in 1975 and 1985 in Nobi Plain, which is located on the Pacific Ocean side of central Japan. During the decade, about 12%(-400km²) of total land area in the region was changed from rice paddy field or forest to urban or bare soil area, resulting in an increase in ratio of urban (plus bare soil) area from 40.4% in 1975 to 53.1% in 1985. The analysis was performed for total eighteen days under high pressure system from May through September in both years. The results show that:(1) Daily-high-temperature zone shifted from intense urban-complex in coastal area in 1975 to inland in 1985, while temperatures in the urban-complex did not change significantly in these years. The shift can be attributed to horizontal transport of the heat accumulated in sea breeze layer, which heated up over newly urbanized surfaces in the sea breeze's fetch by artificial sources and increased-sensible-heat-flux.(2) Shift of the zone of high NO₂ concentration also well-correlated with that of the high temperature. These results suggest that urbanization in coastal area affects climate and air quality in inland area (i. e., regional effect of local urbanization), and thus necessity of the planning of land-use to preserve atmospheric environment in regional scale.