การประเมินความเข้มของเกาะความร้อนในเมืองเชียงใหม่

Abstract

This research aims to evaluate on Urban Heat Island Intensity in Chiang Mai city, to study the temperature distribution along surveyed routes and to study the relation between population density, building density and traffic density on UHII. The ambient air temperature was measured by thermocouples at a constant altitude of 2 m above the road by mobile surveying approach. The surveyed routes were divided to urban routes and rural routes. The Urban Heat Island Intensity (UHII) was calculated from an average ambient air temperature difference between urban and rural areas. Experimental investigations were carried out in 2 seasons consist of summer (March-May 2013) and winter (November 2013-February 2014). Experimental investigations were carried out in 2 periods which were a day time (12.30-02.30 pm) and a night time (10.00 pm-00.00 am) on Monday, Wednesday, and Sunday. The results show that the UHII in Chiang Mai city is positive all day and night through summer and winter as follows. The UHII of summer’s day, summer’s night, winter’s day and winter’s night are 1.07 °C, 1.27 °C, 0.58 °C, and 1.34 °C, respectively. This means that temperature in Chiang Mai City is higher than rural area. The temperature distribution depend on characteristic in each places, the temperature is high in area with high traffic and building density while the temperature is low in natural area. The relation between population density, building density and traffic density on UHII, in the result show that the 3 factors have direct effect on UHII. And the difference of UHII in each time is resulted from population, building and traffic density. As below the UHII in summer’s day is higher than winter’s day because in summer’s day, influence of traffic density is 87.50% while in winter’s day is 72.72%. For UHII in summer’s night is lower than winter’s night because influence of traffic density increase from 28.57% in summer’s night to 63.33% in winter’s night. While UHII in summer’s day is lower than summer’s night because influence of building density increase from 9.38% in summer’s day to 50.00% in summer’s night and influence of population density increase from 3.12% in summer’s day to 21.43% in summer’s night. The last UHII in winter’s day is lower than winter’s night because influence of building density increase from 18.18% in winter’s day to 26.67% in winter’s night since heat is released from building in this time.