Analysis of Determining Factors of Sensible Temperature During Tropical Nights Using S-DoT Big Data in Seoul, Korea

Abstract

This study examines the effect of urban environmental factors on the sensible temperature at night usingSmart Seoul City Data Sensor (S-DoT) to supplement the limitations of previous studies. The automaticweather system (AWS) used in previous studies has the disadvantage that it is difficult to obtain sufficientsamples as there are only 36 in Seoul. Landsat 8 satellite images also have limitations in that they are lessaccurate in estimating atmospheric temperature and challenging to obtain summer data due to many clouds.S-DoT urban big data is highly reliable in indicating the sensible temperature because it can be obtainedthrough 1,100 sensors in Seoul and provides the temperature and humidity measured at the walking level.This study analyzes the linear and nonlinear relationship between sensible temperature and urbanenvironmental factors during tropical nights using interpretable machine learning(IML). The main results ofthis study are as follows: The effect of the road area and altitude on the sensible temperature show significantresults during the night. In the case of the gross floor area(GFA), the effects of residential, commercial, andbusiness facilities on the sensible temperature are different depending on the facility's purpose. The increasein sky view factor(SVF) contributes to reducing the sensible temperature by providing an open space forradiant heat to escape into the sky at night, and the increase in surface roughness(SR) contributes to reducingthe sensible temperature by expanding the range of building shadows cast on the ground. However, this studyfound that the urban thermal environment and the urban factors that determine it have a mostly nonlinearrelationship, and this study suggests a desirable urban design by analyzing the interaction effect of significantvariables. Finally, this study is meaningful in that it empirically analyzed the urban environmental factors atnight based on the sensible temperature, which is an essential indicator of the thermal environment insummer.