Geographical Distribution and Annual Fluctuation of Thermal Environmental Indices in Japan - Development of a New Thermal Environmental Index for Outdoors and Its Application -

摘要

The objective of this paper is to develop an environmental index describing the effect of outdoor climate on the human thermal sensation, i.e.,' a sensational climate'. To evaluate a sensational climate of the principal cities and towns in JAPAN, a new index has been developed. A new index called 'Predicted Comfortable Clothing' (PCC in clo units) was developed based on the human heat balance equation. This index can evaluate the combined effect of air temperature (Ta), humidity, wind speed, solar radiation and metabolic rate. In the course of development, the corrected humid operative temperature (HOTV, Horikoshi et al. 198?) was further developed to indicate the sensational climate in considering the effect of solar radiation . The temperature-humidity index (THI) was also applied for the evaluation of a sensational climate. These indices were calculated using the weather data observed at 154 cities and towns where the principal observatories are located. Result showed geographical distribution of and the annual fluctuations of outdoor climate of the typical 10 sites out of 154 cities. In summer, Ta in Naha was highest throughout a year as compared with other cities, but PCCs in Matsuyama and Kyoto were -0.5 clo vs -0.25 clo in Naha. In winter, there were significant differences of Ta between Niigata, Shinjo and Karuizawa, but their PCCs were little differences. This indicates that air temperature may be a principal variable but may not evaluate the effect of outdoor climate properly with regard to the human thermal sensation and demonstrates that the newly developed index, PCC may be a powerful tool for evaluating outdoor climate.