Comparative Study On Residents’ Outdoor Thermal Comfort In Urban Parks In China’s Cold Regions

The welfares led by a comfortable thermal environment include the increment of attraction of outdoor space in urban parks,improvement of the public health of people,alleviation of the urban heat island effect.Outdoor thermal comfort is an important criterion for evaluating the thermal environment,but due to the limitation of a standard methodology for outdoor thermal comfort research,it is difficult to compare thermal benchmarks between different climate zones and research areas.Therefore,this study selected Beijing,Xi’an,and Hami as typical representative cities in China’s cold climate regions to conduct outdoor thermal comfort research.The study used a unified standard weather measurement and questionnaire survey method to conduct outdoor thermal comfort surveys in 10 open spaces in three parks.The study selected Universal Thermal Climate Index（UTCI）as the evaluation index of outdoor thermal comfort,then compared the differences in the thermal benchmarks of the residents in the three regions.Finally,through the multiple linear regression analysis of the residents’thermal votes and micro-meteorological elements,the outdoor thermal comfort evaluation index was calibrated,and the prediction thermal voting model（Beijing Outdoor Comfort Index,BOCI;Xi’an Outdoor Comfort Index,XOCI;Hami Outdoor Comfort Index;HOCI）of the three regions were established.Results demonstrated that:（1）In winter,residents’average clothing thermal resistance:clo _Xi’an（1.63）>clo _Beijing（1.50）>clo _Hami（1.43）.Overall,the average thermal resistance of women’s clothes in the three regions was higher than that of men,indicating gender.The difference had a particular impact on human thermal comfort and thermal adaptation behavior;（2）Air temperature and globe temperature were two primary factors affecting residents’thermal sensation in the three cities during winter.Residents’thermal sensation in Beijing has a strong negative correlation with wind speed.（3）Xi’an residents had the highest neutral UTCI（17.3℃）,followed by Beijing（17.0℃）and Hami（6.4℃）.Xi’an residents had slightly wider neutral UTCI range（NUTCIR）（7.9-26.7℃）compared to Beijing（8.7-25.4℃）,while Hami residents had the narrowest NUTCIR（1.5-11.3℃）.（4）Based on the 80%thermal acceptable range difference,UTCI has been corrected,the“no thermal stress”range in the three cities was 6.1-26.0℃in Beijing,6.7-25.5℃in Xi’an,and-2.2-12.2℃in Hami;（5）Based on the 7-level scale of ASHRAE,this study used multiple linear regression to calibrated outdoor thermal comfort index models for three regions:BOCI（Beijing Outdoor Comfort Index）,HOCI（Hami Outdoor Comfort Index）and XOCI（Xi’an Outdoor Comfort Index）to predict local residents as the vote value for judging the thermal environment quality.This study conducted a comparative study of thermal comfort in typical representative cities in cold climate regions and established an outdoor predictive thermal voting models.The research results can provide quantitative guidance for landscape design based on outdoor thermal comfort evaluation,and provide quantitative indicators for the formulation of landscape design standards for improving outdoor thermal comfort.