Changes in urban microclimate are closely related to the nature of the urban substratum and are a key factor in the formation of urban heat islands and an important factor affecting the urban thermal environment. In outdoor space, the human body is close to the ground, and ground radiation significantly affects mean radiation temperature. However, the effect of ground radiation may vary due to differences in environment and materials. To investigate the thermal comfort of different underlayment surfaces under outdoor thermal radiation, this study conducted subjective questionnaire research and field measurements of objective parameters on the radiation characteristics of four other underlayment surfaces and their personnel thermal comfort. It came to the following three conclusions: 1) In sunny weather, with the increase of thermal perception and solar radiation, the radiation gradually exceeds the temperature as the main factor affecting personnel thermal perception; 2) MRT is the main factor for the difference in personnel thermal perception at the same temperature. For different albedo underlayment materials, the change in personnel thermal perception is not the same for every 1 °C change in MRT; 3) The neutral physiological equivalent temperature of different underlayment surfaces ranked as asphalt > grass > concrete > limestone, which was the opposite order of reflectivity of underlayment surface. Materials with higher reflectivity and lower solar radiation absorption rates should be considered when selecting outdoor underlayment surfaces.

中文翻译：

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城市不同下垫面室外热舒适度研究

城市小气候的变化与城市底层性质密切相关，是城市热岛形成的关键因素，也是影响城市热环境的重要因素。在室外空间，人体靠近地面，地面辐射对平均辐射温度影响显着。然而，地面辐射的效果可能会因环境和材料的差异而有所不同。为了探讨室外热辐射下不同垫层表面的热舒适性，本研究对另外四种垫层表面的辐射特性及其人员热舒适性进行了主观问卷研究和客观参数的现场测量。得出以下三个结论：1）晴天时，随着热感知和太阳辐射的增加，辐射逐渐超过温度成为影响人员热感知的主要因素； 2）MRT是同一温度下人员热感知差异的主要因素。对于不同反照率衬垫材料，MRT每变化1℃，人员热感知的变化并不相同； 3)不同垫层表面的中性生理等效温度顺序为沥青>草地>混凝土>石灰石,与垫层表面反射率的顺序相反。选择室外垫层表面时应考虑反射率较高、太阳辐射吸收率较低的材料。