title: Validation of the mean radiant temperature simulated by the RayMan software in urban environments.
abstract: The RayMan software is worldwide applied in investigations on different issues in human-biometeorology. However, only the simulated mean radiant temperature (Tmrt) has been validated so far in a few case studies. They are based on Tmrtvalues, which were experimentally determined in urban environments by use of a globe thermometer or applying the six-directional method. This study analyses previous Tmrtvalidations in a comparative manner. Their results are extended by a recent validation of Tmrtin an urban micro-environment in Freiburg (southwest Germany), which can be regarded as relatively heterogeneous due to different shading intensities by tree crowns. In addition, a validation of the physiologically equivalent temperature (PET) simulated by RayMan is conducted for the first time. The validations are based on experimentally determined Tmrtand PET values, which were calculated from measured meteorological variables in the daytime of a clear-sky summer day. In total, the validation results show that RayMan is capable of simulating Tmrtsatisfactorily under relatively homogeneous site conditions. However, the inaccuracy of simulated Tmrtis increasing with lower sun elevation and growing heterogeneity of the simulation site. As Tmrtrepresents the meteorological variable that mostly governs PET in the daytime of clear-sky summer days, the accuracy of simulated Tmrtis mainly responsible for the accuracy of simulated PET. The Tmrtvalidations result in some recommendations, which concern an update of physical principles applied in the RayMan software to simulate the short- and long-wave radiant flux densities, especially from vertical building walls and tree crowns.
authors.affiliation: Chair of Environmental Meteorology, Albert-Ludwigs-University of Freiburg, Werthmannstrasse 10, 79085, Freiburg, Germany. catharina96@gmail.com.
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Lee
authors.affiliation: Chair of Environmental Meteorology, Albert-Ludwigs-University of Freiburg, Werthmannstrasse 10, 79085, Freiburg, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: Mayer
mesh_terms: D002947:Cities; D003198:Computer Simulation; D006801:Humans; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012984:Software; D013472:Sunlight; D013696:Temperature; D013697:Thermosensing
keywords: PET; RayMan software package; T mrt; Urban environment; Validations