RayMan and Thermal Bioclimate – History, Development and Applications

The RayMan model (www.urbanclimate.net/rayman) was created to evaluate short wave (SW) and long wave (LW) radiation fluxes which carry significant impacts upon the humans. The model provides a means to evaluate building structures of diverse complexities which allows it to analyse the effect of numerous planning and design scenarios at multiple scales. The model calculates mean radiant temperature (Tmrt) a variable that is crucial within the human energy balance model, thus permitting the evaluation of microclimatic factors upon the human biometeorological system. In correlation with the previously mentioned thermal indices, the PMV, PET, SET*, UTCI, PT, and mPET, can be calculated within the RayMan model. Furthermore, specificities pertaining to urban typo-morphological characteristics and amenities can be created and/or imported within its embedded obstacle plug-in. Such an input task, if required, can moreover be aided through the superimposition over a respective raster file to specify the position of such elements, as well as the importation of shape and/or text files to introduce obstacles and/or topographical characteristics. 

Consequently, and based upon these described input possibilities, sunshine duration (accounting, or not, for the ratio of sky restriction, via the Sky View Factor (SVF)), assessment of diurnal and/or nocturnal mean, max or total of G for present and future urban settings can be examined. In association with the estimation of thermal indices within complex environments, the user can introduce meteorological data manually, or do so via the importing of different data files (based upon divergent periodicities, resolutions, and time-frames), which must be selected appropriately based upon the intended nature of the desired study and/or statistical assessments.

Several applications such as micro scale modifications in urban areas, setting up thresholds for heat health warnings and for extreme events (i.e. FIFA 2022 and Olympic Games in Tokyo) have been helpful for decision making and communication.