Looking for simple correction functions between the mean radiant temperature from the “standard black globe” and the “six-directional” techniques in Taiwan

Mean radiant temperature (T_mrt) values were calculated and compared to each other in Taiwan based on the six-directional and globe techniques. In the case of the six-directional technique (measurements with pyranometers and pyrgeometers), two different T_mrt values were calculated: one representing the radiation load on a standing man [T_mrt(st)] and the other which refers to a spherical reference shape [T_mrt(sp)]. Moreover, T_mrt(T_g) was obtained through the globe thermometer technique applying the standard black globe. Comparing T_mrt values based on the six-directional technique but with different reference shapes revealed that the difference was always in the +/−5 °C domain. Of the cases, 75 % fell into the +/−5 °C Delta Tmrt range when we compared different techniques with similar reference shapes [T_mrt(sp) and T_mrt(T_g)] and only 69 % when we compared the different techniques with different reference shapes [T_mrt(st) and T_mrt(T_g)]. Based on easily accessible factors, simple correction functions were determined to make the T_mrt(T_g) values of already existing outdoor thermal comfort databases comparable with other databases which involve sixdirectional T_mrt. The corrections were conducted directly between the T_mrt(T_g) and T_mrt(sp) values and also indirectly, i.e., by using the values of T_g to reduce the differences between T_mrt(sp) and T_mrt(T_g). Both correction methods resulted in considerable improvement and reduced the differences between the T_mrt(sp) and the T_mrt(T_g) values. However, validations with an independent database from Hungary revealed that it is not suggested to apply the correction functions under totally different background climate conditions.