Offering a Model for Estimating Black Globe Temperature According to Meteorological Measurements Publisher



Hajizadeh R¹ ; Farhang Dehghan S² ; Golbabaei F³ ; Jafari SM⁴ ; Karajizadeh M⁵ Show Affiliations
Source: Meteorological Applications Published:2017

Abstract

Black globe temperature (Tg) is one of the most common measurement variables used for assessing heat stress; however, it is usually not reported in meteorological data. This study developed a model to estimate Tg based on meteorological measurements, in order to calculate the occupational heat stress index in outdoor workplaces. This descriptive and analytical study was conducted from May to September 2013 in Qom, Iran. Environmental variables such as natural wet-bulb temperature (Tnw), dry-bulb temperature (Ta), solar radiation (SR) and relative humidity (RH) were measured by meteorological instruments in weather stations and Tg was measured by a globe thermometer in the same situations at different times. Data were analysed using IBM SPSS16. Independent variables including Tnw, Ta, SR and RH and the dependent variable Tg were introduced to the software, and several regression models were obtained. Finally, a model that had the most appropriate correlation with a significance level of 0.05 was chosen as the best model. The correlation co-efficients between Tg and Tnw, Ta, SR and RH were obtained as 0.84, 0.63, 0.75 and −0.75, respectively. The results showed that Ta, SR and RH can justify about 90% of the variation in Tg. There was a significant relationship between Tg and Ta, SR and RH (p < 0.05). The correlation co-efficient between actual and estimated data was 0.95 (p < 0.001). The model obtained can be trusted to estimate the black globe temperature in a hot and dry environment and can be useful in assessing occupational heat stress in outdoor workplaces. © 2017 Royal Meteorological Society