Temporal Analysis of Urban-Suburban PET, mPET and UTCI Indices in Belgrade (Serbia)

Milica Pecelj,Mirjam Vujadinović,Dijana Đurić,Milena Cvetkovic,Andreas Matzarakis,Milan Radovanović,Nemanja Vagić

doi:10.3390/atmos12070916

Abstract

The analysis of the bioclimatic conditions is becoming increasingly relevant in climate interpretations for human needs, particularly in spatial planning, tourism, public health, sports events, bio-prognosis, etc. In this context, our study presents general temporal bioclimatic conditions in Belgrade, defined based on the PET, mPET and UTCI heat budget indices. Monthly, seasonal and annual indices were analyzed for urban and suburban weather stations based on 43 annual sets of meteorological data obtained by hourly observations at 7 h and 14 h CET. This study aims to present the distribution of PET, mPET and UTCI indices to show the pattern of each index in a mild climate location and to examine annual and seasonal differences of each index in the Belgrade urban center and suburban part of the city. The study results indicate higher biothermal stress in the urban area compared to the suburban zone and that the indices are congruent during the summer. At the same time, during the winter, they are more difficult to compare due to their peculiarities becoming more noticeable. The results obtained of all mean monthly and mean annual values of all three indices clearly indicate the difference that follows the definition of the urban heat island (UHI), particularly those from morning observation and winter season. The UTCI index shows the most significant monthly, seasonal and annual difference between urban and suburban areas for both observations. The annual difference of ΔUTCI7h amounts to 1.5 °C is the same as the annual difference of minimum temperatures (Δtmin). In contrast, the annual differences of ΔPET7h ΔmPET7h are °smaller (0.8 °C and 0.7 °C) and closer to the annual differences of maximum temperatures Δtmax amounted of 0.6 °C.

Highlights

A large portion of the world’s population lives in tightly built and densely populated urban areas
Based on the proposed methodology and the multiyear meteorological data, biothermal conditions were presented in three separate sections: (i) Frequencies of physiologically equivalent temperature (PET), modified physiologically equivalent temperature (mPET) and Universal Thermal Climate Index (UTCI) thermal stress classes per each month, with a comparison between Belgrade and Surcin area, (ii) average monthly and annual PET, mPET and UTCI and (iii) differences in indices between Belgrade and Surcin areas
Results obtained for Belgrade urban and Surcin suburban area of all mean monthly and mean annual values of all three indices clearly indicate the difference, which follows the definition of the urban heat island (UHI)

Summary

Introduction

A large portion of the world’s population lives in tightly built and densely populated urban areas. Studies of the Belgrade climate conducted to date have mostly been based on individual meteorological parameters used for the analysis of the urban climate characteristics. These mainly referred to the characteristics of urban heat islands defined by average air temperatures or extreme air temperatures [1,2,3,4,5,6,7], air humidity characteristics in urban and suburban areas [8] and heatwave analysis [9,10,11,12,13,14,15,16,17,18,19]. Regarding the assessment of bioclimatic indices, simple index Steadman apparent temperature [20]

Objectives

Methods

Results

Discussion

Conclusion