Hrvatske vode
 
Usporedba srednje vrijednosti temperature zraka (na različitim vremenskim skalama) izračunata pomoću dvije različite metode
A comparison of the mean value of air temperature (on different time scales) calculated by two different methods

Ognjen Bonacci1, Tanja Roje-Bonacci1, Ivana Željković2

Sažetak/Abstract: 

Izraz za definiranje točne srednje dnevne temperature zraka, T0, glasi: T0=(sum(Ti)/24). U klimatološkoj praksi Hrvatske, ali i brojnih srednjoeuropskih država za računanje srednje dnevne temperature zraka, T1, koristi se sljedeći izraz koji se nastavno naziva službenim: T1=(T7+T14+2*T21)/4. Ova dva izraza daju različite vrijednosti srednjih dnevnih, a potom i mjesečnih te godišnjih temperatura zraka. U članku je izvršena usporedba srednjih dnevnih, mjesečnih i godišnjih temperatura zraka mjerenih na meteorološkim postajama Zagreb-Grič i Dubrovnik izračunatih korištenjem oba izraza za razdoblje od 1. siječnja 1999. do 31. prosinca 2014. Analizirane su razlike između raspona točnih i službenih vrijednost srednjih dnevnih temperatura zraka Zagreb-Griča i Dubrovnika. Ujedno su proračunate te analizirane razlike između točnih srednjih dnevnih, mjesečnih i godišnjih vrijednosti temperatura zraka, T0, izmjerenih na meteorološkim postajama Dubrovnik i Zagreb-Grič. Utvrđeno je da su točne srednje mjesečne i godišnje temperature zraka, T0, na meteorološkoj postaji Dubrovnik uvijek više od onih izračunatih službenim izrazom (2), dok su na meteorološkoj postaji Zagreb-Grič one uvijek niže. S produžavanjem vremenske skale obrade smanjuju su vrijednosti razlike, ali su one još uvijek nezanemarive. Članak je pisan s namjerom da se izučavanju ove problematike u bliskoj budućnosti posveti veću pažnju.

 

The formula used for the determination of accurate mean daily air temperature, T0, is: T0=(sum(Ti)/24). In the climatological practice in Croatia as well as numerous Central European countries, mean daily air temperature, T1, is calculated by using the following formula (called “official” further in the text): T1=(T7+T14+2*T21)/4. These two formulas result in different values of mean daily, monthly and annual air temperatures. In the paper we have compared mean daily, monthly and annual air temperatures measured at the meteorological stations Zagreb-Grič and Dubrovnik in the period from 1 January 1999 to 31 December 2014 and calculated by applying both formulas. The differences between the ranges of the accurate and official values of mean daily air temperatures at Zagreb-Grič and Dubrovnik stations were analyzed. Additionally, the differences between the accurate mean daily, monthly and annual values of air temperatures, T0, measured at the meteorological stations Dubrovnik and Zagreb-Grič were also calculated and analyzed. It was determined that the accurate mean monthly and annual air temperatures, T0, at the meteorological station Dubrovnik were always higher than those calculated by using the “official” formula (2), whereas at the meteorological station Zagreb-Grič they were always lower. When the temporal scale is extended, the values of these differences are smaller, although still not negligible. The paper was written with the aim of attracting attention to the necessity of studying these issues in the near future.

Kategorija: 
Stručni članak / Professional Paper
Ključne riječi/Key words: 

srednja dnevna, mjesečna i godišnja temperatura zraka, razlika točnih i službenih temperatura zraka, Zagreb-Grič, Dubrovnik

mean daily, monthly and annual air temperature, difference between accurate and official air temperatures, Zagreb-Grič, Dubrovnik

Podaci o autorima/Authors affiliations: 

1Fakultet građevinarstva, arhitekture i geodezije Sveučilišta u Splitu, Matice hrvatske 15, Split, obonacci@gradst.hr

 

2nezavinski istraživač (independent researcher)

Literatura/References: 

Bonacci, O.; Željković, I.; Šakić-Trogrlić, R.; Milković, J. (2013.a): Differences between true mean daily, monthly, annual air temperatures and air temperatures calculated with three equations: a case study from three Croatian stations. Theoretical and Applied Climatology, 114:271-279.

 

Bonacci, O.; Željković, I.; Šakić-Trogrlić, R.; Milković, J. (2013.b): Prilog raspravi o računanju srednjih temperatura zraka. Hrvatske vode, 21(84):129-136.

 

Bonacci, O.; Željković, I. (2016.): Differences between true mean temperatures and means calculated with four different approaches: a case study from three Croatian stations. Theoretical and Applied Climatology, DOI:10.1007/s00704-016-1993-5.

 

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