DOI: 10.17378/AWC2015_51

ABSTRACT. – Temperature inversions in Transylvania. This paper is based on meteorological stations data and statistical methods. Daily maximum and minimum temperatures (from the period 2004-2013) were studied from 22 meteorological stations of Transylvania (s.s.). Factor analysis reveals that temperature inversions are present mainly in winter. Two dominant factors were found, the first is the presence of the depressionar areas, and the second the neighbouring with high relief forms. It is remarkable that Târnăveni (523 m altitude) have approximately the same factor loading for these two factors (that can explain why there are frequently higher minimum temperatures compared to nearest station, Târgu Mureş - 308 m). Additional, daily maximum and minimum temperature from the period 1978-2013 were studied as regard Joseni (750 m) and Bucin (1282 m). Half of the cases, minimum temperature in Joseni is lower than in Bucin. There is no significant trend (at 0.05 levels) regarding yearly number of temperature inversion (taking into account maximum and minimum temperatures). Both in case of maximum and minimum temperature of these two stations, in most cases temperature inversions are related to “anticyclone located east of the Carpathian Basin” and “anticyclone located over the Carpathian Basin” (based on Péczely’s circulation types). To be mentioned that all minimum temperatures under -25 ºC registered at Joseni in that period, were due to temperature inversions. On 3 February 1996, in Bucin minimum temperature was -6.4 ºC, while in Joseni have been recorded −27.6 ºC.

Keywords: temperature inversions, Transylvania, factor analysis, trend.