The 850 hPa air pressure level is situated about 1.5 km above sea level. This means that the surface does not influence the temperature at this altitude, so the diurnal temperature variations are small. They are about 2-3 degrees, or they do not exist, at all. This is why temperature of the 850 hPa level is used for identification of air masses and location of warm and cold fronts. Moreover, temperature variation of the 850 hPa level can be analysed in themselves, as indicators of climate 1500 meters above the sea level. The 1973-2014 period, analysed in this study, was chosen as the longest available series in Cluj-Napoca. The results, concerning the evolution of temperature at this standard isobaric level pointed at strong warming in the last 10-15 years. In the last 7 years the highest temperatures were higher by one degree at the 850 hPa lever than in the preceding years. The heating at the analyzed isobaric level overlaps the growing of ground temperature, analyzed the medium annual temperature in the period 1973-2014.
Full Text Finder