VARIABILITY OF ANNUAL AIR TEMPERATURE IN THE HIGH TATRA MOUNTAINS

Average annual air temperature at meteorological stations covering nearly the whole vertical range of the High Tatra mountains and upper air temperature measurements from close station Poprad were elaborated in period 1961 - 2007 with aim to evaluate long-term variability of air temperature at different altitudes using two different data sources. Upper air temperature data were interpolated to altitudes corresponded to ground stations positions. Homogeneity of time series was checked using the standard-normal homogeneity test. In spite of detected differences between average ground and upper air temperatures, comparison between smoothed homogenized time series showed identical periods of increase or decrease in upper-air and ground data sets. The same coolest and hottest years were detected, similar differences in the annual temperature frequency distributions and increase in the isotherm altitudes were found in period 1991 - 2007 in comparison to the climatic normal 1961 - 1990 in both groups of the data. Vertical temperature gradient was evaluated for selected layers and for the whole investigated vertical profile. The vertical gradient of annual temperature in range of 4.5 - 5.0 degrees C/km was detected for both data groups without significant trends during investigated period in the whole vertical profile. Similar increase in temperature was detected in upper air and ground temperature time series. The linear trends of both, ground and upper-air temperatures, were calculated at all investigated altitudes. Statistically significant linear increase in the annual temperature in range from 0.21 to 0.34 degrees C/decade was detected using the upper-air data. The trends obtained from ground measurements were in the range from 0.21 to 0.30 degrees C/decade (exceptions are the stations Strbske Pleso and Javorina with the insignificant trends of 0.07 and 0.13 degrees C/decade, respectively, but the time series from these stations manifests inhomogeneity).