AN OVERVIEW OF ANNUAL CLIMATIC CHANGES IN ROMANIA: TRENDS IN AIR TEMPERATURE, PRECIPITATION, SUNSHINE HOURS, CLOUD COVER, RELATIVE HUMIDITY AND WIND SPEED DURING THE 1961-2013 PERIOD

Six meteorological variables from all available Romanian weather stations were tested for trends at annual scale over the 1961-2013 period. Changes in annual air temperature, precipitation, sunshine hours, nebulosity, relative humidity and wind speed were investigated. The Mann-Kendall nonparametric trend test was used in order to find statistically-significant trends, whilst the magnitude of trends was estimated using the Kendall-Theil method. The results point to significant climatic changes at annual scale in Romania. The most drastic change regards the air temperature, which is increasing at all stations. The number of sunshine hours follows a similar pattern, increasing at most stations - except in the mountainous regions of Meridional and Curvature Carpathians. The wind speed presents a significant decreasing signal at the majority of the locations, in agreement with the overall tendency of terrestrial stilling. The annual precipitation amount is rather stable, with increasing trends North-Western Romania and decreasing trends in the Danube Delta (South-East). Cloud cover is generally decreasing, and the relative humidity shows mixed trends. Our findings are in good agreement with previous studies on climatic variability in Romania.