Evaluation of thermal continentality within southern Romania and northern Bulgaria (1961-2015)

The assessment of continentality and oceanity of the climate at a global level or within particular regions has lately gained in importance on the background of global warming and its impact on food and water resources. Aiming at understanding these influences, there were analysed the spatial distribution (based on the data from 27 meteorological stations) and temporal variability of four indices (for 19 meteorological stations with complete data series covering the interval 1961–2015). In specialized literature, there are used different continentality and oceanity indices. We studied four of them, but the results indicate that three of these are redundant, as they deliver almost the same information. Consequently, only the results based on Gorczyński Continentality Index (GCI) and Kerner Oceanity Index (KOI) are presented and discussed in greater detail. These indices emphasize the continental character of the climate in the region, except for a narrow strip along the Black Sea Coast, which displays a maritime climate. There did not emerge a clear intensification of continentality (the trends were not statistically significant), in spite of the increase of air temperature in the region during the last two decades. However, a good correlation was obtained between three of the analysed indices (GCI, II and KOI) and North Atlantic Oscillation Index (NAOI).