engleski

Temperature sums and climatic variations in the Parg region

The growth of plants is correlated more or less closely with the accumulated air temperature above specific temperature threshold. By knowing the mean temperature sums (sum of the differences between mean daily temperature and temperature threshold) during the vegetation period it is possible to give an estimate of the temperature conditions in a region and to plan the growing of plant species. Thus, the temperature sums above thresholds 0C, 5C, 10C, 15C and 20C and their linear trends have been analyzed at the mountain Parg stations for the vegetation period from 1951 to 2004. As the growth of plant depends on the other climatic parameters too, linear trends of air temperature, pressure, relative humidity, precipitation, snow cover, cloudiness, insolation duration and atmospheric phenomena have been also presented. The results of linear trend analysis and the Mann-Kendall test indicate that the existence of a significant linear trend temperature sums above thresholds 15C and 20C (increasing by time) are the consequence of significant increase in mean maximum temperature in spring and summer. The increase of absolute maximum temperature is the greatest during the winter time and the smallest during the spring, while in autumn they show a negative trend. Significant increases of the mean seasonal temperature and absolute minimum temperature have been established only in spring. The annual values of mean air pressure, number of warm days and days with dew also show significant positive trend. The greatest climatic variations were observed in winter. While the mean air pressure, mean and absolute maximum temperature and insolation duration are increasing, the number of days with fog, rime and snow grain is decreasing. We believe that the main reason for this is increasing frequency of anticyclonic situations. A tendency towards a decrease in the annual and seasonal values of precipitation amount and increase in mean air temperature and insolation duration (not only in summer but also in winter) could have a negative influence on the mountain flora.

temperature sums ; climatic variations ; the mountain Parg station

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