| Popis: |
The rise in temperature in recent years has significantly affected the entire biosphere, including the beginning and duration of the growing season. The earlier start of the growing season is visible in many crops and trees. Although an increase is generally visible in all temperatures (minimum, maximum, and mean daily), this does not exclude the occurrence of extreme weather conditions that can damage crops. In particular, a special danger is related to frost. farmers need information about changes in the number of days with frost, as well as the last days with frost in spring, not only in the current climate but also in the future. For this reason, changes in the number of days with frost in the period from 1981-2020 were observed in this research. In addition, the last day with frost in spring, the first frost day in autumn, as well as the vegetation season in the observed period were calculated. Since there is no simple method for determining a frost day using only measured values and not observations, a new approach was tested, which defines a frost day as a day in which Tmin < 3 °C and the dew point temperature, calculated with Tmin, < 0 °C. This method was more than 90% successful in forecasting frost. Using this method and regional climate models, the change in the occurrence of frost until the end of the century was examined. A decrease in the number of frosty days in the future is visible, but large changes in the occurrence of the last frosty day of spring are not pronounced. If we take into account the expected earlier onset of vegetation, this can be a big problem in the future. |
