Agnieszka WYPYCH, Department of Climatology, Jagiellonian University in Krakow, Poland
Agnieszka SULIKOWSKA, Department of Ecology, Climatology and Air Protection, University of Agriculture in Krakow, Poland
Zbigniew USTRNUL, Department of Climatology, Jagiellonian University in Krakow, Poland
The aim of the study is to evaluate the temporal and spatial variability of spring frosts in Central Europe. To assess the possible impact of air temperature variability on vegetation particular attention has been paid to late spring frost events with respect to the beginning of the thermal growing season. Severe frost events and ground frosts have been also examined as case studies.
Analyses have been conducted for a period: 1951-2020. Gridded data of daily minimum and maximum air temperature data from the E-OBS dataset (version 23.1e) at 0.1° spatial resolution were used, supplemented by daily minimum air temperature data at 5 cm above ground level at particular locations (in-situ data).
Except for a significant shift in the occurrence of last spring frost especially in the western parts of Central Europe which appears earlier up to 5 days per decade (Wypych et. al 2017), the results confirm that the region experiences the occurrence of severe frosts also late in spring. Atmospheric circulation, particularly an extensive high pressure system over eastern Ukraine and Belarus which brings an inflow of cold, continental air masses to Central Europe bears the responsibility (Ustrnul et al. 2014, Wypych et al. 2017). Therefore the key issue is, correspondingly, to examine frequency and trends of circulation patterns influencing spring frosts in Central Europe. Assessing atmospheric circulation changes at regional scale will enable to project future frosts occurrence using a circulation as an explanatory variable. Changes in the frequency of these airflow patterns will result in changes in the risk of frost damage.
Keywords: spring frosts|severe frosts|climate change|atmospheric circulation|Central Europe