Tropospheric thermal field variability over Poland in the context of climate change

Abstract

Based on the results of radiosounding measurements from all Polish aerological stations, an analysis of temperature changes in the troposphere and tropopause over Poland was carried out. The study was performed for data from 1981 to 2018 at 00 UTC for five main isobaric surfaces (MISs): 850, 700, 500, 300 and 200 hPa and for the tropopause. It was found that the tropospheric temperature variability is highest in the cold months of the year and lowest in summer. Annual temperature variability in the upper troposphere is less than in the lower. Temperature trends for the MISs from 850 to 300 hPa for the year and summer are positive and almost everywhere statistically significant at a significance level of .05. For a year, they average from about 0.2°C to 0.5°C/decade. In summer, they are slightly greater and are 0.4–0.5°C. On the MIS of 200 hPa over Poland, however, there are negative thermal trends, both in the year and in summer. They are approximately −0.1°C/decade. In winter, the trends are much smaller than in the summer or for the year. In the lower troposphere they are weak and positive, while in the upper troposphere they are weak and negative. Negative tendencies in the thermal tropopause over Poland were found. For the year and seasons, this trend ranges from −0.2 to −0.3°C/decade. The obtained results regarding the temperature of the troposphere and tropopause over Poland correspond with the results of earlier studies from Europe and the around world. They confirm the warming of the lower and cooling of the upper troposphere with the tropopause, which has been taking place in the last few decades.

Reasons for shortening snow cover duration in the Western Sudetes in light of global climate change

“…The observed increase in air temperature in the lower and middle troposphere over Poland (Urban et al, 2021) confirmed by measurements from ground stations in the Western Sudetes (Migała et al, 2016) with a simultaneous increase in sunshine duration (Urban, Migała, & Pawliczek, 2018) and changes in the frequency of circulation types with warm marine air masses affect various indicators of SC and its occurrence. An analysis of the mean dates of the start and end of SC in the Western Sudetes shows that it appears earliest in the highest parts of the mountains (early October) and progresses down the slopes (mid‐November) and disappears earliest in the lower parts of the slopes (early April) and progresses up the slopes and toward the tops of the mountains (late May).…”