Changes in Air Temperature and Snow Cover in Winter in Poland (original) (raw)
Related papers
Changes of snow cover in Poland
Acta Geophysica
The present paper examines variability of characteristics of snow cover (snow cover depth, number of days with snow cover and dates of beginning and end of snow cover) in Poland. The study makes use of a set of 43 long time series of observation records from the stations in Poland, from 1952 to 2013. To describe temporal changes in snow cover characteristics, the intervals of 1952-1990 and of 1991-2013 are compared and trends in analysed data are sought (e.g., using the Mann-Kendall test). Observed behaviour of time series of snow-related variables is complex and not easy to interpret, for instance because of the location of the research area in the zone of transitional moderate climate, where strong variability of climate events is one of the main attributes. A statistical link between the North Atlantic Oscillation (NAO) index and the snow cover depth, as well as the number of snow cover days is found.
Change of maximum snow cover depth in Poland – trends and projections
Időjárás
⎯ The present paper examines the observed variability of maximum depth of snow cover in Poland and its projections for near (2021-2050) and far (2071-2100) future. The study makes use of a set of 43 time series of observation records from stations in Poland, from 1951 to 2013. For the future, two downscaling experiments were conducted with the aim of producing reliable high-resolution climate projections of precipitation and temperature for Poland. The results of these projections were used as the input data to the seNorge snow model in order to transform bias-adjusted daily temperature and precipitation into daily snow conditions. Observed behavior of time series of snow is complex and not easy to interpret. The changes (if any) are dominated by strong inter-winter and intra-winter variability, rendering trend detection difficult. Projected seasonal snow cover depth (for winter as well as spring and autumn) as simulated by the snow model for the near and far future show decreases. The rate of decreasing maximum snow depth is expected to at least double by 2071-2100.
Changes in the Occurrence of Late Spring Frost in Poland
Agronomy
Trends in the appearance of the last spring frost for three thresholds of minimum daily air temperature at the height of 2 m and near the ground were examined for six meteorological stations located in two agricultural regions in Poland. For most time series, the last spring frost, calculated as a consecutive day of the year, showed a statistically significant trend indicating its earlier appearance from 1.6 to about 3.5 days per decade. The date of the last spring frost was also calculated in relation to the ongoing growing season. In this case, few statistically significant changes in the dates of the last frosts were found. The probability of the last spring frost on a specific day of the calendar year and the day of the growing season was also examined for two periods: 1961–1990 and 1991–2020. For low probability levels corresponding to the early dates of the last spring frost, the last frost usually occurred much earlier (6–14 days) in 1991–2020. With the probability levels of ...
Journal of Ecological Engineering, 2021
Frosts are the most common natural phenomena during the transitional seasons. A frost occurs when the average daily air temperature is positive and the minimum temperature drops below 0°C. The problem of frost occurrence (especially spring frosts) is very important from the point of view of the threats related to crop plant cultivation, because it causes losses in crops when taking place during the plant growth. The aim of the study was to analyze the occurrence of air frosts in the years 2001–2018 in the region of central-eastern Poland on the basis of meteorological data. In the region of central-eastern Poland, the greatest number of days with mild, moderate and strong frosts in 2001–2018 was observed in Białowieża; conversely, it was the lowest in Warsaw. The distribution of the number of days with frosts in spring was similar. The distribution of autumn frosts, however, was different. The greatest number of days with autumn frosts was observed in Terespol and Białowieża, the le...
The thermal seasons variability in Poland, 1951–2010
Theoretical and Applied Climatology, 2015
The aim of this study is to detect variability and changes in the occurrence of the thermal seasons in Poland during the period from 1951 to 2010. A monthly temperature dataset using average area values allowed the researchers to set proper occurrence dates for the thermal seasons' beginnings and length according to the following criteria: winter (t < 0°C), early spring (0-5°C), spring (5-15°C), summer (t > 15°C), autumn (5-15°C) and early winter (0-5°C). Statistically significant long-term trends have been detected for the occurrence dates of the thermal seasons' beginnings and season length. Seasonal variability accelerated significantly since the end of the twentieth century. The trend of limiting wintertime in Poland is 0.64 days per year, while summer and early spring seasons are longer by approximately 0.30 and 0.25 days per year, respectively. All seasons since thermal early spring until thermal summer tend to occur earlier, while the following seasons have the opposite trend. As a result, the number of years without thermal winter has substantially increased in the past 20 years. Simultaneously, thermal summer became the longest season in 85 % of years after 1990 in comparison to less than 50 % in the period from 1951 to 1970. Also, the change in the annual course of monthly mean temperature results in the fact that thermal spring is becoming longer than thermal autumn.
Snow cover in western Poland and macro-scale circulation conditions
International Journal of Climatology, 2002
The aim of the study was to find out the connection between the nature of winters in the western part of Poland (excluding the Sudety mountains) and the fluctuation in the atmospheric circulation in the North Atlantic region determined by the North Atlantic Oscillation (NAO) index. An attempt was made to establish the correlation between the NAO index and specific meteorological parameters in Poznań. The strongest positive correlation was obtained for the mean winter temperature (December-March) and strong negative correlation was found for the number of days with snow cover. Winter precipitation in Poznań was least associated with the NAO. The correlation coefficient was small and not significant. In the next stage of the study, the area of western Poland was examined; however, only one parameter, i.e. the number of days with snow cover, was taken into consideration. At each of 29 stations distributed in the study area the number of days with snow cover was proved to be strongly negatively correlated with the NAO index. Finally, the frequency of air flow directions was taken into consideration and their association with the NAO was examined. A strong negative correlation was obtained for the frequency of northeasterly and easterly air flow directions and a strong positive correlation was calculated for the frequency of westerly and northwesterly airflow directions. Such findings are consistent with the westerly flow of air masses during the positive phase and with the northerly and easterly flows during the negative phase. The results lead to the conclusion that the positive phase of the NAO causes mild and less snowy winters, whereas the negative phase increases the probability of severe and snowy winters in western Poland.
Changes in thermal and precipitation conditions in Poland in 1971–2010
Annals of Warsaw University of Life Sciences, Land Reclamation, 2014
Changes in thermal and precipitation conditions in Poland in 1971-2010. The article presents changes in thermal and precipitation conditions on Polish territory in the years 1971- -2010 based on data from six meteorological stations (Koszalin, Olsztyn, Poznań, Lublin, Opole and Kraków). These data concern the monthly average air temperature, precipitation and the number of days with precipitation per month. Based on the analysis of changing trends in the study of meteorological elements, authors observed an increase in the mean annual air temperature of about 0.9°C over 10 years in all localities. In contrast, trends in the average monthly air temperatures were characterised by temporal and spatial variation. As a result of the increase in temperature, there was a change in the dates signifying the beginning and the end of the thermal periods: farming (OG), vegetation (OW), intensive vegetation (OIW) and maturation or thermal summers (OD/L). A tendency for these periods to start ear...
Snow cover in eastern Europe in relation to temperature, precipitation and circulation
International Journal of Climatology, 2004
The basic characteristics of snow cover occurrence in eastern Europe are described. For each month from October to May the range of 'active' snow-cover areas in Europe was determined. The boundary criterion for 'active' regions was adopted as snow-cover probability of between 10 and 90%. The correlation coefficients between the snow-cover characteristics (number of days with snow cover and its monthly mean depth) and other climatic variables (temperature and precipitation) were calculated. A strong positive correlation between the annual number of days with snow cover and the annual number of days with mean temperature <0°C was discovered for most parts of the study area. A negative correlation between the monthly number of days with snow cover and monthly mean temperature was found and its spatial distribution was analysed. A positive correlation between snow depth and precipitation appeared significant only in some areas. The influence of atmospheric circulation, expressed by North Atlantic oscillation (NAO) index values, on snow cover in the particular months was analysed. The correlation between the number of days with snow cover and the NAO index is large and statistically significant only in central Europe and it becomes insignificant to the east of 30°λ E. High values are noted only in the winter months. In autumn and spring, when the range of the 'active' areas moves to the east and the NAO becomes weak, the correlation is very small.