Joanna Wibig - Academia.edu (original) (raw)

Papers by Joanna Wibig

Meteorology Hydrology and Water Management

Interpolation of precipitation data is a common practice for generating continuous, spatially-dis... more Interpolation of precipitation data is a common practice for generating continuous, spatially-distributed fields that can be used for a range of applications, including climate modeling, water resource management, and agricultural planning. To obtain the reference field, daily observation data from the measurement network of the Institute of Meteorology and Water Management-National Research Institute was used. In this study, we compared and combined six different interpolation methods for daily precipitation in Poland, including bilinear and bicubic interpolation, inverse distance weighting, distance-weighted average, nearest neighbor remapping, and thin plate spline regression. Implementations of these methods available in the R programming language (e.g., from packages akima, gstat, fields) and the Climate Data Operators (CDO) were applied. The performance of each method was evaluated using multiple metrics, including the Pearson correlation coefficient (RO) and the correspondence ratio (CR), but there was no clear optimal method. As an interpolated resulting field, a field consisting of the best interpolations for individual days was proposed. The assessment of daily fields was based on the CR and RO parameters. Our results showed that the combined approach outperformed individual methods with higher accuracy and reliability and allowed for generating more accurate and reliable precipitation fields. On a group of selected stations (data quality and no missing data), the precipitation result fields were compared with the fields obtained in other projects-CPLFD-GDPT5 (Berezowski et al. 2016) and G2DC-PLC (Piniewski et al. 2021). The variance inflation factor (VIF) was bigger for the resulting fields (~5), while for the compared fields, it was below 3. However, for the mean absolute error (MAE), the relationship was reversed-the MAE was approximately half as low for the fields obtained in this work.

Heat waves and droughts are two the most frequent weather extremes in Poland, both excerbated by ... more Heat waves and droughts are two the most frequent weather extremes in Poland, both excerbated by the ongoing global warming. Very often they occur simulateously. The aim of this presentation is identification of cases of simultaneous occurence of these extreme situations, examination of their spatial extent, frequency of occurrence and long-term variability. Reasons of their occurrence are also analysed. On the basis of data from the period 1966-2020 from about 40 stations in Poland reference evaporation indices will be estimated based on Palmer-Monteith formula and together with precipitation records used to the water balance determination. The results obtained so far indicate on strong increasing trend of evapotranspiration and only very small, statistically insignificant, increase of precipitation. This causes a decrease of the water balance, defined as a difference between precipitation and evaporation. In Poland the water balance is positive in the cool part of the year and negative in the growing season. This causes that a water deficit in the growing season will be more and more stressful, especially since the injection of water from the snow cover before the growing season also significantly decreases. Heat waves will be distinguished basing on maximum daily air temperature. Their number, duration and intensity also have increased considerably from the middle of the twentieth century. The standardized precipitation-evaporation index (SPEI) by Vicente-Serrano and snow cover data from the winter preceding the drought will be used to find out reasons of simultaneous appearance of heat waves and drought. Among others factors will be considered: the North Atlantic Oscillation, the Arctic Oscillation, Arctic sea ice cover. The research is supported from the Polish National Science Centre (grant 2019/33/B/ST10/01136)

International Journal of Climatology, Jan 24, 2023

We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending... more We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending on sectors and seasons. In the Eurasian sector, the highest SIA reduction occurred in the last 15 years, whereas in the American sector, single years of low SIA were also observed in the last two decades of the 20th century and at the beginning of the 21st century. For years of the lowest SIA in the Eurasian sector, the strong warming in the Barents and Kara Seas (BKS) and cooling in central Asia is created, giving rise to the Warm Arctic Cold Eurasia (WACE) pattern development. The enhancement of high‐pressure centre over Asia and the formation of Ural Blocking follows these anomalies. After the low SIA in May–June in the Eurasian sector, in summer, the very strong Greenland Blocking is created, reaching the North Pole and the whole of Eurasia (only in August), increasing in magnitude with altitude, which gives much warmer conditions in the North American high‐latitude region (NAH), BKS, and Europe. For the years of the lowest SIA in the American sector, the Pacific High is much more developed and extended in the entire vertical profile. This strong positive anomaly brings colder weather in Alaska and the western United States. It is most apparent after low SIA in summer and autumn and is probably due to significant changes in sea ice cover over the Chukchi Sea during that time. At the same time, the Aleutian Low is deepened in the Kamchatka neighbourhood.

Prace Geograficzne

The aim of the study is to present changes in air humidity in central Poland in the years 1966–20... more The aim of the study is to present changes in air humidity in central Poland in the years 1966–2000 in Łódź as an example. The values of air temperature, relative humidity and atmospheric pressure from four observation terms, 00, 06, 12 and 18 UTC, were used. On this basis, the saturated vapour pressure, the current vapour pressure, and the saturation deficit were calculated. Then, the variability of these three indicators and relative humidity was examined. The variability of monthly and seasonal average values of humidity indices in four observation periods was presented, the trends in seasonal variability of humidity indices were calculated and the distribution functions of their distributions were compared in the midday period in three 15-year periods: 1966–1980, 1986–2000 and 2006–2020. It has been shown that the pressure of saturated water vapour is the highest in summer, the lowest in winter, and slightly higher in spring than in autumn at all times, except for the night. It ...

On the basis of data from the period 1966-2020 from about 50 stations in Poland the precipitation... more On the basis of data from the period 1966-2020 from about 50 stations in Poland the precipitation and potential evaporation indices will be estimated and their variability analyzed. Different formulas of potential evapotranspiration, based on air temperature, relative humidity, saturation deficit, wind speed and/or sunshine duration, will be compared. Climatic water balance defined as a difference of precipitation and potential evapotranspiration will be calculated and its intraannual variability analyzed. Long-term changes of all three parameters (precipitation, evapotranspiration and climatic water balance) in the context of contemporary warming will be examined. On this basis, the problem of water availability in various regions of the country will be discussed, especially in the context of changes in the spatial distribution and duration of the snow cover.

Prace i Studia Geograficzne, 2001

International Journal of Climatology

We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending... more We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending on sectors and seasons. In the Eurasian sector, the highest SIA reduction occurred in the last 15 years, whereas in the American sector, single years of low SIA were also observed in the last two decades of the 20th century and at the beginning of the 21st century. For years of the lowest SIA in the Eurasian sector, the strong warming in the Barents and Kara Seas (BKS) and cooling in central Asia is created, giving rise to the Warm Arctic Cold Eurasia (WACE) pattern development. The enhancement of high‐pressure centre over Asia and the formation of Ural Blocking follows these anomalies. After the low SIA in May–June in the Eurasian sector, in summer, the very strong Greenland Blocking is created, reaching the North Pole and the whole of Eurasia (only in August), increasing in magnitude with altitude, which gives much warmer conditions in the North American high‐latitude region (NAH), BK...

EGU General Assembly Conference Abstracts, Apr 1, 2016

EGU General Assembly Conference Abstracts, Apr 1, 2016

The spatial dependence of meteorological variables is crucial for many impacts, for example, drou... more The spatial dependence of meteorological variables is crucial for many impacts, for example, droughts, floods, river flows, energy demand, and crop yield. There is thus a need to understand how well it is represented in downscaling (DS) products. Within the COST Action VALUE, we have conducted a comprehensive analysis of spatial variability in the output of over 40 different DS methods in a perfect predictor setup. The DS output is evaluated against daily precipitation and temperature observations for the period 1979-2008 at 86 sites across Europe and 53 sites across Germany. We have analysed the dependency of correlations of daily temperature and precipitation series at station pairs on the distance between the stations. For the European data set, we have also investigated the complexity of the downscaled data by calculating the number of independent spatial degrees of freedom. For daily precipitation at the German network, we have additionally evaluated the dependency of the joint exceedance of the wet day threshold and of the local 90th percentile on the distance between the stations. Finally, we have investigated regional patterns of European monthly precipitation obtained from rotated principal component analysis. We analysed Perfect Prog (PP) methods, which are based on statistical relationships derived from observations, as well as Model Output Statistics (MOS) approaches, which attempt to correct simulated variables. In summary, we found that most PP DS methods, with the exception of multisite analog methods and a method that explicitly models spatial dependence yield unrealistic spatial characteristics. Regional climate model-based MOS methods showed good performance with respect to correlation lengths and the joint occurrence of wet days, but a substantial overestimation of the joint occurrence of heavy precipitation events. These findings apply to the spatial scales that are resolved by our observation network, and similar studies with higher resolutions, which are relevant for small hydrological catchment, are desirable.

Earth System Science Data Discussions, 2017

The CHASE-PL (Climate change impact assessment for selected sectors in Poland) Climate Projection... more The CHASE-PL (Climate change impact assessment for selected sectors in Poland) Climate Projections – Bias Corrected Daily Precipitation and Temperature dataset 5 km (CPLCP-GDPT5) consists of projected daily minimum and maximum air temperatures and precipitation totals of nine EURO-CORDEX regional climate model outputs bias corrected and downscaled to 5 × 5 km grid. Simulations of one historical period (1971–2000) and two future horizons (2021–2050 and 2071–2100) assuming two Representative Concentration Pathways (RCP4.5 and RCP8.5) were produced. We used the quantile mapping method and corrected any systematic bias in these simulations before assessing the changes in annual and seasonal means of precipitation and temperature over Poland. Projected changes estimated from the multi-model ensemble mean showed that annual means of temperature are expected to increase constantly by 1 °C until 2021–2050 and by 2&thinsp...

Daily precipitation totals and daily minimum and maximum temperatures from 21 Polish stations wer... more Daily precipitation totals and daily minimum and maximum temperatures from 21 Polish stations were used to calculate records of indices of temperature and precipitation extremes in the period 1951-2006. Because the distributions of extreme indices are generally far from normal, especially for indices defined as day counts, the popular trend estimators like linear trend calculated by the least mean squares method are not robust. The Kendall tau test and Sen's trend estimators were used and their results were compared with those obtained by more traditional methods. A statistically significant increase of annual frequencies of summer and hot days and the decrease in the frequencies of ice and frost days and in the length of the frost season has occurred in Poland. All percentiles of daily minimum and maximum temperature have increased also, but the increases of extreme percentiles (1, 5, 95 and 99) were not significant especially according to the Kendall tau test. Trends of monthl...

International Journal of Climatology

<p>The Arctic region has undergone a substantial climatic changes in recent years w... more <p>The Arctic region has undergone a substantial climatic changes in recent years with dramatic sea-ice loss, evident particularly in late summer and early autumn. According to many findings the near-surface temperature in high latitudes of the Northern Hemisphere has been rising at rates double that of the lower latitudes and was amplified by rapid loss of sea ice in the Arctic through the snow and ice albedo feedback. Open, free of ice water has a smaller albedo than ice, absorbs more energy incoming from the Sun, resulting in much faster increase in temperature than other areas. The abrupt acceleration in Arctic warming well seen since the middle 1990s coincides with changes in climate in the mid-latitudes. The aim of this paper is to analyse the changes in atmospheric circulation in the mid to high latitudes in the response to low extent of ice cover  in Arctic in the preceding months.</p><p>To analyze the variability of sea ice cover in Arctic region we used daily sea-ice fraction data which are defined as the fraction of a grid box which is covered by sea ice. These data were multiplied by field of each grid box. After summing up all recalculated grid points, a new parameter named – area ice cover (AIC) was defined. We analyzed the AIC variability in the whole Artcic and in three sectors Atlantic - from 75°W to 60°E, Asian - from 60.25°E to 189.75°W and American - from 170°W to 75.25°W.</p><p>Then AIC index was correlated to selected northern hemisphere teleconnection: North Atlantic Oscillation (NAO), the Scandinavian pattern (SCAND), East Atlantic (EA), Polar/Eurasia index (POL). The Monthly NAO, SCAND, EA and POL values were provided by U.S. National Centers for Environmental Prediction (NCEP). The AIC preceded circulation indices by 1 to 12 months.</p><p>In regions and periods of significant correlation, composite maps of temperature anomalies, sea level pressure and geopotential altitude of 100 and 200 hPa in the years with low icing were created and analysed.</p><p>The analysis showed that the greatest changes in AIC are observed in Asian sector of Arctic and they have the strongest impact on the atmospheric circulation. AIC changes modulate circulation in both winter and summer period. However the nature of the impact is clearly different. A sensitive regions turns to be Barents and Kara Seas and Novaya Zemlya.</p>

The book presents the results of climate research throughout Poland in the pre-instrumental perio... more The book presents the results of climate research throughout Poland in the pre-instrumental period (using proxy data), instrumental period (using mainly statistical methods, based on data from weather stations and grid data) and projected changes (using regional climate models). A total of 1100 years are covered, i.e. the period from about 1000 to 2100. The majority of examined climate elements, meteorological phenomena and indices show statistically significant changes at least in certain areas of Poland and at certain seasons of the year. Moreover, many elements demonstrate significant year-to-year variability and temporal fluctuations. Changes of particular climate elements are interrelated. The primary causative factors are both anthropogenic changes (greenhouse gas emissions resulting in increased greenhouse effect and global warming, local sources of air pollution) and natural changes: (1) circulation factors: changes in the intensity and location of atmospheric activity centr...

International Journal of Climatology, 2018

Acta Geographica Lodziensia, 2019

Precipitation in the Łódź Voivodeship in the period 1961-2015 Zarys treści. W pracy przedstawiono... more Precipitation in the Łódź Voivodeship in the period 1961-2015 Zarys treści. W pracy przedstawiono zmienność czasową i przestrzenną opadów w województwie łódzkim w latach 1961-2015. W tym celu wykorzystano dobowe sumy opadu z 20 posterunków opadowych na terenie województwa łódzkiego. Wykazano, że średnia roczna suma opadów w województwie wynosiła 582 mm, przy czym na poszczególnych stacjach wahała się od 515 do 648. Najwyższe wartości odnotowano w południowej części województwa, malały one jednak ku północy, gdzie niedobory opadów pojawiały się najczęściej. W biegu rocznym najwyższe sumy obserwowano latem, a najniższe zimą. Opady letnie były ponad dwukrotnie wyższe od zimowych. Natomiast opady wiosenne i jesienne utrzymywały się na podobnym poziomie, z lekką przewagą wiosennych. Dobowe sumy opadu najczęściej mieściły się w przedziale 1-10 mm. Opady przekraczające 50 mm były rzadkością i pojawiały się raz na kilka lat, głównie latem. Nie zaobserwowano istotnych statystycznie zmian struktury i wysokości opadów. Pojawiła się jednak niewielka tendencja wzrostowa sum zimowych i spadkowa sum letnich.

Climate Change in Poland, 2021

The wind was analyzed on the basis of speed and direction data from three observation times at 41... more The wind was analyzed on the basis of speed and direction data from three observation times at 41 meteorological stations in Poland from 1966–2018. The average annual and seasonal wind speeds and the incidence of atmospheric calms were calculated. Wind frequencies from different directions were determined using a 16-sector wind rose. Particular attention was paid to winds exceeding 8 ms−1. The seasonal and annual trends of strong winds were counted. The average wind speed was 3.6 ms−1 and ranged from 1.4 ms−1 in Zakopane to 12 ms−1 on Śniezka. On the daily scale, the highest wind speed appeared at noon. In the annual cycle, the average wind speed at noon was the highest in spring and in the other times in winter, the lowest was always in summer. Windless weather occurred most often in the morning (12.3% of observations), less often in the evening (8.3%) and the least often at noon (3.0%). The long-term average of the highest annual wind speed oscillated between 8.3 ms−1 in Tarnow and 42.5 ms−1 on Śniezka. Strong winds were most often recorded from the west, west southwest and west northwest directions. In southern Poland it was also the southern direction. The decreasing trends in annual and seasonal series of wind speed were observed in Poland as well as in other European countries. A number of authors attribute this trend to an increase in surface roughness.

Meteorology Hydrology and Water Management

Interpolation of precipitation data is a common practice for generating continuous, spatially-dis... more Interpolation of precipitation data is a common practice for generating continuous, spatially-distributed fields that can be used for a range of applications, including climate modeling, water resource management, and agricultural planning. To obtain the reference field, daily observation data from the measurement network of the Institute of Meteorology and Water Management-National Research Institute was used. In this study, we compared and combined six different interpolation methods for daily precipitation in Poland, including bilinear and bicubic interpolation, inverse distance weighting, distance-weighted average, nearest neighbor remapping, and thin plate spline regression. Implementations of these methods available in the R programming language (e.g., from packages akima, gstat, fields) and the Climate Data Operators (CDO) were applied. The performance of each method was evaluated using multiple metrics, including the Pearson correlation coefficient (RO) and the correspondence ratio (CR), but there was no clear optimal method. As an interpolated resulting field, a field consisting of the best interpolations for individual days was proposed. The assessment of daily fields was based on the CR and RO parameters. Our results showed that the combined approach outperformed individual methods with higher accuracy and reliability and allowed for generating more accurate and reliable precipitation fields. On a group of selected stations (data quality and no missing data), the precipitation result fields were compared with the fields obtained in other projects-CPLFD-GDPT5 (Berezowski et al. 2016) and G2DC-PLC (Piniewski et al. 2021). The variance inflation factor (VIF) was bigger for the resulting fields (~5), while for the compared fields, it was below 3. However, for the mean absolute error (MAE), the relationship was reversed-the MAE was approximately half as low for the fields obtained in this work.

Heat waves and droughts are two the most frequent weather extremes in Poland, both excerbated by ... more Heat waves and droughts are two the most frequent weather extremes in Poland, both excerbated by the ongoing global warming. Very often they occur simulateously. The aim of this presentation is identification of cases of simultaneous occurence of these extreme situations, examination of their spatial extent, frequency of occurrence and long-term variability. Reasons of their occurrence are also analysed. On the basis of data from the period 1966-2020 from about 40 stations in Poland reference evaporation indices will be estimated based on Palmer-Monteith formula and together with precipitation records used to the water balance determination. The results obtained so far indicate on strong increasing trend of evapotranspiration and only very small, statistically insignificant, increase of precipitation. This causes a decrease of the water balance, defined as a difference between precipitation and evaporation. In Poland the water balance is positive in the cool part of the year and negative in the growing season. This causes that a water deficit in the growing season will be more and more stressful, especially since the injection of water from the snow cover before the growing season also significantly decreases. Heat waves will be distinguished basing on maximum daily air temperature. Their number, duration and intensity also have increased considerably from the middle of the twentieth century. The standardized precipitation-evaporation index (SPEI) by Vicente-Serrano and snow cover data from the winter preceding the drought will be used to find out reasons of simultaneous appearance of heat waves and drought. Among others factors will be considered: the North Atlantic Oscillation, the Arctic Oscillation, Arctic sea ice cover. The research is supported from the Polish National Science Centre (grant 2019/33/B/ST10/01136)

International Journal of Climatology, Jan 24, 2023

We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending... more We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending on sectors and seasons. In the Eurasian sector, the highest SIA reduction occurred in the last 15 years, whereas in the American sector, single years of low SIA were also observed in the last two decades of the 20th century and at the beginning of the 21st century. For years of the lowest SIA in the Eurasian sector, the strong warming in the Barents and Kara Seas (BKS) and cooling in central Asia is created, giving rise to the Warm Arctic Cold Eurasia (WACE) pattern development. The enhancement of high‐pressure centre over Asia and the formation of Ural Blocking follows these anomalies. After the low SIA in May–June in the Eurasian sector, in summer, the very strong Greenland Blocking is created, reaching the North Pole and the whole of Eurasia (only in August), increasing in magnitude with altitude, which gives much warmer conditions in the North American high‐latitude region (NAH), BKS, and Europe. For the years of the lowest SIA in the American sector, the Pacific High is much more developed and extended in the entire vertical profile. This strong positive anomaly brings colder weather in Alaska and the western United States. It is most apparent after low SIA in summer and autumn and is probably due to significant changes in sea ice cover over the Chukchi Sea during that time. At the same time, the Aleutian Low is deepened in the Kamchatka neighbourhood.

Prace Geograficzne

The aim of the study is to present changes in air humidity in central Poland in the years 1966–20... more The aim of the study is to present changes in air humidity in central Poland in the years 1966–2000 in Łódź as an example. The values of air temperature, relative humidity and atmospheric pressure from four observation terms, 00, 06, 12 and 18 UTC, were used. On this basis, the saturated vapour pressure, the current vapour pressure, and the saturation deficit were calculated. Then, the variability of these three indicators and relative humidity was examined. The variability of monthly and seasonal average values of humidity indices in four observation periods was presented, the trends in seasonal variability of humidity indices were calculated and the distribution functions of their distributions were compared in the midday period in three 15-year periods: 1966–1980, 1986–2000 and 2006–2020. It has been shown that the pressure of saturated water vapour is the highest in summer, the lowest in winter, and slightly higher in spring than in autumn at all times, except for the night. It ...

On the basis of data from the period 1966-2020 from about 50 stations in Poland the precipitation... more On the basis of data from the period 1966-2020 from about 50 stations in Poland the precipitation and potential evaporation indices will be estimated and their variability analyzed. Different formulas of potential evapotranspiration, based on air temperature, relative humidity, saturation deficit, wind speed and/or sunshine duration, will be compared. Climatic water balance defined as a difference of precipitation and potential evapotranspiration will be calculated and its intraannual variability analyzed. Long-term changes of all three parameters (precipitation, evapotranspiration and climatic water balance) in the context of contemporary warming will be examined. On this basis, the problem of water availability in various regions of the country will be discussed, especially in the context of changes in the spatial distribution and duration of the snow cover.

Prace i Studia Geograficzne, 2001

International Journal of Climatology

We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending... more We found substantial differences in the atmospheric response to sea ice area (SIA) loss depending on sectors and seasons. In the Eurasian sector, the highest SIA reduction occurred in the last 15 years, whereas in the American sector, single years of low SIA were also observed in the last two decades of the 20th century and at the beginning of the 21st century. For years of the lowest SIA in the Eurasian sector, the strong warming in the Barents and Kara Seas (BKS) and cooling in central Asia is created, giving rise to the Warm Arctic Cold Eurasia (WACE) pattern development. The enhancement of high‐pressure centre over Asia and the formation of Ural Blocking follows these anomalies. After the low SIA in May–June in the Eurasian sector, in summer, the very strong Greenland Blocking is created, reaching the North Pole and the whole of Eurasia (only in August), increasing in magnitude with altitude, which gives much warmer conditions in the North American high‐latitude region (NAH), BK...

EGU General Assembly Conference Abstracts, Apr 1, 2016

EGU General Assembly Conference Abstracts, Apr 1, 2016

The spatial dependence of meteorological variables is crucial for many impacts, for example, drou... more The spatial dependence of meteorological variables is crucial for many impacts, for example, droughts, floods, river flows, energy demand, and crop yield. There is thus a need to understand how well it is represented in downscaling (DS) products. Within the COST Action VALUE, we have conducted a comprehensive analysis of spatial variability in the output of over 40 different DS methods in a perfect predictor setup. The DS output is evaluated against daily precipitation and temperature observations for the period 1979-2008 at 86 sites across Europe and 53 sites across Germany. We have analysed the dependency of correlations of daily temperature and precipitation series at station pairs on the distance between the stations. For the European data set, we have also investigated the complexity of the downscaled data by calculating the number of independent spatial degrees of freedom. For daily precipitation at the German network, we have additionally evaluated the dependency of the joint exceedance of the wet day threshold and of the local 90th percentile on the distance between the stations. Finally, we have investigated regional patterns of European monthly precipitation obtained from rotated principal component analysis. We analysed Perfect Prog (PP) methods, which are based on statistical relationships derived from observations, as well as Model Output Statistics (MOS) approaches, which attempt to correct simulated variables. In summary, we found that most PP DS methods, with the exception of multisite analog methods and a method that explicitly models spatial dependence yield unrealistic spatial characteristics. Regional climate model-based MOS methods showed good performance with respect to correlation lengths and the joint occurrence of wet days, but a substantial overestimation of the joint occurrence of heavy precipitation events. These findings apply to the spatial scales that are resolved by our observation network, and similar studies with higher resolutions, which are relevant for small hydrological catchment, are desirable.

Earth System Science Data Discussions, 2017

The CHASE-PL (Climate change impact assessment for selected sectors in Poland) Climate Projection... more The CHASE-PL (Climate change impact assessment for selected sectors in Poland) Climate Projections – Bias Corrected Daily Precipitation and Temperature dataset 5 km (CPLCP-GDPT5) consists of projected daily minimum and maximum air temperatures and precipitation totals of nine EURO-CORDEX regional climate model outputs bias corrected and downscaled to 5 × 5 km grid. Simulations of one historical period (1971–2000) and two future horizons (2021–2050 and 2071–2100) assuming two Representative Concentration Pathways (RCP4.5 and RCP8.5) were produced. We used the quantile mapping method and corrected any systematic bias in these simulations before assessing the changes in annual and seasonal means of precipitation and temperature over Poland. Projected changes estimated from the multi-model ensemble mean showed that annual means of temperature are expected to increase constantly by 1 °C until 2021–2050 and by 2&thinsp...

Daily precipitation totals and daily minimum and maximum temperatures from 21 Polish stations wer... more Daily precipitation totals and daily minimum and maximum temperatures from 21 Polish stations were used to calculate records of indices of temperature and precipitation extremes in the period 1951-2006. Because the distributions of extreme indices are generally far from normal, especially for indices defined as day counts, the popular trend estimators like linear trend calculated by the least mean squares method are not robust. The Kendall tau test and Sen's trend estimators were used and their results were compared with those obtained by more traditional methods. A statistically significant increase of annual frequencies of summer and hot days and the decrease in the frequencies of ice and frost days and in the length of the frost season has occurred in Poland. All percentiles of daily minimum and maximum temperature have increased also, but the increases of extreme percentiles (1, 5, 95 and 99) were not significant especially according to the Kendall tau test. Trends of monthl...

International Journal of Climatology

<p>The Arctic region has undergone a substantial climatic changes in recent years w... more <p>The Arctic region has undergone a substantial climatic changes in recent years with dramatic sea-ice loss, evident particularly in late summer and early autumn. According to many findings the near-surface temperature in high latitudes of the Northern Hemisphere has been rising at rates double that of the lower latitudes and was amplified by rapid loss of sea ice in the Arctic through the snow and ice albedo feedback. Open, free of ice water has a smaller albedo than ice, absorbs more energy incoming from the Sun, resulting in much faster increase in temperature than other areas. The abrupt acceleration in Arctic warming well seen since the middle 1990s coincides with changes in climate in the mid-latitudes. The aim of this paper is to analyse the changes in atmospheric circulation in the mid to high latitudes in the response to low extent of ice cover  in Arctic in the preceding months.</p><p>To analyze the variability of sea ice cover in Arctic region we used daily sea-ice fraction data which are defined as the fraction of a grid box which is covered by sea ice. These data were multiplied by field of each grid box. After summing up all recalculated grid points, a new parameter named – area ice cover (AIC) was defined. We analyzed the AIC variability in the whole Artcic and in three sectors Atlantic - from 75°W to 60°E, Asian - from 60.25°E to 189.75°W and American - from 170°W to 75.25°W.</p><p>Then AIC index was correlated to selected northern hemisphere teleconnection: North Atlantic Oscillation (NAO), the Scandinavian pattern (SCAND), East Atlantic (EA), Polar/Eurasia index (POL). The Monthly NAO, SCAND, EA and POL values were provided by U.S. National Centers for Environmental Prediction (NCEP). The AIC preceded circulation indices by 1 to 12 months.</p><p>In regions and periods of significant correlation, composite maps of temperature anomalies, sea level pressure and geopotential altitude of 100 and 200 hPa in the years with low icing were created and analysed.</p><p>The analysis showed that the greatest changes in AIC are observed in Asian sector of Arctic and they have the strongest impact on the atmospheric circulation. AIC changes modulate circulation in both winter and summer period. However the nature of the impact is clearly different. A sensitive regions turns to be Barents and Kara Seas and Novaya Zemlya.</p>

The book presents the results of climate research throughout Poland in the pre-instrumental perio... more The book presents the results of climate research throughout Poland in the pre-instrumental period (using proxy data), instrumental period (using mainly statistical methods, based on data from weather stations and grid data) and projected changes (using regional climate models). A total of 1100 years are covered, i.e. the period from about 1000 to 2100. The majority of examined climate elements, meteorological phenomena and indices show statistically significant changes at least in certain areas of Poland and at certain seasons of the year. Moreover, many elements demonstrate significant year-to-year variability and temporal fluctuations. Changes of particular climate elements are interrelated. The primary causative factors are both anthropogenic changes (greenhouse gas emissions resulting in increased greenhouse effect and global warming, local sources of air pollution) and natural changes: (1) circulation factors: changes in the intensity and location of atmospheric activity centr...

International Journal of Climatology, 2018

Acta Geographica Lodziensia, 2019

Precipitation in the Łódź Voivodeship in the period 1961-2015 Zarys treści. W pracy przedstawiono... more Precipitation in the Łódź Voivodeship in the period 1961-2015 Zarys treści. W pracy przedstawiono zmienność czasową i przestrzenną opadów w województwie łódzkim w latach 1961-2015. W tym celu wykorzystano dobowe sumy opadu z 20 posterunków opadowych na terenie województwa łódzkiego. Wykazano, że średnia roczna suma opadów w województwie wynosiła 582 mm, przy czym na poszczególnych stacjach wahała się od 515 do 648. Najwyższe wartości odnotowano w południowej części województwa, malały one jednak ku północy, gdzie niedobory opadów pojawiały się najczęściej. W biegu rocznym najwyższe sumy obserwowano latem, a najniższe zimą. Opady letnie były ponad dwukrotnie wyższe od zimowych. Natomiast opady wiosenne i jesienne utrzymywały się na podobnym poziomie, z lekką przewagą wiosennych. Dobowe sumy opadu najczęściej mieściły się w przedziale 1-10 mm. Opady przekraczające 50 mm były rzadkością i pojawiały się raz na kilka lat, głównie latem. Nie zaobserwowano istotnych statystycznie zmian struktury i wysokości opadów. Pojawiła się jednak niewielka tendencja wzrostowa sum zimowych i spadkowa sum letnich.

Climate Change in Poland, 2021

The wind was analyzed on the basis of speed and direction data from three observation times at 41... more The wind was analyzed on the basis of speed and direction data from three observation times at 41 meteorological stations in Poland from 1966–2018. The average annual and seasonal wind speeds and the incidence of atmospheric calms were calculated. Wind frequencies from different directions were determined using a 16-sector wind rose. Particular attention was paid to winds exceeding 8 ms−1. The seasonal and annual trends of strong winds were counted. The average wind speed was 3.6 ms−1 and ranged from 1.4 ms−1 in Zakopane to 12 ms−1 on Śniezka. On the daily scale, the highest wind speed appeared at noon. In the annual cycle, the average wind speed at noon was the highest in spring and in the other times in winter, the lowest was always in summer. Windless weather occurred most often in the morning (12.3% of observations), less often in the evening (8.3%) and the least often at noon (3.0%). The long-term average of the highest annual wind speed oscillated between 8.3 ms−1 in Tarnow and 42.5 ms−1 on Śniezka. Strong winds were most often recorded from the west, west southwest and west northwest directions. In southern Poland it was also the southern direction. The decreasing trends in annual and seasonal series of wind speed were observed in Poland as well as in other European countries. A number of authors attribute this trend to an increase in surface roughness.