Anthropogenically Determined Gorges of the Sumina and Wierzbnik Rivers as an Example of Naturalisation of Artificial River Channels (Ruda River Catchment)

The article describes anthropogenic transformations of relief features associated with former economic use of rivers and the changes that occurred in individual sections of artificial canals as a result of their naturalisation. The study was carried out in two river valleys – of the Sumina and Wierzbnik Rivers, which are located in the Ruda River catchment (within the Odra River drainage basin), on the boundary of the Rybnik Plateau and the Racibórz Basin. The use of water in these rivers for the purposes of former grain mills, sawmills and other industrial facilities as well as fish ponds involved the construction of bypasses. The deep erosion gullies recorded in the relief of the Sumina and Wierzbnik River valleys are in fact transformed anthropogenic forms: artificial river channels and old bypasses. In the Wierzbnik River valley, these canals – today dead, but still visible in relief, reflect the technical solutions which were once used to protect ponds from damage during floods. The sections of old artificial canals such as the man-made channel of the Sumina River, are still subject to naturalisation processes, being were later transformed by natural fluvial processes. This is reflected in an increase in channel sinuosity and the development of meanders. It is proposed that the erosive forms described in the article be referred to as anthropogenically determined river gorges.

Thermal conditions of the formation and persistence of ice cover on the River Noteć

The article presents the results of an analysis of the impact of cumulated series of negative air temperatures (cumulated degree-days) on the formation and persistence of the permanent ice cover on the River Noteć in the period 1987–2013. When assessing ice phenomena, use was made of observations conducted over 24-hour periods at four IMGW-PIB stations located along the River Noteć: Pakość (upper section), Ujście and Krzyż Wielkopolski (middle section) and Nowe Drezdenko (lower section). The authors determined the nature of the distribution of negative series and 24-hour air temperatures in terms of their duration, increase and distribution in years and months, using data from the Piła meteorological station. The primary objective was to specify the threshold values of cumulated degree-days at which the permanent ice cover starts to appear on the river, and the conditions under which this phenomenon is accelerated. When determining the strength of the relation between cumulated degree-days and the probability of appearance of an ice cover, use was made of the logistic regression model. Research showed that in the majority of instances ice cover appeared on the river at values of cumulated degree-days greater than: –16°C in Pakość, –21°C in Ujście and Krzyż Wielkopolski, and –73.5°C in Nowe Drezdenko. During the analysed period, 306 negative air temperature series occurred in the studief catchment area, with those lasting 5–10 days (76 of all instances) being predominant. As regards the River Noteć in Pakość, the logistic regression model confirmed that, on average, a one-degree increase in the value of cumulated degree-days is associated with an increase in the probability of  appearance of the permanent ice cover of approximately 2.10%, of approximately 1.17% in Ujście, of 2.72% in Krzyż Wielkopolski, and of approximately 5.70% in Nowe Drezdenko. The more rapid the increase in cumulated series of negative air temperatures, the greater the probability of ice cover appearing and persisting on the River Noteć. The  analysis pointed to the usefulness of the cumulated degree-days factor for predicting the appearance of ice cover on the river. The results obtained are significant for maintaining the economic and ecological function of the River Noteć. Information about the icing of the river has a practical dimension, among others as concerns identifying and minimising hazards connected with the occurrence of jams and ice-jam floods, which bring about enormous economic losses and constitute a threat to human life.

Spatial and temporal variability of atmospheric precipitation in Japan (1901–2015)

The purpose of the study is to characterize the spatial and temporal variability of precipitation in Japan. This article uses data from 55 stations from the years 1901–2015. Annual patterns and preconditions of rainfall were analyzed. The range of variations for individual stations, the time of maximum and minimum occurrence, and the coefficients of precipitation irregularity were calculated. The temporal variability of rainfall was investigated using the linear trend method, the significance of which was determined by the tau-Kendall coefficient.The precipitation pattern in Japan shows a very strong variation throughout the country. The largest variability of annual precipitation totals is in the Hokuriku, Shikoku area along the Pacific Ocean and southeastern Kyushu with the archipelago of the Ryuku islands. The maximum monthly precipitation figures show a greater variability than the minimum values, and the time of their occurrence in each region is conditioned by the monsoon circulation and the location to the flow of major air masses and  orographic barriers. Japan is characterized by a statistically insignificant decrease in the annual rainfall in most areas, but the variability of precipitation in different months and seasons shows different directions and the rate of change depending on the region.

Impact of atmospheric circulation on air temperature in Warsaw during months with extreme values of the NAO index (1951–2015)

In winter, western air masses arriving in Europe, including Poland, change the weather for relatively warmer, while an eastern advection tends to bring freezing temperatures. While the NAO provides a quantitative measure of this western advection, its relationship with air temperature is not always clear-cut. For this reason, this study characterises the circulation and thermal conditions over Poland depending on the sign and the value of the NAO index (NAO+, NAO–).
The study is based on NAO values and winter (December – March) monthly temperature records in Warsaw spanning 65 years (1951–2015), as well as on the calendar of circulation types proposed by Lityński. A detailed analysis was performed looking at the top 10 months with the highest NAO+ and NAO–, as well as the top 10 months with the greatest positive and negative deviations from the long-term average air temperature (Dt). This selection was based on a premise that the months should largely coincide. The results, however, show certain deviations from previously established patterns in the influence of the NAO+/NAO– on air temperature in Poland.

Evaluation of bioclimatic conditions for selected forms of recreation and tourism in Eastern Poland

In this paper authors present an evaluation of bioclimatic conditions in the eastern part of Poland in regard to selected forms of recreation and tourism. For this purpose the biothermal-meteorological weather classification by K. Błażejczyk was used. Meteorological data for the period 1981–2015 were obtained from the Institute of Meteorology and  Water Management meteorological stations at Białystok, Lublin-Radawiec and Lesko. It was found that in Eastern Poland the most favourable conditions for sunbathing (SB) and aerotherapy (AB) occur from mid-April to mid-October, but in Lesko better conditions for these recreation  types are more frequent during the autumn moths. As for mild forms of recreation (MR) weather conditions are favourable more often during the year in Lesko than in Lublin or Białystok. As for intense activity (AR), favourable weather conditions occur during most days of the year. The type of recreation favoured by weather conditions in Eastern Poland for the shortest period of the year is ski tourism (ST). In Lublin and Białystok this period lasts from the beginning of February to the first decade of March. In Lesko the ski tourism season begins at the end of December and it is twice as long as in the other stations.

In the 20th century Wałbrzych and its surroundings was the most prominent area of coal mining in the Sudetes. Nevertheless, in 1997 the mines were closed. An intensive anthropogenic geomorphic cycle commenced there in 1865 and lasted for 130 years. The biggest transformations in landforms occurred in two basins: Wałbrzych and Kuźnice, where a complex of anthropogenic forms was created from dumps and settling ponds, as well as subsidence depression. Among the dominant geomorphic processes related to anthropopressure were anthropogenic aggradation and anthropogenic denudation. Those processes resulted in raising and lowering of the land surface. Their intensity was diverse both in time and space. The average pace of anthropogenic aggradation in the years 1865–1996 amounted to 328 mm/year and was higher in the years 1945–1996 (439 mm/year) than during the period from 1865 to 1944 (255 mm/year). In both basins: Wałbrzych and Kuźnice, there was an increase in the intensity of this process in the years 1945–1996 when compared to the period of 1865–1944. The pace of anthropogenic denudation in the Wałbrzych coal mining area was considerably lower than the intensity of anthropogenic aggradation. During the research period, the land surface lowered, on average, by 66 mm/year, whereas the pace of the process decreased from 75 mm/year in the years 1865–1944 to 57 mm/year in the period 1945–1996. A considerably higher intensity of anthropogenic denudation was noted the Wałbrzych Basin (96 mm/year) than in the Kuźnice Basin (36 mm/year). It was determined that the anthropogenic denudation balance in the in the Wałbrzych coal mining area in the years 1865–1996 was positive (+262 mm/year). When comparing the scale of anthropogenic aggradation and denudation in several coal mining areas (Wałbrzych, Upper Silesia, Ostrava-Karvina and Ruhr), it needs to be emphasized that in the research area the intensity of those processes in the period 1865–1996 was similar and, at times, higher than in the other areas, which results from the preference of cumulating of gangue on spoil tips as the cheapest way of its disposal, as well as from the dominance of caving coal extraction.