Przegląd Geograficzny (2022) tom 94, zeszyt 4

Abstract

The origins of talus slopes origin are connected with both weathering and the transport of rock grain. Slope formation in these landforms reflects many climatological, morphological and geological factors, with grain-size dsitributions characterising the surface of talus slopes able to offer some information on means of transport and deposition mechanisms. The main aim of the work detailed here has thus been to present disparate processes of talus-slope formation in two mountain locations – in zones of Arctic periglacial and semi-arid Continental periglacial climate.

Results for the two study sites are presented. The first is located on Spitsbergen, on its SW coast, near the Polish Polar Station. The climate there is Arctic and periglacial, the average annual temperature being -3.2°C and mean annual precipitation 494.6 mm. The slope here has a western exposure, with the rock face and talus slope built of gneiss and crystalline shales with marble intrusions. There is permafrost as well as an active layer noted at this study site. The second study site is in the Fann Mountains, which form part of the Pamiro-Allay Massif in Tajikistan. Annual temperature there is of about 1‑2°C (nearby Stations reporting 6.6°C at Iskanderkul at 2204 m a.s.l., and 0.7°C at the Shahristan Pass at 3143 m a.s.l.), while annual precipitation is some 300 mm. The slope has a southerly exposure, while the rock material is a massive Devonian limestone. No permafrost is to be observed in this area.

Similar methods were used at both study sites, as Profiles featuring four measurement points were designated. At these points, 0.5 x 0.5 m squares were marked, and perpendicular photographs taken at a distance of 1.5 m. Composition as regards grain-size was analysed using BaseGRAIN software.

Structure as regards grain-size is seen to differ strongly between the two talus slopes. On Spitsbergen, grain-size is steadily greater at higher points up the slope. Close to the rock cliff it is boulders and large stones that dominate, while on the lowest parts it is grain-sizes classifiable as sand and silt that account for the greater part of the deposit. In the semi-arid climate of Asia, grain size proves to be sorted in the opposite way, with the largest debris fragments characterising the lowest parts of the talus slope. Close to the rock cliff, at the highest elevations, grains are of the smallest size, and are mostly assignable to the gravel and small stone categories. It is at the foot of the slope that rock sizes are the largest.

The most important factor underpinning the disparate formation of these two talus slopes is permafrost. Talus-slope structure in the Arctic reflects mutually-interrelated processes. Those concerning gravity related to the melting of permafrost with larger stones dislocated to the surface. Additionally, melting of the active layer and the presence of a roof of permafrost allows flowing water deriving from rain and snowmelt to bring about the intensive transport of particles of sand and silt sizes down to the lower part of the slope.

In the periglacial high-mountain conditions noted in Asia, the lack of permafrost combined with the low level of precipitation to minimise the factor of water here. The dominance of gravitational processes in the sorting material ensures that heaviest rock fragments are transported for longer, and end up being deposited in lower positions on the slope.

Keywords: talus slopes, grain size, Spitsbergen, Fann Mountains, periglacial zone

Piotr Dolnicki [piotr.dolnicki@up.krakow.pl], Uniwersytet Pedagogiczny, Instytut Geografii
Paweł Kroh [pawel.kroh@up.krakow.pl], Uniwersytet Pedagogiczny, Instytut Geografii

Citation

APA: Dolnicki, P., & Kroh, P. (2022). Skład frakcjonalny stożków gruzowych w kontekście zróżnicowanego klimatu peryglacjalnych stoków górskich (na przykładzie Spitsbergenu i środkowej Azji). Przegląd Geograficzny, 94(4), 437-450. https://doi.org/10.7163/PrzG.2022.4.2
MLA: Dolnicki, Piotr, and Kroh, Paweł. "Skład frakcjonalny stożków gruzowych w kontekście zróżnicowanego klimatu peryglacjalnych stoków górskich (na przykładzie Spitsbergenu i środkowej Azji)". Przegląd Geograficzny, vol. 94, no. 4, 2022, pp. 437-450. https://doi.org/10.7163/PrzG.2022.4.2
Chicago: Dolnicki, Piotr, and Kroh, Paweł. "Skład frakcjonalny stożków gruzowych w kontekście zróżnicowanego klimatu peryglacjalnych stoków górskich (na przykładzie Spitsbergenu i środkowej Azji)". Przegląd Geograficzny 94, no. 4 (2022): 437-450. https://doi.org/10.7163/PrzG.2022.4.2
Harvard: Dolnicki, P., & Kroh, P. 2022. "Skład frakcjonalny stożków gruzowych w kontekście zróżnicowanego klimatu peryglacjalnych stoków górskich (na przykładzie Spitsbergenu i środkowej Azji)". Przegląd Geograficzny, vol. 94, no. 4, pp. 437-450. https://doi.org/10.7163/PrzG.2022.4.2

Abstract

Contemporary challenges in the management of stormwater and modelling of rainfall-runoff processes (in urban areas in particular) require the use of rainfall-estimation devices more advanced than rain gauges. One such device is the laser disdrometer, which allows (alongside radar reflectivity) for measurement of the intensity of rainfall of high temporal resolution and an accuracy greater than that available using rain gauges. On the other hand, meteorological radar makes it possible to estimate rainfall with a high degree of spatial resolution. The disadvantage of radar observations is the inaccuracy of the rainfall data obtained.

Measurements of atmospheric precipitation conducted at the WULS-SGGW Meteorological Station in Warsaw in the years 2012‑2014 and 2019‑2020, using a tipping-bucket rain gauge and the laser disdrometer (Parsivel), were combined with data obtained from the meteorological radar in Legionowo (in the C-band), with this allowing data to be collected to allow for assessment of the usefulness of the disdrometer and radar where the estimation of rainfall is concerned. The two instruments have independent systems by which to record precipitation data, ensuring a mutual time shift. This made temporary synchronisation a necessity.

The data for the entire study period were used in analysing correlations between 24‑hour rainfall depths estimated on the basis of the rain gauge, on the one hand; and the disdrometer on the other. The correlation coefficient R obtained was equal to 0.87. However, the total amount of rainfall calculated on the basis of the data from the disdrometer was about 40% greater than the corresponding value from the rain gauge.

From the dataset for the years 2012‑2014, 21 individual events were selected for further analysis, with these being ones for which radar-estimated rainfall data in the form of a PAC hydrological product generated by the system belonging to Poland’s Institute of Meteorology and Water Management (IMGW-PIB) were also available. The data measured using the rain gauge and the disdrometer were characterised by a high time resolution, of 1 min. The rainfall-intensity values obtained from the PAC product had a temporal resolution of 10 min and a spatial resolution of 1 km. The rainfall data from the disdrometer and radar were then used in analysing the correlations between these and corresponding measurements made by rain-gauge. The mean and median values of the R correlation coefficient, obtained in these analyses on the basis of rainfall-intensity values averaged over 10-min time intervals (though observed at the basic 1-min resolution) were, when estimated using the disdrometer, of 0.98 and 0.99 respectively. Correlations based around rainfall-intensity values at the 1-min level of resolution only assumed lower values. The adequate values of the R coefficient, as determined for the radar data, were of 0.68 and 0.77 respectively.

The study also extended to include comparison of total values estimated for 21 individual rainfall events using the disdrometer and radar (the PAC hydrological product), as compared with data measured using the rain gauge. The analysed values from the disdrometer were greater than the corresponding rain-gauge values for almost all events, while those obtained using radar were lower in most cases. The mean and median values of the relative error, obtained in relation to the values of rainfall totals measured using the disdrometer, were 35.2 and 38.3% respectively. The relative error values, obtained in adequate analysis based around data from the PAC radar product, proved to be much higher, and amounted to 49.1 and 59.1% respectively. This analysis therefore made it clear how disdrometer- and radar-based data require prior correction before any potential use can be made of them, e.g. in hydrological analyses.

This paper’s simple method of adjusting the heights of rainfall estimated on the basis of the disdrometer at specific (assumed 10-min) time intervals during the event was able to achieve a significant reduction of differences in the total rainfall values for single events, as supplied by data from the disdrometer and the rain gauge. In regard to the adjusted data from the disdrometer, the mean and median values for relative error were of 15.5 and 17.6% respectively, in respect of the 12 rainfall events used to verify the method.

Keywords: tipping-bucket rain gauge, laser disdrometer, meteorological radar, hydrology, rainfall intensity and totals, correlation of rainfall data

Mariusz Paweł Barszcz [mariusz_barszcz@sggw.edu.pl], Szkoła Główna Gospodarstwa Wiejskiego w Warszawie, Instytut Inżynierii Środowiska

Citation

APA: Barszcz, M. (2022). Ocena przydatności disdrometru laserowego i radaru meteorologicznego do szacowania wielkości opadów deszczu. Przegląd Geograficzny, 94(4), 451-470. https://doi.org/10.7163/PrzG.2022.4.3
MLA: Barszcz, Mariusz Paweł. "Ocena przydatności disdrometru laserowego i radaru meteorologicznego do szacowania wielkości opadów deszczu". Przegląd Geograficzny, vol. 94, no. 4, 2022, pp. 451-470. https://doi.org/10.7163/PrzG.2022.4.3
Chicago: Barszcz, Mariusz Paweł. "Ocena przydatności disdrometru laserowego i radaru meteorologicznego do szacowania wielkości opadów deszczu". Przegląd Geograficzny 94, no. 4 (2022): 451-470. https://doi.org/10.7163/PrzG.2022.4.3
Harvard: Barszcz, M. 2022. "Ocena przydatności disdrometru laserowego i radaru meteorologicznego do szacowania wielkości opadów deszczu". Przegląd Geograficzny, vol. 94, no. 4, pp. 451-470. https://doi.org/10.7163/PrzG.2022.4.3

Abstract

This paper focuses on the restoration of forest ecosystems highlighting the importance of valuable ecological features. The focus is furthermore on a global perspective, with analyses taking in the main aspects of forest degradation and restoration from both theoretical and practical standpoints. Particular emphasis is placed on environmental policy as pursued currently, first and foremost in regard to the main instrument of ecosystem restoration that is constituted by the United Nations’ Decade thereof, running from 2021‑2030 (in accordance with UN Resolution A/Res/73/284). The article points to the linkage between policies seeking to counteract forest degradation on the one hand, and on the other to achieve the conservation of biodiversity, the protection of land, and both mitigation of and adaptation to climate change. Stress is further placed on an appropriate hierarchy of strategies seeking to improve the state of the world’s forests. While conservation, restoration and reforestation are the three main directions to Sustainable Forest Management, it is the first of the three that must always be emphasised first and foremost.

The study work at the heart of this article highlights a need for worldwide acceleration of the processes restoring forest ecosystems. Following the logic of interrelations between degradation and restoration, the problem of ecosystem degradation is first turned to, with an analysis of global deforestation also incorporated. Trends as regards the loss of forest and of tree cover in general over in the last 30 years are presented, with the basis for this examination being data from the FAO’s Forest Resource Assessment and Global Forest Watch. Furthermore, forest degradation and deforestation have been proceeding to an advanced degree in recent decades. In this way major losses have afflicted tropical forests and the so-called Intact Forest Landscapes. Importantly, many international commitments have now been taken on, with ambitious targets set in regard to the need for both deterioration of forest and the loss of tree cover to be stemmed. However, as the New York Declaration on Forests and other instruments make clear, most of the targets set for 2020 were not actually achieved.

In its consideration of the theoretical foundations of forest-ecosystem restoration, this paper reflects upon resilience, the recovery of native ecosystems, and the process of natural regeneration. The main contemporary paradigms to the theory and practice of forest-ecosystem restoration are here demonstrated, with the basis of the enquiry being formulae for the restoration of ecosystems elaborated by the Society of Ecological Restoration. Quite a large part of the study has been devoted to the Forest Landscape Restoration approach, with a presentation of the main FLR options as elaborated by the FLR Global Partnership. Two dominant types of FLR (‘wide-scale’ and ‘mosaic restoration’) are here integrated, while examples of challenging actions in the field of forest-ecosystem restoration have been provided, including AFR100, The Great Green Wall for the Sahara and Sahel, the 20 x 20 Initiative, and the Trillion Trees Campaign. Taking into account the importance of the latest EU activity in the field of nature protection, remarks are made in regard to the 2022 Nature Restoration Law.

The discussion brings to light certain aspects of criticism vis-à-vis the pursuit of forest restoration, which are to be found in the subject literature. This signals a problem of the conservation of forests being overshadowed by careless application of activities driven by climate-change policies. As numerous scientists demonstrate (see e.g. the Kew Declaration on reforestation…, 2021), this practice frequently leads to the mass-planting of fast-growing trees of exotic species, sometimes even invasive. In this way a threat may actually be posed to the ecological richness and valuable landscape features the given area possesses.

Indeed, the present study underlines repeatedly the significance of natural and native ecosystems. However it also puts emphasis on the multi-purpose nature of the effort, the need for a holistic approach to be taken, and the importance of context as projects seeking the restoration of forest ecosystems are planned and implemented.

Keywords: ecosystem degradation, forest protection, environmental policy, the Earth

Barbara Bożętka [origeo@interia.pl], Uniwersytet Mikołaja Kopernika w Toruniu

Citation

APA: Bożętka, B. (2022). Przywracanie ekosystemów leśnych – cele i założenia działań globalnych w kontekście Dekady Przywracania Ekosystemów (2021‑2030) ONZ. Przegląd Geograficzny, 94(4), 471-501. https://doi.org/10.7163/PrzG.2022.4.4
MLA: Bożętka, Barbara. "Przywracanie ekosystemów leśnych – cele i założenia działań globalnych w kontekście Dekady Przywracania Ekosystemów (2021‑2030) ONZ". Przegląd Geograficzny, vol. 94, no. 4, 2022, pp. 471-501. https://doi.org/10.7163/PrzG.2022.4.4
Chicago: Bożętka, Barbara. "Przywracanie ekosystemów leśnych – cele i założenia działań globalnych w kontekście Dekady Przywracania Ekosystemów (2021‑2030) ONZ". Przegląd Geograficzny 94, no. 4 (2022): 471-501. https://doi.org/10.7163/PrzG.2022.4.4
Harvard: Bożętka, B. 2022. "Przywracanie ekosystemów leśnych – cele i założenia działań globalnych w kontekście Dekady Przywracania Ekosystemów (2021‑2030) ONZ". Przegląd Geograficzny, vol. 94, no. 4, pp. 471-501. https://doi.org/10.7163/PrzG.2022.4.4

Abstract

Ongoing changes in climate (increases in air temperature, changes in the distribution of precipitation over the year) exert an influence on the genesis of watercourse supply, as expressed in relation to the three sources represented by rain, snowmelt and groundwater. In that context, to the work detailed here had as its aim the spatial and temporal determination of the structure (and trends) characterising winter hydrological half‑year runoff from selected river catchments in the Western Carpathians, in the assumed circumstances of a changing climate and growing anthropopressure. To ensure adequate characterisation of the situation, the study took in four drainage basins, representing both the Beskid Mountains as such (in the catchments of the Soła and Osława), as well as their Foothills (in the catchments of the Skawinka and Stobnica). It was in relation to these four watercourses that the nature of the supply was determined over the 40‑year (1981‑2020) period, in regard to mean daily flows in the profiles closing the selected catchments. Interpretation of the nature of supply was made possible by meteorological data concerning precipitation totals and types, thickness of snow cover and air temperature. Mean values for winter half‑year precipitation totals (P_WHY) ranged from 226.5 mm (Skawinka) to 440.6 mm (Soła). The share of annual total precipitation (P_A) accounted for by P_WHY ranged on average from 30.1% (Skawinka) to 43.9% (Soła). The average winter half‑year totals for snowfall (SF) in the study period ranged from 104.8 mm (Skawinka) to 313.4 mm (Soła). It was thus in the latter two catchments that the extreme shares of overall precipitation in the winter hydrological half‑year accounted for by snowfall were to be found, at 30.9% and 43.7% respectively. Average values for runoff in the winter half‑year (H_WHY) ranged from 150.3 mm (in the Skawinka catchment) to 348.8 mm (in the Osława catchment), while the share of annual outflow (H_A) accounted for by H_WHY averaged between 50.9% (Soła) and 60.4% (Stobnica). The 1981‑2020 period was not found to be characterised by any statistically significant directions of change in H_WHY, though negative H_WHY trends could be noted for all the catchments studied in regard to the years since 2000, with the range of relevant values being 4‑7 mm∙year^‑1. The 4 catchments showed a diversity of dominant sources of supply in H_WHY. In the case of the Soła, it was supply by snowmelt that took the largest (40.1%) share, while in the Osława supply by rainfall prevailed (at 38.0%), and in the Skawinka supply by groundwater (on 43.4%). The catchment of the Stobnica featured more or less equal shares of alimentation by precipitation and ground supply (at around 36‑38% in each case). All 4 catchments manifested declines over time in snowmelt‑induced runoff, albeit with these ranging from 0.3 mm∙yr^‑1 (Skawinka) to 1.2 mm∙yr^‑1 (Soła), while the role of supply involving groundwater is seen to be on the increase by between 0.17 mm∙yr^‑1 (Skawinka) and 1.04 mm∙yr^‑1 (Osława). In addition, the trend for increase in ground supply was found to be several times more distinct in the catchments of the Beskids as such, compared with their foothills, with marked spatial differentiation being the feature. In the catchments present in the foothills, the increase in ground supply proved similar, regardless of location.

Changes in land cover can be regarded as affecting the magnitudes of values for the α runoff coefficient for the WHY. Average values were lower in the foothills catchments: Stobnica (64%) and Skawinka (67%). In the catchments located in the Beskids per se, the average a values proved to be higher, with differences between catchments also greater (Soła on 72% and Osława on 94%).The negligible change over the study period when it came to the Skawinka catchment could be related to a 5‑fold increase in built‑up areas, even as the most‑major reduction in the runoff coefficient noted in the catchment of the Stobnica, was attributable to a reduction in the share of arable land from 61.0% (in 1990) to 46.4% (in 2018), with a concomitant increase in forest cover from 32.1 to 43.4%. Study of the α runoff coefficient attributable to rain revealed regional variations. While a downward trend characterised the eastern part of the research area (i.e. the Stobnica and Osława catchments), the trend was upward in the western part (where the Soła is located). It was notable how a downward trend for values of the α runoff coefficient either arose or intensified in all catchments across the 1999‑2020 sub‑period. Furthermore, the whole 40‑year study period did witness a downward trend for values of the coefficient for runoff attributable to snowfall in all 4 catchments, with this intensifying further in the 1999‑2020 sub‑period (hence in the same way as with the coefficient for rain‑related runoff).

The research results presented here attest to progressive increases in air temperature affecting precipitation types and totals, and thus also activity as regards the differentforms of watercourse supply in water. To this extent the working hypothesis established gained confirmation empirically, with demonstrably declining magnitudes and shares of river runoff accounted for by the thawing of snow and ice.

Keywords: snowfall, river runoff, winter hydrological half-year, Western Carpathians

Witold Bochenek [witold.bochenek@zg.pan.krakow.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Św. Jana 22, 31-018 Kraków, Poland
Małgorzata Kijowska-Strugała [mkijowska@zg.pan.krakow.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences 38-311 Szymbark 430: Poland e-mail: mkijowska@zg.pan.krakow.pl

Citation

APA: Bochenek, W., & Kijowska-Strugała, M. (2022). Zmiany w strukturze odpływu wody ze zlewni karpackich w półroczu hydrologicznym zimowym w latach 1981‑2020. Przegląd Geograficzny, 94(4), 503-519. https://doi.org/10.7163/PrzG.2022.4.5
MLA: Bochenek, Witold, and Kijowska-Strugała, Małgorzata. "Zmiany w strukturze odpływu wody ze zlewni karpackich w półroczu hydrologicznym zimowym w latach 1981‑2020". Przegląd Geograficzny, vol. 94, no. 4, 2022, pp. 503-519. https://doi.org/10.7163/PrzG.2022.4.5
Chicago: Bochenek, Witold, and Kijowska-Strugała, Małgorzata. "Zmiany w strukturze odpływu wody ze zlewni karpackich w półroczu hydrologicznym zimowym w latach 1981‑2020". Przegląd Geograficzny 94, no. 4 (2022): 503-519. https://doi.org/10.7163/PrzG.2022.4.5
Harvard: Bochenek, W., & Kijowska-Strugała, M. 2022. "Zmiany w strukturze odpływu wody ze zlewni karpackich w półroczu hydrologicznym zimowym w latach 1981‑2020". Przegląd Geograficzny, vol. 94, no. 4, pp. 503-519. https://doi.org/10.7163/PrzG.2022.4.5