The geometry of space-time prisms with uncertain anchors     

Bart Kuijpers  Walied Othman 《International journal of geographical information science》2017,31(9):1722-1748

Space-time prisms envelop all spatio-temporal locations that moving objects may have visited between two of their known spatio-temporal locations, given a bound on their travel speed. In this context, the known locations are often the result of observations or measurements, and they are called ‘anchor points’. The classic space-time prism, in isotropic two-dimensional space, as well as in transportation networks, assumes that the measurements of these anchor points are exact. Whereas, in many applications, we can assume that time can be measured fairly precisely, this assumption is unrealistic for the spatial components of measured locations (we think of Global Positioning System (GPS) errors, for instance). In this paper, we extend the classical prism from anchor points to circular ‘anchor regions’ that capture the uncertainty or error on their measurement. We define the notion of a space-time prism with uncertain anchor points, called uncertain prism, for short. We study the geometry of uncertain prisms in an arbitrary metric space to make this concept as widely applicable as possible. We also focus on the rims of uncertain space-time prisms, which demarcate the area that a moving object can have visited between two anchor regions (given some local speed limitations).  相似文献   

Sea water surface energy balance in the Arctic fjord (Hornsund,SW Spitsbergen) in May–November 2014     

Fortuniak  Krzysztof  Przybylak  Rajmund  Araźny  Andrzej  Pawlak  Włodzimierz  Wyszyński  Przemysław 《Theoretical and Applied Climatology》2017,130(3-4):959-970

Maize is grown by millions of smallholder farmers in South Asia (SA) under diverse environments. The crop is grown in different seasons in a year with varying exposure to weather extremes, including high temperatures at critical growth stages which are expected to increase with climate change. This study assesses the impact of current and future heat stress on maize and the benefit of heat-tolerant varieties in SA. Annual mean maximum temperatures may increase by 1.4–1.8 °C in 2030 and 2.1–2.6 °C in 2050, with large monthly, seasonal, and spatial variations across SA. The extent of heat stressed areas in SA could increase by up to 12 % in 2030 and 21 % in 2050 relative to the baseline. The impact of heat stress and the benefit from heat-tolerant varieties vary with the level of temperature increase and planting season. At a regional scale, climate change would reduce rainfed maize yield by an average of 3.3–6.4 % in 2030 and 5.2–12.2 % in 2050 and irrigated yield by 3–8 % in 2030 and 5–14 % in 2050 if current varieties were grown under the future climate. Under projected climate, heat-tolerant varieties could minimize yield loss (relative to current maize varieties) by up to 36 and 93 % in 2030 and 33 and 86 % in 2050 under rainfed and irrigated conditions, respectively. Heat-tolerant maize varieties, therefore, have the potential to shield maize farmers from severe yield loss due to heat stress and help them adapt to climate change impacts.  相似文献   

The urban heat island in the city of Poznań as derived from Landsat 5 TM     

Majkowska  Agnieszka  Kolendowicz  Leszek  Półrolniczak  Marek  Hauke  Jan  Czernecki  Bartosz 《Theoretical and Applied Climatology》2017,127(3-4):769-777

Deforestation is expanding and accelerating into the remaining areas of undisturbed forest, and the quality of the remaining forests is declining today. Assessing the climatic impacts of deforestation can help to rectify this alarming situation. In this paper, how historical deforestation may affect global climate through interactive ocean and surface albedo is examined using an Earth system model of intermediate complexity (EMIC). Control and anomaly integrations are performed for 1000 years. In the anomaly case, cropland is significantly expanded since AD 1700. The response of climate in deforested areas is not uniform between the regions. In the background of a global cooling of 0.08 °C occurring with cooler surface air above 0.4 °C across 30° N to 75° N from March to September, the surface albedo increase has a global cooling effect in response to global-scale replacement of forests by cropland, especially over northern mid-high latitudes. The northern mid-latitude (30° N–60° N) suffers a prominent cooling in June, suggesting that this area is most sensitive to cropland expansion through surface albedo. Most regions show a consistent trend between the overall cooling in response to historical deforestation and its resulting cooling due to surface albedo anomaly. Furthermore, the effect of the interactive ocean on shaping the climate response to deforestation is greater than that of prescribed SSTs in most years with a maximum spread of 0.05 °C. This difference is more prominent after year 1800 than that before due to the more marked deforestation. These findings show the importance of the land cover change and the land surface albedo, stressing the necessity to analyze other biogeophysical processes of deforestation using interactive ocean.  相似文献   

Fungal air contamination in distinct sites within a municipal landfill area     

K. Frączek  J. Kozdrój  R. L. Górny  M. Cyprowski  M. Gołofit-Szymczak 《International Journal of Environmental Science and Technology》2017,14(12):2637-2648

Municipal wastes collected in landfills are a significant source of air contamination and frequently characterize by elevated concentrations of different fungi. Posing a serious health threat to landfill workers and local residents, the fungal aerosol has to be monitored with respect to its quantity and quality. In this study, concentrations of airborne fungi, their particle size distribution, species composition and the presence of cytotoxic strains of Aspergillus fumigatus were assessed in different sites within the landfill area. The quantitative and qualitative changes in the fungal aerosol were determined with respect to a season and landfill activity level (i.e. exploitation or standstill periods). Within the landfill area, particular sites were grouped with regard to airborne fungi concentrations and similarities in species composition. The qualitative analysis indicated that 43 species were shared during both sampling times, and only nine species were characteristic for the standstill period. Among fungal isolates, 21 strains of A. fumigatus revealed cytotoxic activity expressed at different levels, depending on the fungal extract concentrations used in the MTT assay. The results suggested that exposure (especially in summer) to small airborne particles, containing distinct species, may occur not only in the active sector but also in close vicinity to the landfill. Hence, microbial monitoring of the landfill and surrounding area should be carried out taking into account both quantitative aspect supplemented by size distribution analysis and qualitative features, especially of those strains possessing cytotoxic activity.  相似文献   

Characteristics of airborne bacteria and fungi in some Polish wastewater treatment plants     

M. Kowalski  J. Wolany  J. S. Pastuszka  G. Płaza  A. Wlazło  K. Ulfig  A. Malina 《International Journal of Environmental Science and Technology》2017,14(10):2181-2192

The aim of this study was to characterize both the viable airborne bacteria and fungi collected in different types of wastewater treatment plants in Poland. Bacterial and fungal aerosols in five different wastewater treatment plants in Poland were studied, including the pioneering antibiotic resistance testing of airborne bacteria. Concentration level was measured using the six-stage Andersen impactor. After incubation, bioaerosol particles captured on nutrient media on Petri dishes were quantitatively evaluated and qualitatively identified. It was found that the concentration levels of both airborne bacteria and fungi ranged from 10² to 10³ colony-forming units/m³, in all stages of the wastewater treatment plants. The patterns of size distributions of airborne bacteria and fungi were very similar, showing dominant peaks typically in the size range between 3.3 and 4.7 μm. The majority fraction of small bacterial and fungal particles (less than 4.7 μm) in the studied areas indicates that the bioaerosol is relatively fresh, and mostly of local origin. The Gram-positive cocci and nonsporing Gram-positive rods were the dominating forms in the studied wastewater treatment plants environment. The existing differences in the concentration levels between sampling sites enabled identification of the main bioaerosol sources. The highest concentration of bacterial aerosol appeared in sections, where activated sludge post-processing and mechanical purifying are conducted. The most frequently occurring species in the sampled bacterial aerosol were Gram-positive cocci and nonsporing Gram-positive rods. Multi-antibiotic resistance testing showed that among the isolated airborne bacteria, the most antibiotic-resistant features were present among Bacillus species (especially Bacillus mycoides).  相似文献   

The human impact on the transformation of juniper forest landscape in the western part of the Pamir-Alay range (Tajikistan)     

Oimahmad Rahmonov  Tadeusz Szczypek  Tadeusz Niedźwiedź  Urszula Myga-Piątek  Małgorzata Rahmonov  Valerian A. Snytko 《Environmental Earth Sciences》2017,76(8):324

Detailed analyses were conducted of human impact on juniper forest landscapes occurring within the Zarafshan Range (Pamir-Alay). Juniperus seravschanica and J. semiglobosa belong to forest-forming species in Central Asia. At present, juniper forests all over Tajikistan are seriously threatened as a result of excessive logging and cattle grazing. The aim of this paper is to present juniper forest transformation as a result of human activities as well as the diversity of soil properties in the organic and humus horizons in the altitudinal system of soil zonation. Three groups of phytocoenoses were distinguished: those with a dominant share of Juniperus seravschanica; those with a dominant share of J. semiglobosa; and mixed. Associations with Juniperus seravschanica and J. semiglobosa feature several variants of phytocoenoses with dominant species: Artemisia lehmanniana, A. dracunculus, Eremurus olgae, Festuca sulcata, Ligularia thomsonii, Stipa turkestanica, Thymus seravschanicus, and Ziziphora pamiroalaica. The collected soil samples differ in their granulometric composition. Gravelly cobble fractions >2 mm are dominant; the share of sandy particles <2 mm is much lower (about 10–20%). Fraction 0.5–0.05 attains 35% on average. The Corg content of the soil varied from 0.26 to 11.40% in the humus horizon (A) and from 4.3 to 25% in the organic (O). Similar relationships were reported in the case of Ntot concentration. A clear relationship can be observed between concentrations of Corg and Ntot. Soil pH varied, ranging from very low acidic (pH 5.5) to neutral (pH 8.5). The content of available P varied; high concentrations were noted in organic (O) (40.46–211 mg kg^?1) and mixed horizons (OA) (2.61–119 mg kg^?1). Maximum accumulations of Pavail (1739.6 mg kg^?1) and Ptot (9696 mg kg^?1) were observed at a site heavily affected by intense grazing. Concentrations of Mgavail varied from 116 to 964 mg kg^?1. Most of the analysed soil profiles lacked an organic horizon; only thin humus occurred.  相似文献   

Changes in water chemistry along the newly formed High Arctic fluvial–lacustrine system of the Brattegg Valley (SW Spitsbergen,Svalbard)     

Henryk Marszałek  Dorota Górniak 《Environmental Earth Sciences》2017,76(13):449

Changes in water chemistry along the High Arctic fluvial–lacustrine system located in Wedel Jarlsberg Land in the SW Spitsbergen (Svalbard) were investigated during the summer season of 2010 and 2011. The newly formed river–lake system consists of three lakes connected with the Brattegg River. The first bathymetric measurements of these lakes were made by the authors in 2010. The Brattegg River catchment represents a partly glaciered Arctic water system. The studied lakes are characterized by low mineralization and temperature of water. The value of the electrolytic conductivity (EC) ranges from 30.2 to 50.5 μS cm^?1 and the temperature of surface water from 1.5 to 7.8 °C. The temperature increase takes place downstream starting from Upper Lake to the outflow from Myrktjørna Lake. The waters of lakes have higher temperatures than the stream. The predominant ions are HCO₃ ^? (up to 16.5 mg L^?1), Cl^? (6.66–8.53 mg L^?1), Ca²⁺ (2.40–4.45 mg L^?1) and Na⁺ (2.65–3.36 mg L^?1). The highest values of ammonium and DOC found in the lowest Myrktjørna Lake seem to be related to the presence of aquatic organisms and also birds. From the group of 10 analyzed microelements, increased concentrations of aluminum, up to almost 500 μg L^?1, are present in the lakes’ water. Water isotopic composition ranges for δ¹⁸O and δ²H, from ?10.6 to ?10.9‰ and from ?70.8 to ?72.3‰, respectively. The vertical zonality of lake waters is manifested in a decrease in the temperature and increase in EC and chemical elements concentrations.  相似文献   

New results on ground deformation in the Upper Silesian Coal Basin (southern Poland) obtained during the DORIS Project (EU-FP 7)     

Marek Graniczny  Davide Colombo  Zbigniew Kowalski  Maria Przyłucka  Albin Zdanowski 《Pure and Applied Geophysics》2015,172(11):3029-3042

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The degree of urbanization across the globe is not reflected in the δN of seagrass leaves     

Bart Christiaen  Rebecca J. Bernard  Behzad Mortazavi  Just Cebrian  Alice C. Ortmann 《Marine pollution bulletin》2014

Many studies show that seagrass δ¹⁵N ratios increase with the amount of urbanization in coastal watersheds. However, there is little information on the relationship between urbanization and seagrass δ¹⁵N ratios on a global scale. We performed a meta-analysis on seagrass samples from 79 independent locations to test if seagrass δ¹⁵N ratios correlate with patterns of population density and fertilizer use within a radius of 10–200 km around the sample locations. Our results show that seagrass δ¹⁵N ratios are more influenced by intergeneric and latitudinal differences than the degree of urbanization or the amount of fertilizer used in nearby watersheds. The positive correlation between seagrass δ¹⁵N ratios and latitude hints at an underlying pattern in discrimination or a latitudinal gradient in the ¹⁵N isotopic signature of nitrogen assimilated by the plants. The actual mechanisms responsible for the correlation between δ¹⁵N and latitude remain unknown.  相似文献   

Semiannual and annual oscillations of sea level and their impact on asymmetry between El Niño and La Niña episodes     

Małgorzata Świerczyńska  Tomasz Niedzielski  Wiesław Kosek 《Studia Geophysica et Geodaetica》2014,58(2):302-325

The purpose of this paper is twofold. First, we demonstrate that the asymmetry between El Niño and La Niña events recorded in sea level variation occurs only during extreme episodes of El Niño/Southern Oscillation. Second, we explain that the asymmetry is controlled by certain regular cycles which have time-variable amplitudes. Gridded maps of sea level anomaly that form a spatial-temporal time series (spatial resolution: 1° × 1°, sampling interval: 1 week) spanning the time interval from 14/10/1993 to 18/04/2012 were used. We examined those time series and found that certain regular harmonic signals (periods: 365, 182, 120, 90 and 62 days) are dominant terms of their temporal variability. By subtracting those oscillations from sea level anomaly data, residuals were determined. Using skewness and kurtosis as measures of asymmetry and nonlinearity — after adopting 10-year moving window — we found that the extreme El Niño 1997/1998 has been a dominant driving force of the asymmetry and nonlinearity of El Niño/Southern Oscillation since the end of 1993. In order to detect residual signals that are responsible for the asymmetry, we applied the Fourier Transform Band Pass Filter and found that there are two important oscillations remaining in the residual sea level anomaly data, i.e. the annual and semiannual ones with time-varying amplitudes. We hypothesize that temporarily uneven amplitudes have meaningful impact on the aforementioned asymmetry.  相似文献