Study of vertical structure of aerosol optical properties with sun photometers and ceilometer during the MACRON campaign in 2007     

Krzysztof M. Markowicz  Tymon Zieliński  Sandra Blindheim  Michael Gausa  Anna K. Jagodnicka  Aleksandra E. Kardas  Wojciech Kumala  Szymon P. Malinowski  Tomasz Petelski  Michał Posyniak  Tadeusz Stacewicz 《Acta Geophysica》2012,60(5):1308-1337

This paper presents the measurements of a vertical structure of aerosol optical properties performed during the MACRON (Maritime Aerosol, Clouds and Radiation Observation in Norway) campaign, which took place in July and August 2007 at ALOMAR observatory on Andøya island (69.279°N, 16.009°E, elevation 380 m a.s.l.). The mean value of the aerosol optical thickness (AOT) at 500 nm during campaign was 0.12. Significant increase of the AOT above longtime mean value was observed on 7 and 8 August 2007 when the AOT exceeded 0.4 at 500 nm. Analyses of back trajectories show the aerosol transported from over Africa and Central Europe. The aerosol extinction coefficient obtained from the synergy of ceilometer and sun photometer observations reached 0.05–0.08 km^?1 (at 1064 nm) in the dust layer. The single scattering albedo at the ALOMAR observatory decreased during the dust episode to 0.93–0.94, which indicates some absorptive aerosols in the lower PBL.  相似文献   

Semi-Empirical Oceanic Depth–Age Relationship Inferred from Bathymetric Curve     

Tomasz Niedzielski  Mirosława Jurecka  Piotr Migoń 《Pure and Applied Geophysics》2016,173(5):1829-1840

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Use of Remotely-Derived Bathymetry for Modelling Biomass in Marine Environments     

Małgorzata M. Wieczorek  Waldemar A. Spallek  Tomasz Niedzielski  Jasmin A. Godbold  Imants G. Priede 《Pure and Applied Geophysics》2014,171(6):1029-1045

The paper presents results on the influence of geometric attributes of satellite-derived raster bathymetric data, namely the General Bathymetric Charts of the Oceans, on spatial statistical modelling of marine biomass. In the initial experiment, both the resolution and projection of the raster dataset are taken into account. It was found that, independently of the equal-area projection chosen for the analysis, the calculated areas are very similar, and the differences between them are insignificant. Likewise, any variation in the raster resolution did not change the computed area. Although the differences were shown to be insignificant, for the subsequent analysis we selected the cylindrical equal area projection, as it implies rectangular spatial extent, along with the automatically derived resolution. Then, in the second experiment, we focused on demersal fish biomass data acquired from trawl samples taken from the western parts of ICES Sub-area VII, near the sea floor. The aforementioned investigation into processing bathymetric data allowed us to build various statistical models that account for a relationship between biomass, sea floor topography and geographic location. We fitted a set of generalised additive models and generalised additive mixed models to combinations of trawl data of the roundnose grenadier (Coryphaenoides rupestris) and bathymetry. Using standard statistical techniques—such as analysis of variance, Akaike information criterion, root mean squared error, mean absolute error and cross-validation—we compared the performance of the models and found that depth and latitude may serve as statistically significant explanatory variables for biomass of roundnose grenadier in the study area. However, the results should be interpreted with caution as sampling locations may have an impact on the biomass–depth relationship.  相似文献   

Scenarios of water resources development in Poland up to 2030     

Tomasz Walczykiewicz 《Water Resources》2014,41(6):763-773

Due to the fact that water management responds to changing natural and socio-economic conditions its future perspective, depending on multiple and variable factors, is difficult to predict using traditional prognostic methods. The examined hypothesis shows that the scenario development process is a useful method for long-term strategic planning in the water management sector. Research was completed on the basis of expert assessments and panel discussions and structured as a scenario for the development process. The IPCC Emission Scenarios constitute the future development context. The results show that this predictive method is effective. Sensitivity of the results of the applied techniques of development scenarios shows a need for further research.  相似文献   

Feedback mechanisms in chemo-mechanical multi-scale modeling of soil and sediment compaction     

Tomasz Hueckel  Liang Bo Hu 《Computers and Geotechnics》2009

Geomaterials respond to some environmental circumstances through generation of a series of feedback mechanisms of damage, deformation, erosion, and chemical processes or reactions: e.g. osmosis, dissolution and precipitation, mineral transformations. These mechanisms are coupled at different scales. Several natural geomechanical processes, as sediment compaction, rock weathering or landsliding appear to include such sequences of mechanisms. A multi-physics model of sediment compaction is examined from the point of view of feedbacks and feedforwards for the phenomena involved at micro- and meso-scale. Two types of feedback are identified: constitutive feedbacks and boundary condition feedbacks. A numerical sensitivity study points out which feedbacks and feedforwards are strong and which are weak.  相似文献   

Small angle X-ray scattering mapping and kinetics study of sub-critical CO2 sorption by two Australian coals     

Andrzej P. Radliński  Tara L. Busbridge  Evan Mac A. Gray  Tomasz P. Blach  David J. Cookson 《International Journal of Coal Geology》2009,77(1-2):80-89

Time- and position-resolved synchrotron small angle X-ray scattering data were acquired from samples of two Australian coal seams: Bulli seam (Bulli 4, R_o = 1.42%, Sydney Basin), which naturally contains CO₂ and Baralaba seam (R_o = 0.67%, Bowen Basin), a potential candidate for sequestering CO₂. This experimental approach has provided unique, pore-size-specific insights into the kinetics of CO₂ sorption in the micro- and small mesopores (diameter 5 to 175 Å) and the density of the sorbed CO₂ at reservoir-like conditions of temperature and hydrostatic pressure.For both samples, at pressures above 5 bar, the density of CO₂ confined in pores was found to be uniform, with no densification in near-wall regions. In the Bulli 4 sample, CO₂ first flooded the slit pores between polyaromatic sheets. In the pore-size range analysed, the confined CO₂ density was close to that of the free CO₂. The kinetics data are too noisy for reliable quantitative analysis, but qualitatively indicate faster kinetics in mineral-matter-rich regions.In the Baralaba sample, CO₂ preferentially invaded the smallest micropores and the confined CO₂ density was up to five times that of the free CO₂. Faster CO₂ sorption kinetics was found to be correlated with higher mineral matter content but, the mineral-matter-rich regions had lower-density CO₂ confined in their pores. Remarkably, the kinetics was pore-size dependent, being faster for smaller pores.These results suggest that injection into the permeable section of an interbedded coal-clastic sequence could provide a viable combination of reasonable injectivity and high sorption capacity.  相似文献   

Can we trust climate models to realistically represent severe European windstorms?     

Tomasz M. Trzeciak  Peter Knippertz  Jennifer S. R. Pirret  Keith D. Williams 《Climate Dynamics》2016,46(11-12):3431-3451

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Changes in PM<Subscript>10</Subscript> concentration due to large-scale rainfall     

Tomasz?OlszowskiEmail authorView author&#;s OrcID profile 《Arabian Journal of Geosciences》2016,9(2):160

This paper is concerned with the estimation of the removal efficiency of PM₁₀ by large-scale precipitation under no-wind conditions in a background (rural) and urban areas. The changes in PM₁₀ concentrations before, during and after the presence of rainfall were studied from 2007 to 2013. The study was conducted in two different locations identified with regard to air quality. DAVIS weather stations were used to determine the meteorological conditions. The concentration of PM₁₀ was calculated with the use of the gravimetric reference method. Two hundred and ninety-nine measurement series were carried out. A linear relationship was found between the intensity and duration of rainfall and the value of the removal coefficient (ΔC). It was proved that except light rains, for the near-to-ground troposphere, the effectiveness of the removal of PM₁₀ (ΔC) did not assume different values at various locations for rainfall with the same intensity and duration. It was found that a temporary interaction of the effect of the purification by wet deposition was being minimised in areas characterised by low air quality. It was confirmed that intense rains resulted in the maintenance of higher values of air quality.  相似文献   

Desiccation shrinkage of non‐clayey soils: a numerical study     

Liang Bo Hu  Hervé Péron  Tomasz Hueckel  Lyesse Laloui 《国际地质力学数值与分析法杂志》2013,37(12):1782-1800

A mesoscale model of desiccation of soil based on the evolution of the pore system idealized as bimodal is numerically examined. A simplified evolution of the model reveals a series of characteristics that qualitatively agree with the observed macroscopic experimental findings. The principal mechanism is deemed to be driven by the surface evaporation and water outflow generating a pore pressure gradient resulting in the shrinkage mainly of the largest pores. The amount of shrinkage is a function of (negative) pore pressure and is controlled by the compressibility of the solid matrix. The numerical model includes also the ensuing partial saturation stage initiated by the air entry simulated as a scenario with a moving phase interface inside the pore. The proposed model can be extended beyond the two‐mode porosity soils, to include the multi‐modal porosity, or its statistical representation.Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Climate change during the past 1000 years: a high‐temporal‐resolution multiproxy record from a mire in northern Finland     

Walter Finsinger  Kristian Schoning  Sheila Hicks  Andreas Lücke  Tomasz Goslar  Friederike Wagner‐cremer  Heidi Hyyppä 《第四纪科学杂志》2013,28(2):152-164

We present a record of peatland development in relation to climate changes and human activities from the Palomaa mire, a remote site in northern Finland. We used fine‐resolution and continuous sampling to analyse several proxies including pollen (for vegetation on and around the mire), testate amoebae (TA; for mire‐wetness changes), oxygen and carbon isotopes from Sphagnum cellulose (δ¹⁸O and δ¹³C; for humidity and temperature changes), peat‐accumulation rates and peat‐colour changes. In spite of an excellent accumulation model (30 ¹⁴C dates and estimated standard deviation of sample ages <1 year in the most recent part), the potential to determine cause–effect (or lead–lag) relationships between environmental changes and biotic responses is limited by proxy‐specific incorporation processes below the actively growing Sphagnum surface. Nevertheless, what emerges is that mire development was closely related to water‐table changes rather than to summer temperature and that water‐table decreases were associated with increasing peat‐accumulation rates and more abundant mire vegetation. A rapid fen‐to‐bog transition occurred within a few years around AD 1960 when the water table decreased beyond the historical minimum, supporting the notion that mires can rapidly shift into bogs in response to allogenic factors. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献