Surface-Parallel Sensor Orientation for Assessing Energy Balance Components on Mountain Slopes     

P. Serrano-Ortiz  E. P. Sánchez-Cañete  F. J. Olmo  S. Metzger  O. Pérez-Priego  A. Carrara  L. Alados-Arboledas  A. S. Kowalski 《Boundary-Layer Meteorology》2016,158(3):489-499

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An efficient PBL model for global circulation models-design and validation     

H. P. Zinn  A. D. Kowalski 《Boundary-Layer Meteorology》1995,75(1-2):25-59

An efficient, pianetary boundary layer (PBL) model is developed and validated with empirical data for applications in general circulation models (GCMs). The purpose of this PBL model is to establish the turbulent surface fluxes as a function of the principal external PBL parameters in a numerically efficient way. It consists of a surface layer and a mixed layer matched together with the conditions of constant momentum and heat flux at the interface. An algebraic solution to the mean momentum equations describes the mixed-layer velocity profile and thus determines the surface wind vector. The velocity profile is globally valid by incorporating the effect of variable Coriolis force without becoming singular at the equator. Turbulent diffusion depends on atmospheric stability and is modeled in the surface layer by a drag law and with first-order closure in the mixed layer. Radiative cooling in the stably stratified PBL is considered in a simple manner. The coupled system is solved by an iterative method. In order to preserve the computational efficiency of the large-scale model, the PBL model is implemented into the GISS GCM by means of look-up tables with the bulk PBL Richardson number, PBL depth, neutral drag coefficient, and latitude as independent variables.A validation of the PBL model with observed data in the form of Rossby number similarity theory shows that the internal feedback mechanisms are represented correctly. The model, however, underpredicted the sensible heat-flux. A subsequent correction in the turbulence parameterization yields better agreement with the empirical data. The behavior of the principal internal PBL quantities is presented for a range of thermal stabilities and latitudes.  相似文献   

Modified logarithmic tachoida applied to sediment transport in a river     

Zygmunt Meyer 《Acta Geophysica》2009,57(3):743-759

In this paper, a modified tachoida is applied to the estimation of sediment transport in a river. Eddy viscosity coefficient at the bottom which satisfied hydrodynamics stability of the flow is related to the sediment concentration. On this basis it was possible to determine the sediment stream in the river based on the bottom sediment composition.  相似文献   

Evaluation of Pollution Degree of the Odra River Basin with Organic Compounds after the 1997 Summer Flood – General Comments     

L. Wolska  W. Wardencki  M. Wiergowski  B. Zygmunt  B. Zabiega&#x;a  P. Konieczka  L. Poprawski  J. F. Biernat  J. Namienik 《洁净——土壤、空气、水》1999,27(5):343-349

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The application of two‐dimensional hydrodynamic models for underwater archaeological finds from the Vistula River in Warsaw,Poland          下载免费PDF全文

Hubert Kowalski  Artur Magnuszewski  Artur Radecki‐Pawlik 《水文研究》2018,32(18):2888-2900

Low water levels occurring on the Warsaw section of the Vistula River during droughts in 2012 and 2015 stirred considerable interest by exposing parts of the riverbed. The river's low flow discharge created favourable conditions for archaeologists who, from the river's bottom, managed to salvage sculptures, architectural artefacts, and military accessories dating back to the middle of the 17th century. Literature shows that archaeological finds at the bottom of a major lowland river are unique and are attributed to very specific hydrological and geological conditions. Embankments and works meant to regulate the channel of the Vistula River in Warsaw narrowed the channel and accelerated the erosion of the river's bottom. A comparison of rating curves created between 1919 and 2015 shows that the river's bottom had lowered by 225 cm. The diameter of sediment particles that could be moved at maximum shear stress has been calculated using the Meyer–Peter and Muller formula. According to the calculated shear stress corresponding to the highest historical flood of 1844 particles smaller than 0.05 m were transported down the river, and it is true that artefacts of that size had not been collected at the site. Taking into consideration the very specific geological and hydrological conditions, we believe that finding so many 17th century artefacts with a well‐documented history at a site at the bottom of major lowland river with intensive channel processes is indeed unique. Additionally, it is the first time that results of hydrodynamic modelling have been successfully used for archaeological survey to define the critical shear stress and the smallest diameter of artefacts, which could remain stable on a river's bottom.  相似文献   

The Characteristics of Solar X-Class Flares and CMEs: A Paradigm for Stellar Superflares and Eruptions?     

Louise K. Harra  Carolus J. Schrijver  Miho Janvier  Shin Toriumi  Hugh Hudson  Sarah Matthews  Magnus M. Woods  Hirohisa Hara  Manuel Guedel  Adam Kowalski  Rachel Osten  Kanya Kusano  Theresa Lueftinger 《Solar physics》2016,291(6):1761-1782

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Carbon and water exchange in semiarid ecosystems in SE Spain     

F. Domingo  P. Serrano-Ortiz  A. Were  L. Villagarcía  M. García  D.A. Ramírez  A.S. Kowalski  M.J. Moro  A. Rey  C. Oyonarte 《Journal of Arid Environments》2011,75(12):1271-1281

The changing climate is affecting biological and physical processes occurring in the biosphere, including the biogeochemical cycles of water and carbon. The response of ecosystem carbon exchange to changes in temperature and the water balance is still very uncertain, a fact that highlights the need for research in order to understand the role of the biosphere in the future global carbon budget. South east Spain is on the borderline between the tropical and mid-latitude climate zones, with climates ranging from sub-humid to arid, and the majority representing the driest area in Europe. Initial predictions on climate change for this region point to decreases in total precipitation and the number of precipitation events, meaning a decrease in water availability underlining the vulnerability of the region to desertification. This region, due to these special climatic conditions, has been the subject of experimental carbon and water field research in recent years. This paper defines the state of the art of carbon and water balance measurement and modelling studies in this region, analyses the different processes involved in aggregate exchanges (vegetation and soil; net ecosystem carbon balance–evapotranspiration, photosynthesis–transpiration, soil respiration–evaporation), and identifies needs for future research.  相似文献   

Mercury mobility and bioavailability in soil from contaminated area   总被引：2，自引：0，他引：2  

Leonard Boszke  Artur Kowalski  Aleksander Astel  Andrzej Barański  Barbara Gworek  Jerzy Siepak 《Environmental Geology》2008,55(5):1075-1087

The mobility and bioavailability of mercury in the soil from the area near a plant using elemental mercury for manufacturing thermometers, areometers, glass energy switches and other articles made of technical glass has been evaluated. Mercury has been determined by sequential extraction method and with additional thermo desorption stage to determine elemental mercury. The procedure of sequential extraction involves five subsequent stages performed with the solutions of chloroform, deionized water, 0.5 M HCl, 0.2 M NaOH and aqua regia. The mean concentration of total mercury in soil was 147 ± 107 μg g⁻¹ dry mass (range 62–393), and the fractionation revealed that mercury was mainly bound to sulfides 56 ± 8% (range 45–66), one of the most biounavailable and immobile species of mercury in the environment. The fractions that brought lower contribution to the total mercury content were semi-mobile humic matter 22 ± 9% (range 11–34) and elemental mercury 17 ± 5% (range 8–23). The contributions brought by the highly mobile and toxic organomercury compounds were still lower 2.3 ± 2.7% (range 0.01–6.5). The lowest contributions brought the acid-soluble mercury 1.5 ± 1.3% (range 0.1–3.5) and water-soluble mercury 1.0 ± 0.3% (range 0.6–1.7). The surface layer of soil (0–20 cm) was characterized by higher mercury concentrations than that of the subsurface soil (60–80 cm), but the fractional contributions were comparable. The comparison of mercury fractionation results obtained in this study for highly polluted soils with results of fractionation of uncontaminated or moderately contaminated samples of soil and sediments had not shown significant statistical differences; however, in the last samples elemental mercury is usually present at very low concentrations. On the basis of obtained correlation coefficients it seems that elemental mercury soils from “Areometer” plant are contaminated; the main transformation is its vaporization to atmosphere and oxidation to divalent mercury, probably mainly mediated by organic matter, and next bound to humic matter and sulfides.  相似文献   

Use of the temperature–vegetation dryness index for remote sensing grassland moisture conditions in the vicinity of a lignite open-cast mine     

Karol Przeździecki  Jarosław Zawadzki  Zygmunt Miatkowski 《Environmental Earth Sciences》2018,77(17):623

Anthropogenic activities, especially resulting in changes in the water conditions, usually disturb biological and agricultural functions of grasslands, leading to their degradation, often on large areas. Remote sensing observations of such changes in grassland ecosystems evoke a great interest, but they are still a difficult task, especially when performed on industrial and mining areas. This paper presents a new effective method of remote sensing of grassland moisture conditions based on temperature–vegetation dryness index (TVDI) calculated from free Landsat imagery, and employing the TVDI spatial variability estimated from a semivariance analysis. The practical applicability of the method is demonstrated on the example of monitoring of the extensive neighborhood of lignite open-cast mine within a period of a few years. Besides, the developed method was validated at the studied area, using in situ information. Thus, we demonstrated that TVDI may serve as an effective indicator of grassland moisture conditions, even in problematic areas.  相似文献   

Wave Dispersion Study in the Indian Ocean-Tsunami of December 26, 2004     

Juan Horrillo  Zygmunt Kowalik  Yoshinori Shigihara 《Marine Geodesy》2013,36(3):149-166

A numerical study which takes into account wave dispersion effects has been carried out in the Indian Ocean to reproduce the initial stage of wave propagation of the tsunami event that occurred on December 26, 2004. Three different numerical models have been used: the nonlinear shallow water (nondispersive), the nonlinear Boussinesq, and the full Navier-Stokes aided by the volume of fluid method to track the free surface. Numerical model results are compared against each other. General features of the wave propagation agreed very well in all numerical studies. However some important differences are observed in the wave patterns, i.e., the development in time of the wave front is shown to be strongly connected to the dispersion effects. Discussions and conclusions are made about the spatial and temporal distribution of the free surface reaffirming that the dispersion mechanism is important for tsunami hazard mitigation.  相似文献