Composite surface temperature history from simultaneous inversion of borehole temperatures in western Canadian plains     

Jacek A. Majorowicz  Jan Safanda 《Global and Planetary Change》2001,29(3-4)

Functional space inversions (FSI) of precise temperature logs from wells located in low conductivity clastic sediments of the western Canadian Sedimentary Basin show evidence of extensive, recent ground surface temperature (GST) warming. Simultaneous inversion of the data, as well as averaging of the individual site reconstructions, indicate that this high magnitude of GST warming exceeds over two times that of globally averaged GST's [Science 282 (1998) 279] and is significantly higher than that of surface temperature histories based on instrumental records and tree ring reconstruction in northern and western Canada [Holocene 7 (1997) 375; Science 278 (1997) 1251; Clim. Res. 12 (1999) 39].  相似文献   

Luminosity function for galaxies and cosmology     

Krzysztof D. Maślanka 《Astrophysics and Space Science》1984,100(1-2):407-411

Formulae for two classical cosmological tests,N(z) andN(m) are obtained with the luminosity function taken into account. From the testN(m) and Jarvis and Tyson observational data, characteristic absolute magnitude of galaxiesM ^*=–20.05 and mean extragalactic absorptionA=4×10^–4 mag Mpc^–1 have been found.  相似文献   

M-estimation with probabilistic models of geodetic observations   总被引：1，自引：1，他引：0  

Z. Wiśniewski 《Journal of Geodesy》2014,88(10):941-957

The paper concerns \(M\) -estimation with probabilistic models of geodetic observations that is called \(M_{\mathcal {P}}\) estimation. The special attention is paid to \(M_{\mathcal {P}}\) estimation that includes the asymmetry and the excess kurtosis, which are basic anomalies of empiric distributions of errors of geodetic or astrometric observations (in comparison to the Gaussian errors). It is assumed that the influence function of \(M_{\mathcal {P}}\) estimation is equal to the differential equation that defines the system of the Pearson distributions. The central moments \(\mu _{k},\, k=2,3,4\) , are the parameters of that system and thus, they are also the parameters of the chosen influence function. The \(M_{\mathcal {P}}\) estimation that includes the Pearson type IV and VII distributions ( \(M_{\mathrm{PD(l)}}\) method) is analyzed in great detail from a theoretical point of view as well as by applying numerical tests. The chosen distributions are leptokurtic with asymmetry which refers to the general characteristic of empirical distributions. Considering \(M\) -estimation with probabilistic models, the Gram–Charlier series are also applied to approximate the models in question ( \(M_{\mathrm{G-C}}\) method). The paper shows that \(M_{\mathcal {P}}\) estimation with the application of probabilistic models belongs to the class of robust estimations; \(M_{\mathrm{PD(l)}}\) method is especially effective in that case. It is suggested that even in the absence of significant anomalies the method in question should be regarded as robust against gross errors while its robustness is controlled by the pseudo-kurtosis.  相似文献   

Homogeneous reprocessing of GPS,GLONASS and SLR observations   总被引：3，自引：2，他引：1  

Mathias Fritsche  Krzysztof Sośnica  Carlos Javier Rodríguez-Solano  Peter Steigenberger  Kan Wang  Reinhard Dietrich  Rolf Dach  Urs Hugentobler  Markus Rothacher 《Journal of Geodesy》2014,88(7):625-642

The International GNSS Service (IGS) provides operational products for the GPS and GLONASS constellation. Homogeneously processed time series of parameters from the IGS are only available for GPS. Reprocessed GLONASS series are provided only by individual Analysis Centers (i. e. CODE and ESA), making it difficult to fully include the GLONASS system into a rigorous GNSS analysis. In view of the increasing number of active GLONASS satellites and a steadily growing number of GPS+GLONASS-tracking stations available over the past few years, Technische Universität Dresden, Technische Universität München, Universität Bern and Eidgenössische Technische Hochschule Zürich performed a combined reprocessing of GPS and GLONASS observations. Also, SLR observations to GPS and GLONASS are included in this reprocessing effort. Here, we show only SLR results from a GNSS orbit validation. In total, 18 years of data (1994–2011) have been processed from altogether 340 GNSS and 70 SLR stations. The use of GLONASS observations in addition to GPS has no impact on the estimated linear terrestrial reference frame parameters. However, daily station positions show an RMS reduction of 0.3 mm on average for the height component when additional GLONASS observations can be used for the time series determination. Analyzing satellite orbit overlaps, the rigorous combination of GPS and GLONASS neither improves nor degrades the GPS orbit precision. For GLONASS, however, the quality of the microwave-derived GLONASS orbits improves due to the combination. These findings are confirmed using independent SLR observations for a GNSS orbit validation. In comparison to previous studies, mean SLR biases for satellites GPS-35 and GPS-36 could be reduced in magnitude from \(-35\) and \(-38\)  mm to \(-12\) and \(-13\)  mm, respectively. Our results show that remaining SLR biases depend on the satellite type and the use of coated or uncoated retro-reflectors. For Earth rotation parameters, the increasing number of GLONASS satellites and tracking stations over the past few years leads to differences between GPS-only and GPS+GLONASS combined solutions which are most pronounced in the pole rate estimates with maximum 0.2 mas/day in magnitude. At the same time, the difference between GLONASS-only and combined solutions decreases. Derived GNSS orbits are used to estimate combined GPS+GLONASS satellite clocks, with first results presented in this paper. Phase observation residuals from a precise point positioning are at the level of 2 mm and particularly reveal poorly modeled yaw maneuver periods.  相似文献   

Long-Term Ozone Changes Over the Northern Hemisphere Mid-Latitudes for the 1979–2012 Period     

Janusz W. Krzyścin  Bonawentura Rajewska-Więch  Izabela Pawlak 《大气与海洋》2015,53(1):153-160

Abstract

The solar backscattered ultraviolet (SBUV/SBUV-2) merged ozone datasets, version 8.6, including column ozone and ozone profiles for the 1979–2012 period are examined for the 35°N–60°N zonal belt in the northern hemisphere mid-latitudes and four sub-regions: central Europe, continental Europe, North America, and East Asia. The residual long-term patterns for total ozone and ozone profiles are extracted by smoothing the time series of differences between the original and the modelled ozone time series. Modelled ozone is obtained using the standard trend model accounting for ozone variability due to changes in stratospheric halogens and various dynamical factors commonly used in previous ozone trend analyses. Since about 2005 spring and summer total ozone in the troposphere and lower stratosphere has decreased in some regions (central and continental Europe, North America, and the 35°N–60°N zonal belt) compared with modelled ozone. The negative departure from modelled ozone in 2010 is approximately 2–3% of the overall 1979–2012 monthly mean level. It seems that this decrease is a result of yet unknown dynamical processes rather than to chemical destruction because the differences have a longitudinal structure, and total ozone in the upper stratosphere still follows changes in stratospheric halogen loading.  相似文献   

The Little Ice Age signature and subsequent warming seen in borehole temperature logs versus solar forcing model     

Jacek Majorowicz  Jan Šafanda  Rajmund Przybylak 《International Journal of Earth Sciences》2014,103(4):1163-1173

The ‘low’ in the transient temperature versus depth borehole profiles around 120 m seen from deep temperature logs in the Canadian Prairies (southern Alberta–southern Saskatchewan), as well as in some of the European data, has been interpreted to be related to the Little Ice Age (LIA). Data point to the lowest ground surface and subsurface temperatures occurring in the very late eighteenth to nineteenth centuries. Inversion of these logs shows that surface temperature lows were followed by a recent warming period. Further, the synthetic profiles built on the basis of solar forcing history, stretching as far back as the beginning of the seventeenth century, suggest that the LIA signatures interpreted from the inversion of the borehole temperature logs would be difficult to be explained by known published models of past solar irradiation despite large range of assumed sensitivities for the couplings assumed, and that further forcing needs to be considered.  相似文献   

An integrative geothermal resource assessment study for the siliciclastic Granite Wash Unit,northwestern Alberta (Canada)     

Simon N. Weides  Inga S. Moeck  Douglas R. Schmitt  Jacek A. Majorowicz 《Environmental Earth Sciences》2014,72(10):4141-4154

This study explores the siliciclastic Granite Wash Unit in northwestern Alberta as a potential geothermal reservoir. The approach covers regional 3D structural geological modelling of a 90 km × 70 km area based on well log and legacy 2D seismic data. The fault strike was interpreted from lineaments, which were identified with the refined trend surface analysis method. The stress state of the Granite Wash reservoirs was determined by an integrated approach of 3D fault modelling, stress ratio definition based on frictional constraints, and slip tendency analysis. The results show that the best site for a geothermal application is located in the southwestern study area, where the highest temperatures (above 70 °C) coincide with the largest thickness (above 20 m) and zones of elevated porosity and permeability. The integrated stress analysis indicates an in situ stress regime from normal to strike-slip faulting maintaining a non-critically stressed reservoir or faults therein, assuming a friction coefficient of 0.7. The granite wash reservoirs could be used for heating of greenhouses, domestic warm water provision and district heating.  相似文献   

Mycobiota of the disused ore mine of Marcinków in?nie?nik Masiff(western Poland)     

Wojciech Pusz  Anna Baturo-Cieśniewska  Paweł Zagożdżon  Rafał Ogórek 《山地科学学报》2017,14(12):2448-2457

Marcinków(Lower Silesia, ?nie?nik Masiff,south-western Poland) has been a well-known mining centre since the mid-15 th century. Mineral extraction ended in 1949 with the ores of Pb, Ag, Cu and occasionally Au, U or graphite mined there. The mine is surrounded by metamorphic graphite and mica schist. It is not open to the public and no bats have been recorded living in. The aim of this study was the mycological analysis of the air, the rock surface and the water of the disused ore mine of Marcinków.Additionally, the chemical composition of rocks and water, and microclimate conditions of the adit were determined. Fungi were identified using a combination of phenotypic and molecular methods.Six taxa of fungi were cultured from the indoor air samples of the adit, whereas the outdoor air samples contained only five taxa. On the other hand, nine taxa were isolated from both the rocky walls and the water.The Aspergillus group was present only on the rocks and in the water, whereas Cladosporium herbarum,Dumontinia tuberosa, Epicoccum nigrum, Hirsutella sp., were found exclusively in the air. The mycobiota found in the ore mine were mostly similar to those recorded in other mines and natural caves. However,it should be noted that the internal microclimate and chemical compounds of the rocks.  相似文献   

Modelling hydraulic and capillary-driven two-phase fluid flow in unsaturated concretes at the meso-scale with a unique coupled DEM-CFD technique     

Marek Krzaczek  Michał Nitka  Jacek Tejchman 《国际地质力学数值与分析法杂志》2023,47(1):23-53

The goal of the research was to demonstrate the impact of thin porous interfacial transition zones (ITZs) between aggregates and cement matrix on fluid flow in unsaturated concrete caused by hydraulic/capillary pressure. To demonstrate this impact, a novel coupled approach to simulate the two-phase (water and moist air) flow of hydraulically and capillary-driven fluid in unsaturated concrete was developed. By merging the discrete element method (DEM) with computational fluid dynamics (CFD) under isothermal settings, the process was numerically studied at the meso-scale in two-dimensional conditions. A flow network was used to describe fluid behaviour in a continuous domain between particles. Small concrete specimens of a simplified particle mesostructure were subjected to fully coupled hydro-mechanical simulation tests. A simple uniaxial compression test was used to calibrate the pure DEM represented by bonded spheres, while a permeability and sorptivity test for an assembly of spheres was used to calibrate the pure CFD. For simplified specimens of the pure cement matrix, cement matrix with aggregate, and cement matrix with aggregate and ITZ of a given thickness, DEM/CFD simulations were performed sequentially. The numerical results of permeability and sorptivity were directly compared to the data found in the literature. A satisfactory agreement was achieved. Porous ITZs in concrete were found to reduce sorption by slowing the capillary-driven fluid flow, and to speed the full saturation of pores when sufficiently high hydraulic water pressures were dominant.  相似文献