Broad-band X-ray/γ-ray spectra and binary parameters of GX 339–4 and their astrophysical implications     

Andrzej A. Zdziarski  Juri Poutanen  Joanna Mikolajewska  Marek Gierli&#;ski  Ken Ebisawa  & W. Neil Johnson 《Monthly notices of the Royal Astronomical Society》1998,301(2):435-450

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Vertical velocities in Finland from permanent GPS networks and from repeated precise levelling     

J. Mkinen  H. Koivula  M. Poutanen  V. Saaranen 《Journal of Geodynamics》2003,35(4-5):443-456

Postglacial rebound is a long-studied phenomenon in Fennoscandia, and the general features of contemporary vertical motion (0–8 mm/year relative to mean sea level) are well known from tide gauges and repeated precise levelling. GPS on permanent stations has proved to be a powerful tool in studies of crustal motion, capable of detecting small trends in a fraction of the time required by the classical methods. We determine vertical velocities from 5 years of data in the permanent Finnish GPS network FinnRef®. We compare them with velocities derived from three precise levellings spanning nearly hundred years, and from tide gauge records. From the comparison, both FinnRef velocities and levelled velocities appear to be accurate to 0.4 mm/year (one-sigma). The isobases (lines of equal velocities) are less elongated towards northeast than in geophysical models of the rebound. However, the processing of nearly the same GPS data in BIFROST using different methods produces velocities that disagree with FinnRef more than levelling does. The levelled velocities are between the two GPS results and do not resolve the conflict.  相似文献   

Reply   总被引：1，自引：0，他引：1  

Markku Heikkinen 《Journal of Geodesy》1980,54(2):222-223

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A Swedish case study of contemporary and possible future consequences of climate change on lake function   总被引：6，自引：0，他引：6  

Thorsten Blenckner  Anders Omstedt  Markku Rummukainen 《Aquatic Sciences - Research Across Boundaries》2002,64(2):171-184

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Rock, till, and stream-sediment geochemistry in the search for porphyry-type Mo---Cu---Au deposits in the proterozoic rautio batholith, Western Finland     

Pekka A. Nurmi  Markku Isohanni 《Journal of Geochemical Exploration》1984,21(1-3)

About 170 bedrock, 550 till, and 180 organic-rich stream-sediment samples were collected at a regional scale over the Rautio batholith, and 490 rock and 1050 till samples at a local scale from around the Susineva Mo---Cu---Au occurrence which is located in the middle of the batholith. The rock samples from the regional study and selected rock samples from the Susineva area were analyzed for 32 elements. The rest of the rock samples from Susineva and all other sample types were analyzed for Mo and Cu only.  相似文献   

Size-resolved characterisation of organic compounds in atmospheric aerosols collected at Welgegund,South Africa     

Wanda Booyens  Pieter G. Van Zyl  Johan P. Beukes  Jose Ruiz-Jimenez  Matias Kopperi  Marja-Liisa Riekkola  Miroslav Josipovic  Andrew D. Venter  Kerneels Jaars  Lauri Laakso  Ville Vakkari  Markku Kulmala  Jacobus J. Pienaar 《Journal of Atmospheric Chemistry》2015,72(1):43-64

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Geodetic determination of the surface topography of the Baltic Sea     

Juhani Kakkuri  Markku Poutanen 《Marine Geodesy》2013,36(4):307-316

The Baltic Sea Level Project is an international scientific observation program to unify the vertical datums of the countries of the Baltic Sea with GPS measurements. In total, 35 tide gauges on shores and islands of the Baltic were occupied with GPS in 1993. After computing a new gravimetric geoid over the Baltic Sea, it was possible to unify the datums as well as to calculate the orthometric heights and the sea surface topography values for the tide gauge stations. The results obtained are shown.  相似文献   

Climate change: changing means and changing extremes   总被引：1，自引：0，他引：1  

Markku Rummukainen 《Climatic change》2013,121(1):3-13

Ongoing global warming not only involves changes in temperature and the global mean; it affects more or less every part of the climate. Regional temperature changes are often greater or smaller than corresponding changes in the global mean. In some cases the direction of change may also be different. For example, temperature changes are higher over land than over the ocean. Precipitation increases in some regions but decreases in others. Changes in extreme events may differ from changes in the corresponding mean. Present scientific knowledge clearly indicates that the already observed global trend towards warmer conditions will continue and that it will be accompanied by changes in yet other aspects of climate. This paper highlights, as a brief review, aspects of our changing climate from the available scientific knowledge with a bearing on the energy sector. Its focus is on temperature and precipitation, with some consideration of wind and sea level, among others. While uncertainties remain as far as the magnitude of future global-scale changes is concerned, and even more so their many regional patterns, significant changes are foreseen in, for example, global and regional temperature and precipitation, sea level rise, and in the characteristics of various extreme events.  相似文献   

Origin of ultra-nickeliferous olivine in the Kevitsa Ni–Cu–PGE-mineralized intrusion, northern Finland     

Sheng-Hong Yang  Wolfgang D. Maier  Eero J. Hanski  Markku Lappalainen  Frank Santaguida  Sanna Määttä 《Contributions to Mineralogy and Petrology》2013,166(1):81-95

The 2,058 ± 4 Ma mafic–ultramafic Kevitsa intrusion is located in the Central Lapland greenstone belt, northern Finland. It is hosted by a Paleoproterozoic volcano–sedimentary sequence that contains komatiitic volcanic rocks and sulfide- and graphite-rich black schists. Economic Ni–Cu–(PGE) sulfide mineralization occurs in the middle part of the ultramafic lower unit of the intrusion. Two main types of ore are distinguished, “normal” and “Ni–PGE” ores. The normal ore is characterized by ~2 to 6 vol% disseminated sulfides and average Ni and Cu grades of 0.3 and 0.42 wt %, respectively (Ni/Cu < 1). The Ni–PGE ore has broadly similar sulfide contents, but a higher Ni grade and lower Cu grade. As a result, the Ni/Cu ratio reaches 15, much higher than in the normal ore. The Ni–PGE ores occur as irregular, discontinuous, lense-like bodies in the ultramafic rocks. Notably, the olivines in the Ni–PGE ore contain extremely high Ni contents of up to 14,000 ppm, which is significantly higher than the Ni content of olivine in other mafic–ultramafic igneous rocks globally (up to ~5,000 ppm) and in harmony with the associated Ni-rich sulfide assemblage containing pentlandite, millerite and pyrite. Microprobe mapping of olivine from the Ni–PGE ore suggests relatively low and homogeneous S contents and homogeneous distribution of Ni, Mg, Fe, which is inconsistent with the presence of sulfide inclusions in the olivine grains, or diffusion of Ni from interstitial sulfides into the olivine grains. We therefore conclude that Ni substitutes for Mg in the olivine lattice. The clinopyroxenes from the Ni–PGE ore also have unusually high Ni concentrations reaching 1,500 ppm and show a positive correlation with the nickel content of the associated olivine. The Ni_cpx/Ni_olivine is ~0.1 to 0.2 corresponding to high T partitioning of Ni between clinopyroxene and olivine. K _D of 20 can account for the partitioning of nickel between olivine and the sulfide phase, consistent with magmatic equilibration. These data suggest that the olivine, clinopyroxene, and sulfides all crystallized from a basaltic magma with an unexceptionally high Ni content ranging from 300 to 1,100 ppm. The Ni–PGE ores are spatially associated with ultramafic xenoliths. Olivine in these ultramafic xenoliths have relatively high Fo contents (up to 90 mol %) and high Ni contents (up to 5,200 ppm) suggesting that the xenoliths formed from a komatiitic parental magma. It is proposed that assimilation by the Kevitsa magma of massive or semi-massive sulfides associated with komatiitic rocks elevated the Ni content of the magma and resulted in the formation of Ni–PGE ores and related extremely Ni-rich olivines.  相似文献   

Impact of reverberation in flared accretion discs on temporal characteristics of X-ray binaries     

Juri Poutanen 《Monthly notices of the Royal Astronomical Society》2002,332(2):257-270

Observations suggest that accretion discs in many X-ray binaries are likely flared. An outer edge of the disc intercepts radiation from the central X-ray source. Part of that radiation is absorbed and re-emitted in the optical/UV spectral ranges. However, a large fraction of that radiation is reflected and appears in the broad-band X-ray spectrum as a Compton reflection bump. This radiation is delayed and variability is somewhat smeared compared with the intrinsic X-ray radiation. We compute response functions for flat and flared accretion discs and for isotropic and anisotropic X-ray sources. A simple approximation for the response function which is valid in the broad range of the disc shapes and inclinations, inner and outer radii, and the plasma bulk velocity is proposed. We also study the impact of the X-ray reprocessing on temporal characteristics of X-ray binaries such as the power spectral density, auto- and cross-correlation functions, and time/phase lags. We propose a reprocessing model which explains the secondary peaks in the phase lag Fourier spectra observed in Cyg X-1 and other Galactic black hole sources. The position of the peaks could be used to determine the size of the accretion disc.  相似文献