Specific problems of ore prospection geophysics in regions of arid climate     

Miroslav Krs 《Pure and Applied Geophysics》1972,98(1):163-172

Summary The present communication deals with problems that are common to the application of some geophysical methods in arid regions. Typical examples of using geothermic methods, D.C. and A.C. electrical and radiometric methods in the Eastern Desert of Egypt are presented. The conclusions were derived from a great number of measurements and are all associated with the physical properties of rocks on or near the surface under desert conditions.  相似文献   

Size-resolved characteristics of inorganic ionic species in atmospheric aerosols at a regional background site on the South African Highveld     

Andrew D. Venter  Pieter G. van Zyl  Johan P. Beukes  Jan-Stefan Swartz  Miroslav Josipovic  Ville Vakkari  Lauri Laakso  Markku Kulmala 《Journal of Atmospheric Chemistry》2018,75(3):285-304

Aerosols consist of organic and inorganic species, and the composition and concentration of these species depends on their sources, chemical transformation and sinks. In this study an assessment of major inorganic ions determined in three aerosol particle size ranges collected for 1 year at Welgegund in South Africa was conducted. SO₄^2? and ammonium (NH₄⁺) dominated the PM₁ size fraction, while SO₄^2? and nitrate (NO₃) dominated the PM_1–2.5 and PM_2.5–10 size fractions. SO₄^2? had the highest contribution in the two smaller size fractions, while NO₃^? had the highest contribution in the PM_2.5–10 size fraction. SO₄^2? and NO₃^? levels were attributed to the impacts of aged air masses passing over major anthropogenic source regions. Comparison of inorganic ion concentrations to levels thereof within a source region influencing Welgegund, indicated higher levels of most species within the source region. However, the comparative ratio of SO₄^2? was significantly lower due to SO₄^2? being formed distant from SO₂ emissions and submicron SO₄^2? having longer atmospheric residencies. The PM at Welgegund was determined to be acidic, mainly due to high concentrations of SO₄^2?. PM₁ and PM_1–2.5 fractions revealed a seasonal pattern, with higher inorganic ion concentrations measured from May to September. Higher concentrations were attributed to decreased wet removal, more pronounced inversion layers trapping pollutants, and increases in household combustion and wild fires during winter. Back trajectory analysis also revealed higher concentrations of inorganic ionic species corresponding to air mass movements over anthropogenic source regions.  相似文献   

Developing a reduced-form ensemble of climate change scenarios for Europe and its application to selected impact indicators     

Martin Dubrovsky  Miroslav Trnka  Ian P. Holman  Eva Svobodova  Paula A. Harrison 《Climatic change》2015,128(3-4):169-186

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Radio-continuum study of the nearby sculptor group galaxies. Part 3: NGC 7793 at λ=12.2, 6 and 3 cm     

Timothy J. Galvin  Miroslav D. Filipović  Nicholas F. H. Tothill  Evan J. Crawford  Andrew N. O’Brien  Nicholas Seymour  Thomas G. Pannuti  Alekzander R. Kosakowski  Biswas Sharma 《Astrophysics and Space Science》2014,353(2):603-611

We re-examine a series of archived centimetre radio-continuum observations (λ=16, 6 and 3 cm) focusing on NGC?7793 using the Australia Telescope Compact Array. These new images are both very sensitive (σ=0.011 mJy/beam) and feature reasonably high angular resolution (down to <3″). Using these images, a total of 76 discrete radio sources are identified, of which 57 have been classified. We also studied the radio component of the micro-quasar NGC7793-S26 which shows two distinct regions of somewhat steep spectral index (α) between ?0.3 and ?0.7.  相似文献