23 research outputs found
Results and interpretation of measurements of the light flux in the near-surface layer of the Venusian atmosphere
The characteristics of the field of radiation in the near surface layer of the atmosphere and on the surface of Venus are reported. Optical measurements made during the landing of the descent vehicles are described. The relief of the surface and the amount of dust on it are examined. The spectral relationship of the albedo of the soil and the light flux incident on the surface is discussed
Spectrophotometric experiment on the Verera-11 and Venera-12 descent vehicles: Some results of the analysis of the spectrum of the daytime sky of Venus
The spectra of the daytime sky of Venus were recorded on the Venera-11 and Venera-12 descent vehicles at various altitudes above the planet's surface, within the interval of 4500 to 12,000 Angstroms. The angular distribution of the brightness of the scattered radiation was recorded and the ratio of water and carbon dioxide were studied, with respect to the cloud cover boundaries
The Planetary Fourier Spectrometer (PFS) onboard the European Mars Express mission
International audience; The Planetary Fourier Spectrometer (PFS) for the Mars Express mission is an infrared spectrometer optimised for atmospheric studies. This instrument has a short wave (SW) channel that covers the spectral range from 1700 to 8200.0cm-1 (1.2- 5.5mum) and a long-wave (LW) channel that covers 250- 1700cm-1 (5.5- 45mum). Both channels have a uniform spectral resolution of 1.3cm-1. The instrument field of view FOV is about 1.6o (FWHM) for the Short Wavelength channel (SW) and 2.8o (FWHM) for the Long Wavelength channel (LW) which corresponds to a spatial resolution of 7 and 12 km when Mars is observed from an height of 250 km. PFS can provide unique data necessary to improve our knowledge not only of the atmosphere properties but also about mineralogical composition of the surface and the surface-atmosphere interaction. The SW channel uses a PbSe detector cooled to 200-220 K while the LW channel is based on a pyroelectric ( LiTaO3) detector working at room temperature. The intensity of the interferogram is measured every 150 nm of physical mirrors displacement, corresponding to 600 nm optical path difference, by using a laser diode monochromatic light interferogram (a sine wave), whose zero crossings control the double pendulum motion. PFS works primarily around the pericentre of the orbit, only occasionally observing Mars from large distances. Each measurements take 4 s, with a repetition time of 8.5 s. By working roughly 0.6 h around pericentre, a total of 330 measurements per orbit will be acquired 270 looking at Mars and 60 for calibrations. PFS is able to take measurements at all local times, facilitating the retrieval of surface temperatures and atmospheric vertical temperature profiles on both the day and the night side
Spectroscopy of OSSO and Other Sulfur Compounds Thought to be Present in the Venus Atmosphere
The spectroscopy of cis-OSSO and trans-OSSO is explored and put into the context of the Venusian atmosphere, along with other sulfur compounds potentially present there, namely, S₂O, C₁-S₂O₂, trigonal-S₂O₂, and S₃. UV-vis spectra were calculated using the nuclear ensemble approach. The calculated OSSO spectra are shown to match well with the 320-400 nm near-UV absorption previously measured on Venus, and we discuss the challenges of assigning OSSO as the Venusian near-UV absorber. The largest source of uncertainty is getting accurate concentrations of sulfur monoxide (³SO) in the upper cloud layer of Venus (60-70 km altitude) since the ³SO self-reaction is what causes cis- and trans-OSSO to form. Additionally, we employed the matrix-isolation technique to trap OSSO formed by microwave discharging a gas mixture of argon and SO₂ and then depositing the mixture onto a cold window (6-12 K). Anharmonic vibrational transition frequencies and intensities were calculated at the coupled cluster level to corroborate the matrix-isolation FTIR spectra. The computationally calculated UV-vis and experimentally recorded IR spectra presented in this work aid future attempts at detecting these sulfur compounds in the Venusian atmosphere
Perennial changes and distribution of resources the main species of hunting animals of Russian
The paper presents the assessment of the state in numbers, distribution on the territory and trends of the dynamics at the turn of XX-XXI centuries of the most economically important species of hunting resources in Russia. Materials were obtained on the basis of data questionnaire of «harvest» Services of VNIIOZ which has no analogues in the world on the scale of the covered by territory and the duration of observations (over 80 years) and the analysis of cause-effect relationships of population dynamics. The distribution is shown of the hunting resources by the Federal districts of the country. Predictions of further changes in the number are given by separate species. In the period 1996 to 2015 in Russia it was observed a significant increase in resources of moose, wild boar, roe deer, fox, beaver, a slight increase - in bear, sable, hazel grouse. Reduced in resources is observed in hare, lynx, and in the last five years - in martens. Relatively stable populations are remained in wolf, marmots, wood grouse. Among the ungulates state is alarming in resources of wild boar on some territories in connection with the African swine fever (ASF). The number of wild boar is decreased catastrophically in the Southern and North Caucasian federal districts in connection with the ASF. The current unfavorable situation caused by the ASF may lead to decrease in the number of specie in large parts of the country. Recently, it is observed decrease in interest to hunting on the fur species. The only species which enjoys demand on the international market is sable whose resources over the last two decades remain high with the trend of short stature as a result of ongoing relocation of species. The largest resources of most species of game animals possess the Siberian, Far East and North-West federal districts of the country
Water clouds and dust aerosols observations with PFS MEX at Mars
International audienceObservations of water ice clouds and dust are among the main scientific goals of the Planetary Fourier Spectrometer (PFS), a payload instrument of the European Mars Express mission. We report some results, obtained in three orbits: 37, 41 and 68. The temperature profile, and dust and water ice cloud opacities are retrieved from the thermal infrared (long-wavelength channel of PFS) in a self-consistent way using the same spectrum. Orographic ice clouds are identified above Olympus (orbit 37) and Ascraeus Mons (orbit 68). Both volcanoes were observed near noon at Ls=337° and 342°, respectively. The effective radius of ice particles is preliminary estimated as 1-3 mum, changing along the flanks. The corresponding visual opacity changes in the interval 0.2-0.4 above Olympus and 0.1-0.6 above Ascraeus Mons. In the case of Ascraeus Mons, the ice clouds were observed mainly above the Southern flank of the volcano with maximum opacity near the summit. In the case of Olympus, the clouds were found above both sides of the top. A different type of ice cloud is observed at latitudes above 50°N (orbit 68) in the polar hood: the effective particle radius is estimated to be 4 mum. Below the 1 mb level an inversion in the temperature profiles is found with maximum temperature at around 0.6 mb. Along orbit 68 it appears above Alba Patera, then it increases to the north and decreases above the CO 2 polar cap. Beginning from latitude 20°S above Tharsis (orbit 68), the ice clouds and dust contribute equally to the spectral shape. Further on, the ice clouds are found everywhere along orbit 68 up to the Northern polar cap, except the areas between the Northern flank of Ascraeus Mons (below 10 km) and the edge of Alba Patera. Orbit 41 is shifted from the orbit 68 by roughly 180° longitude and passes through Hellas. Ice clouds are not visible in this orbit at latitudes below 80°S. The dust opacity is anticorrelated with the surface altitude. From 70°S to 25°N latitude the vertical dust distribution follows an exponential law with a scale height of 11.5±0.5 km, which corresponds to the gaseous scale height near noon and indicates a well-mixed condition. The 9 mum dust opacity, reduced to zero surface altitude, is found to be 0.25±0.05, which corresponds to a visual opacity of 0.5-0.7 (depending on the particle size)
Results of Measurements with the Planetary Fourier Spectrometer onboard Mars Express : Clouds and Dust at the End of Southern Summer. A Comparison with OMEGA Images
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