[en] Disturbance torques in Low Earth Orbits may present a harsh environment for the successful operation of small satellite missions. The effects of gravity-gradient and aerodynamic torques are studied individually at various altitudes for low Earth orbit. Results show that for a basic 2U CubeSat, the gravity-gradient torque is highly perturbing, whereas the effect of aerodynamic torque is established to be so dominant that it offers attitude stabilization in lower altitudes; and may be used as a means of passive attitude stabilization. (paper)

[en] This paper discusses the implementation of an electronic pseudolite close-range navigation system provided that one of the pseudolites is located at a certain altitude. The authors have developed principles for building a timescale for this system to solve the problem of mutual synchronization of the pseudolites. The principle of retransmitting the signals from all the pseudolites to one reference station is considered as the basis for this system. (paper)

[en] High altitude or brisket disease of cattle is common at high altitude areas. It is characterized by right ventricular hypertrophy and edema of the chest and brisket, because of reduced blood oxygen saturation at high elevation. It is similar to altitude sickness in humans and frequently ends with the death of the affected animal unless transferred to lower altitude. The incidence and severity of the disease increase with altitude. Pulmonary artery pressure (PAP) is an indicator of proneness to the disease. High values (>50 mm HG) indicate high risk and low values (<35 mmHG) indicate resistance to the disease. Analyses of heritability of PAP, mostly performed on Angus cattle in the Rocky Mountains at altitudes of 2000-3800 m indicate a relatively high heritability, in the range of 0.30-0.50. This provides options for selection, which is performed routinely in the Rocky Mountains. The Semien Mountains are the highest mountain range of Ethiopia, peaking at the Ras Dashen (4620 m). Cattle are kept at altitudes of up to almost 4000 m. Along the western side of the mountain range, there is a rather continuous drop in altitude down to about 600 m, over a rather short distance (250 km). The cattle in the region are partly of different type (Zebu, Sanga) and partly a mixture (Zenga = Zebu x Sanga). The phenotypic differentiation in terms of body size along levels of altitude is strong. A study was conducted to assess the prevalence rate of high altitude disease and as well as to compare adaptive characteristics of indigenous cattle populations and their crosses with European types towards altitude, in particular, to high altitude disease. In January 2007, 218 animals situated within an altitude range of 1730 - 3500 m were tested for PAP by an experienced veterinarian from Colorado State University. Local breeds and crosses with Holstein Friesian and Jersey were measured. The results in Table I indicate that no sign of brisket disease is observed among the studied populations. All PAP scores (21- 47 mm Hg) fall within the range of low to moderate risks. Differences in means were not significant for any pair of populations. Some of the readings (values <28 mm HG) for the Semien cattle group measured at 3500 m are out of the range of readings of approx. 100,000 cattle that the veterinarian has taken in the Rocky mountains in the course of 20 years. Crosses of the local cattle with Holstein Friesian and Jersey were not more prone to brisket disease than local cattle measured at the same altitudes. In a study comparing PAP readings in yak, cattle and their crosses, the crosses had equally low PAP readings as the yaks. Yaks are known to be resistant to high altitude disease due to an adaptation of vascular system, indicated by thin-walled small pulmonary arteries. The authors speculated about an autosomal dominant gene transmitting genetic attenuation of the hypoxic vasoconstrictor response. We conclude that cattle breeds of North Western Ethiopia are genetically adapted to high altitude. To get an insight on the mechanism of adaptation an in depth histological study on the internal anatomy of cardiovascular and respiratory systems of these genotypes is currently being undertaken. (author)

[en] Complete text of publication follows. In 2005 (Taylor et al., 2005-Earth Observation with CHAMP Results from Three Years in Orbit) computed and interpreted a CHAMP satellite magnetic anomaly map, at 400 km altitude, over the Pannonian Basin and surrounding region using the method of Alsdorf et al. (1994). This area was chosen since it has one of the thinnest continental crusts in Europe and is the region of complex tectonic structures. The future SWARM satellite constellation of three spacecraft, with one at a high altitude and the other two lower, will initially be at the same altitude as CHAMP but eventually they will descent to a lower altitude. We recomputed our most recent satellite magnetic anomaly map, using the spherical-cap method of Haines (1985), the technique of Alsdorf et al. (1994) and from spherical harmonic coefficients of MF6 (Maus et al., 2008) employing the latest and lowest altitude CHAMP data, in order to evaluate and reinterpret these newer data to determine the advantage of lower altitude satellite data. The SWARM constellation will have the two lowest altitude satellites flying abreast, with a separation of between ca. 150 to 200 km. to record the horizontal magnetic gradient. Since the CHAMP satellite has been in orbit for eight years and has obtained an extensive range of data, both vertically and horizontally there is a large enough data base to compute the magnetic gradients over the Pannonian Basin region using the many orbits. We computed the magnetic anomaly gradients in order to determine how these component data will improve our interpretation and to preview what the SWARM mission will reveal with reference to the horizontal gradient anomalies.

[en] Ali in Tibet, 5100 m above sea level, is one of the most suitable locations in the world for infrared spectral observations. The atmospheric transmittances at Ali Observatory and Mauna Kea Observatory were calculated by MODTRAN using radiosonde data. The results were 0.848 and 0.789 respectively which indicated better conditions at Ali Observatory. A self-made instrument with a 320×256-pixel HgCdTe infrared focal plane array and a 7.5-cm diameter telescope was utilized for the actual measurements. Without the help of standard stars, the on-site and real-time atmospheric transmittance can be obtained as 0.831 by fitting the relation between the measured atmospheric radiation intensity and the zenith angle based on radiation transfer equations. This paper firstly reports the atmospheric transmittance in the M’ band (4.605–4.755 μm) at the 5100 m-altitude Ali observatory by actual measurement. It shows that the high-altitude Ali observatory with sufficiently low water vapor content is suitable for observation in the mid-infrared bands. (paper)

[en] The possible relation of a major sudden stratospheric warming (SSW) with the mid-latitude surface weather conditions was investigated using data from the ERA-Interim and NCEP–NCAR reanalyzes. An important feature of the SSW event is the impact on lower altitudes, when temperature and wind anomalies descend downward into the high- and mid-latitude troposphere during the weeks or even month and influence the surface weather [1, 2]. Owing to known SSW impacts on the surface weather [2], we consider the possible relation of the SSW event in winter 2018 to cold weather anomaly in the Northern Ukraine and North-East China in February 2018.

[en] The Zhoubi Suanjing, one of the most important ancient Chinese books on mathematical astronomy, was compiled about 100 BC in the Western Han dynasty (BC 206 - AD 23). We study the gnomon shadow lengths for the 24 solar terms as recorded in the book. Special attention is paid to the so-called law of 'cun qian li', which says the shadow length of a gnomon of 8 chi (about 1.96 m) high will increase (or decrease) 1 cun (1/10 chi) for every 1000 li (roughly 400 km) the gnomon moves northward (or southward). From these data, one can derive the time and location of the observations. The results, however, do not fit historical facts. We suggest that compilers of the Zhoubi Suanjing must have modified the original data according to the law of 'cun qian li'. Through reversing the situation, we recovered the original data, our analysis of which reveals the best possible observation time as 564 BC and the location of observation as 35.78 deg. N latitude. We conclude that this must be the earliest records of solar meridian observations in China. In the meantime, we give the errors of solar altitudes for the 24 solar terms. The average deviation is 5.22 deg., and the mean absolute deviation is 5.52 deg., signifying the accuracy of astronomical calculations from that time.

[en] The discovery of cosmic rays by Victor Hess during a balloon flight in 1912 at an altitude of 5350 m would not have been possible without the more than one hundred years development of scientific ballooning. The discovery of hot air and hydrogen balloons and their first flights in Europe is shortly described. Scientific ballooning was mainly connected with activities of meteorologists. It was also the geologist and meteorologist Franz Linke, who probably observed first indications of a penetrating radiation whose intensity seemed to increase with the altitude. Karl Bergwitz and Albert Gockel were the first physicists studying the penetrating radiation during balloon flights. The main part of the article deals with the discovery of the extraterrestrial radiation by V. Hess and the confirmation by Werner Kolhörster

[en] Highlights: • VIRTIS(M)-VEX measurements are used to retrieve mesospheric temperature profiles. • Results for two independent retrieval methods (Chahine, Bayes) are compared. • Temperature profiles are in good agreement for both algorithms. • Corresponding standard deviations do not exceed 5 K for altitudes above 59 km. • Cold collar and hot polar regions are observed. We present vertical temperature profiles derived by two different retrieval methods from nighttime radiation measurements performed by VIRTIS(M)-VEx (Visible and Infrared Thermal Imaging Spectrometer, M channel—Venus Express). The Bayesian approach to the optimal estimation method and the relaxation method are applied in this study. This is a first attempt to present and compare results obtained from two independent methods. It allows us to be more convinced of our interpretation. After comparison of temperature profiles we conclude that both retrieval methods are able to sound the atmospheric layers higher than 59 km (In our conclusion we have no preference for any approach. Two methodologies are of equivalent value. Both methods resolve temperature inversions at high altitudes (∼84 km), the quality of fits for all observations is equally well. Only for the Bayesian approach, the retrieval uncertainty above 62 km up to 95 km is less than 2 K. A disadvantage of this method is the time-consuming calculation of weighting functions. The atmospheric temperatures over the “cold collar” region located at 60°S–75°S (60–70 km) are ∼10 K smaller than for latitudes poleward of 75°S (polar region). The cold collar region is seen very clearly in our results for both methods.

[en] Complete text of publication follows. Although many new details on the properties of mesospheric ice particles that form Polar Mesospheric Clouds (PMCs) and also cause polar mesospheric summer echoes have been recently revealed, certain aspects of mesospheric ice microphysics and dynamics still remain open. The detailed relation between PMC parameters and properties of their environment, as well as interseasonal and interhemispheric differences and trends in PMC properties that are possibly related to global change, are among those open questions. In this work, mesospheric temperature and water vapor concentration measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite are used to study the properties of PMCs with respect to the surrounding atmosphere. The cloud parameters, namely location, brightness, and altitude, are obtained from the observations made by the Optical Spectrograph and Infrared Imager System (OSIRIS) on the Odin satellite. About a thousand of simultaneous common volume measurements made by SABER and OSIRIS in both hemispheres from 2002 until 2008 are used. The correlation between PMC brightness (and occurrence rate) and temperatures at PMC altitudes and at the mesopause is analysed. The relation between PMC parameters, frost point temperature, and gaseous water vapor content in and below the cloud is also discussed. Interseasonal and interhemispheric differences and trends in the above parameters, as well as in PMC peak altitudes and mesopause altitudes are evaluated.