scholarly journals Polar mesospheric clouds observed by Himawari-8

2018 ◽  
Author(s):  
Takuo T. Tsuda ◽  
Yuta Hozumi ◽  
Kento Kawaura ◽  
Keisuke Hosokawa ◽  
Hidehiko Suzuki ◽  
...  
Keyword(s):  
Earth Orbit ◽  
Polar Regions ◽  
Initial Report ◽  
Geostationary Earth Orbit ◽  
Polar Mesospheric Clouds ◽  
The Earth ◽  
Mesospheric Clouds ◽  
Near Future ◽  
Meteorological Satellite

Abstract. We make an initial report on polar mesospheric clouds (PMCs) observed by Himawari-8, the Japanese Geostationary-Earth-Orbit (GEO) meteorological satellite. Heights of the observed PMCs were estimated to be 80–82 km. The PMCs were active only during summertime in both the northern and southern polar regions. These results are concrete evidences of PMCs. PMC observations by Himawari-8 can provide continuous PMC monitoring at every 10 minutes with 3 visible bands from its almost fixed location relative to the Earth, and it would enhance PMC research in the near future.

scholarly journals Initial report on polar mesospheric cloud observations by Himawari-8

2018 ◽  
Vol 11 (11) ◽  
pp. 6163-6168
Author(s):  
Takuo T. Tsuda ◽  
Yuta Hozumi ◽  
Kento Kawaura ◽  
Keisuke Hosokawa ◽  
Hidehiko Suzuki ◽  
...  
Keyword(s):  
Earth Orbit ◽  
Polar Regions ◽  
Initial Report ◽  
Geostationary Earth Orbit ◽  
The Earth ◽  
Near Future ◽  
Meteorological Satellite

Abstract. We provide an initial report on polar mesospheric cloud (PMC) observations by the Japanese Geostationary Earth Orbit (GEO) meteorological satellite Himawari-8. Heights of the observed PMCs were estimated to be 80–82 km. Observed PMCs were active only during summertime in both the northern and southern polar regions. These observations are consistent with known PMC behavior. From its almost fixed location relative to the Earth, Himawari-8 is capable of continuously monitoring PMC every 10 min with three visible bands: blue (0.47 µm), green (0.51 µm), and red (0.64 µm). Thus, Himawari-8 can contribute to PMC research in the near future.

scholarly journals Satellite measurements of the global mesospheric sodium layer

2007 ◽  
Vol 7 (2) ◽  
pp. 5413-5437 ◽  
Author(s):  
Z. Y. Fan ◽  
J. M. C. Plane ◽  
J. Gumbel ◽  
J. Stegman ◽  
E. J. Llewellyn
Keyword(s):  
Lower Thermosphere ◽  
Optimal Estimation ◽  
Fold Increase ◽  
Peak Height ◽  
Equatorial Region ◽  
Polar Regions ◽  
Satellite Measurements ◽  
Density Profiles ◽  
Polar Mesospheric Clouds ◽  
Mesospheric Clouds

Abstract. Optimal estimation theory is used to retrieve the absolute Na density profiles in the mesosphere/lower thermosphere from limb-scanning measurements of the Na radiance at 589 nm in the dayglow. Two years of observations (2003 and 2004), recorded by the OSIRIS spectrometer on the Odin satellite, have been analysed to yield the seasonal and latitudinal variation of the Na layer column abundance, peak height, and peak width. The layer shows little seasonal variation at low latitudes, but the winter/summer ratio increases from a factor of ~3 at mid-latitudes to ~10 in the polar regions. Comparison of the measurements made at about 06:00 and 18:00 LT shows little diurnal variation in the layer, apart from the equatorial region where, during the equinoxes, there is a two-fold increase in Na density below 94 km between morning and evening. This is most likely caused by the strong downward wind produced by the diurnal tide between ~02:00 and 10:00 LT. The dramatic removal of Na below 85 km at latitudes above 50° during summer is explained by the uptake of sodium species on the ice surfaces of polar mesospheric clouds, which were simultaneously observed by the Odin satellite.

scholarly journals First climatology of polar mesospheric clouds from GOMOS/ENVISAT stellar occultation instrument

2010 ◽  
Vol 10 (6) ◽  
pp. 2723-2735 ◽  
Author(s):  
K. Pérot ◽  
A. Hauchecorne ◽  
F. Montmessin ◽  
J.-L. Bertaux ◽  
L. Blanot ◽  
...  
Keyword(s):  
Sampling Rate ◽  
Solar Light ◽  
Polar Regions ◽  
Data Set ◽  
Polar Mesospheric Clouds ◽  
Atmospheric Molecules ◽  
The North ◽  
Stellar Occultation ◽  
Mesospheric Clouds ◽  
Synchronous Orbit

Abstract. GOMOS (Global Ozone Monitoring by Occultation of Stars), on board the European platform ENVISAT launched in 2002, is a stellar occultation instrument combining four spectrometers and two fast photometers which measure light at 1 kHz sampling rate in the two visible channels 470–520 nm and 650–700 nm. On the day side, GOMOS does not measure only the light from the star, but also the solar light scattered by the atmospheric molecules. In the summer polar days, Polar Mesospheric Clouds (PMC) are clearly detected using the photometers signals, as the solar light scattered by the cloud particles in the instrument field of view. The sun-synchronous orbit of ENVISAT allows observing PMC in both hemispheres and the stellar occultation technique ensures a very good geometrical registration. Four years of data, from 2002 to 2006, are analyzed up to now. GOMOS data set consists of approximately 10 000 cloud observations all over the eight PMC seasons studied. The first climatology obtained by the analysis of this data set is presented, focusing on the seasonal and latitudinal coverage, represented by global maps. GOMOS photometers allow a very sensitive PMC detection, showing a frequency of occurrence of 100% in polar regions during the middle of the PMC season. According to this work mesospheric clouds seem to be more frequent in the Northern Hemisphere than in the Southern Hemisphere. The PMC altitude distribution was also calculated. The obtained median values are 82.7 km in the North and 83.2 km in the South.

scholarly journals First climatology of polar mesospheric clouds from GOMOS/ENVISAT stellar occultation instrument

2009 ◽  
Vol 9 (6) ◽  
pp. 25599-25632
Author(s):  
K. Pérot ◽  
A. Hauchecorne ◽  
F. Montmessin ◽  
J.-L. Bertaux ◽  
L. Blanot ◽  
...  
Keyword(s):  
Sampling Rate ◽  
Solar Light ◽  
Polar Regions ◽  
Data Set ◽  
Polar Mesospheric Clouds ◽  
Atmospheric Molecules ◽  
The North ◽  
Stellar Occultation ◽  
Mesospheric Clouds ◽  
Synchronous Orbit

Abstract. GOMOS (Global Ozone Monitoring by Occultation of Stars), on board the European platform ENVISAT launched in 2002, is a stellar occultation instrument combining four spectrometers and two fast photometers which measure light at 1 kHz sampling rate in the two visible channels 470–520 nm and 650–700 nm. On the day side, GOMOS does not measure only the light from the star, but also the solar light scattered by the atmospheric molecules. In the summer polar days, Polar Mesospheric Clouds (PMC) are clearly detected using the photometers signals, as the solar light scattered by the cloud particles in the instrument field of view. The sun-synchronous orbit of ENVISAT allows observing PMC in both hemispheres and the stellar occultation technique ensures a very good geometrical registration. Four years of data, from 2002 to 2006, are analyzed up to now. GOMOS data set consists of approximately 10 000 cloud observations all over the eight PMC seasons studied. The first climatology obtained by the analysis of this data set is presented, focusing on the seasonal and latitudinal coverage, represented by global maps. GOMOS photometers allow a very sensitive PMC detection, showing a frequency of occurrence of 100% in polar regions during the middle of the PMC season. According to this work mesospheric clouds seem to be more frequent in the Northern Hemisphere than in the Southern Hemisphere. The PMC altitude distribution was also calculated. The obtained median values are 82.7 km in the North and 83.2 km in the South.

scholarly journals Satellite measurements of the global mesospheric sodium layer

2007 ◽  
Vol 7 (15) ◽  
pp. 4107-4115 ◽  
Author(s):  
Z. Y. Fan ◽  
J. M. C. Plane ◽  
J. Gumbel ◽  
J. Stegman ◽  
E. J. Llewellyn
Keyword(s):  
Lower Thermosphere ◽  
Optimal Estimation ◽  
Fold Increase ◽  
Peak Height ◽  
Equatorial Region ◽  
Polar Regions ◽  
Satellite Measurements ◽  
Density Profiles ◽  
Polar Mesospheric Clouds ◽  
Mesospheric Clouds

Abstract. Optimal estimation theory is used to retrieve the absolute Na density profiles in the mesosphere/lower thermosphere from limb-scanning measurements of the Na radiance at 589 nm in the dayglow. Two years of observations (2003 and 2004), recorded by the OSIRIS spectrometer on the Odin satellite, have been analysed to yield the seasonal and latitudinal variation of the Na layer column abundance, peak height, and peak width. The layer shows little seasonal variation at low latitudes, but the winter/summer ratio increases from a factor of ~3 at mid-latitudes to ~10 in the polar regions. Comparison of the measurements made at about 06:00 and 18:00 LT shows little diurnal variation in the layer, apart from the equatorial region where, during the equinoxes, there is a two-fold increase in Na density below 94 km between morning and evening. This is most likely caused by the strong downward wind produced by the diurnal tide between ~02:00 and 10:00 LT. The dramatic removal of Na below 85 km at latitudes above 50° during summer is explained by the uptake of sodium species on the ice surfaces of polar mesospheric clouds, which were simultaneously observed by the Odin satellite.

scholarly journals Space IT platforms: challenges of the XXI century

2018 ◽  
Vol 44 ◽  
pp. 00047
Author(s):  
Vadim Korablyov ◽  
Alexander Zheleznyakov
Keyword(s):  
21St Century ◽  
Rapid Growth ◽  
Space Exploration ◽  
Earth Orbit ◽  
Near Space ◽  
The Earth ◽  
Asteroid Hazard ◽  
The Stability ◽  
Intellectual Potential ◽  
Near Future

More than half a century of man-in-space exploration not only demonstrated the new manufacturing capabilities of the countries involved in the study of distant and near space, but also presented the main challenges that humanity will face in the exploration of the space in the first half of the 21st century. One of these challenges is the rapid growth in a number of satellites used not only by government structures, but also by private sector. This problem gives rise to another one – ensuring the safety of the satellites flights and contamination of the earth orbit by man-made objects. A particular problem is the growing militarization of the space. There is another natural challenge such as a cometary-asteroid hazard. In the near future, humanity has to answer these challenges. This is important for two reasons. Firstly, only overcoming them, we will be able to continue our expansion in the space. And, secondly, only by solving the encountered problems, we will be able to maintain the stability on the Earth. An important factor for a successful response to the challenges is international cooperation in space, which allows combining the resources of space powers including intellectual potential. In this case, we can rely on the soonest achievement of the set goals. Of course, this will mark new frontiers, which will be a challenge for the next generations.

scholarly journals Data association and uncertainty pruning for tracks determined on short arcs

2020 ◽  
Vol 132 (1) ◽  
Author(s):  
Laura Pirovano ◽  
Gennaro Principe ◽  
Roberto Armellin
Keyword(s):  
Optimization Problems ◽  
Data Association ◽  
Earth Orbit ◽  
Orbital State ◽  
Geostationary Earth Orbit ◽  
Multiple Observations ◽  
Observation Strategies

AbstractWhen building a space catalogue, it is necessary to acquire multiple observations of the same object for the estimated state to be considered meaningful. A first concern is then to establish whether different sets of observations belong to the same object, which is the association problem. Due to illumination constraints and adopted observation strategies, small objects may be detected on short arcs, which contain little information about the curvature of the orbit. Thus, a single detection is usually of little value in determining the orbital state due to the very large associated uncertainty. In this work, we propose a method that both recognizes associated observations and sequentially reduces the solution uncertainty when two or more sets of observations are associated. The six-dimensional (6D) association problem is addressed as a cascade of 2D and 4D optimization problems. The performance of the algorithm is assessed using objects in geostationary Earth orbit, with observations spread over short arcs.

scholarly journals Performance evaluation of multi-GNSSs navigation in super synchronous transfer orbit and geostationary earth orbit

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Tao Shi ◽  
Xuebin Zhuang ◽  
Liwei Xie
Keyword(s):  
Global Navigation Satellite System ◽  
Autonomous Navigation ◽  
Satellite System ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Geostationary Earth Orbit ◽  
Beidou Navigation Satellite System ◽  
Transfer Orbit ◽  
High Orbit ◽  
Global Navigation Satellite

AbstractThe autonomous navigation of the spacecrafts in High Elliptic Orbit (HEO), Geostationary Earth Orbit (GEO) and Geostationary Transfer Orbit (GTO) based on Global Navigation Satellite System (GNSS) are considered feasible in many studies. With the completion of BeiDou Navigation Satellite System with Global Coverage (BDS-3) in 2020, there are at least 130 satellites providing Position, Navigation, and Timing (PNT) services. In this paper, considering the latest CZ-5(Y3) launch scenario of Shijian-20 GEO spacecraft via Super-Synchronous Transfer Orbit (SSTO) in December 2019, the navigation performance based on the latest BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), Galileo Navigation Satellite System (Galileo) and GLObal NAvigation Satellite System (GLONASS) satellites in 2020 is evaluated, including the number of visible satellites, carrier to noise ratio, Doppler, and Position Dilution of Precision (PDOP). The simulation results show that the GEO/Inclined Geo-Synchronous Orbit (IGSO) navigation satellites of BDS-3 can effectively increase the number of visible satellites and improve the PDOP in the whole launch process of a typical GEO spacecraft, including SSTO and GEO, especially for the GEO spacecraft on the opposite side of Asia-Pacific region. The navigation performance of high orbit spacecrafts based on multi-GNSSs can be significantly improved by the employment of BDS-3. This provides a feasible solution for autonomous navigation of various high orbit spacecrafts, such as SSTO, MEO, GEO, and even Lunar Transfer Orbit (LTO) for the lunar exploration mission.

scholarly journals A review of the SCOSTEP’s 5-year scientific program VarSITI—Variability of the Sun and Its Terrestrial Impact

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kazuo Shiokawa ◽  
Katya Georgieva
Keyword(s):  
Solar Wind ◽  
Interplanetary Space ◽  
Solar Wind Plasma ◽  
The Sun ◽  
Scientific Program ◽  
Solar Cycles ◽  
Grand Minimum ◽  
The Earth ◽  
Earth Connection ◽  
Near Future

AbstractThe Sun is a variable active-dynamo star, emitting radiation in all wavelengths and solar-wind plasma to the interplanetary space. The Earth is immersed in this radiation and solar wind, showing various responses in geospace and atmosphere. This Sun–Earth connection variates in time scales from milli-seconds to millennia and beyond. The solar activity, which has a ~11-year periodicity, is gradually declining in recent three solar cycles, suggesting a possibility of a grand minimum in near future. VarSITI—variability of the Sun and its terrestrial impact—was the 5-year program of the scientific committee on solar-terrestrial physics (SCOSTEP) in 2014–2018, focusing on this variability of the Sun and its consequences on the Earth. This paper reviews some background of SCOSTEP and its past programs, achievements of the 5-year VarSITI program, and remaining outstanding questions after VarSITI.

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