Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Combining the GRO (Global Navigation Satellite System Radio Occultation GRO) and LRO (Low Earth Orbit Radio Occultation) techniques to probe the Earth's atmosphere is a main development direction of RO. In this study, the mathematical criteria of a RO event have been described. Then the effects of the main orbit parameters of LEO satellite on the RO events amount and their global distribution have discussed by a simulation study. The results showed that the lower the LEO satellite orbit is, the more GRO events are; when the inclination is between 30癮nd 75� there are more GRO events and their Earth coverage is higher. The LRO events distribute on the Earth evenly when the LEO-LEO RO satellite set in the polar orbits. This study can provide a scientific reference for GRO and LRO satellite constellation design.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： By utilizing data obtained on Chinese satellite in the middle Earth orbit from solar activity descending phase to solar activity ascending phase, the properties of high energy electron environment in the middle Earth orbit are analyzed, such as spatial distribution, flux intensity, temporal variations, and response to geomagnetic storms. The investigating results indicate that the spatial distribution of high energy electron in the middle Earth orbit is stable;the fluxes of electrons decrease with energy increasing;the high energy electron environment is a dynamical system which disturbs evidently on different timescales;the evolvement of this system is stimulated by geomagnetic storms, but the correlation between the evolvement and the storms is nonlinear.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-03
Abstract： After spacecraft launched into space environment, molecule contamination and tiny particle contamination deposit on spacecraft surface and constitute the surface contamination layer. This contamination phenomenon has different levels of negative impacts on some technical systems. The on-orbit detection results of spacecraft surface contamination both in China and abroad were discussed. Surface contamination deposition changes and control factors were preliminarily evaluated. The result shows that deposition changes of surface contamination within the first 1 to 2 years after launch are controlled by the spacecraft outgassing mass by itself, outgassing rate, spacecraft surface temperature and air flow direction. The deposition mass within early period is larger, which is controlled by more surface outgassing by spacecraft itself within early period and higher deposition rate after launch. And the deposition mass is more in the ram area than in the yield area. The surface deposition in the later period shows obvious drop or slow fluctuations, and possesses omnidirectional characteristics. Some control factors with omnidirectional effect were discussed, among which high-energy particle flux and solar ultraviolet radiation flux may be the main control factors.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-03
Abstract： The radio occultation (RO) technique using signals from the global navigation satellite system, is widely used to observe the atmosphere for applications such as numerical weather prediction (NWP) and global climate monitoring. Since 1995, there have been turborogue sounder on board global positioning system/meteorology, black jack sounder on board challenging minisatellite payload and gravity recovery and climate experiment, IGOR sounder on board constellation observing system for meteorology, ionosphere and climate, GRAS on board meteorological operational, which have been recieving a large number of RO data, but their observed signals come only from global positioning system (GPS). These RO data have been wildly used in NWP and climate monitoring, however they cannot meet the requirements for high accuracy and real time atmosphere observation, in this case compatible RO sounder to obtain more RO observations is significant. Global navigation satellite system occultation sounder (GNOS) on board the fengyun3 C (FY3 C) satellite, which is the first Bei Dou system (BDS)/GPS compatible RO sounder in the world, was launched on 23 September 2013. Up to now, lots of RO observations have been obtained. In this study, the components of GNOS are introduced; one-day GNOS RO events and their global distribution are analyzed; compared with the GPS RO observations, the accuracy and consistency of BDS real-time positioning results and BDS RO products are analyzed. The preliminary results show that the BDS can enhance the number of RO events by 33.3%; the average deviation and standard deviation of BDS real time positioning results are 6 m and 7 m, respectively; the BDS/GPS difference standard deviation of refrectivity, temperature, humidity, pressure and ionospheric electron density are lower than 2%, 2 K, 1.5 g/kg, 2%, and 15.6%, respectively. The BDS observations/products are consistent with those of GPS, therefore BDS RO products can bring benefit to numerical wheather prediction and global chlimate change analysis.
Peer Review Status:Awaiting Review
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