Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Solar activity and Earth's space environment can effect the operation and safety of spacecraft, and they are also the main error source of navigation, positioning, and communication based on radio waves applications system. In this field, the L-band solar radio burst is regarded as a potential threat to Global Navigation Satellite System(GNSS) stability and performance. When the solar radio burst exceeds a threshold value, the radio noise from solar emission will increase dramatically, which can give rise to GNSS receiver tracking loss and positioning failure located in the sunlit hemisphere of the Earth. In this paper, by using the solar radio flux data, L-band scintillation data, and GPS receiver observation network data located in different regions, effect of the 13 December 2006 solar radio burst on GPS observations are investigated in detail. Results show that the disruption caused by this radio burst event is obvious, and the amplitude scintillation events occur and GPS signal losses of lock are detected. Furthermore, the GPS satellite signal locked at several GPS station is interrupted and the observed GPS satellite number is less than 4 during this solar radio burst. The event resulted in GPS service failure for about six minutes. By comparison, those stations located nearby sub-solar point are more serious than that of far away from it.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The outer radiation belt consists mainly of high energy electrons trapped by the Earth's magnetic field. The disturbance of the geomagnetic field caused by the Coronal Mass Ejection (CME) or the Co-rotating Interaction Region (CIR) can result in electron radiation belt variations. According to the variation feature of high energy electron flux in the outer radiation belt during magnetic storms, a novel index referred to as high electron flux fluctuation index was evaluated by using the 5-min resolution sampled electron flux data provided by GOES, and its correlation with geomagnetic Kp index was analyzed. It is found that high electron flux fluctuation index has a good correlation with geomagnetic Kp index, and the new index can be used as an indicator of geomagnetic storm occurrence. In comparison with 3-hour Kp index, which is wildly used in space environment operation prediction system, the suggested index in this paper can alert geomagnetic storm occurrence earlier.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： Solar activity and Earth's space environment can effect the operation and safety of spacecraft, and they are also the main error source of navigation, positioning, and communication based on radio waves applications system. In this field, the L-band solar radio burst is regarded as a potential threat to Global Navigation Satellite System(GNSS) stability and performance. When the solar radio burst exceeds a threshold value, the radio noise from solar emission will increase dramatically, which can give rise to GNSS receiver tracking loss and positioning failure located in the sunlit hemisphere of the Earth. In this paper, by using the solar radio flux data, L-band scintillation data, and GPS receiver observation network data located in different regions, effect of the 13 December 2006 solar radio burst on GPS observations are investigated in detail. Results show that the disruption caused by this radio burst event is obvious, and the amplitude scintillation events occur and GPS signal losses of lock are detected. Furthermore, the GPS satellite signal locked at several GPS station is interrupted and the observed GPS satellite number is less than 4 during this solar radio burst. The event resulted in GPS service failure for about six minutes. By comparison, those stations located nearby sub-solar point are more serious than that of far away from it.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-04
Abstract： The study of the ionosphere responses to Corotating Interaction Regions (CIRs) and Coronal Mass Ejections (CMEs) got much attentions in rencent years. With the comparison of different types of ionosphere response caused by different disturbance sources from solar activity and interplanetary solar wind, morphological changes and physical process of ionospheric storms can be understood more impressively and comprehensively. It provides a possibility to predict ionospheric disturbance states according to different solar wind conditions in advance as well. GPS-TEC data at a mid-latitude station (131 degrees E, 35 degrees N) are used to analyze the ionosphere response during geomagnetic disturbances induced by 109 CIRs and 45 CMEs over the period 2001 to 2009. Firstly, the TEC difference are determined to achieve the information of ionospheric positive or negative storms during the CIR and CME events. The definition of a ionospheric storms is relative TEC greater than or equal to 15% and persisting for more than 4 hours; Secondly, year dependence, seasonal dependence, time delay between ionospheric storms and geomagnetic storms, geomantic storm intensity dependence and time duration of ionospheric storms are analyzed in detail. Analysis results indicate that the types of ionospheric storms vary in different phases of a solar cycle. CIR-driven positive and positive-negative storms are more likely to occur in the declining phase of the solar cycle, while negative phase storms more in solar maximum and negative-positive storms mainly in solar minimum. CME-driven positive storms and negative storms mostly occur in solar maximum. There is no remarkable seasonal difference for the occurrence of different types of ionospheric storms except the positive-negative storms most likely to occur in summer. The time delays between geomagnetic disturbances and the start time of ionospheric storms are-6 to 6 hours in general, but CIR-driven ionopsheric storms involve in a wider range with a time delay of-12 to 24 hours and CME-driven storms is delayed from 6 to 6 hours. Moreover, for CIR-driven ionospheric storms, positive and negative storms mostly occur in main phase of magnetic storms, positive-negative storms mostly in initial and main phase, and negative-positive storms mainly in initial phase. For CME-driven storms, positive, negative and positive-negative storms basically occur in main phase. Our investigation also demonstrates certain correlation between the types of ionospheric storms and the AE maximum indices. Ionopsheric negative storms often occur in stronger geomagnetic activity, with the AE maximum intensity between 800 to 1200nT while positive-negative storms tend to occur with AE maximum intensity higher than 400 nT. Compared to CIR driven storms, AE maximum value during CME driven storms is higher. The duration of CIR-driven storms is longer (1 to 6 days) than that of CME-driven storms (1 to 4 days). The ionosphere response to interplanetary conditions contribute to the study the ionospheric disturbance. Statistical analysis of the ionosphere response to the CIR and CME in Mid-latitude regions indicate that there are some certain correlations among ionospheric changes, solar activities, interplanetary conditions and geomagnetic conditions. The ionospheric storms could be predicted more accurately and meticulously by distinguishing the different types of interplanetary conditions.
Peer Review Status:Awaiting Review
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