scholarly journals GNSS Radio Occultation Constellation Observing System Experiments

2014 ◽  
Vol 142 (2) ◽  
pp. 555-572 ◽  
Author(s):  
Peter Bauer ◽  
Gábor Radnóti ◽  
Sean Healy ◽  
Carla Cardinali
Keyword(s):  
Radio Occultation ◽  
Lower Stratosphere ◽  
Satellite System ◽  
Model Bias ◽  
Upper Troposphere ◽  
Aircraft Observations ◽  
Data Volume ◽  
Occultation Data ◽  
Global Navigation Satellite ◽  
Radio Occultation Data

Abstract Observing system experiments within the operational ECMWF data assimilation framework have been performed for summer 2008 when the largest recorded number of Global Navigation Satellite System (GNSS) radio occultation observations from both operational and experimental satellites were available. Constellations with 0%, 5%, 33%, 67%, and 100% data volume were assimilated to quantify the sensitivity of analysis and forecast quality to radio occultation data volume. These observations mostly constrain upper-tropospheric and stratospheric temperatures and correct an apparent model bias that changes sign across the upper-troposphere–lower-stratosphere boundary. This correction effect does not saturate with increasing data volume, even if more data are assimilated than available in today’s analyses. Another important function of radio occultation data, namely, the anchoring of variational radiance bias corrections, is demonstrated in this study. This effect also does not saturate with increasing data volume. In the stratosphere, the anchoring by radio occultation data is stronger than provided by radiosonde and aircraft observations.

scholarly journals Observing upper troposphere–lower stratosphere climate with radio occultation data from the CHAMP satellite

2007 ◽  
Vol 31 (1) ◽  
pp. 49-65 ◽  
Author(s):  
Ulrich Foelsche ◽  
Michael Borsche ◽  
Andrea K. Steiner ◽  
Andreas Gobiet ◽  
Barbara Pirscher ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Lower Stratosphere ◽  
Upper Troposphere ◽  
Champ Satellite ◽  
Occultation Data ◽  
Radio Occultation Data

scholarly journals Short vertical-wavelength gravity wave activities in the upper troposphere lower stratosphere observed with global navigation satellite system radio occultation under different QBO phases

2021 ◽  
Vol 893 (1) ◽  
pp. 012007
Author(s):  
Firas Rasyad ◽  
Tri Wahyu Hadi ◽  
Noersomadi
Keyword(s):  
Global Navigation Satellite System ◽  
Radio Occultation ◽  
Lower Stratosphere ◽  
Satellite System ◽  
Navigation Satellite ◽  
Vertical Wavelength ◽  
Upper Troposphere ◽  
Research Activities ◽  
Global Navigation ◽  
Global Navigation Satellite

Abstract Gravity Waves (GWs) are believed to play important role in the generation of the driving force of the stratospheric Quasi-Biennial Oscillation (QBO). Deep convection in the equatorial region can generate large amount of GW with short vertical wavelength (λz <1 km) but studies of these wave activities in the upper troposphere lower stratosphere (UTLS) region are still limited. Recent advances in Global Navigation Satellite System (GNSS) Radio Occultation (RO) retrieval techniques have made it possible to derive global temperature profile with vertical resolution of less than 1 km. In this research, activities of GW with λz from 0.5 to 3.5 km in the UTLS region of 20-27 km heights are identified by calculating the GW potential energy (E p). Correlation between GW activities and QBO phases is examined using 50 hPa zonal wind as the QBO index. The results show that during both easterly and westerly QBO phases, the GW E p value increases gradually with time and reaches its peak in the transition periods. This pattern is seen in E p with all vertical wavelengths between 0.5-3.5 km but the percentage value of E p for λz<1 km is higher during the transition from westerly to easterly QBO. The GW E p values exhibit downward propagation with the QBO phase but there are also discernible upward propagations of GW activities below 24 km height and intersect those two bring large changes in QBO phases. Additionally, higher percentage of E p with λz<1 km is also found to be associated with El Niño events.

scholarly journals Application of the Fengyun 3 C GNSS occultation sounder for assessing the global ionospheric response to a magnetic storm event

2019 ◽  
Vol 12 (3) ◽  
pp. 1483-1493 ◽  
Author(s):  
Weihua Bai ◽  
Guojun Wang ◽  
Yueqiang Sun ◽  
Jiankui Shi ◽  
Guanglin Yang ◽  
...  
Keyword(s):  
Magnetic Storm ◽  
Radio Occultation ◽  
Correlation Coefficients ◽  
Satellite System ◽  
Storm Event ◽  
Calibration Data ◽  
Long Term Stability ◽  
Negative Effect ◽  
Occultation Data ◽  
Global Navigation Satellite

Abstract. The rapid advancement of global navigation satellite system (GNSS) occultation technology in recent years has made it one of the most advanced space-based remote sensing technologies of the 21st century. GNSS radio occultation has many advantages, including all-weather operation, global coverage, high vertical resolution, high precision, long-term stability, and self-calibration. Data products from GNSS occultation sounding can greatly enhance ionospheric observations and contribute to space weather monitoring, forecasting, modeling, and research. In this study, GNSS occultation sounder (GNOS) results from a radio occultation sounding payload aboard the Fengyun 3 C (FY3-C) satellite were compared with ground-based ionosonde observations. Correlation coefficients for peak electron density (NmF2) derived from GNOS Global Position System (GPS) and Beidou navigation system (BDS) products with ionosonde data were higher than 0.9, and standard deviations were less than 20 %. Global ionospheric effects of the strong magnetic storm event in March 2015 were analyzed using GNOS results supported by ionosonde observations. The magnetic storm caused a significant disturbance in NmF2 level. Suppressed daytime and nighttime NmF2 levels indicated mainly negative storm conditions. In two longitude section zones of geomagnetic inclination between 40 and 80∘, the results of average NmF2 observed by GNOS and ground-based ionosondes showed the same basic trends during the geomagnetic storm and confirmed the negative effect of this storm event on the ionosphere. The analysis demonstrates the reliability of the GNSS radio occultation sounding instrument GNOS aboard the FY3-C satellite and confirms the utility of ionosphere products from GNOS for statistical and event-specific ionospheric physical analyses. Future FY3 series satellites and increasing numbers of Beidou navigation satellites will provide increasing GNOS occultation data on the ionosphere, which will contribute to ionosphere research and forecasting applications.

scholarly journals Application of Fengyun 3-C GNSS occulation sounder for assessing global ionospheric response to magnetic storm event

2016 ◽  
Author(s):  
Weihua Bai ◽  
Guojun Wang ◽  
Yueqiang Sun ◽  
Jiankui Shi ◽  
Xiangguang Meng ◽  
...  
Keyword(s):  
Magnetic Storm ◽  
Radio Occultation ◽  
Correlation Coefficients ◽  
Satellite System ◽  
Storm Event ◽  
Calibration Data ◽  
Long Term Stability ◽  
Negative Effect ◽  
Occultation Data ◽  
Global Navigation Satellite

Abstract. The rapid advancement of global navigation satellite system (GNSS) occultation technology in recent years has made it one of the most advanced space detection technologies of the 21st century. GNSS radio occultation has many advantages, including all-weather operation, global coverage, high vertical resolution, high precision, long-term stability, and self-calibration. Data products from GNSS occultation sounding can greatly enhance ionospheric observations and contribute to space weather monitoring, forecasting, modeling, and research. In this study, GNSS occultation sounder (GNOS) results from a radio occultation sounding payload aboard the Fengyun 3-C (FY3-C) satellite were compared with ground-based ionosonde observations. Correlation coefficients for peak electron density (NmF2) derived from GNOS Global Position System (GPS) and Beidou navigation system (BDS) products with ionosonde data were higher than 0.9, and standard deviations were less than 20 %. Global ionospheric effects of the strong magnetic storm event in March 2015 were analyzed using GNOS results supported by ionosonde observations. The magnetic storm caused a significant disturbance in NmF2 and hmF2 levels. Suppressed daytime and nighttime NmF2 levels indicated mainly negative storm conditions. In the zone of geomagnetic inclination between 40–80 °, average NmF2 during the geomagnetic storm showed the same basic trends in GNOS measurements, and in observations from 17 ground-based ionosonde stations, and confirmed the negative effect of the event on the ionosphere. The analysis demonstrates the reliability of the GNSS radio occultation sounding instrument GNOS aboard the FY3-C satellite, and confirms the utility of ionosphere products from GNOS for statistical and event-specific ionospheric physical analyses. Future FY3 series satellites, and increasing numbers of Beidou navigation satellites, will provide increasing GNOS occultation data on the ionosphere, which will contribute to ionosphere research and forecasting applications.

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