GPS radio occultation with CHAMP: Atmospheric profiling utilizing the space‐based single difference technique

Wickert, Jens; Beyerle, G.; Hajj, G. A.; Schwieger, Volker; Reigber, Christoph

doi:10.1029/2001gl013982

Cited by 69 publications

(60 citation statements)

References 16 publications

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“…Regarding the excess phase processing, a single-difference method removes the LEO satellite 10 clock offset by the difference between the GNSS occultation satellite and its GNSS reference satellite (Wickert et al, 2002). Comparing with the original double-difference method (Ware et al, 1996;Rocken et al, 1997), it uses the solved GNSS satellite clock offset estimates instead of further differencing between the GNSS satellites and a GNSS ground station, hence single-difference method can minimize the effects of ground data error sources during the 15 GPS clock offset estimation process Schreiner et al, 2010).…”

Section: Fy-3c Gnos Developed By National Space Science Center/chinementioning

confidence: 99%

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Evaluation of atmospheric profiles derived from single- and zero-difference excess phase processing of BeiDou System radio occultation data of the FY-3C GNOS mission

Bai¹,

Liu²,

Meng³

et al. 2017

Preprint

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The Global Navigation Satellite System (GNSS) Occultation Sounder (GNOS) is one of the 20 new generation payloads onboard the Chinese FengYun 3 (FY-3) series of operational meteorological satellites for sounding the Earth's neutral atmosphere and ionosphere. GNOS was designed for acquiring setting and rising radio occultation (RO) data by using GNSS signals from both the Chinese BeiDou System (BDS) and the U.S. Global Positioning System (GPS). An ultra-stable oscillator with 1-sec stability (Allan deviation) at the level of 10 -12 was 25 installed on FY-3C GNOS, thus both zero-difference and single-difference excess phase processing methods should be feasible for FY-3C GNOS observations. In this study we focus on evaluating zero-difference processing of BDS RO data vs. single-difference processing, in satellites. We used a 3-month set of GNOS BDS RO data (October to December 2013) for the evaluation and compared atmospheric bending angle and refractivity profiles, derived from 5 single-and zero-difference excess phase data, against co-located profiles from ECMWF (European Centre for Medium-Range Weather Forecasts) analyses. We also compared against co-located refractivity profiles from radiosondes. The statistical evaluation against these reference data shows that the results from single-and zero-difference processing are consistent in both bias and standard deviation, clearly demonstrating the feasibility of zero-10 differencing for GNOS BDS RO observations. The average bias (and standard deviation) of the bending angle and refractivity profiles were found to be as small as about 0.05%-0.2% (and 0.7%-1.6%) over the upper troposphere and lower stratosphere, including for the GEO, IGSO, and MEO subsets. Zero-differencing was found to perform slightly better, as may be expected from its lower vulnerability to noise. The validation results establish that GNOS can 15 provide, on top of GPS RO profiles, accurate and precise BDS RO profiles both from singleand zero-difference processing. The GNOS observations by the series of FY-3 satellites will thus provide important contributions to numerical weather prediction and global climate change analysis.

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Section: Fy-3c Gnos Developed By National Space Science Center/chinementioning

confidence: 99%

“…The subsequent LEO satellite missions such as the CHAllenging Minisatellite Payload (CHAMP) (Wickert et al, 2001(Wickert et al, , 2002, the Constellation Observing System for Meteorology, 10…”

Section: Introductionmentioning

confidence: 99%

Evaluation of atmospheric profiles derived from single- and zero-difference excess phase processing of BeiDou System radio occultation data of the FY-3C GNOS mission

Bai¹,

Liu²,

Meng³

et al. 2017

Preprint

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“…Similar results were found by Hajj et al [2001] for individual profiles. Statistical comparisons of both processing methods are necessary to verify this result [Wickert et al, 2002]. …”

Section: Gps Clock Error Correctionmentioning

confidence: 99%

GPS radio occultation with CHAMP: First results and status of the experiment

Wickert

Schmidt

Marquardt

et al. 2002

International Association of Geodesy Symposia

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Abstract. The GPS (Global Positioning System) radio occultation experiment onboard the German CHAMP (CHAllenging Microsatellite payload) satellite was successfully started on February 11, 2001. By the end of July 2001 about 16,000 occultations were recorded. More than 80% of the measurements could be processed to derive vertical profiles of atmospheric temperature and specific humidity. Throughout the measurement period GPS anti-spoofing mode was enabled. On average, about 230 globally distributed occultations per day were recorded. Their distribution shows a characteristic latitudinal dependence with maximum occultation density at polar regions and minimum density in the equatorial region. A statistical comparison of dry temperature profiles, derived from CHAMP measurements, and corresponding meteorological analyses shows excellent agreement between 8 and 30 km altitude. For the Northern hemisphere the mean deviation is <0.5 K with a standard deviation of <1 K between 12 and 25 km.A single difference technique was applied to the data analysis. The temperature difference for an individual profile compared to the corresponding data, retrieved by double differencing, is <0.1 K below 20 km and <0.5 K below 35 km altitude.

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“…Tech. Discuss., https://doi.org/10.5194/amt-2017-385 Manuscript under review for journal Atmos. following GNSS RO missions such as the Challenging Mini-satellite Payload (CHAMP) (Wickert et al, 2001(Wickert et al, , 2002, the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) (Anthes et al, 2000(Anthes et al, , 2008Schreiner et al, 2007), the Gravity Recovery and Climate Experiment (GRACE) Wickert et al, 2005), and the Meteorological Operational (MetOp) satellites (Edwards and Pawlak, 2000;Luntama et al, 5 2008). These missions have demonstrated the unique properties of the GNSS RO technique, such as high vertical resolution, high accuracy, all-weather capability and global coverage (Ware et al, 1996;Gorbunov et al, 1996;Rocken et al, 1997;Leroy, 1997;Steiner et al, 1999), and long-term stability and consistency of different RO mission observations (Foelsche et al, , 2011.…”

Section: Introductionmentioning

confidence: 99%

The FengYun-3C radio occultation sounder GNOS: a review of the mission and its early results and science applications

Sun¹,

Bai²,

Liu³

et al. 2018

Preprint

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The Global Navigation Satellite System (GNSS) occultation sounder (GNOS) is one of the new generation payloads onboard the Chinese FengYun 3 (FY-3) series of operational meteorological satellites for sounding the Earth's neutral atmosphere and ionosphere. FY-3C GNOS, onboard the FY-3 satellite C launched in September 2013, was designed for acquiring setting and rising radio 5 occultation (RO) data by using GNSS signals from both the Chinese BeiDou System (BDS) and the U.S. Global Positioning System (GPS). So far, the GNOS measurements and atmospheric and ionospheric data products have been validated and evaluated and then been used for atmosphere and ionosphere related scientific applications. This paper reviews the FY-3C GNOS instrument, RO data processing, data quality evaluation, 10 and research applications. The reviewed data validation and application results demonstrate that the FY-3C GNOS mission can provide accurate and precise atmospheric and ionospheric GNSS (i.e., GPS and BDS) RO profiles for numerical weather prediction (NWP), global climate monitoring (GCM) and space weather research (SWR). The performance of the FY-3C GNOS product quality evaluation and scientific applications establishes confidence that the GNOS data 15 from the series of FY-3 satellites will provide important contributions to SWP, GCM and SWR scientific communities.

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GPS radio occultation with CHAMP: Atmospheric profiling utilizing the space‐based single difference technique

Cited by 69 publications

References 16 publications

Evaluation of atmospheric profiles derived from single- and zero-difference excess phase processing of BeiDou System radio occultation data of the FY-3C GNOS mission

Evaluation of atmospheric profiles derived from single- and zero-difference excess phase processing of BeiDou System radio occultation data of the FY-3C GNOS mission

GPS radio occultation with CHAMP: First results and status of the experiment

The FengYun-3C radio occultation sounder GNOS: a review of the mission and its early results and science applications

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