Prospects of the EPS GRAS Mission For Operational Atmospheric Applications

Luntama, Juha-Pekka; Kirchengast, Gottfried; Borsche, Michael; Foelsche, Ulrich; Steiner, Andrea; Healy, S. B.; Engeln, Axel von; O'Clerigh, Eoin; Marquardt, Christian

doi:10.1175/2008bams2399.1

Cited by 105 publications

(108 citation statements)

References 44 publications

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“…As described by Kirchengast and Schweitzer (2011), the LMIO method can be considered as a next generation of the well established and successful GNSS-LEO radio occultation (GRO) method (Ware et al, 1996;Kursinski et al, 1997;Steiner et al, 2001;Anthes et al, 2008;Luntama et al, 2008;Steiner et al, 2009;Ho et al, 2009). LMIO and GRO share the occultation measurement principle (Phinney and Anderson, 1968; and the use of highly coherent and stable inter-satellite signals, and therefore the potential of providing accurate, long-term, consistent benchmark data with high vertical resolution and global coverage.…”

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confidence: 99%

Greenhouse gas profiling by infrared-laser and microwave occultation: retrieval algorithm and demonstration results from end-to-end simulations

2011

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Abstract. Measuring greenhouse gas (GHG) profiles with global coverage and high accuracy and vertical resolution in the upper troposphere and lower stratosphere (UTLS) is key for improved monitoring of GHG concentrations in the free atmosphere. In this respect a new satellite mission concept adding an infrared-laser part to the already well studied microwave occultation technique exploits the joint propagation of infrared-laser and microwave signals between Low Earth Orbit (LEO) satellites. This synergetic combination, referred to as LEO-LEO microwave and infrared-laser occultation (LMIO) method, enables to retrieve thermodynamic profiles (pressure, temperature, humidity) and accurate altitude levels from the microwave signals and GHG profiles from the simultaneously measured infrared-laser signals. However, due to the novelty of the LMIO method, a retrieval algorithm for GHG profiling is not yet available. Here we introduce such an algorithm for retrieving GHGs from LEO-LEO infraredlaser occultation (LIO) data, applied as a second step after retrieving thermodynamic profiles from LEO-LEO microwave occultation (LMO) data. We thoroughly describe the LIO retrieval algorithm and unveil the synergy with the LMOretrieved pressure, temperature, and altitude information. We furthermore demonstrate the effective independence of the GHG retrieval results from background (a priori) information in discussing demonstration results from LMIO end-toend simulations for a representative set of GHG profiles, including carbon dioxide (CO 2 ), water vapor (H 2 O), methane (CH 4 ), and ozone (O 3 ). The GHGs except for ozone are well Correspondence to: V. Proschek (veronika.proschek@uni-graz.at) retrieved throughout the UTLS, while ozone is well retrieved from about 10 km to 15 km upwards, since the ozone layer resides in the lower stratosphere. The GHG retrieval errors are generally smaller than 1 % to 3 % r.m.s., at a vertical resolution of about 1 km. The retrieved profiles also appear unbiased, which points to the climate benchmarking capability of the LMIO method. This performance, found here for clear-air atmospheric conditions, is unprecedented for vertical profiling of GHGs in the free atmosphere and encouraging for future LMIO implementation. Subsequent work will examine GHG retrievals in cloudy air, addressing retrieval performance when scanning through intermittent upper tropospheric cloudiness.

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confidence: 99%

Greenhouse gas profiling by infrared-laser and microwave occultation: retrieval algorithm and demonstration results from end-to-end simulations

2011

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“…Ionosphere and Climate (COSMIC) (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, 2008) satellites have further affirmed the long term stability and remarkable consistency (e.g., <0.2 -0.5 K in temperature) of RO observations from different RO 15 missions .…”

Section: Introductionmentioning

confidence: 94%

“…However, it requires the LEO receiver to be clocked by an ultra-stable oscillator that was so far available only for the GRACE and MetOp missions Luntama et al, 2008). The 25 FY-3 GNOS instrument is clocked by such an ultra-stable oscillator as well.…”

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

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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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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“…The subsequent low Earth Orbit (LEO) satellite missions such as the CHAllenging Minisatellite Payload (CHAMP; Wickert et al, 2001Wickert et al, , 2002, the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC; Anthes et al, 2000Anthes et al, , 2008Schreiner et al, 2007), the Gravity Recovery And Climate Experiment (GRACE; Beyerle et al, 2005;Wickert et al, 2005), and the Meteorological Operational (MetOp; Edwards and Pawlak, 2000;Luntama et al, 2008) satellites have further affirmed the long-term stability and remarkable consistency (e.g., < 0.2-0.5 K in temperature) of RO observations from different RO missions .…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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Abstract. 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. The 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 US Global Positioning System (GPS). An ultra-stable oscillator with 1 s stability (Allan deviation) at the level of 10 −12 was installed on the FY-3C GNOS, and thus both zero-difference and singledifference 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 order to investigate the zero-difference feasibility for this new instrument, which after its launch in September 2013 started to use BDS signals from five geostationary orbit (GEO) satellites, five inclined geosynchronous orbit (IGSO) satellites and four medium Earth orbit (MEO) 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 single-and zero-difference excess phase data, against co-located profiles from European Centre for Medium-Range Weather Forecasts (ECMWF) 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 reasonably consistent in both bias and standard deviation, clearly demonstrating the feasibility of zero differencing for GNOS BDS RO observations. The average bias (and standard deviation) of the bending angle and refractivity profiles were found to be about 0.05 to 0.2 % (and 0.7 to 1.6 %) over the upper troposphere and lower stratosphere. Zero differencing was found to perform slightly better, as may be expected from its lower vulnerability to noise. The validation results indicate that GNOS can provide, on top of GPS RO profiles, accurate and precise BDS RO profiles both from single-and zero-difference processing. The GNOS observations by the series of FY-3 satellites are thus expected to provide important contributions to numerical weather prediction and global climate change analysis.

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Prospects of the EPS GRAS Mission For Operational Atmospheric Applications

Abstract: Radio occultation receivers on board Europe's new polar orbiting satellites provide very high-quality observations of atmospheric characteristics for operational numerical weather forecasting and climate monitoring.

Cited by 105 publications

References 44 publications

Greenhouse gas profiling by infrared-laser and microwave occultation: retrieval algorithm and demonstration results from end-to-end simulations

Greenhouse gas profiling by infrared-laser and microwave occultation: retrieval algorithm and demonstration results from end-to-end simulations

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 radio occultation data from the FY-3C GNOS mission

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