An Analysis Study of FORMOSAT-7/COSMIC-2 Radio Occultation Data in the Troposphere

Chen, Shu-Ya; Liu, Chian‐Yi; Huang, Ching Yuang; Hsu, Shen Cha; Li, Hsiu Wen; Lin, Peihua; Cheng, Jia Ping

doi:10.3390/rs13040717

Cited by 34 publications

(34 citation statements)

References 23 publications

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“…To study the sensitivity of the assimilation system to these refractivity differences, Equation 2 along with the corresponding tangent linear and adjoint codes, is implemented in WRFDA, as discussed in Appendix A. their results show that C2 data quality in terms of stability, precision, and accuracy is comparable to that from C1. Chen et al (2021) showed the high quality of C2 temperature and specific humidity profiles (wetPf2) obtained from a 1D-Var retrieval. Here we assess the C2 refractivity observations for an extended period (October 2019 to December 2020).…”

Section: Gnss Ro Techniquementioning

confidence: 92%

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Evaluation and Assimilation of the COSMIC‐2 Radio Occultation Constellation Observed Atmospheric Refractivity in the WRF Data Assimilation System

et al. 2021

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Numerical weather prediction (NWP) depends on accurate initial conditions. NWP model initial conditions are obtained by optimally combining the model forecast and the atmospheric observations from satellites and ground-based observations (Kalnay, 2003).Atmospheric refractivity, available from the global navigation satellite system (GNSS) radio occultation (RO) technique, is a relatively new sounding system that provides valuable information on the temperature and water vapor structure of the atmosphere (Anthes, 2011;Kursinski et al., 1997). Compared with many other atmospheric measurement techniques, RO has several advantages. These include vertical resolution as high as a few hundred meters (Zeng et al., 2019), and high accuracy and precision. RO data are minimally affected by aerosols, clouds, or precipitation, do not require calibration, and are free from instrument drift and satellite-to-satellite bias (

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Section: Gnss Ro Techniquementioning

confidence: 92%

“…Chen et al. (2021) showed the high quality of C2 temperature and specific humidity profiles (wetPf2) obtained from a 1D‐Var retrieval. Here we assess the C2 refractivity observations for an extended period (October 2019 to December 2020).…”

Section: Gnss Ro Techniquementioning

confidence: 99%

Evaluation and Assimilation of the COSMIC‐2 Radio Occultation Constellation Observed Atmospheric Refractivity in the WRF Data Assimilation System

et al. 2021

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“…Due to the proven significant influence of TEC on the quality of the received satellite signal, much attention has been focused on TEC prediction, e.g., by using artificial neural networks [31][32][33][34]. Another important field of study is radio occultation technique, which is used both for studying ionosphere, space weather, and neutral atmosphere [35,36]. The troposphere, on the other hand, is the lowest and the thinnest layer of the atmosphere.…”

Section: Research Problemmentioning

confidence: 99%

On the Correlation of Solar Activity and Troposphere on the GNSS/EGNOS Integrity. Fuzzy Logic Approach

Krzykowska-Piotrowska

Dudek

Wielgosz

et al. 2021

Energies

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There is a noticeable number of studies carried out on both the operational parameters of Global Navigation Satellite System (GNSS) and the satellite signal itself. Researchers look for, inter alia, proven sources of errors affecting the integrity of the satellite signal because this parameter determines the approval of the system’s operational use. It also seems of key importance that the atmospheric conditions, in any area of satellite signal usage, should not be underestimated due to their extensive impact. As the ionospheric refraction seriously limits the operational use of the satellite navigation signal, in this article, the authors attempted to quantify the effect of solar activity (expressed by sunspots) on the signal integrity using fuzzy logic. Fuzzy reasoning is used when information is inaccurate or incomplete and necessitates making decisions under conditions of uncertainty. Thanks to fuzzy sets, there are no obstacles to characterize the degree of intensity of a given phenomenon. In order to look at the problem more broadly, attention was also paid to the tropospheric conditions, and it was verified whether, against the background of cloudiness, precipitation, humidity, pressure and temperature, solar activity affects the integrity to the greatest extent. The integrity measurements from the EGNOS system (PRN120 and PRN126) collected at the monitoring station in Warsaw, Poland in 2014 were used.

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“…The FORMOsa SATellite mission-7/Constellation Observing System for the Meteorology, Ionosphere, and Climate mission-2 (FORMOSAT-7/COSMIC-2, hereafter FS7/C2), which is a follow-on mission of FORMOSAT-3/COSMIC (FS3/C), was launched on 25 June 2019, and it now can provide more than 5000 RO soundings per day within the ±45° latitudinal region. The FS7/C2 data provide not only a larger data amount but also penetrate farther to near the surface than the FS3/C data, and qualities of both data are comparable (e.g., [7][8][9]). For example, Ho et al [8] compared the FORMOSAT-7/COSMIC-2 RO data and the radiosonde observations, and the mean difference and standard deviation (STD) of the refractivity were about 0.34% and 1.84%, respectively.…”

Section: Introductionmentioning

confidence: 99%

Impact of Radio Occultation Data on the Prediction of Typhoon Haishen (2020) with WRFDA Hybrid Assimilation

2021

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FORMOSAT-7/COSMIC-2 (FS7/C2) satellite was successfully launched in June 2019. The satellite provides about 5000 radio occultation (RO) soundings daily over the tropical and partial subtropical regions. Such plentiful RO soundings with high accuracy and vertical resolution could be used to improve model initial analysis for typhoon prediction. In this study, assimilation experiments with and without the RO data were conducted with the WRFDA hybrid system for the prediction of Typhoon Haishen (2020). The experimental results show a remarkable improvement in typhoon track prediction with RO data assimilation, especially when using a nonlocal refractivity operator. Results in cycling DA and forecast are analyzed and verified for the RO data impact. Diagnostics of potential vorticity (PV) tendency budget helps explain the typhoon translation induced by different physical processes in the budget. The typhoon translation is essentially dominated by horizontal PV advection, but the track deviation can increase due to the vertical PV advection with opposite effects in the absence of RO data. Sensitivity experiments for different model initial times, physics schemes, and RO observation amounts show positive RO data impacts on typhoon prediction, mainly contributed from FS7. Complementary, an improved forecast of Typhoon Hagupit (2020) is also illustrated for the RO data impact.

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An Analysis Study of FORMOSAT-7/COSMIC-2 Radio Occultation Data in the Troposphere

Cited by 34 publications

References 23 publications

Evaluation and Assimilation of the COSMIC‐2 Radio Occultation Constellation Observed Atmospheric Refractivity in the WRF Data Assimilation System

Evaluation and Assimilation of the COSMIC‐2 Radio Occultation Constellation Observed Atmospheric Refractivity in the WRF Data Assimilation System

On the Correlation of Solar Activity and Troposphere on the GNSS/EGNOS Integrity. Fuzzy Logic Approach

Impact of Radio Occultation Data on the Prediction of Typhoon Haishen (2020) with WRFDA Hybrid Assimilation

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