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

2021 ◽  
Vol 13 (4) ◽  
pp. 717
Author(s):  
Shu-Ya Chen ◽  
Chian-Yi Liu ◽  
Ching-Yuang Huang ◽  
Shen-Cha Hsu ◽  
Hsiu-Wen Li ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Water Vapor Pressure ◽  
Processing System ◽  
Lower Troposphere ◽  
Ground Truth ◽  
Satellite System ◽  
Spatial Distance ◽  
Mean Differences ◽  
Environmental Prediction ◽  
Global Navigation Satellite

This study investigates the Global Navigation Satellite System (GNSS) radio occultation (RO) data from FORMOSAT-7/COSMIC-2 (FS7/C2), which provides considerably more and deeper profiles at lower latitudes than those from the former FORMOSAT-3/COSMIC (FS3/C). The statistical analysis of six-month RO data shows that the rate of penetration depth below 1 km height within ±45° latitudes can reach 80% for FS7/C2, significantly higher than 40% for FS3/C. For verification, FS7/C2 RO data are compared with the observations from chartered missions that provided aircraft dropsondes and on-board radiosondes, with closer observation times and distances from the oceanic RO occultation over the South China Sea and near a typhoon circulation region. The collocated comparisons indicate that FS7/C2 RO data are reliable, with small deviations from the ground-truth observations. The RO profiles are compared with collocated radiosondes, RO data from other missions, global analyses of ERA5 and National Centers for Environmental Prediction (NCEP) final (FNL), and satellite retrievals of NOAA Unique Combined Atmospheric Processing System (NCAPS). The comparisons exhibit consistent vertical variations, showing absolute mean differences and standard deviations of temperature profiles less than 0.5 °C and 1.5 °C, respectively, and deviations of water vapor pressure within 2 hPa in the lower troposphere. From the latitudinal distributions of mean difference and standard deviation (STD), the intertropical convergence zone (ITCZ) is evidentially shown in the comparisons, especially for the NUCAPS, which shows a larger deviation in moisture when compared to FS7/C2 RO data. The sensitivity of data collocation in time departure and spatial distance among different datasets are presented in this study as well.

scholarly journals Tropical cyclones vertical structure from GNSS radio occultation: an archive covering the period 2001–2018

2020 ◽  
Author(s):  
Elżbieta Lasota ◽  
Andrea K. Steiner ◽  
Gottfried Kirchengast ◽  
Riccardo Biondi
Keyword(s):  
Tropical Cyclones ◽  
Vertical Structure ◽  
Radio Occultation ◽  
Weather Conditions ◽  
Satellite System ◽  
Spatial Distance ◽  
Correct Prediction ◽  
Data Files ◽  
High Vertical Resolution ◽  
Global Navigation Satellite

Abstract. Tropical Cyclones (TC) are natural destructive phenomena, which affect wide tropical and subtropical areas every year. Although the correct prediction of their tracks and intensity has improved over recent years, the knowledge about their structure and development is still insufficient. The Global Navigation Satellite System (GNSS) Radio Occultation (RO) technique can provide a better understanding of the TC because it enables to probe the atmospheric vertical structure with high accuracy, high vertical resolution, and global coverage in any weather conditions. In this work, we create an archive of co-located TC best tracks and RO profiles covering the period 2001–2018 and providing a complete view of the storms since the pre-cyclone status to the cyclone disappearance. We collected 1822 TC best tracks from the International Best Track Archive for Climate Stewardship and co-located them with 48313 RO profiles from seven satellite missions processed by Wegener Center for Climate and Global Change. We provide information about location and intensity of the TC, RO vertical profiles co-located within 3 hours and 500 km from the TC eye centre, and exact information about temporal and spatial distance between the TC centre and the RO mean tangent point. A statistical analysis shows how the archive well covers all the ocean basins and all the intensity categories. We finally demonstrate the application of this dataset to investigate the vertical structure for one TC example case. All the data files, separately for each TC, are publicly available in NetCDF format at https://doi.org/10.25364/WEGC/TC-RO1.0:2020.1 (Lasota et al., 2020).

scholarly journals Assimilation of GNSS radio occultation observations in GRAPES

2014 ◽  
Vol 7 (11) ◽  
pp. 3935-3946 ◽  
Author(s):  
Y. Liu ◽  
J. Xue
Keyword(s):  
Radio Occultation ◽  
Satellite System ◽  
Observation Error ◽  
Data Quality Control ◽  
Forecast System ◽  
China Meteorological Administration ◽  
Environmental Prediction ◽  
Global Navigation Satellite ◽  
Impact Experiments ◽  
Positive Effect

Abstract. This paper reviews the development of the global navigation satellite system (GNSS) radio occultation (RO) observations assimilation in the Global/Regional Assimilation and PrEdiction System (GRAPES) of China Meteorological Administration, including the choice of data to assimilate, the data quality control, the observation operator, the tuning of observation error, and the results of the observation impact experiments. The results indicate that RO data have a significantly positive effect on analysis and forecast at all ranges in GRAPES, not only in the Southern Hemisphere where conventional observations are lacking but also in the Northern Hemisphere where data are rich. It is noted that a relatively simple assimilation and forecast system in which only the conventional and RO observation are assimilated still has analysis and forecast skill even after nine months integration, and the analysis difference between both hemispheres is gradually reduced with height when compared with NCEP (National Centers for Environmental Prediction) analyses. Finally, as a result of the new on-board payload of the Chinese FengYun-3 (FY-3) satellites, the research status of the RO of FY-3 satellites is also presented.

scholarly journals Tropical cyclones vertical structure from GNSS radio occultation: an archive covering the period 2001–2018

2020 ◽  
Vol 12 (4) ◽  
pp. 2679-2693
Author(s):  
Elżbieta Lasota ◽  
Andrea K. Steiner ◽  
Gottfried Kirchengast ◽  
Riccardo Biondi
Keyword(s):  
Tropical Cyclones ◽  
Vertical Structure ◽  
Radio Occultation ◽  
Weather Conditions ◽  
Satellite System ◽  
Spatial Distance ◽  
Correct Prediction ◽  
Data Files ◽  
High Vertical Resolution ◽  
Global Navigation Satellite

Abstract. Tropical cyclones (TC) are natural destructive phenomena, which affect wide tropical and subtropical areas every year. Although the correct prediction of their tracks and intensity has improved over recent years, the knowledge about their structure and development is still insufficient. The Global Navigation Satellite System (GNSS) radio occultation (RO) technique can provide a better understanding of the TC because it enables us to probe the atmospheric vertical structure with high accuracy, high vertical resolution and global coverage in any weather conditions. In this work, we create an archive of co-located TC best tracks and RO profiles covering the period 2001–2018 and providing a complete view of the storms since the pre-cyclone status to the cyclone disappearance. We collected 1822 TC best tracks from the International Best Track Archive for Climate Stewardship and co-located them with 48 313 RO profiles from seven satellite missions processed by the Wegener Center for Climate and Global Change. We provide information about location and intensity of the TC, RO vertical profiles co-located within 3 h and 500 km from the TC eye centre, and exact information about temporal and spatial distance between the TC centre and the RO mean tangent point. A statistical analysis shows how the archive covers all the ocean basins and all the intensity categories well. We finally demonstrate the application of this dataset to investigate the vertical structure for one TC example case. All the data files, separately for each TC, are publicly available in NetCDF format at https://doi.org/10.25364/WEGC/TC-RO1.0:2020.1 (Lasota et al., 2020).

scholarly journals Assessments of the Retrieval of Atmospheric Profiles from GNSS Radio Occultation Data in Moist Tropospheric Conditions Using Radiosonde Data

2020 ◽  
Vol 12 (17) ◽  
pp. 2717
Author(s):  
Ying Li ◽  
Yunbin Yuan ◽  
Xiaoming Wang
Keyword(s):  
Radio Occultation ◽  
Satellite System ◽  
Specific Humidity ◽  
Radiosonde Data ◽  
Temperature Profiles ◽  
Standard Deviations ◽  
Mean Differences ◽  
June July ◽  
Global Navigation Satellite ◽  
Humidity Profiles

The Global Navigation Satellite System (GNSS) Radio Occultation (RO) retrieved temperature and specific humidity profiles can be widely used for weather and climate studies in troposphere. However, some aspects, such as the influences of background data on these retrieved moist profiles have not been discussed yet. This research evaluates RO retrieved temperature and specific humidity profiles from Wegener Center for Climate and Global Change (WEGC), Radio Occultation Meteorology Satellite Application Facility (ROM SAF) and University Corporation for Atmospheric Research (UCAR) Boulder RO processing centers by comparing with measurements from 10 selected Integrated Global Radiosonde Archive (IGRA) radiosonde stations in different latitudinal bands over 2007 to 2010. The background profiles used for producing their moist profiles are also compared with radiosonde. We found that RO retrieved temperature profiles from all centers agree well with radiosonde. Mean differences at polar, mid-latitudinal and tropical stations are varying within ±0.2 K, ±0.5 K and from −1 to 0.2 K, respectively, with standard deviations varying from 1 to 2 K for most pressure levels. The differences between RO retrieved and their background temperature profiles for WEGC are varying within ±0.5 K at altitudes above 300 hPa, and the differences for ROM SAF are within ±0.2 K, and that for UCAR are within 0.5 K at altitudes below 300 hPa. Both RO retrieved and background specific humidity above 600 hPa are found to have large positive differences (up to 40%) against most radiosonde measurements. Discrepancies of moist profiles among the three centers are overall minor at altitudes above 300 hPa for temperature and at altitudes above 700 hPa for specific humidity. Specific humidity standard deviations are largest at tropical stations in June July August months. It is expected that the outcome of this research can help readers to understand the characteristics of moist products among centers.

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

2018 ◽  
Vol 11 (10) ◽  
pp. 5797-5811 ◽  
Author(s):  
Yueqiang Sun ◽  
Weihua Bai ◽  
Congliang Liu ◽  
Yan Liu ◽  
Qifei Du ◽  
...  
Keyword(s):  
Quality Evaluation ◽  
Radio Occultation ◽  
Global Climate ◽  
Weather Prediction ◽  
Satellite System ◽  
Navigation Satellite ◽  
Neutral Atmosphere ◽  
Scientific Applications ◽  
Early Results ◽  
Global Navigation Satellite

Abstract. The Global Navigation Satellite System (GNSS) Occultation Sounder (GNOS) is one of the new-generation payloads on board the Chinese FengYun 3 (FY-3) series of operational meteorological satellites for sounding the Earth's neutral atmosphere and ionosphere. FY-3C GNOS, on board the FY-3 series C satellite launched in September 2013, was designed to acquire setting and rising radio occultation (RO) data by using GNSS signals from both the Chinese BeiDou Navigation Satellite System (BDS) and the US 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, and preliminary research applications according to the state-of-the-art status of the FY-3C GNOS mission and related publications. 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 from the series of FY-3 satellites will provide important contributions to NWP, GCM, and SWR scientific communities.

scholarly journals Monitoring and Computation of the Volumes of Stockpiles of Bulk Material by Means of UAV Photogrammetric Surveying

2019 ◽  
Vol 11 (12) ◽  
pp. 1471 ◽  
Author(s):  
Grazia Tucci ◽  
Antonio Gebbia ◽  
Alessandro Conti ◽  
Lidia Fiorini ◽  
Claudio Lubello
Keyword(s):  
Bulk Material ◽  
Laser Scanner ◽  
Ground Truth ◽  
Point Clouds ◽  
3D Models ◽  
Satellite System ◽  
3D Data ◽  
Current Survey ◽  
Close Range ◽  
Global Navigation Satellite

The monitoring and metric assessment of piles of natural or man-made materials plays a fundamental role in the production and management processes of multiple activities. Over time, the monitoring techniques have undergone an evolution linked to the progress of measure and data processing techniques; starting from classic topography to global navigation satellite system (GNSS) technologies up to the current survey systems like laser scanner and close-range photogrammetry. Last-generation 3D data management software allow for the processing of increasingly truer high-resolution 3D models. This study shows the results of a test for the monitoring and computing of stockpile volumes of material coming from the differentiated waste collection inserted in the recycling chain, performed by means of an unmanned aerial vehicle (UAV) photogrammetric survey and the generation of 3D models starting from point clouds. The test was carried out with two UAV flight sessions, with vertical and oblique camera configurations, and using a terrestrial laser scanner for measuring the ground control points and as ground truth for testing the two survey configurations. The computations of the volumes were carried out using two software and comparisons were made both with reference to the different survey configurations and to the computation software.

scholarly journals Preliminary validation of refractivity from a new radio occultation sounder GNOS/FY-3C

2015 ◽  
Vol 8 (9) ◽  
pp. 9009-9044 ◽  
Author(s):  
M. Liao ◽  
P. Zhang ◽  
G. L. Yang ◽  
Y. M. Bi ◽  
Y. Liu ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Radio Occultation ◽  
Weather Prediction ◽  
Satellite System ◽  
Navigation Satellite ◽  
Near Surface ◽  
Vertical Range ◽  
New Radio ◽  
Atmospheric Sounding ◽  
Global Navigation Satellite

Abstract. As a new member of space-based radio occultation sounder, the GNOS (Global Navigation Satellite System Occultation Sounder) mounted on FY-3C has been carrying out the atmospheric sounding since 23 September 2013. GNOS takes a daily measurement up to 800 times with GPS (Global Position System) and Chinese BDS (BeiDou navigation satellite) signals. The refractivity profiles from GNOS are compared with the co-located ECMWF (European Centre for Medium-Range Weather Forecasts) analyses in this paper. Bias and standard deviation have being calculated as the function of altitude. The mean bias is about 0.2 % from the near surface to 35 km. The average standard deviation is within 2 % while it is down to about 1 % in the range 5–30 km where best soundings are usually made. To evaluate the performance of GNOS, COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) and GRAS/METOP-A (GNSS Receiver for Atmospheric Sounding) data are also compared to ECMWF analyses as the reference. The results show that GNOS/FY-3C meets the requirements of the design well. It possesses a sounding capability similar to COSMIC and GRAS in the vertical range of 0–30 km, though it needs improvement in higher altitude. Generally, it provides a new data source for global NWP (numerical weather prediction) community.

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.

An Analysis of Alternatives for the COSMIC-2 Constellation in the Context of Global Observing System Simulation Experiments

2020 ◽  
Vol 35 (1) ◽  
pp. 51-66 ◽  
Author(s):  
L. Cucurull ◽  
M. J. Mueller
Keyword(s):  
System Simulation ◽  
Three Dimensional ◽  
Lower Troposphere ◽  
Weather Forecast ◽  
Satellite System ◽  
Forecast Skill ◽  
Added Value ◽  
Simulation Experiments ◽  
Global Navigation Satellite ◽  
The Impact

Abstract Observing system simulation experiments (OSSEs) were conducted to evaluate the potential impact of the six Global Navigation Satellite System (GNSS) radio occultation (RO) receiver satellites in equatorial orbit from the initially proposed Constellation Observing System for Meteorology, Ionosphere, and Climate-2 (COSMIC-2) mission, known as COSMIC-2A. Furthermore, the added value of the high-inclination component of the proposed mission was investigated by considering a few alternative architecture designs, including the originally proposed polar constellation of six satellites (COSMIC-2B), a constellation with a reduced number of RO receiving satellites, and a constellation of six satellites but with fewer observations in the lower troposphere. The 2015 year version of the operational three-dimensional ensemble–variational data assimilation system of the National Centers for Environment Prediction (NCEP) was used to run the OSSEs. Observations were simulated and assimilated using the same methodology and their errors assumed uncorrelated. The largest benefit from the assimilation of COSMIC-2A, with denser equatorial coverage, was to improve tropical winds, and its impact was found to be overall neutral in the extratropics. When soundings from the high-inclination orbit were assimilated in addition to COSMIC-2A, positive benefits were found globally, confirming that a high-inclination orbit constellation of RO receiving satellites is necessary to improve weather forecast skill globally. The largest impact from reducing COSMIC-2B from six to four satellites was to slightly degrade weather forecast skill in the Northern Hemisphere extratropics. The impact of degrading COSMIC-2B to the COSMIC level of accuracy, in terms of penetration into the lower troposphere, was mostly neutral.

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