Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system
FengYun-3C (FY-3C) is an operational polar-orbiting satellite carrying the new-generation microwave sounding instruments in China. This paper describes the assimilation of the FY-3C Microwave Temperature Sounder-2 (MWTS-2) radiances in the Global and Regional Assimilation and PrEdiction System (GRAP...
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ftcopernicus:oai:publications.copernicus.org:amt48416 2023-05-15T18:18:46+02:00 Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system Li, Juan Liu, Guiqing 2018-02-02 application/pdf https://doi.org/10.5194/amt-9-3095-2016 https://amt.copernicus.org/articles/9/3095/2016/ eng eng doi:10.5194/amt-9-3095-2016 https://amt.copernicus.org/articles/9/3095/2016/ eISSN: 1867-8548 Text 2018 ftcopernicus https://doi.org/10.5194/amt-9-3095-2016 2020-07-20T16:24:03Z FengYun-3C (FY-3C) is an operational polar-orbiting satellite carrying the new-generation microwave sounding instruments in China. This paper describes the assimilation of the FY-3C Microwave Temperature Sounder-2 (MWTS-2) radiances in the Global and Regional Assimilation and PrEdiction System (GRAPES) of China Meteorological Administration. A quality control (QC) procedure for the assimilation of MWTS-2 radiance is proposed. Extensive monitoring before assimilation shows that MWTS-2 observations exhibit a clear striping pattern. A technique combining principal component analysis (PCA) and ensemble empirical mode decomposition (EEMD) is applied to the observations to remove the striping noise. Cloudy field-of-views (FOVs) are identified by applying the Visible and InfrarRed Radiometer (VIRR) cloud fraction threshold of 76 %. Other QC steps are conducted in the follow order: (i) coastal FOVs are removed, (ii) eight outmost FOVs are not used, (iii) channel 5 data over sea ice and land are not used, (iv) channel 6 observations are not used if the terrain altitudes are higher than 500 m, and (v) outliers with large differences between observations and model simulations are removed. Approximately 83, 75, 40, and 40 % of the observations are removed by the proposed QC for channels 5–8, respectively. After QC, the global biases and standard deviations are reduced significantly. The assimilation of the MWTS-2 radiances shows a positive impact when the control experiment assimilates only conventional observations. The experiments also show that the analysis and forecast errors are slightly reduced when the striping noise is removed from the observations. The quality control scheme of extracting the striping noise may contribute to the analysis and forecast accuracy. The impact of MWTS-2 is neutral when the conventional data and other satellite data are all assimilated. Text Sea ice Copernicus Publications: E-Journals Atmospheric Measurement Techniques 9 7 3095 3113 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
FengYun-3C (FY-3C) is an operational polar-orbiting satellite carrying the new-generation microwave sounding instruments in China. This paper describes the assimilation of the FY-3C Microwave Temperature Sounder-2 (MWTS-2) radiances in the Global and Regional Assimilation and PrEdiction System (GRAPES) of China Meteorological Administration. A quality control (QC) procedure for the assimilation of MWTS-2 radiance is proposed. Extensive monitoring before assimilation shows that MWTS-2 observations exhibit a clear striping pattern. A technique combining principal component analysis (PCA) and ensemble empirical mode decomposition (EEMD) is applied to the observations to remove the striping noise. Cloudy field-of-views (FOVs) are identified by applying the Visible and InfrarRed Radiometer (VIRR) cloud fraction threshold of 76 %. Other QC steps are conducted in the follow order: (i) coastal FOVs are removed, (ii) eight outmost FOVs are not used, (iii) channel 5 data over sea ice and land are not used, (iv) channel 6 observations are not used if the terrain altitudes are higher than 500 m, and (v) outliers with large differences between observations and model simulations are removed. Approximately 83, 75, 40, and 40 % of the observations are removed by the proposed QC for channels 5–8, respectively. After QC, the global biases and standard deviations are reduced significantly. The assimilation of the MWTS-2 radiances shows a positive impact when the control experiment assimilates only conventional observations. The experiments also show that the analysis and forecast errors are slightly reduced when the striping noise is removed from the observations. The quality control scheme of extracting the striping noise may contribute to the analysis and forecast accuracy. The impact of MWTS-2 is neutral when the conventional data and other satellite data are all assimilated. |
format |
Text |
author |
Li, Juan Liu, Guiqing |
spellingShingle |
Li, Juan Liu, Guiqing Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system |
author_facet |
Li, Juan Liu, Guiqing |
author_sort |
Li, Juan |
title |
Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system |
title_short |
Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system |
title_full |
Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system |
title_fullStr |
Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system |
title_full_unstemmed |
Direct assimilation of Chinese FY-3C Microwave Temperature Sounder-2 radiances in the global GRAPES system |
title_sort |
direct assimilation of chinese fy-3c microwave temperature sounder-2 radiances in the global grapes system |
publishDate |
2018 |
url |
https://doi.org/10.5194/amt-9-3095-2016 https://amt.copernicus.org/articles/9/3095/2016/ |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 1867-8548 |
op_relation |
doi:10.5194/amt-9-3095-2016 https://amt.copernicus.org/articles/9/3095/2016/ |
op_doi |
https://doi.org/10.5194/amt-9-3095-2016 |
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Atmospheric Measurement Techniques |
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9 |
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7 |
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3095 |
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3113 |
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1766195456670433280 |