The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAM
Abstract With the development of the Global Navigation Satellite System (GNSS) and regional augmentation systems, the influence of the ionosphere on GNSS signals is becoming increasingly important. It is also of particular interest to retrieve the electron density distribution from GNSS observations...
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| Format: | Article |
| Language: | English |
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Wiley
2023-06-01
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| Series: | Space Weather |
| Online Access: | https://doi.org/10.1029/2022SW003378 |
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| author | L. Yuan M. M. Hoque Timothy Kodikara |
| author_facet | L. Yuan M. M. Hoque Timothy Kodikara |
| author_sort | L. Yuan |
| collection | DOAJ |
| description | Abstract With the development of the Global Navigation Satellite System (GNSS) and regional augmentation systems, the influence of the ionosphere on GNSS signals is becoming increasingly important. It is also of particular interest to retrieve the electron density distribution from GNSS observations. We have successfully developed a four‐dimensional variational assimilation scheme, the Neustrelitz Electron Density Assimilation Model (NEDAM), and verified NEDAM by a simulation study using a European ground‐based GNSS network. The performance of NEDAM is validated using two ionosondes and COSMIC‐1 radio occultation observations during the September 2017 geomagnetic storm period. The critical frequency of the F2 layer in NEDAM is much more accurate than that of a physics‐based model driven by observed geophysical indices or the Neustrelitz Electron Density Model (NEDM), when compared to data from two ionosondes. During the storm, the root mean square error of the F2‐layer critical frequency with respect to the two ionosondes is improved by 0.54 and 0.42 MHz, respectively. We also compare two co‐located electron density profiles from the COSMIC‐1 mission with NEDAM and NEDM. It is found that NEDAM is able to reconstruct well not only the peak density but also the peak density height, which is missing in the previous research. |
| format | Article |
| id | doaj-art-cd80a470a0ab46bf81f8d3d4b4fcc33e |
| institution | Kabale University |
| issn | 1542-7390 |
| language | English |
| publishDate | 2023-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Space Weather |
| spelling | doaj-art-cd80a470a0ab46bf81f8d3d4b4fcc33e2025-01-14T16:27:02ZengWileySpace Weather1542-73902023-06-01216n/an/a10.1029/2022SW003378The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAML. Yuan0M. M. Hoque1Timothy Kodikara2German Aerospace Center (DLR) Institute for Solar‐Terrestrial Physics Neustrelitz GermanyGerman Aerospace Center (DLR) Institute for Solar‐Terrestrial Physics Neustrelitz GermanyGerman Aerospace Center (DLR) Institute for Solar‐Terrestrial Physics Neustrelitz GermanyAbstract With the development of the Global Navigation Satellite System (GNSS) and regional augmentation systems, the influence of the ionosphere on GNSS signals is becoming increasingly important. It is also of particular interest to retrieve the electron density distribution from GNSS observations. We have successfully developed a four‐dimensional variational assimilation scheme, the Neustrelitz Electron Density Assimilation Model (NEDAM), and verified NEDAM by a simulation study using a European ground‐based GNSS network. The performance of NEDAM is validated using two ionosondes and COSMIC‐1 radio occultation observations during the September 2017 geomagnetic storm period. The critical frequency of the F2 layer in NEDAM is much more accurate than that of a physics‐based model driven by observed geophysical indices or the Neustrelitz Electron Density Model (NEDM), when compared to data from two ionosondes. During the storm, the root mean square error of the F2‐layer critical frequency with respect to the two ionosondes is improved by 0.54 and 0.42 MHz, respectively. We also compare two co‐located electron density profiles from the COSMIC‐1 mission with NEDAM and NEDM. It is found that NEDAM is able to reconstruct well not only the peak density but also the peak density height, which is missing in the previous research.https://doi.org/10.1029/2022SW003378 |
| spellingShingle | L. Yuan M. M. Hoque Timothy Kodikara The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAM Space Weather |
| title | The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAM |
| title_full | The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAM |
| title_fullStr | The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAM |
| title_full_unstemmed | The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAM |
| title_short | The Four‐Dimensional Variational Neustrelitz Electron Density Assimilation Model: NEDAM |
| title_sort | four dimensional variational neustrelitz electron density assimilation model nedam |
| url | https://doi.org/10.1029/2022SW003378 |
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