Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO
Abstract Electric currents flowing in the terrestrial ionosphere have conventionally been diagnosed by low-earth-orbit (LEO) satellites equipped with science-grade magnetometers and long booms on magnetically clean satellites. In recent years, there are a variety of endeavors to incorporate platform...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-10-01
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| Series: | Earth, Planets and Space |
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| Online Access: | http://link.springer.com/article/10.1186/s40623-020-01274-3 |
| _version_ | 1818681848501370880 |
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| author | Jaeheung Park Claudia Stolle Yosuke Yamazaki Jan Rauberg Ingo Michaelis Nils Olsen |
| author_facet | Jaeheung Park Claudia Stolle Yosuke Yamazaki Jan Rauberg Ingo Michaelis Nils Olsen |
| author_sort | Jaeheung Park |
| collection | DOAJ |
| description | Abstract Electric currents flowing in the terrestrial ionosphere have conventionally been diagnosed by low-earth-orbit (LEO) satellites equipped with science-grade magnetometers and long booms on magnetically clean satellites. In recent years, there are a variety of endeavors to incorporate platform magnetometers, which are initially designed for navigation purposes, to study ionospheric currents. Because of the suboptimal resolution and significant noise of the platform magnetometers, however, most of the studies were confined to high-latitude auroral regions, where magnetic field deflections from ionospheric currents easily exceed 100 nT. This study aims to demonstrate the possibility of diagnosing weak low-/mid-latitude ionospheric currents based on platform magnetometers. We use navigation magnetometer data from two satellites, CryoSat-2 and the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO), both of which have been intensively calibrated based on housekeeping data and a high-precision geomagnetic field model. Analyses based on 8 years of CryoSat-2 data as well as ~ 1.5 years of GRACE-FO data reproduce well-known climatology of inter-hemispheric field-aligned currents (IHFACs), as reported by previous satellite missions dedicated to precise magnetic observations. Also, our results show that C-shaped structures appearing in noontime IHFAC distributions conform to the shape of the South Atlantic Anomaly. The F-region dynamo currents are only partially identified in the platform magnetometer data, possibly because the currents are weaker than IHFACs in general and depend significantly on altitude and solar activity. Still, this study evidences noontime F-region dynamo currents at the highest altitude (717 km) ever reported. We expect that further data accumulation from continuously operating missions may reveal the dynamo currents more clearly during the next solar maximum. |
| first_indexed | 2024-12-17T10:09:28Z |
| format | Article |
| id | doaj.art-9fed0351975540c8903d59d50406b29e |
| institution | Directory Open Access Journal |
| issn | 1880-5981 |
| language | English |
| last_indexed | 2024-12-17T10:09:28Z |
| publishDate | 2020-10-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Earth, Planets and Space |
| spelling | doaj.art-9fed0351975540c8903d59d50406b29e2022-12-21T21:53:05ZengSpringerOpenEarth, Planets and Space1880-59812020-10-0172111810.1186/s40623-020-01274-3Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FOJaeheung Park0Claudia Stolle1Yosuke Yamazaki2Jan Rauberg3Ingo Michaelis4Nils Olsen5Space Science Division, Korea Astronomy and Space Science InstituteGFZ-German Research Centre for GeosciencesGFZ-German Research Centre for GeosciencesGFZ-German Research Centre for GeosciencesGFZ-German Research Centre for GeosciencesDTU Space, National Space Institute, Technical University of DenmarkAbstract Electric currents flowing in the terrestrial ionosphere have conventionally been diagnosed by low-earth-orbit (LEO) satellites equipped with science-grade magnetometers and long booms on magnetically clean satellites. In recent years, there are a variety of endeavors to incorporate platform magnetometers, which are initially designed for navigation purposes, to study ionospheric currents. Because of the suboptimal resolution and significant noise of the platform magnetometers, however, most of the studies were confined to high-latitude auroral regions, where magnetic field deflections from ionospheric currents easily exceed 100 nT. This study aims to demonstrate the possibility of diagnosing weak low-/mid-latitude ionospheric currents based on platform magnetometers. We use navigation magnetometer data from two satellites, CryoSat-2 and the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO), both of which have been intensively calibrated based on housekeeping data and a high-precision geomagnetic field model. Analyses based on 8 years of CryoSat-2 data as well as ~ 1.5 years of GRACE-FO data reproduce well-known climatology of inter-hemispheric field-aligned currents (IHFACs), as reported by previous satellite missions dedicated to precise magnetic observations. Also, our results show that C-shaped structures appearing in noontime IHFAC distributions conform to the shape of the South Atlantic Anomaly. The F-region dynamo currents are only partially identified in the platform magnetometer data, possibly because the currents are weaker than IHFACs in general and depend significantly on altitude and solar activity. Still, this study evidences noontime F-region dynamo currents at the highest altitude (717 km) ever reported. We expect that further data accumulation from continuously operating missions may reveal the dynamo currents more clearly during the next solar maximum.http://link.springer.com/article/10.1186/s40623-020-01274-3Platform magnetometersCryoSat-2GRACE-FOInter-hemispheric field-aligned currentsF-region dynamo currents |
| spellingShingle | Jaeheung Park Claudia Stolle Yosuke Yamazaki Jan Rauberg Ingo Michaelis Nils Olsen Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO Earth, Planets and Space Platform magnetometers CryoSat-2 GRACE-FO Inter-hemispheric field-aligned currents F-region dynamo currents |
| title | Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO |
| title_full | Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO |
| title_fullStr | Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO |
| title_full_unstemmed | Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO |
| title_short | Diagnosing low-/mid-latitude ionospheric currents using platform magnetometers: CryoSat-2 and GRACE-FO |
| title_sort | diagnosing low mid latitude ionospheric currents using platform magnetometers cryosat 2 and grace fo |
| topic | Platform magnetometers CryoSat-2 GRACE-FO Inter-hemispheric field-aligned currents F-region dynamo currents |
| url | http://link.springer.com/article/10.1186/s40623-020-01274-3 |
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