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  • equatorial electrojet  (2)
  • space physics  (2)
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  • 1
    Publication Date: 2023-01-21
    Description: The intensity of the equatorial electrojet (EEJ) shows temporal and spatial variability that is not yet fully understood nor accurately modeled. Atmospheric solar tides are among the main drivers of this variability but determining different tidal components and their respective time series is challenging. It requires good temporal and spatial coverage with observations, which, previously could only be achieved by accumulating data over many years. Here, we propose a new technique for modeling the EEJ based on principal component analysis (PCA) of a hybrid ground‐satellite geomagnetic data set. The proposed PCA‐based model (PCEEJ) represents the observed EEJ better than the climatological EEJM‐2 model, especially when there is good local time separation among the satellites involved. The amplitudes of various solar tidal modes are determined from PCEEJ based tidal equation fitting. This allows to evaluate interannual and intraannual changes of solar tidal signatures in the EEJ. On average, the obtained time series of migrating and nonmigrating tides agree with the average climatology available from earlier work. A comparison of tidal signatures in the EEJ with tides derived from neutral atmosphere temperature observations show a remarkable correlation for nonmigrating tides such as DE3, DE2, DE4, and SW4. The results indicate that it is possible to obtain a meaningful EEJ spectrum related to solar tides for a relatively short time interval of 70 days.
    Description: Key Points: A novel technique to model the equatorial electrojet (EEJ) based on the principal component analysis of a hybrid ground‐satellite data set. The new modeling matches observations better than the EEJM‐2 model, especially when the Swarm satellites have optimum local time coverage. Time series of migrating and nonmigrating tides amplitude in the EEJ are derived from 70‐day window.
    Description: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior http://dx.doi.org/10.13039/501100002322
    Description: Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659
    Description: Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro http://dx.doi.org/10.13039/501100004586
    Description: MEXT Japan Society for the Promotion of Science http://dx.doi.org/10.13039/501100001691
    Keywords: ddc:538.7 ; geomagnetism ; equatorial electrojet ; atmospheric tides
    Language: English
    Type: doc-type:article
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  • 2
    Publication Date: 2022-03-23
    Description: Abstract
    Description: This data publication includes the half-hourly Hp30 and ap30 indices as well as the hourly Hp60 and ap60 indices. All are unitless and collectively denoted as Hpo or Hpo index family. The dataset is based on near real-time geomagnetic observatory data provided by 13 contributing observatories. It is derived and distributed by GFZ German Research Centre for Geosciences. When using the Hpo index, please cite this data publication as well as the accompanying publication Matzka et al. (in prep), which serves as documentation of the Hpo index family. The dataset is organised in yearly files, which, for the current year, are updated on a monthly basis. Typically, during the second week of a month, the data for the previous month is appended to the current year's file. The files are in ASCII files and start with header lines marked with # (hash). The Hpo index was developed within the H2020 project SWAMI and is produced by Geomagnetic Observatory Niemegk, GFZ German Research Centre for Geosciences. It derives from the same 13 geomagnetic observatories that also contribute to the Kp index (Matzka et al., 2021). They are listed as contributors to this data publication. With the introduction of the DOI ‘https://doi.org/10.5880/Hpo.0001’, this DOI landing page and the associated FTP server linked to the DOI become the primary archive of Hpo (while the other established index distribution mechanisms at GFZ will be maintained in parallel). With the DOI, the dataset can grow with time, but a change of the data, once published, is not possible. If necessity arises in the future to correct already published values, then the corrected dataset will be published with a new DOI. Older DOIs and data sets will then still be available. For each DOI, an additional versioning mechanism will be available to document changes to the files such as header or format changes, which do not affect the integrity of the data. The DOI https://doi.org/10.5880/Hpo.0001 identifies the current version. A format description is provided in the data download folder.
    Description: Other
    Description: The dataset is organised in yearly files, which, for the current year, are updated on a monthly basis. Typically, during the second week of a month, the data for the previous month is calculated and appended to the current year's file, both for the definitive and nowcast version. While the definitive Kp (and derived indices) are calculated from K values provided by the contributing observatories, the nowcast Kp (and derived indices) are calculated at GFZ from observatory data provided by the contributing observatories. The data are distributed in ASCII files. All files start with 10 header lines, each starting with a number sign (#, hash) and containing DOI as well as license information. Note that leading zeroes are not shown, they are represented by blanks. Missing data would be represented by -1. For more information, please refer to the associated data description and Matzka et al. (in prep).
    Keywords: Kp ; Kp index ; ap index ; Ap index ; space weather ; space physics ; geomagnetism ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOMAGNETISM ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOMAGNETISM 〉 GEOMAGNETIC INDICES 〉 KP INDEX ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 AURORAE ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 GEOMAGNETIC INDICES ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 MAGNETIC FIELDS/MAGNETIC CURRENTS ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 MAGNETIC STORMS ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 SOLAR WIND
    Type: Dataset , Dataset
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  • 3
    Publication Date: 2022-05-09
    Description: Abstract
    Description: The data set contains hourly mean values (HMV) of the horizontal magnetic field component H as measured at the geomagnetic observatory Huancayo for 1935 to 1985. Huancayo (IAGA code HUA) is located close to the magnetic equator and is operated by Instituto Geofisico del Peru. The HMVs were taken from the World Data Centre Kyoto (WDC Kyoto) and existing data gaps (in total some 19 years from the 1960ies, 1970ies and 1980ies) were filled in by typing handwritten records of the HMV at GFZ. These handwritten records were monthly tables that were received as digital images from geomagnetic observatory Huancayo or that were received as microfilms from World Data Centre Boulder, Colorado. We also produced digital images of these microfilms. The values from the WDC Kyoto are definitive values; the monthly tables presumably also contain definitive values. Corrections to HUA HMVs from WDC Kyoto: There is a known error in the time stamping of the HUA HMVs prior to 1948 (before 1948 the data was reported in local time, rather than universal time). This error is corrected in the present dataset. Also, an attempt was made to correct for a jump in the HMV time series at this time. For further corrections, see Matzka et al, 2017. Please note that a dataset based on the data provided here will be submitted to the WDC Kyoto at a later stage and might undergo further modifications. The data file is in ASCII format and contains blank-separated first the year (YYYY), the month (MM), the day (DD) followed by the 24 HMVs of H (format HHHHH) in nanotesla (nT), starting with the HMV for 00 to 01 universal time.Geomagnetic observatories are described in e.g. Jankowski and Sucksdorf (1996).
    Keywords: Geomagnetic Observatory Huancayo ; hourly mean values ; magnetic equator ; equator ; equatorial electrojet ; ionosphere
    Language: English
    Type: Dataset , Dataset
    Format: 3335118 Bytes
    Format: 1 Files
    Format: text/plain
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  • 4
    Publication Date: 2022-05-13
    Description: Abstract
    Description: This data publication includes the half-hourly Hp30 and ap30 indices as well as the hourly Hp60 and ap60 indices, collectively denoted as Hpo. This dataset is based on near real-time geomagnetic observatory data provided by 13 contributing observatories. It is derived and distributed by GFZ German Research Centre for Geosciences. When using the Hpo index, please cite this data publication as well as the accompanying publication Yamazaki et al. (submitted), which serves as documentation of the Hpo. The dataset is organised in yearly files, which, for the current year, are updated on a monthly basis. Typically, during the second week of a month, the data for the previous month is appended to the current year's file. The files are in ASCII files and start with header lines marked with # (hash). The Hpo index was developed within the H2020 project SWAMI (grant agreement No 776287) and is produced by Geomagnetic Observatory Niemegk, GFZ German Research Centre for Geosciences. It derives from the same 13 geomagnetic observatories that also contribute to the Kp index (Matzka et al., 2021, https://doi.org/10.5880/Kp.0001). They are listed as contributors to this data publication. With the introduction of the DOI for the Hpo index (Matzka et al, 2021, https://doi.org/10.5880/Hpo.0001), this DOI landing page and the associated HTTPS server linked to the DOI become the primary archive of Hpo (while the other established index distribution mechanisms at GFZ will be maintained in parallel). With the DOI, the dataset can grow with time, but a change of the data, once published, is not possible. If necessity arises in the future to correct already published values, then the corrected dataset will be published with a new DOI. Older DOIs and data sets will then still be available. For each DOI, an additional versioning mechanism will be available to document changes to the files such as header or format changes, which do not affect the integrity of the data. The DOI https://doi.org/10.5880/Hpo.0002 identifies the current version. A format description and a version history are provided in the data download folder.
    Description: Other
    Description: Version history: 2022-03-26 ---------- Publication of Version Hpo.0002. This version replaces version Hpo.0001. The Hpo, like the Kp nowcast, is based on the FMI algorithm (see Matzka et al., 2021, https://doi.org/10.1029/2020SW002641) and goes through a rescaling procedure to be more similar to the definitive Kp values. The data in version Hpo.0001 from 2018 onwards suffered from a slight error in this rescaling algorithm, causing for example somewhat too few Hpo 0 values and somewhat too many Hpo 0.333 values. This error was corrected for version Hpo.0002. The values from 1995 to 2017 are identical for both versions. 2021-04-26 ---------- Publication of Version Hpo.0001
    Keywords: Hpo ; Hpo index ; Hp30 ; ap30 ; Hp60 ; ap60 ; Kp ; Kp index ; ap index ; geomagnetism ; space weather ; space physics ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOMAGNETISM ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOMAGNETISM 〉 GEOMAGNETIC INDICES 〉 KP INDEX ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 AURORAE ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 GEOMAGNETIC INDICES ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 MAGNETIC FIELDS/MAGNETIC CURRENTS ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 MAGNETIC STORMS ; EARTH SCIENCE 〉 SUN-EARTH INTERACTIONS 〉 IONOSPHERE/MAGNETOSPHERE DYNAMICS 〉 SOLAR WIND
    Type: Dataset , Dataset
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