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## SW_MMA_SHA_2C

Full product name

Timeseries of spherical harmonic expansion coefficients of the large-scale magnetospheric field from the comprehensive inversion chain

## Description

Timeseries of spherical harmonic expansion coefficients of the large-scale magnetospheric field from the comprehensive inversion chain

## Data Access

- Files
- HTTPS (Product files): https://swarm-diss.eo.esa.int/#swarm/Level2longterm/MMA
- FTP (Product files): ftp://swarm-diss.eo.esa.int/Level2longterm/MMA

- Web services

## Output variables

Name | Type | Dim | Unit | Contents |
---|---|---|---|---|

t_qs_1 | CDF_EPOCH | 1 | ms | Time instants of external Gauss coefficients q (cosine) and s (sine) |

qs_1 | CDF_DOUBLE | 1 | nT | External Gauss coefficients q (cosine) and s (sine) in dipole frame corresponding to time instants t_qs_1 |

dqs_1 | CDF_DOUBLE | 1 | nT | Formal error estimate for qs_1 |

nm_qs_1 | CDF_INT2 | 1 | - | First column: vector of spherical harmonic degrees of the coefficients qs_1. Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients q (cosine) while negative values denote coefficients s (sine) |

t_qs_2 | CDF_EPOCH | 1 | ms | Time instants of external Gauss coefficients q (cosine) and s (sine) |

qs_2 | CDF_DOUBLE | 2 | nT | External Gauss coefficients q (cosine) and s (sine) in dipole frame corresponding to time instants t_qs_2 |

dqs_2 | CDF_DOUBLE | 2 | nT | Formal error estimate for qs_2 |

nm_qs_2 | CDF_INT2 | 2 | - | First column: vector of spherical harmonic degrees of the coefficients qs_2.Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients q (cosine) while negative values denote coefficients s (sine) |

t_gh_1 | CDF_EPOCH | 1 | ms | Time instants of induced Gauss coefficients g (cosine) and h (sine) |

gh_1 | CDF_DOUBLE | 1 | nT | Internal induced Gauss coefficients g (cosine) and h (sine) in dipole frame |

dgh_1 | CDF_DOUBLE | 1 | nT | Formal error estimate for gh_1 |

nm_gh_1 | CDF_INT2 | 1 | - | First column: vector of spherical harmonic degrees of the coefficients gh_1.Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients g (cosine) while negative values denote coefficients h (sine) |

t_gh_2 | CDF_EPOCH | 1 | ms | Time instants of induced Gauss coefficients g (cosine) and h (sine) |

gh_2 | CDF_DOUBLE | 2 | nT | Internal induced Gauss coefficients g (cosine) and h (sine) in dipole frame |

dgh_2 | CDF_DOUBLE | 2 | nT | Formal error estimate for gh_2 |

nm_gh_2 | CDF_INT2 | 2 | - | First column: vector of spherical harmonic degrees of the coefficients gh_2.Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients g (cosine) while negative values denote coefficients h (sine) |

t_qual | CDF_EPOCH | 1 | ms | Time instants of quality information (rms, n_data, and q_flag). |

rms | CDF_DOUBLE | 2 | nT | Root-mean-square difference between models and input data (after processing to subtract non-magnetospheric sources) in dipole frame, for the time instants indicated by t_qualFirst column: RMS difference in radial direction. Second column: RMS difference in theta direction. Third column: RMS difference in phi direction. |

n_data | CDF_UINT2 | 2 | - | Number of data used at each time-instant from each satellite.First column: Number of data from SWARM A. Second column: Number of data from SWARM B. Third column: Number of data from SWARM C. |

## Details

Product identifier | MMA_SHA_2C |
---|---|

Definition | Spherical harmonic representation of the large scale magnetospheric field and of its induced counterpart |

Input data | MMA_SHAi2C, MMA_VAL_2_ |

Input time span | All available quiet time observations from the mission |

Spatial representation | Spherical Harmonics of degree and order at least 1 for the external field and of degree and order at least 5 for its Earth induced counterpart |

Time representation | Time series |

Units | nT |

Resolution | ≤ 1 pT |

Uncertainty | Refer to product quality report |

Quality indicator | Statistics of data misfit provided in the validation report |

Data volume | ~2 MB/year |

Output data | Time series of external and induced SH coefficients in dipole coordinate frame; root-mean-square differences between (processed) input data and models; number of data from each satellite used for each model; quality flag |

Output time span | Time span as input |

Update rate | First after 1 year, updated every year |

Latency | 1.5 months |

Notes |

## Related resources

Part of the CI (comprehensive inversion) chain, related to the "CM" model series, see e.g.:
Sabaka, T.J., Tøffner-Clausen, L., Olsen, N. et al. CM6: a comprehensive geomagnetic field model derived from both CHAMP and Swarm satellite observations. Earth Planets Space 72, 80 (2020). https://doi.org/10.1186/s40623-020-01210-5