Table 3 Summary of all modelled sources with relevant parameters and prior information values
From: Sequential modelling of the Earth’s core magnetic field
Source | \(L_i\), \(L_a\) | Time scale | Prior | Nb. of par. | Coef. |
|---|---|---|---|---|---|
Static core field | 1, 18 | \({\tilde{\tau }}_{\ell }^c = 415/\ell \; \text {year}\) | \({\begin{array}{l} R = {3000}\,{\mathrm{km}} \\ S = {2\cdot 10^9}\,\mathrm {nT^2} \end{array}}\) | 360 | \({}^{\mathrm {C}}{g}_{\ell }^m\) |
Core SV | 1, 18 | \({\tilde{\tau }}_\ell ^{sv} = {11}\,{\mathrm{year}}\) | \({\begin{array}{l} R = {3500}\,{\mathrm{km}} \\ S = {1.5\cdot 10^4}\,\mathrm {(nT/year)^2} \end{array}}\) | 360 | \({}^{\mathrm {C}}{\dot{g}}_{\ell }^m\) |
Lithospheric field | 15, 30 | \(\tau ^{lt} = {10^6}\,{\mathrm{year}}\) | \({\begin{array}{l} R = {6280}\,{\mathrm{km}} \\ S = {2.7\cdot 10^{-2}}\,\mathrm {nT^2} \end{array}}\) | 736 | \({}^{\mathrm {L}}{g}_{\ell }^m\) |
Induced field | 1, 6 | \(\tau ^{I} < \Delta t\) | – | 48 | \({}^{\mathrm {I}}{g}_{\ell }^m\) |
Induced field variation | 1, 6 | \(\tau ^{\partial _t I} < \Delta t\) | – | 48 | \({}^{\mathrm {I}}{\dot{g}_{\ell }^m}\) |
GSM ext. field | 1, 3 | \(\tau ^{\text {GSM}} < \Delta t\) | \({\begin{array}{c} R = 1.6 \cdot 10^4 \, \mathrm {km} \\ S = {5.4\cdot 10^3}\,\mathrm {nT^2} \end{array}}\) | 15 | \({}^{{\mathrm {G}}}{q_\ell ^m}\) |
SM ext. field | 1, 3 | \(\tau ^{\text{SM}} < \Delta t\) | \({\begin{array}{l} R = {6900}\,{\mathrm{km}} \\ S = {3.56}\, \mathrm {nT^2} \end{array}}\) | 15 | \({}^{{\mathrm {S}}}{q_\ell ^m}\) |
\(\mathrm {I}_{\text{st}}\) indexed field | 1, 3 | \(\tau ^{\text{Ist}} < \Delta t\) | \({\begin{array}{l} R = {2537}\,{\mathrm{km}} \\ S = 1.0 \end{array}}\) | 15 | \({}^{{\mathrm {I_{\text{st}}}}}{g_\ell ^m}\) |
\(\mathrm {E}_{\text{st}}\) indexed field | 1, 3 | \(\tau ^{\text{Est}} < \Delta t\) | \({\begin{array}{l} R = 1.6 \cdot 10^4 \, \mathrm {km} \\ S = {5.4} \end{array}}\) | 15 | \({}^{{\mathrm {E_{\text{st}}}}}{q_\ell ^m}\) |
\(B^{\mathrm {IMF}}_y\) indexed field | 1, 3 | \(\tau ^{\text{IMF} }< \Delta t\) | \({\begin{array}{l} R = {6900}\,{\mathrm{km}} \\ S = {0.1} \end{array}}\) | 15 | \({}^{{\mathrm {I}}}{q_\ell ^m}\) |
Obs. offset | Non SH | \(\tau ^{lt} = {10^6}\,{\mathrm{year}}\) | – | \(3 \times 200\) | \({{\mathbf {O}}}_i\) |