Table 2.
Overview of the instrument comparisons.
| Comparison | Number of daily | Period [year.month.day] | Coverage (a) | FWHM(b) | Magnetogram | |
|---|---|---|---|---|---|---|
| magnetogram pairs | [arcsec] | noise threshold (c) [G] | ||||
| MDI(1)-SPM | 87 | 1996.04.23–1998.06.08 | 0.112 | 4.77 | MDI(1): 16.6 | SPM: 13.4 |
| MDI(2)-SPM | 182 | 1999.02.25–2003.09.05 | 0.110 | 4.44 | MDI(2): 23.1 | SPM: 15.8 |
| MDI(2)-VSM(1) | 385 | 2003.09.01–2009.11.20 | 0.169 | 5.44 | MDI(2): 18.8 | VSM(1): 19.3 |
| MDI(2)-VSM(2) | 104 | 2009.12.18–2011.04.11 | 0.217 | 6.34 | MDI(2): 14.9 | VSM(2): 13.7 |
| HMI-VSM(2) | 406 | 2010.05.01–2014.01.28 | 0.297 | 5.41 | HMI: 9.09 | VSM(2): 11.6 |
| HMI-VSM(3) | 490 | 2014.02.04–2017.10.20 | 0.362 | 6.04 | HMI: 10.6 | VSM(3): 14.0 |
| HMI-MDI(2) | 287 | 2010.04.30–2011.04.11 | 0.827 | 3.32 | HMI: 17.6 | MDI(2): 27.3 |
Notes.
The proportion of the period covered by the daily magnetogram pairs, i.e. the ratio of the number of pairs and the number of days between the first and last pairs.
The full width at half maximum (FWHM) of the Gaussian kernel applied to the MDI magnetograms in the comparison to SPM and VSM magnetograms, and to the HMI magnetograms in the comparison to VSM and MDI magnetograms (see Sect. 2.3).
The magnetogram signal threshold applied to the MDI(1) (first column) and SPM data (second column) in the MDI(1)-SPM comparison, and so on (see Sect. 2.4).
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.