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HMI Ring Diagrams
Data Product Descriptions
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hmi.rdMAI_fd30
Data Series Class:
Local Helioseismology Activity Indices
Creating Module:
maicalc
Input Data:
hmi.M_45s
Data Processing Status
The series only began to be populated as part of the Ring-Diagrams pipeline
beginning with CR 2195 (Sep 2017). It was retrospectively populated
working backward in time from CR 2195. Records for CR 2096–2194 were
fully populated as of 26 March. 2018.
Note that in the filling of records for times not populated as part of the
Ring-Diagrams pipeline, the minimum data coverage criterion of 70% is not
applied. Only intervals for which no suitable magnetograms exist will be
skipped. There are no such intervals to date for this series.
Values of the keyword CRLN_OBS describing the Carrington longitude
of the central meridian at the time of observation in the input magnetograms
hmi.M_45s (and the other corresponding observables, as well as those in the
720-sec cadence series) were erroneous, consistently too high by 0°.081894,
corresponding to a time offset of 1 AU/c and a plate location offset of
about 3 pixels. The correction for new data is pending as of
27 Apr 2026. This may introduce a detectable error
in the tracking rate. Processing of uncorrected data corrects for this
error beginning with
maicalc v 2.3.
Versions of creating module used to produce records in the data series:
- v 2.0 :
CR 2126:360 – 2199:030
- v 2.1 :
CR 2200:360 – 2228:120
- v 2.2 :
CR 2228:090 – 2234:030
- v 2.3 :
CR 2096:240 – 2099:030, 2235:360 – 2240:180
- v 2.4 :
CR 2100:360 – 2125:030, 2240:150 – 2249:030
- v 2.5 :
CR 2250:360 –
Note that records created with Version 2.0 originally lacked valid values
for several keywords: Samples, MeanMu, MeanPA, and COMMENT.
However, values for the first three of these have been subsequently set by
an independent module using the same algorithm, data, and parameters.
Because the MAI is a linear fit at the target time of the several means of
|Bz| at the sample times, it can potentially be negative,
especially if all available values are on one side of the target time. This
“feature” was addressed in Version 2.1, replacing a negative
extrapolated or interpolated value at the target time with a simple mean.
There are no records in this series with negative values of MAI.
The following records have been subsequently reprocessed and exist in multiple
versions in the DRMS database:
- [2202][270] : 69 records, originally processed 2018.05.17,
reprocessed 2018.06.20
- [2202][210] : 69 records, originally processed 2018.05.17,
reprocessed 2018.06.25
- [2202][180] : 69 records, originally processed 2018.05.17,
reprocessed 2018.06.27
- [2203][270] : 69 records, originally processed 2018.05.17,
reprocessed 2018.06.28
- [2204][270] : 69 records, originally processed 2018.06.13,
reprocessed 2018.07.07
- [2204][240] : 69 records, originally processed 2018.06.14,
reprocessed 2018.07.09
- [2226][180] : 69 records, originally processed 2020.02.01,
reprocessed 2020.02.03
All data records originally produced with versions 2.0–2.2 of
maicalc have been
mirrored to the data series
hmi.rdMAI_fd30_reproc. Most of those that were subsequently
reprocessed with version 2.3 or higher have been removed from this series
and exist only in the mirrored series.
The following subsequently reprocessed records have also been removed: