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HMI Ring Diagrams
Pipeline Module Specifications
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maicalc
Module Version
1.0 10 III 2016
General Description
maicalc takes as its input a dataset of records representing solar
magnetograms during a selected interval, and produces as its output
the values of the Magnetic Activity Index ( MAI) appropriate for a
selected set of target locations as they would be mapped and tracked
by mtrack for the duration of the input data interval and apodized by
pspec3. The MAI values may be used as a set of input parameter values
to mtrack, and will be used to set appropriate keyword values in its
output data records. Also writes an output file containing values at
grid points of integrated values of Bz as well as |Bz| and the
time derivatives of both.
Status
This version has been superseded by Version 1.1
Not included in any JSOC release
In use for ring-diagram pipelines 2016.03.10 – 2016.09.09 ?
This version supersedes Version 0.9
The source code and Makefile is in ~rick/hmi/rings/src/versions/maicalc
Usage
maicalc [-nrv] ds= DataDescriptor
[param= val ...]
Flags
-n turn off tracking, just correct for any observer drift
in the latitudinal direction
-r turn off spatial apodization
-v run verbose
Parameters
ds either the name of an input data set (record selection)
or the name of an input data series; in the latter case,
tmid and length parameters must also be supplied.
Default: mdi.fd_M_96m_lev18
cr The Carrington rotation number at the target midpoint
of the analysis interval. Default: current value.
cl The Carrington longitude of central meridian at the target
midpoint of the tracking interval. Default: current value.
interval The length of the analysis interval, in Carrington degrees.
Default: 15.0
rec_step The sampling step, in units of the input record steps.
Default: 64
scale The scale of the mapped region(s) at map center, in
heliographic degrees per pixel. Default: 0.04
extent Extent of the integrating analysis region(s), in
heliographic degrees. Default: 15.36
lat An array of heliographic latitudes (in degrees) of the
centers of regions at the midpoint of the tracking.
Default: [0.0] (If there is only one target,
the enclosing characters, which may be brackets, braces, or
parentheses, may be omitted. Target values are separated by
commas.) If there are more lon values than lat values,
the final lat value is replicated.
lon An array of heliographic longitudes (in degrees) of the
centers of regions at the midpoint of the tracking.
Default: [0.0] If there are more lat values than lon
values, the final lon value is replicated. Note that
the longitudes are Carrington, not Stonyhurst.
mask_in The inner edge for a (1-r^2) apodization to be applied
to the mapped regions; Default: 0.9765625
mask_ex The outer edge for a (1-r^2) apodization to be applied
to the mapped regions; Default: 1.0
floor The "noise" floor below which data values are ignored for
the sake of integration (gauss); Default: 50.0
file The output file name for diagnostics, if any.
Default: unspecified
clon_key The key name to be used for the key value representing the
observer Carrington longitude at the time of observation in
the input data series; Default: CRLN_OBS
clat_key The key name to be used for the key value representing the
observer heliographic latitude at the time of observation in
the input data series; Default: CRLT_OBS
crot_key The key name to be used for the key value representing the
Carrington rotation number appropriate to the observer
central meridian at the time of observation in the input
data series; Default: CAR_ROT
rsun_key The key name to be used for the image semi-diameter in
pixels in the input data series; Default: R_SUN
apsd_key The key name to be used for the solar semi-diameter in
arcsec in the input data series; Default: RSUN_OBS
dsun_key The key name to be used for the sun-observer distance in
meters (to be used in conjunction with rsun_key in default
of a keyword for apsd_key; Default: DSUN_OBS
Input Data series class:
time series of solar magnetogram data
Sample input series:
mdi.fd_M_96m_lev18
Comments:
If tracking is turned off, the location of the target region will be
appropriate for the midpoint of the tracking interval. For example, if
the target interval ranges from central meridian longitudes 190–170
and a target region is at Carrington longitude 150, the Stonyhurst
longitude of the target would remain at 30° east for the duration of
the analysis interval.
Sample command:
maicalc ds= hmi.M_45s cr= 2100 cl= 180.0 \
scale= 0.04 extent= 30.72 interval= 30 \
lat= "{-60.0, -60.0, -45.0, -45.0, -30.0, -30.0, -15.0, -15.0, \
+00.0, +15.0, +15.0, +30.0, +30.0, +45.0, +45.0, +60.0, +60.0}" \
lon= "{120.0, 240.0, 135.0, 225.0, 150.0, 210.0, 165.0, 195.0, \
180.0, 195.0, 165.0, 210.0, 150.0, 225.0, 135.0, 240.0, 120.0}"
Significant changes from Previous Version
none — only changes were cleanup, more complete error checking,
and ensuring proper return status
Bugs in current version
There is no option for tracking at rates other than the Carrington rate
(or not at all).
There is no option for mapping using a projection other than the Lambert
azimuthal equivalent projection.
Selection of input data records as a DRMS DataSet name is not supported;
the ds parameter must be a DataSeries name, and values for the cr, cl,
and interval parameters must be supplied
Calculation of a Carrington rotation interval corresponding to the
requested time interval is based on a crude approximation of the synodic
rate as 13°.20/d — it actually varies by ±0°.03/d (for Earth) from that
value. But it is unnecessary, the input data should be selected based
directly on the time interval.
The default values are appropriate for the MDI ring-diagrams SSW ("densepack")
analysis. In any case, the algorithm for calculating the MAI will doubtless
need to be modified for use with HMI (or other) magnetograms.