The production of data is done within the
WP2(Photosphere) of
SOTERIA (
SOlar-
TERrestrial
Investigations and
Archives) project supported by the
European Community's Seventh Framework Program (FP7/2007-2013 ) under
grant agreement No. 218816 (SP1-Cooperation/1 Nov 2008 - 31 Oct
2011). The primary aim is to cover the entire SOHO-era with
the most detailed data of sunspots, sunspot groups and photospheric
faculae derived from MDI (Michelson Doppler
Imager)
continuum images with a ~1 image/hour temporal resolution.
Data and Image Products: (All ftp)
The research
leading to these results has received
funding from the European Community's Seventh Framework Programme
(FP7/2007-2013) under grant agreement n° 218816.
Format of the SOHO/MDI - Debrecen
Sunspot Data
(SDD) catalogue:
The
same method is used as in the case of production of
Debrecen
Photoheliographic Data (DPD)
sunspot catalogue, and the software of the DPD has been suitably
modified in order to adapt to
SOHO/MDI full-disk continuum (Ic) images .
The SDD yields the position and area data of all observable sunspots on
an about hourly
basis (30 min =< t < day) of MDI observations as well as the
digitized images of sunspot groups.
The text files contain
the sunspot data (see
SDDformat.txt),
and
the images of the sunspot groups show the measured spots. The
full-disk facular data have the same format as full-disk sunspot data,
but umbral areas are obviously not measured for faculae, and the first
column of magnetic data contains the LOS magnetic field value at the
brightest pixel within the facular contour in the intensity image.
We use the Full Disk Continuum images (fd_Ic_01h) from the Hourly Data
Sets
(from High Rate Science) Level 1.8. In this data set there are
observations
with different time resolution (from one/day to one/min) in different
time intervals. In the latest years usually there is one Ic image per
hour
but not in every hours. To get a data set with a more or less regular
time
resolution that contains the most available images we have decided to
use one image/hour time resolution. The best available Ic image is
chosen
within the time interval (hour - 30 min, hour + 30 min) which is the
closest
to the center of the time interval. If there is no Ic image in a given
interval, the gap is filled with a Full Disk Continuum filtergram image
(fd_I0_01h) when it is available. The measured Ic and I0 images
are also published in our
FTP
archive in
the original form. File name
convention: I_yyyymmdd_hhmmss. During the measuring process the
selected
full disk intensity images are enlarged (3x), filtered, corrected for
limb darkening, and transformed to negative. If the P_ANGLE of
the image is 180 degree then the processed image is
rotated to the normal position, otherwise
the image preserves its original orientation.
The large amount of the available magnetograms allows for us
to
choose the magnetogram closest in time to the Ic image, and determine
the
magnetic field of the spots. Mean values of the line-of-sight magnetic
field are computed if Ic images and magnetograms are available within
50 min. The best available magnetograms closest in time to the
intensity images
are
chosen from the merged data sets of Full Disk Magnetograms of the
Hourly Data Sets (from High Rate Science) and Daily Data Sets (from Low
Rate
Science & Synoptic) Level 1.8 (fd_M_01h and fd_M_96m_01d). All the
magnetograms used in the catalogue and are available on-line. File
name
convention: M_yyyymmdd_hhmmss.
The set of images contains the Ic images with the nearest
magnetograms selected after using quality-filters and time
sequence criteria. If an hourly data is missing,
it means that there is no Ic observation within the given time
interval, or the available Ic observation is
not measurable (perfect), or there are no measurable Ic images and
magnetograms
available with less than
50 min time difference.
The full-disk version of the SDD catalogue
(fdSDD) is based on the same
hourly
time resolution MDI observations, but the spots are
numbered by the computer
program on the basis of their longitude and they is not assigned to
sunspot groups. In the fdSDD catalogue all
sunspots have their area, position
and magnetic field values similar to SDD sunspot group catalogue. In
this case the "g" raws are sums over the whole
disk, which have no
real physical meaning, but these raws are remained unchanged to
keep the format, and in this form they show the
excess of one of the
polarities of the line-of-sight magnetic field concentrated in spots.
The
previous
version of SDD was produced during the ESA-PECS
project entitled "
SOHO/VIRGO, MDI -
DPD catalogue studies" (2004-2007). The data (
oldSDD1996)
and
images (
old1996jpg)
for
1996
are still available as samples for the results of this project.
The whole set of data is reprocessed during the SOTERIA
project because the MDI
magnetograms were recalibrated at the end of 2008.
Contact person: T. Baranyi
(baranyi[at]tigris.unideb.hu)
Last modified: 2010-01-26
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Related sites:
MDI home page
Solar Feature
Catalogue
The Solar
and Heliospheric Observatory -- SOHO