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SDO/HMI Linedepth, 45-Second Data

(2011). SDO/HMI Linedepth, 45-Second Data. [Data set]. Stanford University. https://doi.org/10.48322/2q9m-hj09. Accessed on .

Note: Proper references, including or other formats, should include the "Accessed on date" to identify the version of the resource being cited in a given publication.

ResourceID
spase://NASA/NumericalData/SDO/HMI/Linedepth_Data/PT45S

Description
The HMI Linedepth refers to the difference in intensity between the "true" continuum and intensity at the core of the the Fe I absorption line at 6173.3 Å on the surface of the sun. HMI samples the Fe I absorption line at 6173.3 Å at six points. Assuming that the "pure" solar Fe I line profile is a Gaussian, and the HMI filter filter transmission profiles are delta functions, the first and second Fourier coefficients of the of the Fe I line can be calculated and an estimate of the Doppler Velocity can be made. An estimate (proxy) for the continuum intensity Ic is obtained by "reconstructing" the solar line from the estimates of the Doppler shift λo, the linewidth σ, and the linedepth Id. More details can be found at http://jsoc.stanford.edu/relevant_papers/observables.pdf.

Metadata Rights
CC0-1.0: Creative Commons Zero v1.0 Universal
Note
CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions. The actual data/software may be subject to a different license.

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Details

Version:2.7.1

NumericalData

ResourceID
spase://NASA/NumericalData/SDO/HMI/Linedepth_Data/PT45S
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
SDO/HMI Linedepth, 45-Second Data
DOI
https://doi.org/10.48322/2q9m-hj09
ReleaseDate
2026-07-21 12:07:10Z
RevisionHistory
RevisionEvent
ReleaseDate
2024-11-01 00:08:46Z
Note
Metadata created by SY
RevisionEvent
ReleaseDate
2024-11-18 00:08:46Z
Note
Added DOI by SY
RevisionEvent
ReleaseDate
2025-09-18 11:27:08Z
Note
Added ResourceType and NamingAuthority. Changed http to https in top-level schemaLocation attribute. Fixed version number separator in top-level schemaLocation attribute. Matched version number in schemaLocation attribute to updated value in Version tag. ZCB
RevisionEvent
ReleaseDate
2025-09-30 14:25:17Z
Note
Updated PublishedBy name to match ROR Registry. ZCB
RevisionEvent
ReleaseDate
2025-12-04 13:31:25Z
Note
Added MetadataRightsList. Updated to 2.7.1. ZCB
RevisionEvent
ReleaseDate
2026-06-26 13:27:54Z
Note
Add 'Z' to RevisionEvent:ReleaseDate(s), PublicationDate, TemporalDescription:TimeSpan:StartDate. ZCB
RevisionEvent
ReleaseDate
2026-07-21 12:07:10Z
Note
Added HelioData InformationURL. JWL
Description
The HMI Linedepth refers to the difference in intensity between the "true" continuum and intensity at the core of the the Fe I absorption line at 6173.3 Å on the surface of the sun. HMI samples the Fe I absorption line at 6173.3 Å at six points. Assuming that the "pure" solar Fe I line profile is a Gaussian, and the HMI filter filter transmission profiles are delta functions, the first and second Fourier coefficients of the of the Fe I line can be calculated and an estimate of the Doppler Velocity can be made. An estimate (proxy) for the continuum intensity Ic is obtained by "reconstructing" the solar line from the estimates of the Doppler shift λo, the linewidth σ, and the linedepth Id. More details can be found at http://jsoc.stanford.edu/relevant_papers/observables.pdf.
PublicationInfo
Authors
The HMI Consortium: Stanford University (USA); NASA Goddard Space Flight Center (USA); Lockheed Martin Solar and Astrophysics Laboratory (USA); National Center for Atmospheric Research (USA)
PublicationDate
2011-01-21 00:00:00Z
PublishedBy
Stanford University
Contacts
Role Person StartDate StopDate Note
1. PrincipalInvestigator spase://SMWG/Person/Philip.H.Scherrer
2. GeneralContact spase://SMWG/Person/Rick.Bogart

InformationURL
Name
The HMI website at Stanford
URL
http://hmi.stanford.edu/
InformationURL
Name
The SDO/HMI Instrument paper
URL
https://doi.org/10.1007/s11207-011-9834-2
InformationURL
Name
HelioData
URL
https://helio.data.nasa.gov/dataset/SDO_HMI_Linedepth_Data_PT45S
Description
The HelioData dataset page provides an overview of the dataset with access links, associated variables, and more.
AccessInformation
RepositoryID
spase://SMWG/Repository/Stanford/HMI-AIA.JSOC
Availability
Online
AccessRights
Open
AccessURL
Name
JSOC Data Center
URL
http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Ld_45s[2020-01-01T00:00:00/60m]
Style
Search
Description
Change the date and the time to find the HMI data.
AccessURL
Name
SDO/HMI Data Search via Virtual Solar Observatory
URL
https://sdac.virtualsolar.org/cgi/search?time=1&instrument=HMI&spectrum=1&version=current&build=1
Description
VSO path to JSOC-resident SDO HMI data files
Format
FITS
InstrumentIDs
spase://SMWG/Instrument/SDO/HMI
MeasurementType
ImageIntensity
TemporalDescription
TimeSpan
StartDate
2010-04-24 19:11:26Z
RelativeStopDate
-P3D
Cadence
PT45S
ObservedRegion
Sun
ObservedRegion
Sun.Photosphere
Parameter #1
Name
FITS Data Array
Description
Linedepth
Cadence
PT45S
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
HPC
Wave
WaveType
Photon
WaveQuantity
Intensity
WavelengthRange
Low
6173
High
6173
Units
angstrom
SpatialCoverage
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
HPC
Description
Array size: 4096x4096 Pixel Resolution: 0.504 arcsec
NASA Insignia
Contact SPDF: NASA-SPDF Feedback/Support
Responsible NASA Official: Lan Jian
Site Editor: Rita Johnson
SPDF ROR ID
SPDF re3data ID
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Last Updated: 2026-07-21