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Data Access
SEE Data Products web page
TIMED SEE Level 4 XPS Modeled Solar Irradiance Data
var authors='Woods, Thomas N.';
document.write(authors);
(2025).
TIMED SEE Level 4 XPS Modeled Solar Irradiance Data.
[Data set].
Johns Hopkins University Applied Physics Laboratory.
https://doi.org/10.48322/v1q7-1836. Accessed on document.write(currentDateStr);.
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ResourceID
spase://NASA/NumericalData/TIMED/SEE/L4_XSP
Description
The SEE XPS Level 4 data are derived from the XPS Level 1 data products. The XPS Level 4 processing algorithm uses reference CHIANTI spectral models to generate a higher spectral resolution (0.1 nm) estimate of the solar XUV irradiance by scaling the model reference spectra to match the XPS photometer currents (signal). The CHIANTI Quiet Sun (QS) spectrum and Active Region (AR) spectrum are used with a scaling of the AR spectrum to match the minimum signal on each day, and then a CHIANTI isothermal flare spectrum is scaled to match the signal above the daily minimum signal. The flare temperature is determined from the ratio of the GOES XRS 0.1-0.8 nm irradiance to the GOES XRS 0.05-0.4 nm irradiance. These scaling factors, flare temperature, and resulting model spectrum in the 0-40 nm range in 0.1 nm intervals are in the XPS Level 4 data product for every measurement made by XPS photometer #1 or #2 (0.1-7 nm band).
A SEE XPS Level 4 data product is produced for each UT day, and these daily products are also merged into three different full mission data files:
daily averages (24-hour)
orbit averages (3-min about every 97 min)
1-minute averages (but with only about 3% duty cycle)
The XPS Level 4 result in 0.1 nm intervals is also compressed into 1-nm intervals for use in the SEE Level 3 and Level 3A data products.
On-orbit instrument characterization is an ongoing effort, and the SEE team checks photometer degradation using redundant channels and underflight calibration rockets whose payload includes TIMED SEE prototype instruments.
The accuracy of the XPS Level 1 irradiance is 12%-26%, photometer dependent. There is additional uncertainty for applying the spectral model for the XPS Level 4 irradiances, and this estimated accuracy is 30% for the integrated XUV irradiance. The spectral distribution in the XPS Level 4 is from the CHIANTI model and not from direct measurements from XPS, a set of broadband photometers. The spectral distribution above 27 nm has been validated with the TIMED SEE EGS (27-190 nm, 0.4 nm resolution) measurements, so there is good confidence in the spectral distribution shortward of 27 nm.
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/TIMED/SEE/L4_XSP
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
TIMED SEE Level 4 XPS Modeled Solar Irradiance Data
DOI
https://doi.org/10.48322/v1q7-1836
ReleaseDate
2026-06-26 13:29:57Z
RevisionHistory
RevisionEvent
ReleaseDate
2020-07-07 21:15:38Z
Note
Only known prior ReleaseDate of the metadata
RevisionEvent
ReleaseDate
2025-11-14 16:01:52Z
Note
Added PublicationInfo. 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
2025-12-04 13:32:07Z
Note
Added MetadataRightsList. Updated to 2.7.1. ZCB
RevisionEvent
ReleaseDate
2026-02-16 14:46:16Z
Note
Added DOI. TLK
RevisionEvent
ReleaseDate
2026-06-26 13:29:57Z
Note
Add 'Z' to TemporalDescription:TimeSpan:StartDate. ZCB
Description
The SEE XPS Level 4 data are derived from the XPS Level 1 data products. The XPS Level 4 processing algorithm uses reference CHIANTI spectral models to generate a higher spectral resolution (0.1 nm) estimate of the solar XUV irradiance by scaling the model reference spectra to match the XPS photometer currents (signal). The CHIANTI Quiet Sun (QS) spectrum and Active Region (AR) spectrum are used with a scaling of the AR spectrum to match the minimum signal on each day, and then a CHIANTI isothermal flare spectrum is scaled to match the signal above the daily minimum signal. The flare temperature is determined from the ratio of the GOES XRS 0.1-0.8 nm irradiance to the GOES XRS 0.05-0.4 nm irradiance. These scaling factors, flare temperature, and resulting model spectrum in the 0-40 nm range in 0.1 nm intervals are in the XPS Level 4 data product for every measurement made by XPS photometer #1 or #2 (0.1-7 nm band).
A SEE XPS Level 4 data product is produced for each UT day, and these daily products are also merged into three different full mission data files:
daily averages (24-hour)
orbit averages (3-min about every 97 min)
1-minute averages (but with only about 3% duty cycle)
The XPS Level 4 result in 0.1 nm intervals is also compressed into 1-nm intervals for use in the SEE Level 3 and Level 3A data products.
On-orbit instrument characterization is an ongoing effort, and the SEE team checks photometer degradation using redundant channels and underflight calibration rockets whose payload includes TIMED SEE prototype instruments.
The accuracy of the XPS Level 1 irradiance is 12%-26%, photometer dependent. There is additional uncertainty for applying the spectral model for the XPS Level 4 irradiances, and this estimated accuracy is 30% for the integrated XUV irradiance. The spectral distribution in the XPS Level 4 is from the CHIANTI model and not from direct measurements from XPS, a set of broadband photometers. The spectral distribution above 27 nm has been validated with the TIMED SEE EGS (27-190 nm, 0.4 nm resolution) measurements, so there is good confidence in the spectral distribution shortward of 27 nm.
Acknowledgement
NASA, Thomas N. Woods
PublicationInfo
Authors
Woods, Thomas N.
PublicationDate
2025-11-14 16:01:52Z
PublishedBy
Johns Hopkins University Applied Physics Laboratory
Contacts
Role
Person
StartDate
StopDate
Note
1.
PrincipalInvestigator
spase://SMWG/Person/Thomas.N.Woods
InformationURL
Name
L4 Data Information
URL
http://lasp.colorado.edu/home/see/data/observational-averages/level-4-model/
PriorIDs
spase://VITMO/NumericalData/TIMED/SEE/L4_XSP
spase://VSPO/NumericalData/TIMED/SEE/L4_XSP
AccessInformation
RepositoryID
spase://SMWG/Repository/TIMED/SEE_POC
Availability
Online
AccessRights
Open
AccessURL
Name
SEE Data Products web page
URL
http://lasp.colorado.edu/home/see/data/
Description
This web page allows the request of data files for this product. To request data: for the L3A data type of interest, click the year of interest to go the the ftp directory of files and download the desired day-long file by clicking on it.
Format
NetCDF
Encoding
None
Acknowledgement
NASA, Thomas N. Woods
ProcessingLevel
Calibrated
ProviderResourceName
SEE Level 4 XPS Modeled Solar Irradiance data
ProviderProcessingLevel
Level 3A
ProviderVersion
11.01
InstrumentIDs
spase://SMWG/Instrument/TIMED/SEE
MeasurementType
Irradiance
TemporalDescription
TimeSpan
StartDate
2002-01-22 00:00:00.000Z
RelativeStopDate
P2D
ObservedRegion
Sun
Keywords
TIMED
SEE
Sun
Parameter #1
Name
Flare model temperature
ParameterKey
FMTEMP
Description
Flare model temperature derived from ratio of GOES XRS-B to XRS-A
Units
Log10(K)
Wave
WaveType
Electromagnetic
WaveQuantity
Intensity
Parameter #2
Name
solar irradiance spectrum
ParameterKey
MODELFLUX
Description
Array of solar irradiances in 0.1 nm bins from 0 to 40 nm (on 0.05 nm centers) based on scaling the Chianti spectral irradiance models using the calibrated XPS data and flare plasma temperature derived from GOES XRS
Units
W / m^2 / nm
Wave
WaveType
Electromagnetic
WaveQuantity
Wavelength
WavelengthRange
Low
0
High
40
Units
nm