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Data Access
GUVI POC L1B Imaging Data Request
TIMED GUVI Imaging Level 1B Disk
var authors='Christensen, Andrew B.';
document.write(authors);
(2025).
TIMED GUVI Imaging Level 1B Disk.
[Data set].
Johns Hopkins University Applied Physics Laboratory.
https://doi.org/10.48322/dqfm-g937. Accessed on document.write(currentDateStr);.
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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/TIMED/GUVI/Imaging/L1B_Disk
Description
Level 1B Disk data contains calibrated radiance data over multiple scans that are geolocated into a GUVI-based coordinate system on the disk.
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/GUVI/Imaging/L1B_Disk
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
TIMED GUVI Imaging Level 1B Disk
DOI
https://doi.org/10.48322/dqfm-g937
ReleaseDate
2026-07-21 12:08:08Z
RevisionHistory
RevisionEvent
ReleaseDate
2021-06-02 00:00:00Z
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 13:32:05Z
Note
Added MetadataRightsList. Updated to 2.7.1. ZCB
RevisionEvent
ReleaseDate
2026-02-16 14:46:11Z
Note
Added DOI. TLK
RevisionEvent
ReleaseDate
2026-06-26 13:29:51Z
Note
Add 'Z' to TemporalDescription:TimeSpan:StartDate, TemporalDescription:TimeSpan:StopDate. ZCB
RevisionEvent
ReleaseDate
2026-07-21 12:08:08Z
Note
Added HelioData InformationURL. JWL
Description
Level 1B Disk data contains calibrated radiance data over multiple scans that are geolocated into a GUVI-based coordinate system on the disk.
Acknowledgement
NASA, Andrew B. Christensen
PublicationInfo
Authors
Christensen, Andrew B.
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/Andrew.B.Christensen
InformationURL
Name
L1B Imaging Data Information
URL
http://guvitimed.jhuapl.edu/sites/default/files/data/documents/L1B_datainfo.pdf
InformationURL
Name
HelioData
URL
https://helio.data.nasa.gov/dataset/TIMED_GUVI_Imaging_L1B_Disk
Description
The HelioData dataset page provides an overview of the dataset with access links, associated variables, and more.
PriorIDs
spase://VITMO/NumericalData/TIMED/GUVI/Imaging/L1B_Disk
spase://VSPO/NumericalData/TIMED/GUVI/Imaging/L1B_Disk
AccessInformation
RepositoryID
spase://SMWG/Repository/TIMED/GUVI_POC
Availability
Online
AccessRights
Open
AccessURL
Name
GUVI POC L1B Imaging Data Request
URL
http://guvitimed.jhuapl.edu/data_fetch_l1b_imaging
Description
This web page allows the request of data files for this product. To request data: select the year and day then press display.
Format
NetCDF
Encoding
GZIP
Acknowledgement
NASA, Andrew B. Christensen
ProcessingLevel
Calibrated
ProviderResourceName
GUVI Imaging L1B Disk data
ProviderProcessingLevel
Level 1B
ProviderVersion
009
InstrumentIDs
spase://SMWG/Instrument/TIMED/GUVI
MeasurementType
Radiance
TemporalDescription
TimeSpan
StartDate
2002-01-07 00:00:00.000Z
StopDate
2007-12-11 00:05:38.000Z
ObservedRegion
Earth.NearSurface.Thermosphere
ObservedRegion
Earth.NearSurface.Ionosphere
ObservedRegion
Earth.NearSurface.AuroralRegion
Keywords
TIMED
GUVI
Imaging
Disk
lower thermosphere
ionosphere
MLTI
Parameter #1
Name
Starting Time
ParameterKey
Starting_Time
Description
Starting date/time of file's observation encoded in a 13-digit string and stored as a single netCDF global attribute.
Units
yyyydoyhhmmss
Structure
Size
1
Description
Dimensions: [1] - this parameter is a single element per file.
Support
SupportQuantity
Temporal
Parameter #2
Name
Stopping Time
ParameterKey
Stopping_Time
Description
Stopping date/time of file's observation encoded in a 13-digit string and stored as a single netCDF global attribute.
Units
yyyydoyhhmmss
Structure
Size
1
Description
Dimensions: [1] - this parameter is a single element per file.
Support
SupportQuantity
Temporal
Parameter #3
Name
Day of Year
ParameterKey
DOY
Description
Date of observation in number of days since start of current year.
Units
days
Structure
Size
0
Description
Dimensions: [n] - where n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
1
ValidMax
366
Support
SupportQuantity
Temporal
Parameter #4
Name
Time
ParameterKey
Time
Description
Time of observation in integral number of milliseconds since start of current day. Timestamp marks beginning of interval
Units
ms
UnitsConversion
1e-3>s
Structure
Size
0
Description
Dimensions: [n] - where n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
0
ValidMax
86399999
Support
SupportQuantity
Temporal
Parameter #5
Name
Detector
ParameterKey
Detector
Description
Detector number of detector being used
Units
unitless
Structure
Size
0
Description
Dimensions: [n] - where n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
1
ValidMax
2
Support
SupportQuantity
Other
Parameter #6
Name
Slit position
ParameterKey
Slit
Description
Slit position being used where 0 = closed, 1 = wide, 2 = medium, 3 = narrow, and 4 = unknown.
Units
unitless
Structure
Size
0
Description
Dimensions: [n] - where n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
0
ValidMax
4
Support
SupportQuantity
InstrumentMode
Parameter #7
Name
Mirror start position
ParameterKey
MirrorStartPosition
Description
Starting position of the mirror.
Units
unitless
Structure
Size
0
Description
Dimensions: [n] - where n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
49
ValidMax
53
Support
SupportQuantity
Other
Parameter #8
Name
Mirror nadir position
ParameterKey
MirrorNadirPosition
Description
Position of the mirror when at nadir.
Units
unitless
Structure
Size
0
Description
Dimensions: [n] - where n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
249
ValidMax
253
Support
SupportQuantity
Other
Parameter #9
Name
Dark count pixels
ParameterKey
DarkCountPixels
Description
Four separate dark pixels that measure instumental dark counts. These values are use to scale a dark pixel mask to obtain an estimated dark level that can then subtracted from each pixel.
Caveats
This correction is generally not applied because the GUVI dark pixels seem to see varying amounts of scattered light at a level substantially larger than the miniscule "true" dark level.
Units
counts
Structure
Size
4
Description
Dimensions: [4,n] - where 4 is the number of dark count pixels, or NumDarkCountPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
Support
SupportQuantity
Other
Parameter #10
Name
Background count pixels
ParameterKey
BackgroundPixels
Description
GUVI long backgrounds measured on a 3x7 grid (3 spatial pixel intervals, 7 scan/mirror step intervals), and integrated for time intervals of [1.088, 1.674,1.674, 1.674, 1.674, 1.674, 1.488] seconds, finishing at scan/mirror steps [ 31, 26, 53, 80, 107, 134, 158]. The first 32 steps are on the limb (1.088 = 32x0.034 seconds/ limb step), whereas the next six intervals are distributed across the 159 disk scan steps.
Units
counts
Structure
Size
21
Description
Dimensions: [21,n] - where 21 is the number of background count pixels, or NumBackgroundCountPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
Support
SupportQuantity
Other
Parameter #11
Name
Data Quality Indicator
ParameterKey
DQI
Description
Data quality indicator as bit-encoded integers where Bit 7: 1 = Negative Radiance, 0 = positive; Bit 6: 1 = Zero Radiance, 0 = non-zero; Bit 5: 1 = Geolocation error (disk pixel on limb or limb pixel on disk), 0 = correct geolocation; Bit 4: 1 = Calibration failure, 0 = No calibration failure; Bits 0-3 are unused.
Units
unitless
Structure
Size
5 14 159
Description
Dimensions: [5,14,159,n] - where 5 is the number of colors, or NumColors; 14 is the number of along track pixels, or NumAlongTrackPixels; 159 is the number of across track pixels, or NumAcrossTrackPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
Support
SupportQuantity
Other
Parameter #12
Name
Pierce point latitude
ParameterKey
PiercePointLatitude
Description
Pierce point latitude geographic coordinates
Units
degrees
Structure
Size
14 159
Description
Dimensions: [14,159,n] - where 14 is the number of along track pixels, or NumAlongTrackPixels; 159 is the number of across track pixels, or NumAcrossTrackPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
-90.0
ValidMax
90.0
Support
SupportQuantity
Positional
Parameter #13
Name
Pierce point longitude
ParameterKey
PiercePointLongitude
Description
Pierce point longitude geographic coordinates
Units
degrees
Structure
Size
14 159
Description
Dimensions: [14,159,n] - where 14 is the number of along track pixels, or NumAlongTrackPixels; 159 is the number of across track pixels, or NumAcrossTrackPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
-180.0
ValidMax
180.0
Support
SupportQuantity
Positional
Parameter #14
Name
Calibration Error
ParameterKey
CalibrationError
Description
Calibration error
Units
Percent scaled by 10
UnitsConversion
1e-1>%
Structure
Size
5 14 159
Description
Dimensions: [5,14,159,n] - where 5 is the number of colors, or NumColors; 14 is the number of along track pixels, or NumAlongTrackPixels; 159 is the number of across track pixels, or NumAcrossTrackPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
0
ValidMax
1000
Support
SupportQuantity
Other
Parameter #15
Name
Counting Statistical Error
ParameterKey
CountError
Description
Count error
Caveats
If Bit 6 of Data Quality Indicator (DQI) parameter is set, then set the value returned is in units of Rayleighs/count (unscaled)
Units
Percent scaled by 10
UnitsConversion
1e-1>%
Structure
Size
5 14 159
Description
Dimensions: [5,14,159,n] - where 5 is the number of colors, or NumColors; 14 is the number of along track pixels, or NumAlongTrackPixels; 159 is the number of across track pixels, or NumAcrossTrackPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
ValidMin
0
Support
SupportQuantity
Other
Parameter #16
Name
Solar Zenith Angle
ParameterKey
SolarZenithAngle
Description
Solar Zenith Angle
Units
degrees
Structure
Size
14 159
Description
Dimensions: [14,159,n] - where 14 is the number of along track pixels, or NumAlongTrackPixels; 159 is the number of across track pixels, or NumAcrossTrackPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
Support
SupportQuantity
Other
Parameter #17
Name
Imaging Mode Disk Radiance Data
ParameterKey
RadianceData
Description
Radiance scans of nominally 159 pixels crosstrack and 14 pixels along track for each of 5 colors (1216, 1304, 1356 A, LBH1 and LBH2).
Units
Rayleighs
Structure
Size
5 14 159
Description
Dimensions: [5,14,159,n] - where 5 is the number of colors, or NumColors; 14 is the number of along track pixels, or NumAlongTrackPixels; 159 is the number of across track pixels, or NumAcrossTrackPixels; n is the number of scans, or NumScans, (i.e., records) in an orbital file.
Wave
WaveType
Electromagnetic
WaveQuantity
Wavelength
WavelengthRange
SpectralRange
Ultraviolet
Low
121.6
High
180.0
Units
nm
Bin
BandName
HI (121.6)
Low
121.6
High
121.6
Bin
BandName
OI (130.4)
Low
130.4
High
130.4
Bin
BandName
OI (135.6)
Low
135.6
High
135.6
Bin
BandName
N2 Lyman-Birge-Hopfield (LBH (1))
Low
140
High
150
Bin
BandName
N2 Lyman-Birge-Hopfield (LBH (2))
Low
165
High
180