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TIMED GUVI Imaging Level 1B Disk

(2025). TIMED GUVI Imaging Level 1B Disk [Data set]. Johns Hopkins University Applied Physics Laboratory.

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.

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Details

Version:2.7.1

MetadataRightsList

Rights
SchemeURI
https://spdx.org/licenses/
RightsIdentifierScheme
SPDX
RightsIdentifier
CC0-1.0
RightsURI
https://spdx.org/licenses/CC0-1.0.html
RightsName
Creative Commons Zero v1.0 Universal
Note
CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions

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
ReleaseDate
2025-12-04 13:32:05Z
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
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
RolePersonStartDateStopDateNote
1.PrincipalInvestigatorspase://SMWG/Person/Andrew.B.Christensen
InformationURL
PriorIDs
spase://VITMO/NumericalData/TIMED/GUVI/Imaging/L1B_Disk
spase://VSPO/NumericalData/TIMED/GUVI/Imaging/L1B_Disk
AccessInformation
RepositoryID
Availability
Online
AccessRights
Open
AccessURL
Name
GUVI POC L1B Imaging Data Request
URL
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
MeasurementType
Radiance
TemporalDescription
TimeSpan
StartDate
2002-01-07 00:00:00.000
StopDate
2007-12-11 00:05:38.000
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