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Data Access
GUVI POC L2B Neutral Density Product (IDLsave) Data Request
TIMED GUVI L2B Neutral Density Profiles
var authors='Christensen, Andrew B.';
document.write(authors);
(2025).
TIMED GUVI L2B Neutral Density Profiles.
[Data set].
Johns Hopkins University Applied Physics Laboratory.
https://doi.org/10.48322/4j7t-0x48. Accessed on document.write(currentDateStr);.
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ResourceID
spase://NASA/NumericalData/TIMED/GUVI/Neutral_Density_Product
Description
O2, N2, and O neutral density profiles over an orbit as a function of latitude and altitude derived from GUVI OI 135.6 nm and N2 LBH short and long radiance profiles.
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/Neutral_Density_Product
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
TIMED GUVI L2B Neutral Density Profiles
DOI
https://doi.org/10.48322/4j7t-0x48
ReleaseDate
2026-02-16 14:46:13Z
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 13:32:04Z
Note
Added MetadataRightsList. Updated to 2.7.1. ZCB
RevisionEvent
ReleaseDate
2026-02-16 14:46:13Z
Note
Added DOI. TLK
Description
O2, N2, and O neutral density profiles over an orbit as a function of latitude and altitude derived from GUVI OI 135.6 nm and N2 LBH short and long radiance profiles.
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
Neutral Density Profiles description
URL
http://guvitimed.jhuapl.edu/sites/default/files/data/documents/readme_GUVI_Version_13_Limb_Retrievals.pdf
PriorIDs
spase://VITMO/NumericalData/TIMED/GUVI/Neutral_Density_Product
spase://VSPO/NumericalData/TIMED/GUVI/Neutral_Density_Product
AccessInformation
RepositoryID
spase://SMWG/Repository/TIMED/GUVI_POC
Availability
Online
AccessRights
Open
AccessURL
Name
GUVI POC L2B Neutral Density Product (IDLsave) Data Request
URL
http://guvitimed.jhuapl.edu/data_fetch_l2b_ndp_idlsave
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
IDL
Encoding
None
Acknowledgement
NASA, Andrew B. Christensen
ProcessingLevel
Calibrated
ProviderResourceName
GUVI L2B Neutral Density Profiles
ProviderProcessingLevel
Level 2B
InstrumentIDs
spase://SMWG/Instrument/TIMED/GUVI
MeasurementType
Profile
TemporalDescription
TimeSpan
StartDate
2002-03-01 00:00:00.000Z
StopDate
2007-12-11 00:00:00.000Z
ObservedRegion
Earth.NearSurface.Thermosphere
ObservedRegion
Earth.NearSurface.AuroralRegion
Keywords
TIMED
GUVI
lower thermosphere
MLTI
Parameter #1
Name
Atomic Oxygen Number Density
ParameterKey
NDPSORBIT.OX
Description
Retrieved values of atomic oxygen number density from the inversion process
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
cm-3
Structure
Size
0
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (n is approximately 100).
Particle
ParticleType
Atom
ParticleQuantity
NumberDensity
Parameter #2
Name
Molecular Oxygen Number Density
ParameterKey
NDPSORBIT.O2
Description
Retrieved values of molecular oxygen number density from the inversion process
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
cm-3
Structure
Size
0
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Molecule
ParticleQuantity
NumberDensity
Parameter #3
Name
Molecular Nitrogen Number Density
ParameterKey
NDPSORBIT.N2
Description
Retrieved values of molecular nitrogen number density from the inversion process
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
cm-3
Structure
Size
0
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Molecule
ParticleQuantity
NumberDensity
Parameter #4
Name
Temperature
ParameterKey
NDPSORBIT.T
Description
Retrieved values of temperature from the inversion process
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
kelvin
Structure
Size
0
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Atom
ParticleType
Molecule
ParticleQuantity
Temperature
Parameter #5
Name
Uncertainty in Atomic Oxygen Number Density
ParameterKey
NDPSORBIT.SIG0X
Description
1-sigma uncertainty in atomic oxygen number density
Units
cm-3
Structure
Size
0
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Molecule
ParticleQuantity
NumberDensity
Parameter #6
Name
Uncertainty in Molecular Oxygen Number Density
ParameterKey
NDPSORBIT.SIG02
Description
1-sigma uncertainty in molecular oxygen number density
Units
cm-3
Structure
Size
0
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Molecule
ParticleQuantity
NumberDensity
Parameter #7
Name
Uncertainty in Molecular Nitrogen Number Density
ParameterKey
NDPSORBIT.SIGN2
Description
1-sigma uncertainty in molecular nitrogen number density
Units
cm-3
Structure
Size
21 100
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Molecule
ParticleQuantity
NumberDensity
Parameter #8
Name
Uncertainty in Temperature
ParameterKey
NDPSORBIT.SIGT
Description
1-sigma uncertainty in temperature
Units
kelvin
Structure
Size
21 100
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Atom
ParticleType
Molecule
ParticleQuantity
Temperature
Parameter #9
Name
Qeuv
ParameterKey
NDPSORBIT.QEUV
Description
The solar energy flux from the TIMED/SEE data. Multiply Qeuv by MORBIT(0).M(4) x MORBIT(0).M(7) to obtain the solar flux required to fit the GUVI dayglow.
Units
mW/m2
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Wave
WaveType
Electromagnetic
WaveQuantity
EnergyFlux
Parameter #10
Name
Altitude
ParameterKey
NDPSORBIT.ZM
Description
Altitude grid in model
Units
km
Structure
Size
21 100
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Support
SupportQuantity
Positional
Parameter #11
Name
O/N2 column ratio
ParameterKey
NDPSORBIT.O_N2
Description
O/N2 column ratio computed from retrieved O and N2 densities
Units
km
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Support
Qualifier
Ratio
SupportQuantity
Other
Parameter #12
Name
NRLMSIS Atomic Oxygen Number Density
ParameterKey
NDPSORBIT.OX0
Description
Values of atomic oxygen number density from the output of the NRLMIS model predictions
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
cm-3
Structure
Size
21 100
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Atom
ParticleQuantity
NumberDensity
Parameter #13
Name
NRLMSIS Molecular Oxygen Number Density
ParameterKey
NDPSORBIT.O20
Description
Values of molecular oxygen number density from the output of the NRLMIS model predictions
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
cm-3
Structure
Size
21 100
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Molecule
ParticleQuantity
NumberDensity
Parameter #14
Name
NRLMSIS Molecular Nitrogen Number Density
ParameterKey
NDPSORBIT.N20
Description
Values of molecular nitrogen number density from the output of the NRLMIS model predictions
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
cm-3
Structure
Size
21 100
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Molecule
ParticleQuantity
NumberDensity
Parameter #15
Name
NRLMSIS Temperature
ParameterKey
NDPSORBIT.T0
Description
Values of temperature from the ioutput of the NRLMIS model predictions
Caveats
Note that the retrieved densities and temperatures are given for the full zm (110 - 667 km) altitude range. But the highest accuracy is due to sensitivity of the dayglow between about 150 and 300 km to the parameters. So densities outside of that altitude range should be viewed as extrapolations of the best-fit model within that interval. However, our initial comparisons with total mass densities above 400 km from satellite drag and accelerometers show good agreement with the GUVI retrievals?a very promising result. If any of the elements in the FLAG parameter are set, retrievals should be used with caution, or preferably not used at all
Units
kelvin
Structure
Size
21 100
Description
Dimensions: [n,i] - where n is the number of levels in a limb scan (n is nominally 21); i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Particle
ParticleType
Atom
ParticleType
Molecule
ParticleQuantity
Temperature
Parameter #16
Name
NRLMSIS O/N2 column ratio
ParameterKey
NDPSORBIT.O_N20
Description
O/N2 column ratio computed from NRLMSIS O and N2 densities
Units
km
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Support
Qualifier
Ratio
SupportQuantity
Other
Parameter #17
Name
Iteration steps
ParameterKey
NDPSORBIT.N_STEPS
Description
The number of retrieval iteration steps for a given limb scan
Units
unitless
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Support
SupportQuantity
Other
Parameter #18
Name
Data Quality Flag
ParameterKey
NDPSORBIT.FLAG
Description
Data quality flag of the retrieved values of densities and temperatures from the inversion process. Most data with flags set to 1 have been removed.
Units
unitless
Structure
Size
3
Description
Dimensions: (3, n, i), where 3 is a 3-element vector; n is a n-level profile (nominally n is 21); and i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Element
Name
flag_0
Index
0
UnitsConversion
A value of zero means the retrieval was nominal; a value of one means the number of iteration steps for a given limb scan reached 20 without convergence in the retrieval process.
Element
Name
flag_1
Index
1
UnitsConversion
A value of zero means the retrieval was nominal; a value of one means any of the model parameters hit the a priori upper and lower limits.
Element
Name
flag_2
Index
2
UnitsConversion
A value of zero means the retrieval was nominal; a value of one means the altitude of peak intensity was too close to a boundary.
Support
SupportQuantity
Other
Parameter #19
Name
Day of year
ParameterKey
NDPSORBIT.IYD
Description
The day of year of the limb scan
Units
days
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
ValidMin
1
ValidMax
366
Support
SupportQuantity
Temporal
Parameter #20
Name
Seconds of day
ParameterKey
NDPSORBIT.SEC
Description
The UT seconds of day of the limb scan
Units
UT seconds
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
ValidMin
0
ValidMax
86400
Support
SupportQuantity
Temporal
Parameter #21
Name
Geolocated latitude
ParameterKey
NDPSORBIT.GLAT
Description
The geolocated latitude of the limb scan assigned to the tangent point near the peak of the airglow layer, roughly 160 km
Units
degrees
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
ValidMin
-90
ValidMax
90
Support
SupportQuantity
Positional
Parameter #22
Name
Geolocated longitude
ParameterKey
NDPSORBIT.GLONG
Description
The geolocated longitude of the limb scan assigned to the tangent point near the peak of the airglow layer, roughly 160 km
Units
degrees
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
ValidMin
-180
ValidMax
180
Support
SupportQuantity
Positional
Parameter #23
Name
Solar time
ParameterKey
NDPSORBIT.STLP
Description
The solar time of the limb scan
Units
hours
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
ValidMin
0
ValidMax
24
Support
SupportQuantity
Positional
Parameter #24
Name
Averaged f10.7
ParameterKey
NDPSORBIT.F107a
Description
The 81-day average of the observed solar 10.7-cm radio flux as recorded by DRAO at Pentiction, British Columbia, Canada, at 2000 UT.
Units
10-22W m-2 Hz-1
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Wave
WaveType
Electromagnetic
WaveQuantity
EnergyFlux
Parameter #25
Name
Previous-day f10.7
ParameterKey
NDPSORBIT.F107
Description
The previous-day observed solar 10.7-cm radio flux as recorded by DRAO at Pentiction, British Columbia, Canada, at 2000 UT.
Units
10-22W m-2 Hz-1
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Wave
WaveType
Electromagnetic
WaveQuantity
EnergyFlux
Parameter #26
Name
f10.7
ParameterKey
NDPSORBIT.F107_0
Description
The current-day observed solar 10.7-cm radio flux as recorded by DRAO at Pentiction, British Columbia, Canada, at 2000 UT.
Units
10-22W m-2 Hz-1
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Wave
WaveType
Electromagnetic
WaveQuantity
EnergyFlux
Parameter #27
Name
Ap
ParameterKey
NDPSORBIT.AP
Description
The current-day daily geomagnetic Ap index.
Units
unitless
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
ValidMin
0
ValidMax
400
Support
SupportQuantity
Other
Parameter #28
Name
Solar zenith angle
ParameterKey
NDPSORBIT.SZA
Description
The solar zenith angle at the geolocated tangent point.
Units
degrees
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
ValidMin
-180
ValidMax
180
Support
Qualifier
Direction
SupportQuantity
Positional
Parameter #29
Name
Model parameters structure
ParameterKey
MORBIT
Description
A structure containing the model parameters and other information and constraints. Components are M, an array of model parameters, which are retrieved from the inversion process; MINIT, an array of initial guesses of the parameter vector, M ; NAME, an array containing the string name of the model parameter; CHANGE, an array indicating the parameters that are allowed to vary during the inversion process, LOWERLIMIT, an array indicating the lower limits of the parameter, UPPERLIMIT, an array indicating the upper limits of the parameter, COVFIT, a covariance matrix for the retrieved model parameters.
Units
various
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Support
SupportQuantity
Other
Parameter #30
Name
Data structure
ParameterKey
DORBIT
Description
A structure containing the data, retrieved fits, and other information. Components are DIN, an array of the original data; NAME, an array containing the name of the measured intensity (eg, 1356 or LBH); D, an array containing the best fit model intensities; D0, an array containing the intensities computed using the initial guess parameters; ALT, an array containing the tangent altitudes for the intensities; COVDATA, an array containing the covariance of the data.
Units
various
Structure
Size
0
Description
Dimensions: [i] - where i is the number of limb scans (i.e., records) in an orbital file (i is approximately 100).
Support
SupportQuantity
Other