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Data Access
GUVI POC L2B Electron Density Product (IDLsave) Data Request
FTP access to files at SPDF
HTTPS from SPDF
FTPS from SPDF (not with most browsers)
HTTPS from SPDF
CDAWeb
WebService:
CDAWeb Programmatic Data Access
HAPI: CDAWeb HAPI Server
TIMED GUVI L2B Electron Density Profiles
var authors='Christensen, Andrew, B.';
document.write(authors);
(2023).
TIMED GUVI L2B Electron Density Profiles.
[Data set].
Johns Hopkins University Applied Physics Laboratory; Space Physics Data Facility.
https://doi.org/10.48322/pzbn-gq12. Accessed on document.write(currentDateStr);.
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ResourceID
spase://NASA/NumericalData/TIMED/GUVI/Electron_Density_Product
Description
The Level-2 Electron Density Profiles data product contains F-region electron density as a function of altitude and latitude derived from the GUVI limb data. Summaries of estimated peak electron density and total electron content are also given as Level 3 products. The profiles are derived from the 135.6-nm channel of the GUVI limb data. The 135.6-nm emission at night is due almost exclusively to recombination of O+ ions. Since O+ is the primary ion in the F region, the 135.6-nm volume emission rate is closely related to the square of the electron density. Details of the procedure of producing the electron densities are given in: DeMajistre, R., L.J. Paxton, D. Morrison, J-H. Yee, L.P. Goncherenko and A.B. Christensen, Retrievals of nighttime electron density from Thermosphere Ionosphere Mesosphere and Dynamics (TIMED) mission Global Ultraviolet Imager (GUVI) Measurements, J. Geophys Res., 109, A05305, doi:10.1029/2003JA010296.
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/Electron_Density_Product
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
TIMED GUVI L2B Electron Density Profiles
DOI
https://doi.org/10.48322/pzbn-gq12
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
2023-07-30 12:34:56.789Z
Note
Added DOI and PublicationInfo minted by LFB, metadata versioned up to SPASE 2.6.0, reviewed by LFB 20230727
RevisionEvent
ReleaseDate
2025-10-03 11:24:14Z
Note
Updated PublishedBy name to match ROR Registry. 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
2025-10-22 12:34:56.789Z
Note
Revised ObservedRegion. JMW
RevisionEvent
ReleaseDate
2025-12-04 13:32:04Z
Note
Added MetadataRightsList and RightsList(s). Updated to 2.7.1. ZCB
RevisionEvent
ReleaseDate
2026-06-26 13:29:51Z
Note
Add 'Z' to RevisionEvent:ReleaseDate(s), PublicationDate. ZCB
RevisionEvent
ReleaseDate
2026-07-21 12:08:08Z
Note
Added HelioData InformationURL. JWL
Description
The Level-2 Electron Density Profiles data product contains F-region electron density as a function of altitude and latitude derived from the GUVI limb data. Summaries of estimated peak electron density and total electron content are also given as Level 3 products. The profiles are derived from the 135.6-nm channel of the GUVI limb data. The 135.6-nm emission at night is due almost exclusively to recombination of O+ ions. Since O+ is the primary ion in the F region, the 135.6-nm volume emission rate is closely related to the square of the electron density. Details of the procedure of producing the electron densities are given in: DeMajistre, R., L.J. Paxton, D. Morrison, J-H. Yee, L.P. Goncherenko and A.B. Christensen, Retrievals of nighttime electron density from Thermosphere Ionosphere Mesosphere and Dynamics (TIMED) mission Global Ultraviolet Imager (GUVI) Measurements, J. Geophys Res., 109, A05305, doi:10.1029/2003JA010296.
Acknowledgement
NASA, Andrew B. Christensen
PublicationInfo
Authors
Christensen, Andrew, B.
PublicationDate
2023-01-01 00:00:00Z
PublishedBy
Johns Hopkins University Applied Physics Laboratory; Space Physics Data Facility
Contacts
Role
Person
StartDate
StopDate
Note
1.
PrincipalInvestigator
spase://SMWG/Person/Andrew.B.Christensen
2.
MetadataContact
spase://SMWG/Person/Lee.Frost.Bargatze
InformationURL
Name
Electron Density Profiles description
URL
http://guvitimed.jhuapl.edu/sites/default/files/data/documents/readme_GUVI_Version_13_Limb_Retrievals.pdf
InformationURL
Name
HelioData
URL
https://helio.data.nasa.gov/dataset/TIMED_GUVI_Electron_Density_Product
Description
The HelioData dataset page provides an overview of the dataset with access links, associated variables, and more.
PriorIDs
spase://VITMO/NumericalData/TIMED/GUVI/Electron_Density_Product
spase://VSPO/NumericalData/TIMED/GUVI/Electron_Density_Product
AccessInformation
RepositoryID
spase://SMWG/Repository/TIMED/GUVI_POC
Availability
Online
AccessRights
Open
AccessURL
Name
GUVI POC L2B Electron Density Product (IDLsave) Data Request
URL
http://guvitimed.jhuapl.edu/data_fetch_l2b_edp_netcdf
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
None
Acknowledgement
NASA, Andrew B. Christensen
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb
Availability
Online
AccessRights
Open
RightsList
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 NASA Heliophysics data products
AccessURL
Name
FTP access to files at SPDF
URL
ftps://spdf.gsfc.nasa.gov/pub/data/timed/guvi/levels/level2b_e/edp/cdf/
Description
SPDF repository of TIMED Level-2 Electron Density Profiles in CDF format at CDAWeb
AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/timed/guvi/levels/level2b_e/edp/cdf/
Description
HTTPS from SPDF. Note: this AccessURL element was added by HDPWS.
AccessURL
Name
FTPS from SPDF (not with most browsers)
URL
ftps://spdf.gsfc.nasa.gov/pub/data/timed/guvi/levels/level2b_e/edp/cdf/
Description
SPDF repository of TIMED Level-2 Electron Density Profiles in CDF format at CDAWeb
AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/timed/guvi/levels/level2b_e/edp/cdf/
Description
HTTPS from SPDF. Note: this AccessURL element was added by HDPWS.
Format
CDF
Acknowledgement
Please acknowledge the support from CDAWeb team at GSFC/SPDF.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb
Availability
Online
AccessRights
Open
RightsList
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 NASA Heliophysics data products
AccessURL
Name
CDAWeb
URL
https://cdaweb.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=TIMED_EDP_GUVI&index=sp_phys
ProductKey
TIMED_EDP_GUVI
Description
TIMED GUVI L2 data with subset, plot, list from CDAWeb
Format
Text
AccessDirectoryTemplate
https://cdaweb.gsfc.nasa.gov/pub/data/timed/guvi/levels_v10/level2b_e/edp/cdf/$Y/$m
AccessFilenameTemplate
timed_edp_guvi_$Y$m$d$H$M$S_$v.cdf
Acknowledgement
Please acknowledge the support from the CDAWeb team at GSFC/SPDF.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
Availability
Online
AccessRights
Open
AccessURL
Name
CDAWeb Programmatic Data Access
URL
https://cdaweb.gsfc.nasa.gov/WS/cdasr/1/dataviews/sp_phys/datasets/TIMED_EDP_GUVI/clientLibraryExample/
Style
WebService
ProductKey
TIMED_EDP_GUVI
Description
Access to this data from common programming environments. Note: this AccessInformation element was added by HDPWS.
Format
Binary
Acknowledgement
Please acknowledge the support from the CDAWeb team at GSFC/SPDF.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb
Availability
Online
AccessRights
Open
RightsList
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 NASA Heliophysics data products
AccessURL
Name
CDAWeb HAPI Server
URL
https://cdaweb.gsfc.nasa.gov/hapi
Style
HAPI
ProductKey
TIMED_EDP_GUVI
Description
Web Service to this product using the HAPI interface.
Format
CSV
Acknowledgement
Please acknowledge the support from the CDAWeb team at GSFC/SPDF.
ProcessingLevel
Calibrated
ProviderResourceName
GUVI L2B Electron Density Product
ProviderProcessingLevel
Level 2B
InstrumentIDs
spase://SMWG/Instrument/TIMED/GUVI
MeasurementType
Profile
TemporalDescription
TimeSpan
StartDate
2002-03-22 00:00:00.000Z
StopDate
2007-12-11 00:00:00.000Z
ObservedRegion
Earth.NearSurface
ObservedRegion
Earth.NearSurface.Atmosphere
ObservedRegion
Earth.NearSurface.AuroralRegion
ObservedRegion
Earth.NearSurface.EquatorialRegion
ObservedRegion
Earth.NearSurface.Mesosphere
ObservedRegion
Earth.NearSurface.PolarCap
ObservedRegion
Earth.NearSurface.Stratosphere
ObservedRegion
Earth.NearSurface.Thermosphere
ObservedRegion
Earth.NearSurface.Ionosphere
Keywords
TIMED
GUVI
lower thermosphere
MLTI
Parameter #1
Name
Geographic Latitude
ParameterKey
glat
Description
Geographic Latitude (registered at ~300km)
Units
degrees
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Positional
Parameter #2
Name
Geographic Longitude
ParameterKey
glon
Description
Geographic Longitude (registered at ~300km)
Units
degrees
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Positional
Parameter #3
Name
Geomagnetic Latitude
ParameterKey
mlat
Description
Geomagnetic (simple dipole) Latitude (registered at ~300km)
Units
degrees
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Positional
Parameter #4
Name
Geomagnetic Longitude
ParameterKey
mlon
Description
Geomagnetic (simple dipole) Longitude (registered at ~300km)
Units
degrees
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Positional
Parameter #5
Name
Time
ParameterKey
time
Description
Universal Time of observation in 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 profiles (i.e., records) in an orbital file (n is approximately 136).
ValidMin
0
ValidMax
86399999
Support
SupportQuantity
Temporal
Parameter #6
Name
Electron Density
ParameterKey
ep
Description
Electron Density Profiles Data
Units
cm-3
Structure
Size
23
Description
Dimensions: [23,n] - where 23 is the number of levels in a profile; n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Particle
ParticleType
Electron
ParticleQuantity
NumberDensity
Parameter #7
Name
Retrieved Uncertainty in Electron Density
ParameterKey
sigep
Description
Retrieved Uncertainty in Electron Density
Units
cm-3
Structure
Size
23
Description
Dimensions: [23,n] - where 23 is the number of levels in a profile; n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Particle
ParticleType
Electron
ParticleQuantity
NumberDensity
Parameter #8
Name
Volume Emission Rate
ParameterKey
ver
Description
Volume Emission Rate
Units
Rayleighs
Structure
Size
23
Description
Dimensions: [23,n] - where 23 is the number of levels in a profile; n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Wave
WaveType
Electromagnetic
WaveQuantity
Emissivity
Parameter #9
Name
Uncertainty in Volume Emission Rate
ParameterKey
sigver
Description
Uncertainty in Volume Emission Rate
Units
Rayleighs
Structure
Size
23
Description
Dimensions: [23,n] - where 23 is the number of levels in a profile; n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Wave
WaveType
Electromagnetic
WaveQuantity
Emissivity
Parameter #10
Name
Atomic Oxygen Density Profile
ParameterKey
oden
Description
Atomic Oxygen Density Profile (from MSIS)
Units
cm-3
Structure
Size
23
Description
Dimensions: [23,n] - where 23 is the number of levels in a profile; n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Particle
ParticleType
Atom
ParticleQuantity
NumberDensity
Parameter #11
Name
Uncorrected Volume Emission Rate
ParameterKey
ver0
Description
Volume Emission Rate (no mutual neutralization correction)
Units
Rayleigh
Structure
Size
23
Description
Dimensions: [23,n] - where 23 is the number of levels in a profile; n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Wave
WaveType
Electromagnetic
WaveQuantity
Emissivity
Parameter #12
Name
Uncertainty in Uncorrected Volume Emission Rate
ParameterKey
sigver0
Description
Uncertainty in Volume Emission Rate (no mutual neutralization correction
Units
Rayleighs
Structure
Size
23
Description
Dimensions: [23,n] - where 23 is the number of levels in a profile; n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Wave
WaveType
Electromagnetic
WaveQuantity
Emissivity
Parameter #13
Name
Chapman Layer Maximum Density
ParameterKey
nmf2
Description
Chapman Layer Maximum Density
Units
cm-3
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #14
Name
Chapman Layer Maximum Radius
ParameterKey
rmf2
Description
Chapman Layer Maximum Radius
Units
km
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #15
Name
Chapman Layer Topside Scaleheight
ParameterKey
hmf2
Description
Chapman Layer Topside Scaleheight
Units
unitless
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #16
Name
Uncertainty in Chapman Layer Maximum Density
ParameterKey
signmf2
Description
Uncertainty in Chapman Layer Maximum Density
Units
cm -3
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #17
Name
Uncertainty in Chapman Layer Maximum Radius
ParameterKey
sigrmf2
Description
Uncertainty in Chapman Layer Maximum Radius
Units
km
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #18
Name
Uncertainty in Chapman Layer Topside Scaleheight
ParameterKey
sighmf2
Description
Uncertainty in Chapman Layer Topside Scaleheight
Units
unitless
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #19
Name
AACGM Geomagnetic Latitude
ParameterKey
acmlat
Description
Geomagnetic (AACGM) Latitude (registered at ~300km)
Units
degrees
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Positional
Parameter #20
Name
AACGM Geomagnetic Longitude
ParameterKey
acmlon
Description
Geomagnetic (AACGM) Longitude (registered at ~300km)
Units
degrees
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Positional
Parameter #21
Name
Earth radius
ParameterKey
re
Description
Earth radius at the given geographic latitude
Units
km
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #22
Name
Index map
ParameterKey
ind
Description
Index map into level 1B file
Units
unitless
Structure
Size
0
Description
Dimensions: [n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #23
Name
EDP/VER radius grid
ParameterKey
k_nonpar_r
Description
EDP/VER radius grid where altitude grid is (k_nonpar_r - re)
Units
km
Structure
Size
23
Description
Dimensions: [23] - where 23 is the number of levels in a profile.
Support
SupportQuantity
Other
Parameter #24
Name
Observational Angles for Observation
ParameterKey
k_nonpar_thetapix
Description
Observational Angles for Observation where tangent altitudes are (625.+Re)*sin(k_nonpar_thetapix) - re
Units
radian
Structure
Size
32
Description
Dimensions: [32].
Support
SupportQuantity
Other
Parameter #25
Name
Chapman Layers Parameters Existence flag
ParameterKey
pf
Description
If 1, chapman layers parameters present, 0 if not
Structure
Size
1
Description
Dimensions: [1] - a single value per orbital file.
Support
SupportQuantity
Other
Parameter #26
Name
Radiances at 135.6 nm
ParameterKey
prof
Description
Radiances at 135.6 nm
Units
Rayleigh
Structure
Size
32 14
Description
Dimensions: [32,14,n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #27
Name
Uncertainties of Radiances at 135.6 nm
ParameterKey
dprof
Description
Uncertainties of Radiances at 135.6 nm
Units
Rayleigh
Structure
Size
32 14
Description
Dimensions: [32,14,n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #28
Name
H+ Correction flag
ParameterKey
hpcor
Description
H+ correction from IRI made, -1 if not
Structure
Size
1
Description
Dimensions: [1] - a single value per orbital file.
Support
SupportQuantity
Other
Parameter #29
Name
Number of limb scans for smoothing
ParameterKey
ncomb(nonvariant_var)
Description
Number of limb scans for smoothing
Structure
Size
1
Description
Dimensions: [1] - a single value per orbital file.
Support
SupportQuantity
Other
Parameter #30
Name
k_nonpar_w0
ParameterKey
k_nonpar_w0
Structure
Size
448
Description
Dimensions: [448,n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #31
Name
k_nonpar_w1
ParameterKey
k_nonpar_w1
Structure
Size
448
Description
Dimensions: [448,n] - where n is the number of profiles (i.e., records) in an orbital file (n is approximately 136).
Support
SupportQuantity
Other
Parameter #32
Name
k_nonpar_w0c
ParameterKey
k_nonpar_w0c
Structure
Size
32 2
Description
Dimensions: [32,2].
Support
SupportQuantity
Other
Parameter #33
Name
k_nonpar_w1c
ParameterKey
k_nonpar_w1c
Structure
Size
32 2
Description
Dimensions: [32,2].
Support
SupportQuantity
Other
Parameter #34
Name
k_par_r
ParameterKey
k_par_r
Structure
Size
50
Description
Dimensions: [50].
Support
SupportQuantity
Other
Parameter #35
Name
k_par_thetapix
ParameterKey
k_par_thetapix
Structure
Size
32
Description
Dimensions: [32].
Support
SupportQuantity
Other
Parameter #36
Name
k_par_w0
ParameterKey
k_par_w0
Structure
Size
448 50
Description
Dimensions: [448,50].
Support
SupportQuantity
Other
Parameter #37
Name
k_par_w1
ParameterKey
k_par_w1
Structure
Size
448 50
Description
Dimensions: [448,50].
Support
SupportQuantity
Other