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Data Access
FTPS from SPDF (not with most browsers)
HTTPS from SPDF
CDAWeb
WebService:
CDAWeb Programmatic Data Access
HAPI: CDAWeb HAPI Server
ACE Science Center ftp area
ACE Science Center
ACE Solar Wind Electron Proton Alpha Monitor (SWEPAM) 64-Second Level 2 Data
var authors='McComas, D., Skoug, R., Delapp, D., Elliott, H., and Davis, A.';
document.write(authors);
(2022).
ACE Solar Wind Electron Proton Alpha Monitor (SWEPAM) 64-Second Level 2 Data.
[Data set].
Space Physics Data Facility; California Institute of Technology.
https://doi.org/10.48322/tsfn-6v47. 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/ACE/SWEPAM/L2/PT64S
Description
Solar Wind Ion parameters from ACE/SWEPAM. Level 2 data, 64-second averages. Parameters include proton density, temperature (radial component) and flow speed, flow velocity vector in GSE, GSM and RTN coordinates, and alpha to proton density ratio. ACE position vectors in GSE and GSM are included. The data are accessible via ftp in HDF and CDF from the ACE Science Center and CDAWeb, respectively, and in ASCII format from the value-added interfaces at those sites. Hourly averaged L2 plasma parameters are also available from these access paths. The "parameter keys" given below are as used by CDAWeb.
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/ACE/SWEPAM/L2/PT64S
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
ACE Solar Wind Electron Proton Alpha Monitor (SWEPAM) 64-Second Level 2 Data
DOI
https://doi.org/10.48322/tsfn-6v47
ReleaseDate
2025-12-04 13:28:25Z
RevisionHistory
RevisionEvent
ReleaseDate
2021-04-27 15:38:11
Note
Last known prior metadata Release Date
RevisionEvent
ReleaseDate
2022-04-20 12:34:56.789
Note
ACE: DOI and PublicationInfo added, metadata revised by J.M. Weygand on 2022-04-08, reviewed by LFB
RevisionEvent
ReleaseDate
2022-05-17 12:34:56.789
Note
ACE: Updated to SPASE Version 2.4.0, three InformationURL URLs updated, revised by LFB on 2022-05-17
RevisionEvent
ReleaseDate
2025-09-30 14:27:19Z
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
2025-12-04 13:28:25Z
Note
Added MetadataRightsList and RightsList(s). Updated to 2.7.1. ZCB
Description
Solar Wind Ion parameters from ACE/SWEPAM. Level 2 data, 64-second averages. Parameters include proton density, temperature (radial component) and flow speed, flow velocity vector in GSE, GSM and RTN coordinates, and alpha to proton density ratio. ACE position vectors in GSE and GSM are included. The data are accessible via ftp in HDF and CDF from the ACE Science Center and CDAWeb, respectively, and in ASCII format from the value-added interfaces at those sites. Hourly averaged L2 plasma parameters are also available from these access paths. The "parameter keys" given below are as used by CDAWeb.
Acknowledgement
Please acknowledge the ACE/SWEPAM instrument team and the ACE Science Center
PublicationInfo
Authors
McComas, D., Skoug, R., Delapp, D., Elliott, H., and Davis, A.
PublicationDate
2022-04-27 00:00:00
PublishedBy
Space Physics Data Facility; California Institute of Technology
Contacts
Role
Person
StartDate
StopDate
Note
1.
TechnicalContact
spase://SMWG/Person/Ruth.Skoug
2.
PrincipalInvestigator
spase://SMWG/Person/David.J.McComas
InformationURL
Name
ACE SWEPAM Level 2 data Home Page
URL
https://izw1.caltech.edu/ACE/ASC/level2/swepam_l2desc.html
Description
ACE Science Center site hosting instrument information, data release notes, as well as web utilities for plotting and downloading data
InformationURL
Name
Rules of use, and caveats
URL
https://izw1.caltech.edu/ACE/ASC/level2/policy_lvl2.html
Description
ACE level 2 data rules of use, and caveats
PriorIDs
spase://VHO/NumericalData/ACE/SWEPAM/L2_PT64S
spase://VSPO/NumericalData/ACE/SWEPAM/L2/PT64S
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
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
FTPS from SPDF (not with most browsers)
URL
ftps://spdf.gsfc.nasa.gov/pub/data/ace/swepam/level_2_cdaweb/swe_h0/
Description
FTP repository of 64-second ACE SWEPAM data in CDF format at CDAWeb
AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/ace/swepam/level_2_cdaweb/swe_h0/
Description
In CDF via HTTP from SPDF
Format
CDF
Acknowledgement
Please acknowledge the ACE/SWEPAM instrument team, the ACE Science Center, and the CDAWeb team at GSFC/SPDF.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
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=AC_H0_SWE&index=sp_phys
ProductKey
AC_H0_SWE
Description
ACE/SWEPAM L2 64-sec data with subset, plot, list functionalities from CDAWeb
Format
Text
AccessDirectoryTemplate
https://cdaweb.gsfc.nasa.gov/pub/data/ace/swepam/level_2_cdaweb/swe_h0/$Y
AccessFilenameTemplate
ac_h0_swe_$Y$m$d_$v.cdf
Acknowledgement
Please acknowledge the ACE/SWEPAM instrument team, the ACE Science Center, and 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/AC_H0_SWE/clientLibraryExample/
Style
WebService
ProductKey
AC_H0_SWE
Description
Access to this data from common programming environments. Note: this AccessInformation element was added by HDPWS.
Format
Binary
Acknowledgement
Please acknowledge the ACE/SWEPAM instrument team, the ACE Science Center, and the CDAWeb team at GSFC/SPDF.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
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
AC_H0_SWE
Description
Web Service to this product using the HAPI interface.
Format
CSV
Acknowledgement
Please acknowledge the ACE/SWEPAM instrument team, the ACE Science Center, and the CDAWeb team at GSFC/SPDF.
AccessInformation
RepositoryID
spase://SMWG/Repository/ACE_SC
Availability
Online
AccessRights
Open
AccessURL
Name
ACE Science Center ftp area
URL
ftp://mussel.srl.caltech.edu/pub/ace/level2/swepam/
Description
In HDF via ftp from ACE Science Center
Format
HDF
Acknowledgement
Please acknowledge the ACE/SWEPAM instrument team and the ACE Science Center
AccessInformation
RepositoryID
spase://SMWG/Repository/ACE_SC
Availability
Online
AccessRights
Open
AccessURL
Name
ACE Science Center
URL
https://izw1.caltech.edu/ACE/ASC/level2/lvl2DATA_SWEPAM.html
Description
ACE/SWEPAM L2 64-sec data with subset, plot, list functionalities from the ACE Science Center
Format
Text
Acknowledgement
Please acknowledge the ACE/SWEPAM instrument team and the ACE Science Center
ProviderResourceName
ACE SWEPAM Level 2 Data, 64-second averages
ProviderProcessingLevel
Level 2
ProviderVersion
9
InstrumentIDs
spase://SMWG/Instrument/ACE/SWEPAM
MeasurementType
ThermalPlasma
TemporalDescription
TimeSpan
StartDate
1998-02-04 00:00:12Z
RelativeStopDate
-P2M
Cadence
PT64S
ObservedRegion
Heliosphere.NearEarth
Caveats
The quality of ACE level 2 data is such that it is suitable for serious scientific study. However, to avoid confusion and misunderstanding, it is recommended that users consult with the appropriate ACE team members before publishing work derived from the data. The ACE team has worked hard to ensure that the level 2 data are free from errors, but the team cannot accept responsibility for erroneous data, or for misunderstandings about how the data may be used. This is especially true if the appropriate ACE team members are not consulted before publication. At the very least, preprints should be forwarded to the ACE team before publication.
Parameter #1
Name
Time
ParameterKey
Epoch
Description
Number of milliseconds since CDF_EPOCH: 0000-01-01T00:00:00.000. Timestamp marks beginning of interval
Units
ms
UnitsConversion
1e-3>s
ValidMin
1996-01-01T00:00:00.000Z
ValidMax
2020-01-01T00:00:00.000Z
FillValue
-1.0E31
Support
SupportQuantity
Temporal
Parameter #2
Name
Time PB5
ParameterKey
Time_PB5
Description
Time of observation in year, day of year, and milliseconds. Timestamp marks beginning of interval
Structure
Size
3
Element
Name
Year
Index
1
Units
year
ValidMin
1997
ValidMax
2020
FillValue
-2147483648
Element
Name
Day of year
Index
2
Units
day
ValidMin
1
ValidMax
366
FillValue
-2147483648
Element
Name
Elapsed milliseconds of day
Index
3
Units
msec
ValidMin
0
ValidMax
86401000
FillValue
-2147483648
Support
SupportQuantity
Temporal
Parameter #3
Name
Proton Number density
ParameterKey
Np
Description
Solar Wind Proton Number Density, scalar
Caveats
Np is the proton number density in units of cm-3, as calculated by integrating the ion distribution function.
Units
cm^-3
ValidMin
0.0
ValidMax
200.0
FillValue
-1.0E31
Particle
ParticleType
Proton
Qualifier
Moment
ParticleQuantity
NumberDensity
Parameter #4
Name
Solar Wind Proton Speed
ParameterKey
Vp
Description
Solar Wind Bulk Speed
Caveats
Vp is the solar wind proton speed, or more generally just the solar wind (bulk) speed. It is obtained by integrating the ion (proton) distribution function.
Units
km/s
ValidMin
0.0
ValidMax
2500.0
FillValue
-1.0E31
Particle
ParticleType
Proton
Qualifier
Moment
Qualifier
Scalar
ParticleQuantity
Velocity
Parameter #5
Name
Proton Temperature
ParameterKey
Tpr
Description
radial component of the proton temperature
Caveats
The radial component of the proton temperature is the (1,1) component of the temperature tensor, along the radial direction. It is obtained by integration of the ion (proton) distribution function.
Units
Kelvin
ValidMin
1000.0
ValidMax
1100000.0
FillValue
-1.0E31
Particle
ParticleType
Proton
Qualifier
Moment
ParticleQuantity
Temperature
Parameter #6
Name
alpha/proton ratio
ParameterKey
alpha_ratio
Description
alpha to proton density ratio
Caveats
Alpha ratio (Na/Np) - is the ratio of the number density of helium++ ions to the number density of protons.
ValidMin
0.0
ValidMax
10.0
FillValue
-1.0E31
Particle
ParticleType
AlphaParticle
ParticleType
Proton
Qualifier
Ratio
ParticleQuantity
NumberDensity
Parameter #7
Name
Solar Wind Velocity (GSE)
ParameterKey
V_GSE
Description
Solar Wind Velocity in GSE cartesian coordinates, 64-second average
Caveats
Solar Wind Velocity in GSE coords, 64-second average
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSE
Structure
Size
3
Element
Name
VX (GSE)
Qualifier
Component.I
Index
1
ValidMin
-2000.0
ValidMax
0.0
FillValue
-1.0E31
Element
Name
VY (GSE)
Qualifier
Component.J
Index
2
ValidMin
-900.0
ValidMax
900.0
FillValue
-1.0E31
Element
Name
VZ (GSE)
Qualifier
Component.K
Index
3
ValidMin
-900.0
ValidMax
900.0
FillValue
-1.0E31
Particle
ParticleType
Proton
Qualifier
Moment
Qualifier
Vector
ParticleQuantity
Velocity
Parameter #8
Name
Solar Wind Velocity (RTN)
ParameterKey
V_RTN
Description
Solar Wind Velocity in RTN cartesian coordinates, 64-second average
Caveats
Solar Wind Velocity in RTN cartesian coordinates, 64-second average
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
RTN
Structure
Size
3
Element
Name
VR (RTN)
Qualifier
Component.I
Index
1
ValidMin
0.0
ValidMax
2000.0
FillValue
-1.0E31
Element
Name
VT (RTN)
Qualifier
Component.J
Index
2
ValidMin
-900.0
ValidMax
900.0
FillValue
-1.0E31
Element
Name
VN (RTN)
Qualifier
Component.K
Index
3
ValidMin
-900.0
ValidMax
900.0
FillValue
-1.0E31
Particle
ParticleType
Proton
Qualifier
Moment
Qualifier
Vector
ParticleQuantity
Velocity
Parameter #9
Name
Solar Wind Velocity (GSM)
ParameterKey
V_GSM
Description
Solar Wind Velocity in GSM cartesian coordinates, 64-second average
Caveats
Solar Wind Velocity in GSM ccartesian coordinates, 64-second average
Units
km/s
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
3
Element
Name
VX (GSM)
Qualifier
Component.I
Index
1
ValidMin
-1800.0
ValidMax
0.0
FillValue
-1.0E31
Element
Name
VY (GSM)
Qualifier
Component.J
Index
2
ValidMin
-900.0
ValidMax
900.0
FillValue
-1.0E31
Element
Name
VZ (GSM)
Qualifier
Component.K
Index
3
ValidMin
-900.0
ValidMax
900.0
FillValue
-1.0E31
Particle
ParticleType
Proton
Qualifier
Moment
Qualifier
Vector
ParticleQuantity
Velocity
Parameter #10
Name
S/C position in GSE
ParameterKey
SC_pos_GSE
Description
ACE s/c position in GSE coordinates
Units
km
UnitsConversion
1e3>m
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSE
Structure
Size
3
Element
Name
X GSE
Qualifier
Component.I
Index
1
ValidMin
-2000000.0
ValidMax
2000000.0
FillValue
-1.0E31
Element
Name
Y GSE
Qualifier
Component.J
Index
2
ValidMin
-2000000.0
ValidMax
2000000.0
FillValue
-1.0E31
Element
Name
Z GSE
Qualifier
Component.J
Index
3
ValidMin
-2000000.0
ValidMax
2000000.0
FillValue
-1.0E31
Support
SupportQuantity
Positional
Parameter #11
Name
S/C position in GSM
ParameterKey
SC_pos_GSM
Description
ACE s/c position in GSM coordinates
Units
km
UnitsConversion
1e3>m
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
3
Element
Name
X GSM
Qualifier
Component.I
Index
1
ValidMin
-2000000.0
ValidMax
2000000.0
FillValue
-1.0E31
Element
Name
Y GSM
Qualifier
Component.J
Index
2
ValidMin
-2000000.0
ValidMax
2000000.0
FillValue
-1.0E31
Element
Name
Z GSM
Qualifier
Component.K
Index
3
ValidMin
-2000000.0
ValidMax
2000000.0
FillValue
-1.0E31
Support
SupportQuantity
Positional