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Mars Global Surveyor Solar Wind Proxy Pressures

ResourceID
spase://NASA/NumericalData/MGS/MAG/SW-Proxy/PT2H

Description

Derivation of the solar wind dynamic pressure at Mars using Mars Global Surveyor data. There is no upstream solar wind monitor at Mars (as of the release of this data set). This data set is a proxy for the solar wind dynamic pressure derived from Mars Global Surveyor (MGS) Magnetometer (MAG) measurements. The rationale behind the proxy is that pressure is conserved in the solar wind interaction with Mars. At altitudes from ~400-800 km, the dominant pressure term is magnetic field pressure. We measure the magnetic field with MAG, calculate the pressure (B2/2µo) in that altitude range and assume that it balances the incident solar wind pressure. This proxy is reliable for determining relative solar wind pressure at Mars. Absolute values may deviate from the proxy. The pressure does drop with solar zenith angle (SZA). This affect is accounted for by fitting a function of SZA to the dayside, northern hemisphere data from an MGS pass. The number of points included in the fit is provided in the file. The standard deviation from the fit is also provided. Because we do a fit to one orbit's worth of dayside, northern hemisphere data, we obtain one value for PSW every orbit, which has a period of ~2 hr.

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Details

Version:2.2.9

NumericalData

ResourceID
spase://NASA/NumericalData/MGS/MAG/SW-Proxy/PT2H
ResourceHeader
ResourceName
Mars Global Surveyor Solar Wind Proxy Pressures
ReleaseDate
2020-07-07 21:14:45Z
Description

Derivation of the solar wind dynamic pressure at Mars using Mars Global Surveyor data. There is no upstream solar wind monitor at Mars (as of the release of this data set). This data set is a proxy for the solar wind dynamic pressure derived from Mars Global Surveyor (MGS) Magnetometer (MAG) measurements. The rationale behind the proxy is that pressure is conserved in the solar wind interaction with Mars. At altitudes from ~400-800 km, the dominant pressure term is magnetic field pressure. We measure the magnetic field with MAG, calculate the pressure (B2/2µo) in that altitude range and assume that it balances the incident solar wind pressure. This proxy is reliable for determining relative solar wind pressure at Mars. Absolute values may deviate from the proxy. The pressure does drop with solar zenith angle (SZA). This affect is accounted for by fitting a function of SZA to the dayside, northern hemisphere data from an MGS pass. The number of points included in the fit is provided in the file. The standard deviation from the fit is also provided. Because we do a fit to one orbit's worth of dayside, northern hemisphere data, we obtain one value for PSW every orbit, which has a period of ~2 hr.

Contacts
RolePersonStartDateStopDateNote
1.DataProducerspase://SMWG/Person/Dana.H.Crider
InformationURL
Name
Data Derivation Description from the Provider
URL
Description

Data Derivation Description from the Provider

PriorIDs
spase://VHO/NumericalData/MGS/MAG/SW-Proxy/PT2H
spase://VSPO/NumericalData/MGS/MAG/SW-Proxy/PT2H
AccessInformation
RepositoryID
Availability
Online
AccessRights
Open
AccessURL
Name
MGS Solar Wind Proxy
URL
Description

MGS Solar Wind Proxy yearly files at VHO

Format
Text
Encoding
ASCII
InstrumentIDs
MeasurementType
ThermalPlasma
TemporalDescription
TimeSpan
StartDate
1999-03-08 00:00:00Z
StopDate
2006-11-02 23:59:59Z
Cadence
PT2H
InputResourceID
Parameter #1
Name
Year
ParameterKey
Field 1
Description

Year

Support
SupportQuantity
Temporal
Parameter #2
Name
Fractional DOY
ParameterKey
Field 2
Description

Fractional Day of Year

Support
SupportQuantity
Temporal
Parameter #3
Name
Solar Wind Pressure
ParameterKey
Field 3
Description

Solar Wind Pressure Estimate (nPa)

Units
nPa
Particle
ParticleType
Proton
Qualifier
Magnitude
ParticleQuantity
Pressure
Parameter #4
Name
Number of Points in Fit
ParameterKey
Field 4
Description

Number of points used in fit

Support
SupportQuantity
Other
Parameter #5
Name
Standard Deviation
ParameterKey
Field 5
Description

Standard deviation of points in fit

Support
SupportQuantity
Other