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Short product names

CH_DNS_ACC_2_CH_TEC_TMS_2FCH_WND_ACC_2_CS_MAGGF_DNSxACC_2_GF_NE__KBR_2FGF_TECxTMS_2FGF_WNDxACC_2_GFx_FGM_ACAL_CORRGO_MAG_ACAL_CORRGR_DNSxACC_2_GR_NE__KBR_2FGR_TECxTMS_2FGR_WNDxACC_2_GRACE_x_MAGMM_CON_EPH_2_SW_ACCx_AE_2_SW_ACCxCAL_2_SW_ACCxPOD_2_SW_AEJxLPL_2FSW_AEJxLPS_2FSW_AEJxPBL_2FSW_AEJxPBS_2FSW_AOBxFAC_2FSW_ASMxAUX_1BSW_ASMxBUR_1BSW_AUXxORBCNTSW_CFW_SHA_2YSW_DNSxACC_2_SW_DNSxPOD_2_SW_EEFxTMS_2FSW_EFIx_LP_1BSW_EFIx_LP_FPSW_EFIx_LP_HMSW_EFIx_TCT02SW_EFIx_TCT16SW_EFIx_TII1BSW_EFIxIDM_2_SW_EFIxLPI_1BSW_EFIxTIE_2_SW_EFIxTISH1BSW_EFIxTISL1BSW_EGF_SHA_2_SW_FAC_LLS_2FSW_FAC_TMS_2FSW_FACxTMS_2FSW_GPSx_RN_1BSW_GPSx_RO_1BSW_GPSxNAV_1BSW_IBIxTMS_2FSW_IBP_CLI_2_SW_IPDxIRR_2FSW_LP_x_CA_1BSW_MAGx_CA_1BSW_MAGx_HR_1BSW_MAGx_LR_1BSW_MCO_SHA_2CSW_MCO_SHA_2DSW_MCO_SHA_2FSW_MCO_SHA_2XSW_MCO_SHA_2YSW_MCR_1DM_2_SW_MIN_1DM_2_SW_MIO_SHA_2CSW_MIO_SHA_2DSW_MIO_SHA_2ESW_MITx_LP_2FSW_MITxTEC_2FSW_MLI_SHA_2CSW_MLI_SHA_2DSW_MLI_SHA_2ESW_MMA_SHA_2CSW_MMA_SHA_2FSW_MODx_SC_1BSW_MTI_SHA_2CSW_NIX_TMS_2FSW_PC1xMAG_2FSW_PPIxFAC_2FSW_SC_xDYN_1BSW_SP3xCOM_2_SW_SP3xKIN_2_SW_STRxATT_1BSW_STRxEPF_1BSW_TECxTMS_2FSW_TIX_TMS_2FSW_ULFxMAG_2FSW_VFMxAUX_1BSW_VOBS_1M_2_SW_VOBS_4M_2_SW_WHIxEVT_2_

SW_FAC_LLS_2F

Full product name
Field-aligned currents (dual-satellite A-C, local least-squares method)

Description

Time-series of field-aligned current (FAC) and radial current (IRC) densities along the orbit using the dual-satellite local least-squares (LLS) method. IRC density is obtained by applying the Ampere's law on four-point configurations, formed along the orbit by combining satellite positions from Swarm A and Swarm C. IRC density is provided along the whole orbit, except in the region close to the orbital cross-point, when the geometry of the four-point configurations becomes too elongated (i.e. for absolute values in latitude > approx. 86.6° during Swarm nominal orbit configuration). The FAC density, derived from IRC density by considering the local inclination of the magnetic field, can only be calculated at latitudes where the geomagnetic field inclination is > 30° or < - 30°. Note: to minimize the influence of small-scale fluctuations at each satellite and to match the scale of the magnetic perturbations with the configuration scale, the magnetic field data is filtered with a Butterworth, order 5, 20 s cut-off low-pass filter.

Data Access

  • Files
    • HTTPS (Product files): https://swarm-diss.eo.esa.int/#swarm/Level2daily/Latest_baselines/FAC/LLS/Sat_AC
    • FTP (Product files): ftp://swarm-diss.eo.esa.int/Level2daily/Latest_baselines/FAC/LLS/Sat_AC

Output variables

Variable NameData TypeDescriptionUnits
TimestampCDF_EPOCHTime, UTCmilliseconds
LatitudeCDF_DOUBLEPosition in ITRF, Latitudedegrees
LongitudeCDF_DOUBLEPosition in ITRF, Longitudedegrees
RadiusCDF_DOUBLEPosition in ITRF, Radiusm
FACCDF_DOUBLEFAC densityµA/m2
IRCCDF_DOUBLEIRC densityµA/m2
FACerrCDF_DOUBLEUncertainty of FACµA/m2
IRCerrCDF_DOUBLEUncertainty of IRCµA/m2
FlagCDF_UINT2Quality flag-

Details

Product Identifier FAC_LLS_2F
Definition Time-series of field-aligned current (FAC) and radial current (IRC) densities along the orbit using the dual-satellite local least-squares (LLS) method. IRC density is obtained by applying the Ampere’s law on four-point configurations, formed along the orbit by combining satellite positions from Swarm A and Swarm C. IRC density is provided along the whole orbit, except in the region close to the poles (i.e. for absolute values in latitude > approx. 86.6°). The FAC density, derived from IRC density by considering the local inclination of the magnetic field, can only be calculated at latitudes where the geomagnetic field inclination is > 30° or < -30°.

Note: to minimize the influence of small-scale fluctuations at each satellite and to match the scale of the magnetic perturbations with the configuration scale, the magnetic field data is filtered with a Butterworth, order 5, 20 s cut-off low-pass filter.
Input Data MAGx_LR_1B, AUXxORBCNT, x = [A,C], latest CHAOS model1 including contributions from core, lithosphere, magnetosphere and secondary currents.
Input Time Span 3 days
Spatial representation Current density estimates along the entire orbits at positions between Swarm A and Swarm C
Time representation Time-series of current densities at 1 s resolution
Units Current densities: µA/m2
Resolution Current density: 1E-6 µA/m2
Uncertainty 25 nA/m2 around ± 86.6°, decreasing towards Equator
Quality Indicator Product quality flag. The meaning of the individual bits are described below:

Bit nr. Value Meaning
1 0/1 Value is 1 when at least one absent magnetic field value at quad’s corners
2-4 0/N Number of bad magnetic field values (i.e. magnetic field components set to zero in the MAGx_LR_1B files) at quad’s corners. N = 0 - 4
5-7 0/N Number of interpolated magnetic field value at quad’s corners. Interpolated values occur when the interval of bad magnetic data is less than 4 s. N = 0 - 4
8 0/1 Value is 1 when the interval of valid magnetic data is too small for data filtering. This occurs when the interval of time-consecutive quads is < 30 s.
9 0/1 Value is 1 when the quad is too elongated / too close to the orbital cross-point. This roughly corresponds to absolute values in (quad mesocenter) geographic latitude > 86.6 deg. for Swarm nominal phase.
10 0/1 Value is 1 when the quad is too close to the Equator and the FAC density cannot be computed. This occurs when the (absolute value of) magnetic field inclination with respect to the quad plane is < 30 deg.

Examples:
  • Flag = 1 (binary 0000000001): Valid IRC estimation; FAC density could not be computed because the quad is too close to the Equator.
  • Flag = 128 (binary 0010000000): 2 bad magnetic field values at quad’s corners that were not interpolated. IRC and FAC are set to NaN.
Data Volume < 4 MB per day
Data Format CDF
Output Data
Variable Name Data Type Description Units
Timestamp CDF_EPOCH Time, UTC milliseconds
Latitude CDF_DOUBLE Position in ITRF, Latitude degrees
Longitude CDF_DOUBLE Position in ITRF, Longitude degrees
Radius CDF_DOUBLE Position in ITRF, Radius m
FAC CDF_DOUBLE FAC density µA/m2
IRC CDF_DOUBLE IRC density µA/m2
FACerr CDF_DOUBLE Uncertainty of FAC µA/m2
IRCerr CDF_DOUBLE Uncertainty of IRC µA/m2
Flag CDF_UINT2 Quality flag
Output Time Span 1 day
Update Rate daily
Latency < 1 min
Notes 1Version information of Input Data are available in the CDF global attributes.

Related resources

  • SIFACIT project
  • Validation report (TBA)
SW_FAC_LLS_2F
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