Minimize L2 (Level 2) Product Definitions
Contents

Specification of Level 2 Products

This section describes the product name convention and the product classification.

Product Name Convention

According to [AD-13], Swarm product names consist of 10 digits, which are subdivided into two sub-fields as follows: TTTTTTTTTT = FFFFDDDDDD, where FFFF = File Category and DDDDDD = Semantic Descriptor.

For L2 products FFFF = FFFx, where FFF describes the product type (e.g. MCO - Magnetic Core Field) and for the single satelitte x = A, B or C for Swarm A, Swarm B, or Swarm C, respectively. If the product is derived from (available for) the satellite constellation (e.g. A and C) x = _.

The Semantic Descriptor DDDDDD = DDDy2z. DDD provides a description which is specific for each product, for example TMS for time series or SHA for spherical harmonics and y = _.

The last two digits describe the product level [AD-13]. Therefore digit 9 is always 2, identifying the product as a L2 product. The last digit z indicates the origin or the purpose of the product. This applies especially when different chains lead to the same science product. This last digit z can be:

C derived from Comprehensive Inversion
D derived from dedicated chain
F Fast Track product
E Extended, only applied for extended lithospheric field maps (MLI_SHA_2E)
_ Only one chain has been identified to lead to this product type
a Product derived from candidate chain a (only applied for mantle conductivity products - derived in the frequency domain)
b Product derived from candidate chain b (only applied for mantle conductivity products - derived in the time domain)

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Product Classification

L2 product Categories (Cat) have been defined in [AD-12]. Each L2 product is attributed to one of these categories.

Cat-1: Complex algorithms contributing to the generation of a L2 product of the various sources of the Earth's magnetic field, of thermospheric products, and for Precise Orbit determination. The generation of Cat-1 products require interaction with experienced scientists. The products will be processed by SCARF, and will be distributed by ESA.

Cat-2: Algorithms leading to a L2 product with minimum delay with respect to the generation of the corresponding Level 1b data. The generation of Cat-2 products is designed to run automatically. The Cat-2 products will be generated and distributed by ESA.

Fast Track products: The validation is performed by means of an internal quality check in the algorithms of each of these products, and the quality of the product is provided, e.g., by a quality flag. Fast Track products are released without a validation report. The Cat-1 magnetic products, e.g. core field model and magnetospheric model, will be derived on Fast Track. All Cat-2 products are Fast Track products. For all Fast Track products, the last letter of the product name is F (see Product Name Convention).

Validation Reports: For non-Fast Track products a validation report is required. Validation reports are provided for each product chain (see L2 Product Overview Table). The inter-comparison between products of two chains in one product family (e.g. MCO_SHA_2D and MCO_SHA_2C) will be released in one validation report (e.g MCO_VAL_2_). Validation report products exist for following product families (e.g.): core field models, lithospheric field models, ionospheric models, magnetosphere models, 1D-mantle conductivity (mantle conductivity model and C-response), 3D-mantle conductivity (mantle conductivity model and C-response maps), precise orbit determination, and thermospheric winds and density.

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Level 2 Product Overview

Complete information about the Swarm Level 2 products can be found in the following document: "Product specification for L2 Products and Auxiliary Products".

More information about Science Objectives can be found on the Mission Overview web page.

Science Objective Product Name Description Format Extension
Core Field MCO_SHA_2C Cat-1: Spherical harmonic model of the main (core) field and its temporal variation ASCII listing (SHC) .shc
MCO_SHA_2D Cat-1: Spherical harmonic model of the main (core) field and its temporal variation ASCII listing (SHC) .shc
MCO_VAL_2C Cat-1: Validation report on core magnetic field PDF .pdf
MCO_VAL_2D Cat-1: Validation report on core magnetic field PDF .pdf
MCO_VAL_2_ Cat-1: Validation report on core magnetic field PDF .pdf
MCO_SHA_2F Cat-1: Spherical harmonic model of the main (core) field and its temporal variation ASCII listing (SHC) .shc
Lithospheric Field MLI_SHA_2C Cat-1: Spherical harmonic model of the lithospheric field ASCII listing (SHC) .shc
MLI_SHA_2D Cat-1: Spherical harmonic model of the lithospheric field ASCII listing (SHC) .shc
MLI_VAL_2C Cat-1: Validation report on lithospheric field PDF .pdf
MLI_VAL_2D Cat-1: Validation report on lithospheric field PDF .pdf
MLI_VAL_2_ Cat-1: Validation report on lithospheric field PDF .pdf
Mantle Conductivity MIN_1DM_2_ Cat-1: 1D model of mantle conductivity ASCII listing .txt
MCR_1DM_2_ Cat-1: 1D C-response maps ASCII listing .txt
MI1_VAL_2_ Cat-1: Validation report on 1D mantle conductivity PDF .pdf
MC1_VAL_2_ Cat-1: Validation report on 1D C-response PDF .pdf
External Current Systems MMA_SHA_2C Cat-1: Spherical harmonic model of the large-scale magnetospheric field and its Earth-induced counterpart CDF .cdf
MMA_VAL_2C Cat-1: Validation report magnetospheric magnetic model PDF .pdf
MMA_SHA_2F Cat-1: Spherical harmonic model of the large-scale magnetospheric field and its Earth-induced counterpart CDF .cdf
MIO_SHA_2C Cat-1: Spherical harmonic model of the daily geomagnetic variation at middle latitudes (Sq) and low latitudes (EEJ) ASCII listing .txt
MIO_SHA_2D Cat-1: Spherical harmonic model of the daily geomagnetic variation at middle latitudes (Sq) and low latitudes (EEJ) ASCII listing .txt
MIO_VAL_2C Cat-1: Validation report on ionospheric magnetic model PDF .pdf
MIO_VAL_2D Cat-1: Validation report on ionospheric magnetic model PDF .pdf
MIO_VAL_2_ Cat-1: Validation report on ionospheric magnetic model PDF .pdf
IBIxTMS_2F Cat-2: Ionospheric bubble index CDF .cdf
TECxTMS_2F Cat-2: Time series of the ionospheric total electron content CDF .cdf
FAC_TMS_2F Cat-2: Time series of field-aligned currents
(FAC-dual)
CDF .cdf
FACxTMS_2F Cat-2: Time series of field-aligned currents
(FAC-single)
CDF .cdf
EEFxTMS_2F Cat-2: Equatorial Electric Field CDF .cdf
Precise Orbit Determination SP3xCOM_2_ Cat-1: time series of position and velocity of the center of mass of each satellite (reduced-dynamic POD) ASCII listing (SP3) .sp3
SP3xKIN_2_ Cat-1: time series of position of the center of mass of each satellite (kinematic POD) ASCII listing (SP3) .sp3
SP3xVAL_2_ Cat-1: Validation report for SP3xCOM_2_ PDF .pdf
ACCxPOD_2_ Cat-1: Time series of non-gravitational accelerations estimated by POD CDF .cdf
Accelerometry ACCxCAL_2_ Cat-1: Corrected and calibrated accelerometer observations CDF .cdf
ACCxVAL_2_ Cat-1: Validation report for ACCxCAL_2_ PDF .pdf
Magnetic Forcing of the Upper Atmosphere ACCx_AE_2_ Cat-1: Time series of calibrated and pre-processed accelerometer observations and of aerodynamic accelerations CDF .cdf
DNSxPOD_2_ Cat-1: time series of neutral thermospheric density from precise orbit determination data only CDF .cdf
DNSxWND_2_ Cat-1: time series of neutral thermospheric density and wind speed CDF .cdf

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Level 2 Products

Core Field

⇒ L2 Cat-1: MCO_SHA_2C
Product identifier MCO_SHA_2C
Definition Spherical harmonic model of the main (core) field and its temporal variation
Input Data MCO_SHAi2C, MCO_VAL_2_
Input Time Span All available quiet time observations from the mission
Spatial representation Spherical Harmonics up to degree 18
Time representation Snapshot models, based on order 5 splines with 6 months knots spacing
Units nT
Resolution 1 pT
Uncertainty Refer to quality report
Quality indicator Statistics of data misfit provided in validation report
Data volume ~10 kB
Data format ASCII table (SHC) [AD-15]
Output Data Gauss coefficients
Output time span As input time span but with some extrapolations
Update rate First after 1 year, updated every year
Latency 1.5 months
Notes  

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⇒ L2 Cat-1: MCO_SHA_2D
Product identifier MCO_SHA_2D
Definition Spherical harmonic model of the core field
Input Data MCO_SHAi2D, MCO_VAL_2_
Input Time Span Nominal minimum of 1 year up to the full Swarm data span
Spatial representation Spherical Harmonics up to degree 18
Time representation Snapshot models (corresponding to 1/2 year knot separation and order 6 splines)
Units nT
Resolution 1 pT
Uncertainty Refer to quality report
Quality indicator Statistics of data misfit, power spectra etc. provided in validation report
Data volume ~10 kB
Data format ASCII table (SHC) [AD-15]
Output Data Gauss coefficients
Output time span Time span same as for input
Update rate 1 per year
Latency 6 weeks
Notes The model accuracy strongly depends on the LT offset between the A and C satellite pair and the satellite B

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⇒ L2 Cat-1: MCO_VAL_2C
Product identifier MCO_VAL_2C
Definition Validation report for core field model from CI chain
Input Data MCO_SHAiC, MCO_VALi2C, AUX_OBS_2_, AUX_IGR_2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate First after 1 year, updated every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MCO_VAL_2D
Product identifier MCO_VAL_2D
Definition Validation report for core field model from dedicated chain
Input Data MCO_SHAi2D, MCO_VALi2D, AUX_OBS_2_, AUX_IGR_2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate 1 per year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MCO_VAL_2_
Product identifier MCO_VAL_2_
Definition Comparative validation report for core field models
Input Data MCO_SHA_2C, MCO_SHA_2D, MCO_VAL_2C, MCO_VAL_2D, AUX_OBS_2_, AUX_IGR_2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate Each time both, MCO_SHA_2C and MCO_SHA_2D have been released
Latency 1 month
Notes  

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⇒ L2 Cat-1: MCO_SHA_2F
Product identifier MCO_SHA_2F
Definition Spherical harmonic model of the main (core) field and its temporal variation
Input Data MAGx_LR_1B, AUX_IGR_2_, AUX_COR_2_, AUX_LIT_2_, AUX_DST_2_, AUX_KP__2_, AUX_IMF_2_. Optional: MMA_SHAi2C, MMA_SHA_2F, MIN_1DMi2_
Input Time Span Minimum of 4 months
Spatial representation Spherical Harmonics up to degree 18
Time representation Snapshot models
Units nT
Resolution 1 pT
Uncertainty Refere to quality report
Quality indicator Statistics of data misfit, power spectra etc. provided in validation report
Data volume ~10 kB
Data format ASCII table [AD-15]
Output Data Gauss coefficients
Output time span and resolution Time span: Minimum 4 months
Time resolution: corresponding to 3 month knots separation and order 2 splines
Update rate First after 4 month, afterwards update is three months (if granted by data quality).
Latency 1 week
Notes Assumed updated rate is three month

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Lithospheric Field

⇒ L2 Cat-1: MLI_SHA_2C
Product identifier MLI_SHA_2C
Definition Spherical harmonic model of the lithospheric field
Input Data MLI_SHAi2C, MLI_VAL_2_
Input Time Span All available quiet time observations from the mission
Spatial representation Spherical Harmonics from degree 16 to 150
Time representation Snapshot
Units nT
Resolution 1 pT
Uncertainty Refer to product quality report
Quality indicator Statistics of data misfits provided in validation report
Data volume ~0.5 MB
Data format ASCII table (SHC) [AD-15]
Output Data Gauss coefficients
Output time span N/A (lithospheric field is considered constant over the analysed time range)
Update rate First after 1 year, updated every year
Latency 1.5 months
Notes  

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⇒ L2 Cat-1: MLI_SHA_2D
Product identifier MLI_SHA_2D
Definition Spherical harmonic model of the lithospheric field
Input Data MLI_SHAi2D, MLI_VAL_2_
Input Time Span One to four years of full Swarm data set
Spatial representation Spherical Harmonics from degree 16 to 150
Time representation Snapshot
Units nT
Resolution 1 pT
Uncertainty Refer to product quality report
Quality indicator Statistics of data misfits provided in validation report
Data volume ~0.5 MB
Data format ASCII table (SHC) [AD-15]
Output Data Gauss coefficients
Output time span N/A (lithospheric field is considered constant over the analysed time range)
Update rate One model every year
Latency One month
Notes  

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⇒ L2 Cat-1: MLI_VAL_2C
Product identifier MLI_VAL_2C
Definition Validation report for lithospheric field model from CI chain
Input Data MLI_SHAi2C, MLI_VALi2C, AUX_LIT_2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate First after 1 year, updated every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MLI_VAL_2D
Product identifier MLI_VAL_2
Definition Validation report for lithospheric field model from dedicated
Input Data MLI_SHAi2D, MLI_VALi2D, AUX_LIT_2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate One model every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MLI_VAL_2_
Product identifier MLI_VAL_2_
Definition Comparison validation report for lithospheric field model
Input Data MLI_SHA_2C, MLI_SHA_2D, MLI_SHA_2E, MLI_VAL_2C, MLI_VAL_2D, MLI_VAL_2E, AUX_LIT_2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate Each time both, MLI_SHA_2C , MLI_SHA_2D and MLI_SHA_2D have been released
Latency 1 month
Notes  

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Mantle Conductivity

⇒ L2 Cat-1: MIN_1DM_2_
Product identifier MIN_1DM_2_
Definition 1-D model of mantle conductivity
Input Data MIN_1DMi2_, MC1_VAL_2_
Input Time Span 2 years
Spatial representation Conductivity distribution with respect to depth (1-D layered model of the Earth)
Time representation N/A
Units Kilometers (for layer radii), Siemens per meter (for conductivities)
Resolution N/A
Uncertainty Refer to product quality report
Quality indicator N/A
Data volume A few Kb
Data format ASCII listing [AD-15]
Output Data Conductivities within the layer, and radii of the top of the layer
Output time span N/A
Update rate First version after 2 years, update every year
Latency 1 month
Notes This 1-D model is foreseen as the output of the 1-D frequency domain inversion

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⇒ L2 Cat-1: MCR_1DM_2_
Product identifier MCR_1DM_2_
Definition Global 1D C-responses
Input Data MCR_1DMi2_, MC1_VAL_2_
Input Time Span 2 years
Spatial representation N/A
Time representation N/A
Units km
Resolution N/A
Uncertainty Refer to product quality report
Quality indicator Uncertainties and squared coherencies coming from signal processing
Data volume A few Kb
Data format ASCII listing [AD-15]
Output Data C-responses (real and imaginary parts), their uncertainties and squared coherences on a set of periods
Output time span and resolution N/A
Update rate First version after 2 years, update every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MI1_VAL_2_
Product identifier MI1_VAL_2_
Definition Validation report for 1D mantle conductivity
Input Data MIN_1DMi2_, MI1_VALi2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate First version after 2 years, update every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MC1_VAL_2_
Product identifier MC1_VAL_2_
Definition Validation report for 1D C-response
Input Data MCR_1DMi2_, MC1_VALi2_
Data volume < 1 Mb per day
Data format PDF
Output Data PDF file
Update rate First version after 2 years, update every year
Latency 1 month
Notes  

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External Current Systems

⇒ L2 Cat-1: MMA_SHA_2C
Product identifier MMA_SHA_2C
Definition Spherical harmonic representation of the large scale magnetospheric field and of its induced counterpart
Input data MMA_SHAi2C, MMA_VAL_2_
Input time span All available quiet time observations from the mission
Spatial representation Spherical Harmonics of degree and order at least 1 for the external field and of degree and order at least 5 for its Earth induced counterpart
Time representation Time series
Units nT
Resolution ≤ 1 pT
Uncertainty Refer to product quality report
Quality indicator Statistics of data misfit provided in the validation report
Data volume ~2 MB/year
Data format

CDF

Various temporal resolutions may be employed for various external and internal coefficients, hence a number of CDF variable groups are used to store external (named "...qs_N") respectively internal (named "...gh_N") coefficients. Note: the temporal resolutions for the various groups of external and internal coefficients are usually not identical.

Name Type Dim Unit Contents
t_qs_1 CDF_EPOCH 1 ms Time instants of external Gauss coefficients q (cosine) and s (sine)
qs_1 CDF_DOUBLE 1 nT External Gauss coefficients q (cosine) and s (sine) in dipole frame corresponding to time instants t_qs_1
dqs_1 CDF_DOUBLE 1 nT Formal error estimate for qs_1
nm_qs_1 CDF_INT2 1 - First column: vector of spherical harmonic degrees of the coefficients qs_1.

 

Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients q (cosine) while negative values denote coefficients s (sine)

t_qs_2 CDF_EPOCH 1 ms Time instants of external Gauss coefficients q (cosine) and s (sine)
qs_2 CDF_DOUBLE 2 nT External Gauss coefficients q (cosine) and s (sine) in dipole frame corresponding to time instants t_qs_2
dqs_2 CDF_DOUBLE 2 nT Formal error estimate for qs_2
nm_qs_2 CDF_INT2 2 - First column: vector of spherical harmonic degrees of the coefficients qs_2.

Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients q (cosine) while negative values denote coefficients s (sine)

t_gh_1 CDF_EPOCH 1 ms Time instants of induced Gauss coefficients g (cosine) and h (sine)
gh_1 CDF_DOUBLE 1 nT Internal induced Gauss coefficients g (cosine) and h (sine) in dipole frame
dgh_1 CDF_DOUBLE 1 nT Formal error estimate for gh_1
nm_gh_1 CDF_INT2 1 - First column: vector of spherical harmonic degrees of the coefficients gh_1.

Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients g (cosine) while negative values denote coefficients h (sine)

t_gh_2 CDF_EPOCH 1 ms Time instants of induced Gauss coefficients g (cosine) and h (sine)
gh_2 CDF_DOUBLE 2 nT Internal induced Gauss coefficients g (cosine) and h (sine) in dipole frame
dgh_2 CDF_DOUBLE 2 nT Formal error estimate for gh_2
nm_gh_2 CDF_INT2 2 - First column: vector of spherical harmonic degrees of the coefficients gh_2.

Second column: vector of spherical harmonic orders. Nonnegative values denote coefficients g (cosine) while negative values denote coefficients h (sine)

t_qual CDF_EPOCH 1 ms Time instants of quality information (rms, n_data, and q_flag).
rms CDF_DOUBLE 2 nT Root-mean-square difference between models and input data (after processing to subtract non-magnetospheric sources) in dipole frame, for the time instants indicated by t_qual

First column: RMS difference in radial direction. Second column: RMS difference in theta direction. Third column: RMS difference in phi direction.

n_data CDF_UINT2 2 - Number of data used at each time-instant from each satellite.

First column: Number of data from SWARM A. Second column: Number of data from SWARM B. Third column: Number of data from SWARM C.

Output data Time series of external and induced SH coefficients in dipole coordinate frame; root-mean-square differences between (processed) input data and models; number of data from each satellite used for each model; quality flag
Output time span Time span as input
Update rate First after 1 year, updated every year
Latency 1.5 months
Notes  

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⇒ L2 Cat-1: MMA_VAL_2C
Product identifier MMA_VAL_2C
Definition Validation report for magnetospheric field model from CI chain
Input data MMA_SHAi2C, MMA_SHA_2F, MMA_VALi2C
Data volume < 1 Mb per day
Data format PDF
Output data PDF file
Update rate First after 1 year, updated every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MMA_SHA_2F
Product identifier MMA_SHA_2F
Definition Spherical harmonic representation of the large scale magnetospheric field and its induced counterpart
Input data MAGx_LR_1B, AUX_IGR_2_, AUX_COR_2_, MCO_SHA_2F, MCO_SHA_2C, MCO_SHA_2D, AUX_LIT_2_, MLI_SHA_2C, MIO_SHA_2C, AUX_F10_2_, AUX_IMF_2F, AUX_DST_2_, AUX_KP__2_, AUX_OBS_2_
Input time span Full Swarm data set covering at least 30 days
Spatial representation Degree 1 spherical Harmonics for the external and internally induced fields
Time representation Snapshot values 1.5 hours apart.
Units See variable ‘Units' in ‘Data format', below.
Resolution See variable ‘Type' in ‘Data format', below.
Uncertainty Overall uncertainty will include contributions from uncertainties in the Input Data, which are not calculated here. Estimates of the uncertainty resulting from the modeling process after the Input Data has been processed can be obtained from the ‘rms' output variable.
Quality indicator Root-mean-square difference between model and (processed) input data; number of data used per model; quality flag.
Data volume ~5 MB/year
Data format CDF
Name Type Dim Unit Contents
t_qs CDF_EPOCH 1 ms Time instants (CDFEPOCH) of external Gauss coefficients q (cosine) and s (sine)
qs_geo CDF_DOUBLE 2 nT External Gauss coefficients q (cosine) and s (sine) in Geographic frame
qs_sm CDF_DOUBLE 2 nT External Gauss coefficients q (cosine) and s (sine) in Solar Magnetic frame
nm_qs CDF_INT2 2 - First column: vector of spherical harmonic degrees of the coefficients qs_geo and qs_sm. Nonnegative values denote coefficients q (cosine) while negative values denote coefficients s (sine)

Second column: vector of spherical harmonic orders

t_gh CDF_EPOCH 1 ms Time instants (CDFEPOCH) of induced Gauss coefficients g (cosine) and h (sine)
gh_geo CDF_DOUBLE 2 nT Internal induced Gauss coefficients g (cosine) and h (sine) in Geographic frame
gh_sm CDF_DOUBLE 2 nT Internal induced Gauss coefficients g (cosine) and h (sine) in Solar Magnetic frame
nm_gh CDF_INT2 2 - First column: vector of spherical harmonic degrees of the coefficients gh_geo and gh_sm. Nonnegative values denote coefficients g (cosine) while negative values denote coefficients h (sine)

Second column: vector of spherical harmonic orders

t_qual CDF_EPOCH 1 ms Time instants (CDFEPOCH) of quality information (rms, n_data, and q_flag).
rms CDF_DOUBLE 2 nT Root-mean-square difference between models and input data (after processing to subtract non-magnetospheric sources) in geographic frame.

First column: RMS difference in radial direction. Second column: RMS difference in theta direction. Third column: RMS difference in phi direction.

n_data CDF_UINT2 2 - Number of data used at each time-instant from each satellite.

First column: Number of data from SWARM A. Second column: Number of data from SWARM B. Third column: Number of data from SWARM C.

q_flag CDF_UINT1 1 - Product quality flag. Value of zero indicates good quality / no issues. The meaning of the individual bits are described below:
Bit Set if
1 Input time-series is shorter than 1-year filter used to separate internal and external coefficients. This is unavoidable at the start of the mission.
2 Internal/external separation filter has at least one bad/missing datum. This is not necessarily serious (check n_data, above and bits 3 and 4, below).
3 total n_data for this model is < 90% of the expected maximum available.
4 Internal/external separation filter has at least one bad/missing datum amongst the most recent (five) where it is most sensitive.

Example: decimal ‘9' means bits ‘1' and ‘4' set.

Output data Time series of external and induced SH coefficients in Solar Magnetic and Geographic coordinate frames; root-mean-square differences between (processed) input data and models; number of data from each satellite used for each model; quality flag.
Output time span 1 day
Update rate Daily
Latency < 1 day
Notes  

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⇒ L2 Cat-1: MIO_SHA_2C
Product identifier MIO_SHA_2C
Definition Spherical harmonic representation of the daily geomagnetic variations at mid and low latitudes (Sq and EEJ)
Input Data MIO_SHAi2C, MIO_VAL_2_
Input time span All available quiet time observations from the mission
Spatial representation Spherical Harmonics up to degree 60 and order 12 in dipole coordinates
Time representation Fourier Series, seasonal and daily periodicity
Units nT
Resolution 1 pT
Uncertainty Refer to product quality report
Quality indicator Statistics of data misfit provided in the validation report
Data volume ~130 kB
Data format ASCII listing [AD-15]
Output data Coefficients of SH model in dipole coordinates, with seasonal and diurnal periodicity
Output time span N/A
Update rate First after 1 year, updated every year
Latency 1.5 months
Notes  

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⇒ L2 Cat-1: MIO_SHA_2D
Product identifier MIO_SHA_2D
Definition Spherical harmonic representation of the daily geomagnetic variations at mid and low latitudes (Sq and EEJ)
Input data MIO_SHAi2D, MIO_VAL_2_
Input time span 3 months to 1 year, to be confirmed and aligned to update rate
Spatial representation Spherical Harmonics up to degree 60 and order 12 in dipole coordinates
Time representation Fourier Series, seasonal and daily periodicity
Units nT
Resolution 1 fT
Uncertainty Refer to product quality report
Quality indicator Statistics of data misfits provided in the validation report
Data volume ~ 3.5 Mo'
Data format ASCII listing [AD-15]
Output data Coefficients of SH model in dipole coordinates, with seasonal and diurnal periodicity
Output time span N/A
Update rate First after 6 months, 1 year, and update every year
Latency 1.5 months
Notes  

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⇒ L2 Cat-1: MIO_VAL_2C
Product identifier MIO_VAL_2C
Definition Validation report for ionospheric field model from CI chain
Input data MIO_SHAi2C, MIO_VALi2C
Data volume < 1 Mb per day
Data format PDF
Output data PDF file
Update rate First after 1 year, updated every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MIO_VAL_2D
Product identifier MIO_VAL_2D
Definition Validation report for ionospheric field model from dedicated chain
Input data MIO_SHAi2D, MIO_VALi2D
Data volume < 1 Mb per day
Data format PDF
Output data PDF file
Update rate First after 6 months, 1 year, and update every year
Latency 1 month
Notes  

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⇒ L2 Cat-1: MIO_VAL_2_
Product identifier MIO_VAL_2_
Definition Comparison validation report for ionospheric field model
Input data MIO_SHA_2C, MIO_SHA_2D, MIO_VAL_2C, MIO_VAL_2D
Data volume < 1 Mb per day
Data format PDF
Output data PDF file
Update rate Each time when both, MIO_SHA_2C and MIO_SHA_2D are released.
Latency 1 month
Notes  

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⇒ L2 Cat-2: IBIxTMS_2F
Product identifier IBIxTMS_2F
Definition Ionospheric bubble index
Input data MAGx_LR_1B, EFIx_PL_1B, Satellite positions, Time stamps (UTC), AUX_IGR_2F, AUX_COR_2F, AUX_LIT_2F, AUX_PMF_2F, AUX_F10_2F, AUX_DST_2F, AUX_IMF_2F, AUX_SWV_2F, AUX_PSM_2F, AUX_PGM_2F
Input time span 3 days
Spatial representation One index per data point (characterising whether the magnetic observation is affected by bubble or not.)
Time representation 1s time series
Units N/A
Resolution N/A
Uncertainty N/A
Quality indicator Flags_Bubble:
0 Quiet
1 Confirmed plasma bubble
2 Unconfirmed plasma bubble
4 Large peak in unfiltered magnetic field residuals
8 Time gap
16 Too many peaks in filtered magnetic field residuals
32 Outside equatorial orbit segment or invalid latitude/local time

Flags_B, Flags_F and Flags_q provided in [AD-5].

Data volume ~4 MB/day/satellite
Data format CDF
Variable Name Description Type Units
Timestamp Time stamp in UTC CDF_EPOCH ms
Latitude Geographic latitude CDF_DOUBLE degree
Longitude Geographic longitude CDF_DOUBLE degree
Radius Geographic radius CDF_DOUBLE m
Bubble_Index Plasma Bubble Index
0 Quiet
1 Bubble
-1 Not analyzed
CDF_INT2 No unit
Bubble_Probability

Detection probability of the plasma bubble

0 not probabale
1 very probable

The bubble probability is set to 0 by default for all data with a Flags_Bubble value of 32. The accuracy of the bubble probability is 0.2.

CDF_DOUBLE No unit
Flags_Bubble Flags related to the plasma bubble index CDF_UINT1 No unit
Flags_F Flags_F passed through from MAGx_L1_B CDF_UINT1 No unit
Flags_B Flags_B passed through from MAGx_L1_B CDF_UINT1 No unit
Flags_q Flags_q passed through from MAGx_L1_B CDF_UINT1 No unit
Output data CDF file with time series
Output time span 1 day
Latency 6 min
Update rate 1 per day
Notes  

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⇒ L2 Cat-2: TECxTMS_2F
Product identifier TECxTMS_2F
Definition Time series of the ionospheric total electron content
Input data GPS RINEX observation and navigation files (GPSX_RO_1B), Swarm satellite ephemeris (MODX_SC_1B) GPS and Swarm satellite ephemeris (AUX_GPSEPH) GPS transmitter biases(AUX_DCB_2F) Leap seconds (AUX_USLEAP)
Input time span 3 days
Spatial representation Line representation of GPS –Swarm link
Time representation 10-s time series for TEC and 1 day for DCB
Units TECU (1016 electrons/m2)
Resolution 1E-8 TECU
Uncertainty 2 TECU
Quality indicator Relative_STEC_RMS (RMS deviation between code and carrier phases) and DCB_Error
Data volume ~4 MB / day / satellite
Data format CDF
Variable Name Description Type Unit
Timestamp Time stamp in UTC CDF_EPOCH ms
Latitude Geographic latitude CDF_DOUBLE degree
Longitude Geographic longitude CDF_DOUBLE degree
Radius Geographic radius CDF_DOUBLE km
GPS_Position X-,Y-,Z-coordinates (WGS84) of the GPS satellite CDF_DOUBLE km
LEO_Position X-,Y-,Z-coordinates (WGS84) of the LEO satellite CDF_DOUBLE m
PRN GPS satellite PRN CDF_UINT2 No Unit
L1 GPS L1 carrier phase observation CDF_DOUBLE m
L2 GPS L2 carrier phase observation CDF_DOUBLE m
P1 GPS P1 code phase observation CDF_DOUBLE m
P2 GPS P2 code phase observation CDF_DOUBLE m
S1 GPS signal-to-noise ratio or raw signal strength on L1 CDF_DOUBLE No Unit
S2 GPS signal-to-noise ratio or raw signal strength on L2 CDF_DOUBLE No Unit
Absolute_STEC Absolute slant TEC CDF_DOUBLE TECU
Relative_STEC Relative slant TEC CDF_DOUBLE TECU
Relative_STEC_RMS Root mean square error of relative slant TEC CDF_DOUBLE TECU
DCB GPS receiver differential code bias CDF_DOUBLE TECU
DCB_Error Error of the GPS receiver differential code bias CDF_DOUBLE TECU
Output data CDF file with time series
Output time span 1 day
Latency 6 min
Update rate 1 per day
Notes  

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⇒ L2 Cat-2: FAC_TMS_2F
Product identifier FAC_TMS_2F
Definition

Time series of field-aligned and radial current densities along the orbit using the dual-satellite method. Field-aligned current (FAC) density is derived by the multiplication of the radial current (IRC) density with the inclination angle of the geomagnetic field. The field-aligned current density can only be calculated at latitudes, where the magnetic field is well inclined, i.e. |I| > 30°. Near the magnetic equator for magnetic inclination angles |I| < 30° FAC values are set to NaN. The radial current density can be provided along the whole orbit, except for latitudes θ>86° (near poles), where both FAC and IRC values are set to NaN. 

Note that the magnetic field data used for the dual-satellite method is low-pass filtered with a 3-dB cutoff period of 20 s (corresponding to a wavelength of 150 km). This step is indispensable because the lateral distance between Swarm A and Swarm C has to be taken into account.

Input data MAGA_LR_1B, MAGC_LR_1B, Time stamps (UTC), AUX_IGR_2F, AUX_COR_2F, AUX_LIT_2F, AUX_PMF_2F, AUX_F10_2F, AUX_DST_2F, AUX_IMF_2F, AUX_SWV_2F, AUX_PSM_2F, AUX_PGM_2F
Input time span 3 days
Spatial representation Current density estimates along entire orbits at positions between SwA and SwC
Time representation Time series of current density, Δt=1sec
Units Current density: µA/m2
Resolution Current density: 1E-6 µA/m2
Uncertainty 50 nA/m2 for periods 10s to 90min on top of constant bias of <200nA/m2, for latitudes below 80°, gradually degrading between 80° to 86°, no values beyond 86°
Quality indicator Flags:

A table below presents the list of 10 individual and independent digits, characterizing the FAC-dual (FAC_TMS_2F) product quality. Digits from 1 to 8 report issues that may have been occurred at one or more of the measurement points used for the computation of a current density value. Digits 9 and 10 report whether the NaN values for the current density were used or not. Values N>0 mark the number of measurement points that were affected and value 0 marks not affected ones. For FAC-dual N can be equal to 1, 2, 3, or 4.

Digit-Nr. Value Meaning
1 0/N A short (< 5 seconds) data gap occurred, which was interpolated linearly
2 0/N A long (> 5 seconds) data gap occurred, which cannot be interpolated linearly, in the vicinity
3 0/N No EST (external part of AUX_DST_2F) data were available, and a default value was used for the magnetospheric field model
4 0/N No IST (external part of AUX_DST_2F) data were available, and a default value was used for the magnetospheric field model
5 0/N No solar radio flux (AUX_F10_2F) data were available, and a default value was used for the magnetospheric field model
6 0/N No interplanetary magnetic field (AUX_IMF_2F) data were available, and a default value was used for the magnetospheric field model
7 0/N No Em (merging electric field) data were available, and a default value was used for the magnetospheric field model
8 0/N No magnetospheric field coefficients (Aux_PMF_2F or Aux_PSM_2F or Aux_PGM_2F) were available, and magnetospheric field is set to 0
9 0/1 For FAC-dual, this digit is equal to 1 if latitude |θ| >86° (near geographic poles)
(IRC = NaN and FAC = NaN)
10 0/1 This digit is equal to 1 if inclination |I| < 30° (near magnetic equator)
(FAC = NaN)

Flags_B, Flags_F and Flags_q are handed through from Level 1b processing [AD-5].

Data volume 5 MB per day
Data format CDF
Variable Name Data Type Descriptions Units
Timestamp CDF_EPOCH Time, UTC milli-seconds
Latitude CDF_DOUBLE Position in ITRF, Latitude degrees
Longitude CDF_DOUBLE Position in ITRF, Longitude degrees
Radius CDF_DOUBLE Position in ITRF, Radius m
IRC CDF_DOUBLE Ionospheric radial current (IRC) µA/m2
IRC_Error CDF_DOUBLE uncertainty of IRC µA/m2
FAC CDF_DOUBLE Field-aligned current (FAC) µA/m2
FAC_Error CDF_DOUBLE uncertainty of FAC µA/m2
Flags CDF_UINT4 Flags characterizing the product quality (processing flags) -
Flags_F CDF_UINT4 Flags_F passed through from L1b and accumulated for quad points -
Flags_B CDF_UINT4 Flags_B passed through from L1b and accumulated for quad points -
Flags_q CDF_UINT4 Flags_q passed through from L1b and accumulated for quad points -
Output data CDF file with time series
Output time span 1day
Update rate 1 per day
Latency 10 min
Notes  

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⇒ L2 Cat-2: FACxTMS_2F
Product identifier FACxTMS_2F
Definition Time series of field-aligned and radial current densities along the orbit from single satellite measurements. Field-aligned current (FAC) density is derived by the multiplication of the radial current (IRC) density with the inclination angle of the geomagnetic field. The field-aligned current density can only be calculated at latitudes, where the magnetic field is well inclined, i.e. |I| > 30°. Near the magnetic equator for magnetic inclination angles |I| < 30° FAC values are set to NaN. The radial current density can be provided along the whole orbit. Scale size >7.5 km.
Input data MAGx_LR_1B, Satellite positions, Time stamps (UTC), AUX_IGR_2F, AUX_COR_2F, AUX_LIT_2F, AUX_PMF_2F, AUX_F10_2F, AUX_DST_2F, AUX_IMF_2F, AUX_SWV_2F, AUX_PSM_2F, AUX_PGM_2F
Input time span 3 days
Spatial representation Current density estimates along entire orbits at positions of SwA, SwB, and SwC.
Time representation Time series of current density, Δt=1sec
Units Current density: µA/m2
Resolution Current density: 1E-6 µA/m2
Uncertainty less than FAC_TMS_2F, 70 nA/m2 on top of constant bias of <200nA/m2, for latitudes below 80°, gradually degrading between 80° to 86°, no values beyond 86°
Quality indicator Flags:

A table below presents the list of 10 individual and independent digits, characterizing the FAC-single (FACxTMS_2F) product quality. Digits from 1 to 8 report issues that may have been occurred at one or more of the measurement points used for the computation of a current density value. Digits 9 and 10 report whether the NaN values for the current density were used or not. Values N>0 mark the number of measurement points that were affected and value 0 marks not affected ones. For FAC-single N can be equal to 1 or 2.

Digit-Nr. Value Meaning
1 0/N A short (< 5 seconds) data gap occurred, which was interpolated linearly
2 0 For FAC-single, this digit is always zero because no filtering is done
3 0/N No EST (external part of AUX_DST_2F) data were available, and a default value was used for the magnetospheric field model
4 0/N No IST (external part of AUX_DST_2F) data were available, and a default value was used for the magnetospheric field model
5 0/N No solar radio flux (AUX_F10_2F) data were available, and a default value was used for the magnetospheric field model
6 0/N No interplanetary magnetic field (AUX_IMF_2F) data were available, and a default value was used for the magnetospheric field model
7 0/N No Em (merging electric field) data were available, and a default value was used for the magnetospheric field model
8 0/N No magnetospheric field coefficients (Aux_PMF_2F or Aux_PSM_2F or Aux_PGM_2F) were available, and magnetospheric field is set to 0
9 0 For FAC-single, this digit is always equal to 0
10 0/1 This digit is equal to 1 if inclination |I| < 30° (near magnetic equator)
(FAC = NaN)

Flags_B, Flags_F and Flags_q are handed through from Level 1b processing [AD-5].

Data volume 5MB per day, per satellite
Data format CDF

Variable Name

Data Type Descriptions Units
Timestamp CDF_EPOCH Time, UTC milli-seconds
Latitude CDF_DOUBLE Position in ITRF, Latitude degrees
Longitude CDF_DOUBLE Position in ITRF, Longitude degrees
Radius CDF_DOUBLE Position in ITRF, Radius m
IRC CDF_DOUBLE Ionospheric radial current (IRC) µA/m2
IRC_Error CDF_DOUBLE uncertainty of IRC µA/m2
FAC CDF_DOUBLE Field-aligned current (FAC) µA/m2
FAC_Error CDF_DOUBLE uncertainty of FAC µA/m2
Flags CDF_UINT4 Flags characterizing the product quality (processing flags) -
Flags_F CDF_UINT4 Flags_F passed through from L1b and accumulated for quad points -
Flags_B CDF_UINT4 Flags_B passed through from L1b and accumulated for quad points -
Flags_q CDF_UINT4 Flags_q passed through from L1b and accumulated for quad points -
Output data CDF file with time series
Output time span 1day
Latency 10 min
Update rate 1 per day
Notes  

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⇒ L2 Cat-2: EEFxTMS_2F
Product identifier EEFxTMS_2F
Definition Dayside equatorial electric field
Input data MAGx_LR_1B, AUX_DST_2F, AUX_KP__2F , AUX_F10_2F, AUX_IGR_2F, AUX_COR_2F, AUX_LIT_2F, AUX_PMF_2F, AUX_PSM_2F, AUX_PGM_2F, AUX_IRZ_2F
Input time span Every dayside equator crossing ±20 minutes
Spatial representation One longitude/latitude pair (on the magnetic equator ) for each output value
Time representation Single values at time of dayside equator crossing
Units V/m
Resolution 0.1 mV/m
Uncertainty 0.1 mV/m
Quality indicator Relative error between modeled and observed current profile
Data volume < 2 kB
Data format CDF
Variable Name Type Description Units
timestamp CDF_EPOCH milliseconds elapsed since 00:00:00 January 1, 2000 UTC Milliseconds
longitude CDF_DOUBLE Geographic longitude of satellite crossing of the magnetic equator Degrees
latitude CDF_DOUBLE Geographic latitude of satellite crossing of the magnetic equator Degrees
EEF CDF_DOUBLE Estimate of the equatorial electric field V/m
RelErr CDF_DOUBLE Quality indicator of EEF estimate; relative error between modeled and observed current profile N/A
flags CDF_UINT2 Flags describing data gaps and satellite identification
Bit Description
1 EEF estimate came from Swarm satellite A data
2 EEF estimate came from Swarm satellite B data
3 EEF estimate came from Swarm satellite C data
4 Processor failed due to a too large data gap in the Level 1b input data
N/A
Output data

CDF file with time series

Output time span Continuous for entire mission. One value for each day-side equator crossing (90 minute sampling for day-night local time orbits, 45 minutes for dawn-dusk orbits)
Update rate One output file per day
Latency 20 minutes
Notes  

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Precise Orbit Determination

⇒ L2 Cat-1: SP3xCOM_2_
Product identifier SP3xCOM_2_
Definition Time series of dynamic position and velocity of the center of mass of each satellite in the ITRF (Earth-fixed) frame
Input Data GPSA_RO_1B, GPSB_RO_1B, GPSC_RO_1B, STRAATT_1B, STRBATT_1B, STRCATT_1B, MODA_SC_1B, MODB_SC_1B, MODC_SC_1B, External data from IGS, IERS, CODE
Input Time Span 30 hr (daily batches with overlap)
Spatial representation N/A
Time representation GPS time (seconds – s), time step = 10 s
Units km for position, dm/s for velocity
Resolution 1 ps for time, mm for position, 0.1 μm/s for velocity
Uncertainty 10 cm 3D for position
Quality indicator Validation report SP3xVAL_2_
Data volume < 2 Megabyte (MB) per satellite per day
Data format SP3c [AD-15]
Output Data SP3c file
Output time span 24 hr
Update rate Daily
Latency 21 days
Notes Central 24 hr of input time span will be selected for SP3 product

Quality report will be provided as separate Level 2 product

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⇒ L2 Cat-1: SP3xKIN_2_
Product identifier SP3xKIN_2_
Definition Time series of kinematic position of the center of mass of each satellite in the ITRF (Earth-fixed) frame
Input Data GPSA_RO_1B, GPSB_RO_1B, GPSC_RO_1B, STRAATT_1B, STRBATT_1B, STRCATT_1B, MODA_SC_1B, MODB_SC_1B, MODC_SC_1B, External data from IGS, IERS, CODE
Input Time Span 30 hr (daily batches with overlap)
Spatial representation N/A
Time representation GPS time (seconds – s), observation epochs
Units km for position, dm/s for velocity
Resolution 1 ps for time, mm for position, 0.1 μm/s for velocity
Uncertainty 10 cm 3D for position
Quality indicator Validation report SP3xVAL_2_
Data volume < 15 Megabyte (MB) per satellite per day
Data format SP3c [AD-15]
Output Data SP3c file
Output time span 24 hr
Update rate Daily
Latency 21 days
Notes Central 24 hr of input time span will be selected for SP3 product

Quality report will be provided as separate Level 2 product

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⇒ L2 Cat-1: SP3xVAL_2_
Product identifier SP3xVAL_2_
Definition Validation report for precise orbit solutions SP3xCOM_2_ and SP3xKIN_2_
Input Data SP3xCOM_2_, SP3xKIN_2_, ILRS Swarm tracking data, Diagnostic and statistical output from orbit determination process

 

Input Time Span 30 hr
Data volume < 20 Mb per satellite per day
Data format PDF
Output Data PDF file
Output time span 24 hr
Update rate 1 day
Latency 21 per day
Notes 30 hr time input time span includes overlaps between consecutive orbit solutions

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⇒ L2 Cat-1: ACCxPOD_2_
Product identifier ACCxPOD_2_
Definition Time series of non-gravitational accelerations obtained by POD
Input data SP3xCOM_2_, GPSx_RO_1B, STRxATT_1B, ACCx_PR_1B, External data from CODE
Input time span 30 hr (daily batches with overlap)
Spatial representation N/A
Time representation UTC (seconds – s), time step = 30 sec
Units m/s2
Resolution 64 bit double precision floating point number format
Uncertainty 10-7 m/s2 variance for along-track and cross-track directions
Quality indicator Validation report DNSxVAL_2_
Data volume < 10 Kb per satellite per day
Data format CDF
Field name Type Dimension Unit Contents
time CDF_EPOCH 1 ms Observation time
acc_pod CDF_REAL8 3 m/s2 Estimated non-gravitational accelerations (X,Y,Z)
Output data CDF file with time series of accelerations
Output time span 24 hr
Update rate 1 day
Latency 21 days
Notes

Version 0201 data is computed from GPS data using a Kalman filter approach. The reduced-dynamic orbit is used as a priori reference orbit. The level 1B accelerometer files are only used for spacecraft mass and CoG information

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Accelerometry

⇒ L2 Cat-1: ACCxCAL_2_
Product identifier ACCxCAL_2_
Definition Time series of corrected and calibrated acceleration, including all corrections and calibration parameters
Input data ACCx_PR_1B, ACCxPOD_2_, ACCxDISi2_
Input time span 24 h
Spatial representation Three-dimensional time series along satellite orbit
Time representation UTC
Units m/s2 for accelerometer biases, dimensionless for scale factors
Resolution 64 bit double precision floating point number format
Uncertainty 0.01 scale factor for flight direction, 10-7 m/s2 for along-track bias
Quality indicator Validation report ACCxVAL_2_
Data volume 15 MB per day
Data format CDF
Field name Type Dimension Unit Contents
time CDF_EPOCH 1 ms Epoch of observation (UTC)
a_cal CDF_REAL8 3 m/s2 Accelerometer biases (X,Y,Z)
a_stp CDF_REAL8 3 m/s2 Step correction for linear accelerations
a_tmp CDF_REAL8 3 m/s2 Temperature correction for linear accelerations
a_gg CDF_REAL8 3 m/s2 Gravity gradient correction for linear accelerations
a_ca CDF_REAL8 3 m/s2 Centrifugal acceleration correction for linear accelerations
s CDF_REAL8 3 N/A Scale factor (time series) for linear accelerations
b CDF_REAL8 3 m/s2 Preliminary bias for linear accelerations
flag_cor CDF_UINT4 1 N/A Flag indicating which corrections are applied
flag_val CDF_UINT4 1 N/A Flag indicating if data is valid
flag_thr CDF_UINT4 1 N/A Flag indicating if thruster activations
Output data CDF file with corrected and calibrated accelerations from the accelerometer, all corrections and calibration parameters, and flags; sampling rate is 1 Hz (accelerations are at original measurement epochs)
Output time span 1 day
Update rate 3 months
Latency 1 month
Notes All accelerations are provided in the CRF (x-direction is roughly along-track, y-direction is roughly cross-track, z-direction is roughly nadir)

Calibration was performed against non-gravitational accelerations from POD that are contained in product ACCxPOD_2_

Preliminary bias will be replaced by final bias in aerodynamic accelerations in product ACCx_AE_2_

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⇒ L2 Cat-1: ACCxVAL_2_
Product identifier ACCxVAL_2_
Definition Validation report for measured, modeled and POD accelerations ACCxCAL_2_, ACCx_FMi2_ and ACCxPOD_2_
Input data ACCxDISi2_, ACCxCAL_2_, ACCxPOD_2_, ACCx_FMi2_
Input time span Variable
Data volume – 10 MB / day
Output data PDF
Output time span Variable
Update rate 3 months
Latency 1 month

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Magnetic Forcing of the Upper Atmosphere

⇒ L2 Cat-1: ACCx_AE_2_
Product identifier ACCx_AE_2_
Definition Time series of calibrated accelerometer data, pre-processed to represent external non-gravitational forces and aerodynamic accelerations
Input data ACCx_PR_1B, STRxATT_1B, SP3xCOM_2_, ACCxCAL_2_, ACCxPOD_2_, AUX_F10_2_, AUX_KP__2_, External data from IERS
Input time span 24 hr
Spatial representation Time-series along satellite track, altitude (m), latitude (deg), longitude (deg) and local solar time (hours) available based on MODX_SC_1B
Time representation UTC (seconds – s), nominally with 10 s time step
Units nm/s2 for accelerations, s for time, m for altitude, degrees for latitude, longitude, hours for local solar time
Resolution 64 bit double precision floating point number format
Uncertainty N/A
Quality indicator Validation report TDWxVAL_2_
Data volume < 10 Mbyte per satellite per day
Data format CDF
Field name Type Dimension Unit Contents
time CDF_EPOCH 1 ms Observation time
acc_total_obs CDF_REAL8 1 m/s2 Non-gravitational acceleration from accelerometer and GPS receiver (X ≈ along-track)
acc_ro_obs CDF_REAL8 1 m/s2 Aerodynamic accelerations (X ≈ along-track)
Output data CDF file with time series
Output time span 24 hr
Update rate 1 day
Latency 21 days
Notes The applied accelerometer bias and scale factors are available in the metadata.

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⇒ L2 Cat-1: DNSxPOD_2_
Product identifier DNSxPOD_2_
Definition Thermospheric density at the satellite location along with auxiliary parameters (altitude, latitude, longitude and local solar time). Derived from non-gravitational accelerations based on precise orbit determination data only (ACCxPOD_2_)
Input data MODx_SC_1B, STRxATT_1B, ACCx_PR_1B, ACCx_FMi2_, GPSx_RO_1B, ACCxPOD_2_
Input time span 24 hr
Spatial representation Time-series along satellite track, altitude (m), latitude (deg), longitude (deg) and local solar time (hours) available based on MODx_SC_1B
Time representation UUTC (seconds – s), nominally with 30 s time step, as well as orbital averages
Units kg/m3 for density
Resolution 64 bit double precision floating point number format
Uncertainty 30% of variance from models for neutral density
Quality indicator Validation report DNSxVAL_2_
Data volume < 160 Kbyte per satellite per day
Data format CDF
Field name Type Dimension Unit Contents
time CDF_EPOCH 1 ms Time of observation
density CDF_REAL8 1 kg/m3 Density derived from GPS accelerations
density_orbitmean CDF_REAL8 1 kg/m3 Orbit-average of density derived from GPS accelerations
altitude CDF_REAL8 1 m Altitude
latitude CDF_REAL8 1 deg Geodetic latitude
longitude CDF_REAL8 1 deg Geodetic longitude
Output data CDF file with time series
Output time span 24 hr
Update rate 1 day
Latency 21 days
Notes

The density data is derived from the ACCxPOD non-gravitational acceleration component along the spacecraft X-axis. The following processing steps have been performed:

- Modelled radiation pressure accelerations have been subtracted from the full non-gravitational accelerations, to arrive at aerodynamic accelerations. Because the Kalman filter approach results in a smoothed representation of true accelerations, the radiation pressure model output has been smoothed as well, in order to avoid density jump artefacts at eclipse transitions.

- The resulting aerodynamic accelerations are converted into densities, using an aerodynamic model based on a panelised representation of the satellite. The gas-surface interaction is based on diffuse reflection, and an energy accommodation coefficient of 0.93 is used.

- The densities are multiplied by a factor of 1.32, to compensate for the observed difference in scale between the panelised aerodynamic model, and an aerodynamic model based on a more accurate representation of the geometry of the Swarm satellites. The more accurate model will be implemented in a future updated version of the data.

- The density_orbitmean field contains the mean density, taken over one orbital period, for each time step.The orbital period in seconds is provided as metadata in the CDF file.

At high altitude and low solar activity, the errors inherent in the radiation pressure model and acceleration determination using GPS data can become significant compared to the magnitude of the acceleration signal. This can result in large density errors and even negative densities. Users are advised to use the orbit mean densities in those conditions.

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⇒ L2 Cat-1: DNSxWND_2_
Product identifier DNSxWND_2_
Definition Thermospheric density at the satellite location
Input data STRxATT_1B, ACCx_PR_1B, ACCx_AE_2_, SP3_COM__2, AUX_IER_2_, AUX_AER_2_, AUX_F10_2_, AUX_KP__2_, External data from IERS
Input time span 24 hr
Spatial representation Time-series along satellite track, altitude (m), latitude (deg), longitude (deg) and local solar time (hours) available based on MODX_SC_1B
Time representation UTC (seconds – s), nominally with 10 s time step
Units kg/m3 for density, m/s for wind speed
Resolution 64 bit double precision floating point number format
Uncertainty 30% of variance from models for neutral density
Quality indicator Validation report TDWxVAL_2_
Data volume < 15 Mbyte per satellite per day
Data format CDF
Field name Type Dimension Unit Contents
time CDF_EPOCH 1 ms Observation time
altitude CDF_REAL8 1 m Observation altitude
latitude CDF_REAL8 1 deg Observation geodetic latitude
longitude CDF_REAL8 1 deg Observation geodetic longitude
local_solar_time CDF_REAL8 1 s Observation local solar time
density CDF_REAL8 1 kg/m3 Thermospheric neutral density
Output data CDF file with time series
Output time span 24 hr
Update rate 1 day
Latency 21 days
Notes  

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Processing Chains of Level 2 Products

Figure 1: L2 chain

Figure 1: L2 chain

Figure 2: Level-2 processing chains which result in magnetic Level-2 products

Figure 2: L2 processing chains which result in magnetic L2 products

Figure 3: Level-2 processing chains that result in precise orbits and thermosphere Level-2 products

Figure 3: L2 processing chains that result in precise orbits and thermosphere L2 products

Figure 4: Level-2 processing chains related to the Earth environment and space weather (Cat-2 products)

Figure 4: L2 processing chains related to the Earth environment and space weather (Cat-2 products)

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