L2 (Level 2) Product Definitions
Specification of Level 2 Products
This section describes the product name convention and the product classification.
Product Name Convention
According to [AD13], Swarm product names consist of 10 digits, which are subdivided into two subfields 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 [AD13]. 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 [AD12]. Each L2 product is attributed to one of these categories.
Cat1: 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 Cat1 products require interaction with experienced scientists. The products will be processed by SCARF, and will be distributed by ESA.
Cat2: Algorithms leading to a L2 product with minimum delay with respect to the generation of the corresponding Level 1b data. The generation of Cat2 products is designed to run automatically. The Cat2 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 Cat1 magnetic products, e.g. core field model and magnetospheric model, will be derived on Fast Track. All Cat2 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 nonFast Track products a validation report is required. Validation reports are provided for each product chain (see L2 Product Overview Table). The intercomparison 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, 1Dmantle conductivity (mantle conductivity model and Cresponse), 3Dmantle conductivity (mantle conductivity model and Cresponse 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 
Cat1: Spherical harmonic model of the main (core) field and its temporal variation 
ASCII listing 
.shc 
MCO_SHA_2D 
Cat1: Spherical harmonic model of the main (core) field and its temporal variation 
ASCII listing 
.shc 
MCO_VAL_2C 
Cat1: Validation report on core magnetic field 
PDF 
.pdf 
MCO_VAL_2D 
Cat1: Validation report on core magnetic field 
PDF 
.pdf 
MCO_VAL_2_ 
Cat1: Validation report on core magnetic field 
PDF 
.pdf 
MCO_SHA_2F 
Cat1: Spherical harmonic model of the main (core) field and its temporal variation 
ASCII listing 
.shc 
MCO_SHA_2X 
Cat1: Spherical harmonic model of the main (core) field and its temporal variation 
ASCII listing 
.shc 
Lithospheric Field 
MLI_SHA_2C 
Cat1: Spherical harmonic model of the lithospheric field 
ASCII listing 
.shc 
MLI_SHA_2D 
Cat1: Spherical harmonic model of the lithospheric field 
ASCII listing 
.shc 
MLI_VAL_2C 
Cat1: Validation report on lithospheric field 
PDF 
.pdf 
MLI_VAL_2D 
Cat1: Validation report on lithospheric field 
PDF 
.pdf 
MLI_VAL_2_ 
Cat1: Validation report on lithospheric field 
PDF 
.pdf 
Mantle Conductivity 
MIN_1DM_2_ 
Cat1: 1D model of mantle conductivity 
ASCII listing 
.txt 
MCR_1DM_2_ 
Cat1: 1D Cresponse maps 
ASCII listing 
.txt 
MI1_VAL_2_ 
Cat1: Validation report on 1D mantle conductivity 
PDF 
.pdf 
MC1_VAL_2_ 
Cat1: Validation report on 1D Cresponse 
PDF 
.pdf 
External Current Systems 
MMA_SHA_2C 
Cat1: Spherical harmonic model of the largescale magnetospheric field and its Earthinduced counterpart 
CDF 
.cdf 
MMA_VAL_2C 
Cat1: Validation report magnetospheric magnetic model 
PDF 
.pdf 
MMA_SHA_2F 
Cat1: Spherical harmonic model of the largescale magnetospheric field and its Earthinduced counterpart 
CDF 
.cdf 
MIO_SHA_2C 
Cat1: Spherical harmonic model of the daily geomagnetic variation at middle latitudes (Sq) and low latitudes (EEJ) 
ASCII listing 
.txt 
MIO_SHA_2D 
Cat1: Spherical harmonic model of the daily geomagnetic variation at middle latitudes (Sq) and low latitudes (EEJ) 
ASCII listing 
.txt 
MIO_VAL_2C 
Cat1: Validation report on ionospheric magnetic model 
PDF 
.pdf 
MIO_VAL_2D 
Cat1: Validation report on ionospheric magnetic model 
PDF 
.pdf 
MIO_VAL_2_ 
Cat1: Validation report on ionospheric magnetic model 
PDF 
.pdf 
IBIxTMS_2F 
Cat2: Ionospheric bubble index 
CDF 
.cdf 
TECxTMS_2F 
Cat2: Time series of the ionospheric total electron content 
CDF 
.cdf 
FAC_TMS_2F 
Cat2: Time series of fieldaligned currents
(FACdual) 
CDF 
.cdf 
FACxTMS_2F 
Cat2: Time series of fieldaligned currents
(FACsingle) 
CDF 
.cdf 
EEFxTMS_2F 
Cat2: Equatorial Electric Field 
CDF 
.cdf 
IPDxIRR_2F 
Time series of characteristics of the plasma density and plasma irregularities along the orbit from single satellite measurements 
CDF 
.cdf 
Precise Orbit Determination 
SP3xCOM_2_ 
Cat1: time series of position and velocity of the center of mass of each satellite (reduceddynamic POD) 
ASCII listing 
.sp3 
SP3xKIN_2_ 
Cat1: time series of position of the center of mass of each satellite (kinematic POD) 
ASCII listing 
.sp3 
SP3xVAL_2_ 
Cat1: Validation report for SP3xCOM_2_ 
PDF 
.pdf 
ACCxPOD_2_ 
Cat1: Time series of nongravitational accelerations estimated by POD 
CDF 
.cdf 
Accelerometry 
ACCxCAL_2_ 
Cat1: Corrected and calibrated accelerometer observations 
CDF 
.cdf 
ACCxVAL_2_ 
Cat1: Validation report for ACCxCAL_2_ 
PDF 
.pdf 
Magnetic Forcing of the Upper Atmosphere 
ACCx_AE_2_ 
Cat1: Time series of calibrated and preprocessed accelerometer observations and of aerodynamic accelerations 
CDF 
.cdf 
DNSxPOD_2_ 
Cat1: time series of neutral thermospheric density from precise orbit determination data only 
CDF 
.cdf 
DNSxACC_2_ 
Cat1: time series of neutral thermospheric density 
CDF 
.cdf 
Gravity Field 
EGF_SHA_2_ 
Cat1: Monthly gravity field of the Earth 
ASCII listing 
.gcf 
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Level 2 Products
Core Field
⇒ L2 Cat1: 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) [AD15] 
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 Cat1: MCO_SHA_2D
Product identifier 
MCO_SHA_2D 
Definition 
Spherical harmonic model of the main (core) field and its temporal variation 
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) [AD15] 
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 Cat1: 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 Cat1: 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 Cat1: 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 Cat1: 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 [AD15] 
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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⇒ L2 Cat1: MCO_SHA_2X
Product identifier 
MCO_SHA_2X 
Definition 
Spherical harmonic model of the main (core) field and its temporal variation 
Input Data 
MAGx_LR_1B, AUX_DST_2_, AUX_KP__2_, AUX_IMF_2_, AUX_OBS_2_ 
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 

Quality indicator 

Data volume 
~10 kB 
Data format 
ASCII table [AD15] 
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
More information can be found at
http://www.spacecenter.dk/files/magneticmodels/CHAOS6/

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Lithospheric Field
⇒ L2 Cat1: 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) [AD15] 
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 Cat1: 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) [AD15] 
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 Cat1: 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 Cat1: 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 Cat1: 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 Cat1: MIN_1DM_2_
Product identifier 
MIN_1DM_2_ 
Definition 
1D model of mantle conductivity 
Input Data 
MIN_1DMi2_, MC1_VAL_2_ 
Input Time Span 
2 years 
Spatial representation 
Conductivity distribution with respect to depth (1D 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 [AD15] 
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 1D model is foreseen as the output of the 1D frequency domain inversion 
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⇒ L2 Cat1: MCR_1DM_2_
Product identifier 
MCR_1DM_2_ 
Definition 
Global 1D Cresponses 
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 [AD15] 
Output Data 
Cresponses (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 Cat1: 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 Cat1: MC1_VAL_2_
Product identifier 
MC1_VAL_2_ 
Definition 
Validation report for 1D Cresponse 
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 Cat1: 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 
Rootmeansquare difference between models and input data (after processing to subtract nonmagnetospheric 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 timeinstant 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; rootmeansquare 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 Cat1: 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 Cat1: 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 
Rootmeansquare 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 
Rootmeansquare difference between models and input data (after processing to subtract nonmagnetospheric 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 timeinstant 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 timeseries is shorter than 1year 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; rootmeansquare 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 Cat1: 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 [AD15] 
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 Cat1: 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 [AD15] 
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 Cat1: 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 Cat1: 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 Cat1: 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 Cat2: 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 [AD5].

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 Cat2: 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 
1s time series for TEC and 1 day for DCB 
Units 
TECU (10^{16} electrons/m^{2}) 
Resolution 
1E8 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,Zcoordinates (WGS84) of the GPS satellite 
CDF_DOUBLE 
km 
LEO_Position 
X,Y,Zcoordinates (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 signaltonoise ratio or raw signal strength on L1 
CDF_DOUBLE 
No Unit 
S2 
GPS signaltonoise ratio or raw signal strength on L2 
CDF_DOUBLE 
No Unit 
Absolute_STEC 
Absolute slant TEC 
CDF_DOUBLE 
TECU 
Absolute_VTEC 
Absolute vertical TEC 
CDF_DOUBLE 
TECU 
ElevationAngle 
Elevation angle 
CDF_DOUBLE 
degree 
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 
The cadence of the TECxTMS_2F data has changed from 10s (0.1 Hz) to 1s (1 Hz) at:

20140714 06:42:59 for Swarm A

20140714 06:06:46 for Swarm B

20140714 08:15:59 for Swarm C
It is recommended to use absolute VTEC data with corresponding elevation angles of the GPS rays of at least 50°.

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⇒ L2 Cat2: FAC_TMS_2F
Product identifier 
FAC_TMS_2F 
Definition 
Time series of fieldaligned and radial current densities along the orbit using the dualsatellite method. Fieldaligned current (FAC) density is derived by the multiplication of the radial current (IRC) density with the inclination angle of the geomagnetic field. The fieldaligned 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 dualsatellite method is lowpass filtered with a 3dB 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/m^{2} 
Resolution 
Current density: 1E6 µA/m^{2} 
Uncertainty 
50 nA/m^{2} for periods 10s to 90min on top of constant bias of <200nA/m^{2}, 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 FACdual (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 FACdual N can be equal to 1, 2, 3, or 4.
DigitNr. 
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 FACdual, 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 [AD5].

Data volume 
5 MB per day 
Data format 
CDF
Variable Name 
Data Type 
Descriptions 
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 
IRC 
CDF_DOUBLE 
Ionospheric radial current (IRC) 
µA/m^{2} 
IRC_Error 
CDF_DOUBLE 
uncertainty of IRC 
µA/m^{2} 
FAC 
CDF_DOUBLE 
Fieldaligned current (FAC) 
µA/m^{2} 
FAC_Error 
CDF_DOUBLE 
uncertainty of FAC 
µA/m^{2} 
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 Cat2: FACxTMS_2F
Product identifier 
FACxTMS_2F 
Definition 
Time series of fieldaligned and radial current densities along the orbit from single satellite measurements. Fieldaligned current (FAC) density is derived by the multiplication of the radial current (IRC) density with the inclination angle of the geomagnetic field. The fieldaligned 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/m^{2} 
Resolution 
Current density: 1E6 µA/m^{2} 
Uncertainty 
less than FAC_TMS_2F, 70 nA/m^{2} on top of constant bias of <200nA/m^{2}, 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 FACsingle (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 FACsingle N can be equal to 1 or 2.
DigitNr. 
Value 
Meaning 
1 
0/N 
A short (< 5 seconds) data gap occurred, which was interpolated linearly 
2 
0 
For FACsingle, 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 FACsingle, 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 [AD5].

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

Data Type 
Descriptions 
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 
IRC 
CDF_DOUBLE 
Ionospheric radial current (IRC) 
µA/m^{2} 
IRC_Error 
CDF_DOUBLE 
uncertainty of IRC 
µA/m^{2} 
FAC 
CDF_DOUBLE 
Fieldaligned current (FAC) 
µA/m^{2} 
FAC_Error 
CDF_DOUBLE 
uncertainty of FAC 
µA/m^{2} 
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 Cat2: 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 dayside equator crossing (90 minute sampling for daynight local time orbits, 45 minutes for dawndusk orbits) 
Update rate 
One output file per day 
Latency 
20 minutes 
Notes 

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⇒ L2: IPDxIRR_2F
Product identifier 
IPDxIPR_2F 
Definition 
Time series of characteristics of the plasma density and plasma irregularities along the orbit from single satellite measurements. Time series of local plasma conditions, including background density and total electron content. Data related to geomagnetic regions in the ionosphere. Indication of severity of plasma irregularities for groundbased users provided

Input data 
EFI_LP_1B, TECxTMS_2F, AOBxFAC_2F, IBIxTMS_2F, PCP – Polar Cap Products 
Input time span 
3 days 
Spatial representation 
Data provided along entire orbits at positions of SwA, SwB, and SwC 
Time representation 
1 second time series (the electron density data are downsampled to 1 second resolution; the timestamp of the electron density and TEC data are rounded to the nearest integer UTC seconds) 
Units 
See data format table 
Resolution 
Temporal data resolution of 1 second, density variations estimated at 0.5 second resolution 
Uncertainty 
N/A 
Quality indicator 
Quality flags are handed through from Level 1b and Level 2 processing which is used as input data 
Data volume 
ca.10 MB per day, per satellite 
Data format 
CDF 
Output data 
CDF file with time series
Variable Name 
Data Type 
Descriptions 
Units 
Timestamp 
CDF_EPOCH 
Time, UTC 
milliseconds 
Latitude 
CDF_DOUBLE 
Position in ITRF – Latitude 
deg 
Longitude 
CDF_DOUBLE 
Position in ITRF – Longitude 
deg 
Radius 
CDF_DOUBLE 
Position in ITRF – Radius 
m 
Ne 
CDF_DOUBLE 
Plasma density; directly copied from the Langmuir probe files 
cm^3 
Background Ne 
CDF_DOUBLE 
Background density; calculated from Ne using a percentile filter 
cm^3 
Foreground Ne 
CDF_DOUBLE 
Foreground density; calculated from Ne using a percentile filter 
cm^3 
Te 
CDF_DOUBLE 
Electron temperature; directly copied from the Langmuir probe files 
K 
PCP_flag 
CDF_INT4 
The polar cap patch flag 
 
Grad_Ne@100km 
CDF_DOUBLE 
The electron density gradient in a running window calculated via linear regression over 27 data points for the 2 Hz electron density data 
cm^3/m 
Grad_Ne@50km 
CDF_DOUBLE 
The electron density gradient in a running window calculated via linear regression over 13 data points for the 2 Hz electron density data 
cm^3/m 
Grad_Ne@20km 
CDF_DOUBLE 
The electron density gradient in a running window calculated via linear regression over 5 data points for the 2 Hz electron density data 
cm^3/m 
Grad_Ne@PCP_edge 
CDF_DOUBLE 
The linear electron density gradient calculated over the edges of a patch; nonzero only at the edges of polar cap patches 
cm^3/m 
ROD 
CDF_DOUBLE 
Rate Of change of Density 
cm^3/s 
RODI10s 
CDF_DOUBLE 
Rate Of change of Density Index (RODI) is the standard deviation of ROD over 10 seconds 
cm^3/s 
RODI20s 
CDF_DOUBLE 
Rate Of Density Index (RODI) is the standard deviation of ROD over 20 seconds 
cm^3/s 
delta_Ne10s 
CDF_DOUBLE 
Derived by subtracting Ne by its median filtered value in 10 seconds; indicates the electron density fluctuations smaller than 75 km 
cm^3 
delta_Ne20s 
CDF_DOUBLE 
Derived by subtracting Ne by its median filtered value in 20 seconds; indicates the electron density fluctuations smaller than 150 km 
cm^3 
delta_Ne40s 
CDF_DOUBLE 
Derived by subtracting Ne by its median filtered value in 40 seconds; indicates the electron density fluctuations smaller than 300 km 
cm^3 
num_GPS_satellites 
CDF_INT4 
Total number of tracked GPS satellites above 20 degrees 
 
mVTEC 
CDF_DOUBLE 
Median of VTEC from all available GPS satellites above 30 degrees 
TECU 
mROT 
CDF_DOUBLE 
Median of Rate Of TEC (ROT) from all available GPS satellites above 30 degrees 
TECU/s 
mROTI10s 
CDF_DOUBLE 
Median of Rate Of TEC Index (ROTI) from all available GPS satellites above 30 degrees. The ROTI of each satellite is the standard deviation of ROT over 10 seconds 
TECU/s 
mROTI20s 
CDF_DOUBLE 
Median of Rate Of TEC Index (ROTI) from all available GPS satellites above 30 degrees. The ROTI of each satellite is the standard deviation of ROT over 20 seconds 
TECU/s 
IBI_flag 
CDF_INT4 
Plasma Bubble Index, copied from the level2 Ionospheric Bubble Index product, IBIxTMS_2F 
 
Ionopshere_region_ flag 
CDF_INT4 
0: equator, 1: midlatitudes; 2: auroral oval; 3: polar cap 
 
IPIR_index 
CDF_INT4 
03 low, 45 medium, and > 6 high level of fluctuations in the ionospheric plasma density 
 
Ne_quality_flag 
CDF_INT4 
Quality flag for the Ne data and the derived data from Ne, e.g., background density, foreground density etc. It is a mixture of the LP and TII QFlags. It is calculated as LP_QFLAG*1000 + TII_QFLAG 
 
TEC_STD 
CDF_DOUBLE 
Standard deviation of VTEC from GPS satellites 
TECU 

Output time span 
1 day 
Update rate 
1 per day 
Latency 
10 min 
Notes 
The meanings of the PCP_flag are as follows: 0 if the plasma density measurement occurred outside a polar cap patch. 1 if the plasma density measurement occurred at one of the edges of a polar cap patch (no plasma velocity measurements are available). 2 if the plasma density measurement occurred at the leading edge of a polar cap patch. 3 if the plasma density measurement occurred at the trailing edge of a polar cap patch. 4 if the plasma density measurement occurred inside a polar cap patch proper. When no ion drift data is available, the leading and trailing edges cannot be distinguished. In this case the polar cap patch flag is set to 4 throughout the patch proper and to 1 throughout both edges 
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Precise Orbit Determination
⇒ L2 Cat1: 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 (Earthfixed) 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, SC_xDYN_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 [AD15] 
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 Cat1: SP3xKIN_2_
Product identifier 
SP3xKIN_2_ 
Definition 
Time series of kinematic position of the center of mass of each satellite in the ITRF (Earthfixed) 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, SC_xDYN_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 [AD15] 
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 Cat1: 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 Cat1: ACCxPOD_2_
Product identifier 
ACCxPOD_2_ 
Definition 
Time series of nongravitational accelerations obtained by POD 
Input data 
SP3xCOM_2_, GPSx_RO_1B, STRxATT_1B, SC_xDYN_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/s^{2 } 
Resolution 
64 bit double precision floating point number format 
Uncertainty 
10^{7} m/s^{2 }variance for alongtrack and crosstrack 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/s^{2} 
Estimated nongravitational 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 reduceddynamic 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 Cat1: 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_, SC_xDYN_1B, ACCx_PR_1B 
Input time span 
24 h 
Spatial representation 
Threedimensional time series along satellite orbit 
Time representation 
UTC 
Units 
m/s^{2} for accelerations, unitless for scale factors and flags 
Resolution 
64 bit double precision floating point number format 
Uncertainty 
0.01 scale factor for flight direction, 10^{7} m/s^{2} for alongtrack bias 
Quality indicator 
Validation report ACCxVAL_2_
Global attribute "DAILY_QUALITY_INDEX" of Type CDF_REAL, which ranges from 1.0 (good data quality) to 5.0 (bad data quality) 
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/s^{2} 
Calibrated linear acceleration (X,Y,Z) 
a_stp 
CDF_REAL8 
3 
m/s^{2} 
Step correction for linear accelerations 
a_tmp 
CDF_REAL8 
3 
m/s^{2} 
Temperature correction for linear accelerations 
a_gg 
CDF_REAL8 
3 
m/s^{2} 
Gravity gradient correction for linear accelerations 
a_aa 
CDF_REAL8 
3 
m/s^{2} 
Angular acceleration correction for linear accelerations 
a_ca 
CDF_REAL8 
3 
m/s^{2} 
Centrifugal acceleration correction for linear accelerations 
s 
CDF_REAL8 
3 
N/A 
Scale factor (time series) for linear accelerations 
b 
CDF_REAL8 
3 
m/s^{2} 
Bias for linear accelerations 
spike_index 
CDF_REAL8 
3 
m/s^{2} 
Vector indicating per axis the size of artificial spikes in 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 (xdirection is roughly alongtrack, ydirection is roughly crosstrack, zdirection is roughly nadir)
Calibration was performed against nongravitational 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 Cat1: ACCxVAL_2_
Product identifier 
ACCxVAL_2_ 
Definition 
Validation report for measured, modeled and POD accelerations ACCxCAL_2_, ACCxDISi2_ 
Input data 
ACCxDISi2_, ACCxCAL_2_, ACCxPOD_2_, SC_xDYN_1B_, ACCx_PR_1B_, MODx_SC_1B_ 
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 Cat1: ACCx_AE_2_
Product identifier 
ACCx_AE_2_ 
Definition 
Time series of calibrated accelerometer data, preprocessed to represent external nongravitational forces and aerodynamic accelerations 
Input data 
SC_xDYN_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 
Timeseries 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/s^{2} 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 TDAxVAL_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/s^{2} 
Nongravitational acceleration from accelerometer and GPS receiver (X ≈ alongtrack) 
acc_ro_obs 
CDF_REAL8 
1 
m/s^{2} 
Aerodynamic accelerations (X ≈ alongtrack) 

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 Cat1: 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 nongravitational accelerations based on precise orbit determination data only (ACCxPOD_2_) 
Input data 
MODx_SC_1B, STRxATT_1B, SC_xDYN_1B, ACCx_FMi2_, GPSx_RO_1B, ACCxPOD_2_ 
Input time span 
24 hr 
Spatial representation 
Timeseries 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/m^{3} 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/m^{3} 
Density derived from GPS accelerations 
density_orbitmean 
CDF_REAL8 
1 
kg/m^{3} 
Orbitaverage 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 nongravitational acceleration component along the spacecraft Xaxis. The following processing steps have been performed:
 Modelled radiation pressure accelerations have been subtracted from the full nongravitational 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 gassurface 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 Cat1: DNSxACC_2_
Product identifier 
DNSxACC_2_ 
Definition 
Thermospheric density at the satellite location 
Input data 
STRxATT_1B, SC_xDYN_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 
Timeseries 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/m^{3} 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 TDAxVAL_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/m^{3} 
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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Gravity Field
⇒ L2 Cat1: EGF_SHA_2_
Product identifier 
EGF_SHA_2_ 
Definition 
Monthly gravity field of the Earth 
Input data 
GPSA_RO_1B, GPSB_RO_1B, GPSC_RO_1B, STRAATT_1B, STRBATT_1B, STRCATT_1B 
Input time span 
1 calendar month 
Spatial representation 
Spherical harmonic coefficients 
Time representation 
Monthly average of Earth's gravity field, i.e. with an implicit epoch located at the middle of the calendar month 
Units 
See output data 
Resolution 
12 significant digits in scientific notation 
Uncertainty 
Typically 12 mm geoid height or 12 cm Equivalent Water Height discrepancy w.r.t. GRACE over land areas during low solar activity periods, considering Gaussian smoothing with 750km spherical cap radius 
Quality indicator 
RMS over ocean areas that are 6 degrees away from coast lines, after removing longterm trend, annual and semiannual variations estimated from monthly unweighted averages of numerous GRACE models (AIUB02, CSR05, GRGS03, ITSG14, GFZ05a, JPL05 and TNJ01) 
Data volume 
20 Kb 
Data format 
ASCII file with Stokes Coefficients following the ICGEMformat (http://icgem.gfzpotsdam.de/ICGEMFormat2011.pdf) 
Output data 
Degree, order, cosine coefficient, sine coefficient (columns 5 and 6 set to zero) 
Output time span 
1 calendar month 
Update rate 
Quarterly 
Latency 
5 months 
Notes 
 Stokes coefficients available up to degree 40
 No smoothing applied
 GRACE comparison indicates that there is little useful geophysical signal above roughly degree 12, i.e. it suggest the signaltonoise ratio drops below 1 at those degrees and above
 Further product details in Swarm ITT1.1 TN01

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Processing Chains of Level 2 Products
Figure 1: L2 chain
Figure 2: L2 processing chains which result in magnetic L2 products
Figure 3: L2 processing chains that result in precise orbits and thermosphere L2 products
Figure 4: L2 processing chains related to the Earth environment and space weather (Cat2 products)
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