Work Description

Date: June 27th, 2023

Dataset Title: Swarm and IGRF-13 Magnetic Field Vector Residuals Lager Than 300 nT

Dataset Creator: Yining Shi

Dataset Contact: Yining Shi yining@umich.edu

Funding: NASA grant 80NSSC20K1779 and NSF grants 1848724 and 2013433

Key Points:
- Residuals between Swarm magnetic field vector observations and Earth magnetic field models IGRF-13 larger than 300nT in northern and southern hemisphere

Methodology:
The data are Swarm L1b magnetic field vectors from Nov. 25th, 2013 to Dec. 31th, 2020. obtained from Swarm Virtual Research Environment (VRE) https://viresclient.readthedocs.io/en/latest/
13th generation International Geomagnetic Reference Field (IGRF-13) modeled Earth magnetic field vectors are estimated at Swarm satellite locations also obatined from Swarm VRE.
Magnetic field residuals are calculated as difference between Swarm Level 1b magnetic field vector observations and modeled magnetic field vectors. Magnitude of magnetic field residual and angle between Swarm observations and modeled magnetic field vectos are also calculated.
Residuals with magnitude larger than 300 nT under Dst>-50 nT are categorized by the geomagnetic northern and southern hemisphere as listed in 'Large_n.csv' and 'Large_s.csv' respectively.

Description:
Statistical study of residuals between Swarm observations and IGRF-13 geomagnetic field model larger than 300 nT in northern and southern hemisphere. Data analysis done on https://viresclient.readthedocs.io/en/latest/
These data are generated to conduct a statistical study of the locations of large residuals in the two hemispheres for a better understanding of potential error in satellite aviation application when using Earth magnetic field models like IGRF as references, as well as the energy transfer in the magnetosphere-ionosphere-thermosphere coupling.
Interhemispheric asymmetries are found in the locations of the large residuals due to the difference in geographic pole locations.

Instrument and/software specifications: Swarm VRE JupyterLab

Files contained here are:
Large_n.csv
Large_s.csv

Each csv file contains:
Timestamp,
Data flag,
Spacecraft number,
Latitude, Longitude, Radius in geocentric coordinate of the Swarm satellites;
corresponding Magnetic latitude, magnetic longitude and mangetic local time of the Swarm satellites in AACGM coordinate above 40/-40 degree latitude and CGM coordinate below.
Swarm magnetic field vector in North-East-Center (NEC) coordinate and its corresponding error 'B_NEC' and 'B_error';
mangitude of error 'B_error_mag';
IGRF magnetic field vector 'B_NEC_IGRF';
CHAOS magnetic field vector ' B_NEC_CHAOS';
Swarm-IGRF and Swarm-CHAOS residual vector 'B_NEC_res_IGRF' and 'B_NEC_res_CHAOS' and their magnitude 'B_NEC_res_IGRF_mag' and 'B_NEC_res_CHAOS_mag';
All magnetic field vectors are in nT.
Swarm, IGRF and CHAOS magnetic filed unit vector 'B_NEC_unit', 'B_IGRF_unit' and 'B_CHAOS_unit';
Swarm-IGRF and Swarm-CHAOS angle difference 'angle_IGRF' and 'angle_CHAOS' in degrees;
Kp*10 and Dst index at Timestamp;
Solar wind By and Bz in GSM coordinate 'IMF_BY_GSM' and 'IMF_BZ_GSM' in nT and solar wind speed 'IMF_V' in km/s.
The closest substorm onset to the large residual timepoint identified by Newell and Gjerloev [2011] substorm list.
Time delay between large residual timepoint and the cloest substorm onset.

Order of variables are random for each file.

Reference:Newell, P. T., and J. W. Gjerloev (2011), Substorm and magnetosphere characteristic scales inferred from the SuperMAG auroral electrojet indices, J. Geophys. Res., 116, A12232, doi:10.1029/2011JA016936.

Use and Access:
This data set is made available under a Attribution-NonCommercial 4.0 International license.