Joint Study Group

Atmospheric Coupling Studies

Led by ICCT; joint with GGOS FAGSWR and IAG Commission 4, Sub-Commission 4.3

Chair: Andres Calabia Aibar (Spain)
Vice-Chair: Binod Adhikari (Nepal)


The connection between solar drivers and the Earth’s magnetosphere, ionosphere, and thermosphere (MIT) phenomena in the upper atmosphere is very complex and dependent on many processes, including energy-absorption, ionization, and dissociation of molecules due to variable X-ray and Extreme Ultra Violet (EUV) solar radiance. Moreover, the variable solar wind plasma combined with a favorable alignment of the Interplanetary Magnetic Field (IMF) can produce auroral particle precipitation at high latitudes, causing chemical reactions and enhanced Joule heating through collisions between electrically-charged and neutral particles.

Figure 1.1. Known processes in the coupled MIT system.

Consequences of upper-atmosphere conditions on human activity underscore the necessity to better understand and predict the effects of MIT processes and coupling, and prevent from potential detrimental impacts on orbiting, aerial, and ground-based technologies. The spatial gradients of charged particles (mostly free-moving electrons in the ionosphere) can perturb the propagation of electromagnetic radio waves employed by satellite communication systems, remote sensing imaging, and Global Navigation Systems (GNSS) measurements. The upper atmospheric expansion/contraction in response to the variable solar and geomagnetic activity produces the variable aerodynamic drag on low Earth orbiting (LEO) satellites, which makes the satellite tracking difficult, decelerates LEO orbits, reduces their altitude, and shortens the lifespan of space assets. The exponential increase in space debris (including the recent destructive events of Fengyun-1C, Iridium, and Mission Shakti) also highlights the importance of orbital tracking for the prediction and avoidance of potential collisions with orbiting satellites by space debris. Finally, ground pipelines, power grids, and electronics could be influenced by the sudden changes in the magnetic field and associated current system caused by interplanetary shocks.

Unfortunately, the MIT coupling and its resulting MIT variations under different space weather conditions are still not well understood, and the existing models are incapable of predicting the MIT variability as required, in spite of the efforts to model variations, anomalies, and climatology over the last half-century. This is largely due to the lack of comprehensive approaches for calibrating the models, and the limited quantity of both observations under various conditions in both hemispheres, and comprehensive and coordinated observations of auroral particle precipitation and ion drift / field-aligned current.

The JSG1 aims to improve the understanding of the MIT coupling and its resulting MIT variations under various solar forcing conditions. In addition, waves from the lower atmosphere including atmospheric tides and planetary waves can feed into ionospheric electrodynamics, and consequently to the MIT system. Gravity waves can deposit momentum in the MIT, and change the mean state which then influences the wave propagation of larger waves. To that end, our tasks are to exploit the knowledge of the MIT processes by examining multiple types of magnetosphere, ionosphere, and thermosphere observations. The final outcome will help to enhance the predictive capability of empirical and physics-based models through interrelating and exploring dependencies of variability between essential geodetic variables.


The objectives of the JSG1 are:

  • To characterize and quantify the global modes of MIT variations associated with diurnal, seasonal, and solar wind drivers, as well as the lower atmosphere forcing and other possible contributions.
  • To determine and understand the mechanisms responsible for discrepancies between observables and predictions by present models, and explore parametrizing the effect of this mechanism.
  • To investigate and evaluate the importance of coupled processes in the MIT system based on physical laws and principles such as continuity, energy and momentum equations and solving partial differential equations.
  • To reveal the peculiarities of MIT dynamics during magnetic storms.


  • Opening a Website-Forum with information and updates concerning the coupled processes within the MIT, available bibliography and models, instructions and examples on how to use the models, and other relevant information (currently realized).
  • Working along with the 3 Joint Working Groups of the GGOS FA GSWR and other possible collaborators, e.g. IAG Commission 4, Sub-commission 4.3 (planned for future).
  • Elaboration and submission of scientific manuscripts co-authored by JSG1 members (currently realized & planned for future).
  • Elaboration of data and model products freely available for the scientific community (currently realized & planned for future).
  • Organization of a session at the forthcoming Hotine-Marussi symposium (planned for future).
  • Promotion and organization of sessions at international conferences and symposia related to Earth science such as IAG, IUGG, EGU and AGU (planned for future).


Calabia, A, and SG Jin (2020), Upper Atmospheric Characterization from Neutral and Electron Density Observations, Proceedings of International Association of Geodesy Symposia, IAGS-D-19-00063R2.
Calabia, A, and SG Jin, (2020) New modes and mechanisms of long-term ionospheric TEC variations from Global Ionosphere Maps, J. Geophys. Res. Space Phys., 125(6), doi:10.1029/2019JA027703
Calabia, A, G Tang, and SG Jin (2020), Assessment of new thermospheric mass density model using NRLMSISE-00 model, GRACE, Swarm-C, and APOD observations, J. Atmos. Solar Terrest. Phys., 199, 105207, doi: 10.1016/j.jastp.2020.105207
Calabia, A, and SG Jin (2019), Solar-flux and asymmetric dependencies of GRACE-derived thermospheric neutral density disturbances due to geomagnetic and solar wind forcing, Ann. Geophys., 37(5), 989-1003, doi: 10.5194/angeo-37-989-2019
Forbes, J, X Zhang, A Maute, and ME Hagan (2018), ZonallySymmetric Oscillations of the Thermosphere at PlanetaryWave Periods, J. Geophys. Res. Space Phys., 123, 41104128, doi: 10.1002/2018JA025258
Gao, C, SG Jin, and LL Yuan (2020), Ionospheric responses to the June 2015 geomagnetic storm from ground and LEO GNSS observations, Remote Sens., 12(14), 2200, doi: 10.3390/rs12142200
Heelis, RA, and A Maute (2020), Challenges to Understanding the Earth’s Ionosphere and Thermosphere. Journal of Geophysical Research: Space Physics, 125, e2019JA027497, doi:10.1029/2019JA027497
Lu, G, I Zakharenkova, I Cherniak, and T Dang (2020). Large‐scale ionospheric disturbances during the 17 March 2015 storm: A model‐data comparative study, J. Geophys. Res. Space Phys., 125, e2019JA027726, doi:10.1029/2019JA027726
Pedatella, NM, G Lu, and AD Richmond (2018), Effects of high-latitude forcing uncertainty on the low-latitude and midlatitude ionosphere. J. Geophys. Res. Space Phys., 123, 862-882. doi:10.1002/2017JA024683
Shah, M, A Calabia, MA Tariq, J Ahmed, A Ahmed (March 2020), Possible ionosphere and atmosphere precursory analysis related to Mw >6.0 earthquakes in Japan, Remote Sensing of Environment, 239, 111620, doi: 10.1016/j.rse.2019.111620.
Shah, M, A Ahmed, M Ehsan, M Khan, M A Tariq, A Calabia, ZU Rahman (Oct. 2020), Total electron content anomalies associated with earthquakes occurred during 1998 – 2019, Acta Astronautica, doi: 10.1016/j.actaastro.2020.06.005
Syrovatskiy, SV, Y Yasyukevich, IK Edemskiy, AM Vesnin, SV Voeykov, IV Zhivetiev (2019), Can we detect X/M/C-class solar flares from global navigation satellite system data? // Results in Physics. V. 12. P. 1004-1005. doi: 10.1016/j.rinp.2018.12.069
Tang, GS, X Li, J Cao, S Liu, G Chen, M Haijun, X Zhang, S Shi, J Sun, Y Li, and A Calabia (2020), APOD mission status and preliminary results, Sci. China Earth Sci., 63, 257-266, doi:10.1007/s11430-018-9362-6
Yasyukevich, Y, AV Kiselev, IV Zhivetiev, IK Edemskiy, SV Syrovatskii, BM Maletckii, AM Vesnin (2020), SIMuRG: System for Ionosphere Monitoring and Research from GNSS. GPS Solutions 24, 69, doi:10.1007/s10291-020-00983-2
Yasyukevich, Y, R Vasilyev, K Ratovsky, A Setov, M Globa, S Syrovatskii, A Yasyukevich, A Kiselev, A Vesnin (2020), Small-Scale Ionospheric Irregularities of Auroral Origin at Mid-latitudes during the 22 June 2015 Magnetic Storm and Their Effect on GPS Positioning. Remote Sensing, 12, 1579, doi:10.3390/rs12101579
Yuan, LL, SG Jin, and A Calabia (2019), Distinct thermospheric mass density variations following the September 2017 geomagnetic storm from GRACE and SWARM precise orbits, J. Atmos. Solar Terrest. Phys., 184, 30-36, doi: 10.1016/j.jastp.2019.01.007
Zhang, Y, LJ Paxton, G Lu, and S Yee (2019), Impact of nitric oxide, solar EUV and particle precipitation on thermospheric density decrease J. Atmos. Solar Terrest. Phys, 182, 147-154. doi: 10.1016/j.jastp.2018.11.016
Zhu, Q, Deng, Y, Richmond, A, McGranaghan, RM, and Maute, A (2019), Impacts of multiscale field-aligned currents (FACs) on the ionosphere-thermosphere: GITM simulation, Journal of Geophysical Research: Space Physics, 124, 3532 3542, doi:10.1029/2018JA026082
Zhu, Q, Y Deng, A Richmond, and A Maute (2018), Small-scale and mesoscale variabilities in the electricfield and particle precipitation and their impacts on Joule heating. Journal of Geophysical Research: Space Physics, 123, 9862-9872, doi:10.1029/2018JA025771


Calabia, A, and SG Jin, Upper Atmospheric Characterization through Neutral and Electron Density Observables, oral presentation at IUGG 2019 General Assembly, Montreal, Canada, 8 to 18 July 2019.
Calabia, A, and SG Jin, Thermospheric mass density perturbations due to Space Weather from LEO GPS POD and accelerometer, oral presentation at 2019 Workshop on Smart Navigation and Applications and Annual Meeting of Jiangsu Engineering Center for Navigation, Nanjing, China, 11-13, January 2019.
Shah, M, Low latitude ionospheric variations associated with geomagnetic storm in Pakistan from GNSS TEC, International Nithiagali Summer School, Islamabad, June 11-13, 2019.
Jin, SG, and LL Yuan, Thermospheric variations from GNSS and accelerometer observations on GRACE and Swarm, The 4th COSPAR Symposium on Small Satellites for Sustainable Science and Development, Herzliya, Israel, 4-8 November, 2019.
Yasyukevich, Yu, et al. Ionosphere modeling and monitoring using GPS and GLONASS techniques. Invited talk at the 10th China satellite navigation conference. Beijin, China. May 22-25, 2019.

Website & Forum

Data & Software Products

Andres Calabia, & Shuanggen Jin. (2019, May 29). Supporting Information for “Solar-cycle, seasonal, and asymmetric dependencies of thermospheric mass density disturbances due to magnetospheric forcing”. Zenodo.
Calabia, Andres, & Jin, Shuanggen. (2019, December 5). Supporting Information for “New modes and mechanisms of long-term ionospheric TEC variations from Global Ionosphere Maps”. Zenodo.
SIMuRG: System for Ionosphere Monitoring and Research from GNSS.

(last update 09.2020)