Thermospheric Mass Density Disturbances Due to Magnetospheric Forcing From 2014–2020 CASSIOPE Precise Orbits

Abstract

Long‐term thermospheric mass density disturbances due to magnetospheric forcing are not clear due to a lack of measurement data and imprecise models. In this study, the Global Navigation Satellite System (GNSS) precise orbits of CAScade SmallSat and IOnospheric Polar Explorer (CASSIOPE) are used to infer high‐resolution thermospheric mass densities between the years 2014 and 2020. The CASSIOPE densities are comprehensively validated at altitudes from 325 to 425 km at intervals of 25 km with the High Accuracy Satellite Drag Model (HASDM) density database, and further compared with the Naval Research Laboratory Mass Spectrometer and Incoherent Scatter Radar Exosphere/2000 (NRLMSISE‐00) and the Jacchia‐Bowman/2008 (JB2008) empirical models. The CASSIOPE densities are very similar to the HASDM and JB2008 densities, while the NRLMSISE‐00 largely overestimates (∼150%) during low solar‐flux conditions. For density values above ∼10−12 kg/m3, the correlation of CASSIOPE with HASDM is ∼5% better than the models, and the standard deviation is within 10% of the background density. For density values below ∼10−12 kg/m3, systematic errors have shown to reduce the precision of the CASSIOPE densities. By setting geomagnetic contributions to zero in the models, the density disturbances due to magnetospheric forcing are isolated from the CASSIOPE time‐series, allowing investigation into the correlations and time‐delay responses to the models and to the merging electric field (Em). A new linear dependence of the time delay to the Em was found and then parameterized in this study. Time delays occurred at the 4–7 h range during geomagnetic storms, and at 9–11 h during quiet conditions; neither had significant dependence on altitude. The results represent the validation of the first high‐resolution thermospheric mass density estimates inferred from commercial‐off‐the‐shelf GNSS receivers.

The current state and future directions of modeling thermosphere density enhancements during extreme magnetic storms

“…Typically, 75 calibration satellites are used to fit and correct the JB2008 density and the greater the number of calibration satellites, the higher the accuracy. Because HASDM is able to mitigate uncertainty in atmospheric effects, by resolving the differences between calibration satellites and the core JB2008 model at each epoch (time step), real-time nowcasting specification of the LEO drag environment has improved significantly (e.g., Storz et al, 2005;Bowman et al, 2008;Licata et al, 2021b;Calabia and Jin, 2021).…”

Koudougou (Burkina Faso, Africa), GPS-TEC Response to Recurrent Geomagnetic Storms during Solar Cycle 24 Declining Phase

“…During storms, solar wind/magnetosphere coupling leads to increased Joule heating. This results perturbations in the composition, temperature, density, and winds of the upper atmosphere [27][28][29] that influence aerospace systems and associated human technologies. Examples of activities directly impacted are radio wave propagation, sending signals between satellites and Earth, control of communication and navigation systems, etc.…”

Uncertainty quantification techniques for data-driven space weather modeling: thermospheric density application

“…Integrating the density datasets of Gravity Recovery and Climate Experiment (GRACE) 33 , Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) 34 , and Swarm 35 would provide a thorough altitude coverage of approximately 220–550 km and span from 2001 to present day. The Enhanced Polar Outflow Probe (e-POP) 36 is a payload on Cascade, Smallsat and Ionospheric Polar Explorer (CASSIOPE) and its density estimates can be obtained through the processing of its Global Navigation Satellite System (GNSS) receivers 37 , 38 . However, there is still much active research related to the proper combination of different satellite density datasets 39 – 41 .…”