ALBERT

Description: Providing accurate measurement of the magnetic field intensity and its vector components is one of the primary objectives of the China Seismo‐Electromagnetic Satellite (CSES). The high precision magnetometer (HPM) payload assembled on CSES is designed to achieve this goal. In this study, the data format, naming convention, and content of the CSES HPM Level 2 scientific data products are introduced, as a reference for users who are interested in this data set. In particular, flags for potential magnetic field disturbances from the platform and payloads are discussed. Possible scientific applications are also outlined. A preliminary validation of the data is conducted through comparison with magnetic data from the ESA’s Swarm constellation, and the result demonstrates that the HPM data of CSES are of good quality. Taking the intense geomagnetic storm that occurred on August 25–26, 2018 as an example, the magnetic field variations and the expansion of the field‐aligned currents (FACs) during this storm are discussed. We finally show that the CSES HPM data can be used to derive a satellite‐derived index equivalent to the Dst index, which agrees well to the index during this event. Our analysis thus suggests a high scientific potential of the HPM data.

Description: In December 2019, the International Association of Geomagnetism and Aeronomy (IAGA) Division V Working Group (V-MOD) adopted the thirteenth generation of the International Geomagnetic Reference Field (IGRF). This IGRF updates the previous generation with a definitive main field model for epoch 2015.0, a main field model for epoch 2020.0, and a predictive linear secular variation for 2020.0 to 2025.0. This letter provides the equations defining the IGRF, the spherical harmonic coefficients for this thirteenth generation model, maps of magnetic declination, inclination and total field intensity for the epoch 2020.0, and maps of their predicted rate of change for the 2020.0 to 2025.0 time period.

Description: Strong natural hazards events are assumed to be significant sites to investigate the lithosphere-atmosphere-ionosphere coupling (LAIC), showing possibly a multitude of processes up to high altitudes. Until now there is no clear consensus on how specific mechanisms affect the different layers and important questions persist. In this study we analyse European earthquake events with magnitudes M ≥ 5 based on the USGS catalogue, a second focal point is a particular class of volcanic eruptions selected from Mt. Etna (Sicily, Italy) activity periods. We examine electric field variations in the earth-ionosphere waveguide along radio paths between narrowband VLF/LF transmitters and ground-based receiver facilities (INFREP network). Those observations are combined with in-situ satellite magnetic field measurements from the missions Swarm and CSES-1 at LEO altitudes. For both investigations spatio-temporal proximity to the event sites is necessary. The selected bundling of the two field parameters enables the steady VLF/LF electric-field measurements from the lithosphere up to the ionospheric D/E-region and the satellite measurements assess parts at the end of the propagation channel in the ionospheric F-region at about 500 km altitude.Results for volcanic eruptions show a decrease in the VLF/LF electric fields of up to 10 dB with fluctuations in the frequency range of atmospheric gravity waves (AGWs). Earthquakes exhibit larger VLF/LF amplitude values after the event (night-time amplitude method). We find no clear signatures in the ionospheric satellite magnetic field measurements, but future missions like CSES-2 double the revisiting frequency above natural hazards prone areas and will facilitate further in-detail investigations.