TY - JOUR
T1 - Ionospheric responses to the 21 August 2017 solar eclipse by using data assimilation approach
AU - Chen, Chia-Hung
AU - Lin, Charles
AU - Matsuo, Tomoko
N1 - Funding Information:
The source code for the assimilation system and simulation model used in this study, the DART and TIEGCM, are available at https://www.image.ucar.edu/DAReS/DART/ and https://www.hao.ucar.edu/modeling/tgcm/ , respectively. The authors are grateful for the NCAR High Altitude Observatory and Data Assimilation Research Section for their support of TIEGCM and DART software. This paper is supported by Ministry of Science and Technology (MOST) and National Space Organization (NSPO) of Taiwan to National Cheng Kung University under MOST-107-2119-M-006-023 and NSPO-S-108002. The observations data from ground-based GPS receivers are available at IGS (https://garner.ucsd.edu/).
Publisher Copyright:
© 2019, The Author(s).
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Using the physics-based thermosphere-ionosphere model (NCAR-TIEGCM) with an ensemble Kalman filter, this study reports the first data assimilative analysis of the ionosphere responses to the solar eclipse on 21 August 2017. The system, using a 2-min assimilation cycle of data from ground-based GNSS observations, show dynamic variations of the equatorial ionization anomaly (EIA) due to the electrodynamic effects of the solar eclipse. Two major ionospheric responses are captured: (1) an early appearance of EIA at the westward boundary of moon shadow and (2) an enhanced EIA at lower latitudes and suppressed EIA at the higher latitudes. These eclipse-induced conjugate EIA variations are produced by an eastward electric field perturbation around the magnetic equator and a westward electric field perturbation at the higher latitudes. [Figure not available: see fulltext.].
AB - Using the physics-based thermosphere-ionosphere model (NCAR-TIEGCM) with an ensemble Kalman filter, this study reports the first data assimilative analysis of the ionosphere responses to the solar eclipse on 21 August 2017. The system, using a 2-min assimilation cycle of data from ground-based GNSS observations, show dynamic variations of the equatorial ionization anomaly (EIA) due to the electrodynamic effects of the solar eclipse. Two major ionospheric responses are captured: (1) an early appearance of EIA at the westward boundary of moon shadow and (2) an enhanced EIA at lower latitudes and suppressed EIA at the higher latitudes. These eclipse-induced conjugate EIA variations are produced by an eastward electric field perturbation around the magnetic equator and a westward electric field perturbation at the higher latitudes. [Figure not available: see fulltext.].
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U2 - 10.1186/s40645-019-0263-4
DO - 10.1186/s40645-019-0263-4
M3 - Article
AN - SCOPUS:85061040832
SN - 2197-4284
VL - 6
JO - Progress in Earth and Planetary Science
JF - Progress in Earth and Planetary Science
IS - 1
M1 - 13
ER -