Jing Liu

NASA Features Research by HAO Scientist Xuguang Cai

kolinski — Thu, 18 Nov 2021 20:58:13 +0000

NASA Features Research by HAO Scientist Xuguang Cai kolinski Thu, 11/18/2021 - 13:58

HIWIND Observation of Summer Season Polar Cap Thermospheric Winds

kolinski — Thu, 18 Nov 2021 19:10:39 +0000

HIWIND Observation of Summer Season Polar Cap Thermospheric Winds kolinski Thu, 11/18/2021 - 12:10

Publication Name: JGR Space Physics; First HAO Author's Name: Qian Wu

Author:

kolinski

Nov 18, 2021

HIWIND (High altitude Interferometer WIND experiment) is a balloon borne Fabry Perot interferometer (FPI) for daytime thermospheric wind observations. In this paper, we examine the summer polar cap thermospheric winds observed by HIWIND with the RISR-C (Resolute Incoherent Scatter Radar-Canada) observed ion drifts and electron densities.

HIWIND thermospheric winds (magenta points) and TIEGCM NSEP (green 435 solid-lines) and MSEP (green dashed-lines) simulated winds are plotted on the left. 436 RISR-C ion drift observations (yellow line) and TIEGCM NSEP (blue solid-lines) and 437 MSEP (blue dashed-lines) simulated ion drifts are on the right. Local midnight is close 438 to 6 UT and noon at 18 UT. The key point of the paper is that the TIEGCM simulation greatly overestimate thermospheric winds in the polar cap.

We also perform NCAR TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation Model) simulations to compare with the HIWIND and RISR-C observations. The standard TIEGCM underestimates the high-latitude electron density and overestimates the thermospheric winds. The discrepancies between modeled and observed meridional winds are large near midnight and noon. After increasing the energy flux in the polar cap drizzle, the simulated electron density is comparable with the RISR-C observations. However, large discrepancies with the HIWIND observed thermospheric winds persist. The cause of the model versus observation discrepancy in winds is probably due to the processes outside the polar cap.

Formation of Double Tongues of Ionization During the 17 March 2013 Geomagnetic Storm

kolinski — Tue, 16 Nov 2021 22:25:03 +0000

Formation of Double Tongues of Ionization During the 17 March 2013 Geomagnetic Storm kolinski Tue, 11/16/2021 - 15:25

Publication Name: Journal of Geophysical Research: Space Physics; First HAO Author: Wenbin Wang; Authors: Dang, T., Lei, J., Wang, W., Wang, B., Zhang, B., Liu, J., et al

Author:

kolinski

Nov 16, 2021

During geomagnetic disturbances, enhanced high‐latitude convection transports ionospheric F2‐region plasma from the dayside midlatitude region into the polar cap, leading to structures such as tongues of ionization (TOIs) and patches. In this study, we investigate the dynamic evolution of TOIs during the 17 March 2013 storm using a high‐resolution coupled thermosphere‐ionosphere‐electrodynamics model and Defense Meteorological Satellite Program (DMSP) satellite observations.

Polar maps of the simulated electron density at pressure level 2 (~300 km) in the Northern Hemisphere as a function of geographic latitude and local time on 17 March 2013.

Both model and observations show the occurrence of two TOIs simultaneously. One originates in the morning convection cell and the other one in the evening cell. DMSP observations also show similar signatures of two density peaks inside the polar cap. Further diagnostic analysis and control simulations show that the morning TOI is associated with auroral precipitation and is transported into the polar cap region by the convection electric field. This study reveals that the plasma transport in both the afternoon and morning sectors play critical roles in the dynamic evolution of polar ionospheric structures.

Link to paper: Formation of Double Tongues of Ionization During the 17 March 2013 Geomagnetic Storm

Observation of Postsunset OI 135.6 nm radiance Enhancement in South America by the Global-scale Observation of Limb and Disk (GOLD) Mission

kolinski — Tue, 16 Nov 2021 21:43:25 +0000

Observation of Postsunset OI 135.6 nm radiance Enhancement in South America by the Global-scale Observation of Limb and Disk (GOLD) Mission kolinski Tue, 11/16/2021 - 14:43

Publication: Journal of Geophysical Research—Space Physics; Authors: Xuguang Cai, Alan G. Burns, Wenbin Wang, Liying Qian, Jing Liu, Stanley C. Solomon, Richard W. Eastes, Robert E. Daniell

Author:

kolinski

Nov 16, 2021

The Global-scale Observation of Limb and Disk (GOLD) mission, for the first time, provides synoptic two-dimensional (2D) maps of OI 135.6 nm observations. These maps describe the unambiguous and dynamic evolution of nighttime ionospheric F2-peak electron densities (NmF2) as the 135.6 nm airglow emission radiance correlates well with NmF2 at night. On November 19, 2018, the 135.6 nm radiance measured by GOLD, NmF2 measured by a digisonde, and GPS total electron content (TEC) measurements at Cachoeira Paulista (CP) all showed a postsunset enhancement, with an increase near 22:30 universal time.

The latitude-longitude distribution of the OI 135.6 nm radiance measured by GOLD Channel B from 22:25 to 23:55 UT (22:25, 22:55, 23:10, 23:25, 23:40 and 23:55) on Nov 19, 2018. The white cross in each subplot marked the location of CP (22.7°S, 45°W), and the black point is the location of EIA southern crest peak at 45°W. The red line marked the coast line of South America continent. The white area on each subplot stand for the area that is not scanned by GOLD.

The 135.6 nm radiance map showed that this enhancement was due to the southward movement of the southern equatorial ionization anomaly (EIA) crest. Therefore, the GOLD observation showed the linkage between postsunset enhancement of NmF2 and EIA movement. Furthermore, unlike the southward movement of the southern crest, the corresponding EIA northern crest, however, did not show northward motion. This is the first time that the EIA hemispheric asymmetry, which included both different densities and movement of two crests in a short time period (less than 2-hours), was captured. The cause of this asymmetric movement of the two crests is not clear and requires further investigation.

Geospace response to an extreme solar flare

kolinski — Mon, 15 Nov 2021 21:58:00 +0000

Geospace response to an extreme solar flare kolinski Mon, 11/15/2021 - 14:58

Publication Name: AGU Advances; HAO Author: Jing Liu; Authors names as listed: Jing Liu, Wenbin Wang, Liying Qian, William Lotko, Alan G. Burns, Kevin Pham, Gang Lu, Stanley C. Solomon, et al.

Author:

kolinski

Nov 15, 2021

Solar flares—a sudden eruption of electromagnetic radiation at the Sun—are known to have significant impacts on Earth’s upper atmosphere and ionosphere, but their collective effects on geospace as an integrated system have never been examined. We use a newly developed whole geospace model, combined with key observational data, to study the effects of the 6 September 2017 X9.3 flare on the geospace system.

Solar flare effects on magnetospheric convection and ionospheric potential. Comparison of 50-minute averages (12:02-12:51 UT) from LTR simulations of magnetospheric and ionospheric states on September 6, 2017 with and without solar flare effects. Bottom row: LTR-simulated magnetospheric convection velocity in equatorial plane (ZGSM = 0) with (A) and without (B) solar flare effects and their difference (C). Arrows indicate direction and magnitude (also in color) of the convection velocity projected onto the plane. Top row: High-latitude electric potential, essentially convection streamlines in the ionosphere with (D) and without (E) solar flare effects and their difference (F). The minimum and maximum potentials are labeled below panels (D-F).

The analysis shows that the solar wind-magnetosphere interaction, magnetotail, field-aligned current distribution, auroral precipitation and high-latitude ionospheric convection respond to atmospheric absorption of solar flare radiation. This study, for the first time, demonstrates that a rapid and large increase in the iono-spheric E-region photoionization due to a solar transient event globally modifies the electrodynamic cou-pling of the geospace system.

Jing Liu

NASA Features Research by HAO Scientist Xuguang Cai

Recent News

HIWIND Observation of Summer Season Polar Cap Thermospheric Winds

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Formation of Double Tongues of Ionization During the 17 March 2013 Geomagnetic Storm

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Observation of Postsunset OI 135.6 nm radiance Enhancement in South America by the Global-scale Observation of Limb and Disk (GOLD) Mission

Recent News

Geospace response to an extreme solar flare

Recent News