Qian Wu

Penetrating electric field with/without disturbed electric fields During the 7-8 July 2022 geomagnetic storm simulated by MAGE and observed by ICON MIGHTI

whawkins — Wed, 09 Apr 2025 21:17:49 +0000

Penetrating electric field with/without disturbed electric fields During the 7-8 July 2022 geomagnetic storm simulated by MAGE and observed by ICON MIGHTI whawkins Wed, 04/09/2025 - 15:17

Author:

whawkins

Apr 9, 2025

7 July, MAGE simulation and ICON observation of zonal thermospheric winds and ion drifts. ICON MIGHTI observed zonal wind and MAGE simulations along the MIGHTI sampling points (right) are plotted. Data from each orbit are plotted according to the longitude. The starting time for each orbit is provided. The midnight is marked by blue triangles. MIGHTI data gaps are due to SAA (South Atlantic Anomaly) or day-night transitions (see Englert et al., 2023). The IMF Bz southward turning occurred after 12 UT, which is highlighted by a dashed oval. The nightside zonal wind start to see reaction in the next orbit. Not much change is seen on the dayside. The ExB meridional ion drifts (vertical upward at the magnetic equator) for each orbit are plotted on the right.

JGR Space Physics: Using a numerical model where the coupled physical processes of the magnetosphere, ionosphere, and thermosphere are represented, we simulated the nighttime ionospheric disturbances caused by electric fields that enter this system from the magnetosphere and electric fields generated internally by changes in the thermospheric winds. The former is quick to reach the low latitudes, and the latter is delayed by the slower response of the neutral winds. The coupled model and NASA satellite observation showed good agreement. The results show good capability and lend themselves to the future effort to forecasting space weather at low latitudes.

HIWIND Balloon and Antarctica Jang Bogo FPI High Latitude Conjugate Thermospheric Wind Observations and Simulations

whawkins — Fri, 21 Jun 2024 18:59:58 +0000

HIWIND Balloon and Antarctica Jang Bogo FPI High Latitude Conjugate Thermospheric Wind Observations and Simulations whawkins Fri, 06/21/2024 - 12:59

Author:

whawkins

Jun 21, 2024

JGR Space Physics: Using balloon instrument in the northern hemisphere and ground based instrument in the southern hemisphere, we study the conjugacy of the thermospheric winds of high latitudes. We found that the more summer hemispheric heating alters the thermospheric winds and resulted in a double-hump feature on the dayside meridional winds. We also used model with cusp heating to simulate the winds and were able to reproduce the double-hump feature.

Thermospheric wind observations from HIWIND (northern summer) and JBS (southern winter) along with the TIEGCM simulations at the respective locations. The JBS data were shifted by 7 hours so that the local time of the JBS is approximately equal to that of HIWIND. The meridional winds from JBS were reversed so that the poleward meridional winds from JBS is positive for easy comparison with HIWIND data. The prominent double hump feature in northern hemisphere meridional winds (HIWIND, upper penal) is a result of the high energy input in the summer hemisphere.
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MAGE Model Simulation of the Pre-reversal Enhancement and Comparison with ICON and Jicamarca ISR Observations

whawkins — Fri, 21 Jun 2024 18:52:03 +0000

MAGE Model Simulation of the Pre-reversal Enhancement and Comparison with ICON and Jicamarca ISR Observations whawkins Fri, 06/21/2024 - 12:52

Author:

whawkins

Jun 21, 2024

JGR Space Physics: Using the latest coupled geospace model MAGE (Multiscale Atmosphere-Geospace Environment) and observations from Jicamarca ISR and ICON IVM instrument, we examine the pre-reversal enhancement during geomagnetic quiet time period. The MAGE shows comparable PRE to both the Jicamarca ISR and ICON observations. There appears to be a discrepancy between the Jicamarca ISR and ICON IVM with the later showed PRE about two times larger (~ 40 m/s). This is the first time that MAGE is used to simulate the PRE. The results show that the MAGE can simulate the PRE well and are mostly consistent with observations.

MAGE simulations of the equatorial vertical ion drifts (black vectors along the magnetic equator) at 23:49 UT. The MAGE simulated ExB meridional ion drift (IVM definition) sampled along the ICON satellite track (black line above the satellite track shown as the dashed line) and the IVM observed ExB meridional drift (lime or magenta vector) from 23:15 to 23:55 UT. The magenta vectors are values near 2349 UT. The PRE is visible in the simulated equatorial vertical ion drift and in both the MAGE simulated and ICON observed ExB meridional ion drifts along the satellite tracks . The background shows the nmf2 from the MAGE simulation.

Penetrating Electric Field Simulated by the MAGE and Comparison with ICON Observation

whawkins — Wed, 21 Sep 2022 17:55:07 +0000

Penetrating Electric Field Simulated by the MAGE and Comparison with ICON Observation whawkins Wed, 09/21/2022 - 11:55

Author:

whawkins

Sep 21, 2022

JGR Space Physics: Qian Wu, Wenbin Wang, Dong Lin, Chaosong Huang, and Yongliang Zhang use the newly developed, Multiscale Atmosphere-Geospace Environment (MAGE) model to simulate the penetrating electric field in the equatorial region under different interplanetary magnetic field (IMF) BZ conditions during September 2020. Two intervals were selected for detailed analysis and the latter one was compared with the vertical ion drift data from the NASA Ionospheric Connection Explorer (ICON) satellite. The MAGE simulations show that in southward IMF (S-IMF) cases, the dawn-dusk electric potential drop at the equator is about 12% of the cross polar cap potential difference. Based on the MAGE simulation, the dawn-dusk potential drop at the equator varies nearly instantaneously on the order of a few minutes with the changes in the IMF BZ or interplanetary electric field, which in turn alters the vertical ion drift. The daytime changes of the equatorial vertical ion drift in response to the penetrating electric field related to the IMF BZ are only half of that during the nighttime. ICON data, though not inconsistent with the simulation, were not able to verify the occurrence of penetrating electric field because of its unfavorable location at the time. The MAGE simulation shows a pre-reversal enhancement (PRE) during southward IMF cases, but the PRE was absent in the ICON IVM observations. Further observations and modeling are needed to resolve this discrepancy.

Nightside vertical ion drift at the magnetic equator (black arrows downward drift shown as pointing southward in the figure) of September 24, 05-06 UT (A). Background is the nmf2 from the MAGE. Dusk is on the left. EIAs are clearly seen on the duskside. PRE is present in the first case. The vertical ion drift varies with IMF Bz component and equatorial electric field. During S-IMF cases, the vertical ion drifts are mostly downward. The scale vector is for 20 m/s.

HIWIND Prepares for a New Zealand Flight in 2022

kolinski — Thu, 18 Nov 2021 21:06:13 +0000

HIWIND Prepares for a New Zealand Flight in 2022 kolinski Thu, 11/18/2021 - 14:06

A comparison of Fabry-Perot interferometer and meteor radar wind measurements near the polar mesopause region

kolinski — Mon, 15 Nov 2021 23:01:33 +0000

A comparison of Fabry-Perot interferometer and meteor radar wind measurements near the polar mesopause region kolinski Mon, 11/15/2021 - 16:01

Publication Name: JGR Space Physics; First HAO Author: Qian Wu; Authors as listed in article: Changsup Lee, Geonhwa Jee, Hosik Kam, Qian Wu, Young-Bae Ham, Yong Ha Kim, and Jeong-Han Kim

Author:

kolinski

Nov 15, 2021

The neutral winds in the Mesosphere and Lower Thermosphere (MLT) region have been observed at King Sejong Station, Antarctica using a meteor radar and a Fabry-Perot interferometer (FPI) simultaneously. These two independent MLT wind measurements are compared to each other to identify the characteristics of FPI measurement. Instead of using a fixed emission height for FPI winds, for the first time, we consider the temporal variations of airglow emission layer in association with corresponding meteor height distributions for more accurate comparison between the FPI and meteor radar winds.

Scatterplots of hourly mean zonal and meridional wind components at OI layer (a, b), OH layer (c, d) measured by the FPI and MR in 2017 and 2019, respectively. The 2-year averaged correlation coefficients (ρ), linear slopes and intercepts are presented on each scatterplot. The colored solid line denotes the regression line of FPI against MR winds. The black solid line shows the line of equality.

The temporal variations of the airglow emission layers are examined from the inverse relationship between the height integrated emission rate and the peak emission height derived from the TIMED/SABER observations. It is found that FPI winds are consistently smaller than meteor radar winds and the discrepancy becomes larger for OI emission at higher altitude, which may be related to large wind shear in the MLT region and variabilities of the emission layers. Finally, we found that the FPI can provide reliable height-averaged winds in the MLT region where existing a strong wind shear from this simultaneous MR wind measurements.

COSMIC Observation of Stratospheric Gravity Wave and Ionospheric Scintillation Correlation

kolinski — Mon, 15 Nov 2021 21:09:17 +0000

COSMIC Observation of Stratospheric Gravity Wave and Ionospheric Scintillation Correlation kolinski Mon, 11/15/2021 - 14:09

Publication Name: Space Weather; First HAO Author's Name: Qian Wu; Authors names as they are listed in article: Qian Wu, Min-Yang Chou, W. Schreiner, J. Braun, N. Pedatella, Iurii Cherniak

Author:

kolinski

Nov 15, 2021

A correlation study is performed to investigate possible connections between the stratospheric gravity waves and the ionospheric plasma bubble induced GPS signal scintillations. Using the COSMIC 1 neutral temperature data (10–30 km), we extract gravity wave amplitudes with vertical wavelengths from 2.5 to 10 km within the latitudinal range from 37.5S to 37.5N.

High S4 occurrence (> 0.2) longitudinal and annual variations from 2010 to 2013. The data are binned in 1-day and 10-degree longitudinal grids. The data are selected from 25S to 25N latitudinal and 240 to 450 km altitudinal ranges. The local time range is from 15 to 21 LT.

We then calculated the occurrence of high GPS L1 amplitude scintillation (S4 > 0.2) in the equatorial region (25S and 25N). The high S4 values showed consistent higher correlations with gravity waves at the equator than those away from the equator for all vertical wavelengths between 2010 and 2013. While the peak correlation is only ~ 0.2, the consistency over different wavelengths and years suggests a possible link, which could be through seeding of plasma bubbles and/or modulation of the neutral wind dynamo by gravity waves. We see the need for further study based on statistics of simultaneous observations of gravity waves, ionospheric scintillations, and other ionospheric and thermospheric parameters, which can lead to a better understanding of the plasma bubble formation mechanism.

Characteristics of small-scale gravity waves in the Arctic winter mesosphere

kolinski — Mon, 15 Nov 2021 21:05:14 +0000

Characteristics of small-scale gravity waves in the Arctic winter mesosphere kolinski Mon, 11/15/2021 - 14:05

Publication: JGR Space Physics; HAO Author: Qian Wu; Authors as listed in article: Jing Li, Tao Li, Qian Wu, Yihuan Tang, Zhaopeng Wu, Jun Cui

Author:

kolinski

Nov 15, 2021

Observational datasets in the polar middle atmosphere are extremely valuable for understanding the polar dynamics and coupling between lower and middle atmosphere. Using the long-term datasets observed with an OH all-sky imager, a Fabry-Perot Interferometer at Resolute Bay observatory, Canada (74.7°N, 94.9°W), and Microwave Limb Sounder and reanalysis data, we study the characteristics of small-scale gravity waves (GWs) with the horizontal wavelength less than 20 km in the Arctic winter mesosphere during 2014-2016. Most of the GWs propagate nearly against the mesospheric and stratospheric winds, consistent with the wind filtering theory. A small amount (7 of 36 cases) of small-scale GWs in large regions (area >1/2 of the whole image) propagate nearly westward with smaller phase speeds, larger horizontal wavelengths and longer periods than those in limited regions.

Histogram of small-scale GWs’ parameters observed by All-sky OH airglow imager at Resolute Bay Observatory, including (a) propagating direction, (b) phase speed, (c) horizontal wavelength, (d) period, (e) occurrence time, (f) lifetime.

We also find that multiple GWs with different propagating directions occurred simultaneously only when the wind speed is much smaller than the GW phase speed. The observed small-scale GWs may be excited in the mesopause region, such as secondary wave generated by primary wave breaking, or a result of baroclinic instability processed in the stratosphere, and the interaction of planetary waves with the background winds. In addition, almost all of the small-scale GWs occurred in 2015/2016 anomalous winter, when both the strong El Nino-Southern Oscillation (ENSO) and anomalous Quasi-biennial Oscillation (QBO) happened. Further studies are needed to explore the mechanism of GW excitation and propagation.

Qian Wu

Penetrating electric field with/without disturbed electric fields During the 7-8 July 2022 geomagnetic storm simulated by MAGE and observed by ICON MIGHTI

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Penetrating Electric Field Simulated by the MAGE and Comparison with ICON Observation

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HIWIND Prepares for a New Zealand Flight in 2022

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A comparison of Fabry-Perot interferometer and meteor radar wind measurements near the polar mesopause region

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COSMIC Observation of Stratospheric Gravity Wave and Ionospheric Scintillation Correlation

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Characteristics of small-scale gravity waves in the Arctic winter mesosphere

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