Bibliography

Observations and Modeling of Atomic/Molecular Composition in the Thermosphere

Solomon, Stanley; Eastes, Richard; McClintock, William; Paxton, Larry; Zhang, Yongliang;

Published by: Published on:

YEAR: 2018 DOI:

Reconstruction the Ionospheric Responses to the October-November 2003 Halloween Super Storm: A Data Assimilation Approach

Chang, Yu-Shan; Chen, Chia-Hung; Lin, Charles; Chu, Hung-Hsuan; Matsuo, Tomoko;

Published by: Published on:

YEAR: 2018 DOI:

Vertical Thermospheric Density Profiles From EUV Solar Occultations Made by PROBA2 LYRA for Solar Cycle 24

A new data set of summed neutral N₂ and O number density profiles, spanning altitudes between 150 and 400\ km, and observed during Northern Winter from 2010 to 2016 is presented. The neutral density profiles are derived from solar occultation measurements made by the 0.1\textendash20\ nm Zr channel on the Large Yield Radiometer (LYRA) instrument on board Project for Onboard Autonomy 2 (PROBA2). The climatology derived from the vertical profiles is consistent with that predicted by the NRLMSISE-00 model, and the systematic error and random uncertainty of the measurements are less than 13\% and 6\%, respectively. The density profiles are used to characterize the response of thermospheric density to solar EUV irradiance variability. Peak correlation coefficients between neutral density and EUV irradiance occur near 300\ km at the dusk terminator and 220\ km at the dawn terminator. Density variability is higher at dawn than it is at dusk, and temperature variability increases with increasing altitude at both terminators.

Thiemann, E.; Dominique, M.; Pilinski, M.; Eparvier, F.;

Published by: Space Weather Published on: 12/2017

YEAR: 2017 DOI: 10.1002/2017SW001719

The Far Ultra-Violet Imager on the Icon Mission

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N₂ ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to compute the nighttime ionospheric altitude distribution. ICON Far UltraViolet (FUV) imager is a Czerny\textendashTurner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to overcome the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft.

Mende, S.; Frey, H.; Rider, K.; Chou, C.; Harris, S.; Siegmund, O.; England, S.; Wilkins, C.; Craig, W.; Immel, T.; Turin, P.; Darling, N.; Loicq, J.; Blain, P.; Syrstad, E.; Thompson, B.; Burt, R.; Champagne, J.; Sevilla, P.; Ellis, S.;

Published by: Space Science Reviews Published on: 10/2017

YEAR: 2017 DOI: 10.1007/s11214-017-0386-0

The Global-Scale Observations of the Limb and Disk (GOLD) Mission

The Earth\textquoterights thermosphere and ionosphere constitute a dynamic system that varies daily in response to energy inputs from above and from below. This system can exhibit a significant response within an hour to changes in those inputs, as plasma and fluid processes compete to control its temperature, composition, and structure. Within this system, short wavelength solar radiation and charged particles from the magnetosphere deposit energy, and waves propagating from the lower atmosphere dissipate. Understanding the global-scale response of the thermosphere-ionosphere (T-I) system to these drivers is essential to advancing our physical understanding of coupling between the space environment and the Earth\textquoterights atmosphere. Previous missions have successfully determined how the \textquotedblleftclimate\textquotedblright of the T-I system responds. The Global-scale Observations of the Limb and Disk (GOLD) mission will determine how the \textquotedblleftweather\textquotedblright of the T-I responds, taking the next step in understanding the coupling between the space environment and the Earth\textquoterights atmosphere. Operating in geostationary orbit, the GOLD imaging spectrograph will measure the Earth\textquoterights emissions from 132 to 162 nm. These measurements will be used image two critical variables\textemdashthermospheric temperature and composition, near 160 km\textemdashon the dayside disk at half-hour time scales. At night they will be used to image the evolution of the low latitude ionosphere in the same regions that were observed earlier during the day. Due to the geostationary orbit being used the mission observes the same hemisphere repeatedly, allowing the unambiguous separation of spatial and temporal variability over the Americas.

Eastes, R.; McClintock, W.; Burns, A.; Anderson, D.; Andersson, L.; Codrescu, M.; Correira, J.; Daniell, R.; England, S.; Evans, J.; Harvey, J.; Krywonos, A.; Lumpe, J.; Richmond, A.; Rusch, D.; Siegmund, O.; Solomon, S.; Strickland, D.; Woods, T.; Aksnes, A.; Budzien, S.; Dymond, K.; Eparvier, F.; Martinis, C.; Oberheide, J.;

Published by: Space Science Reviews Published on: 10/2017

YEAR: 2017 DOI: 10.1007/s11214-017-0392-2

Model simulations of ion and electron density profiles in ionospheric E and F regions

We develop a time‐dependent theoretical numerical model to simulate the density profiles of the ions (ie, O + ( 2 P), O + ( 2 D), N 2 + , O + ( 4 S), N + , O 2 + , and NO + ) and free

Lin, YC; Chu, YH;

Published by: Journal of Geophysical Research: Space Physics Published on:

YEAR: 2017 DOI: 10.1002/2016JA022855

Predictable and unpredictable ionospheric disturbances during St. Patrick s Day magnetic storms of 2013 and 2015 and on 8—9 March 2008

We present a comparative analysis of first principles Global Self‐consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) in prediction of ionospheric

Dmitriev, AV; Suvorova, AV; Klimenko, MV; Klimenko, VV; Ratovsky, KG; Rakhmatulin, RA; Parkhomov, VA;

Published by: Journal of Geophysical Research: Space Physics Published on:

YEAR: 2017 DOI: 10.1002/2016JA023260

Data-Driven Inference and Investigation of Thermosphere Dynamics and Variations

Mehta, Piyush; Linares, Richard; Sutton, Eric;

Published by: order Published on:

YEAR: 2017 DOI:

Studying the ionosphere response to severe geomagnetic storm in March 2015 according to Eurasian ionosonde chain

Shpynev, BG; Zolotukhina, NA; Polekh, NM; Chernigovskaya, MA; Ratovsky, KG; Belinskaya, Yu; Stepanov, AE; Bychkov, VV; Grigorieva, SA; Panchenko, VA; , others;

Published by: Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa Published on:

YEAR: 2017 DOI:

Impacts of SABER CO ₂ -based eddy diffusion coefficients in the lower thermosphere on the ionosphere/thermosphere

This work estimates global-mean K_zz using Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics monthly global-mean CO₂ profiles and a one-dimensional transport model. It is then specified as a lower boundary into the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM). Results first show that global-mean CO₂ in the mesosphere and lower thermosphere region has annual and semiannual oscillations (AO and SAO) with maxima during solstice seasons along with a primary maximum in boreal summer. Our calculated AO and SAO in global-mean CO₂ are then modeled by AO and SAO in global-mean K_zz. It is then shown that our estimated global-mean K_zz is lower in magnitude than the suggested global-mean K_zz from Qian et al. (2009) that can model the observed AO and SAO in the ionosphere/thermosphere (IT) region. However, our estimated global-mean K_zz is similar in magnitude with recent suggestions of global-mean K_zz in models with explicit gravity wave parameterization. Our work therefore concludes that global-mean K_zz from global-mean CO₂ profiles cannot model the observed AO and SAO in the IT region because our estimated global-mean K_zz may only be representing eddy diffusion due to gravity wave breaking. The difference between our estimated global-mean K_zz and the global-mean K_zz from Qian et al. (2009) thus represents diffusion and mixing from other nongravity wave sources not directly accounted for in the TIE-GCM lower boundary conditions. These other sources may well be the more dominant lower atmospheric forcing behind the AO and SAO in the IT region.

Salinas, Cornelius; Chang, Loren; Liang, Mao-Chang; Yue, Jia; Russell, James; Mlynczak, Martin;

Published by: Journal of Geophysical Research: Space Physics Published on: 11/2016

YEAR: 2016 DOI: 10.1002/2016JA023161

Ionospheric data assimilation with thermosphere-ionosphere-electrodynamics general circulation model and GPS-TEC during geomagnetic storm conditions

The main purpose of this paper is to investigate the effects of rapid assimilation-forecast cycling on the performance of ionospheric data assimilation during geomagnetic storm conditions. An ensemble Kalman filter software developed by the National Center for Atmospheric Research (NCAR), called Data Assimilation Research Testbed, is applied to assimilate ground-based GPS total electron content (TEC) observations into a theoretical numerical model of the thermosphere and ionosphere (NCAR thermosphere-ionosphere-electrodynamics general circulation model) during the 26 September 2011 geomagnetic storm period. Effects of various assimilation-forecast cycle lengths: 60, 30, and 10 min on the ionospheric forecast are examined by using the global root-mean-squared observation-minus-forecast (OmF) TEC residuals. Substantial reduction in the global OmF for the 10 min assimilation-forecast cycling suggests that a rapid cycling ionospheric data assimilation system can greatly improve the quality of the model forecast during geomagnetic storm conditions. Furthermore, updating the thermospheric state variables in the coupled thermosphere-ionosphere forecast model in the assimilation step is an important factor in improving the trajectory of model forecasting. The shorter assimilation-forecast cycling (10 min in this paper) helps to restrain unrealistic model error growth during the forecast step due to the imbalance among model state variables resulting from an inadequate state update, which in turn leads to a greater forecast accuracy.

Chen, C.; Lin, C.; Matsuo, T.; Chen, W.; Lee, I.; Liu, J; Lin, J.; Hsu, C.;

Published by: Journal of Geophysical Research: Space Physics Published on: 05/2016

YEAR: 2016 DOI: 10.1002/2015JA021787

Ionospheric data assimilation with thermosphere-ionosphere-electrodynamics general circulation model and GPS-TEC during geomagnetic storm conditions

The main purpose of this paper is to investigate the effects of rapid assimilation-forecast cycling on the performance of ionospheric data assimilation during geomagnetic storm conditions. An ensemble Kalman filter software developed by the National Center for Atmospheric Research (NCAR), called Data Assimilation Research Testbed, is applied to assimilate ground-based GPS total electron content (TEC) observations into a theoretical numerical model of the thermosphere and ionosphere (NCAR thermosphere-ionosphere-electrodynamics general circulation model) during the 26 September 2011 geomagnetic storm period. Effects of various assimilation-forecast cycle lengths: 60, 30, and 10 min on the ionospheric forecast are examined by using the global root-mean-squared observation-minus-forecast (OmF) TEC residuals. Substantial reduction in the global OmF for the 10 min assimilation-forecast cycling suggests that a rapid cycling ionospheric data assimilation system can greatly improve the quality of the model forecast during geomagnetic storm conditions. Furthermore, updating the thermospheric state variables in the coupled thermosphere-ionosphere forecast model in the assimilation step is an important factor in improving the trajectory of model forecasting. The shorter assimilation-forecast cycling (10 min in this paper) helps to restrain unrealistic model error growth during the forecast step due to the imbalance among model state variables resulting from an inadequate state update, which in turn leads to a greater forecast accuracy.

Chen, C.; Lin, C.; Matsuo, T.; Chen, W.; Lee, I.; Liu, J; Lin, J.; Hsu, C.;

Published by: Journal of Geophysical Research: Space Physics Published on: 05/2016

YEAR: 2016 DOI: 10.1002/2015JA021787

Impacts of SABER CO2-based eddy diffusion coefficients in the lower thermosphere on the ionosphere/thermosphere

This work estimates global‐mean K zz using Sounding of the Atmosphere using Broadband Emission Radiometry/Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics

Salinas, Cornelius; Chang, Loren; Liang, Mao-Chang; Yue, Jia; , Russell; Mlynczak, Martin;

Published by: Journal of Geophysical Research: Space Physics Published on:

YEAR: 2016 DOI: 10.1002/2016JA023161

Ionospheric data assimilation and forecasting during storms

Chartier, Alex; Matsuo, Tomoko; Anderson, Jeffrey; Collins, Nancy; Hoar, Timothy; Lu, Gang; Mitchell, Cathryn; Coster, Anthea; Paxton, Larry; Bust, Gary;

Published by: Journal of Geophysical Research: Space Physics Published on:

YEAR: 2016 DOI:

Parameterization of Nitric Oxide Emissions in the Thermosphere

Lin, CYT; Deng, Yue; Venkataramani, Karthik; Yonker, Justin; Bailey, Scott;

Published by: Published on:

YEAR: 2016 DOI:

Seasonal variability in global eddy diffusion and the effect on neutral density

We describe a method for making single-satellite estimates of the seasonal variability in global-average eddy diffusion coefficients. Eddy diffusion values as a function of time were estimated from residuals of neutral density measurements made by the Challenging Minisatellite Payload (CHAMP) and simulations made using the thermosphere-ionosphere-mesosphere electrodynamics global circulation model (TIME-GCM). The eddy diffusion coefficient results are quantitatively consistent with previous estimates based on satellite drag observations and are qualitatively consistent with other measurement methods such as sodium lidar observations and eddy diffusivity models. Eddy diffusion coefficient values estimated between January 2004 and January 2008 were then used to generate new TIME-GCM results. Based on these results, the root-mean-square sum for the TIME-GCM model is reduced by an average of 5\% when compared to density data from a variety of satellites, indicating that the fidelity of global density modeling can be improved by using data from a single satellite like CHAMP. This approach also demonstrates that eddy diffusion could be estimated in near real-time from satellite observations and used to drive a global circulation model like TIME-GCM. Although the use of global values improves modeled neutral densities, there are limitations to this method, which are discussed, including that the latitude dependence of the seasonal neutral-density signal is not completely captured by a global variation of eddy diffusion coefficients. This demonstrates the need for a latitude-dependent specification of eddy diffusion which is also consistent with diffusion observations made by other techniques.

Pilinski, M.; Crowley, G.;

Published by: Journal of Geophysical Research: Space Physics Published on: 04/2015

YEAR: 2015 DOI: 10.1002/2015JA021084

annual; eddy diffusion; neutral density; satellite drag; seasonal variability; semiannual

The Charged Aerosol Release Experiment (Care II) to Study Artificial Dusty Plasmas in the Upper Atmosphere

Bernhardt, Paul; Siefring, Carl; Gatling, George; , Briczinski; Vierinen, Juha; Bhatt, Asti; Holzworth, Robert; McCarthy, Michael; Gustavsson, Björn; La Hoz, Cesar; , others;

Published by: Published on:

YEAR: 2015 DOI:

Meteor radar wind over Chung-Li (24.9 N, 121 E), Taiwan, for the period 10--25 November 2012 which includes Leonid meteor shower: Comparison with empirical model and satellite measurements

The neutral winds in the mesosphere and lower thermosphere (MLT) region are measured by a newly installed meteor trail detection system (or meteor radar) at Chung-Li, Taiwan, for the period 10\textendash25 November 2012, which includes the Leonid meteor shower period. In this study, we use the 3 m field-aligned plasma irregularities in the sporadic E (E_s) region in combination with the International Geomagnetic Reference Field model to calibrate the system phase biases such that the true positions of the meteor trails can be correctly determined with interferometry technique. The horizontal wind velocities estimated from the radial velocities of the meteor trails and their locations by using a least squares method show that the diurnal tide dominates the variation of the MLT neutral wind with time over Chung-Li, which is in good agreement with the horizontal wind model (HWM07) prediction. However, harmonic analysis reveals that the amplitudes of the mean wind, diurnal, and semidiurnal tides of the radar-measured winds in height range 82\textendash100 km are systematically larger than those of the model-predicted winds by up to a factor of 3. A comparison shows that the overall pattern of the height-local time distribution of the composite radar-measured meteor wind is, in general, consistent with that of the TIMED Doppler Interferometer-observed wind, which is dominated by a diurnal oscillation with downward phase progression at a rate of about 1.3 km/h. The occurrences of the E_s layers retrieved from fluctuations of the amplitude and excess phase of the GPS signal received by the FORMOSAT-3/COSMIC satellites during the GPS radio occultation (RO) process are compared with the shear zones of the radar-measured meteor wind and HWM07 wind. The result shows that almost all of the RO-retrieved E_s layers occur within the wind shear zones that favor the E_s layer formation based on the wind shear theory, suggesting that the primary physical process responsible for the E_s layer events retrieved from the scintillations of the GPS RO signal is very likely the plasma convergence effect of the neutral wind shear.

Su, C.; Chen, H.; Chu, Y.; Chung, M.; Kuong, R.; Lin, T.; Tzeng, K.; Wang, C; Wu, K.; Yang, K.;

Published by: Radio Science Published on: 08/2014

YEAR: 2014 DOI: 10.1002/2013RS005273

HWM07; radar meteor wind; tide

Research on thermospheric densities derived from two-line element sets

Two-line Orbital Element Sets (TLEs) consist of mean orbital elements at epoch, along with the NORAD (North American Aerospace Defence Command) catalog number, international designator, epoch and additional fitting parameters. These information can be used to derive thermospheric densities through integration of differential equation for mean motion. For near-circular orbit satellites, derived thermospheric density can be seen as real density because of their stable orbit height, while for elliptical orbit satellites, thermospheric density at perigee and apogee can be different as much as several orders.

Tingling, Ren; Juan, Miao; Siqing, Liu; Zhitao, Li;

Published by: Journal of Space Science Published on:

YEAR: 2014 DOI:

Seasonal Variability in Global Eddy Diffusion and the Effect on Thermospheric Neutral Density

Pilinski, Marcin; Crowley, Geoff;

Published by: Published on:

YEAR: 2014 DOI:

Ensemble Assimilation Using Three First-Principles Thermospheric Models as a Tool for 72-hour Density and Satellite Drag Forecasts

Hunton, Don; Pilinski, Marcin; Crowley, Geoff; Azeem, I; Fuller-Rowell, Timothy; Matsuo, Tomoko; Fedrizzi, Mariangel; Solomon, Stanley; Qian, Liying; Thayer, Jeffrey; , others;

Published by: Published on:

YEAR: 2014 DOI:

Towards a National Space Weather Predictive Capability

Lindstrom, Kurt; Fox, Nicola; Ryschkewitsch, Michael; Anderson, Brian; Gjerloev, Jesper; Merkin, Viacheslav; Kelly, Michael; Miller, Ethan; Sitnov, Mikhail; Ukhorskiy, Aleksandr; , others;

Published by: Published on:

YEAR: 2014 DOI:

Topside Ionospheric Sounder for CubeSats

Swenson, C; Pratt, J; Fish, CS; Winkler, C; Pilinski, M; Azeem, I; Crowley, G; Jeppesen, M; Martineau, R;

Published by: Published on:

YEAR: 2014 DOI:

Space Weather Tools of the Trade-A Changing Mix

Kunches, Joseph; Crowley, Geoff; Pilinski, Marcin; Winkler, Clive; Fish, Chad; Hunton, Don; Reynolds, Adam; Azeem, I;

Published by: Published on:

YEAR: 2014 DOI:

Towards a National Space Weather Predictive Capability

Fox, NJ; Lindstrom, KL; Ryschkewitsch, MG; Anderson, BJ; Gjerloev, JW; Merkin, VG; Kelly, MA; Miller, ES; Sitnov, MI; Ukhorskiy, AY; , others;

Published by: Published on:

YEAR: 2014 DOI:

Ionospheric Data Assimilation from a Data Provider's Perspective

Schaefer, Robert; Paxton, Larry; Bust, G; Zhang, Yongliang; Romeo, Giuseppe; Comberiate, Joseph; Gelinas, Lynette;

Published by: Published on:

YEAR: 2014 DOI:

Aerodynamic Analysis Based on Challenging Minisatellite Payload Satellite Lift-to-Drag Measurements

A lift-to-drag ratio analysis is performed based on accelerometer measurements made by the Challenging Minisatellite Payload satellite to investigate the nature of gas-surface interactions taking place in orbit. The results described are for the November\ 2002 satellite yaw maneuver. At this time, the satellite flew at a mean altitude of 407\ km. Two types of gas\textendashsurface interaction are considered in the analysis. The first is a cosine (fully diffuse) reflection model with incomplete energy accommodation. The second is a blended cosine reflection model having full accommodation combined with a fraction of quasi-specular reflection having an accommodation coefficient dependent on the surface material. It is found that the fully diffuse model best reproduces the satellite data during the yaw maneuver, and that the accommodation coefficient is approximately 0.89 during this time.

Pilinski, Marcin; Argrow, Brian;

Published by: Journal of Spacecraft and Rockets Published on: 11/2013

YEAR: 2013 DOI: 10.2514/1.A32394

Thermospheric tidal effects on the ionospheric midlatitude summer nighttime anomaly using SAMI3 and TIEGCM

This paper is the first study to employ a three-dimensional physics-based ionosphere model, SAMI3, coupled with the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) and Global Scale Wave Model to simulate the mesospheric and lower thermospheric tidal effects on the development of midlatitude summer nighttime anomaly (MSNA). Using this coupled model, the diurnal variation of MSNA electron densities at 300 km altitude is simulated on both June solstice (day of year (DOY) 167) and December solstice (DOY 350) in 2007. Results show successful reproduction of the southern hemisphere MSNA structure including the eastward drift feature of the southern MSNA, which is not reproduced by the default SAMI3 runs using the neutral winds provided by the empirical Horizontal Wind Model 93 neutral wind model. A linear least squares algorithm for extracting tidal components is utilized to examine the major tidal component affecting the variation of southern MSNA. Results show that the standing diurnal oscillation component dominates the vertical neutral wind manifesting as a diurnal eastward wave-1 drift of the southern MSNA in the local time frame. We also find that the stationary planetary wave-1 component of vertical neutral wind can cause diurnal variation of the summer nighttime electron density enhancement around the midlatitude ionosphere.

Chen, C.; Lin, C.; Chang, L.; Huba, J.; Lin, J.; Saito, A.; Liu, J;

Published by: Journal of Geophysical Research: Space Physics Published on: 06/2013

YEAR: 2013 DOI: 10.1002/jgra.50340

MSNA; SAMI3; tidal effect; TIEGCM

Thermospheric tidal effects on the ionospheric midlatitude summer nighttime anomaly using SAMI3 and TIEGCM

This paper is the first study to employ a three-dimensional physics-based ionosphere model, SAMI3, coupled with the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) and Global Scale Wave Model to simulate the mesospheric and lower thermospheric tidal effects on the development of midlatitude summer nighttime anomaly (MSNA). Using this coupled model, the diurnal variation of MSNA electron densities at 300 km altitude is simulated on both June solstice (day of year (DOY) 167) and December solstice (DOY 350) in 2007. Results show successful reproduction of the southern hemisphere MSNA structure including the eastward drift feature of the southern MSNA, which is not reproduced by the default SAMI3 runs using the neutral winds provided by the empirical Horizontal Wind Model 93 neutral wind model. A linear least squares algorithm for extracting tidal components is utilized to examine the major tidal component affecting the variation of southern MSNA. Results show that the standing diurnal oscillation component dominates the vertical neutral wind manifesting as a diurnal eastward wave-1 drift of the southern MSNA in the local time frame. We also find that the stationary planetary wave-1 component of vertical neutral wind can cause diurnal variation of the summer nighttime electron density enhancement around the midlatitude ionosphere.

Chen, C.; Lin, C.; Chang, L.; Huba, J.; Lin, J.; Saito, A.; Liu, J;

Published by: Journal of Geophysical Research: Space Physics Published on: 06/2013

YEAR: 2013 DOI: 10.1002/jgra.50340

MSNA; SAMI3; tidal effect; TIEGCM

Semi-Empirical Satellite Accommodation Model for Spherical and Randomly Tumbling Objects

Orbits of launch-vehicle upper stages and spheres were observed by U.S. Air Force Space Command, and the resulting observations were converted by the Space Analysis Office to fitted ballistic coefficients by comparing the observed orbit with an orbit predicted by an atmospheric-drag model. The ballistic coefficients contain signals that result from atmospheric variability not captured by the model as well as signals that correspond to changes in the satellite-drag coefficient. For objects in highly elliptical orbits with perigee altitudes below 200\ km a 50\% change in ballistic coefficient can be observed. This drastic change is associated with both changes in the energy accommodation coefficient driven by atomic-oxygen adsorption and entry into a transition flow region where a diffuse shock forms ahead of the satellite near perigee. Furthermore, the observed ballistic coefficients for objects in near-circular orbits (7.5 km/s speeds) do not match those of objects in highly eccentric orbits (10 km/s speeds near perigee). This difference is attributed to a decrease in adsorption efficiency postulated by previous researchers that is formalized in this work into a semi-empirical model. The model parameters suggest that the average binding energy of atomic oxygen on satellite surfaces is about 5.7\ eV.

Pilinski, Marcin; Argrow, Brian; Palo, Scott; Bowman, Bruce;

Published by: Journal of Spacecraft and Rockets Published on: 05/2013

YEAR: 2013 DOI: 10.2514/1.A32348

The Science of the Global-scale measurements of the Limb and Disk (GOLD) Mission

Burns, AG; Eastes, R; McClintock, WE; Solomon, SC; Anderson, DN; Andersson, L; Codrescu, M; Daniell, RE; Harvey, J; Krywonos, A; , others;

Published by: Published on:

YEAR: 2013 DOI:

The impact of helium on thermosphere mass density response to geomagnetic activity during the recent solar minimum

Thayer, J.; Liu, X.; Lei, J.; Pilinski, M.; Burns, A.;

Published by: Journal of Geophysical Research Published on: Jan-01-2012

YEAR: 2012 DOI: 10.1029/2012JA017832

Ionospheric plasma caves under the equatorial ionization anomaly

This paper reports the existence of plasma caves, minima in the electron density located at 5\textendash10\textdegree to the magnetic equator, in the bottomside ionosphere based on electron densities simulations from the International Reference Ionosphere (IRI-2007) and clear evidences given by plasma density and drift measurements of the Dynamic Explorer 2 (DE 2) satellite during 1981\textendash1983. The IRI simulations suggest plasma caves as daytime features (08:00\textendash19:00 LT; length of 18,158 km in the longitudinal direction), that range from theE region up to about 300 km altitude with 10\textdegree (or 1100 km) width in the latitudinal direction. In situ measurements of the ion and electron densities probed by the DE 2 confirm the existence of the plasma caves at low altitudes of the EIA ionosphere. The unexpected downward and upward (or weakly and strongly upward) ion drifts at the magnetic equator and the two off equators seem to play an important role responsible for the plasma cave formation.

Lee, I.; Liu, J; Lin, C.; Oyama, K.-I.; Chen, C; Chen, C.;

Published by: Journal of Geophysical Research Published on: 11/2012

YEAR: 2012 DOI: 10.1029/2012JA017868

Dynamic Explorer 2; Equatorial ionization anomaly; plasma cave

Assimilation of FORMOSAT-3/COSMIC electron density profiles into a coupled thermosphere/ionosphere model using ensemble Kalman filtering

This paper presents our effort to assimilate FORMOSAT-3/COSMIC (F3/C) GPS Occultation Experiment (GOX) observations into the National Center for Atmospheric Research (NCAR) Thermosphere Ionosphere Electrodynamics General Circulation Model (TIE-GCM) by means of ensemble Kalman filtering (EnKF). The F3/C electron density profiles (EDPs) uniformly distributed around the globe which provide an excellent opportunity to monitor the ionospheric electron density structure. The NCAR TIE-GCM simulates the Earth\textquoterights thermosphere and ionosphere by using self-consistent solutions for the coupled nonlinear equations of hydrodynamics, neutral and ion chemistry, and electrodynamics. The F3/C EDP are combined with the TIE-GCM simulations by EnKF algorithms implemented in the NCAR Data Assimilation Research Testbed (DART) open-source community facility to compute the expected value of electron density, which is \textquoteleftthe best\textquoteright estimate of the current ionospheric state. Assimilation analyses obtained with real F3/C electron density profiles are compared with independent ground-based observations as well as the F3/C profiles themselves. The comparison shows the improvement of the primary ionospheric parameters, such as NmF2 and hmF2. Nevertheless, some unrealistic signatures appearing in the results and high rejection rates of observations due to the applied outlier threshold and quality control are found in the assimilation experiments. This paper further discusses the limitations of the model and the impact of ensemble member creation approaches on the assimilation results, and proposes possible methods to avoid these problems for future work.

Lee, I.; Matsuo, T.; Richmond, A.; Liu, J; Wang, W.; Lin, C.; Anderson, J.; Chen, M.;

Published by: Journal of Geophysical Research Published on: 10/2012

YEAR: 2012 DOI: 10.1029/2012JA017700

data assimilation; ensemble Kalman filter; FORMOSAT-3/COSMIC; Ionosphere

Long-term variations of the nighttime electron density enhancement during the ionospheric midlatitude summer

This study, for the first time, presented the long-term variations of Midlatitude Summer Nighttime Anomaly (MSNA) in the two hemispheres by using 66 ground-based ionosonde observations from 1957 to 2010. MSNA is characterized by the feature of higher nighttime electron density than daytime density in the midlatitude region during local summer months. Observations from 66 ionosonde stations were used to calculate the MSNA index which is defined by the difference between nighttime and noontime NmF2 values. The MSNA occurrence is determined by positive value of the MSNA index. The global distribution map of the MSNA index shows that there are three regions of intense MSNA. Three ionosonde stations in each of active MSNA regions were chosen to study the long-term variation of MSNA covering longer than one solar cycle. One station in the southern hemisphere is AIJ6N (Argentine IS; 65.2\textdegreeS, 64.3\textdegreeW geographic) and two stations in the northern hemisphere are LN047 (Lannion; 48.8\textdegreeN, -3.4\textdegreeE geographic) and MG560 (Magadan; 60.0\textdegreeN, 151.0\textdegreeE geographic). Results show that there is a clear solar activity negative dependence of the MSNA index, high MSNA in the low solar activity condition and low MSNA in the high solar activity condition. The seasonal and solar activity variations of the MSNA index are explained by the combined effects of the vertical plasma drift induced by the neutral wind and photoionization during the nighttime.

Chen, C.; Saito, A.; Lin, C.; Liu, J;

Published by: Journal of Geophysical Research Published on: 07/2012

YEAR: 2012 DOI: 10.1029/2011JA017138

ionization-uplift effect; midlatitude summer nighttime anomaly; MSNA index

Observations of global ionospheric responses to the 2009 stratospheric sudden warming event by FORMOSAT-3/COSMIC

The global ionospheric response to a stratospheric sudden warming (SSW) is studied using three-dimensional electron density maps derived from radio occultation observations of FORMOSAT-3/COSMIC during the 2009 SSW periods. Results show that the ionospheric electron density at EIA crests exhibit a morning/early afternoon increase followed by an afternoon decrease and an evening increase, indicative of a semidiurnal component during the SSW period, which is consistent with recent studies. The latitude-altitude electron density slice maps show that the SSW related modifications of the equatorial plasma fountain interact with the existing summer-to-winter neutral winds and resulting in a north\textendashsouth asymmetry. The global ionospheric response shows a clear longitudinal dependence in the equatorial plasma fountain enhancement during morning/early afternoon, inferred from the duration of the equatorial ionization anomaly (EIA) enhancement. Following the enhancement, prominent global EIA reductions resulting from the equatorial plasma fountain weakening in the afternoon sector are seen. The ionospheric response to the 2009 SSW event is also compared with the usual seasonal variation during January\textendashFebruary 2007. Instead of showing the electron density increase in the northern hemisphere and decrease in the southern hemisphere as the usual seasonal variation does, the SSW period ionosphere shows prominent global electron density reductions in the afternoon period during the 2009 SSW event.

Lin, C.; Lin, J.; Chang, L.; Liu, J; Chen, C.; Chen, W.; Huang, H.; Liu, C.;

Published by: Journal of Geophysical Research Published on: 06/2012

YEAR: 2012 DOI: 10.1029/2011JA017230

FORMOSAT-3/COSMIC; ionospheric responses to stratospheric sudden warming

Observations of global ionospheric responses to the 2009 stratospheric sudden warming event by FORMOSAT-3/COSMIC

The global ionospheric response to a stratospheric sudden warming (SSW) is studied using three-dimensional electron density maps derived from radio occultation observations of FORMOSAT-3/COSMIC during the 2009 SSW periods. Results show that the ionospheric electron density at EIA crests exhibit a morning/early afternoon increase followed by an afternoon decrease and an evening increase, indicative of a semidiurnal component during the SSW period, which is consistent with recent studies. The latitude-altitude electron density slice maps show that the SSW related modifications of the equatorial plasma fountain interact with the existing summer-to-winter neutral winds and resulting in a north\textendashsouth asymmetry. The global ionospheric response shows a clear longitudinal dependence in the equatorial plasma fountain enhancement during morning/early afternoon, inferred from the duration of the equatorial ionization anomaly (EIA) enhancement. Following the enhancement, prominent global EIA reductions resulting from the equatorial plasma fountain weakening in the afternoon sector are seen. The ionospheric response to the 2009 SSW event is also compared with the usual seasonal variation during January\textendashFebruary 2007. Instead of showing the electron density increase in the northern hemisphere and decrease in the southern hemisphere as the usual seasonal variation does, the SSW period ionosphere shows prominent global electron density reductions in the afternoon period during the 2009 SSW event.

Lin, C.; Lin, J.; Chang, L.; Liu, J; Chen, C.; Chen, W.; Huang, H.; Liu, C.;

Published by: Journal of Geophysical Research Published on: 06/2012

YEAR: 2012 DOI: 10.1029/2011JA017230

FORMOSAT-3/COSMIC; ionospheric responses to stratospheric sudden warming

Study on Far Ultraviolet Imaging Spectrometer with Grating Dispersion for Atmosphere Remote Sensing

The far ultraviolet imaging spectrometer with grating dispersion is mainly used in the detection of the ionosphere, thermosphere, auroral zone and glow zone. It is important for the study and application of the remote sensing of atmosphere in China. We designed two optical systems for the far ultraviolet imaging spectrometer, and obtained the plane grating structure prototype based on the principles of nadir and limb atmospheric sounding. The prototype working at the waveband of 120~180 nm consists of an off-axis parabolic mirror and an advanced Czerny-Turner spectral imaging system. The far ultraviolet response back-illuminating CCD is adopted as the detector. The corresponding experiment system was built to calibrate the basic performances of the spectrometer prototype. The spectral and spatial resolutions are 2 nm and 0.5 mrad respectively. The far ultraviolet imaging spectrometer prototype plays an important role in the study and application of atmospheric remote sensing.

Yu, L.; Wang, S.; Lin, G.; Qu, Y.; Wang, L.;

Published by: Spectroscopy and Spectral Analysis Published on: 03/2012

YEAR: 2012 DOI:

Extreme Ultraviolet Variability Experiment (EVE) on~the~Solar Dynamics Observatory (SDO): Overview~of~Science Objectives, Instrument Design, Data~Products, and Model Developments

The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth\textquoterights upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105\ nm with unprecedented spectral resolution (0.1\ nm), temporal cadence (ten seconds), and accuracy (20\%). EVE includes several irradiance instruments: The Multiple EUV Grating Spectrographs (MEGS)-A is a grazing-incidence spectrograph that measures the solar EUV irradiance in the 5 to 37\ nm range with 0.1-nm resolution, and the MEGS-B is a normal-incidence, dual-pass spectrograph that measures the solar EUV irradiance in the 35 to 105\ nm range with 0.1-nm resolution. To provide MEGS in-flight calibration, the EUV SpectroPhotometer (ESP) measures the solar EUV irradiance in broadbands between 0.1 and 39\ nm, and a MEGS-Photometer measures the Sun\textquoterights bright hydrogen emission at 121.6\ nm. The EVE data products include a near real-time space-weather product (Level\ 0C), which provides the solar EUV irradiance in specific bands and also spectra in 0.1-nm intervals with a cadence of one minute and with a time delay of less than 15\ minutes. The EVE higher-level products are Level\ 2 with the solar EUV irradiance at higher time cadence (0.25\ seconds for photometers and ten seconds for spectrographs) and Level\ 3 with averages of the solar irradiance over a day and over each one-hour period. The EVE team also plans to advance existing models of solar EUV irradiance and to operationally use the EVE measurements in models of Earth\textquoterights ionosphere and thermosphere. Improved understanding of the evolution of solar flares and extending the various models to incorporate solar flare events are high priorities for the EVE team.

Woods, T.; Eparvier, F.; Hock, R.; Jones, A.; Woodraska, D.; Judge, D.; Didkovsky, L.; Lean, J.; Mariska, J.; Warren, H.; McMullin, D.; Chamberlin, P.; Berthiaume, G.; Bailey, S.; Fuller-Rowell, T.; Sojka, J.; Tobiska, W.; Viereck, R.;

Published by: Solar Physics Published on: 01/2012

YEAR: 2012 DOI: 10.1007/s11207-009-9487-6

EVE; SDO; Solar EUV irradiance; Space weather research

Extreme Ultraviolet Variability Experiment (EVE) on~the~Solar Dynamics Observatory (SDO): Overview~of~Science Objectives, Instrument Design, Data~Products, and Model Developments

The highly variable solar extreme ultraviolet (EUV) radiation is the major energy input to the Earth\textquoterights upper atmosphere, strongly impacting the geospace environment, affecting satellite operations, communications, and navigation. The Extreme ultraviolet Variability Experiment (EVE) onboard the NASA Solar Dynamics Observatory (SDO) will measure the solar EUV irradiance from 0.1 to 105\ nm with unprecedented spectral resolution (0.1\ nm), temporal cadence (ten seconds), and accuracy (20\%). EVE includes several irradiance instruments: The Multiple EUV Grating Spectrographs (MEGS)-A is a grazing-incidence spectrograph that measures the solar EUV irradiance in the 5 to 37\ nm range with 0.1-nm resolution, and the MEGS-B is a normal-incidence, dual-pass spectrograph that measures the solar EUV irradiance in the 35 to 105\ nm range with 0.1-nm resolution. To provide MEGS in-flight calibration, the EUV SpectroPhotometer (ESP) measures the solar EUV irradiance in broadbands between 0.1 and 39\ nm, and a MEGS-Photometer measures the Sun\textquoterights bright hydrogen emission at 121.6\ nm. The EVE data products include a near real-time space-weather product (Level\ 0C), which provides the solar EUV irradiance in specific bands and also spectra in 0.1-nm intervals with a cadence of one minute and with a time delay of less than 15\ minutes. The EVE higher-level products are Level\ 2 with the solar EUV irradiance at higher time cadence (0.25\ seconds for photometers and ten seconds for spectrographs) and Level\ 3 with averages of the solar irradiance over a day and over each one-hour period. The EVE team also plans to advance existing models of solar EUV irradiance and to operationally use the EVE measurements in models of Earth\textquoterights ionosphere and thermosphere. Improved understanding of the evolution of solar flares and extending the various models to incorporate solar flare events are high priorities for the EVE team.

Woods, T.; Eparvier, F.; Hock, R.; Jones, A.; Woodraska, D.; Judge, D.; Didkovsky, L.; Lean, J.; Mariska, J.; Warren, H.; McMullin, D.; Chamberlin, P.; Berthiaume, G.; Bailey, S.; Fuller-Rowell, T.; Sojka, J.; Tobiska, W.; Viereck, R.;