Paper

<Author>

Huixin Liu, H. Lühr, V. Henize, W. Köhler

<Published Magazines>

J. Geophys. Res , vol.110, A04301, doi:10.1029/2004JA010741, 2005

<Explanation>

A paper that discovered the thermospheric equatorial anomaly and showed for the first time in the world the atmosphere-plasma interaction in a weakly ionized medium. The paper pointed out that the superatmosphere is neutral but strongly influenced by the geomagnetic field, and revealed for the first time that the magnetic field dominates the behavior of the neutral atmosphere through the neutral atmosphere-plasma interaction, giving a new perspective on thermospheric ionospheric dynamics. In addition, the accelerometer-based thermospheric observation method developed by the applicant has greatly stimulated research on the rarefied neutral atmosphere, which is difficult to observe, and has become a pillar of recent research on the upper atmosphere.

<Overview>

A global distribution of the thermospheric total mass density at 400 km altitude is derived from the high-accuracy accelerometer on board the CHAMP satellite with good temporal and spatial coverage. It shows two interesting features. One is the anomalous distribution at low latitudes. Instead of maximizing at the dayside equator, the thermospheric density shows maxima at about 20°–25° geomagnetic latitude on both sides of the equator between 10 and 20 magnetic local time. This latitudinal distribution resembles fairly well the equatorial ionization anomaly, thus indicating strong magnetic control of the thermospheric mass density via ionosphere-thermosphere coupling. The thermospheric density shows a secondary maximum at the nightside equator shortly before midnight, in reminiscence of the well-known thermospheric midnight temperature maximum. Another feature to notice is that the thermospheric density is highly structured at high latitudes, with localized density enhancements possibly related to Joule/particle heating. This structure is, however, different from the cellular structure recognized by the National Center for Atmospheric Research thermosphere general circulation model at altitudes of 120–300 km. This indicates that the exact cellular structure may not necessarily extend to 400 km. A comparison between observations and the Mass Spectrometer Incoherent Scatter 1990 (MSIS90) model predictions shows that although the model describes the general structure of the observed density reasonably well, it misses the double peaks at low latitudes completely. This causes an underestimation of the total mass density by 15–20% in the crest region. At high latitudes an underestimation of 20–30% occurs in the midnight sector and the cusp region.

<Author>

Huixin Liu, H. Lühr

<Published Magazines>

J. Geophys. Res , vol.110, A09S29, doi:10.1029/2004JA010908, 2005.

<Explanation>

太陽フレアと大磁気嵐に対する超高層大気の応答の全球的拳動と極域から赤道への伝搬を明らかにした論文。宇宙天気における熱圏の応答の普遍性と多様性を示しと同時に、衛星軌道と運用への社会的影響を指摘した。

<Author>

Huixin Liu, E. Doornbos, M. Yamamoto, S. T. Ram,

<Published Magazines>

Geophys. Res. Lett., 38, L12102, doi:10.1029/2011GL047898, 2011

<Explanation>

This is a paper on the discovery of the thermospheric cold phenomenon in response to stratospheric sudden temperature rise. The important role of the thermosphere in producing ionospheric variations for stratospheric sudden warming is clarified.

<Overview>

Thermospheric density simultaneously observed by the CHAMP and GRACE satellites in both the pre‐dawn and afternoon local time sectors undergoes significant decrease across both hemispheres during the major stratospheric sudden warming (SSW) in January 2009. This decrease is largest in the equatorial region near the subsolar latitude, reaching ∼30% at 325 km, and 45% at 475 km altitude in the afternoon sector. This large density drop demonstrates a substantial cooling of about 50 Kelvin in the equatorial upper thermosphere. Furthermore, the cooling varies clearly with longitude in terms of magnitude and the timing of the maximum cooling. Thermosphere cooling can have important impact on the ionosphere, as indicated by simultaneous plasma observations. Though many questions remain about what causes the cooling, our results open a new perspective for investigating the global coupling of the lower and upper atmosphere during SSWs.

1. Vanhamaki, H., A. Maute, P. Alken, Huixin Liu, Dipolar elementary current systems for ionospheric current reconstruction at low and middle latitudes, Earth, Planets and Space, 2020, in press

2. Huixin Liu, C. Tao, H. Jin, Y. Nakamoto, Circulation and tides in a cooler upper atmosphere: dynamical effects of CO2-doubling, Geophys. Res. Lett., 47, e2020GL087413, 1-9, https:// doi.org/10.1002/2020GL087413, 2020.

3. Yu, T. H. Ye, Huixin Liu, C. Xia, X. Zuo, X. Yan, N. Yang, Y. Sun, B. Zhao, Ionospheric F-layer scintillation weakening as observed by COSMIC/FORMOSAT-3 during the major sudden stratospheric warming in January 2013, J. Geophys. Res., 125, https:// doi.org/10.1002/2019JA027721, 2020.

4. Zhang, R., L. Liu, Huixin Liu, Interhemispheric transport of the ionospheric F region plasma during the 2009 sudden stratosphere warming, Geophys. Res. Lett., 47, e2020GL087078, https:// doi.org/10.1002/2020GL087078, 2020.

5. Aryal, S., J. S. Evans, J. Correira, T. Dang, J. Lei, Huixin Liu, G. Jee, A. G. Burns, W. Wang, S. C. Solomon, F. I. Laskar, W. E. McClintock, R. W. Eastes, First global-scale synoptic imaging of a solar eclipse in the thermosphere, J. Geophys. Res., 125, e2020JA027789, https:// doi.org/10.1002/2020JA027789, 2020. (not in pure)

6. Baron, P. S. Ochiai, E. Dupuy, R. Larsson, H, Huixin Liu, N. Manago, D. Murtagh, S. Oyama, H. Sagawa, A. Saito, T. Sakazaki, M. Shiotani, M. Suzuki, Potential for the measurement of mesosphere and lower thermosphere (MLT) wind, temperature, density and geomagnetic field with Superconducting Submillimeter-Wave Limb-Emission Sounder 2 (SMILES-2), Atmosphere Measurement Techniques, 23, 219-237, https://doi.org/10.5194/amt-13-219-2020, 2020.

7. Hayakawa, H., F. Clette, T. Horaguchi, Nakajima, D. Knipp, Huixin Liu, Sunspot observations by Hisako Koyama: 1945-1996, Monthly Notice of Royal Astronomical Society, 492, 4513-4527, https://doi.org/10.1093/mnras/stz3345, 2020.

8. Lugaz, N., D. J. Knipp, J. Gannon, M. Hapgood., H. Liu, T. P. O’Brien, D. Welling, Thank you to our 2019 reviewers, https://doi.org/10.1029/2020SW002481, 2020.

9. Cai, Y., X. Yue, W. Wang, S. Zhang, L. Liu, Huixin Liu, W. Wan, Long-term trend of topside ionospheric electron density derived from DMSP data during 1995-2017, J. Geophys. Res., 124, https://doi.org/10.1029/2019JA027522, 2019.

10. Yokoyama, T., H. Jin, H. Shinagawa, Huixin Liu, Seeding of equatorial plasma bubbles by vertical neutral wind, Geophys. Res. Lett., 46, 7088-7095, doi: 10.1002/2019GL083629, 2019.

11. Yamamoto, M., W. Hocking, S. Nozawa, J. Vierinen, Huixin Liu, N. Nishitani, Special issue “Recent advances in MST and EISCAT/ionospheric studies- special issue of the joint MST15 and EISCAT 18 meetings, May 2017”, Earth, Planets and Space, https://doi.org/10.1186/s40623-019-1070-2, 2019.

12. Weng, L, J. Lei, Huixin Liu, X. Dou, H. Fang, Thermosphere density cells at high latitudes as observed by GOCE satellite: preliminary results, Geophys. Res. Lett., 46, doi: 10.1002/2019GL084951, 2019.

13. Wang, Z., Huixin Liu, J. Shi, G. Wang, X. Wang, Plasma blobs concurrently observed with bubbles in the Asian-Oceanian sector during solar maximum, J. Geophys. Res., 124, ??, doi: 10.1002/2018JA026373, 2019.

14. Y. Sun, Huixin Liu, Y. Miyoshi, L. Chang, L. Liu, El Nino-Southern Oscillation effect on ionospheric tidal/SPW amplitude in 2007-2015 FORMOSAT-3/COSMIC observations, Earth, Planets and Space, 71:35, 1-9, https://doi.org/:10.1186/s40623-019-1009-7, 2019.

15. Hocke, K., Huixin Liu, N. Pedatella, G. Ma, Global sounding of F region irregularities by COSMIC during a geomagnetic storm, Annales Geophysicae, 37, 235-242, https://doi.org/10.5194/angeo-37-235-2019.

16. Huixin Liu, M. Tsutsumi, Hanli Liu, Vertical structure of terdiurnal tides in the Antarctic MLT region: 15-year observation over Syowa (69S, 39E), Geophys. Res. Lett., 46, 2364-2371, doi: 10.1002/2019GL082155, 2019.

17. Moral, A. C., K. Shiokawa, S. Suzuki, Huixin Liu, Y. Otsuka, C. Y. Yatini, Observations of low-latitude travelling ionospheric disturbances by a 630.0-nm airglow imager and the CHAMP satellite over Indonesia, J. Geophys. Res., 124, 1-15, doi: 10.1002/2018JA025634, 2019.

18. Oyama, K., C. H. Chen, L. Bankov, D. Minakshi, K. Ryu, J.Y. Liu, Huixin Liu, Precursor effect of March 11 2011 off the coast of Tohoku earthquake on high and low latitude ionospheres and its possible disturbing mechanism, Advances in Space Research, doi:10.1016/j.asr.2018.12.042, 2019.

19. M. Nakamura, D. Titov, K. McGouldrick, P. Drossart, J.L. Bertaux, Huixin Liu, Akatsuki at Venus: the first year of scientific operation, Earth, Planets and Space, 70:144, 1-3, https://doi.org/:10.1186/s40623-018-0916-3, 2018.

20. R. Shi, B. Ni, D. Summers, Huixin Liu, Y. Yoshikawa, B. Zhang, Generation of electron acoustic waves in the topside ionosphere from coupling with kinetic Alfven waves: a new electron energization mechanism, Geophys. Res. Lett., 45, 5299-5304, doi: 10.1002/2018GL077898, 2018.

21. Y. Yamazaki, C. Stolle, J. Matzka, Huixin Liu, C. Tao, Interannual variability of the equatorial ionospheric electric field, J. Geophys. Res., 123, 4241-4256, doi: 10.1002/2017JA025165, 2018.

22. Y. Sun, Huixin Liu, Y. Miyoshi, L. Liu, L. Chang, El Nino-Southern Oscillation effect on quasi-biennial oscillations of temperature diurnal tides in the mesosphere and lower thermosphere, Earth, Planets and Space, 70:85, 1-10, https://doi.org/:10.1186/s40623-018-0832-6, 2018.

23. Huixin Liu, N. Pedatella, K. Hocke, Medium-scale gravity wave perturbations in the bottomside F region in tropical regions, Geophys. Res. Lett., 44, 7099-7105, doi: 10.1002/2017GL073855, 2017.

24. Huixin Liu, J. Thayer, Y. Zhang, W. Lee, The non-storm time corrugated upper thermosphere: What's beyond MSIS, Space Weather, 15, 746-760, doi: 10.1002/2017SW001618, 2017.

25. Huixin Liu, Y. Sun, Y. Miyoshi, H. Jin, ENSO effects on MLT diurnal tides: A 21 year reanalysis data-driven GAIA model simulation, J. Geophys. Res., 122, 5539-5549, doi: 10.1002/2017JA024011, 2017.

26. Knipp, D., Huixin Liu, H. Hayakawa, Ms. Hisako Koyama: from amateur astronomer to long-term solar observer, Space Weather, 15, doi: 10.1002/2017SW001704, 2017.

27. Y. Yamazaki, Huixin Liu, Y. Sun, Y. Miyoshi, M. Kosch, M. G. Mlynczak, Quasi-biennial oscillation of the ionospheric wind dynamo, J. Geophys. Res., 122, 1-17, doi: 10.1002/2016JA023684, 2017.

28. L. Liu, Huixin Liu, H. Le, Y. Chen, Y. Sun, B. Ning, L. Hu, W. Wan, N. Li, J. Xiong, Mesospheric temperatures estimated from the meteor radar observations at Mohe, China, J. Geophys. Res., 122, 2249-2259, doi: 10.1002/2016JA023776, 2017.

29. L. Liu, Huixin Liu, Y. Chen, H. Le, Y.-Y. Sun, B. Ning, L. Hu, and W. Wan, Variations of the meteor echo heights at Beijing and Mohe, China, J. Geophys. Res., 122, 1117-1127, doi: 10.1002/ 2016JA023448, 2017.

30. Hamid, N. S. A., Huixin Liu, T. Uozumi, A. Yoshikawa, N. M. N., Peak time of equatorial electrojet from different longitude sectors during fall solar minimum, J. of Physics, 852, 1-6, doi:10.1088/1742-6596/852/1/012015, 2017.

31. Eswaraiah, S., Y. H. Kim, Huixin Liu, M. V. Ratnam, J. Lee, Do minor sudden stratophseric warmings in the southern hemisphere impact coupling between stratosphere and mesosphere-lower thermosphere like major warmings? Earth. Planets and Space, 69:119, 1-8, doi:10.1186/s40623-017-0704-5, 2017.

32. Abadi, P., Y. Otsuka, K. Shiokawa, A. Husin, H. Liu, S. Saito, Equinoctial asymmetry in the zonal distribution of scintillation as observed by GPS receivers in Indonesia, J. Geophys. Res., 122, doi: 10.1002/2017JA024146, 2017.

33. Liu, H., E. Doornbos, J. Nakashima, Thermospheric wind observed by GOCE: wind jets and seasonal variations, J. Geophys. Res., 121, 1-13, doi:10.1002/2016JA022938, 2016.

34. Liu, H., Thermospheric inter-annual variability and its potential connection to ENSO and stratospheric QBO, Earth. Planets and Space, 68:77, 1-10, doi:10.1186/s40623-016-0455-8, 2016.

35. Guo, J., F. Wei, X. Feng, J. M. Forbes, Y. Wang, Huixin Liu, W. Wan, Z. Yang, C. Liu, Prolonged multiple excitation of large-scale traveling atmospheric disturbances (TADs) by successive and interacting coronal mass ejections, J. Geophys. Res., 121, 2662-2668, doi:10.1002/2015JA022076, 2016.

36. Oyama, K.-I., M. Devi, K. Ryu, C. H. Chen, J. Y. Liu, Huixin Liu, L. Bankov, T. Kodama, Modifications of the ionosphere prior to large earthquakes: report from the ionosphere precursor study group, Geosci. Lett., 2016, 3:6, 1-10, doi:10.1186/s40562-016-0038-3, 2016.

37. Guo, J., F. Wei, X. Feng, Huixin Liu, W. Wan, Z. Yang, J. Yao, and C. Liu, Alfvén waves as a solar-interplanetary driver of the thermospheric disturbances, Scientific Reports, 6:18896, 1-6, doi:10.1038/srep-18895, 2016.

38. Ryu, K., K. Oyama, L. Bankov, C. Chen, M. Devi, Huixin Liu, J. Liu, Precursory enhancement of EIA in the morning sector: contribution from Mid-latitude large earthquake in the north-east Asian region, Adv. in Space. Res., 57, 268-280, http://dx.doi.org/10.1016/j.asr.2015.08.030, 2016.

39. Guo, J., J. Forbes, F. Wei, X. Feng, Huixin Liu, W. Wan, Z. Yang, and C. Liu, B. Amery, Y. Deng, Observations of a large-scale gravity wave propagating over an extremely large horizontal distance in the thermosphere, Geophys. Res. Lett., 42, 6560–6565, doi:10.1002/2015GL065671, 2015.

40. Hamid, N. S. A., Huixin Liu, T. Uozumi, et al., Empirical model of equatorial electrojet based on ground-based magnetometer data during solar minimum in fall, Earth. Planets and Space, 67:205, doi:10.1186/s40623-015-0373-1, 2015.

41. Hamid, N. S. A., Huixin Liu, T. Uozumi, G. K. Gopir, H. A. Hadin, A. Yoshikawa, Longitudinal and Solar Activity Dependence of Equatorial Electrojet At Southeast Asian Sector, IEEE Proc. of the 2015 IconSpace, 262-266, 2015.

42. Chang, L., Huixin Liu, Y. Miyoshi, C. Chen, F. Chang, C. Lin, J. Liu, Y. Sun, Structure and origins of the Weddell Sea Anomaly from tidal and planetary wave signatures in FORMOSAT-3/COSMIC observations and GAIA GCM simulations, J. Geophys. Res., 120, 1325-1340, doi:10.1002/2014JA020752, 2015.

43. Jusho M. H., F. Kasran, Huixin Liu, K. Yumoto, Possible correlation between exogenous parameters and seismicity, Proceedings of IEEE 7th international conference on recent advances in space technologies (RAST), 525-529, 2015.

44. Cardinal, M. G., A. Yoshikawa, H. Kawano, Huixin Liu, M. Watanabe, S. Abe, T. Uozumi, G. Maeda, T. Hada, K. Yumoto, Capacity building: A tool for advancing space weather science, Space Weather Quarterly, 12, doi:10.1002/2014SW001110, 16-20, 2015.

45. Huixin Liu, Y. Miyoshi, S. Miyahara, H. Jin, H. Fujiwara, H. Shinagawa, Thermal and dynamical changes of the zonal mean state of the thermosphere during SSW: GAIA model simulations, J. Geophys. Res., 119, doi:10.1002/2014JA020222, 6784-6791, 2014.

46. Stolle, C., Huixin Liu, Chapter 21: Low-latitude ionosphere and thermosphere: decadal observations from the CHAMP mission, in Geophysical Monograph Series 201: Modeling the Ionosphere-Thermosphere System, edited by J. D. Huba, R. W. Schunk, and G. V. Khazanov, doi:10.1002/9781118704417.ch21, 2014.

47. Oyama, K.-I., J. T. Jhou, J. T. Lin, C. Lin, Huixin Liu, K. Yumoto, Ionospheric response to 2009 Sudden Stratospheric Warming in the northern hemisphere, J. Geophys. Res., 119, doi:10.1002/2014JA020014, 2014.

48. Lin, C. H., J. T. Lin, C. H. Chen, J. Y. Liu, Y. Y. Sun, Y. Kakinami, M. Matsumura, W. H. Chen, Huixin Liu, R. J. Rau, Ionospheric shock waves triggered by Rockets, Ann. Geophys., doi:10.5194/angeo-32-1145-2014, 2014.

49. Guo, J., Huixin Liu, X. Feng, W. Wan, Y. Deng, and C. Liu, Constructive interference of large-scale gravity waves excited by interplanetary shock on 29 Octobor 2003: CHAMP observations, J. Geophys. Res., 119, doi:10.1002/ 2014JA020255, 2014.

50. Hamid, N. S. A., Huixin Liu, T. Uozumi, et al., Relationship between equatorial electrojet and global Sq currents at dip equator region, Earth. Planets and Space, 66:146, http://www.earth-planets-space.com/content/66/1/146, 2014.

51. Chen, H., Huixin Liu, T. Hanada, Storm-time atmospheric density modeling using neural networks and its application in orbit propagation, Adv. in Space. Res., 53, 558-567, doi:10.1016/j.asr.2013.11.052, 2014.

52. Guo, J., Huixin Liu, X. Feng, T. I. Pulkkinen, E. I. Tanskanen, C. Liu, D. Zhong, and Y. Wang, MLT and seasonal dependence of auroral electrojets: IMAGE magnetometer network observations, J. Geophys. Res., 119, doi:10.1002/2014JA019843, 2014.

53. Guo, J., T. I. Pulkkinen, E. I. Tanskanen, X. Feng, B. A. Emery, Huixin Liu, C. Liu, and D. Zhong, Annual variations in westward auroral electrojet and sub- storm occurrence rate during solar cycle 23, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019742, 2014.

54. Huixin Liu, H. Jin, Miyoshi, Y., H. Fujiwara, H, Shinagawa, Upper atmosphere response to stratosphere sudden warming: Local time and height dependence simulated by GAIA model, Geophys. Res. Lett., 40, 635-640, doi:10.1002/grl.50146, 2013a.

55. Huixin Liu, T. Hirano, S. Watanabe, Empirical model of the thermospheric mass density based on CHAMP satellite observations, J. Geophys. Res., 118, 843-848, doi:10.1002/jgra.50144, 2013b.

56. Shi, R. Huixin Liu, A. Yoshikawa, B. Zhang, B. Ni, Coupling of electrons and inertial Alfven waves in the topside ionosphere, J. Geophys. Res., 118, 1-8, doi:10.1002/jgra.50355, 2013.

57. Hamid, N. S. A., Huixin Liu, T. Uozumi, K. Yumoto, Equatorial electrojet dependence on solar activity in Southeast Asia sector, Antarctic Record, Vol.57, No.3, 329-337, 2013.

58. Hamid, N. S. A., Huixin Liu, T. Uozumi, K. Yumoto, Brief study of equatorial electrojet and global Sq currents at Southeast Asia region, Proceeding of the IEEE International Conference on Space Science and Communication, 194-197, 2013.

59. Yamazaki Y., A. D. Richmond, Huixin Liu, K. Yumoto, and Y. Tanaka, Sq current system during stratospheric sudden warming events in 2006 and 2009, J. Geophys. Res., 117, A12313, doi:10.1029/2012JA018116, 2012.

60. Tulasi Ram, S., N. Balan, B. Veenadhari, S. Gurubaran, S. Ravindran, T. Tsugawa, Huixin Liu, K. Niranjan, and T. Nagatsuma, First observational evidence for opposite zonal electric fields in equatorial E and F region altitudes during a geomagnetic storm period, J. Geophys. Res., 117, A09318, doi:10.1029/2012JA018045, 2012.

61. Miyoshi, Y., H. Jin, H. Fujiwara, H, Shinagawa, Huixin Liu, Wave-4 structure of the neutral density in the thermosphere and its relation to atmospheric tides, J. Atmos. Solar-Terres. Phys., Vol.90, 45-51, 2012.

62. Miyoshi, Y., H. Fujiwara, H. Jin, H, Shinagawa, Huixin Liu, Numerical simulation of the equatorial wind jet in the thermosphere, J. Geophys. Res., 117, A03309, doi:10.1029/2011JA017373, 2012.

63. Jusho M. H., K. Yumoto, N. S. Abdul Hamid, Huixin Liu, Electromagnetic Coupling on Solar-Terrestrial System: Possible effects on seismic activities, Proceedings of ISAP2012, 1160-1163, 2012.

64. Huixin Liu, M. Yamamoto, S. Tulasi Ram, T. Tsugawa, Y. Otsuka, C. Stolle, E. Doornbos, K. Yumoto, T. Nagatsuma, Equatorial Electrodynamics and Neutral Background in the Asian Sector During the 2009 Stratospheric Sudden Warming, J. Geophys. Res., 116, A08308, doi:10.1029/2011JA016607, 2011.

65. Huixin Liu, E. Doornbos, M. Yamamoto, S. T. Ram, Strong thermosphere cooling during the 2009 major statratosphere warming, Geophys. Res. Lett., 38, L12102, doi:10.1029/2011GL047898, 2011.

66. Huixin Liu, M. Yamamoto, Weakening of the mid-latitude summer night anomaly during geomagnetic storms, Earth. Planets and Space, 63, 371-375, doi:10.5047/eps.2010.11.012, 2011.

67. Tulasi Ram, S., M. Yamamoto, Huixin Liu, B. Veenadhari, S. Alex, Comment on “Westward electric field penetration to the dayside equatorial ionosphere during the main phase of the geomagnetic storm on 22 July 2009” by V. Sreeja et al., J. Geophys. Res., 116, A06315, doi:10.1029/2011JA016634, 2011.

68. Stolle, C., Huixin Liu, V. Trulik, H. Luehr, P. Richards, Solar flux variation of the electron temperature morning overshoot in the equatorial F region, J. Geophys. Res., 116, A04308, doi:10.1029/2010JA016235, 2011.

69. Kondo, T., A. Richmond, Huixin Liu, J. Lei, S. Watanabe, On the formation of a fast thermospheric zonal wind at the magnetic dip equator, Geophys. Res. Lett., 38, L10101, doi:10.1029/2011GL047255, 2011.

70. Lühr, H., Huixin Liu, J. Park, New aspects of the coupling between thermosphere and ionosphere, with special regards to CHAMP mission results, in "Aeronomy of the Earth's Atmosphere and Ionosphere", edited by Abdu, M. A., Pancheva, D., Springer, 303-316, 2011.

71. Lühr, H. J. Park, P. Ritter, Huixin Liu, In-situ CHAMP observations of the ionosphere-thermosphere coupling, Space Sci. Rev., doi:10.1007/s11214-011-9798-4, 2011.

72. Miyoshi, Y., H. Fujiwara, H. Jin, H, Shinagawa, Huixin Liu, K. Terada, Model study on the formation of the equatorial mass density anomaly in the thermosphere, J. Geophys. Res., 116, A05322, doi:10.1029/2010JA016315, 2011.

73. Balan, N., M. Yamamoto, J. Y. Liu, Y. Otsuka, Huixin Liu, H. Luhr, New aspects of thermospheric and ionospheric storms revealed by CHAMP, J. Geophys. Res., 116, A07305, doi:10.1029/2010JA016399, 2011.

74. Thampi, S. V., M. Yamamoto, C. Lin, Huixin Liu, Tomographic observations of the ionosphere over Japan during summer - Comparison with FORMOSAT3/COSMIC measurements, Radio. Sci., RS3001, doi:10.1029/2010RS004431, 2011.

75. Thampi, S. V., N. Balan, C. Lin, Huixin Liu, M. Yamamoto, Mid-latitude summer nighttime anomaly (MSNA) – observations and model simulations, Ann. Geophys., 29, 157-165, 2011.

76. Huixin Liu, S. V. Thampi, M. Yamamoto, Phase reversal of the diurnal cycle in the mid-latitude ionosphere, J. Geophys. Res., 115, A01305, doi:10.1029/2009JA014689, 2010.

77. Adachi, T., M. Yamaoka, M. Yamamoto, Y. Otsuka, Huixin Liu, C. Hsiao, A. Chen, R. Hsu, Midnight latitude-altitude distribution of 630-nm airglow in the Asian sector measured with Formosat-2/ISUAL, J. Geophys. Res., 115, A09315, doi:10.1029/2009JA015147, 2010.

78. Thampi, S. V., M. Yamamoto, Huixin Liu, S. Saito, Y. Otsuka, A. K. Patra, Nighttime-like Quasi Periodic echoes induced by a partial solar eclipse, Geophys. Res. Lett., 37, L09107, doi:10.1029/2010GL042855, 2010.

79. Thampi, S. V. , C. Lin, Huixin Liu, M. Yamamoto, First Tomographic Observations of the Mid-latitude Summer Nighttime Anomaly (MSNA) over Japan, J. Geophys. Res., 114, A10318, doi:10.1029/2009JA014439, 2009.

80. Huixin Liu, M. Yamamoto, H. Lühr, Wave-4 pattern of the equatorial mass density anomaly- A thermospheric signature of tropical deep convection, Geophys. Res. Lett., 36, L18104, doi:10.1029/2009GL039865, 2009.

81. Huixin Liu, H. Lühr, S. Watanabe, A solar terminator wave in thermospheric wind and density simultaneously observed by CHAMP, Geophys. Res. Lett., 36, L10109, doi:10.1029/2009GL038165, 2009.

82. Huixin Liu, S. Watanabe, T. Kondo, Fast thermospheric wind jet at the Earth's dip equator, Geophys. Res. Lett., 36, L08103, doi:10.1029/2009GL037377, 2009.

83. Huixin Liu, S. Watanabe, Seasonal variation in the longitudinal structure of the equatorial ionosphere: does it reflect tidal influences from below? J. Geophys. Res., 113, A08315, doi:10.1029/2008JA013027, 2008.

84. Forster, M., S. Rentz, W. Kohler, Huixin Liu, S. E. Haaland, IMF dependence of high-latitude thermospheric wind pattern derived from CHAMP cross-track measurements, Ann. Geophys., 26, 1581-1595, 2008.

85. Huixin Liu, C. Claudia, M. Forster, S. Watanabe, Solar activity dependence of the electron density at 400 km at equatorial and low latitudes observed by CHAMP, J. Geophys. Res., 112, A11311, doi:10.1029/2007JA012616, 2007.

86. Huixin Liu, H. Lühr, S. Watanabe, W. Koehler, C. Manoj, Contrasting behavior of the thermosphere and ionosphere to the Oct. 28, 2003 solar flare, J. Geophys. Res., 112, A07305, doi:10.1029/2007JA012313, 2007.

87. Huixin Liu, H. Lühr, S. Watanabe, Climatology of the Equatorial Thermospheric Mass Density Anomaly, J. Geophys. Res., 112, A05305, doi:10.1029/2006JA012199, 2007.

88. Lühr, H., S. Rentz, P. Ritter, Huixin Liu, K. Kausler, Averaged thermospheric wind patterns over polar regions, as observed by CHAMP, Ann. Geophys., 25, 1093–1101, 2007.

89. Huixin Liu, C. Stolle, S. Watanabe, T. Abe, D. Cooke, Evaluation of the IRI Model Using CHAMP Observations in Polar and Equatorial Regions, Adv. in Space. Res., 39, 904-909, 2007.

90. Soga, S., Huixin Liu, S. Watanabe, Y. Ogawa, Ion upflow observed in the polar region, Geophysical Bulletin of Hokkaido University, No. 70, 13-25, 2007.

91. Soga, S., Y. Ogawa, Huixin Liu, S. Watanabe, Observations of the ion upflow in the polar ionosphere, 21st JAXA atmospheric symposium, 109-112, 2007.

92. Lühr, H., Huixin Liu, Thermospheric response to magnetic storms, in "Solar Influence on the Heliosphere and Earth's Environment: Recent Progress and Prospects", edited by N. Gopalswamy and A. Bhattacharyya. ISBN: 81-87099-40-2, 369-375, 2006.

93. Huixin Liu, H. Lühr, Strong magnetic control of the Earth's thermosphere under both quiet and disturbed conditions, 20th JAXA atmospheric symposium, 106-110, 2006.

94. Huixin Liu, H. Lühr, S. Watanabe, V. Henize, W. Koehler, P. Visser, Zonal winds in the equatorial upper thermosphere: Decomposing the solar flux, geomagnetic activity, and seasonal dependencies, J. Geophys. Res., 111, A07307, doi:10.1029/2005JA011415, 2006.

95. Huixin Liu, H. Lühr, V. Henize, W. Köhler, Global distribution of the thermospheric total mass density derived from CHAMP, J. Geophys. Res., 110, A04301, doi:10.1029/2004JA010741, 2005.

96. Huixin Liu, H. Lühr, Strong disturbance of the upper thermospheric density due to magnetic storms: CHAMP observations, J. Geophys. Res., 110, A09S29, doi:10.1029/2004JA010908, 2005.

97. Huixin Liu, H. Lühr, W. Köhler, The enhancement of the thermospheric density during the Sept. 25-26, 2001 Magnetic Storm, in "Earth observation with CHAMP", edited by C. Reigber, H. Lühr, P. Schwintzer, J. Wickert, Springer, Berlin, 366-370, 2004.

98. Huixin Liu, Gang Lu, Velocity shear-related ion upflows in the low-altitude ionosphere, Ann. Geophysicae, 22, 1149-1153, 2004.

99. Ma, S.-Y., H.T. Cai, Huixin Liu, K. Schlegel, Positive storm effects in the dayside polar ionospheric F-region observed by EISCAT and ESR during the magnetic storm of the May 15, 1997, Ann. Geophysicae, 20, 1377-1384, 2002.

100.Ma, S.-Y., Huixin Liu, K. Schlegel, A comparative Study of Magnetic Storm Effects on the Ionosphere in Both Polar Cap and the Auroal Oval (1) - F-region Negative storm, Chinese Journal of Geophysics, 45, 156-165, 2002.

101.Huixin Liu, S.-Y. Ma, K. Schlegel, Diurnal, seasonal, and geomagnetic variations of large field-aligned ion upflows in the high-latitude ionospheric F region, J. Geophys. Res., 106, 24,651-24,662, 2001.

102. Ma, S.-Y., P. Liu, Huixin Liu, K. Schlegel, J.-S. Xu, A reversed plasma convection flow in the polar ionosphere observed with EISCAT radar, Chinese Journal of Geophysics, 44, 444-451, 2001.

103.Huixin Liu, K. Schlegel, S.-Y. Ma, Combined ESR and EISCAT observations of the dayside polar cap and auroral oval during the May 15, 1997 storm, Ann. Geophysicae, 18, 1067 - 1072, 2000.

104.Huixin Liu, S.-Y. Ma , K. Schlegel, Magnetic storm effects in the auroral ionosphere: two case studies, Wuhan University Journal of Natural Science, 5, 181 - 186, 1999.

105. Ma, S.-Y., Huixin Liu, K. Schlegel, J.-S. Xu, Storm-time Joule heating of auroral thermosphere and ionization depletion in the F-region - EISCAT radar observation, Chinese Journal of Space Science, 19, 34 - 41, 1999.

106.Huixin Liu, S.-Y. Ma, J. -S. Xu, Auroral ionospheric conductivity and energy flux of precipitating particles during magnetic storms, Annual Chinese Geophysical Society, 18, 255-257, 1998.

107.Ma, S.-Y., Huixin Liu, J.-S Xu, K. Schlegel, K. C. Yeh, Auroral thermosphere heating and electron density depletion in the F-region at high- and mid-latitudes during two intense magnetic storms, Ann. Geophysicae, 16, supplement, 845-845, 1998.

1. Huixin Liu, The upper atmosphere and space weather, Geoscience Research Center (GFZ), Potsdam, Germany, June, 2020.

2. Huixin Liu, The upper atmosphere response to external forcing, Polar Research Institute of China, Shanghai, China, August, 2019.

3. Huixin Liu, Vertical coupling in the Earth’s atmosphere, Lebniz Institute for Atmosphere Physics (IAP), Kuelungsborn, Germany, May, 2019.

4. Huixin Liu, Global distribution of Medium-scale gravity waves observed by GOCE, International Space Science Institute, Bern, Switzerland, March, 2019.

5. Huixin Liu, T. Yokoyama, Numerical simulation of neutral wind seeding of equatorial plasma bubbles, International Space Science Institute, Bern, Switzerland, March, 2019.

6. Huixin Liu, Medium-scale gravity waves its role in seeding equatorial plasma bubbles, National Center for Atmosphere Research, Boulder, USA, March, 2019.

7. Huixin Liu, Thermosphere and ionosphere response to solar flares, The 18th EISCAT symposium, Tokyo, Japan, May, 2017.

8. Huixin Liu, Thermosphere response to global warming: GAIA simulation results, Asia-Oceania Geophysical Society, Singapore, August, 2017.

9. Huixin Liu, Thermosphere interannual variability: potential fingerprints of QBO and ENSO, The 30th Atmosphere Symposium, JAXA/Kanegawa, December, Japan, 2016.

10. Huixin Liu, Thermosphere interannual variability: implications for ENSO and QBO, The International Whole Atmospherear Symposium, Tokyo, Japan, September, 2016.

11. Huixin Liu, Thermosphere interannual variability: ENSO effects, The Mesosphere-Thermosphere-ionosphere workshop, Tokyo, Japan, August, 2016.

12. Huixin Liu, Thermosphere and Ionosphere response to solar flares, VarSITI/ SCOSTEP symposium, Varna, Bulgaria, June, 2016.

13. Huixin Liu, Thermo sphere response to stratosphere sudden warming simulated by GAIA, ISEA14, Bahir Dar, Ethiopia, October, 2015.

14. H. Liu, Thermosphere response to external forcing: decadal observations from CHAMP, Mesosphere-Thermosphere-Ionosphere workshop, Tokyo, Japan, August, 2015.

15. Huixin Liu, Upper atmosphere response to stratosphere sudden warming events, SCOSTEP's 13th quadrennial solar-terrestrial physics symposium, Xian, China, October, 2014.

16. Huixin Liu, Vertical coupling in the atmosphere-ionosphere system in equatorial regions, CAWSESII workshop: Whole Atmosphere Coupling during solar cycle 24, Jhongli, Taiwan, July 14-17, 2013.

17. Huixin Liu, Empirical model of the thermospheric mass density based on CHAMP satellite observations, AOGS, Brisbane, Australia, June, 2013.

18. Huixin Liu, Vertical coupling in the Earth's equatorial atmosphere, SGEPSS fall meeting, Sapporo, Japan, November, 2012.

19. Huixin Liu, Upper atmosphere response to major and minor stratosphere sudden warming, ISEA13, Paracas, Peru, March 2012. (presented by M. Yamamoto due to schedule change)

20. Huixin Liu, Solar activity dependence of the thermosphere and ionosphere: contribution from 10 years of CHAMP observations, AGU fall meeting, San Francisco/USA, December, 2011.

21. Huixin Liu, Equatorial Electrodynamics and Neutral Background in the Asian sector during SSW2009, AOGS, Taipei, Taiwan, August, 2011.

22. Huixin Liu, Upper thermosphere coupling with the lower atmosphere: known and unknown, IUGG general assembly, Melbourne, Australia, June, 2011.

23. Huixin Liu, Vertical coupling in the Earth’s atmosphere and its implication for space operation, Japan Society for Aeronautical and Space Sciences (JAASS), Shizuoka/Japan, Nov. 17-19, 2010.

24. Huixin Liu, “Competition of ionospheric and lower atmospheric forcing on the thermosphere and its dimension dependence”, HAO seminar, National center for atmospheric research (NCAR), Boulder, USA, October, 2010.

25. Huixin Liu, “The Earth’s thermosphere and its response to external forcing”, GCOE seminar, Tohoku university, Japan, September, 2010.

26. Huixin Liu, Competition of the ionospheric and lower atmospheric forcing on the thermosphere and its dimension dependence, AP-RASC’10, Toyama, Japan, September, 2010.

27. Huixin Liu, “The Earth’s thermosphere-ionosphere system and its response to solar activities”, PRIC seminar, Polar research institute of China, Shanghai, China, August, 2010.

28. Huixin Liu, Phase reversal of the diurnal cycle in the mid-latitude ionosphere, COSPAR, Bremen, Germany, July, 2010.

29. Watanabe, S., Huixin Liu, T. Kondo, Ionosphere-thermosphere coupling in low latitude region, COSPAR, Bremen, Germany, July, 2010.

30. Huixin Liu, Wave-4 structure of the thermosphere, Japan Geophysical Union (JpGU), Makuhari, Japan, May, 2010.

31. Huixin Liu, Phase reversal of the diurnal cycle in the middle latitude ionosphere, International Reference Ionosphere (IRI) workshop, Kagoshima, Japan, November, 2009.

32. Stolle, C., Huixin Liu, Solar cycle variation of the electron temperature, International Reference Ionosphere (IRI) workshop, Kagoshima, Japan, November, 2009.

33. Huixin Liu, Fast wind jet at the Earth’s dip equator, AOGS, Singapore, August, 2009.

34. Watanabe, S., Huixin Liu, H. Luhr, Longitudinal distribution of electron density and temperature in ionospheric F-region, COSPAR, Canada, July, 2008.

35. Stolle, C., Huixin Liu, M. Forster, Climatological features of the ionosphere as derived from CHAMP observations and IRI predictions, COSPAR, Canada, July, 2008.

36. Huixin Liu, Strong Magnetic Control of the Thermospheric Density and Wind - an Updated View from CHAMP, Coupling Processes in the Equatorial Atomsphere (CPEA) international symposium, Kyoto, March, 2007.

37. Huixin Liu, S. Watanabe, H, Lühr, Climatology of the equatorial neutral wind observed by CHAMP, AOGS, Singapore, July, 2006.

38. Watanabe, S., Huixin Liu, T., Abe, et al., Ionosphere-thermosphere coupling in middle and low latitudes, AOGS, Singapore, July, 2006.

39. Lühr, H., Huixin Liu, Zonal winds in the thermosphere observed by CHAMP: diurnal variation and climatology, EGU, Wien, Austria, April, 2006.

40. Lühr, H., Huixin Liu, The thermospheric response to geomagnetic storms, International Living With a Star (ILWS) workshop, Goa, India, February 2006.

41. Lühr, H., Huixin Liu, Space Weather dependence of the air drag as observed by CHAMP, European Space Weather Week, ESA/ESTEC, November, 2005.

42. Huixin Liu, C. Stolle, M. Rotter, T. Abe, H. Lühr, S. Watanabe, Global distribution of the electron density and temperature in the F region observed by CHAMP, International Reference Ionosphere (IRI) workshop, Roquetes, Spain, June, 2005.