ZHONG YunFang,
WANG Hui,
ZHENG ZhiChao et al
.2021.Seasonal and local time variations of auroral electrojet: CHAMP observation Chinese Journal of Geophysics(in Chinese),64(11): 3870-3881,doi: 10.6038/cjg2021O0459
极光电激流的地方时和季节变化特性研究:CHAMP卫星观测
仲云芳, 王慧, 郑志超, 何杨帆, 张科灯, 孙璐媛, 高洁
武汉大学电子信息学院空间物理系, 武汉 430072
Seasonal and local time variations of auroral electrojet: CHAMP observation
ZHONG YunFang, WANG Hui, ZHENG ZhiChao, HE YangFan, ZHANG KeDeng, SUN LuYuan, GAO Jie
Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan 430072, China
Abstract:The auroral electrojet is an important element of the polar current system. Based on ten years of high resolution scalar magnetic field data from CHAMP satellite, we studied the local time and seasonal variations of auroral electrojet. Furthermore, the auroral electrojet measured by satellite was compared with the auroral electrojet indices derived from the ground stations. It is shown that the daytime current is mainly controlled by the solar illumination, while the nighttime current is affected by the substorm. The auroral electrojet shows an obvious annual and semiannual variation. The eastward electrojet and the dayside westward electrojet are more intense in summer than in winter, while the nightside westward electrojet is more intense in winter than in summer. The eastward electrojet and the daytime westward electrojet is more intense at solstices, whereas the nighttime westward electrojet is more intense at equinoxes. The westward electrojet shows a good correlation with AL and SML indices. The eastward electrojet correlates well with the SMU index, but shows difference with the AU index. The discrepancy can be attributed to the fact that the peak eastward electrojet is located outside the detection range of the ground stations.
Ahn B H, Emery B A, Kroehl H W, et al. 1999. Climatological characteristics of the auroral ionosphere in terms of electric field and ionospheric conductance. Journal of Geophysical Research:Space Physics, 104(A5):10031-10040, doi:10.1029/1999JA900043. Akasofu S I, Perreault P D, Yasuhara F, et al. 1973. Auroral substorms and the interplanetary magnetic field. Journal of Geophysical Research, 78(31):7490-7508, doi:10.1029/JA078i031p07490. Baker D N, Pulkkinen T I, Angelopoulos V, et al. 1996. Neutral line model of substorms:Past results and present view. Journal of Geophysical Research:Space Physics, 101(A6):12975-13010, doi:10.1029/95JA03753. D'Onofrio M, Partamies N, Tanskanen E. 2014. Eastward electrojet enhancements during substorm activity. Journal of Atmospheric and Solar-Terrestrial Physics, 119:129-137, doi:10.1016/j.jastp.2014.07.007. Davis T N, Sugiura M. 1966. Auroral electrojet activity index AE and its universal time variations. Journal of Geophysical Research, 71(3):785-801, doi:10.1029/JZ071i003p00785. Guo J P, Pulkkinen T I, Tanskanen E I, et al. 2014a. Annual variations in westward auroral electrojet and substorm occurrence rate during solar cycle 23. Journal of Geophysical Research:Space Physics, 119(3):2061-2068, doi:10.1002/2013JA019742. Guo J P, Liu H X, Feng X S, et al. 2014b. MLT and seasonal dependence of auroral electrojets:IMAGE magnetometer network observations. Journal of Geophysical Research:Space Physics, 119(4):3179-3188, doi:10.1002/2014JA019843. Huang T, Lühr H, Wang H. 2017. Global characteristics of auroral Hall currents derived from the Swarm constellation:dependences on season and IMF orientation. Annales Geophysicae, 35(6):1249-1268, doi:10.5194/angeo-35-1249-2017. Kamide Y, Akasofu S I. 1976. The Auroral electrojet and field-aligned current. Planetary and Space Science, 24(3):203-213, doi:10.1016/0032-0633(76)90017-9. Kamide Y, Nakamura R. 1996. The convection electrojet and the substorm electrojet. Annales Geophysicae, 14(6):589-592, doi:10.1007/s00585-996-0589-2. Kamide Y, Kokubun S. 1996. Two-component auroral electrojet:Importance for substorm studies. Journal of Geophysical Research:Space Physics, 101(A6):13027-13046, doi:10.1029/96JA00142. Klimenko M V, Klimenko V V, Despirak I V, et al. 2018. Disturbances of the thermosphere-ionosphere-plasmasphere system and auroral electrojet at 30°E longitude during the St. Patrick's Day geomagnetic storm on 17-23 March 2015. Journal of Atmospheric and Solar-Terrestrial Physics, 180:78-92, doi:10.1016/j.jastp.2017.12.017. Liou K, Newell P T, Sibeck D G, et al. 2001. Observation of IMF and seasonal effects in the location of auroral substorm onset. Journal of Geophysical Research:Space Physics, 106(A4):5799-5810, doi:10.1029/2000JA003001. Lui A T Y, Akasofu S I, Hones E W, et al. 1976. Observation of the plasma sheet during a contracted oval substorm in a prolonged quiet period. Journal of Geophysical Research, 81(7):1415-1419, doi:10.1029/JA081i007p01415. Lui A T Y. 1996. Current disruption in the Earth's magnetosphere:Observations and models. Journal of Geophysical Research:Space Physics, 101(A6):13067-13088, doi:10.1029/96JA00079. Lyatsky W, Newell P T, Hamza A. 2001. Solar illumination as cause of the equinoctial preference for geomagnetic activity. Geophysical Research Letters, 28(12):2353-2356, doi:10.1029/2000GL012803. McPherron R L, Baker D N, Pulkkinen T I, et al. 2013. Changes in solar wind-magnetosphere coupling with solar cycle, season, and time relative to stream interfaces. Journal of Atmospheric and Solar-Terrestrial Physics, 99:1-13, doi:10.1016/j.jastp.2012.09.003. Newell P T, Meng C I, Lyons K M. 1996. Suppression of discrete aurorae by sunlight. Nature, 381(6585):766-767, doi:10.1038/381766a0. Newell P T, Sotirelis T, Skura J P, et al. 2002. Ultraviolet insolation drives seasonal and diurnal space weather variations. Journal of Geophysical Research:Space Physics, 107(A10):1305, doi:10.1029/2001JA000296. Newell P T, Sotirelis T, Wing S. 2010. Seasonal variations in diffuse, monoenergetic, and broadband aurora. Journal of Geophysical Research:Space Physics, 115(A3):A03216, doi:10.1029/2009JA014805. Newell P T, Gjerloev J W. 2011. Evaluation of SuperMAG auroral electrojet indices as indicators of substorms and auroral power. Journal of Geophysical Research:Space Physics, 116(A12):A12211, doi:10.1029/2011JA016779. Nishida A. 1968. Geomagnetic Dp 2 fluctuations and associated magnetospheric phenomena. Journal of Geophysical Research, 73(5):1795-1803, doi:10.1029/JA073i005p01795. Ohtani S, Gjerloev J W, Johnsen M G, et al. 2019. Solar illumination dependence of the auroral electrojet intensity:Interplay between the solar zenith angle and dipole tilt. Journal of Geophysical Research:Space Physics, 124(8):6636-6653, doi:10.1029/2019JA026707. Olsen N. 1996. A new tool for determining ionospheric currents from magnetic satellite data. Geophysical Research Letters, 23(24):3635-3638, doi:10.1029/96GL02896. Pulkkinen T I, Tanskanen E I, Viljanen A, et al. 2011. Auroral electrojets during deep solar minimum at the end of solar cycle 23. Journal of Geophysical Research:Space Physics, 116(A4):A04207, doi:10.1029/2010JA016098. Reigber C, Lühr H, Schwintzer P. 2002. CHAMP mission status. Advances in Space Research, 30(2):129-134, doi:10.1016/S0273-1177(02)00276-4. Ritter P, Lühr H, Viljanen A, et al. 2004. Ionospheric currents estimated simultaneously from CHAMP satellite and IMAGE ground-based magnetic field measurements:a statistical study at auroral latitudes. Annales Geophysicae, 22(2):417-430, doi:10.5194/angeo-22-417-2004. Russell C T, McPherron R L. 1973. Semiannual variation of geomagnetic activity. Journal of Geophysical Research, 78(1):92-108, doi:10.1029/JA078i001p00092. Shue J H, Kamide Y. 2001. Effects of solar wind density on auroral electrojets. Geophysical Research Letters, 28(11):2181-2184, doi:10.1029/2000GL012858. Shue J H, Kamide Y. 2006. Reduction in the westward auroral electrojet by a southward turning of the interplanetary magnetic field:A new interpretation. Geophysical Research Letters, 33(22):L22105, doi:10.1029/2006GL028091. Singh A K, Rawat R, Pathan B M. 2013. On the UT and seasonal variations of the standard and SuperMAG auroral electrojet indices. Journal of Geophysical Research:Space Physics, 118(8):5059-5067, doi:10.1002/jgra.50488. Wang H, Lühr H, Ma S Y. 2005a. Solar zenith angle and merging electric field control of field-aligned currents:A statistical study of the Southern Hemisphere. Journal of Geophysical Research:Space Physics, 110(A3):A03306, doi:10.1029/2004JA010530. Wang H, Lühr H, Ma S Y, et al. 2005b. Statistical study of the substorm onset:its dependence on solar wind parameters and solar illumination. Annales Geophysicae, 23(6):2069-2079, doi:10.5194/angeo-23-2069-2005 Wang H, Lühr H, Ridley A, et al. 2008. Storm time dynamics of auroral electrojets:CHAMP observation and the space weather modeling framework comparison. Annales Geophysicae, 26(3):555-570, doi:10.5194/angeo-26-555-2008. Wu Q, Rosenberg T J, Lanzerotti L J, et al. 1991. Seasonal and diurnal variations of the latitude of the westward auroral electrojet in the nightside polar cap. Journal of Geophysical Research:Space Physics, 96(A2):1409-1419, doi:10.1029/90JA02379. Xu W Y. 2009. Variations of the auroral electrojet belt during substorms. Chinese Journal of Geophysics (in Chinese), 52(3):607-615. Zhang J, Wang H, Zhang K D, et al. 2017. Statistical study of longitudinal variations of Hall currents at high latitudes:CHAMP observation. Chinese Journal of Geophysics (in Chinese), 60(10):3707-3717, doi:10.6038/cjg20171002. 附中文参考文献 徐文耀. 2009. 亚暴期间极光电集流带的变化. 地球物理学报, 52(3):607-615. 张静, 王慧, 张科灯等. 2017. 极区Hall电流经度差异特征的统计学研究:CHAMP卫星观测. 地球物理学报, 60(10):3707-3717, doi:10.6038/cjg20171002.