地磁平静期赤道电集流的建模研究  

Modeling of the equatorial electrojet during geomagnetic quiet periods

作　　者：文昕 周云良[1] 熊超[1] WEN Xin;ZHOU YunLiang;XIONG Chao(School of Electronic Information,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学电子信息学院,武汉430072

出　　处：《地球物理学报》2024年第7期2519-2527,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金(42174186)资助.

摘　　要：本文利用Swarm-A卫星从2013年11月到2023年2月近十年观测的赤道电集流(Equatorial Electrojet,EEJ)数据,挑选地磁活动平静时(Kp≤3)EEJ的峰值电流密度为研究对象,构建了一个以经度、地方时、季节、太阳辐射通量和月相为参数的EEJ经验模型.将模型计算的EEJ与上述建模所用的Swarm-A卫星实测的EEJ进行比较发现,两者的相关系数约为0.76,平均绝对误差(均方根误差)约为20.91(27.32)mA·m^(-1).该模型可较好地反映Swarm-A卫星从2013年11月到2023年2月观测到的EEJ典型特征,比如,EEJ的幅度随着太阳辐射通量的增加而增加;EEJ有明显的日变化特征,在正午出现峰值,日出附近常出现反向EEJ;EEJ随经度变化呈现显著的波状结构;EEJ的季节变化特征明显,二分季节附近出现峰值,二至季节附近出现谷值;月相对EEJ产生明显影响,正午的EEJ在新月和满月附近出现极大值.为了进一步检验上述建立的EEJ模型的性能,我们利用Swarm-B卫星2013年11月到2023年2月期间地磁平静条件下观测的EEJ数据,对上述模型进行了验证,结果表明本文所建立的EEJ模型能较好地重现Swarm-B卫星观测的EEJ变化.By utilizing the Equatorial Electrojet(EEJ)data observed by the Swarm-A satellite in the past decade from November 2013 to February 2023,an empirical model of EEJ is constructed.In this model the peak densities of EEJ for quiet geomagnetic activity(Kp≤3)are characterized as a function of longitude,local time,season,solar radiation flux and moon phase.By taking advantage of our model,we can obtain the EEJ value corresponding to the EEJ value observed by Swarm-A.Statistically the correlation coefficient between the EEJ values calculated by our model and measured by Swarm-A satellite is about 0.76,and the average absolute error(the root mean square error)between the aforementioned two dataset is about 20.91(27.32)mA·m^(-1).It is indicated that the model can characterize the typical features of the EEJ observed by Swarm-A during the period from November 2013 to February 2023.These typical features include:(1)The modeled EEJ increases with the increasing of solar radiation flux;(2)EEJ has an obvious diurnal variation,reaching the maximum value at noon and usually presenting westward EEJ around sunrise;(3)EEJ shows a prominent longitudinal wave-like pattern;(4)the EEJ exhibits an obvious dependence on season,achieving the crests during equinox seasons and valleys for solstice seasons;(5)EEJ near noon has a maximum value for the new moon and full moon periods.In order to further verify the performance of our model,we validated it by using the EEJ current density data observed by Swarm-B from November 2013 to February 2023.And the results show that the model can reproduce well the variation of EEJ observed by Swarm-B.

关 键 词：赤道电集流 Swarm星座 经验模型 

分 类 号：P353[天文地球—空间物理学]