电离层中纬槽极小的位置变化及其控制因素研究

本文利用2000年至2009年CHAMP卫星朗缪尔探针实地测量的电子密度数据,分析了电离层中纬槽的位置变化及其控制因素.研究结果表明: (1) 地磁平静期电离层中纬槽的位置随磁地方时和经度变化; (2) 电离层中纬槽的位置对地理经度的依赖表现为西半球槽的位置高于东半球; (3) AE指数和SYM-H指数与槽的位置变化显著相关,表明极光电集流和环电流是中纬槽位置变化的重要控制因素; (4) 太阳风电场晨-昏分量的量值变化显著影响中纬槽位置,而其极性变化的影响相对较弱.研究结果对中纬槽建模有一定的参考价值.

A study on the position variation of mid-latitude ionospheric trough minimum and its controlling factors

Based on in-situ electron density measurements from CHAMP Planar Langmuir Probe (PLP), the position variation of mid-latitude ionospheric trough (MIT) minimum and its controlling factors is investigated. The CHAMP PLP data were collected from 2000 to 2009. The gradient of electron density was used to recognize the MIT structure. Then the method of statistical analysis was used to investigate the dependence of the position of MIT minimum to the magnetic local time and geographic longitude during geomagnetic quiet time. And then the relations of the MIT minimum position with geomagnetic indexes and solar wind parameters are analyzed respectively.The results show that: (1) In the geomagnetic quiet period, the position of the trough minimum primarily varies with magnetic local time and geographic longitude. (2) The geographic longitude dependence of the trough minimum position shows that the latitudes of the MIT in the western hemisphere are higher than those in the eastern hemisphere as a whole. (3) The position variation of the MIT has significant correlations with SYM-H and AE, which indicates that SYM-H and AE are important controlling factors of the trough position. (4) The magnitude of dawn-dark component of solar wind electric field can significantly influence the position of the trough, but the influence of its polarity is relatively weaker. The magnetic local time and geomagnetic activity were regarded as the mainly factors controlling the movement of MIT. However, this paper indicates that the geographic longitude and the magnitude of dawn-dark component of solar wind electric field can also significantly influence the position of MIT. These factors should be considered in both theoretical and modeling researches in the future.