电离层对共转相互作用区（CIR）的全球响应特征分析及区域建模研究

The investigation and modeling of ionospheric response to geomagnetic activity is very important to satisfy the needs of ionospheric weather prediction. There are some previous primary results about ionospheric variations during the recurrent geomagnetic activity. In this project, the global ionospheric response to CIR-induced geomagnetic activity are planned to be studied in depth by using the global ionospheric observation, geomagnetic activity indicies, solar wind speed and interplanetary magnetic field measurements. In different latitudes and different local time, the delay time between CIR-induced geomagnetic activity and ionospheric disturbance will be analyzed, and the duration, the magnitude of ionospheric storm as well. The difference of ionospheric effects during CMEs and CIRs will also be investigated. The measurement of plasma drift and neutral component will be used to interpret ionosphere characteristic during CIR-induced geomagnetic activities. The theoretical model, like TIEGCM, is also used to help interpret ionospheric effect in different latitudes and different time periods. The last task of this project is to establish an empirical model to predict ionospheric variation during a CIR event at Chinese middle to low latitude. The modeling research will be useful to improve the ability of ionospheric forecasting in space weather operations.

了解电离层对地磁活动响应的全球特征并能进行模式化预报，是当前满足不断增长的电离层天气预报需求的一个重要方面。本项目拟在前期对重现性地磁暴引起的电离层响应研究的基础上，利用全球电离层、太阳风、地磁指数等观测资料，全面深入分析行星际共转相互作用区（CIR）引发地磁暴期间全球电离层的扰动特征，分不同地方时、不同经纬度分析CIR期间电离层扰动的延迟时间、扰动形态、强度和持续时间。进一步分析不同行星际源（CME和CIR）引发地磁暴期间电离层扰动特征的异同。并利用卫星中性成分和电场观测数据，配合成熟的理论模式，并加强对电离层暴时扰动新理论的调研，研究CIR期间控制不同时空范围内电离层扰动的物理机制。最后，综合考虑电离层扰动的特征和物理控制因子，建立我国中低纬地区电离层对CIR响应的预报模式，为在空间天气业务预报中提高电离层预报的准确性奠定基础。

本项目主要开展了日冕物质抛射（CME）和共转相互作用区（CIR）引起的磁暴期间电离层扰动特征的比较分析,明确了电离层暴在CME和CIR磁暴期间的延迟时间和持续时间有明显的不同，提出了根据磁暴源头的性质来判断电离层可能响应的新思路。并利用观测和模拟,进一步分析了CIR引起电离层暴特征的变化原因,对不同纬度不同响应特征进行了合理解释,特别是解释了中性成份增加可能是CIR期间低纬电子密度多天正暴的原因｡项目在电离层暴时特征参数提取和扰动信息提取方面也开展了研究，进一步采用当前先进的机器学习方法，建立了中国区域电离层TEC预报模式，评估表明模式平均误差在平静和暴时小于6TECU，处于当前国际电离层预报的先进水平，可进一步转化在具体的系统中提前24小时提供电离层修正和影响的信息，具有重要的应用价值。