劇烈的太陽磁暴所造成之電離層擾動會影響人類活動及民生系統，如定位與導航、電力或高頻通訊系統等，因此要如何準確地預測電離層在磁暴時的狀態是目前重要的課題。本研究使用資料同化的技術發展一套太空天氣預報系統 — Data Assimilation Research Testbed / Thermosphere-Ionosphere-Electrodynamics General Circulation Model 2.0 (DART/TIE-GCM 2.0)，將全球地面GPS觀測之全電子含量運用系集卡爾曼濾波的方法 (由同化軟體DART執行) 同化至電離層物理模式TIE-GCM 2.0中，以重建2015年3月聖派翠克節磁暴的電子濃度三維結構與預報；再進一步於DART/TIE-GCM 2.0系統中結合Heelis、Weimer和AMIE三種不同的高緯度電位模式，並以方均根誤差以及方均根誤差百分比來評估這三個模式於此次磁暴事件，在低、中和高磁緯度地區的預報能力。研究發現造成此三個模式之電子濃度預報的差異不僅受高緯度能量輸入的影響，也和F層的緯向電場、F層傍晚的風場以及中性大氣組成，尤其是氧原子和氮分子的比值有重要的關聯。

The severe geomagnetic storm can prompt ionospheric plasma disturbances, affecting human activities and systems, such as positioning and navigation, electrical or HF communication systems. Therefore, accurately predicting the state of the ionosphere during magnetic storm is an important topic so far. This study attempts to reconstruct the three-dimensional structure and forecast of ionospheric electron density during the 2015 St. Patrick's Day magnetic storm by the data assimilation approach. Using the ensemble-based Kalman filter system named data assimilation research testbed (DART), the global ground-based GPS total electron content (TEC) observations are assimilated into the physical-base thermosphere‐ionosphere‐electrodynamics general circulation model 2.0 (TIE-GCM 2.0). The full system is called DART/TIE-GCM 2.0, and we further combine it with the three different high latitude potential models, Heelis, Weimer and AMIE models. The forecast capabilities of these three assimilation models during this storm event are evaluated by the root‐mean‐square error (RMSE) values and the RMSE ratio in different magnetic latitude regions. Results show that the differences of the ionospheric electron density forecasts among these three models are not only affected by the high-latitude energy input but also greatly depended on the zonal electric field in the F layer, the wind field in the F layer around dusk, and the neutral composition, especially O/N2 ratio.

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