Empirical modeling of ionospheric F2 layer critical frequency over Wakkanai under geomagnetic quiet and disturbed conditions  

作　　者：LIU Jing LIU LiBo ZHAO BiQiang WAN WeiXing CHEN YiDing 

机构地区：[1]Beijing National Observatory of Space Environment,Institute of Geology and Geophysics,Chinese Academy of Sciences Beijing 100029,China [2]Graduate University of Chinese Academy of Sciences,Beijing 100049,China [3]State Key Laboratory of Space Weather,Center for Space Science and Applied Research,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Science China(Technological Sciences)》2012年第5期1169-1177,共9页中国科学（技术科学英文版）

基　　金：supported by the CMA (Grant No. GYHY201106011);the National Basic Research Program of China ("973" Project) (Grant No. 2012CB- 825604);the National Natural Science Foundation of China (Grant Nos. 41074112, 41174137, 41174138);the Specialized Research Fund for State Key Laboratories

摘　　要：The hourly values of the ionospheric F2 layer critical frequency, foF2, recorded at Wakkanai ionosonde station （45.4°N, 141.7°E） have been collected to construct a middle-latitude single-station model for forecasting foF2 under geomagnetic quiet and disturbed conditions. The module for the geomagnetic quiet conditions incorporates local time, seasonal, and solar vari- ability of climatological foF2 and its upper and lower quartiles. It is the first attempt to predict the upper and lower quartiles of foF2 to account for the notable day-to-day variability in ionospheric foF2. The validation statistically verifies that the model captures the climatological variations of foF2 with higher accuracy than IRI does. The storm-time module is built to capture the geomagnetic storm induced relative deviations of foF2 from the quiet time references. In the geomagnetically disturbed module, the storm-induced deviations are described by diumal and semidiumal waves, which are modulated by a modified magnetic activity index, the Kf index, reflecting the delayed responses of foF2 to geomagnetic activity forcing. The coeffi- cients of the model in each month are determined by fitting the model formula to the observation in a least-squares way. We provide two options for the geomagnetic disturbed module, including or not including Kalman filter algorithm. The Kalman filter algorithm is introduced to optimize these coefficients in real time. Our results demonstrate that the introduction of the Kalman filter algorithm in the storm time module is promising for improving the accuracy of predication. In addition, comparisons indicate that the IRI model prediction of the F2 layer can be improved to provide better performances over this region.

关 键 词：Empirical modeling Kalman f＇dter ionospheric storm 

分 类 号：P125.11[天文地球—天体测量] P318.5[天文地球—天文学]