Effects of various solar indices on accuracy of Earth’s thermospheric neutral density models  

作　　者：WANG HongBo1,2 & ZHAO ChangYin1 1 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China 

出　　处：《Science China(Physics,Mechanics & Astronomy)》2009年第7期1120-1128,共9页中国科学：物理学、力学、天文学（英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant No 10773033)

摘　　要：Four kinds of solar indices F10.7, E10.7, S10, Mg10 and four thermospheric neutral density models, i.e., CIRA72, DTM94, NRLMSISE00 and JB2006, are discussed. The CHAMP accelerometer data are used to calculate thermospheric total mass density. Based on the comparison of the model densities with CHAMP observations, the effects of various indices on the model accuracy are detected. It is found that under quiet and moderate solar conditions (F10.7<160), all of the models’ errors are reduced about 15% by using E10.7 instead of F10.7, while under active solar conditions (F10.7>200) the error’s standard deviation using E10.7 increases quickly and causes the models’ accuracy to fall down. With regard to S10, Mg10, their effects under quiet solar conditions are inconspicuous. If under active solar conditions, they can reduce the model error’s standard deviation by 5%-10%, implying that S10, Mg10 make the model error more stable. The JB2006 model, which was constructed by multi-solar-index (F10.7, S10, Mg10), is compared with DTM94 and NRLMSISE00 based on single-solar-index. It is found that JB2006’s accuracy is better than DTM94’s, and is close to NRLMSISE00 under the quiet solar condition. During the solar burst occurring on October 26, 2003, JB2006 has been in best agreement with CHAMP observations. All in all, the new indices may improve thermospheric density models’ accuracy under some special conditions. Concretely, E10.7 may reduce the average error of models and S10, Mg10 may prevent the error’s divergence.Four kinds of solar indices F 10.7, E 10.7, S 10, Mg 10 and four thermospheric neutral density models, i.e., CIRA72, DTM94, NRLMSISE00 and JB2006, are discussed. The CHAMP accelerometer data are used to calculate thermospheric total mass density. Based on the comparison of the model densities with CHAMP observations, the effects of various indices on the model accuracy are detected. It is found that under quiet and moderate solar conditions (F 10.7<160), all of the models’ errors are reduced about 15% by using E 10.7 instead of F 10.7, while under active solar conditions (F 10.7>200) the error’s standard deviation using E 10.7 increases quickly and causes the models’ accuracy to fall down. With regard to S 10, Mg 10, their effects under quiet solar conditions are inconspicuous. If under active solar conditions, they can reduce the model error’s standard deviation by 5%–10%, implying that S 10, Mg 10 make the model error more stable. The JB2006 model, which was constructed by multi-solar-index (F 10.7, S 10, Mg 10), is compared with DTM94 and NRLMSISE00 based on single-solar-index. It is found that JB2006’s accuracy is better than DTM94’s, and is close to NRLMSISE00 under the quiet solar condition. During the solar burst occurring on October 26, 2003, JB2006 has been in best agreement with CHAMP observations. All in all, the new indices may improve thermospheric density models’ accuracy under some special conditions. Concretely, E 10.7 may reduce the average error of models and S 10, Mg 10 may prevent the error’s divergence.

关 键 词：SOLAR RADIATION index CHAMP ACCELEROMETER data NEUTRALS density model 

分 类 号：P182[天文地球—天文学]