A study on long-term trends of the ionosphere using observations at Chong-qing, China
A study on long-term trends of the ionosphere using observations at Chong-qing, China作者机构：National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave Propagation P. O. Box 6301 102206 Beijing China Department of Physics University of Tromsφ N-9037 Tromsφ Norway
出 版 物：《电波科学学报》 (Chinese Journal of Radio Science)
年 卷 期：2004年第19卷第Z1期
页 面：26-31,40页
核心收录：
学科分类：080904[工学-电磁场与微波技术] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学]
基 金：This work is supported by the National Natural Science Foundation of China with grants No. 49990455 and No. 40310223 and by the National key Laboratory of Electromagnetic Environment China Research Institute of Radiowave Propagation ( CRIRP )
主 题：sunspot number solar radio wavelet decomposition solar activities
摘 要：With long-term ionosonde records from 1947 to 2001 at Chong-qing, China, we show long-term trends of the ionospheric parameters, the critical frequencies of E-layer foE, F1-layer foF1 and F2-layer foF2, the E-layer height h E, and the F2-layer peak height hmF2, respectively. Using an approach of discrete wavelet decomposition arithmetic, we have got the long-term components in the variations of the iono spheric parameters. It does exist nearly linear long-term decreasing trends of above ionospheric parameters from 1947 to 1990, then a nearly linear increase from 1990 to 2001. The decreases are approximately by 0. 35MHz, 0. 4MHz, 2MHz,20km, respectively, for foE, foF1, foF2 and hmF2, but increase by 4km for h E,from 1947 to 1990. Simultaneously, we find similar long-term trends in the variations of 10.7cm solar radio flux and in sunspot number. The long-term components of the ionospheric parameters have extremely high correlation with those of 10.7cm solar radio flux and sunspot number. This implies that solar activities are the control factor of the long-term trends of the ionosphere. We confirm above conclusions with results from the long-term data at Slough station, UK.
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