两种静日曲线推算方法生成宇宙噪声吸收Keogram二维演化特征的比较研究  

A comparative study of the cosmic noise absorption Keograms generated by two different quiet day curve techniques

作　　者：何昉[1,2] 胡红桥[1] 杨惠根[1] 胡泽骏[1] 

机构地区：[1]中国极地研究中心,国家海洋局极地科学重点实验室,上海200136 [2]中国科学院地质与地球物理研究所,地球与行星物理重点实验室,北京100029

出　　处：《地球物理学报》2015年第1期1-11,共11页Chinese Journal of Geophysics

基　　金：国家自然科学基金青年项目(41104105);国家自然科学基金面上项目(41374159);南极环境综合考察与评估专项南极环境综合分析与评价专题(CHINARE-2015-04-01)资助

摘　　要：报导了2012年7月12—14日太阳活动期间,中国南极中山站成像式宇宙噪声接收机的观测结果.利用两种不同静日曲线推算方法对此次太阳活动事件中的宇宙噪声吸收进行了分析比较.结果表明,两种不同的静日曲线推算方法生成的Keogram总体呈现相似的变化特征,对强吸收区域上述两类Keogram都能得到一致的反映.但对于弱吸收区域而言,基于He等提出的静日曲线方法得到的Keogram能较好表现吸收区域轮廓并反映其空间变化特征.由于弱吸收区域往往是连接分立强吸收事件之间的通道,它的存在对于判定相邻的两次吸收事件是否相互关联以及吸收区域的运动速度至关重要,因此He等提出的静日曲线推算方法对于直观描述电离层对宇宙噪声吸收事件中的动态变化过程有更好的效果.Observation results of the Image Riometer at Zhongshan Station,Antarctica have been reported during the solar event on 12-14 th July,2012.In order to evaluate the performance of two quiet day curve（QDC）generation techniques,cosmic noise absorption Keograms were built and analyzed.Due to the existence of the ionosphere and the changes of electron density in the ionosphere with the solar zenith angle,it is commonly expected to find diurnal variations in the received cosmic noise level.The cosmic noise absorption level is calculated based on the two different QDCs for 8×8array.The data of zenith row and column are extracted to get Keograms in different directions.The differences between the Keograms are analyzed.These Keogram images revealed some irregularly distributed absorption regions along the analyzed periods in the figures generated by both QDC techniques.However,a visual comparativeanalysis showed that all these regions seemed to be more intensive by He′s techniques.The images indicated that He′s technique for determining QDC allows us to infer that there is a region with weaker absorption near the N5E8 beam which enhanced and then faded from 19∶23∶41UT to 19∶26∶30UT. However,the same phenomenon was not shown for that of Tanaka′s technique.The Keogram obtained from 18∶28 UT to 18∶32 UT show that there are two tiny weak absorption areas merging into one giant absorption region in northwest beams,while the evolution process is not clearly displayed in Tanaka′s sequence.By comparing the CNA results with the in situ aurora Keogram,we found that He′s technique is appeared to produce a better QDC which will result in a more consistent CNA Keogram with in situ aurora Keogram.The results showed that the similar variation trends could be found on both Keograms while intense absorption occurred,but in the weak absorption regions fine structures were better expressed on the Keograms generated by the QDC proposed by He et al.It was suggested that the QDC technique proposed by He et al.makes a

关 键 词：宇宙噪声 吸收 静日曲线 

分 类 号：P352[天文地球—空间物理学]