The extremely intense CNA events observed at Zhongshan Station in July, 2000

• Main Authors: Hongqiao, Hu, Ruiyuan, Liu, Yonghua, Liu, Shunlin, Liu, Huigen, Yang, Zhonghua, Xu, Sato, Natuo, Yamagishi, Hisao
• Format: Article in Journal/Newspaper
• Language: English
• Published: Polar Research Institute of China - PRIC 2002
• Subjects: Zhongshan; Zhongshan Station; Advances in Polar Science; Antarc*; Antarctica; Polar Science
• Online Access: http://library.arcticportal.org/2229/; http://library.arcticportal.org/2229/1/200201002.pdf

Using the ground observation data at Zhongshan Station of Antarctica during July 13 to 17, 2000, the intense absorption events associated with the activities of the solar active region R9077 are analyzed. It was shown that an intense polar cap absorption event lasted more than 3 days, which was caused by the solar proton event associated with the X5/3B major flare at 1024 UT on July 17, with a typical day-night variation. At the same time, the intense solar activities extremely disturbed the magnetosphere, therefore aurora substorms occurred frequently. The energetic particle precipitation from the magnetosphere caused several absorption spikes superposing on the background of polar cap absorption. One distinct event is the absorption enhancement that started at about 0300 UT on July 15, reached its peak of 26dB at about 0645 UT and recovered at about 1110 UT on the same day, which was the strongest absorption event observed at Zhongshan Station since the imaging riometer installed in February, 1997. Another outstanding absorption spike with pulsation occurred at about 1753 UT on 14th, its peak reached to 6 dB.