Symmetric and asymmetric enhancement of polar rain

• Main Authors: Kazuo Makita, Ching-I Meng
• Format: Report
• Language: English
• Published: Takushoku University 1985
• Subjects: Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=1759; http://id.nii.ac.jp/1291/00001759/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=1759&item_no=1&attribute_id=18&file_no=1

From the examination of low-energy electron observed by DMSP-F2,-F3 and -F4 satellites and solar wind data obtained by ISEE-3 satellite, we found that there are two different kinds of polar rain intensification, which are characterized by symmetric and asymmetric enhancement in the two hemispheres, respectively. The intense uniform precipitation of polar rain observed over both hemispheres (symmetric enhancement of polar rain) generally occurs during the period of large IMF fluctuations. This type of precipitation seems to be related to the sudden storm commencement on the ground. On the other hand, the occurrence of intense polar rain observed in only one hemisphere (asymmetric enhancement of polar rain) depends on the polarity of the IMF Bx component. Namely, intense precipitation over the southern polar cap is mostly observed in the positive IMF Bx period. On the contrary, when IMF Bx is negative, intense precipitation can be seen in the northern polar cap.