Lunar tide in the equatorial electrojet in relation to stratospheric warmings

• Published in: Journal of Geophysical Research: Space Physics 2011-12, Vol.116 (A12), p.n/a
• Main Author: Stening, R. J.
• Format: Article
• Language: English
• Subjects: Atmospheric sciences; electrojet; lunar; magnetic variations; Moon; Stratosphere; stratospheric warmings; Winter
• ISSN: 0148-0227; 2169-9380; 2156-2202; 2169-9402
• DOI: 10.1029/2011JA017047

The relationship between sudden stratospheric warmings (SSWs) and large‐amplitude lunar tides in the equatorial electrojet (EEJ) is studied. Analysis of ground magnetometer data shows that the lunar tide in the EEJ is maximum during the northern winter season except in the Pacific Ocean region. Since SSWs are also a northern winter phenomenon, it is suggested that the relation between the large lunar tide in the EEJ and the SSW may possibly be coincidental. The lunar tide in the geomagnetic variations at Huancayo is anomalously large compared with other EEJ stations. An examination of geomagnetic variations at EEJ stations during SSW events shows that afternoon counter‐electrojets are frequently present at new moon and full moon, though the relationship is sometimes broken. The observation of large lunar EEJs when no SSW is present and of various different delay times suggests that other atmospheric processes are likely to be in play. Key Points Lunar tide in equatorial electrojet seen during stratospheric warmings Lunar effects also when no SSW in northern winter Northen winter maximum‐amplitude lunar tide in EEJ except in the Pacific region