Publication Date:
2016-07-29
Description:
We identify interplanetary plasma regions associated with three intense Interplanetary CMEs (ICMEs)-driven geomagnetic storm intervals which occurred around the same time of the year: DOY 74 – 79 March, of 2012, 2013 and 2015. We show that differences in solar wind drivers lead to different dynamical ionosphere-thermosphere (IT) responses and to different preconditioning of the IT system. We introduce a new hourly-based global metric for average low-latitude and northern middle-latitude Vertical Total Electron Content (VTEC) responses in the morning, afternoon and evening local time ranges, derived from measurements from globally distributed Global Navigation Satellite System (GNSS) ground stations. Our novel technique of estimating nitric oxide (NO) cooling radiation in 11° latitudinal zones is based on TIMED/SABER measurements. The thermospheric cooling throughout the storm phases is studied with this high latitudinal resolution for the first time. Additionally, TIMED/GUVI observations of the dynamical response of the thermospheric composition (O/N2 ratio) are utilized to study negative ionospheric storm effects. Based on these datasets we describe and quantify distinct IT responses to driving by ICME sheaths, magnetic clouds, coronal loop remnants, plasma discontinuities and high-speed streams following ICMEs. Our analysis of coupling functions indicates strong connection between coupling with the solar wind and IT system response in ICME-type storms and also some differences. Knowledge of interplanetary features is crucial for understanding IT storm dynamics.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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