文章基本信息

标题：Polar cap ionosphere and thermosphere during the solar minimum period: EISCAT Svalbard radar observations and GCM simulations
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作者：Hitoshi Fujiwara ; Satonori Nozawa ; Sawako Maeda 等
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2012
卷号：64
期号：6
页码：459-465
DOI：10.5047/eps.2011.05.023
出版社：Springer Verlag
摘要：The IPY long-run data were obtained from the European Incoherent Scatter Svalbard radar (ESR) observations during March 2007 and February 2008.Since the solar and geomagnetic activities were quite low during the period, this data set is extremely helpful for describing the basic states (ground states) of the thermosphere and ionosphere in the polar cap region.The monthly-averaged ion temperatures for 12 months show similar local time (or UT) variations to each other.The ion temperatures also show significant seasonal variations.The amplitudes of the local time and seasonal variations observed are much larger than the ones predicted by the IRI-2007 model.In addition, we performed numerical simulations with a general circulation model (GCM), which covers all the atmospheric regions, to investigate variations of the neutrals in the polar thermosphere.The GCM simulations show significant variations of the neutral temperature in the polar region in comparison with the NRLMSISE-00 empirical model.These results indicate that both the ions and neutrals would show larger variations than those described by the empirical models, suggesting significant heat sources in the polar cap region even under solar minimum and geomagnetically quiet conditions.
关键词：Polar cap ;ionosphere ;thermosphere ;EISCAT radar ;GCM ;simulation ;IPY ;solar minimum