Does the F10.7 index correctly describe solar EUV flux during the deep solar minimum of 2007-2009?
Does the F10.7 index correctly describe solar EUV flux during the deep solar minimum of 2007-2009?
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DOI：
10.1029/2010ja016301
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发表时间：
2011-04-08
影响因子：
2.8
通讯作者：
Wan, Weixing
中科院分区：
文献类型：
--
作者：
Chen, Yiding;Liu, Libo;Wan, Weixing
本文表明，在2007 - 2009年太阳活动极小期（Smin）期间，太阳极紫外（EUV）通量与F - 10.7指数之间的关系不同于之前的太阳活动极小期。这种差异在foF(2)与F - 10.7的关系中也有所体现。我们收集了截至2010年6月的太阳和太阳风层探测器（SOHO）/太阳 EUV监测仪（SEM）的EUV观测数据以及F - 10.7指数，以研究近期太阳活动极小期的太阳辐照度。我们发现，由于从上次太阳活动极小期到近期的这次，F - 10.7和太阳EUV通量下降幅度不同（EUV通量下降幅度更大），对于相同的F - 10.7，近期太阳活动极小期的EUV通量明显低于上次。也就是说，F - 10.7在近期太阳活动极小期中不像在上次那样能够描述太阳EUV辐照度。这在电离层foF(2)中引起了显著的响应。对于相同的F - 10.7，近期太阳活动极小期的foF(2)低于上次；而且，它也低于之前其他的太阳活动极小期。因此，在近期太阳活动极小期，F - 10.7不是foF(2)的理想指标，这意味着在此期间F - 10.7不是太阳EUV辐照度的理想替代指标，尽管它在之前的太阳活动极小期中是适用的。在太阳活动周期研究中，太阳辐照度模型和电离层模型需要考虑到这一点。
This paper shows that the relationship between solar EUV flux and the F-10.7 index during the extended solar minimum (Smin) of 2007-2009 is different from that in the previous Smin. This difference is also seen in the relationship between f(o)F(2) and F-10.7. We collected SOHO/SEM EUV observations and the F-10.7 index, through June 2010, to investigate solar irradiance in the recent Smin. We find that, owing to F-10.7 and solar EUV flux decreased from the last Smin to the recent one with different amplitudes (larger in EUV flux), EUV flux is significantly lower in the recent Smin than in the last one for the same F-10.7. Namely, F-10.7 does not describe solar EUV irradiance in the recent Smin as it did in the last Smin. That caused remarkable responses in ionospheric f(o)F(2). For the same F-10.7, f(o)F(2) in the recent Smin is lower than that in the last one; further, it is also lower than that in other previous Smins. Therefore, F-10.7 is not an ideal indicator of f(o)F(2) during the recent Smin, which implies that F-10.7 is not an ideal proxy for solar EUV irradiance during this period, although it has been adequate during previous Smins. Solar irradiance models and ionospheric models will need to take this into account for solar cycle investigations.