Solar irradiance variability: a six-year comparison between SORCE observations and the SATIRE model
Solar irradiance variability: a six-year comparison between SORCE observations and the SATIRE model
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DOI：
10.1051/0004-6361/201016189
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发表时间：
2011-04
影响因子：
6.5
通讯作者：
W. Ball;Y. Unruh;N. Krivova;S. Solanki;J. Harder
中科院分区：
文献类型：
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作者：
W. Ball;Y. Unruh;N. Krivova;S. Solanki;J. Harder
目标。我们研究了模拟的太阳辐照度与SORCE卫星的测量结果的一致性，包括太阳总辐照度和在几年的时间尺度上分解成光谱区域。方法。我们使用了SATIRE模式，将2003年2月25日至2009年11月1日期间模拟的太阳总辐照度（TSI）与TSI测量值进行了比较。在2004年4月21日至2009年11月1日期间，与SORCE上的SIM仪器比较了200 - 1630 nm的光谱太阳辐照度。我们在~ 10 nm波段讨论了从中度活动到最近太阳极小期这段时间内通量的总体变化以及旋转和长期趋势，并讨论了三个重要的光谱区域：200 - 300 nm以上的紫外，400 - 691 nm以上的可见光和972 - 1630 nm之间的红外。结果。该模型捕获了观测到的97%的TSI变化。这是在所考虑的期间内TSI探测器彼此一致的顺序。在光谱比较中，旋转变异性得到了很好的再现，特别是在400和1200 nm之间。在几乎所有波长上，SIM的长期趋势变化幅度要大很多倍，而在500 - 700 nm之间和1000 - 1200 nm之间，SIM的趋势与可见的讽刺相反。我们讨论了SIM数据和模型的识别极限的剩余问题，特别是处理光斑贡献的方式，太阳极小期MDI磁图的通量识别极限以及讽刺所使用的IR模型大气。然而，这些领域的改善不太可能在长期趋势中显著加强协议。如果SIM数据正确的话，这种分歧意味着除了表面磁性之外的一些机制正在导致SSI的变化，特别是在2004年至2006年之间。由于SATIRE能够从UARS重现1991年至2002年之间的紫外线辐照度，要么是太阳SSI变化的机制在第23周期峰值附近发生了根本变化，要么是UARS和source紫外线测量值之间存在不一致。我们赞成第二种解释。
Aims. We investigate how well modeled solar irradiances agree with measurements from the SORCE satellite, both for total solar irradiance and broken down into spectral regions on timescales of several years. Methods. We use the SATIRE model and compare modeled total solar irradiance (TSI) with TSI measurements over the period 25 February 2003 to 1 November 2009. Spectral solar irradiance over 200−1630 nm is compared with the SIM instrument on SORCE over the period 21 April 2004 to 1 November 2009. We discuss the overall change in flux and the rotational and long-term trends during this period of decline from moderate activity to the recent solar minimum in ∼10 nm bands and for three spectral regions of significant interest: the UV integrated over 200−300 nm, the visible over 400−691 nm and the IR between 972−1630 nm. Results. The model captures 97% of the observed TSI variation. This is on the order at which TSI detectors agree with each other during the period considered. In the spectral comparison, rotational variability is well reproduced, especially between 400 and 1200 nm. The magnitude of change in the long-term trends is many times larger in SIM at almost all wavelengths while trends in SIM oppose SATIRE in the visible between 500 and 700 nm and again between 1000 and 1200 nm. We discuss the remaining issues with both SIM data and the identified limits of the model, particularly with the way facular contributions are dealt with, the limit of flux identification in MDI magnetograms during solar minimum and the model atmospheres in the IR employed by SATIRE. However, it is unlikely that improvements in these areas will significantly enhance the agreement in the long-term trends. This disagreement implies that some mechanism other than surface magnetism is causing SSI variations, in particular between 2004 and 2006, if the SIM data are correct. Since SATIRE was able to reproduce UV irradiance between 1991 and 2002 from UARS, either the solar mechanism for SSI variation fundamentally changed around the peak of cycle 23, or there is an inconsistency between UARS and SORCE UV measurements. We favour the second explanation.