Far-Ultraviolet Intensities and Center-to-Limb Variations of Active Regions and Quiet Sun Using UARS SOLSTICE Irradiance Measurements and Ground-based Spectroheliograms
Far-Ultraviolet Intensities and Center-to-Limb Variations of Active Regions and Quiet Sun Using UARS SOLSTICE Irradiance Measurements and Ground-based Spectroheliograms
复制标题
使用 UARS 至日辐照度测量和地面光谱日光图测量活动区域和安静太阳的远紫外线强度和中心到肢体的变化
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发表时间：
2001
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影响因子：
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通讯作者：
K. Bowman
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作者：
J. Worden;T. Woods;K. Bowman
通过最小化太阳-恒星辐照度比较实验（SOLSTICE）远紫外线（FUV）辐照度测量的时间序列和取决于太阳表面特征分布的太阳辐照度模型之间的方差，估计活动区域、增强网络（大规模活动区域碎片）和安静太阳的平均强度和中心到肢体的变化。该模型受到将广泛的太阳特征分组为四个组成部分的限制，这些组成部分对太阳活动周期中太阳辐照度的变化影响最大。这些成分的区域是通过使用尺寸、填充因子、强度和邻接性标准的算法在大约 800 张地面 Ca II K 光谱日照图上识别的。这 800 张地图是太阳辐照度模型的“已知”参数。该模型的未知参数是这四个分量的平均强度和中心到肢体的变化。由于与 SOLSTICE 测量和 Ca II K 图相关的系统不确定性，我们仅限于报告 120.0 和 170.0 nm 之间波长的活动区域、增强网络和安静太阳的计算强度和中心到肢体变化。我们发现活动区域中心到边缘的变化与基于图像的安静太阳中心到边缘变化的测量之间具有良好的光谱一致性。据报告，海滩、增强网络和安静太阳的强度典型不确定性约为 8%。这种不确定性主要与 SOLSTICE FUV 校准有关。
The average intensity and center-to-limb variation of active regions, enhanced network (large-scale active region fragments), and quiet Sun are estimated by minimizing the variance between time series of the Solar-Stellar Irradiance Comparison Experiment (SOLSTICE) far-ultraviolet (FUV) irradiance measurements and a model of the solar irradiance that depends on the distribution of solar surface features. The model is constrained by grouping the broad range of solar features into four components that contribute the most to solar irradiance variability over the solar activity cycle. The areas of these components arc identified on approximately 800 ground-based Ca II K spectroheliograms with an algorithm that uses criteria of size, filling factor, intensity, and contiguity. These 800 maps are the "known" parameters to the solar irradiance model. The unknown parameters to this model are the average intensities and center-to-limb variation of these four components. Because of systematic uncertainties associated with the SOLSTICE measurements and the Ca II K maps we are limited to reporting the computed intensities and center-to-limb variation of active regions, enhanced network, and quiet Sun for wavelengths between 120.0 and 170.0 nm. We find good spectral agreement between active region center-to-limb variations and image-based measurements of quiet-Sun center-to-limb variations. Intensities for plage, enhanced network, and quiet Sun are reported with a typical uncertainty of about 8%. This uncertainty is primarily associated with the SOLSTICE FUV calibration.