The study of solar irradiance variability is of great importance in heliophysics, Earth’s climate, and space weather applications. These studies require careful identifying, tracking and monitoring of features in the solar photosphere, chromosphere, and corona. Do coronal bright points contribute to the solar irradiance or its variability as input to the Earth atmosphere? We studied the variability of solar irradiance for a period of 10 years (May 2010 – June 2020) using the Large Yield Radiometer (LYRA), the Sun Watcher using APS and image Processing (SWAP) on board PROBA2, and the Atmospheric Imaging Assembly (AIA), and applied a linear model between the segmented features identified in the EUV images and the solar irradiance measured by LYRA. Based on EUV images from AIA, a spatial possibilistic clustering algorithm (SPoCA) is applied to identify coronal holes (CHs), and a morphological feature detection algorithm is applied to identify active regions (ARs), coronal bright points (BPs), and the quiet Sun (QS). The resulting segmentation maps were then applied on SWAP images, images of all AIA wavelengths, and parameters such as the intensity, fractional area, and contribution of ARs/CHs/BPs/QS features were computed and compared with LYRA irradiance measurements as a proxy for ultraviolet irradiation incident to the Earth atmosphere. We modeled the relation between the solar disk features (ARs, CHs, BPs, and QS) applied to EUV images against the solar irradiance as measured by LYRA and the F10.7 radio flux. A straightforward linear model was used and corresponding coefficients computed using a Bayesian method, indicating a strong influence of active regions to the EUV irradiance as measured at Earth’s atmosphere. It is concluded that the long- and short-term fluctuations of the active regions drive the EUV signal as measured at Earth’s atmosphere. A significant contribution from the bright points to the LYRA irradiance could not be found.

太阳辐照度变化的研究在太阳物理学、地球气候和空间天气应用中具有重要意义。这些研究需要仔细识别、跟踪和监测太阳光球、色球和日冕的特征。日冕亮点是否有助于太阳辐照度或其变化作为地球大气的输入？我们使用大产量辐射计 (LYRA)、使用 APS 和 PROBA2 上的图像处理 (SWAP) 的 Sun Watcher 以及大气成像组件 ( AIA），并在 EUV 图像中识别的分割特征和 LYRA 测量的太阳辐照度之间应用线性模型。基于 AIA 的 EUV 图像，应用空间可能性聚类算法（SPoCA）识别日冕洞（CH），应用形态特征检测算法识别活动区（AR）、日冕亮点（BP）和安静太阳（QS）。然后将得到的分割图应用于 SWAP 图像、所有 AIA 波长的图像，并计算强度、分数面积和 AR/CHs/BPs/QS 特征的贡献等参数，并与 LYRA 辐照度测量值进行比较，作为代表紫外线照射到地球大气层。我们模拟了应用于 EUV 图像的太阳盘特征（AR、CH、BP 和 QS）与由 LYRA 和 F10.7 无线电通量测量的太阳辐照度之间的关系。使用了一个简单的线性模型，并使用贝叶斯方法计算了相应的系数，表明活动区域对在地球大气中测量的 EUV 辐照度有很强的影响。得出的结论是，活动区域的长期和短期波动驱动了在地球大气层测量的 EUV 信号。没有发现亮点对 LYRA 辐照度的显着贡献。