The solar spectral irradiance (SSI) dataset is a key record for studying and understanding the energetics and radiation balance in Earth’s environment. Understanding the long-term variations of the SSI over timescales of the 11-year solar activity cycle and longer is critical for many Sun–Earth research topics. Satellite measurements of the SSI have been made since the 1970s, most of them in the ultraviolet, but recently also in the visible and near-infrared. A limiting factor for the accuracy of previous solar variability results is the uncertainties for the instrument degradation corrections, which need fairly large corrections relative to the amount of solar cycle variability at some wavelengths. The primary objective of this investigation has been to separate out solar cycle variability and any residual uncorrected instrumental trends in the SSI measurements from the Solar Radiation and Climate Experiment (SORCE) mission and the Thermosphere, Mesosphere, Ionosphere, Energetic, and Dynamics (TIMED) mission. A new technique called the Multiple Same-Irradiance-Level (MuSIL) analysis has been developed, which examines an SSI time series at different levels of solar activity to provide long-term trends in an SSI record, and the most common result is a downward trend that most likely stems from uncorrected instrument degradation. This technique has been applied to each wavelength in the SSI records from SORCE (2003 – present) and TIMED (2002 – present) to provide new solar cycle variability results between 27 nm and 1600 nm with a resolution of about 1 nm at most wavelengths. This technique, which was validated with the highly accurate total solar irradiance (TSI) record, has an estimated relative uncertainty of about 5% of the measured solar cycle variability. The MuSIL results are further validated with the comparison of the new solar cycle variability results from different solar cycles.

中文翻译：

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使用多重相同辐照度级 (MuSIL) 分析技术解耦太阳变化和仪器趋势

太阳光谱辐照度 (SSI) 数据集是研究和理解地球环境中能量和辐射平衡的关键记录。了解 SSI 在 11 年太阳活动周期和更长的时间尺度上的长期变化对于许多太阳-地球研究课题至关重要。自 1970 年代以来，SSI 的卫星测量就开始了，其中大部分是在紫外线中，但最近也在可见光和近红外中进行了测量。先前太阳变化结果准确性的一个限制因素是仪器退化校正的不确定性，这需要相对于某些波长的太阳周期变化量进行相当大的校正。这项调查的主要目标是从太阳辐射和气候实验 (SORCE) 任务以及热层、中间层、电离层、高能和动力学 (TIMED) 任务中分离出太阳周期变化和任何残余的未校正仪器趋势。使命。已经开发了一种称为多重相同辐照度水平 (MuSIL) 分析的新技术，该技术检查太阳活动不同水平的 SSI 时间序列，以提供 SSI 记录的长期趋势，最常见的结果是向下最有可能源于未经校正的仪器退化的趋势。该技术已应用于 SORCE（2003 年至今）和 TIMED（2002 年至今）的 SSI 记录中的每个波长，以提供 27 nm 和 1600 nm 之间的新太阳周期变化结果，大多数波长的分辨率约为 1 nm。该技术已通过高度准确的总太阳辐照度 (TSI) 记录进行验证，估计相对不确定性约为测量的太阳周期变化的 5%。通过比较来自不同太阳周期的新太阳周期变化结果，进一步验证了 MuSIL 结果。