An understanding of solar variability over a broad spectral range and broad range of timescales is needed by scientists studying Earth’s climate. The Total and Spectral Solar Irradiance Sensor (TSIS) Spectral Irradiance Monitor (SIM), is designed to measure solar spectral irradiance (SSI) with unprecedented accuracy from 200 nm to 2400 nm. SIM started daily observations in March 2018. To maintain its accuracy over the course of its anticipated 5-year mission and beyond, TSIS SIM needs to be corrected for optical degradation, common for solar viewing instruments. The differing long-term trends of various independent solar-irradiance records attest to the challenge at hand. The correction of TSIS SIM for optical degradation is based on piecewise linear fits that bring the three instrument channels into agreement. It is fundamentally different to the correction applied to the TSIS SIM predecessor on SORCE. The correction facilitates reproducibility, uncertainty estimation and is measurement-based. Corrected, integrated TSIS SIM SSI agrees with independent observations of total solar irradiance to within 45 ppm as well as various solar-irradiance models. TSIS SIM SSI is available at: http://lasp.colorado.edu/lisird/ .

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TSIS SIM 的退化校正

研究地球气候的科学家需要在广泛的光谱范围和广泛的时间尺度上了解太阳变化。总和光谱太阳辐照度传感器 (TSIS) 光谱辐照度监测器 (SIM) 旨在以前所未有的精度测量 200 nm 至 2400 nm 的太阳光谱辐照度 (SSI)。SIM 于 2018 年 3 月开始每日观测。为了在其预期的 5 年及以后的任务过程中保持其准确性，TSIS SIM 需要针对光学退化进行校正，这在太阳观测仪器中很常见。各种独立太阳辐照度记录的不同长期趋势证明了眼前的挑战。TSIS SIM 的光学退化校正基于分段线性拟合，使三个仪器通道一致。它与应用于 SORCE 上 TSIS SIM 前身的校正有根本的不同。校正有利于再现性、不确定性估计并且是基于测量的。更正、集成的 TSIS SIM SSI 与对 45 ppm 以内的总太阳辐照度的独立观测以及各种太阳辐照度模型一致。TSIS SIM SSI 可从以下网址获得：http://lasp.colorado.edu/lisird/。