Abstract. Satellite-based solar-induced chlorophyll fluorescence (SIF) serves as a valuable proxy for monitoring the photosynthesis of vegetation globally. The Global Ozone Monitoring Experiment-2A (GOME-2A) SIF product has gained widespread popularity, particularly due to its extensive global coverage since 2007. However, serious temporal degradation of the GOME-2A instrument is a problem, and there is currently a lack of time-consistent GOME-2A SIF products that meet the needs of temporal trend analysis. In this paper, the GOME-2A instrument's temporal degradation was first calibrated using a pseudo-invariant method, which revealed 16.21 % degradation of the GOME-2A radiance at the near-infrared (NIR) band from 2007 to 2021. Based on the calibration results, the temporal degradation of the GOME-2A radiance spectra was successfully corrected by using a fitted quadratic polynomial function whose determination coefficient (R2) was 0.851. Next, a data-driven algorithm was applied for SIF retrieval at the 735–758 nm window. Also, a photosynthetically active radiation (PAR)-based upscaling model was employed to upscale the instantaneous clear-sky observations to monthly average values to compensate for the changes in cloud conditions and atmospheric scattering. Accordingly, a global temporally consistent GOME-2A SIF dataset (TCSIF) for 2007 to 2021 with the correction of temporal degradation was successfully generated, and the spatiotemporal pattern of global SIF was then investigated. Corresponding trend maps of the global temporally consistent GOME-2A SIF showed that 62.91 % of vegetated regions underwent an increase in SIF, and the global annual averaged SIF exhibited a trend of increasing by 0.70 % yr−1 during the 2007–2021 period. The TCSIF dataset is available at https://doi.org/10.5281/zenodo.8242928 (Zou et al., 2023).

中文翻译：

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TCSIF：时间一致的全球全球臭氧监测实验 2A (GOME-2A) 太阳诱导叶绿素荧光数据集，并校正了传感器退化


摘要。基于卫星的太阳诱导叶绿素荧光（SIF）是监测全球植被光合作用的重要指标。全球臭氧监测实验2A（GOME-2A）SIF产品受到广泛欢迎，特别是由于自2007年以来其广泛的全球覆盖范围。然而，GOME-2A仪器存在严重的时间退化问题，目前缺乏时间一致的GOME-2A SIF产品，满足时间趋势分析的需求。在本文中，首先使用伪不变方法对GOME-2A仪器的时间退化进行了校准，结果显示从2007年到2021年，GOME-2A在近红外（NIR）波段的辐射率退化了16.21%。结果，利用确定系数（R2）为0.851的拟合二次多项式函数成功校正了GOME-2A辐射光谱的时间退化。接下来，应用数据驱动算法在 735-758 nm 窗口进行 SIF 检索。此外，还采用基于光合有效辐射（PAR）的放大模型将瞬时晴空观测值放大到月平均值，以补偿云状况和大气散射的变化。据此，成功生成了2007年至2021年全球时间一致的GOME-2A SIF数据集（TCSIF），并进行了时间退化校正，然后研究了全球SIF的时空模式。全球时间一致的GOME-2A SIF对应的趋势图显示，62.91％的植被区域出现了SIF的增加，并且全球年平均SIF在2007-2021年期间呈现出增加0.70％ yr−1的趋势。 TCSIF 数据集可在 https://doi.org/10.5281/zenodo.8242928 上获取（Zou 等人，2023）。