Accurate measurement and monitoring of ecosystem productivity play a pivotal role in comprehending the intricate dynamics of the Earth system, particularly in the light of anthropogenic forcing. Sun-induced chlorophyll fluorescence (SIF), serving as a proxy, has garnered attention for its potential to elucidate the dynamics of terrestrial productivity by the existence of its mechanistic link with photosynthesis. Nevertheless, physiological mechanisms that regulate the relationship between the dynamics of gross primary productivity (GPP) and SIF remain shrouded in mystery. To better accommodate the research community on GPP–SIF relation, our study attempts to offer potential results by integrating multi-source Earth observation SIF and in-situ eddy flux datasets at an ecosystem level in India. The results elucidate that the studied ecosystem consistently acted as a steady CO₂ sink over the observed period, displaying a prominent double-hump seasonality and a solid correlation with SIF. Notably, this correlation was synchronous with the daily transitions of GPP. The integration of multi-source carbon fluxes and SIF datasets demonstrated a strong agreement with the in-situ data, reinforcing the reliability of our results. Our redundancy analysis by threshold binning underscores the significant positive influence of vapour pressure deficit (VPD) and photosynthetically active radiation (PAR), critical factors driving GPP and SIF, across a spectrum of temporal scales, ranging from the transient fluctuations of a day to annual panoramas. In essence, our study advocates for the synergistic utilisation of diverse datasets to unravel the underlying processes governing the relationship between GPP and SIF at multiple temporal scales. Our results and analyses are poised to propel interdisciplinary research forward by introducing novel dimensions to the GPP–SIF relationship in the Indian subcontinent.

准确测量和监测生态系统生产力在理解地球系统复杂的动态方面发挥着关键作用，特别是在人为强迫的情况下。太阳诱导的叶绿素荧光（SIF）作为一种替代指标，因其与光合作用的机制联系而阐明陆地生产力动态的潜力而受到关注。然而，调节总初级生产力（GPP）动态和 SIF 之间关系的生理机制仍然笼罩在神秘之中。为了更好地适应 GPP-SIF 关系的研究界，我们的研究试图通过整合印度生态系统层面的多源地球观测 SIF 和原位涡流数据集来提供潜在的结果。结果表明，所研究的生态系统在观测期间始终充当稳定的CO ₂汇，表现出显着的双峰季节性以及与SIF 的紧密相关性。值得注意的是，这种相关性与 GPP 的每日变化同步。多源碳通量和 SIF 数据集的整合证明了与现场数据的强烈一致性，增强了我们结果的可靠性。我们通过阈值分箱进行的冗余分析强调了蒸汽压赤字（VPD）和光合有效辐射（PAR）的显着积极影响，这是驱动GPP和SIF的关键因素，跨越一系列时间尺度，从一天的瞬时波动到每年的波动全景图。本质上，我们的研究主张协同利用不同的数据集来揭示在多个时间尺度上控制 GPP 和 SIF 之间关系的基本过程。我们的研究结果和分析旨在通过引入印度次大陆 GPP-SIF 关系的新维度来推动跨学科研究的发展。