Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.
Department of Landscape Architecture and Rural Systems Engineering, College of Agriculture and Life Sciences, Seoul National University, South Korea.
Sci Adv. 2023 Aug 2;9(31):eadi0775. doi: 10.1126/sciadv.adi0775.
Emerging new-generation geostationary satellites have broadened the scope for studying the diurnal cycle of ecosystem functions. We exploit observations from the Geostationary Operational Environmental Satellite-R series to examine the effect of a severe U.S. heatwave in 2020 on the diurnal variations of ecosystem photosynthesis. We find divergent responses of photosynthesis to the heatwave across vegetation types and aridity gradients, with drylands exhibiting widespread midday and afternoon depression in photosynthesis. The diurnal centroid and peak time of dryland gross primary production (GPP) substantially shift toward earlier morning times, reflecting notable water and heat stress. Our geostationary satellite-based method outperforms traditional radiation-based upscaling methods from polar-orbiting satellite snapshots in estimating daily GPP and GPP loss during heatwaves. These findings underscore the potential of geostationary satellites for diurnal photosynthesis monitoring and highlight the necessity to consider the increased diurnal asymmetry in GPP under stress when evaluating carbon-climate interactions.
新兴的新一代地球静止卫星拓宽了研究生态系统功能日变化的范围。我们利用地球静止业务环境卫星-R 系列的观测数据，研究了 2020 年美国严重热浪对生态系统光合作用日变化的影响。我们发现，光合作用对热浪的反应在植被类型和干旱梯度上存在差异，干旱地区的光合作用在中午和下午普遍出现下降。旱地总初级生产力（GPP）的日重心和峰值时间大幅提前到清晨，反映出明显的水热胁迫。我们基于地球静止卫星的方法在估计热浪期间的日 GPP 和 GPP 损失方面，优于传统基于极轨卫星快照的辐射扩展方法。这些发现突出了地球静止卫星在日变化光合作用监测方面的潜力，并强调在评估碳-气候相互作用时，有必要考虑在胁迫下 GPP 增加的日不对称性。
