Response of Vegetation Photosynthesis to the 2022 Drought in Yangtze River Basin by Diurnal Orbiting Carbon Observatory-2/3 Satellite Observations
Global warming has triggered a surge in severe drought worldwide, disrupting vegetation photosynthesis and profoundly altering the global carbon cycle. However, the immediate and time-lagged responses of vegetation photosynthesis to warming drought remain unclear. Most current research on regional-s...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Association for the Advancement of Science (AAAS)
2025-01-01
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| Series: | Journal of Remote Sensing |
| Online Access: | https://spj.science.org/doi/10.34133/remotesensing.0445 |
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| Summary: | Global warming has triggered a surge in severe drought worldwide, disrupting vegetation photosynthesis and profoundly altering the global carbon cycle. However, the immediate and time-lagged responses of vegetation photosynthesis to warming drought remain unclear. Most current research on regional-scale solar-induced chlorophyll fluorescence (SIF) drought stress relies on daily or even monthly datasets, limiting insights into the diurnal dynamics of photosynthesis under drought. To address these gaps, we developed a continuous hourly SIF dataset (HC-SIFOCO) based on observations from Orbiting Carbon Observatory-2 (OCO-2) and OCO-3. HC-SIFOCO exhibited accuracy comparable to that of tower-based observations in terms of diurnal photosynthesis [SIF: R2 ≥ 0.89, GPP (gross primary productivity): R2 ≥ 0.94]. Then, we used this dataset to investigate the drought in the Yangtze River Basin in 2022. According to our analysis, the initial signs of drought-induced stress are reflected in a decrease in vegetation fluorescence efficiency, followed by anomalies in SIF and, finally, abnormalities in canopy structure. Drought has led to an approximately 3% increase in midday depression compared to previous years while also causing an advancement in the seasonal peak. Furthermore, immediate decreases in atmospheric moisture were responsible for more than 70% of the decline in vegetation photosynthesis, with soil dryness playing a 2-month-later role. Although temperature generally benefited photosynthesis, this effect diminished dramatically at midday. In summary, we present a new method for obtaining high-resolution temporal SIF data, providing new insights into the vegetation’s diurnal response to drought. |
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| ISSN: | 2694-1589 |