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Seasonal Variations of Solar-Induced Fluorescence, Precipitation, and Carbon Dioxide Over the Amazon

Albright, Ronald and Corbett, Abigail and Jiang, Xun and Creecy, Ellen and Newman, Sally and Li, King-Fai and Liang, Mao-Chang and Yung, Yuk L. (2022) Seasonal Variations of Solar-Induced Fluorescence, Precipitation, and Carbon Dioxide Over the Amazon. Earth and Space Science, 9 (1). Art. No. e2021EA002078. ISSN 2333-5084. doi:10.1029/2021ea002078.

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Previous studies suggested that the Amazon, the largest rainforest on Earth, changes from a CO₂ sink to a CO₂ source during the dry/fire season. However, the biospheric contributions to atmospheric CO₂ are not well understood during the two main seasons, the dry/fire season and the wet season. In this article, we utilize Orbiting Carbon Observatory 2 (OCO-2) Solar-Induced Fluorescence (SIF) to explore photosynthetic activity during the different seasons. The spatiotemporal variability of OCO-2 SIF, OCO-2 CO₂, precipitation, and burned area are investigated over the Amazon from September 2014 to December 2019. Averaging over the entire Amazon region, we found a positive temporal correlation (0.94) between OCO-2 SIF and Global Precipitation Climatology Project precipitation and a negative temporal correlation (−0.64) between OCO-2 SIF and OCO-2 CO₂, consistent with the fact that precipitation enhances photosynthesis, which results in higher values for SIF and rate of removal of CO₂ from the atmosphere above the Amazon region. We also observed seasonality in the spatial variability of these variables within the Amazon region. During the dry/fire (August–October) season, low SIF values, low precipitation, high vapor pressure deficit (VPD), large burned areas, and high atmospheric CO₂ are mainly found over the southern Amazon region. In contrast, during the wet season (January–March), high SIF values, high precipitation, low VPD, smaller burned areas, and low CO₂ are found over both the central and southern Amazon regions. The seasonal difference in SIF suggests that photosynthetic activity is reduced during the dry/fire season relative to the wet season as a result of low precipitation and high VPD, especially over the southern Amazon region, which will contribute to more CO₂ in the atmosphere during the dry/fire season.

Item Type:Article
Related URLs:
URLURL TypeDescription ItemGPCP Version 2.3 precipitation data ItemOCO-2 Version 10 SIF and column CO₂ data ItemMODIS burned area data ItemUser's manual
Jiang, Xun0000-0001-8932-3807
Creecy, Ellen0000-0003-4525-2896
Newman, Sally0000-0003-0710-995X
Li, King-Fai0000-0003-0150-2910
Liang, Mao-Chang0000-0002-5294-9344
Yung, Yuk L.0000-0002-4263-2562
Additional Information:© 2021 The Authors. Earth and Space Science published by Wiley Periodicals LLC on behalf of American Geophysical Union. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Issue Online: 18 January 2022; Version of Record online: 18 January 2022; Accepted manuscript online: 09 December 2021; Manuscript accepted: 24 November 2021; Manuscript revised: 20 November 2021; Manuscript received: 12 October 2021. The authors thank two anonymous referees and the editor for their time and constructive suggestions. The authors thank Dr. L. Li and Dr. H. Ajami for their help to this article. X. Jiang is supported by NASA ROSES NNH15ZDA001N-PDART Program. Y. L. Yung is supported by the NASA Science Team for the OCO-2 Mission. K.-F. Li is partially supported by NASA JPL Subcontracts 1631379 and 1653138. M.-C. Liang is supported by Ministry of Science and Technology, Taiwan (Grant 108-2111-M-001-011-MY3) and Academia Sinica (Grant AS-IA-109-M03). Data Availability Statement: GPCP Version 2.3 precipitation data can be downloaded at OCO-2 Version 10 SIF and column CO₂ data can be downloaded at MODIS burned area data can be downloaded at (Please see Section 4.1 of the User's Manual for details -
Funding AgencyGrant Number
Ministry of Science and Technology (Taipei)108-2111-M-001-011-MY3
Academia SinicaAS-IA-109-M03
Subject Keywords:Photosynthesis; burned area; vapor pressure deficit; biosphere-atmosphere exchange
Issue or Number:1
Record Number:CaltechAUTHORS:20211210-240694000
Persistent URL:
Official Citation:Albright, R., Corbett, A., Jiang, X., Creecy, E., Newman, S., Li, K.-F., et al. (2022). Seasonal variations of solar-induced fluorescence, precipitation, and carbon dioxide over the Amazon. Earth and Space Science, 9, e2021EA002078.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112361
Deposited By: George Porter
Deposited On:10 Dec 2021 20:02
Last Modified:24 Jan 2022 22:38

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