Spatiotemporal Variability of CO2, Solar-Induced Fluorescence, And Precipitation Over the Tropical Rainforests

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dc.contributor.advisorJiang, Xun
dc.contributor.committeeMemberLi, Liming
dc.contributor.committeeMemberWang, Yuxuan
dc.contributor.committeeMemberChoi, Yunsoo
dc.creatorAlbright, Ronald Joe
dc.creator.orcid0000-0001-5003-9366
dc.date.accessioned2024-01-24T16:25:29Z
dc.date.createdAugust 2023
dc.date.issued2023-08
dc.date.updated2024-01-24T16:25:30Z
dc.description.abstractTropical rainforest ecosystems change forest dynamics during the dry/fire season, transitioning from an atmospheric CO2 sink to a CO2 source. The Amazon basin, Congo basin, and the tropical Indo-Pacific play vital roles in biospheric processes, which contribute to Earth’s atmospheric CO2 concentration. This investigation will use various space-based and ground-based datasets and empirical models to explore photosynthetic activity, spatiotemporal variability, and correlation among critical variables (e.g., Solar-induced chlorophyll fluorescence (SIF), CO2, precipitation, high vapor pressure deficit (VPD), and burned areas). Specifically, we use Orbiting Carbon Observatory 2 (OCO-2) SIF, OCO-2 CO2, Global Precipitation Climatology Project (GPCP) precipitation, Moderate Resolution Imaging Spectrometer (MODIS) burned area, and CarbonTracker Model. Over the entire Amazon basin from September 2014 to December 2019, we found a positive temporal correlation (0.94) between OCO-2 SIF and GPCP precipitation and a negative temporal correlation (–0.64) between OCO-2 SIF and OCO-2 CO2. These findings suggest that precipitation enhances photosynthesis, thus resulting in higher values for SIF and the rate of removal of atmospheric CO2 in the Amazon region. We also identify seasonal variations in the spatial distributions of these variables across the Amazon region. Over the Congo basin, during the same timeframe (Sep 2014-Dec 2019), we find that the atmospheric CO2 is ~2 ppm higher than the regional background during the boreal summer (June–August), primarily due to biomass burning and significantly reduced photosynthetic activities during the dry season. Over the tropical Indo-Pacific, we explore the spatial distributions of SIF, CO2, and precipitation during El Niño events verse other months. The CarbonTracker Model is employed to assess the impact of El Niño on atmospheric CO2. Various datasets of deseasonalized precipitation, deseasonalized SIF, and deseasonalized CO2 are analyzed in time series averaged over 10S-10N, 100E-160E. We have discovered that there is less precipitation, more sinking air, lower SIF, and higher CO2 over the Indo-Pacific region during the El Niño events. The CarbonTracker model can simulate the increase of atmospheric column CO2 during the El Niño event, although there are some difficulties in capturing the correct spatial distribution of CO2 anomalies. These findings suggest that improved seasonal fire management practices in these tropical regions are critical components needed to achieve successful and timely reductions in global carbon emissions, as set forth by international agreements.
dc.description.departmentEarth and Atmospheric Sciences, Department of
dc.format.digitalOriginborn digital
dc.format.mimetypeapplication/pdf
dc.identifier.citationPortions of this document appear in: Albright, Ronald, Abigail Corbett, Xun Jiang, Ellen Creecy, Sally Newman, King‐Fai Li, Mao‐Chang Liang, and Yuk L. Yung. "Seasonal Variations of Solar‐Induced Fluorescence, Precipitation, and Carbon Dioxide Over the Amazon." Earth and Space Science 9, no. 1 (2022): e2021EA002078; and in: Jiang, Xun, Ronald Albright, Ellen Creecy, King‐Fai Li, Mao‐Chang Liang, Sally Newman, Xinyue Wang, Thishan Dharshana Karandana Gamalathge, and Yuk L. Yung. "Congo basin rainforest is a net carbon source during the dry season." Earth and Space Science 10, no. 2 (2023): e2022EA002644; and in: Albright, R., Dharshana, T., Gamalathge, K., Jiang, X., Li, L., (2023). Investigating the Impact of El Niño Southern Oscillation (Enso) on CO2 and SIF over the Indo-Pacific Region. Submitted to Earth & Space Science (ESS), (June) (22), 2023EA003126.
dc.identifier.urihttps://hdl.handle.net/10657/16026
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectCO2
dc.subjectSolar-induced chlorophyll fluorescence (SIF)
dc.subjectprecipitation
dc.subjectvapor pressure deficit (VPD)
dc.subjectburned area
dc.subjectphotosynthetic activity
dc.subjectCO2 sink
dc.subjectCO2 source
dc.subjectOCO-2
dc.subjectMODIS
dc.subjectGPCP
dc.subjectENSO
dc.subjectsouthern oscillation index (SOI)
dc.subjecttropical rain-forest
dc.subjectAmazon basin
dc.subjectCongo basin
dc.subjecttropical Indo-Pacific
dc.subjectbiosphere
dc.subjectCO2 emissions
dc.titleSpatiotemporal Variability of CO2, Solar-Induced Fluorescence, And Precipitation Over the Tropical Rainforests
dc.type.dcmitext
dc.type.genreThesis
dcterms.accessRightsThe full text of this item is not available at this time because the student has placed this item under an embargo for a period of time. The Libraries are not authorized to provide a copy of this work during the embargo period.
local.embargo.lift2025-08-01
local.embargo.terms2025-08-01
thesis.degree.collegeCollege of Natural Sciences and Mathematics
thesis.degree.departmentEarth and Atmospheric Sciences, Department of
thesis.degree.disciplineAtmospheric Sciences
thesis.degree.grantorUniversity of Houston
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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