[A-CG49] Greenhouse Gas Monitoring from Space: Current Capabilities, Challenges, and Future Needs

[ACG49-P03] Observations of the Tropical Land Biosphere response to the 2015-2016 El Niño with the Orbiting Carbon Observatory-2 (OCO-2) and Greenhouse gases Observing SATellite (GOSAT)

*David Crisp¹ (1.Jet Propulsion Laboratory, California Institute of Technology)

キーワード：Orbiting Carbon Observatory-2, Greenhouse gases Observing SATellite, Carbon dioxide, Solar induced chlorophyll fluorescence

The first two years of the OCO-2 mission were dominated by the record-setting 2015–2016 El Niño. OCO-2 measurements were combined with GOSAT observations and analyzed to yield high spatial resolution estimates of the column-averaged dry air mole fraction, XCO₂, These products clearly resolved reductions in tropical ocean outgassing from net increases in CO₂ emissions from tropical forests. These XCO₂ estimates were combined with OCO-2 and GOSAT solar-induced chlorophyll fluorescence (SIF) measurements to trace the origin of the forest CO₂ emissions to the impacts of drought, temperature stress, and fires. Observations acquired between 2017-2019 documented the atmospheric CO₂ response following this El Niño when, unexpectedly, its XCO₂ and SIF measurements showed that the natural carbon cycle never fully recovered to the state anticipated by most earlier carbon cycle measurements and models. In particular, tropical forests, once thought to be significant CO₂ sinks, continued to be persistent net sources of CO₂ throughout this period. Understanding these results and their implications for the response of the natural carbon cycle to climate change requires longer continuous records of CO₂ and SIF.