B007-09
Cropland carbon uptake delayed and reduced by 2019 Midwest floods

Monday, 7 December 2020: 06:02
Virtual
Yi Yin1, Brendan K Byrne2, Junjie Liu3, Paul O Wennberg1, Kenneth J Davis4, Troy Magney5, Philipp Koehler6, Liyin He6, Rupesh Jeyaram7, Vincent Humphrey8, Tobias Gerken9, Sha Feng10, Joshua P DiGangi11 and Christian Frankenberg12, (1)California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, United States, (2)Jet Propulsion Laboratory, Pasadena, CA, United States, (3)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (4)The Pennsylvania State University, University Park, PA, United States, (5)University of California Davis, Plant Sciences, Davis, CA, United States, (6)California Institute of Technology, Pasadena, CA, United States, (7)California Institute of Technology, Pasadena, MA, United States, (8)ETH Swiss Federal Institute of Technology Zurich, Zurich, Switzerland, (9)University of Bayreuth, Bayreuth, Germany, (10)The Pennsylvania State University, Department of Meteorology and Atmospheric Science, University Park, PA, United States, (11)NASA Langley Research Center, Hampton, VA, United States, (12)NASA Jet Propulsion Laboratory, Pasadena, CA, United States
Recorded Presentation
Abstract:
While large-scale floods directly impact human lives and infrastructures, they also profoundly impact agricultural productivity. New satellite observations of vegetation activity and atmospheric CO2 offer the opportunity to quantify the effects of such extreme events on cropland carbon sequestration. Widespread flooding during spring and early summer 2019 induced conditions that delayed crop planting across the U.S. Midwest. As a result, satellite observations of solar-induced chlorophyll fluorescence (SIF) from TROPOspheric Monitoring Instrument (TROPOMI) and Orbiting Carbon Observatory (OCO-2) reveal a 16-day shift in the seasonal cycle of photosynthesis relative to 2018, along with a 15% lower peak value. We estimate a reduction of -0.21 PgC in gross primary productivity (GPP) in June and July, partially compensated in August and September (+0.14 PgC). The extension of the 2019 growing season into late September is likely to have benefited from increased water availability and late-season temperature. Ultimately, this change is predicted to reduce the crop productivity in the Midwest Corn/Soy belt by ~15% compared to 2018. Using an atmospheric transport model, we show that a decline of ~0.1 PgC in the net carbon uptake during June and July is consistent with observed CO2 enhancements of up to 10 ppm in the midday boundary layer from Atmospheric Carbon and Transport - America (ACT-America) aircraft and over 3 ppm in column-averaged dry-air mole fractions from OCO-2. This study quantifies the impact of floods on cropland productivity and demonstrates the potential of combining SIF with atmospheric CO2 observations to monitor regional carbon flux anomalies.
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