Global Patterns of Carbon Dioxide Variability from Satellite Observations

Abstract

Advanced satellite technology has been providing unique observations of global carbon dioxide (CO2) concentrations. These observations have revealed important CO2 variability at different timescales and over regional and planetary scales. Satellite CO2 retrievals have revealed that stratospheric sudden warming and the Madden-Julian Oscillation can modulate atmospheric CO2 concentrations in the mid-troposphere. Atmospheric CO2 also demonstrates variability at interannual timescales. In the tropical region, the El Niño–Southern Oscillation and the Tropospheric Biennial Oscillation can change atmospheric CO2 concentrations. At high latitudes, mid-tropospheric CO2 concentrations can be influenced by the Northern Hemispheric annular mode. In addition to modulations by the large-scale circulations, sporadic events such as wildfires, volcanic eruptions, and droughts, which change CO2 surface emissions, can cause atmospheric CO2 concentrations to increase significantly. The natural variability of CO2 summarized in this review can help us better understand its sources and sinks and its redistribution by atmospheric motion. ▪ Global satellite CO2 data offer a unique opportunity to explore CO2 variability in different regions. ▪ Atmospheric CO2 concentration demonstrates variations at intraseasonal, seasonal, and interannual timescales. ▪ Both large-scale circulations and variations of surface emissions can modulate CO2 concentrations in the atmosphere.

Temperature, carbon dioxide and methane

“…The seasonal cycle of carbon dioxide is typically ascribed to the cycles of terrestrial productivity on the large land masses of the Northern Hemisphere, generating high seasonal amplitude at Arctic sites such as Barrow and Alert and with low amplitude at the South Pole and other Antarctic sites (Keeling et al 1989;Keeling et al 2001Keeling et al , 2005Buermann et al 2007;Keeling 2008;IPCC 2013;He et al 2017;Jiang & Yung 2019). Similarly, the seasonal cycle of methane is typically ascribed to the cycle of wetland and agricultural and livestock production (with large sources on the land masses of the Northern Hemisphere) and to destruction by the OH radical in summer months in each Hemisphere (Fung et al 1991;Dlugokencky et al 1994).…”

Quantification of Enhancement in Atmospheric CO2 Background Due to Indian Biospheric Fluxes and Fossil Fuel Emissions

“…Observations (either ground‐based or instruments mounted onboard satellite) should capture this enhancement so that it can offer a better constrain in the inverse estimations. The satellites’ efficiency in observing enhancement of the Indian sources and sinks mixed in the global atmospheric CO 2 is crucial too, given geospatial limitations such as cloud cover hindering the direct satellite observations over India and surroundings (Janardanan et al., 2016; Jiang & Yung, 2019). In this context, the present study examines the maximum areal extent over which the Indian CO 2 enhancement is discernible in a particular measurement.…”

“…Satellite observations such as greenhouse gases observing satellite (GOSAT: Kuze et al., 2009) and orbiting carbon observatory‐2 (OCO‐2: Crisp et al., 2004; Jiang & Yung, 2019; Miller et al., 2007) provide global measurements of column‐averaged CO 2 dry‐air mole fraction data sets for a better scientific understanding of regional carbon cycle processes and carbon budgets. However, satellite observations are known to have substantial data gaps due to geophysical limitations like the presence of clouds and aerosols in the atmosphere (Alkhaled et al., 2008; Barkley et al., 2006; Bösch et al., 2006; Buchwitz et al., 2005; Byrne et al., 2017; Engelen & McNally, 2005; Miller et al., 2007; Tiwari et al., 2006).…”

Effect of the Atlantic Meridional Overturning Circulation on Atmospheric pCO2 Variations

“…The effect of the natural variability is much lower than the forced trend on such relatively short time scales. For example, the El Niño-Southern Oscillation (ENSO), a dominant mode of interannual climate variability, induces atmospheric pCO 2 variations of only 1-2 ppmv (Jiang and Yung, 2019). Most studies seek to explain such variations in pCO 2 as a forced response of the carbon cycle to changes in external conditions.…”