JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

A (Atmospheric and Hydrospheric Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS04] [EE] Global Carbon Cycle Observation and Analysis

Tue. May 23, 2017 1:45 PM - 3:15 PM 301B (International Conference Hall 3F)

convener:Nobuko Saigusa(National Institute for Environmental Studies), Prabir Patra(Research Institute for Global Change, JAMSTEC), Toshinobu Machida(National Institute for Environmental Studies), David Crisp(Jet Propulsion Laboratory), Chairperson:Nobuko Saigusa(National Institute for Environmental Studies)

2:15 PM - 2:30 PM

[AAS04-15] The Orbiting Carbon Observatory (OCO-2) tracks 2-3 peta-gram increase in carbon release to the atmosphere during the 2014-2016 El Niño

*Prabir Patra1 (1.Department of Environmental Geochemical Cycle Research, JAMSTEC)


The powerful El Niño event of 2015-2016 – the third most intense since the 1950s – has exerted a large impact on the Earth’s natural climate system. The column-averaged CO2 dry-air mole fraction (XCO2) observations from satellites and ground-based networks are analyzed together with in situ observations for the period of September 2014 to October 2016. From the differences between satellite (OCO-2) observations and simulations using an atmospheric chemistry-transport model, we estimate that, relative to the mean annual fluxes for 2013, over the period July 2015 to June 2016, the most recent El Niño has contributed to an excess CO2 emission from the Earth’s surface (land+ocean) to the atmosphere in the range of 2.4 ± 0.2 PgC (1 Pg = 1015 g). The excess CO2 flux resulted primarily from reduction in vegetation uptake due to drought, and to a lesser degree from increased biomass burning. It is about the half of the CO2 flux anomaly (range: 4.4-6.7 PgC) estimated for the 1997/1998 El Niño. The annual total sink is estimated to be 3.9 ± 0.2 PgC for the assumed fossil fuel emission of 10.1 PgC. The major uncertainty in attribution arise from error in anthropogenic emission trends, satellite data and atmospheric transport.