Interannual variability on methane emissions in monsoon Asia derived from GOSAT and surface observations
Open Access
- 14 December 2020
- journal article
- research article
- Published by IOP Publishing in Environmental Research Letters
- Vol. 16 (2), 024040
- https://doi.org/10.1088/1748-9326/abd352
Abstract
In Asia, much effort is put into reducing methane (CH4) emissions due to the region's contribution to the recent rapid global atmospheric CH4 concentration growth. Accurate quantification of Asia's CH4 budgets is critical for conducting global stocktake and achieving the long-term temperature goal of the Paris Agreement. In this study, we present top-down estimates of CH4 emissions from 2009-2018 deduced from atmospheric observations from surface network and GOSAT satellite with the high-resolution global inverse model NIES-TM-FLEXPART-VAR. The optimized average CH4 budgets are 63.40 ± 10.52 Tg y−1 from East Asia (EA), 45.20 ± 6.22 Tg y−1 from Southeast Asia (SEA), and 64.35± 9.28 Tg y−1 from South Asia (SA) within the ten years. We analyzed two-five years CH4 emission budgets for three subregions and 13 top-emitting countries with an emission budget larger than 1 Tg y−1, and interannual variabilities for these subregions. Statistically significant increasing trends in emissions are found in EA with a lower emission growth rate during 2014-2018 compared to that during 2009-2013, while trends in SEA are not significant. In contrast to the prior emission, the posterior emission shows a significant decreasing trend in SA. The flux decrease is associated with the transition from strong La Niña (2010-11) to strong El Niño (2015-16) events, which modulate the surface air temperature and rainfall patterns. The interannual variability in CH4 flux anomalies was larger in SA compared to EA and SEA. The Southern Oscillation Index (SOI) correlates strongly with interannual CH4 flux anomalies for SA. Our findings suggest that the interannual variability in the total CH4 flux is dominated by climate variability in SA. The contribution of climate variability driving interannual variability in natural and anthropogenic CH4 emissions should be further quantified, especially for tropical countries. Accounting for climate variability may be necessary to improve anthropogenic emission inventories.This publication has 68 references indexed in Scilit:
- Inverse modelling of European CH4 emissions during 2006–2012 using different inverse models and reassessed atmospheric observationsAtmospheric Chemistry and Physics, 2018
- Adjoint of the global Eulerian–Lagrangian coupled atmospheric transport model (A-GELCA v1.0): development and validationGeoscientific Model Development, 2016
- Inverse modelling of CH4 emissions for 2010–2011 using different satellite retrieval products from GOSAT and SCIAMACHYAtmospheric Chemistry and Physics, 2015
- Atmospheric CH4 in the first decade of the 21st century: Inverse modeling analysis using SCIAMACHY satellite retrievals and NOAA surface measurementsJournal of Geophysical Research: Atmospheres, 2013
- Simulations of column-averaged CO2 and CH4 using the NIES TM with a hybrid sigma-isentropic (σ-θ) vertical coordinateAtmospheric Chemistry and Physics, 2013
- Inverse modeling of European CH4 emissions 2001–2006Journal of Geophysical Research: Atmospheres, 2010
- Modeling the soil consumption of atmospheric methane at the global scaleGlobal Biogeochemical Cycles, 2007
- Contribution of anthropogenic and natural sources to atmospheric methane variabilityNature, 2006
- Global carbon exchange and methane emissions from natural wetlands: Application of a process‐based modelJournal of Geophysical Research: Atmospheres, 1996
- Deduction of emissions of source gases using an objective inversion algorithm and a chemical transport modelPublished by American Geophysical Union (AGU) ,1993