Satellite Constraints on the Latitudinal Distribution and Temperature Sensitivity of Wetland Methane Emissions
Name
AGU Advances - 2021 - Ma - Satellite Constraints on the Latitudinal Distribution and Temperature Sensitivity of Wetland.pdf
Description
Published version
Size
1.03 MB
Format
Adobe PDF
Checksum (MD5)
788bfbfa0a6f413745cd56f48d552da4
Author(s)
Ma, Shuang
Worden, John R
Bloom, A Anthony
Zhang, Yuzhong
Poulter, Benjamin
Cusworth, Daniel H
Yin, Yi
Pandey, Sudhanshu
Maasakkers, Joannes D
Lu, Xiao
Date Issued
September 15, 2021
Journal
AGU Advances
Publisher
American Geophysical Union
Citation
Ma, S., Worden, J. R., Bloom, A. A., Zhang, Y., Poulter, B., Cusworth, D. H., et al. (2021). Satellite constraints on the latitudinal distribution and temperature sensitivity of wetland methane emissions. AGU Advances, 2, e2021AV000408.
Version
Final published version
Abstract
Wetland methane (CH4) emissions comprise about one-third of the global CH4 source. The latitudinal distribution and climate sensitivity of wetland CH4 fluxes are the key determinants of the global CH4-climate feedback. However, large differences exist between bottom-up estimates, informed by ground-based flux measurements, and top-down estimates derived from spaceborne total column CH4. Despite the extensive coverage of satellite CH4 concentration observations, challenges remain with using top-down estimates to test bottom-up models, mainly because of the uncertainties in the satellite retrievals, the model representation errors, the variable prior emissions, and the confounding role of the posterior error covariance structures. Here, we use satellite-based top-down CH4 flux estimates (2010–2012) to test and refine 42 bottom-up estimates of wetland emissions that use a range of hypothesized wetland extents and process controls. Our comparison between bottom-up models and satellite-based fluxes innovatively accounts for cross-correlations and spatial uncertainties typically found in top-down inverse estimates, such that only the information from satellite observations and the atmospheric transport model is kept as a constraint. We present a satellite-constrained wetland CH4 ensemble product derived from assembling the highest-performance bottom-up models, which estimates global wetland CH4 emissions of 148 (117–189, 5th–95th percentile) Tg CH4 yr−1. We find that tropical wetland emissions contribute 72% (63%–85%) to the global wetland total. We also find that a lower-than-expected temperature sensitivity agrees better with atmospheric CH4 measurements. Overall, our approach demonstrates the potential for using satellites to quantitatively refine bottom-up wetland CH4 emission estimates, their latitudinal distributions, and their sensitivity to climate.
MIT Department
Massachusetts Institute of Technology. Center for Global Change Science
Terms of Use
Creative Commons Attribution-NonCommercial
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1029/2021av000408
