衛星によるメタン排出量の把握で各国の削減目標達成を支援(An Audit from Orbit: Satellites Help Countries Count the Methane They Miss)

2026-11-02 ハーバード大学

米国ハーバード大学の研究チームは、衛星観測データと各国の温室効果ガス排出インベントリを統合し、メタン排出量を高精度に推定するシステム「Integrated Methane Inversion(IMI)」を開発・活用している。このシステムは、各国が報告する家畜、石油・天然ガス採掘、廃棄物処理、農業などの排出量を初期値とし、気象データを用いて大気中のメタンの移動を予測する。その結果を、衛星搭載センサーTROPOMIによる実際の大気中メタン濃度の観測値と比較し、排出量を修正する。解析では、2023年の世界の人為起源メタン排出量が、各国の国連報告値より約15%多いと推定された。また、オランダでは報告値の約2倍、カザフスタンでは石油・ガス採掘由来の排出量が過小評価されている可能性が示された。約12km四方の空間スケールで排出量を推定でき、各国の気候変動対策の評価や温室効果ガス削減目標の検証、国際的な排出量報告の精度向上への貢献が期待される。

<関連情報>

統合メタン逆解析(IMI)2.0:TROPOMI衛星観測データを用いて、世界中のメタン総排出量を高解像度でモニタリングするための、改良された研究・関係者向けツール Integrated Methane Inversion (IMI) 2.0: an improved research and stakeholder tool for monitoring total methane emissions with high resolution worldwide using TROPOMI satellite observations

Lucas A. Estrada, Daniel J. Varon, Melissa Sulprizio, Hannah Nesser, Zichong Chen, Nicholas Balasus, Sarah E. Hancock, Megan He, James D. East, Todd A. Mooring, Alexander Oort Alonso, Joannes D. Maasakkers, Ilse Aben, Sabour Baray, Kevin W. Bowman, John R. Worden, Felipe J. Cardoso-Saldaña, Emily Reidy, and Daniel J. Jacob
Geoscientific Model Development  Published:04 Jun 2025
DOI:https://doi.org/10.5194/gmd-18-3311-2025

https://gmd.copernicus.org/articles/18/3311/2025/gmd-18-3311-2025-f01
Figure 1Summary of major new features in IMI 2.0 divided into three categories: (a) expanded input options, (b) multiscale inversion capabilities, and (c) enriched output. Numbering of individual features corresponds to the relevant section in Sect. 3. The methane plume map in the top left panel is from Carbon Mapper (Methane Dashboard, Carbon Mapper Dashboard, 2024).

Abstract

Satellite observations of atmospheric methane are a powerful resource for quantifying methane emissions over any region worldwide. The inverse methods needed to infer emissions from these observations require a high level of scientific and technical expertise as well as access to large computational and data processing resources. The Integrated Methane Inversion (IMI) is an open-access cloud computing tool designed for researchers and non-expert users to obtain total sector-resolved methane emissions worldwide at up to 0.25°×0.3125° (≈25×25km-2) resolution by analytical inversion of TROPOMI satellite observations with closed-form error characterization. Here we describe IMI version 2.0 with vastly expanded capabilities relative to the original version. Major developments include (i) a new blended TROPOMI+GOSAT dataset for higher data quality, (ii) order-of-magnitude speed-up in Jacobian matrix construction, (iii) improved error characterization through use of super-observations, (iv) improved methods for initial and boundary conditions, (v) adaptive spatial resolution linked to observational information content, (vi) incorporation of point source observations in state vector construction, (vii) option to optimize tropospheric OH (main methane sink), (viii) global inversion capability, (ix) Kalman filter option for continuous monitoring of emissions, (x) updated default prior emission inventories, (xi) option for lognormal error probability density functions to characterize emissions, (xii) additional output visualization (sectoral emissions, temporal variability), and (xiii) containerization to facilitate download to local computing facilities and operation as part of the US GHG Center. A 2023 annual inversion with 28 d temporal resolution for the contiguous US (CONUS) is presented as a demonstration of IMI 2.0 capabilities.

1902環境測定
ad
ad
ad
タイトルとURLをコピーしました