Inverse modeling of global and regional CH4 emissions using SCIAMACHY satellite retrievals

作者：P. Bergamaschi, Christian Frankenberg, Jan Fokke Meirink, Maarten Krol, Marco Villani, Sander Houweling, Frank Dentener, E. J. Dlugokencky, John Bharat Miller, Luciana V. Gatti, Andreas Engel, Ingeborg Levin · 发表于：Journal of Geophysical Research Atmospheres · 年份：2009 · DOI：10.1029/2009jd012287 · 被引用次数：577 · 研究领域：Atmospheric and Environmental Gas Dynamics、Atmospheric Ozone and Climate、Atmospheric chemistry and aerosols

Methane retrievals from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instrument onboard ENVISAT provide important information on atmospheric CH4 sources, particularly in tropical regions which are poorly monitored by in situ surface observations. Recently, Frankenberg et al. (2008a, 2008b) reported a major revision of SCIAMACHY retrievals due to an update of spectroscopic parameters of water vapor and CH4. Here, we analyze the impact of this revision on global and regional CH4 emissions estimates in 2004, using the TM5‐4DVAR inverse modeling system. Inversions based on the revised SCIAMACHY retrievals yield ∼20% lower tropical emissions compared to the previous retrievals. The new retrievals improve significantly the consistency between observed and assimilated column average mixing ratios and the agreement with independent validation data. Furthermore, the considerable latitudinal and seasonal bias correction of the previous SCIAMACHY retrievals, derived in the TM5‐4DVAR system by simultaneously assimilating high‐accuracy surface measurements, is reduced by a factor of ∼3. The inversions result in significant changes in the spatial patterns of emissions and their seasonality compared to the bottom‐up inventories. Sensitivity tests were done to analyze the robustness of retrieved emissions, revealing some dependence on the applied a priori emission inventories and OH fields. Furthermore, we performed a detailed validation of simulated ...