Title
Assimilation of GOSAT Methane in the Hemispheric CMAQ; Part I: Design of the Assimilation System
Abstract
We present a parametric Kalman filter data assimilation system using GOSAT methane observations within the hemispheric CMAQ model. The assimilation system produces forecasts and analyses of concentrations and explicitly computes its evolving error variance while remaining computationally competitive with other data assimilation schemes such as 4-dimensional variational (4D-Var) and ensemble Kalman filter (EnKF). The error variance in this system is advected using the native advection scheme of the CMAQ model and updated at each analysis while the error correlations are kept fixed. We discuss extensions to the CMAQ model to include methane transport and emissions (both anthropogenic and natural) and perform a bias correction for the GOSAT observations. The results using synthetic observations show that the analysis error and analysis increments follow the advective flow while conserving the information content (i.e., total variance). We also demonstrate that the vertical error correlation contributes to the inference of variables down to the surface. In a companion paper, we use this assimilation system to obtain optimal assimilation of GOSAT observations.
Year
DOI
Venue
2022
10.3390/rs14020371
REMOTE SENSING
Keywords
DocType
Volume
chemical data assimilation, methane, GOSAT, parametric Kalman filter
Journal
14
Issue
Citations 
PageRank 
2
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Sina Voshtani100.68
Richard Ménard200.68
Thomas W. Walker300.68
Amir Hakami400.68