The Fusion Algorithm of XCO2 Products: Applied to GOSAT

The Greenhouse Gases Observing Satellite (GOSAT) is the world's first spacecraft to measure the concentrations of CO
2
from space and it has high-precision hyperspectral atmospheric CO
2
monitoring from 2009. Several atmospheric CO
2
products, such as ACOS, NIES, OCFP and SRFP products from full physics retrieval algorithm, both provide XCO
2
(the column-average dry-air mole fraction of atmospheric CO
2
) of GOSAT. These products have different characteristics and advantages and have different performance in different regions. In order to obtain the XCO
2
data set with high precision, low uncertainty and high coverage, the maximum likelihood estimation (MLE) method is used to fuse GOSAT XCO
2
products. The algorithm takes into account the uncertainty of each product on each pixel, and is applied from April 2009 to December 2015. The validation result between fusion XCO
2
and Total Carbon Column Observing Network XCO
2
shows R = 0.843 and RMSE = 3.248.