Carbon dioxide retrieval from OCO-2 satellite observations using the RemoTeC algorithm and validation with TCCON measurements

Lianghai Wu, Otto Hasekamp, Haili Hu, Jochen Landgraf, Andre Butz, Joost aan de Brugh, Ilse Aben, Dave F. Pollard, David W. T. Griffith, Dietrich G. Feist, Dmitry Koshelev, Frank Hase, Geoffrey C. Toon, Hirofumi Ohyama, Isamu Morino, Justus Notholt, Kei Shiomi, Laura Iraci, Matthias Schneider, Martine de MaziereRalf Sussmann, Rigel Kivi, Thorsten Warneke, Tae-Young Goo, Yao Te

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

In this study we present the retrieval of the column-averaged dry air mole fraction of carbon dioxide (XCO2) from the Orbiting Carbon Observatory-2 (OCO-2) satellite observations using the RemoTeC algorithm, previously successfully applied to retrieval of greenhouse gas concentration from the Greenhouse Gases Observing Satellite (GOSAT). The XCO2 product has been validated with collocated ground-based measurements from the Total Carbon Column Observing Network (TCCON) for almost 2 years of OCO-2 data from September 2014 to July 2016. We found that fitting an additive radiometric offset in all three spectral bands of OCO-2 significantly improved the retrieval. Based on a small correlation of the XCO2 error over land with goodness of fit, we applied an a posteriori bias correction to our OCO-2 retrievals. In overpass averaged results, XCO2 retrievals have an SD of  ∼ 1.30ppm and a station-to-station variability of  ∼ 0.40ppm among collocated TCCON sites. The seasonal relative accuracy (SRA) has a value of 0.52ppm. The validation shows relatively larger difference with TCCON over high-latitude areas and some specific regions like Japan.
Original languageEnglish
Pages (from-to)3111-3130
Number of pages20
JournalAtmospheric Measurement Techniques
Volume11
Issue number5
DOIs
Publication statusPublished - 30 May 2018

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