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

Wu, Lianghai; Hasekamp, Otto; Hu, Haili; Landgraf, Jochen; Butz, Andre; Brugh, Joost aan de; Aben, Ilse; Pollard, Dave F.; Griffith, David W. T.; Feist, Dietrich G.; Koshelev, Dmitry; Hase, Frank; Toon, Geoffrey C.; Ohyama, Hirofumi; Morino, Isamu; Notholt, Justus; Shiomi, Kei; Iraci, Laura; Schneider, Matthias; de Maziere, Martine; Sussmann, Ralf; Kivi, Rigel; Warneke, Thorsten; Goo, Tae-Young and Te, Yao (2018): Carbon dioxide retrieval from OCO-2 satellite observations using the RemoTeC algorithm and validation with TCCON measurements. In: Atmospheric Measurement Techniques, Vol. 11, No. 5: pp. 3111-3130

Abstract

In this study we present the retrieval of the column-averaged dry air mole fraction of carbon dioxide (X-CO2) 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 X-CO2, 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 spec tral bands of OCO-2 significantly improved the retrieval. Based on a small correlation of the X-CO2, error over land with goodness of fit, we applied an a posteriori bias correction to our OCO-2 retrievals. In overpass averaged results, X-CO2, retrievals have an SD of similar to 1.30 ppm and a station-tostation variability of similar to 0.40 ppm among collocated TCCON sites. The seasonal relative accuracy (SRA) has a value of 0.52 ppm. The validation shows relatively larger difference with TCCON over high-latitude areas and some specific regions like Japan.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 1867-1381
• Language: English