Articles | Volume 9, issue 6
https://doi.org/10.5194/amt-9-2445-2016
https://doi.org/10.5194/amt-9-2445-2016
Research article
 | 
02 Jun 2016
Research article |  | 02 Jun 2016

Update on GOSAT TANSO-FTS performance, operations, and data products after more than 6 years in space

Akihiko Kuze, Hiroshi Suto, Kei Shiomi, Shuji Kawakami, Makoto Tanaka, Yoko Ueda, Akira Deguchi, Jun Yoshida, Yoshifumi Yamamoto, Fumie Kataoka, Thomas E. Taylor, and Henry L. Buijs

Abstract. A data set containing more than 6 years (February 2009 to present) of radiance spectra for carbon dioxide (CO2) and methane (CH4) observations has been acquired by the Greenhouse gases Observing SATellite (GOSAT, available at http://data.gosat.nies.go.jp/GosatUserInterfaceGateway/guig/GuigPage/open.do), nicknamed “Ibuki”, Thermal And Near infrared Sensor for carbon Observation Fourier Transform Spectrometer (TANSO-FTS). This paper provides updates on the performance of the satellite and TANSO-FTS sensor and describes important changes to the data product, which has recently been made available to users. With these changes the typical accuracy of retrieved column-averaged dry air mole fractions of CO2 and CH4 (XCO2 and XCH4, respectively) are 2 ppm or 0.5 % and 13 ppb or 0.7 %, respectively. Three major anomalies of the satellite system affecting TANSO-FTS are reported: a failure of one of the two solar paddles in May 2014, a switch to the secondary pointing system in January 2015, and most recently a cryocooler shutdown and restart in August 2015. The Level 1A (L1A) (raw interferogram) and the Level 1B (L1B) (radiance spectra) of version V201 described here have long-term uniform quality and provide consistent retrieval accuracy even after the satellite system anomalies. In addition, we discuss the unique observation abilities of GOSAT made possible by an agile pointing mechanism, which allows for optimization of global sampling patterns.

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Short summary
A more than 6-year data set has been acquired by TANSO-FTS onboard GOSAT. This paper provides updates on the performance and describes important changes to the data product for the typical accuracy of retrieved CO2 and CH4 of 2 ppm and 13 ppb, respectively. The V201 Level 1B have long-term uniform quality and provide consistent retrieval accuracy even after the three anomalies of the satellite system. In addition, we discuss the unique observation abilities by an agile pointing mechanism.