Fumie Kawazoe

GOSAT higher level product status 1.5 year after the launch

After the 1.5 year operation of GOSAT (Greenhouse gases Observing SATellite), NIES GOSAT DHF (GOSAT Data Handling Facility of National Institute for Environmental Studies) has been producing CAI Level 1B and 1B+, FTS/CAI Level 2, and FTS/CAI Level 3 products, receiving FTS Level 1A/1B and CAI Level 1A data from JAXA (FTS: Fourier Transform Spectrometer; CAI: Cloud and Aerosol Imager; JAXA: Japan Aerospace Exploration Agency). In addition to the higher level data processing, GOSAT DHF has the following additional roles: 1) Data archive and distribution, and 2) Observational request collection from users and their submission to JAXA. After calibration and preliminary validation, the processed data are distributed to RA users at the first stage (RA users: researchers engaging in Research Announcement). The processed data are validated and then they are distributed to General Users (GU). All the distribution is carried out through the GOSAT User Interface Gateway (GUIG). As of August 2010, the total number of user registration exceeds 900, and a large number of products are distributed both to the RA users and GU. At this moment, validation indicates that the FTS SWIR L2 CO2 and CH4 data show slightly lower values than validation results. Therefore, further improvement of the algorithm is planned as a next version of the FTS L2 products. FTS TIR data processing is still on the way.

Update of the GOSAT higher level products 2.5 years after the launch

During the 2.5 year operation of GOSAT (Greenhouse gases Observing SATellite), NIES GOSAT DHF (GOSAT Data Handling Facility of National Institute for Environmental Studies) has been producing CAI Level 1B and 1B+, FTS Level 2 SWIR (column amount of CO2 and CH4), CAI Level 2 (cloud flag ), FTS Level 3 products (global map of XCO2, XCH4,) and CAI Level 3 (global radiance and global reflectance), receiving FTS Level 1A/1B, and CAI Level 1A data from JAXA (FTS: Fourier Transform Spectrometer; CAI: Cloud and Aerosol Imager, JAXA: Japan Aerospace eXploration Agency). In addition, FTS Level 2 TIR are released to RA users. FTS Level 3 TIR, and Level 4A and 4B products (emission/absorption and 3D global distribution of CO2) will be released in the near future.. Since the FTS Level 2 SWIR data have been accumulated more than 2.5 years, global trends can be observed, while the validation results show negative bias of 2 to 3 % for CO2 and negative bias of 1 to 2 % for CH4. A comparison with the results by different algorithms is also conducted. All the mentioned data products are distributed through a website, the GOSAT User Interface Gateway (GUIG), and users of the products include the researchers responded to the three Research Announcements (RA) and general users (GU). Number of the RA users exceeds 100 and that for GU exceeds 1100.

GOSAT higher level products and the variation of retrieved XCO2 and XCH4

During the 3.5-year operation of GOSAT (Greenhouse gases Observing SATellite), NIES GOSAT DHF (GOSAT Data Handling Facility of National Institute for Environmental Studies) has been producing some standard products from the data of TANSO-CAI (TANSO: Thermal And Near-infrared Sensor for carbon Observation; CAI: Cloud and Aerosol Imager) and TANSO-FTS (Fourier Transform Spectrometer). The standard data products of CAI Level 1B/1B+, FTS Level 2 SWIR (column amount of CO2 and CH4), FTS Level 2 TIR (profiles of CO2 and CH4 concentration), CAI Level 2 (cloud flag), FTS Level 3 (global map of XCO2, XCH4), and CAI Level 3 (global radiance and global reflectance) have been provided to general users. In addition, CAI Level 3 NDVI (Normalized Difference Vegetation Indices) and FTS Level 4A (flux of CO2) are released to GOSAT RA (Research Announcement) researchers and Model Group RA users, respectively. Since the FTS Level 2 SWIR data have been accumulated more than three years, global distribution and the timely changes of greenhouse gases are observed. In 2012, the version up of FTS Level 1B and FTS Level 2 SWIR has been carried out and the data quality of the new version has been significantly improved.

GOSAT higher level product status more than 1.5 years after the launch and planned improvement

After the 1.5 year operation of GOSAT (Greenhouse gases Observing SATellite), NIES GOSAT DHF (GOSAT Data Handling Facility of National Institute for Environmental Studies) has been producing CAI Level 1B and 1B+, FTS/CAI Level 2 and FTS/CAI Level 3 products, receiving FTS Level 1A/1B, and CAI Level 1A data from JAXA ( FTS: Fourier Transform Spectrometer; CAI: Cloud and Aerosol Imager; JAXA: Japan Aerospace Exploration Agency). In addition to the higher level data processing, GOSAT DHF has several additional roles 1) observation request collection from users and their submission to JAXA 2) Data archive and 3) Data Distribution. After the calibration and preliminary validation, processed data are distributed to RA researchers at first stage. Then, after the validation, they are distributed to General users. All the distribution is through GOSAT User Interface Gateway (GUIG). As of May of 2010, total number of user registration exceeds 800, and a large number of products are distributed both to the RA researchers and to General Users. At this moment, validation indicates that the FTS L2 SWIR CO2 and CH4 data show slightly lower values than validation results. In addition, very high XCO2 values, which seemed caused by aerosol, appeared on some desert area. But, further improvement of the algorithm was conducted as version 01.XX of FTS L2 products. Preliminary FTS TIR L2 processing is being conducted and TIR processing is starting. In addition to the L2 products, some Level 3 products are going to be released: FTS L3 global distribution of CO2 and CH4, and CAI L3 global radiance distribution.

Current status of GOSAT higher level products by NIES GOSAT DHF

GOSAT ( Ibuki ) was successfully launched on January 23, 2009 and has been operating nominally. NIES GOSAT DHF ( Data Handling Facility) , receiving GOSAT Level 1 data of TANSO-FTS ( Fourier Transform Spectrometer) and TANSO-CAI ( Cloud and Aerosol Imager), started checking them and generating Higher Level Products of GOSAT. The Products include Level 1B and 1B+ of CAI and Level 2 ( CO2 and CH4 column amount from SWIR and TIR from FTS and , cloud flag, aerosol and cloud properties from CAI).

An update on GOSAT standard products at five-and-a-half years after the launch

GOSAT has been operated more than 5.5 years after its launch on January 23, 2009. Receiving TANSO-FTS Level 1A/1B data and TANSO-CAI Level 1A data from JAXA (FTS: Fourier Transform Spectrometer; CAI: Cloud and Aerosol Imager, JAXA: Japan Aerospace eXploration Agency), National Institute for Environmental Studies (NIES) has provided various kinds of Standard data products such as FTS SWIR Level 2 (XCO2 and XCH4: column concentrations of CO2 and CH4), FTS TIR Level 2 (vertical profiles of CO2 and CH4 concentration), FTS Level 4A (global CO2 flux), FTS Level 4B (global CO2 distribution), CAI Level 1B/1B+, and CAI Level 2 (cloud flag). After the latest updates of FTS Level 1 products to V161.160 (Version 161.160) by JAXA in 2013, now FTS SWIR Level 2 products are available as V02.21 (Version 02.21) for the entire period from April 2009 to May 2014. In March 2014, FTS Level 4 products of CO2 (V02.02) were processed with FTS Level 2 (V02.21) for the period of June 2009 to October 2011. FTS Level 4 products of CH4 (V01.01) were newly added to the Standard products and are available for 2 years from June 2009. FTS TIR Level 2 products (V01.0x) were updated in August 2014 and delivered to general users for 2.5 years from January 2010. There were some minor changes in their data format. After improving product search functions with an interactive map operation in GUIG (GUIG: GOSAT User Interface Gateway), general users are able to find and download these Standard products for their concerning area much easily.