Takashi Hamazaki

Thermal and near infrared sensor for carbon observation Fourier-transform spectrometer on the Greenhouse Gases Observing Satellite for greenhouse gases monitoring

The Greenhouse Gases Observing Satellite (GOSAT) monitors carbon dioxide (CO(2)) and methane (CH(4)) globally from space using two instruments. The Thermal and Near Infrared Sensor for Carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) detects gas absorption spectra of the solar short wave infrared (SWIR) reflected on the Earths surface as well as of the thermal infrared radiated from the ground and the atmosphere. TANSO-FTS is capable of detecting three narrow bands (0.76, 1.6, and 2.0 microm) and a wide band (5.5-14.3 microm) with 0.2 cm(-1) spectral resolution (interval). The TANSO Cloud and Aerosol Imager (TANSO-CAI) is an ultraviolet (UV), visible, near infrared, and SWIR radiometer designed to detect cloud and aerosol interference and to provide the data for their correction. GOSAT is placed in a sun-synchronous orbit 666 km at 13:00 local time, with an inclination angle of 98 degrees . A brief overview of the GOSAT project, scientific requirements, instrument designs, hardware performance, on-orbit operation, and data processing is provided.

Fourier transform spectrometer for Greenhouse Gases Observing Satellite (GOSAT)

Global warming has become a very serious issue for human beings. In 1997, the Kyoto Protocol was adopted at the Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP3), making it mandatory for developed nations to reduce carbon dioxide emissions by six (6) to eight (8) per cent of their total emissions in 1990, and to meet this goal sometime between 2008 and 2012. The Greenhouse gases Observing SATellite (GOSAT) is designed to monitor the global distribution of carbon dioxide (CO2) from the space. GOSAT is a joint project of Japan Aerospace Exploration Agency (JAXA), the Ministry of Environment (MOE), and the National Institute for Environmental Studies (NIES). JAXA is responsible for the satellite and instrument development, MOE is involved in the instrument development, and NIES is responsible for the satellite data retrieval. The satellite is scheduled to be launched in 2008. In order to detect the CO2 variation of boundary layers, both the technique to measure the column density and the retrieval algorithm to remove cloud and aerosol contamination are investigated. Main mission sensor of the GOSAT is a Fourier Transform Spectrometer with high optical throughput, spectral resolution and wide spectral coverage, and a cloud-aerosol detecting imager attached to the satellite. The paper presents the mission sensor system of the GOSAT together with the results of performance demonstration with proto-type instrument aboard an aircraft.

The instrumentation and the BBM test results of Thermal And Near infrared Sensor for carbon Observation (TANSO) on GOSAT

The Greenhouse gases Observing SATellite (GOSAT) is a satellite to monitor the carbon dioxide (CO2) and the methane (CH4) globally from orbit. GOSAT will be placed in a 666 km sun-synchronous orbit of 13:00 local time, with an inclination angle of 98 deg. Two instruments are accommodated on GOSAT. Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) detects the Short wave infrared (SWIR) reflected on the earths surface as well as the thermal infrared (TIR) radiated from the ground and the atmosphere. TANSO-FTS is capable of detecting wide spectral coverage, specifically, three narrow bands (0.76, 1.6, and 2 micron) and a wide band (5.5-14.3 micron) with 0.2 cm-1 spectral resolution. TANSO Cloud and Aerosol Imager (TANSO-CAI) is a radiometer of ultraviolet (UV), visible, and SWIR to correct cloud and aerosol interference. The paper presents the instrument design of TANSO-FTS/CAI, and test results using Bread Board Model (BBM) are presented.

Sensor system for Greenhouse Gas Observing Satellite (GOSAT)

Global warming has become a very serious issue for human beings. In 1997, the Kyoto Protocol was adopted at the Third Session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP3), making it mandatory for developed nations to reduce carbon dioxide emissions by six (6) to eight (8) per cent of their total emissions in 1990, and to meet this goal sometime between 2008 and 2012. The Greenhouse gases Observing SATellite (GOSAT) is design to monitor the global distribution of carbon dioxide (CO2) from orbit. GOSAT is a joint project of Japan Aerospace Exploration Agency (JAXA), the Ministry of Environment (MOE), and the National Institute for Environmental Studies (NIES). JAXA is responsible for the satellite and instrument development, MOE is involved in the instrument development, and NIES is responsible for the satellite data retrieval. The satellite is scheduled to be launched in 2008. In order to detect the CO2 variation of boundary layers, both the technique to measure the column density and the retrieval algorithm to remove cloud and aerosol contamination are investigated. Main mission sensor of the GOSAT is a Fourier Transform Spectrometer with high optical throughput, spectral resolution and wide spectral coverage, and a cloud-aerosol detecting imager attached to the satellite. The paper presents the mission sensor system of the GOSAT together with the results of performance demonstration with proto-type instrument aboard an aircraft.

On-orbit performance and level 1 data processing of TANSO-FTS and CAI on GOSAT

The Greenhouse gases Observing SATellite (GOSAT) monitors carbon dioxide (CO2) and methane (CH4) globally from space. It is a joint project of Japan Aerospace Exploration Agency (JAXA), Ministry of the Environment (MOE) and National Institute for Environmental Studies (NIES). GOSAT is placed in a sun-synchronous orbit of 666km and 12:48 local time, with an inclination angle of 98 deg. It was launched on January 23, 2009 from Tanegashima Space Center. There are two instruments on GOSAT. The Thermal And Near infrared Sensor for carbon Observation Fourier- Transform Spectrometer (TANSO-FTS) detects the Short wave infrared (SWIR) reflected on the earths surface as well as the thermal infrared (TIR) radiated from the ground and the atmosphere. TANSO-FTS is capable of detecting wide spectral coverage; three narrow bands (0.76, 1.6, and 2 μm) and a wide band (5.5-14.3 μm) with 0.27 cm-1 spectral resolution. The TANSO Cloud and Aerosol Imager (TANSO-CAI) is a radiometer of ultraviolet (UV), visible, and SWIR to correct cloud and aerosol interference. For three months after the launch, the on-orbit function and performance have been checked out. Now level 1A (raw interferogram) and level 2B (spectra) are now being processed and provided regularly with calibration data.

The pre-launch performance test and calibration results of Thermal And Near-infrared Sensor for carbon Observation (TANSO) on GOSAT

In order to characterize the pre-launch performance of Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) and Cloud and Aerosol Imager (TANSO-CAI) on the Green house gases Observing SATellite (GOSAT) under the environmental condition on orbit as well as in the laboratory, the Proto Flight Model (PFM) for TANSO-FTS and CAI have been developed. TANSO-FTS has three narrow bands of 0.76, 1.6 and 2.0 micron (Band 1, 2 and 3) with +/-2.5cm maximum optical path difference, and a wide band of 5.5 - 14.3 micron (band 4) in thermal near infrared region. TANSO-CAI is a radiometer for detection and correction of clouds and aerosol effects which might degrade the column concentration retrieval of CO2 and CH4. It has four spectral band regions; ultraviolet (UV), visible, near IR and SWIR. The basic character of TANSO-FTS and CAI, such as the Signal to Noise Ratio (SNR), the polarization sensitivity (PS), Instantaneous Field Of View (IFOV), spectral response, and also Instrumental Line Shape Function (ILSF) have been characterized by introducing the light emitted from the black body, halogen lamp and the tunable diode laser. In addition to these characterizations, micro vibration effect on orbit has been investigated on TANSO-FTS. There prelaunch test results demonstrated that TANSO will provide data for high accuracy CO2 and CH4 retrieval on orbit.

Airborne SWIR FTS for GOSAT validation and calibration

In order to validate and calibrate TANSO-FTS data of the GOSAT satellite, and also to develop the retrieval algorism for deriving the column density of CO2 and CH4 from spectra, the airborne SWIR (Short Wave Infrared Region) FTS (Fourier transform spectrometer) has been developed, characterized and demonstrated. This instrument is named as TSUKUBA model. The basically performance test of TSUKUBA model was carried out in our laboratory, and the measured modulation efficiencies are 70% (Band1), 85% (Band2) and 88% (Band3), respectively. The measured values of SNR with the equivalent black body temperature for 30% surface albedo are 190 (13050cm-1), 148 (6200cm-1), and 165 (5000cm-1) without polarization measurement. The measured values of full width at half maximum (FWHM) of instrumental line shape functions are 0.38cm-1, 0.26cm-1, 0.25 cm-1 of band 1, 2, and 3, respectively. This instrument is also able to measure the scene flux with P and S polarization, simultaneously, as TANSO-FTS SWIR measures. In 2007, the first and second flight campaigns were arranged and the sunlight reflected spectra over the earths surface was obtained. This instrument was mounted on high-altitude airplane with image motion compensator and damping platform, and flied over southern Australia and Siberia. The instrumental design and the results of performance tests as well as the flight campaign are presented.

Greenhouse Gases Observation from Space with TANSO-FTS on GOSAT

Thermal And Near infrared Sensor for carbon Observation (TANSO) Fourier-Transform Spectrometer (FTS) onboard the GOSAT monitors CO2 and CH4 globally from space. It has three narrow bands (0.76, 1.6, and 2 micron) and a wide band (5.5–14.3 micron) channel.

The performance test results for engineering model (EM) of thermal and near infrared sensor for carbon observation (TANSO) on GOSAT

In order to estimate and demonstrate the performance of Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) and Cloud and Aerosol Imager (TANSO-CAI) under the environmental condition on orbit, the Engineering Model (EM) for TANSO-FTS and CAI have been developed and demonstrated. The TANSO-FTS has three narrow bands detectable regions; 0.76, 1.6 and 2micrion (Band1, 2 and 3) with +/⊥2.5cm maximum optical path difference, and a wide band (5.5 − 14.3micron in thermal near infrared region. The TANSO-CAI is a radiometer of ultraviolet (UV), visible, and SWIR, which has 4 spectral band regions with 1 dimensional array CCDs. The initial performance tests have been carried out in the laboratory and the thermal vacuum chamber. The Signal to Noise Ratio (SNR), the polarization sensitivity (PS), Instantaneous Field Of View (IFOV) and response for FTS and CAI, and also the Instrumental Line Shape Function (ILSF) for FTS have been characterized in this test by introducing the light emitted from the black body, halogen lamp and the tunable diode laser. As a results of these experiments, it is appeared that the some modification of system for manufacturing the proto flight model (PFM) is required, and now in progressing. In addition to these characterizations, the newly developed tests, such as the stray light measurement and micro vibration test, are applied on TANSO-FTS to estimate the effect on orbit. These tests methods and results are presented in this paper.

The instrumentation and the contamination control activity of thermal and near-infrared sensor for carbon observation (TANSO) on GOSAT

The Greenhouse Gases Observing SATellite (GOSAT) is a satellite to monitor the carbon dioxide (CO2) and the methane (CH4) globally from orbit. Two instruments are accommodated on GOSAT. Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) detects the Short wave infrared (SWIR) reflected on the earths surface as well as the thermal infrared (TIR) radiated from the ground and the atmosphere. TANSO-FTS is capable of detecting wide spectral coverage, specifically, three narrow bands (0.76, 1.6, and 2 micron) and a wide band (5.5-14.3 micron) with 0.24 wavenumber spectral resolution. TANSO Cloud and Aerosol Imager (TANSO-CAI) is a radiometer of ultraviolet (UV), visible, and SWIR to correct cloud and aerosol interference. The contaminant deposition on the sensors significantly affects the sensing capability. So the spectroscopic contamination control over wide spectral range is required from the process of GOSAT development to on-orbit operation. The paper presents the instrument design of TANSO-FTS and TANSO-CAI, overview of GOSAT contamination control plan, results from spectral analysis of deposited outgas, test result of hydrazine (rocket and satellite thruster propellant) injection to an optical surface, as well as test result from contamination environment monitoring using a vacuum chamber and contamination witness plates.