Calibration of operational GOSAT Level 1 products

Shiomi, Kei; Kina, Tomoko; Kawakami, S.; Takeshima, T.

doi:10.1117/12.865459

Cited by 3 publications

(4 citation statements)

References 5 publications

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“…The influence of the ILS is primarily reflected in two aspects: modulation loss and phase error: modulation loss causes the broadening of the ILS, and phase error affects the symmetry of the ILS. This paper aims to describe the two main characteristics that affect the ILS by introducing a Gaussian function model, as shown in Equation (18).…”

Section: On-orbit Ils Iterative Model Algorithmmentioning

confidence: 99%

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Research on calculation method of on-orbit instrumental line shape function for the Greenhouse Gases Monitoring Instrument on the GaoFen-5B satellite

Han,

Shi,

et al. 2024

Preprint

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The Greenhouse Gases Monitoring Instrument is based on the spectroscopic principle of spatial heterodyne spectroscopy technology and has the characteristics of no moving parts, hyperspectral resolution, and large luminous flux. The instrumental line shape function is one of the important parameters characterizing the characteristics of the instrument and plays a vital role in the system error analysis of instrument measurement. To accurately obtain the instrumental line shape function of the spatial heterodyne spectrometer during on-orbit period and improve the accuracy of gas concentration retrieval, this paper develops a method to model and characterize the characteristics of the instrumental line shape function, including modulation loss and phase error. Utilizes the stability of solar observation spectrum wavelength and is not influenced by additional conditions to update the instrument line function. The Kurucz solar spectrum model used as the theoretical reference spectrum, selects the characteristic spectral lines corresponding to the measured solar calibration spectrum and the reference spectrum in the 1.568~1.583 μm band, and adjusts the instrumental line shape function model parameters, iterates the characteristic spectral lines residual, and calculates the instrumental line shape function variations. The updated instrumental line shape function has increased the average relative deviation between the theoretical simulated and measured solar spectrum from 1.83% to 0.756%, and the average relative deviation between the nadir observation spectrum and the simulated spectrum has increased from 7.049% to 2.106%. The findings demonstrate that updating the instrumental line shape function mitigates the impact of variations in the spectrometer's instrumental line shape due to alterations in the orbital environment. This offers a dependable reference for both the enhancement and oversight of the spectrometer's instrumental line shape function, along with the investigation of shifts in instrument parameters.

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Section: On-orbit Ils Iterative Model Algorithmmentioning

confidence: 99%

“…(7) Calculate the corresponding model parameters , , a   when the evaluation function 2  is the smallest. Then, obtain the final ILS data according to Equation (18). The average relative deviation is used as the evaluation function, as shown in the Equation ( 19), as follows:…”

Section: The Ils Modulation Term Error Correctionmentioning

confidence: 99%

Research on calculation method of on-orbit instrumental line shape function for the Greenhouse Gases Monitoring Instrument on the GaoFen-5B satellite

Han,

Shi,

et al. 2024

Preprint

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“…Kuze et al [20] have also described the details of the two TANSO instruments, as well as the data processing from raw interferogram to spectral radiance. In the present study, the calibrated spectral radiances in the TIR region (band 4) are used [28]. Fig.…”

Section: Gosat Measurementsmentioning

confidence: 99%

Retrievals of Total and Tropospheric Ozone From GOSAT Thermal Infrared Spectral Radiances

Ohyama

Kawakami

Shiomi

et al. 2012

IEEE Trans. Geosci. Remote Sensing

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Total and tropospheric ozone columns have been retrieved from thermal infrared spectral radiances recorded with the Thermal And Near infrared Sensor for carbon ObservationFourier Transform Spectrometer (TANSO-FTS), which is onboard the Greenhouse gases Observing SATellite launched on January 23, 2009. We present ozone retrievals that were performed over about two years of observations (during the period from April 2009 to December 2010) over four climatically distinct regions (the Sapporo, Tsukuba, Naha, and Syowa sites). Annual variations of the total and tropospheric ozone columns over the four sites were derived. We compare TANSO-FTS total ozone columns with ground-based data from the Dobson spectrophotometer, and the seasonal trends and patterns of the retrieved total ozone are consistent with those of Dobson measurements. The TANSO-FTS total ozone columns are in good agreement with the Dobson data, with a correlation coefficient of about 0.98. On average, TANSO-FTS total ozone retrievals exhibit a positive bias of 8.8 DU (3.0%) with a root-mean-square difference of 10.9 DU (4.1%) compared to the Dobson measurements. Comparisons of the TANSO-FTS tropospheric ozone columns to ozonesondes available from the four sites have been performed. The TANSO-FTS tropospheric ozone columns compare well with the ozonesonde measurements, with correlation coefficients of 0.96 and 0.92 for the surface-tropopause and surface-6 km partial columns, respectively. Average differences of 0.7 ± 4.2 DU (2.5% ± 12.8%) and −0.7 ± 2.2 DU(−3.0% ± 12.2%) are found for the surface-tropopause and surface-6 km partial columns, respectively.

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“…This involves measuring the ILSF by selecting prominent gas absorption lines or laser wavelengths within the working spectral range. For on-orbit ILSF determination, laser diodes are commonly chosen as light sources [18][19][20], sharing the same principles as tunable lasers. Another option is to use the solar spectrum, although adjustments to parameters such as the distance from the Sun to the Earth and solar activity cycles are necessary [21].…”

Section: Introductionmentioning

confidence: 99%

Research on Calculation Method of On-Orbit Instrumental Line Shape Function for the Greenhouse Gases Monitoring Instrument on the GaoFen-5B Satellite

Han,

Shi,

Luo

et al. 2024

Remote Sensing

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The Greenhouse Gases Monitoring Instrument is based on the spectroscopic principle of spatial heterodyne spectroscopy technology and has the characteristics of no moving parts, a hyperspectral resolution, and a large luminous flux. The instrumental line shape function is one of the most important parameters characterizing the features of the instrument, and it plays a vital role in the system error analysis of the instrument’s measurements. To accurately obtain the instrumental line shape function of a spatial heterodyne spectrometer during the on-orbit period and improve the accuracy of gas concentration retrieval, this study develops a method to model and characterize the characteristics of the instrumental line shape function, including modulation loss and phase error. This study employs the solar calibration spectrum in the 1.568–1.583 μm bands to conduct iterative calculations of the instrumental line shape function error model. After the instrumental line function is updated, the average relative deviation is reduced from 1.83% to 0.756% between the theoretical and measured solar spectra. Additionally, the average relative deviation is reduced from 7.049% to 2.106% between the GMI nadir and theoretical nadir spectra. The findings demonstrate that updating the instrumental line shape function mitigates the impact of variations in the spectrometer’s instrumental line shape due to alterations in the orbital environment. This study offers a dependable reference for both the enhancement and oversight of a spectrometer’s instrumental line shape function, along with an investigation of shifts in instrument parameters.

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Calibration of operational GOSAT Level 1 products

Cited by 3 publications

References 5 publications

Research on calculation method of on-orbit instrumental line shape function for the Greenhouse Gases Monitoring Instrument on the GaoFen-5B satellite

Research on calculation method of on-orbit instrumental line shape function for the Greenhouse Gases Monitoring Instrument on the GaoFen-5B satellite

Retrievals of Total and Tropospheric Ozone From GOSAT Thermal Infrared Spectral Radiances

Research on Calculation Method of On-Orbit Instrumental Line Shape Function for the Greenhouse Gases Monitoring Instrument on the GaoFen-5B Satellite

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