JAXA EORC GOSAT retrieval
Last update: 2020/05/11
1. Introduction
TANSO-FTS simultaneously observes both reflected shortwave-infrared (SWIR) solar light and thermal infrared (TIR) emissions with a single FTS-mechanism. We use an entire TIR band to add only one piece of information in the troposphere. Assuming the CO2 and CH4 partial column-averaged dry air mole fractions of the two individual layers of LT and UT are constant, we retrieve the difference between the partial column-averaged dry mole fractions of the lower troposphere (LT) and upper troposphere (UT) by combining TIR and SWIR spectra data simultaneously, constraining accurate total column density. The pressure-height ranges of LT and UT are taken as 1 -0.6 and 0.6 -0.2 of the retrieved surface pressure, respectively.
The GHG long term trend viewer presents quick view and pick up data set of the target observation sites, where users are interested.
Most of the target observations requested by the RA researchers are not included in the list.
2. Data description
L1B version
About data category
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Airport (CONTRAIL)
The CONTRAIL (Comprehensive Observation Network for TRace gases by AIrLiner) project is being jointly conducted by NIES (National Institute for Environmental Studies), the MRI (Meteorological Research Institute), JAL (Japan Airlines), JAMCO (JAMCO Corporation) and JAL-F (JAL Foundation). The CONTRAIL Database contains all the CO2 data measured by CME, as well as the information from the aircraft data system (aircraft position, temperature, wind direction and wind speed). These data have been used for GOSAT validation. GOSAT has targeted airports in serve.
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Possible Emission Source
Possible large emission source site
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Megacity
Highly populated cities urban area
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Calibration
Vicarious calibration site
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TCCON (Total Carbon Column Observing Network)
The Total Carbon Column Observing Network (TCCON) is a network of ground-based Fourier Transform Spectrometers that record spectra of the sun in the near-infrared. From these spectra, accurate and precise column-averaged abundances of atmospheric constituents including CO2, CH4, N2O, HF, CO, H2O, and HDO, are retrieved.
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Island and Others
Targeting coasts and islands, while avoiding bays and channels in order to increase the yield rate of spectra.
About parameter
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yyyy/mm/dd and hh:mm:ss :
Observation time defined as the start time of the exposure.
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XCO2_apr:
A priori of the column averaged dry air mole fraction of CO2 calculated from CarbonTracker.
units = ppmv
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XCO2_tot:
Aerosol optical thickness at 0.72um is calculated from the retrieval state
units = ppmv
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XCO2_low:
Retrieved dry air mole fraction of CO2 in the lower troposphere defined as the partial layer from Psrf_ret up to 0.6 Psrf_ret.
units = ppmv
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XCO2_upp:
Retrieved dry air mole fraction of CO2 in the upper troposphere defined as the partial layer from 0.6 Psrf_ret up to 0.2 Psrf_ret.
units = ppmv
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XCH4_apr
A priori of the column averaged dry air mole fraction of CH4 calculated from CarbonTracker-CH4.
units = ppmv
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XCH4_tot
Retrieved column averaged dry air mole fraction of CH4.
units = ppmv
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XCH4_low
Retrieved dry air mole fraction of CH4 in the lower troposphere defined as the partial layer from Psrf_ret up to 0.6 Psrf_ret.
units = ppmv
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XCH4_upp
Retrieved dry air mole fraction of CH4 in the upper troposphere defined as the partial layer from 0.6 Psrf_ret up to 0.2 Psrf_ret.
units = ppmv
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Psrf_apr
A priori of the surface pressure calculated from NCEP Reanalysis 2.
units = hPa
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Psrf_ret
Retrieved surface pressure.
units = ppmv
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AOT_076
Retrieved aerosol optical thickness at 0.76 µm.
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AOT_160
Retrieved aerosol optical thickness at 1.6 µm.
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AOT_206
Retrieved aerosol optical thickness at 2.06 µm.
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SIF
Retrieved solar-induces fluorescence which is assumed to be constant in the O2 A band.
units = 10-9 W/cm2/sr/cm-1
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CLFLG
Cloud flag visually judged from onboard camera images.
0 = clear
1 = cloudy
-1 = not available
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latitude and longitude
Observation location.
units = degree
About data extraction
In order to use long term trend data of the point of interest, the viewer pick up data within the circle of 10km radius.
But the following adjacent site, the viewer pick up within the circle of 1km or 2km radius.
[circle of 1km radius]
Pasadena_downtown
Caltech_USA
Osaka3, Osaka4
Bakersfield4 - 6
Boston4, Boston5, Greece4, Greece5
[circle of 2km radius]
JPL
Tokyo6, 8, 11 - 13
Osaka5
Bakersfield2, Bakersfield3
Aliso_Canyon2 - 4
Namibia1 - 3
Antarctica1 - 4
Beijing1 - 16
Shanghai1 - 13
Delhi1 - 16
Dhaka1 - 16
MexicoCity1 - 16
Istanbul1 - 16
Cairo1 - 15
CebuIsland1, 2
Sacramento(Rice Field), Sacramento(CA Capitol)
Karachi1 - 16
The primary pointing system, which had been used between launch and Dec. 2014, larger pointing offset of about 5km.
Therefore, some cases include nearby target points.
3. Citation
Algorithm:
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Kikuchi, N., Kuze, A., Kataoka, F., Shiomi, K., Hashimoto, M., Suto, H., et al. (2017), Three-dimensional distribution of greenhouse gas concentrations over megacities observed by GOSAT, AGU fall meeting.
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The SWIR part of the algorithm is described by Kikuchi et al. (2016):
Kikuchi, N., Y. Yoshida, O. Uchino, J. Morino, and T. Yokota: An advanced retrieval algorithm for greenhouse gases using polarization information measured by GOSAT TANSO-FTS SWIR I: Simulation study, J. Geophys. Res., 121, 21, 13129-13157, doi:10.1002/2015JD024720, 2016
Ancillary data
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NCEP_Reanalysis 2 data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA, from their Web site at https://www.esrl.noaa.gov/psd/
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CarbonTracker results provided by NOAA ESRL, Boulder, Colorado, USA from the website at http://carbontracker.noaa.gov.
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CarbonTracker-CH4 results provided by NOAA ESRL, Boulder, Colorado, USA from the website at http://www.esrl.noaa.gov/gmd/ccgg/carbontracker-ch4/.
4. Links
5. Acknowledgments
GHG Long term trend viewer was developed by JAXA/EORC. We would like to thank NIES GOSAT project members, and JAXA GOSAT project members.