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Tsuneo Matsunaga
2024 Volume 44 Issue 2 Pages
90-95
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: May 31, 2024
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Satellite remote sensing of greenhouse gases (GHGs), such as carbon dioxide and methane, is one of most rapidly growing fields of remote sensing technology. The pioneering measurements by SCIAMACHY onboard European ENVISAT satellite and Japanese GOSAT series have paved the way to the commercial satellites for GHGs measurements and the use of satellite data in climate change policy relevant applications including the verifications of national GHGs emission inventories. This manuscript will give an overview of satellite remote sensing projects for GHGs starting from early 2000's and provide some insights into future missions.
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Hiroshi Tanimoto, Tsuneo Matsunaga
2024 Volume 44 Issue 2 Pages
96-101
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: May 29, 2024
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With the TANSO-3 sensor onboard, the Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW) greenhouse gas (GHG) observing mission will make the first global, space-based observations of the column-averaged carbon dioxide (CO2) and methane (CH4) dry air mole fraction (XCO2 and XCH4, respectively) and vertical column density of tropospheric nitrogen dioxide (NO2) in the Earth’s atmosphere at a horizontal/spatial resolution of less than or equal to 3 km by the single satellite platform. The objectives of the GOSAT-GW’s GHG observing mission include (1) monitoring of whole atmosphere global-mean concentrations of GHGs, (2) verification of national (or country-specific) anthropogenic emissions inventory of GHGs, and (3) detection of GHGs emissions from large emission sources, such as megacities, power plants, and permafrost. With a nominal lifetime of 7 years, the GOSAT-GW will provide space-based constraints on the anthropogenic GHG emissions, contributing to the mitigation of climate change, in particular, supporting the Global Stocktake (GST) mechanism, a key element in the Paris Agreement.
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Yasushi Kojima, Yoshihiko Okamura, Michito Sakai, Takeshi Miura, Hiroy ...
2024 Volume 44 Issue 2 Pages
102-109
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: May 29, 2024
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Hisashi Yashiro, Takafumi Sugita, Tazu Saeki, Satoshi Kikuchi, Yu Some ...
2024 Volume 44 Issue 2 Pages
110-119
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: May 31, 2024
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Data obtained by the Total Anthropogenic and Natural emissions mapping SpectrOmeter-3 (TANSO-3) on board the Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW) will be processed in stages and distributed to users as TANSO-3 products. In order to start data processing immediately after the launch of GOSAT-GW, ground systems are currently being developed by the Japan Aerospace Exploration Agency (JAXA) and the National Institute for Environmental Studies (NIES). NIES is responsible for making Level 2 products from Level 1 products from JAXA, and for storing these products and delivering them to users. The NIES ground system consists of three systems: 1) the GOSAT 3rd-generation Data Processing/operating System (G3DPS) for product handling, storage and distribution, and for arranging observation requests; 2) the GOSAT-GW NO2 Data Processing System (GNDPS), which is responsible for processing Level 2 product (NO2) on the commercial cloud service; and 3) the GOSAT Operational and research Computing Facility (GOCF), which provides large-scale computing resources for Level 2 product (greenhouse gas, GHG) processing. In the future, TANSO-3 products will be available to general users through the GOSAT-GW TANSO-3 Product Archive (G3PA) website constructed on G3DPS. Dealing with the explosive increase in computational workload due to the increase in observation points from TANSO-3 for calculating column-averaged dry-air mole fractions of carbon dioxide (XCO2) and methane (XCH4) is one of the challenges for the NIES ground system and retrieval algorithms. At the time of writing, in FY2023, ground system tests are underway in coordination with the optimization of Level 2 product processing programs.
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Yu Someya, Hisashi Yashiro, Yukio Yoshida
2024 Volume 44 Issue 2 Pages
120-126
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: June 04, 2024
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The Global Observation SATellite for Greenhouse gases and Water cycle (GOSAT-GW) is planned to be launched in FY2024. Total Anthropogenic and Natural emissions mapping SpectrOmeter-3 (TANSO-3) on GOSAT-GW has three bands in the range from visible to shortwave infrared spectral regions, including the carbon dioxide (CO2) and methane (CH4) absorption bands. The GOSAT-GW project will provide column-averaged dry air mole fractions of CO2 and CH4 (XCO2 and XCH4, respectively) estimated from the observed spectra as the TANSO-3 Level 2 greenhouse gas (L2GHG) product. This product is processed by the algorithm called GOsat Retrieval ALgorithm (GORAL), which includes two different greenhouse retrieval techniques; the full physics and proxy methods. The full physics method simultaneously estimates XCO2 and XCH4 with explicit consideration of multiple scattering by aerosols in the radiative transfer calculations. The proxy method estimates XCH4 utilizing CO2 as a proxy to resolve contamination by multiple scattering using the close absorption bands of CO2 and CH4 near 1.6 μm.
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Tamaki Fujinawa, Hyunkwang Lim, Tomohiro Sato, Takashi Sekiya, Yousuke ...
2024 Volume 44 Issue 2 Pages
127-134
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: June 06, 2024
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Hirofumi Ohyama, Satoshi Inomata, Isamu Morino, Matthias Max Frey, Tos ...
2024 Volume 44 Issue 2 Pages
135-144
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: June 06, 2024
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The Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW) will be launched in the Japanese fiscal year 2024. The Total Anthropogenic and Natural emissions mapping SpectrOmeter-3 (TANSO-3), one of the instruments onboard GOSAT-GW, is an imaging grating spectrometer that measures backscattered sunlight, from which the column-averaged dry-air mole fractions of carbon dioxide (XCO2) and methane (XCH4) and the total and tropospheric vertical column densities (VCDs) of nitrogen dioxide (NO2) will be derived (TANSO-3 Level 2 products). TANSO-3 will have two observation modes: Wide Mode, with a ~900 km swath width and a ~10 km footprint size; and Focus Mode, with ~90 km × 90 km observation areas and a < 3 km footprint size. The TANSO-3 Level 2 products will be validated primarily with data from global ground-based remote sensing networks. Total Carbon Column Observing Network (TCCON) and COllaborative Carbon Column Observing Network (COCCON) data will be used to validate XCO2 and XCH4, while Pandonia Global Network (PGN) and Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) data will be used for NO2 VCD. Airborne in situ measurements, satellite measurements other than GOSAT-GW, and simulated concentration fields from atmospheric transport models will complement the ground-based data. In order to validate the Focus Mode data in urban areas, it is crucial to evaluate small-scale spatial gradients in XCO2, XCH4, and NO2 VCD. Therefore, we are developing an urban operational observation network in the Tokyo metropolitan area, Japan, by deploying co-located EM27/SUN (COCCON instruments) and Pandora (PGN instruments) spectrometers.
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Jagat S. H. Bisht, Prabir K. Patra, Masayuki Takigawa, Yugo Kanaya, Ma ...
2024 Volume 44 Issue 2 Pages
145-155
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: June 04, 2024
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This study simulated carbon dioxide (CO2) using regional Weather Research and Forecasting coupled with greenhouse gas modules (WRF-GHG) based on a central grid over Japan and at 27 km spatial resolution for the year 2019. We analyzed the Total Carbon Column Observing Network (TCCON) total column of CO2 dry air mole fraction (XCO2) using both global and regional modeling frameworks. XCO2 was found to be significantly influenced by the CO2 concentration at higher atmospheric pressure levels (> 400 hPa). We made use of the global Model for Interdisciplinary Research on Climate, version 4.0 based Atmospheric Chemistry-Transport model (MIROC4-ACTM) with a well-resolved stratosphere to better represent variabilities in XCO2. We analyzed observations from three TCCON sites over Japan: Saga (130.3oE, 33.2oN), Tsukuba (140.1oE, 36.0oN), and Rikubetsu (143.7oE, 43.4oN), finding that correlation improved between observed and model-simulated XCO2 profiles by using CO2 concentration profile data produced by a hybrid model that combines WRF-GHG and MIROC4-ACTM; we used MIROC4-ACTM CO2 concentrations at higher altitudes (< 400 hPa) with the WRF-GHG CO2 output at lower altitudes. The correlation improvement between observed and simulated XCO2 concentrations was most prominent over Saga (~35 %), which is near high CO2 emission/sink regions such as China, Korea and southeast Asia. WRF-GHG simulations show a significant underestimation of XCO2 over Saga during April and May of 2019. An analysis of WRF-GHG CO2 spatial plots shows a tropopause fold that brings more depleted CO2 air to Saga through stratosphere-troposphere exchange (STE) than suggested by the observations. The analysis was also conducted with XCO2 data from Orbiting Carbon Observatory (OCO)-2 satellite observations, WRF-GHG, MIROC4-ACTM, and the hybrid model for the initial four and six months. The findings indicate that during the initial six months, WRF-GHG slightly underperformed compared to MIROC4-ACTM XCO2. This suggests the need for precise tuning of the land biosphere in WRF-GHG, as the inclusion of the active land-biospheric period appears to deteriorate XCO2 calculations from WRF-GHG.
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Masahiro Yamaguchi, Yugo Kanaya, Masayuki Takigawa, Jagat S. H. Bisht, ...
2024 Volume 44 Issue 2 Pages
156-165
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: June 04, 2024
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A method based on the divergence theorem was developed to estimate emissions from high-frequency and high-horizontal-resolution satellite observations of atmospheric trace gases (NO2 and CO2), by accounting for the expected performance of the upcoming TANSO-3 / Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW). Pseudo satellite observations to which the divergence method was applied were constructed from atmospheric chemistry transport model simulations over the Kanto region with a 1-km horizontal resolution. Observational errors were then added as normal distributions with the standard deviations of 1.8 ppm for CO2 total column dry-air mole fraction (XCO2) and 3×1015 molecules/cm2 for NO2 tropospheric column density (NO2VCD). The results showed that our central emission estimates for the Kashima Industrial Zone were within 10-24 % of the true values for CO2 and NOX, confirming the performance of the method. Uncertainties in the emission estimates propagated by observational errors (noise) were evaluated to be ±32 % and ±2 % for CO2 and NOX emissions of 16.6 MtCO2/year and 25 ktNOX/year, respectively, after averaging over 31 ideal observations, expected to occur within a 3-month period at best for GOSAT-GW.
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Hibiki M. Noda
2024 Volume 44 Issue 2 Pages
166-169
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: June 06, 2024
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Tomoki Morozumi, Tomomichi Kato, Hideki Kobayashi, Hibiki Noda, Tsuneo ...
2024 Volume 44 Issue 2 Pages
170-176
Published: June 18, 2024
Released on J-STAGE: September 20, 2024
Advance online publication: May 29, 2024
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