P1253296667KjUQg

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GOSAT Mission Overview Takashi
Hamazaki Project Manager Greenhouse Gases
Observing Satellite (GOSAT) Japan Aerospace
Exploration Agency (JAXA)
Presented to Carbon from Space _at_Frascati, Italy
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GOSAT Mission Objectives

• GOSAT has two major mission objectives
• (1)To contribute to the environmental policy
  development.
• - by monitoring the global distribution of
  GHG(CO2 and CH4)
• - by estimating the source and sink of GHG at
  sub-continental scale.
• (2)To contribute to the advancement of earth
  observation technologies.
• - by developing Short Wave and Thermal Infrared
  Fourier Transform Spectrometer
• - by developing highly reliable and robust
  satellite system

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GOSAT Mission Targets

• To observe CO2 and CH4 columnar density
• - at 100-1000km spatial scale (with pointing
  mechanical)
• - with relative accuracy of 1 for CO2(4ppmv, 3
  month average) and 2 for CH4.
• - with Shortwave and Thermal Infrared FTS
• - during the Kyoto Protocol's first commitment
  period (2008 to 2012).
• (2) To reduce sub-continental scale CO2 annual
  flux estimation errors by half
• -0.54GtC/yr?0.27GtC/yr

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GHG Observing Points
Ground Stations (current)
From Space (GOSAT)
(By WMO WDCGG)
Over 100,000 points per 3days Global and
frequent observation with an single instrument

• 274 ground stations in the world.
• The observing data from these stations is
  distributed from WDCGG of WMO
• The number of stations is limited, and they
  exists unevenly in the world.
• WDCGG World Data Center for Greenhouse Gases
• WMO World Meteorological Organization

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Organization

• GOSAT is the joint project of JAXA, MOE
  (Ministry of the Environment) and NIES (National
  Institute for Environmental Studies).

JAXA
MOE

• Sensor development
• Satellite development
• H-IIA launch
• Satellite operation
• Data acquisition
• Calibration

• Sensor development
• (Funding Support)
• Date Policy

• Algorithms development
• Data use for science
• Validation

NIES
GOSAT Science Team

• Scientific Advice
• Data use for science

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GOSAT Satellite and Launcher
Size Main body 2.6 x 2.4 x 3.7 m Wingspan 14m
Mass Total 1650kg
Power Total 4040W
Lifetime 5 years 5 years
Orbit Sun Synchronous Orbit Sun Synchronous Orbit
Orbit Local time 1300015
Orbit Altitude 666km
Orbit Inclination 98deg
Orbit Re-visit 3 days
Launch Vehicle H-IIA
Launch Schedule Aug.2008
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GOSAT Sensor Characteristics
Greenhouse Gases Observing Sensor Clouds and Aerosol Sensor

Size 1.21.10.7m 0.50.40.5m
Mass 250kg 40kg
Power 310W 100W
FOV 1000km(mechanical scan) 1000km
IFOV 10km 0.5km-1km
Resolution 0.2-0.5(Band1)cm-1 20-130 nm
SNR 300 200
Channel ch10.75-0.78µm/ ch2 1.56-1.72µm ch31.92-2.08µm/ ch45.5-14.3µm ch10.38µm/ ch20.67µm ch30.87µm/ ch41.61µm

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Pointing Pattern
5 types of Cross Track Pointing
Patterns (1,3,5,7,and 9 Observation points per
one cross track)
GPS Satellite
GPS Antenna
Star Tracker
GOSAT
Flight Direction
Scan Points Mesh
1 789km
3 263km
5 158km
7 113km
9 88km
88 789 km
Along Track
Cross Track
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Bread Board Model
Detectors Filters
Pre Amplifier
FOV camera
Input
Bread Board Model
Laser Diode 1.31 µm
FTS swing arm
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Airplane and Airship Campaign with BBM
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GOSAT Data Analysis

• G. Inoue, T.Yokota, et al.
• GOSAT research team
• National Institute for Environmental Studies
• e-mail inouegen_at_nies.go.jp

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Nadir looking of solar scattered light with
three bands
H2O
O2-A
CO2
CO2
CO2
CH4
(1) 0.76 µm band (2) 1.6 µm band
(3) 2.0 µm band
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Retrieval under existence of cirrus/aerosol

• Unknown parameters
• Optical thickness
• Surface reflectance
• Height distribution

• Improvement of SNR
• Increase of useful data

cirrus
aerosols
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Stepwise retrieval from three bands

• Step 1 Cirrus optical thickness (t) estimation
  from H2O saturated area of the 2.0 µm band
• Step 2 Estimation of cloud height distribution
  (h) and ground surface albedo (a) from
• 0.76 µm (O2-A) band
• Step 3 Simultaneous retrieval of column
  densities of the three gases, cirrus optical
  thickness (t), and ground surface albedo (a)
  from
• 1.6 µm and 2.0 µm bands

• With non-negative value constraint adding to
  (Rodgers (2000) p.85)

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Validation strategy of GOSAT

• G. Inoue, T.Yokota, et al.
• GOSAT project team
• National Institute for Environmental Studies
• e-mail inouegen_at_nies.go.jp

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GOSAT
Aircraft (BBM on board)
In Situ on Aircraft
Ground in situ
Ground HR FTS
Column observation with less disturbances at high
resolution
Simulation experiment but not frequent
Ground point data but continuous
Vertical profile but over large cities
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In Situ on JAL passengers aircraft
per Month
Continuous
Flask sampling
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Ground and Aircraft Observation Sites
70
1,000km
Nayabrsk
Igrim
Surgut(An-24)
Parabel
60
Tomsk(An-2)
Kachkanar
Beryozovayarechka
Demyanskoe
Novosibirsk (An-30)
50
Omsk
60
Yakutsk
80
70
Smolenskoe
90
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Frequency
Vertical distribution
In situ
column
Precision
Absolute
Relative
GOSAT
Tower
Ground FTS
JAL
BBM on aircraft
JAL
GOSAT
Light aircraft
Flask sampling
OCO
Light aircraft
Tower
BBM on aircraft
Ground FTS
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Conclusion

• GOSAT sensor characteristics
• High throughput FTS
• SWIR and TIR channels
• CO2 and CH4 columnar density
• Night-time observation, Altitude distribution
• Fully redundant pointing mechanism
• Observation mesh is selectable.( 88-789km )
• Fixed site pointing, Sun glint observation
• Cloud and Aerosol sensor
• Secondary sensor for error correction
• Sensor aircraft and airship demonstrations are
  underway.
• Cooperation with NASA/OCO in the field of Cal/Val
  is under discussion.
• Cooperation with European Scientists is expected.
• GOSAT project is making solid progress.