Validation Plan(of GOSAT TANSO Standard Products)
Isamu Morino
National Institute for Environmental Studies (NIES),
Tsukuba, Ibaraki 305‐8506, Japan
Workshop on
the Data Utilization of Greenhouse gases Observing SATellite (GOSAT) "IBUKI"
Tokyo, November 5, 2008

Definition of validation
Validation
to evaluate uncertainties of GOSAT products withother data of less uncertainties acquired independently
Comparison
to evaluate GOSAT products with observation data withequivalent uncertainties or data estimated bysimulation models
Calibration
to evaluate L1 product which is performed mainly byJAXAUncertainty={(accuracy)2 + (precision))2}1/2

Basic Concept of GOSAT Validation¾ The priorities of standard product validation and comparison
have been set as follows:(1) L2 SWIR CO2 and CH4 column abundances(2) L2 TIR CO2 vertical profile of concentration(3) Global distributions of L3 SWIR CO2 and CH4 columnabundances(4) Global distribution of L4A CO2 flux(5) Global distribution of L4B CO2 concentration

Strategy for validation ofGOSAT CO2 and CH4 column abundances¾ Requirement for observation equipments
9 Well established observation technology
9 Small uncertainty; CO2 less than 1%（0.3% preferable) , CH4 less than 2%¾ Measurement technique to validate these products
9 Absorption technique of solar direct radiation by ground‐based high ‐resolution FTS (0.05‐0.015 cm‐1) and mobile FTS (around 0.2 cm‐1)
9 Aircraft in situ measurement （e.g. JAL project data）

To validate TIR products, vertical profiles of temperature, pressure, and water
vapor obtained by Rawin Sonde are useful.

Methodology of validation of L2 products¾ Collect data at various conditions
9 Albedo：grassland, forest, desert, snow surface, urban, sea surface
9 Terrain：flat or complex
9 Aerosol：sea salt, dust, artificial sulfuric acid, black carbon, organic carbon
9 Cirrus：thick or thin
9 Water vapor ：high or low
Continuously observing sites (ground‐based high‐resolution FTS: about 10 sites, JALproject: 10 airports) for validation (under consideration)※Considering points: required quality level and cost effective¾ Set up necessary instruments at continuously observing sites(e.g. FTS, lidar and sky radiometer)¾ Evaluation of spatial and temporal characteristics at each FTS site
→ Identify the accuracy of GOSAT L2 products(It will take much time for evaluating the bias. 3 months for Lauder? )→ Grouping (cirrus, aerosol, water vapor, albedo and etc.)¾ Other methods
e.g. Trajectory analysis, Regional CO2 forward modelError factors in deriving XCO2 and XCH4Priority

Error factor

Methodology**

Characteristics of TANSO FTS(e.g. SNR)

Calibration**Aerosol

Validation*

Thin cirrus

Validation*

Surface pressure (elevation)

Validation*

Profiles of P, T and R.H.

Validation*

Absorption line

Algorithm*

Fraunhofer line

Algorithm*

Surface albedo(sunglint reflectance)

Validation**: the top priority, *: the second priority.

Schematic illustration of validation experiments

Source: GOSAT pamphlet

The uncertainty of the ground based high resolution
FTS（Park Falls）
Washenfelder, R. A., et al. (2006), J. Geophys. Res.,
111, D22305, doi:10.1029/2006JD007154.

¾ The precision of FTS column CO2
Clear day → about 0.1%
Partly cloudy day → about 0.2%¾ The bias of FTS column CO2 compared to integrated
aircraft profiles
less than 2%¾ The uncertainty of FTS column average CO2 VMR
after calibration
about 0.3% (±1.1 ppmv) at SZA less than 60 deg
The high resolution FTS is useful for GOSAT validation.
It is necessary to calibrate the FTS at validation sites.

TCCON is indispensable for GOSAT validation
EurekaPoker Flat

Park Falls

Ny Alesund

BremenBialystok

Orleans

Moshiri

GarmischLamontIzana

Ascension
IslandTsukuba

DarwinWollongong
Lauder：will be used for initial validation

TCCON :Total Carbon Column Network（http://www.tccon.caltech.edu/index.html）

Observation plan of cloud and aerosol parameters
at some potential FTS sites for GOSAT validation
Instrum.

FTS

LidarSkyRadiometerSun
Photometer

Tsukuba

Bruker 120HR(NIES)

Observed
by NIES & MRI

Observedby MRI

None

Moshiri

Bruker 120HR(Nagoya U.)

To be installed

To be installed(NIES’s)

None

Lauder

Bruker 120HR(NIWA)

To be upgraded(MRI & NIES)None

CSD Middleton
SP02 (ABM)

BremenBruker 125 HR(U. Bremen)

Seeking the fundto install

To be installed(NIES’s)

None

DarwinBruker 125 HR

Small power lidar(ARM site)

None

Cimel (ARMsite )Siteetc.

Lidar : two-wavelength polarization lidar

The site conditions of Tsukuba FTS

NIES at Tsukuba

The site conditions of Tsukuba FTS
Rawin sonde
Ozone sonde

200m tall tower

Millimeterwave
radiometer

FTS (Bruker 120HR)

Aerosol lidar
Ozone lidar

Ground‐based NIR FTS at Tsukuba

Dome with solar
tracking system

・ Observation site

National Institute for Environmental Studies (NIES),Tsukuba, Japan(Latitude 36.1°N, Longitude 140.1°E, Altitude 31 m)
・ FTS: Bruker IFS 120 HR

Beam splitter: CaF2Detector: InSb (1,800–10,500 cm‐1)
Si diode (9,200–14,000 cm‐1)
Instrument resolution: 0.05–0.0035 cm‐1
Observation time: ~10 min
・ In 2001, measurements of atmospheric constituents

related with the destruction of the ozone layer
were started in MIR region.

・ In 2004, optical components of the FTS werereplaced for measuring greenhouse gases such as
CO2 and CH4 in NIR: optical filters,
CaF2 beam splitter, and InSb detector.
However, in the present,measurements with the NDSC #1, #2, and #3
optical filters are also in operation.
※NIES NIR FTS will be joined to TCCON

FTS in observation

Airborne observation data is very useful for GOSAT validation

JAL flight routes of CO2 observation and destination airport.
The numbers indicate the number of vertical profiles over each airport
from November 2005 to April 2007.
Machida, Matsueda and Sawa, 2007(IGAC Newsletter)

Vertical CO2 profiles obtained by CME on board aircraft (JAL)around Narita and Jakarta airport

NaritaSimilar profiles ： Nagoya, Kansai

JakartaSimilar profiles：Sydney, LA

Machida, Matsueda and Sawa, 2007 （IGAC Newsletter)

Data for estimation of XCO220

Altitude (km)Tropopause
1510JAL data5PBL

0370

375

380

CO2 (ppm)

385

390

・in situ CO2 data obtained by descending
JAL aircraft (1,500~12,418 m)( Narita airport 2006/10/26)
・Tateno rawin sonde data
PBL height : 1,000 m
Tropopause height : 17,227 m
・CO2 data from ground to PBL
in situ data of MRI/JMA tower (200m)(by Machida)・CO2 data above 20km
assumed nearly equal to the averagevalue in troposphere 5 years ago(371.7 ppm)

XCO2=380.079 ppm

Validation for GOSAT sunglint observation
Observation area: Sagami‐bay (35.0‐35.1ºN, 139.2‐139.4ºE)
Sampling altitude: 0.5, 1, 1.5, 2, 3, 4, 5.5, 7 km
Sampling method: Flask sampling → Nadir
Observation schedule : every 2 weeks

Tsukuba
130 kmSagami-bay

Beechcraft 200T

[T. Machida, NIES]

Validation of aerosol and cirrus cloud¾ Error factors to the column abundance
9 Aerosol and thin cirrus cloud
9 It is necessary to observe these factors with CO2 and CH4 column
abundances at the same time.
¾ Lidar• Derive the vertical distributions of aerosols and thin cirrus clouds with a range
resolution of 15 m.
• Derive depolarization ratio with high accuracy, and discriminate liquid andsolid particles.
¾ Skyradiometer• Derive optical depth, particle size distribution and phase function withmeasurements of direct solar radiation and forward scattering.
• Derive Single‐scattering albedo and phase function with these parameters.
To validate TANSO‐CAI, measurements by lidar and skyradiometer are useful.
SKYNET and AERONET data are also important for GOSAT validation.

Summary• Ground‐based high resolution FTS data are indispensable forvalidation of CO2 and CH4 column abundances retrieved fromGOSAT data.
• Airborne in‐situ measurement data are also important forvalidation of column abundances and vertical profiles of CO2and CH4.
• Aerosol and thin cirrus cloud measurements at FTS sites arenecessary to validate and improve GOSAT CO2 and CH4column abundances.