CH4 and CO2 from space :The SCIAMACHY, GOSAT and Precursor S5 missions

Guerlet, Schepers, Galli, Butz1, Frankenberg2, Hasekamp, Landgraf, Houweling, Ilse Aben

SRON Netherlands Institute for Space Research, Utrecht, The Netherlands1Institute for Meteorology and Climate research, Karlsruhe Institute Technology, Germany

2Jet Propulsion Laboratory, USA

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Global surface network high accuracy, but limited in coverage (e.g. Tropics) to accurately quantify contribution of natural and anthropogenic emissions.

Satellite observations are complementary.Less accurate but with global coverage

But requirements very demanding (sub) % level

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Blackbody curves, solar vs. earth radiationSWIR vs TIR measurements (passive)

SWIR TIR

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Blackbody curves, solar vs. earth radiation

SWIR CH4 (and CO2) missions :

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SCIAMACHY on ENVISAT2002 – 2013/2014

CH4 (and CO2)and many other species

TROPOMI on Precursor Sentinel-52014 – 2021, Sentinel-5 2020 - …CH4 and many other species

GOSAT2009 - …

CH4 and CO2

OCO Only CO2, 2013

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http://www.jaxa.jp/press/2009/02/20090209_ibuki_e.html#at1

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http://www.jaxa.jp/press/2009/02/20090209_ibuki_e.html#at1

GOSAT (CO2, CH4)

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http://www.jaxa.jp/press/2009/02/20090209_ibuki_e.html#at1

SCIAMACHY (CH4)

GOSAT (CO2, CH4)

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http://www.jaxa.jp/press/2009/02/20090209_ibuki_e.html#at1

SCIAMACHY (CH4)

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http://www.jaxa.jp/press/2009/02/20090209_ibuki_e.html#at1

TROPOMI

CH4 and CO(and H2O)

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One of the most critical issues is scattering byaerosols and cirrus (cloud-free observations)

Sciamachy CO2 TOMS AI

July:

October:

SaharaSCIAMACHY CO2

Houweling et al., ACP (2005) 370 ppm 390 ppm

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SCIAMACHY, GOSAT (1.6 mm)

GOSAT (0.75,1.6 ,2,2.1 mm) , TROPOMI (0.75 & 2.3 mm)

, heritage Sciamachy

Neither method is perfect, methods can be tested using GOSAT

Frankenberg et al., Science 2005

RemoteC algorithms

2003-2008 SCIAMACHY average

Frankenberg, Science 2005

Time-series over the Sahara

Increase in methane observed as of 2007

Frankenberg, JGR 2011

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GOSAT : 1st dedicated GHG mission (2009 - …)

Multi-band high spectral resolution FTIRCircular FOV, 10 km

Cloud Aerosol ImagerHigh spatial resolution 500 meter

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Validation columns CH4 and CO2 GOSAT :Total Carbon Column Observing Network (TCCON)

Ground-based network of FTIR spectrometers set up for thevalidation of satellite based CO2 (and CH4, N2O, HF ,CO, H2O and HDO) column measurements.

We used 12 stations for validation of our GOSAT CH4 and CO2 columns

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CO2

Processed ~ 1,5 years

station-to-station bias variability : ~0.23% (stdv)

Scatter ~ 1%

Butz, GRL 2011

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station-to-station bias variability : ~0.23% (stdv)

Scatter ~ 1%

Proxy and Full-Physics show very similar TCCON comparison

CH4

Butz, GRL 2011

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Number of important corrections applied :

- Ad-hoc additive offset correction to correct for non-linearity- O2 scaling to correct for probably spectroscopy issues- Apply cirrus filter

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Global data set ~ 1.5 years

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GOSAT XCH4 proxy vs full physics: from the comparison with TCCON, the 2 data products have similar quality. Comparison of the global maps over one year :

Sahara shows the greater difference: overestimation from full physics, due to high albedo + aerosol load? Remark: those are seasonal biases

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CH4 Proxy versus full physics method :

- TM5-NOAA always lower- Difference between proxy and full physics GOSAT in spring-summer. Proxy lower.- Spring-summer dust storm periods overestimation by full physics due to high aerosol load and high albedo

Sahara

Schepers, 2011

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India

CH4/CO2

CO2 full physics

CO2 Carbon Tracker

Carbon Tracker not perfect, effect visible in proxy CH4

• The ESA Sentinel-5 Precursor (S-5P) is a pre-operational mission focussing on global observations of the atmospheric composition for air quality and climate.

• The TROPOspheric Monitoring Instrument (TROPOMI) is the payload of the S-5P mission and is jointly developed by The Netherlands and ESA.

• The planned launch date for S-5P is 2014 with a 7 year design lifetime.

sentinel-5 precursorGMES ATMOSPHERE MISSION IN POLAR ORBIT

‣ TROPOMI: UV-VIS-NIR-SWIR push-broom grating spectrometer.

‣ Spectral range: 270-500 nm, 675-775 nm, 2305-2385 nm

‣ Spectral Resolution: 0.25-1.1 nm

‣ Observation Mode: Nadir, global daily coverage, ground pixel 7x7km2 at nadir

‣ Orbit: Sun synchronous, 824 km, 13:30 hr dayside equator crossing time.

SATELLITE PAYLOAD

‣O3: total and tropospheric column, profile

‣NO2: tropospheric and total column

‣CO: total column

‣SO2: total column

‣CH4: total column

‣Aerosol: absorbing index, type, optical depth

‣CH2O: tropopsheric column

‣H2O: total column

‣BrO: total column

CONTRIBUTION TO GMES SERVICES

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CH4 TROPOMI simulations cirrus/aerosol error :

TROPOMI is able to correct – to large extent- for lightpath modificationdue to cirrus/aerosols, in fact similarly to GOSAT. Other wavelength band, and lower spectral resolution.

Butz, Rem.Sens.Environ. 2011

Project lead : Michael Buchwitz,Institute of Environmental Physics (IUP), University of Bremen, Bremen, Germany

Essential Climate Variable (ECV)Greenhouse Gases (GHG), CO2 & CH4

ESA Climate Change Initiative :Provide consistent long term data on ECVs from space

GHG-CCI Project Overview

• Goal: To deliver global atmospheric CO2 and CH4 information needed for a better understanding of regional GHG surface fluxes (sources & sinks)

• Core products: Column-averaged near-surface-sensitive CO2 and CH4, i.e., XCO2 and XCH4, from SCIAMACHY/ENVISAT & TANSO-FTS/GOSAT; generated with ECV Core Algorithms (ECAs); several ECAs per product in competition; the best algorithm for a given product will be selected after 2 year Round Robin phase with several algorithm-improvement – processing – analysis cycles

• Additional constraints products: CO2 and CH4 profiles and partial columns from AIRS, IASI, ACE-FTS, MIPAS, SCIAMACHY solar occultation; generated with Additional Constraints Algorithms (ACAs)

• ECV generation: In year 3 using selected best algorithm(s) (+ intermediate products if available)

• Activities: User requirements definition, algorithm improvements, data processing and analysis, calibration improvements, validation, ...

• Linked to and complementary with European GMES Global Atmospheric Core Service (MACC & follow-ons)

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summary :

• SCIAMACHY already provides since 2003 important 1st global view on CH4 columns from space. Used in global emission inversions.

• GOSAT 1st dedicated greenhouse gas mission now providing its 1st results for CH4 and CO2. Validation with TCCON stations shows very promising results : Station-to-station bias variability ~a few tens of a percent, scatter <1% Global data processing on-going, ready for source/sink inversions.

GOSAT data is ideally suited to test different retrieval approaches

• TROPOMI Precursor Sentinel 5 will continue SCIAMACHY and GOSAT CH4 series as of ~2015, followed by Sentinel 5 from 2020 onwards

Space based observations of CH4 and CO2 look very promising !!!

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Challenge: accuracy

Houweling et al., ACP, 2010

“precisions of 1-2 ppm [out of roughly 380 ppm] are needed on regional scales to improve our knowledge of carbon cycle phenomena” (Miller et al., JGR, 2007)

“failure to limit the regional biases to within a few tenths of a part per million would have a detrimental impact on the flux estimation” (Chevallier et al., JGR, 2006)

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Retrieval method: concept

[ CO2 vertical profile and/or CH4 vertical profile, scattering parameters, surface parameters, instrument parameters]

(vector) RTM

+ parameterization of particle amount, size, type, height

Minimize Phillips-Tikhonov cost function:

GOSAT / OCO-2 / TROPOMI observations in the SWIR

Butz et al., Appl. Opt., 2009; JGR, 2010; RSE, submitted.

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Retrieval method: forward model

Butz et al., Appl. Opt., 2009; JGR, 2010; RSE, submitted.

Parameterized height distribution: Gaussian function of center height zs

Parameterized particle size distribution: Power-law with size parameter as

Particle amount: Ns [particles/cm2]

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GOSAT: retrieval setup - details

Spectroscopy: Hartmann + Tran, line-mixing (O2, CO2) and collision induced absorption (O2), HITRAN 2008

Meteorology (p, T, H2O): ECMWF ERA interim analysis (1.5º x1.5º, 6 hourly)

Surface topography: GTOPO30 database

Initial guess CO2, CH4:CarbonTracker, TM4

Cloud screening:TANSO-CAI L2 product

Measurements:Total radiance (Stokes’ I) from TANSO-FTS L1B product

Instrument: Polarization model by A. Kuze, D. O’Brien.

Solar model:Geoff Toon's linelist

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Performance evaluation: “full-physics” method - GOSAT

Full physics vs proxy-CO2 vs non-scattering

red blue black

7 years of SCIAMACHY data (2003-2009)

Frankenberg et al, JGR 2011

Alternative view:- increase 2007 in CH4 evident- clear variations visible in Tropics (can not be 'seen' by Surface network)- Negative tropical anomaly in 2006

Inverse modeling using satelliteand surface network neededto further investigate

Need also to further investigateeffect radiation damage