Inverse modelling of methane sources and sinks using satellite observations

Methane inversion from satellite, TRANSCOM workshop, Jena, 12-15 May 2003

Inverse modelling of methane sources and sinks using satellite

observations Jan Fokke Meirink, Henk

Eskes, Michiel van Weele, Albert Goede

Royal Netherlands Meteorological Institute (KNMI)

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Overview

EVERGREEN SCIAMACHY inverse modelling strategy first experiments

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

EVERGREENEnVisat for Environmental Regulation of

GREENhouse gases

EC 5th framework programme Feb. 2003 – Feb. 2006 Objective: use ENVISAT (SCIAMACHY and MIPAS)

measurements for inverse modelling of GHG emissions

Partners: KNMI (NL, coordinator), Univ. Bremen (DE), Univ. Leicester (GB), Univ. Heidelberg (DE), NILU (NO), SRON (NL), MPI-BGC (DE), BIRA-IASB (BE), UPMC-SA (FR), RWE-Rheinbraun (DE), Univ. Liège (BE), EC-JRC-IES (IT)

website: http://www.knmi.nl/evergreen

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

EVERGREEN: tasks

Retrieval and validation: CH4, CO, (CO2), O2 columns; clouds

Radiation budget modelling: use of measured trace gas distributions in radiative forcing calculations

(Inverse) modelling: CH4, CO, CO2 emission inventory (forward) model intercomparison (222Rn, SF6,

...) inverse modelling

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

SCIAMACHY on ENVISAT

CH4

CO

CO2

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

SCIAMACHY measurements

No useful retrievals yet: calibration problems (mainly dark current

correction) ice layers on the detectors, channel 7 and 8NIR retrieval quality will depend on: albedo: over water low signal-to-noise ratio solar zenith angle clouds

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

SCIAMACHY: example nadir measurements (simulated)

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Chemistry-transport model TM3 horizontal resolution: 7.5x10 / 3.75x5 / 2.5x2.5

deg vertical resolution: 19 / 31 layers up to 10 hPa slopes scheme for advection ECMWF meteorology 37 tracers (22 transported) CBM-4 scheme for NMHC chemistry nudging at model top to climatology (O3) and

UARS data (CH4) single-tracer version with OH fields from full

model

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Planned model setup in Evergreen

horizontal resolution: 2x3 deg extension of model in vertical direction:

use subset of ECMWF layers up to 0.1 hPa

nudging of CH4 to surface observations to have model reproduce measured NH-SH gradient

up-to-date emissions from WP 4100

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Inversion strategy

4D-var method adjoint model of TM3 CH4-only version has

been developed optimize surface fluxes and initial CH4

field expected: in the beginning adjustments to CH4

field, later to surface fluxes time frame: 1 week to 1 month

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

4D var (1)

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

cost function

4D var (2)

)()(

)()()(

1T

121

01T

021

0

itiiit

n

ii

bb

ii

J

yxHRyxH

ccBccc

0111 xMMMxMx ttttt

state vector x = [c,f]

background error covariance

observation error covariance

observation

observation operator

model

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

4D var (3)

gradient of the cost function

)(

)()(

1

TT

1

T10

10

itiii

iit

n

i

b

i

iJ

yxHRd

dHMMxxBx

adjoint model

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Preconditioning

S diagonal matrix with standard deviations

LLT symmetric matrix with correlations

SLAAABAdcc and with , Tb

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

First experiments First week of January 2000 Sat.obs. taken from perturbed model run Optimize emissions only Background error covariance

Standard deviation: 50% of emission Horizontal correlation function:

Gaussian with length scale of 1000 km Observation error covariance

Diagonal; standard deviation: 0.5% of column

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

A priori emissions

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Perturbed run

50% enhanced emissions

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Effect on CH4 field after one week

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Pseudo satellite observations

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Optimized CH4 emissions

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Resulting CH4 field

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Setting obs to 2%

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Adding 0.5% noise to sat.data

Methane inversion from satellite, TRANSCOM meeting, Jena,12-15 May 2003

Summary

EU project EVERGREEN for emission estimates of CH4, CO, and possibly CO2, using satellite data.

SCIAMACHY has the potential of measuring CH4 and CO columns, but first some calibration problems have to be solved.

Inverse modelling of CH4 using 4D-var has been set up at KNMI and first experiments have been done.