HYMN: Hydrogen, Methane and Nitrous oxide: Trend variability, budgets and interactions with the biosphere GOCE-CT TM4 model evaluations and TM5 decadal runs Michiel van Weele HYMN meeting, Bremen 6-7 April 2009

Evaluation of emissions and concentration distributions using in-situ and satellite observations HYMN modelling activities I. Focus on the year 2004 ( ) II. Decadal runs ( ) Anthropogenic emissions bottom-up inventories CO, NOx etc A posteriori methane emission distributions from inverse modelling Net natural fluxes methane Global dynamical vegetation modelling (LPJ) Chemical-transport model simulations BQT: Bousquet a posteriori emissions and natural fluxes LPJ: Natural fluxes from LPJ replacing Bousquet natural fluxes Evaluations: Latitudinal distribution Seasonal cycle Station time series Comparisons against SCIAMACHY Comparisons against FTIR tropospheric and total column observations

Use of CTMs to better constrain the global methane budget? Chemistry-transport modelling relates inventories and calculated emission distributions to surface concentration observations E.g. The inter-hemispheric CH 4 gradient allows about ~1/3 of CH4 emissions between 30-90N and ~2/3 in the Tropics(+ Southern Hemisphere) CTM modelling is needed to interpret column VMR satellite observations and to relate the satellite data to surface emissions (regional distribution, seasonality)

Effect of a latitudinal shift in CH4 emissions on the Inter Hemispheric Gradient Shifting 5% (or 26 Tg CH4) from tropics to northern hemisphere: Increases the Inter-Hemispheric Gradient (IHG) from 120 to 138 ppb (after 1 year of simulation, new SH steady state not yet reached) Observed IHG (2004): 129 ppb (using NOAA/GMD stations Alert and South Pole) Effects on CH4 lifetime are negligible solid line Tropics58% NH30% Dotted line Tropics53% NH35% Plus signs NOAA/GMD monthly means for Alert and South Pole

Column VMR and Surface VMR Satellite CH4 observations relate to column-averaged concentration distributions Anthropogenic emissions + natural fluxes relate to surface concentration distributions All figures show August 2004

Methane lifetime TM4; spatial resolution: (lon x lat) 3 x2 degrees; 34 layers in vertical; Years CH4 budget CH4 Emissions (Bousquet a-posteriori) 534 Tg/a CH4 burden4832 Tg Loss via tropospheric OH 498 Tg/a Loss in stratosphere 24 Tg/a CH4 soil sink 25 Tg/a CH4 trend -13 Tg/a CH4 lifetime 4832 / yrs OH budget Relative contributions OH loss: OH + CO40%OH + H2 5% OH + CH416%OH + HO2 5% OH + ROOH15%OH + Isoprene 4% OH + O3 5%OH + H2O2 4% OH + HCHO 5%OH + Other 1% Relative contributions OH production: O3 + hv~50%OH recycling (eg NOx)~40%peroxides~10%  Feedbacks on CH4 lifetime dominated by changes in CO (Half of CO is produced from CH4 and NMHC oxidation)  CH4 lifetime changes related to CO and NOx (modulated by VOCs)

Bottom-up inventories Annual mean for 2004 (in Gg/cell/ month) Anthropogenic CH4 emissions Including rice paddies Excluding biomass burning

Bousquet a posteriori year 2004 Monthly mean surface methane concentrations near Sumatra

Natural methane flux spatial distribution (LPJ) Sum of wetlands (inundated areas), wet soils, northern peatlands and soil consumption (flux < 0 ) August 2004

Natural methane flux spatial distribution (LPJ) Feb – Apr – Aug – Nov 2004

Seasonal variation in natural methane fluxes (LPJ) BlackTotal net flux RedWet SoilsPurpleNorthern Peatlands BlueWetlandsGreenSoil Sink Tropical 30 – 90 N

LPJ interannual variability/trend in natural methane fluxes

Evaluation against surface observations

TM4 evaluation at 3 tropical sites: Assekrem(23N), Sumatra(Eq), Mt Kenya (Eq) Red: Observations Blue: BQT Green: LPJ Large signs: monthly means

Evaluation against SCIAMACHY observations

TM4 model validation per region with SCIAMACHY

Model validation per region with SCIAMACHY AmericasAfricaEurasia Indo Aus AtlanticPacific-IndianPolar Regional mean column mixing ratio’s (in ppbv) for year 2004 SCIA = SCIAMACHY observations TM4BQT = a posteriori emission distribution Philippe TM4LPJ = idem, but with LPJ CH4 fluxes replacing wetlands, rice, and soil sink

Absolute differences in regional mean column mixing ratios (in ppbv) SCIA = SCIAMACHY observations TM4BQT = a posteriori emission distribution TM4LPJ = idem, but with LPJ CH4 emissions replacing wetlands+rice AmericasAfricaEurasia Indo Aus AtlanticPacific-IndianPolar

Comparison for 13 land regions between TM4 / SCIA differences and Lisa’s surface station optimizations per region Aug 2004

Comparison for 13 land regions between TM4 / SCIA differences and Lisa’s surface station optimizations per region Year 2004

TM5 ‘B07’ post-prior CH 4 column mixing ratio increments (ppmv) TM5 ‘BQT’ post-prior CH 4 column mixing ratio increments (ppmv) Aug 2004

TM5 ‘B07’ post-prior CH 4 column mixing ratio increments (ppmv) TM5 ‘BQT’ post-prior CH 4 column mixing ratio increments (ppmv) Jun 2004

Long runs (AC en C slides)

TM5 Preliminary CH4 budget analysis (year 2000) Prescribed (observed) zonal-mean mixing ratios at the surface Above 50 (tropical)/90 hPa (extra-tropical) nudging to HALOE-CLAES climatology Grooß and Russell III, Technical note: A stratospheric climatology for O3, H2O, CH4, NOx,HCl and HF derived from HALOE measurements, Atmos. Chem. Phys., 5, 2797–2807, 2005 CH4 + OH (troposphere)406 Tg/a <= 15% lower than TM4 (under investigation....) CH4 + OH (lower stratosphere) 20 Tg/a Stratospheric nudging 34 Tg/amore strat. loss (54 Tg) Burden change -12 Tg/a Net CH4 emission – soil sink448 Tg/a

Next months Further evaluations sensitivity runs against observations (SCIA, FTIR, surface) TM4 run with a-posterior LPJ distribution Lisa? Continuation of TM5 decadal runs and ~ 3 days per simulation year => first set ready in May Multi-annual CH 4 budget / lifetime analysis based on TM5 “separate concentration changes caused by lifetime change from concentration changes caused by emission changes” Analysis of meteorology affecting interannual OH (total ozone, temperature, humidity, solar radiation, clouds, albedo)