Satellite data constraints on the seasonal methane budget. A.Anthony Bloom 1*, Kevin Bowman 1, Meemong Lee 1, John Worden 1, Alex Turner 2, Daniel Jacobs 2, Ronny Schroeder 3, Kyle McDonald 3. 1 Jet Propulsion Laboratory/California Institute of Technology 2 Harvard University, Department of Environmental Engineering, MA 3 City College of New York, NY IGC7 – May 5 th 2015 A. Anthony Bloom, JPL - IGC7, May 5 th 2015

Wetland CH 4 emissions: 20-40% of global CH 4 budget A. Anthony Bloom, JPL - IGC7, May 5 th 2015 Magnitude, timing and location of wetland CH 4 fluxes uncertain Process controls on wetlands important to understand the CH 4 budget Process controls fundamental to understanding long-term climate feedbacks Tg CH 4 /yr WETCHIMP models

Wetland CH 4 emission controls: F CH4 = A  C  f(T)  e A = Wetland Extent T= Temperature C = Methanogen-available carbon e = Emission factor

GEOS-Chem: updated wetland CH 4 emissions inventory. Wetland CH 4 emissions = W AREA × C × f(T) x e Equation adapted from Pickett-Heaps et al., 2011 A. Anthony Bloom, JPL - IGC7, May 5 th 2015 MsTMIP Terrestrial Biosphere models Satellite-based inundated area (MEaSUREs & GIEMS: based on satellite active/passive microwave sensor data) Scaled to global total: 210 +/-50 Tg CH 4 yr -1 (consistent with mean and std of IPCC 5 th AR)

1.Carbon and inundated area drive seasonal and inter-annual variability 2.Differences largely in the timing and magnitude of emissions 3.Larger fluxes in North America and Boreal Eurasia wetland areas & later fluxes (Aug- September) in temperate and boreal latitudes. Updated wetland CH 4 year = 2010, Bloom et al., 2015, in prep. A. Anthony Bloom, JPL - IGC7, May 5 th 2015 Standard wetland CH 4 MeanMonthly (%)

A. Anthony Bloom, JPL - IGC7, May 5 th 2015 Barrow (71N 157W ) Key Biscayne (26N 80W) Correlation [GEOS-Chem standard & surface CH 4 ] Correlation [GEOS-Chem updated & surface CH4] Surface CH4 comparisons Updated CH4 inventory leads to overall improved CH4 variability Largest improvements in N. America within proximity of major wetland emissions CH 4 anomaly [ppb] 1:1 STANDARD UPDATED SURFACE OBS STANDARD UPDATED SURFACE OBS CH 4 anomaly [ppb]

A. Anthony Bloom, JPL - IGC7, May 5 th 2015 GOSAT GEOS-Chem Standard wetland fluxes GEOS-Chem MEaSUREs MstMIP wetlands Boreal CH4 error could be explained by a systematic bias in the magnitude and timing of wetlands

A. Anthony Bloom, JPL - IGC7, May 5 th 2015 GOSAT GEOS-Chem Standard wetland CH4 inventory GEOS-Chem Updated wetland CH4 inventory GEOS-Chem Uniform wetland fluxes (no spatiotemporal variability) Temperate/Boreal CH4 error unlikely to be explained by differences in wetlands.

GOSAT GEOS-Chem Updated wetland CH4 GEOS-Chem No CH 4 OH loss GEOS-Chem Constant CH 4 OH loss A. Anthony Bloom, JPL - IGC7, May 5 th 2015 Constant/No OH loss lead to lower mismatch between model CH 4 seasonality

Conclusions Improved seasonal agreement between surface observations and updated GEOS-Chem wetland CH 4 inventory. Temperate/boreal latitude GOSAT CH 4 seasonal cycle not explained by wetland emissions. GOSAT model mismatch could potentially be explained by a bias in Northern latitude OH A. Anthony Bloom, JPL - IGC7, May 5 th 2015

Master copy Feb 23 WETLANDS CH 4 (approx. 200 TgCH 4 ) Anaerobic respiration Foliage Wood Soil Carbon Litter atmosphere biosphere Roots Gross Primary Production (approx PgC) Ecosystem Respiration (approx PgC) Live biomass Dead organic matter Heterotrophic Respiration Auto. Resp. Wetland and fire emissions are derived from carbon pools with different residence times A. Anthony Bloom, Yuk Lunch Seminar Series, Caltech, Mar 3 rd 2015

GEOS-Chem: Updated wetland CH 4 emissions inventory. Wetland CH 4 emissions model = W AREA × C resp × f(Temp) x S Equation adapted from Pickett-Heaps et al., 2011 A. Anthony Bloom, Yuk Lunch Seminar Series, Caltech, Mar 3 rd 2015