AGAGE and CSIRO Measurements of Recent Global Methane Growth Matt - - PowerPoint PPT Presentation

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AGAGE and CSIRO Measurements of Recent Global Methane Growth Matt - - PowerPoint PPT Presentation

Sep 25, 2023 366 likes •532 views

AGAGE and CSIRO Measurements of Recent Global Methane Growth Matt Rigby, Ron Prinn, Paul Fraser, Peter Simmonds, Ray Langenfelds, Jin Huang, Derek Cunnold, Paul Steele, Paul Krummel, Ray Weiss, Simon ODoherty, Peter Salameh, Ray Wang, Chris

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SLIDE 1

AGAGE and CSIRO Measurements

  • f Recent Global Methane Growth

Matt Rigby, Ron Prinn, Paul Fraser, Peter Simmonds, Ray Langenfelds, Jin Huang, Derek Cunnold, Paul Steele, Paul Krummel, Ray Weiss, Simon O’Doherty, Peter Salameh, Ray Wang, Chris Harth, Jens Mühle, Laurie Porter May 2009

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SLIDE 2

AGAGE network

  • Advanced Global Atmospheric Gases Experiment
  • High frequency measurements of ozone depleting species

and non-CO2 GHGs

Matt Rigby, June 2008 Page 2 agage.eas.gatech.edu

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SLIDE 3

CSIRO flask network

  • ~4 flasks per month analysed at CSIRO

Matt Rigby, May 2009 Page 3 cdiac.ornl.gov

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SLIDE 4

Renewed CH4 growth: AGAGE

Matt Rigby, June 2008 Page 4

Rigby et al. 2008, Renewed Growth of Atmospheric Methane, GRL 35, L22805

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SLIDE 5

Renewed CH4 growth: CSIRO

Matt Rigby, June 2008 Page 5

Rigby et al. 2008, Renewed Growth of Atmospheric Methane, GRL 35, L22805

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SLIDE 6

Box model inversion

Matt Rigby, June 2008 Page 6

90N 30N 0N 30S 90S 1000hPa 500hPa 200hPa

OH

OH

OH

OH OH

OH

OH

OH OH OH OH

OH

  • Seasonally varying transport parameters from climatology

+ CFC inversion

  • OH from methyl chloroform inversion
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SLIDE 7

Constant OH: Hemispheric emissions

  • ~ 40 Tg/yr increase from 2006 – 2007 (5-6%)
  • ~ 22 Tg /yr NH (5%), ~18 Tg/yr SH (10%)

Matt Rigby, October 2008 Page 7

  • Inter-annually repeating OH

Annual running means

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SLIDE 8

What changed in 2007?

  • Anomalous high temperatures over boreal wetlands

Matt Rigby, June 2008 Page 8

  • Wetland emission ~ temperature (and other factors)? /

Melting permafrost??

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SLIDE 9

What changed in 2007?

  • Biomass burning? CO increase?

Matt Rigby, June 2008 Page 9

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SLIDE 10

Influence of inter-annually varying meteorology

Matt Rigby, May 2009 Page 10

  • MOZART 4.5 + NCEP reanalysis + GFED v2
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SLIDE 11

Sensitivity to Northern emissions

Matt Rigby, May 2009 Page 11

  • 10% emissions increase 30N – 90N (1 year pulse)

2006 2007

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SLIDE 12

Sensitivity to tropical emissions

Matt Rigby, May 2009 Page 12

  • 10% emissions increase 30N – 30S (1 year pulse)
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SLIDE 13

OH decrease?

  • Methyl chloroform inversion: 4±14% OH drop in 2007
  • CH4 increase: 20Tg/yr global, 13Tg/yr NH, 7Tg/yr SH

Matt Rigby, October 2008 Page 13

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SLIDE 14

OH decrease?

Matt Rigby, May 2009 Page 14

  • Potential causes: CO , (CH4 ), stratospheric O3 ,

H2O , tropospheric O3 …

Specific humidity (% change) Total column ozone (% change)

NH SH NH SH

NCEP reanalysis: weighted by OH concentration NIMBUS-7/METEOR-3/EP/OMI data from climexp.knmi.nl

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SLIDE 15

Conclusions

  • 2007 – present: renewed global methane growth following

almost a decade of relatively stable levels

  • If no OH change, then substantial emissions increase

required in both hemispheres

  • Changes in meteorology or biomass burning emissions do

not appear to be responsible

  • A small (and NOT statistically significant) drop in OH is

inferred, but the cause of such a drop is unclear

Matt Rigby, June 2008 Page 15