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Evaluation of column-averaged methane in models and TCCON with a focus on the stratosphere

Journal Article


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Abstract


  • The distribution of methane (CH4/ in the stratosphere

    can be a major driver of spatial variability in the dryair

    column-averaged CH4 mixing ratio (XCH4), which is being

    measured increasingly for the assessment of CH4 surface

    emissions. Chemistry-transport models (CTMs) therefore

    need to simulate the tropospheric and stratospheric fractional

    columns of XCH4 accurately for estimating surface

    emissions from XCH4. Simulations from three CTMs are

    tested against XCH4 observations from the Total Carbon

    Column Network (TCCON). We analyze how the model–

    TCCON agreement in XCH4 depends on the model representation

    of stratospheric CH4 distributions. Model equivalents

    of TCCON XCH4 are computed with stratospheric CH4

    fields from both the model simulations and from satellitebased

    CH4 distributions from MIPAS (Michelson Interferometer

    for Passive Atmospheric Sounding) and MIPAS CH4

    fields adjusted to ACE-FTS (Atmospheric Chemistry Experiment

    Fourier Transform Spectrometer) observations. Using

    MIPAS-based stratospheric CH4 fields in place of model

    simulations improves the model–TCCON XCH4 agreement

    for all models. For the Atmospheric Chemistry Transport

    Model (ACTM) the average XCH4 bias is significantly reduced

    from 38.1 to 13.7 ppb, whereas small improvements

    are found for the models TM5 (Transport Model, version 5;

    from 8.7 to 4.3 ppb) and LMDz (Laboratoire de Météorologie

    Dynamique model with zooming capability; from 6.8 to

    4.3 ppb). Replacing model simulations with MIPAS stratospheric

    CH4 fields adjusted to ACE-FTS reduces the average

    XCH4 bias for ACTM (3.3 ppb), but increases the average

    XCH4 bias for TM5 (10.8 ppb) and LMDz (20.0 ppb). These

    findings imply that model errors in simulating stratospheric

    CH4 contribute to model biases. Current satellite instruments

    cannot definitively measure stratospheric CH4 to sufficient

    accuracy to eliminate these biases. Applying transport diag-

    nostics to the models indicates that model-to-model differences

    in the simulation of stratospheric transport, notably the

    age of stratospheric air, can largely explain the inter-model

    spread in stratospheric CH4 and, hence, its contribution to

    XCH4. Therefore, it would be worthwhile to analyze how individual

    model components (e.g., physical parameterization,

    meteorological data sets, model horizontal/vertical resolution)

    impact the simulation of stratospheric CH4 and XCH4.

UOW Authors


  •   Ostler, A (external author)
  •   Sussmann, Ralf (external author)
  •   Patra, Prabir K. (external author)
  •   Houweling, Sander (external author)
  •   De Bruine, Marko (external author)
  •   Stiller, G P. (external author)
  •   Haenel, Florian (external author)
  •   Plieninger, Johannes (external author)
  •   Bousquet, Philippe J. (external author)
  •   Yin, Yi (external author)
  •   Saunois, Marielle (external author)
  •   Walker, K A. (external author)
  •   Deutscher, Nicholas
  •   Griffith, David
  •   Blumenstock, Thomas (external author)
  •   Hase, Frank (external author)
  •   Warneke, Thorsten (external author)
  •   Wang, Zhiting (external author)
  •   Kivi, Rigel (external author)
  •   Robinson, John (external author)

Publication Date


  • 2016

Citation


  • Ostler, A., Sussmann, R., Patra, P. K., Houweling, S., De Bruine, M., Stiller, G. P., Haenel, F. J., Plieninger, J., Bousquet, P., Yin, Y., Saunois, M., Walker, K. A., Deutscher, N. M., Griffith, D. W. T., Blumenstock, T., Hase, F., Warneke, T., Wang, Z., Kivi, R. & Robinson, J. (2016). Evaluation of column-averaged methane in models and TCCON with a focus on the stratosphere. Atmospheric Measurement Techniques, 9 (9), 4843-4859.

Scopus Eid


  • 2-s2.0-84990057252

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=5198&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/4174

Has Global Citation Frequency


Number Of Pages


  • 16

Start Page


  • 4843

End Page


  • 4859

Volume


  • 9

Issue


  • 9

Place Of Publication


  • Germany

Abstract


  • The distribution of methane (CH4/ in the stratosphere

    can be a major driver of spatial variability in the dryair

    column-averaged CH4 mixing ratio (XCH4), which is being

    measured increasingly for the assessment of CH4 surface

    emissions. Chemistry-transport models (CTMs) therefore

    need to simulate the tropospheric and stratospheric fractional

    columns of XCH4 accurately for estimating surface

    emissions from XCH4. Simulations from three CTMs are

    tested against XCH4 observations from the Total Carbon

    Column Network (TCCON). We analyze how the model–

    TCCON agreement in XCH4 depends on the model representation

    of stratospheric CH4 distributions. Model equivalents

    of TCCON XCH4 are computed with stratospheric CH4

    fields from both the model simulations and from satellitebased

    CH4 distributions from MIPAS (Michelson Interferometer

    for Passive Atmospheric Sounding) and MIPAS CH4

    fields adjusted to ACE-FTS (Atmospheric Chemistry Experiment

    Fourier Transform Spectrometer) observations. Using

    MIPAS-based stratospheric CH4 fields in place of model

    simulations improves the model–TCCON XCH4 agreement

    for all models. For the Atmospheric Chemistry Transport

    Model (ACTM) the average XCH4 bias is significantly reduced

    from 38.1 to 13.7 ppb, whereas small improvements

    are found for the models TM5 (Transport Model, version 5;

    from 8.7 to 4.3 ppb) and LMDz (Laboratoire de Météorologie

    Dynamique model with zooming capability; from 6.8 to

    4.3 ppb). Replacing model simulations with MIPAS stratospheric

    CH4 fields adjusted to ACE-FTS reduces the average

    XCH4 bias for ACTM (3.3 ppb), but increases the average

    XCH4 bias for TM5 (10.8 ppb) and LMDz (20.0 ppb). These

    findings imply that model errors in simulating stratospheric

    CH4 contribute to model biases. Current satellite instruments

    cannot definitively measure stratospheric CH4 to sufficient

    accuracy to eliminate these biases. Applying transport diag-

    nostics to the models indicates that model-to-model differences

    in the simulation of stratospheric transport, notably the

    age of stratospheric air, can largely explain the inter-model

    spread in stratospheric CH4 and, hence, its contribution to

    XCH4. Therefore, it would be worthwhile to analyze how individual

    model components (e.g., physical parameterization,

    meteorological data sets, model horizontal/vertical resolution)

    impact the simulation of stratospheric CH4 and XCH4.

UOW Authors


  •   Ostler, A (external author)
  •   Sussmann, Ralf (external author)
  •   Patra, Prabir K. (external author)
  •   Houweling, Sander (external author)
  •   De Bruine, Marko (external author)
  •   Stiller, G P. (external author)
  •   Haenel, Florian (external author)
  •   Plieninger, Johannes (external author)
  •   Bousquet, Philippe J. (external author)
  •   Yin, Yi (external author)
  •   Saunois, Marielle (external author)
  •   Walker, K A. (external author)
  •   Deutscher, Nicholas
  •   Griffith, David
  •   Blumenstock, Thomas (external author)
  •   Hase, Frank (external author)
  •   Warneke, Thorsten (external author)
  •   Wang, Zhiting (external author)
  •   Kivi, Rigel (external author)
  •   Robinson, John (external author)

Publication Date


  • 2016

Citation


  • Ostler, A., Sussmann, R., Patra, P. K., Houweling, S., De Bruine, M., Stiller, G. P., Haenel, F. J., Plieninger, J., Bousquet, P., Yin, Y., Saunois, M., Walker, K. A., Deutscher, N. M., Griffith, D. W. T., Blumenstock, T., Hase, F., Warneke, T., Wang, Z., Kivi, R. & Robinson, J. (2016). Evaluation of column-averaged methane in models and TCCON with a focus on the stratosphere. Atmospheric Measurement Techniques, 9 (9), 4843-4859.

Scopus Eid


  • 2-s2.0-84990057252

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=5198&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/4174

Has Global Citation Frequency


Number Of Pages


  • 16

Start Page


  • 4843

End Page


  • 4859

Volume


  • 9

Issue


  • 9

Place Of Publication


  • Germany