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TransCom N2O model inter-comparison – Part 2: Atmospheric inversion estimates of N2O emissions

Thompson, R. L.; Ishijima, K.; Saikawa, E.; Corazza, M.; Karstens, Ute LU ; Patra, P. K.; Bergamaschi, P.; Chevallier, F.; Dlugokencky, E. and Prinn, R. G., et al. (2014) In Atmospheric Chemistry and Physics 14(12). p.6177-6194
Abstract
This study examines N2O emission estimates from five different atmospheric inversion frameworks based on chemistry transport models (CTMs). The five frameworks differ in the choice of CTM, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation data set. The posterior modelled atmospheric N2O mole fractions are compared to observations to assess the performance of the inversions and to help diagnose problems in the modelled transport. Additionally, the mean emissions for 2006 to 2008 are compared in terms of the spatial distribution and seasonality. Overall, there is a good agreement among the inversions for the mean global total emission, which ranges from 16.1 to 18.7 TgN yr(-1) and... (More)
This study examines N2O emission estimates from five different atmospheric inversion frameworks based on chemistry transport models (CTMs). The five frameworks differ in the choice of CTM, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation data set. The posterior modelled atmospheric N2O mole fractions are compared to observations to assess the performance of the inversions and to help diagnose problems in the modelled transport. Additionally, the mean emissions for 2006 to 2008 are compared in terms of the spatial distribution and seasonality. Overall, there is a good agreement among the inversions for the mean global total emission, which ranges from 16.1 to 18.7 TgN yr(-1) and is consistent with previous estimates. Ocean emissions represent between 31 and 38% of the global total compared to widely varying previous estimates of 24 to 38%. Emissions from the northern mid- to high latitudes are likely to be more important, with a consistent shift in emissions from the tropics and subtropics to the mid- to high latitudes in the Northern Hemisphere; the emission ratio for 0-30A degrees N to 30-90A degrees N ranges from 1.5 to 1.9 compared with 2.9 to 3.0 in previous estimates. The largest discrepancies across inversions are seen for the regions of South and East Asia and for tropical and South America owing to the poor observational constraint for these areas and to considerable differences in the modelled transport, especially inter-hemispheric exchange rates and tropical convective mixing. Estimates of the seasonal cycle in N2O emissions are also sensitive to errors in modelled stratosphere-to-troposphere transport in the tropics and southern extratropics. Overall, the results show a convergence in the global and regional emissions compared to previous independent studies. (Less)
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type
Contribution to journal
publication status
published
subject
in
Atmospheric Chemistry and Physics
volume
14
issue
12
pages
6177 - 6194
publisher
Copernicus Gesellschaft Mbh
external identifiers
  • wos:000338438300020
  • scopus:84902978776
ISSN
1680-7324
DOI
10.5194/acp-14-6177-2014
language
English
LU publication?
no
id
780797cc-5648-40d2-bde5-6fcfa721405b (old id 4623683)
date added to LUP
2014-09-26 08:11:17
date last changed
2017-11-16 14:23:22
@article{780797cc-5648-40d2-bde5-6fcfa721405b,
  abstract     = {This study examines N2O emission estimates from five different atmospheric inversion frameworks based on chemistry transport models (CTMs). The five frameworks differ in the choice of CTM, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation data set. The posterior modelled atmospheric N2O mole fractions are compared to observations to assess the performance of the inversions and to help diagnose problems in the modelled transport. Additionally, the mean emissions for 2006 to 2008 are compared in terms of the spatial distribution and seasonality. Overall, there is a good agreement among the inversions for the mean global total emission, which ranges from 16.1 to 18.7 TgN yr(-1) and is consistent with previous estimates. Ocean emissions represent between 31 and 38% of the global total compared to widely varying previous estimates of 24 to 38%. Emissions from the northern mid- to high latitudes are likely to be more important, with a consistent shift in emissions from the tropics and subtropics to the mid- to high latitudes in the Northern Hemisphere; the emission ratio for 0-30A degrees N to 30-90A degrees N ranges from 1.5 to 1.9 compared with 2.9 to 3.0 in previous estimates. The largest discrepancies across inversions are seen for the regions of South and East Asia and for tropical and South America owing to the poor observational constraint for these areas and to considerable differences in the modelled transport, especially inter-hemispheric exchange rates and tropical convective mixing. Estimates of the seasonal cycle in N2O emissions are also sensitive to errors in modelled stratosphere-to-troposphere transport in the tropics and southern extratropics. Overall, the results show a convergence in the global and regional emissions compared to previous independent studies.},
  author       = {Thompson, R. L. and Ishijima, K. and Saikawa, E. and Corazza, M. and Karstens, Ute and Patra, P. K. and Bergamaschi, P. and Chevallier, F. and Dlugokencky, E. and Prinn, R. G. and Weiss, R. F. and O'Doherty, S. and Fraser, P. J. and Steele, L. P. and Krummel, P. B. and Vermeulen, Alex and Tohjima, Y. and Jordan, A. and Haszpra, L. and Steinbacher, M. and Van der Laan, S. and Aalto, T. and Meinhardt, F. and Popa, M. E. and Moncrieff, J. and Bousquet, P.},
  issn         = {1680-7324},
  language     = {eng},
  month        = {06},
  number       = {12},
  pages        = {6177--6194},
  publisher    = {Copernicus Gesellschaft Mbh},
  series       = {Atmospheric Chemistry and Physics},
  title        = {TransCom N2O model inter-comparison – Part 2: Atmospheric inversion estimates of N2O emissions},
  url          = {http://dx.doi.org/10.5194/acp-14-6177-2014},
  volume       = {14},
  year         = {2014},
}