An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model
Nitrous oxide ( N 2 O ) is an important greenhouse gas and it can also generate nitric oxide, which depletes ozone in the stratosphere. It is a common target species of ground-based Fourier transform infrared (FTIR) near-infrared (TCCON) and mid-infrared (NDACC) measurements. Both TCCON and NDACC ne...
Published in: | Atmospheric Measurement Techniques |
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Online Access: | https://doi.org/10.5194/amt-12-1393-2019 https://amt.copernicus.org/articles/12/1393/2019/ |
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Nitrous oxide ( N 2 O ) is an important greenhouse gas and it can also generate nitric oxide, which depletes ozone in the stratosphere. It is a common target species of ground-based Fourier transform infrared (FTIR) near-infrared (TCCON) and mid-infrared (NDACC) measurements. Both TCCON and NDACC networks provide a long-term global distribution of atmospheric N 2 O mole fraction. In this study, the dry-air column-averaged mole fractions of N 2 O ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="7083feeaa337c360bc1dec6cdd9e436c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00001.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00001.png"/></svg:svg> ) from the TCCON and NDACC measurements are compared against each other at seven sites around the world (Ny-Ålesund, Sodankylä, Bremen, Izaña, Réunion, Wollongong, Lauder) in the time period of 2007–2017. The mean differences in <math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5e6a681c49fd20b61f27782a4f0ae370"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00002.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00002.png"/></svg:svg> between TCCON and NDACC (NDACC–TCCON) at these sites are between −3.32 and 1.37 ppb ( −1.1 %–0.5 %) with standard deviations between 1.69 and 5.01 ppb (0.5 %–1.6 %), which are within the uncertainties of the two datasets. The NDACC N 2 O retrieval has good sensitivity throughout the troposphere and stratosphere, while the TCCON retrieval underestimates a deviation from the a priori in the troposphere and overestimates it in the stratosphere. As a result, the TCCON <math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="50b5fa68b9780aad29d3bc59a335671d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00003.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00003.png"/></svg:svg> measurement is strongly affected by its a priori profile. Trends and seasonal cycles of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="99677be2b065f598f9fe943d745811ab"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00004.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00004.png"/></svg:svg> are derived from the TCCON and NDACC measurements and the nearby surface flask sample measurements and compared with the results from GEOS-Chem model a priori and a posteriori simulations. The trends and seasonal cycles from FTIR measurement at Ny-Ålesund and Sodankylä are strongly affected by the polar winter and the polar vortex. The a posteriori N 2 O fluxes in the model are optimized based on surface N 2 O measurements with a 4D-Var inversion method. The <math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="e10d4b76078a1e8806f098c6d853566d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00005.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00005.png"/></svg:svg> trends from the GEOS-Chem a posteriori simulation ( 0.97±0.02 ( 1 σ ) ppb yr −1 ) are close to those from the NDACC (0 .93±0.04 ppb yr −1 ) and the surface flask sample measurements ( 0.93±0.02 ppb yr −1 ). The <math xmlns="http://www.w3.org/1998/Math/MathML" id="M21" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="466b2088eb3ba38a6fcc0d0b8ea69279"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00006.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00006.png"/></svg:svg> trend from the TCCON measurements is slightly lower ( 0.81±0.04 ppb yr −1 ) due to the underestimation of the trend in TCCON a priori simulation. The <math xmlns="http://www.w3.org/1998/Math/MathML" id="M24" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="90450f00fd870e5f84133e6e1a36cf6c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00007.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00007.png"/></svg:svg> trends from the GEOS-Chem a priori simulation are about 1.25 ppb yr −1 , and our study confirms that the N 2 O fluxes from the a priori inventories are overestimated. The seasonal cycles of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M27" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="bf7b54d1602258a6bd4e0a2baf736945"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00008.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00008.png"/></svg:svg> from the FTIR measurements and the model simulations are close to each other in the Northern Hemisphere with a maximum in August–October and a minimum in February–April. However, in the Southern Hemisphere, the modeled <math xmlns="http://www.w3.org/1998/Math/MathML" id="M28" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="da6994d65f4a61e38d189bbe5fbdd62a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00009.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00009.png"/></svg:svg> values show a minimum in February–April while the FTIR <math xmlns="http://www.w3.org/1998/Math/MathML" id="M29" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="8900c9f9c19d990507a65d899d2e82ec"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00010.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00010.png"/></svg:svg> retrievals show different patterns. By comparing the partial column-averaged N 2 O from the model and NDACC for three vertical ranges (surface–8, 8–17, 17–50 km), we find that the discrepancy in the <math xmlns="http://www.w3.org/1998/Math/MathML" id="M31" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="0d208196834a80a82d174963af43b993"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00011.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00011.png"/></svg:svg> seasonal cycle between the model simulations and the FTIR measurements in the Southern Hemisphere is mainly due to their stratospheric differences. |
format |
Text |
author |
Zhou, Minqiang Langerock, Bavo Wells, Kelley C. Millet, Dylan B. Vigouroux, Corinne Sha, Mahesh Kumar Hermans, Christian Metzger, Jean-Marc Kivi, Rigel Heikkinen, Pauli Smale, Dan Pollard, David F. Jones, Nicholas Deutscher, Nicholas M. Blumenstock, Thomas Schneider, Matthias Palm, Mathias Notholt, Justus Hannigan, James W. Mazière, Martine |
spellingShingle |
Zhou, Minqiang Langerock, Bavo Wells, Kelley C. Millet, Dylan B. Vigouroux, Corinne Sha, Mahesh Kumar Hermans, Christian Metzger, Jean-Marc Kivi, Rigel Heikkinen, Pauli Smale, Dan Pollard, David F. Jones, Nicholas Deutscher, Nicholas M. Blumenstock, Thomas Schneider, Matthias Palm, Mathias Notholt, Justus Hannigan, James W. Mazière, Martine An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model |
author_facet |
Zhou, Minqiang Langerock, Bavo Wells, Kelley C. Millet, Dylan B. Vigouroux, Corinne Sha, Mahesh Kumar Hermans, Christian Metzger, Jean-Marc Kivi, Rigel Heikkinen, Pauli Smale, Dan Pollard, David F. Jones, Nicholas Deutscher, Nicholas M. Blumenstock, Thomas Schneider, Matthias Palm, Mathias Notholt, Justus Hannigan, James W. Mazière, Martine |
author_sort |
Zhou, Minqiang |
title |
An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model |
title_short |
An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model |
title_full |
An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model |
title_fullStr |
An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model |
title_full_unstemmed |
An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model |
title_sort |
intercomparison of total column-averaged nitrous oxide between ground-based ftir tccon and ndacc measurements at seven sites and comparisons with the geos-chem model |
publishDate |
2019 |
url |
https://doi.org/10.5194/amt-12-1393-2019 https://amt.copernicus.org/articles/12/1393/2019/ |
long_lat |
ENVELOPE(26.600,26.600,67.417,67.417) |
geographic |
Ny-Ålesund Sodankylä |
geographic_facet |
Ny-Ålesund Sodankylä |
genre |
Ny Ålesund Ny-Ålesund Sodankylä |
genre_facet |
Ny Ålesund Ny-Ålesund Sodankylä |
op_source |
eISSN: 1867-8548 |
op_relation |
doi:10.5194/amt-12-1393-2019 https://amt.copernicus.org/articles/12/1393/2019/ |
op_doi |
https://doi.org/10.5194/amt-12-1393-2019 |
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ftcopernicus:oai:publications.copernicus.org:amt71992 2023-05-15T17:48:29+02:00 An intercomparison of total column-averaged nitrous oxide between ground-based FTIR TCCON and NDACC measurements at seven sites and comparisons with the GEOS-Chem model Zhou, Minqiang Langerock, Bavo Wells, Kelley C. Millet, Dylan B. Vigouroux, Corinne Sha, Mahesh Kumar Hermans, Christian Metzger, Jean-Marc Kivi, Rigel Heikkinen, Pauli Smale, Dan Pollard, David F. Jones, Nicholas Deutscher, Nicholas M. Blumenstock, Thomas Schneider, Matthias Palm, Mathias Notholt, Justus Hannigan, James W. Mazière, Martine 2019-03-01 application/pdf https://doi.org/10.5194/amt-12-1393-2019 https://amt.copernicus.org/articles/12/1393/2019/ eng eng doi:10.5194/amt-12-1393-2019 https://amt.copernicus.org/articles/12/1393/2019/ eISSN: 1867-8548 Text 2019 ftcopernicus https://doi.org/10.5194/amt-12-1393-2019 2020-07-20T16:22:55Z Nitrous oxide ( N 2 O ) is an important greenhouse gas and it can also generate nitric oxide, which depletes ozone in the stratosphere. It is a common target species of ground-based Fourier transform infrared (FTIR) near-infrared (TCCON) and mid-infrared (NDACC) measurements. Both TCCON and NDACC networks provide a long-term global distribution of atmospheric N 2 O mole fraction. In this study, the dry-air column-averaged mole fractions of N 2 O ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="7083feeaa337c360bc1dec6cdd9e436c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00001.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00001.png"/></svg:svg> ) from the TCCON and NDACC measurements are compared against each other at seven sites around the world (Ny-Ålesund, Sodankylä, Bremen, Izaña, Réunion, Wollongong, Lauder) in the time period of 2007–2017. The mean differences in <math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5e6a681c49fd20b61f27782a4f0ae370"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00002.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00002.png"/></svg:svg> between TCCON and NDACC (NDACC–TCCON) at these sites are between −3.32 and 1.37 ppb ( −1.1 %–0.5 %) with standard deviations between 1.69 and 5.01 ppb (0.5 %–1.6 %), which are within the uncertainties of the two datasets. The NDACC N 2 O retrieval has good sensitivity throughout the troposphere and stratosphere, while the TCCON retrieval underestimates a deviation from the a priori in the troposphere and overestimates it in the stratosphere. As a result, the TCCON <math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="50b5fa68b9780aad29d3bc59a335671d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00003.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00003.png"/></svg:svg> measurement is strongly affected by its a priori profile. Trends and seasonal cycles of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="99677be2b065f598f9fe943d745811ab"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00004.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00004.png"/></svg:svg> are derived from the TCCON and NDACC measurements and the nearby surface flask sample measurements and compared with the results from GEOS-Chem model a priori and a posteriori simulations. The trends and seasonal cycles from FTIR measurement at Ny-Ålesund and Sodankylä are strongly affected by the polar winter and the polar vortex. The a posteriori N 2 O fluxes in the model are optimized based on surface N 2 O measurements with a 4D-Var inversion method. The <math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="e10d4b76078a1e8806f098c6d853566d"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00005.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00005.png"/></svg:svg> trends from the GEOS-Chem a posteriori simulation ( 0.97±0.02 ( 1 σ ) ppb yr −1 ) are close to those from the NDACC (0 .93±0.04 ppb yr −1 ) and the surface flask sample measurements ( 0.93±0.02 ppb yr −1 ). The <math xmlns="http://www.w3.org/1998/Math/MathML" id="M21" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="466b2088eb3ba38a6fcc0d0b8ea69279"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00006.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00006.png"/></svg:svg> trend from the TCCON measurements is slightly lower ( 0.81±0.04 ppb yr −1 ) due to the underestimation of the trend in TCCON a priori simulation. The <math xmlns="http://www.w3.org/1998/Math/MathML" id="M24" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="90450f00fd870e5f84133e6e1a36cf6c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00007.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00007.png"/></svg:svg> trends from the GEOS-Chem a priori simulation are about 1.25 ppb yr −1 , and our study confirms that the N 2 O fluxes from the a priori inventories are overestimated. The seasonal cycles of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M27" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="bf7b54d1602258a6bd4e0a2baf736945"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00008.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00008.png"/></svg:svg> from the FTIR measurements and the model simulations are close to each other in the Northern Hemisphere with a maximum in August–October and a minimum in February–April. However, in the Southern Hemisphere, the modeled <math xmlns="http://www.w3.org/1998/Math/MathML" id="M28" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="da6994d65f4a61e38d189bbe5fbdd62a"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00009.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00009.png"/></svg:svg> values show a minimum in February–April while the FTIR <math xmlns="http://www.w3.org/1998/Math/MathML" id="M29" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="8900c9f9c19d990507a65d899d2e82ec"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00010.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00010.png"/></svg:svg> retrievals show different patterns. By comparing the partial column-averaged N 2 O from the model and NDACC for three vertical ranges (surface–8, 8–17, 17–50 km), we find that the discrepancy in the <math xmlns="http://www.w3.org/1998/Math/MathML" id="M31" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msub><mi mathvariant="normal">X</mi><mrow><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub><mi mathvariant="normal">O</mi></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="0d208196834a80a82d174963af43b993"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-1393-2019-ie00011.svg" width="25pt" height="14pt" src="amt-12-1393-2019-ie00011.png"/></svg:svg> seasonal cycle between the model simulations and the FTIR measurements in the Southern Hemisphere is mainly due to their stratospheric differences. Text Ny Ålesund Ny-Ålesund Sodankylä Copernicus Publications: E-Journals Ny-Ålesund Sodankylä ENVELOPE(26.600,26.600,67.417,67.417) Atmospheric Measurement Techniques 12 2 1393 1408 |