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Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate

We have compared a suite of recent global CO(2) atmospheric inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterio...

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Autores principales: Gaubert, Benjamin, Stephens, Britton B., Basu, Sourish, Chevallier, Frédéric, Deng, Feng, Kort, Eric A., Patra, Prabir K., Peters, Wouter, Rödenbeck, Christian, Saeki, Tazu, Schimel, David, Van der Laan-Luijkx, Ingrid, Wofsy, Steven, Yin, Yi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6839691/
https://www.ncbi.nlm.nih.gov/pubmed/31708981
http://dx.doi.org/10.5194/bg-16-117-2019
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author Gaubert, Benjamin
Stephens, Britton B.
Basu, Sourish
Chevallier, Frédéric
Deng, Feng
Kort, Eric A.
Patra, Prabir K.
Peters, Wouter
Rödenbeck, Christian
Saeki, Tazu
Schimel, David
Van der Laan-Luijkx, Ingrid
Wofsy, Steven
Yin, Yi
author_facet Gaubert, Benjamin
Stephens, Britton B.
Basu, Sourish
Chevallier, Frédéric
Deng, Feng
Kort, Eric A.
Patra, Prabir K.
Peters, Wouter
Rödenbeck, Christian
Saeki, Tazu
Schimel, David
Van der Laan-Luijkx, Ingrid
Wofsy, Steven
Yin, Yi
author_sort Gaubert, Benjamin
collection PubMed
description We have compared a suite of recent global CO(2) atmospheric inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO(2) concentration profiles against observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) aircraft campaigns over the mid-Pacific in 2009–2011. Although the models differ in inverse approaches, assimilated observations, prior fluxes, and transport models, their broad latitudinal separation of land fluxes has converged significantly since the Atmospheric Carbon Cycle Inversion Intercomparison (TransCom 3) and the REgional Carbon Cycle Assessment and Processes (RECCAP) projects, with model spread reduced by 80% since TransCom 3 and 70% since RECCAP. Most modeled CO(2) fields agree reasonably well with the HIPPO observations, specifically for the annual mean vertical gradients in the Northern Hemisphere. Northern Hemisphere vertical mixing no longer appears to be a dominant driver of northern versus tropical (T) annual flux differences. Our newer suite of models still gives northern extratropical land uptake that is modest relative to previous estimates (Gurney et al., 2002; Peylin et al., 2013) and near-neutral tropical land uptake for 2009–2011. Given estimates of emissions from deforestation, this implies a continued uptake in intact tropical forests that is strong relative to historical estimates (Gurney et al., 2002; Peylin et al., 2013). The results from these models for other time periods (2004–2014, 2001–2004, 1992–1996) and reevaluation of the TransCom 3 Level 2 and RECCAP results confirm that tropical land carbon fluxes including deforestation have been near neutral for several decades. However, models still have large disagreements on ocean–land partitioning. The fossil fuel (FF) and the atmospheric growth rate terms have been thought to be the best-known terms in the global carbon budget, but we show that they currently limit our ability to assess regional-scale terrestrial fluxes and ocean–land partitioning from the model ensemble.
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spelling pubmed-68396912020-01-16 Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate Gaubert, Benjamin Stephens, Britton B. Basu, Sourish Chevallier, Frédéric Deng, Feng Kort, Eric A. Patra, Prabir K. Peters, Wouter Rödenbeck, Christian Saeki, Tazu Schimel, David Van der Laan-Luijkx, Ingrid Wofsy, Steven Yin, Yi Biogeosciences Article We have compared a suite of recent global CO(2) atmospheric inversion results to independent airborne observations and to each other, to assess their dependence on differences in northern extratropical (NET) vertical transport and to identify some of the drivers of model spread. We evaluate posterior CO(2) concentration profiles against observations from the High-Performance Instrumented Airborne Platform for Environmental Research (HIAPER) Pole-to-Pole Observations (HIPPO) aircraft campaigns over the mid-Pacific in 2009–2011. Although the models differ in inverse approaches, assimilated observations, prior fluxes, and transport models, their broad latitudinal separation of land fluxes has converged significantly since the Atmospheric Carbon Cycle Inversion Intercomparison (TransCom 3) and the REgional Carbon Cycle Assessment and Processes (RECCAP) projects, with model spread reduced by 80% since TransCom 3 and 70% since RECCAP. Most modeled CO(2) fields agree reasonably well with the HIPPO observations, specifically for the annual mean vertical gradients in the Northern Hemisphere. Northern Hemisphere vertical mixing no longer appears to be a dominant driver of northern versus tropical (T) annual flux differences. Our newer suite of models still gives northern extratropical land uptake that is modest relative to previous estimates (Gurney et al., 2002; Peylin et al., 2013) and near-neutral tropical land uptake for 2009–2011. Given estimates of emissions from deforestation, this implies a continued uptake in intact tropical forests that is strong relative to historical estimates (Gurney et al., 2002; Peylin et al., 2013). The results from these models for other time periods (2004–2014, 2001–2004, 1992–1996) and reevaluation of the TransCom 3 Level 2 and RECCAP results confirm that tropical land carbon fluxes including deforestation have been near neutral for several decades. However, models still have large disagreements on ocean–land partitioning. The fossil fuel (FF) and the atmospheric growth rate terms have been thought to be the best-known terms in the global carbon budget, but we show that they currently limit our ability to assess regional-scale terrestrial fluxes and ocean–land partitioning from the model ensemble. 2019-01-16 2019 /pmc/articles/PMC6839691/ /pubmed/31708981 http://dx.doi.org/10.5194/bg-16-117-2019 Text en This work is distributed under the Creative Commons Attribution 4.0 License. http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Gaubert, Benjamin
Stephens, Britton B.
Basu, Sourish
Chevallier, Frédéric
Deng, Feng
Kort, Eric A.
Patra, Prabir K.
Peters, Wouter
Rödenbeck, Christian
Saeki, Tazu
Schimel, David
Van der Laan-Luijkx, Ingrid
Wofsy, Steven
Yin, Yi
Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate
title Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate
title_full Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate
title_fullStr Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate
title_full_unstemmed Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate
title_short Global atmospheric CO(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate
title_sort global atmospheric co(2) inverse models converging on neutral tropical land exchange, but disagreeing on fossil fuel and atmospheric growth rate
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6839691/
https://www.ncbi.nlm.nih.gov/pubmed/31708981
http://dx.doi.org/10.5194/bg-16-117-2019
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