Stratospheric Injection of Brominated Very Short‐Lived Substances: Aircraft Observations in the Western Pacific and Representation in Global Models

Wales, Pamela; Salawitch, R. J.; Nicely, Julie M.; Anderson, Daniel C.; Canty, T. P.; Baidar, Sunil; Dix, B.; Koenig, Theodore K.; Volkamer, Rainer; Chen, Dexian; Huey, L. G.; Tanner, David J.; Cuevas, Carlos A.; Fernández, Rafael P.; Kinnison, Douglas E.; Lamarque, J. F.; Saiz‐Lopez, Alfonso; Atlas, Elliot L.; Hall, Samuel R.; Navarro, María Amparo Gilabert; Pan, Laura L.; Schauffler, S.; Stell, Meghan; Tilmes, Simone; Ullmann, Kirk; Weinheimer, A. J.; Akiyoshi, Hideharu; Chipperfield, Martyn; Deushi, Makoto; Dhomse, Sandip; Feng, Wuhu; Graf, Phoebe; Hossaini, Ryan; Jöckel, Patrick; Mancini, E.; Michou, Martine; Morgenstern, Olaf; Oman, Luke D.; Pitari, Giovanni; Plummer, David A.; Revell, Laura E.; Rozanov, Eugene; Saint‐Martin, David; Schofield, Robyn; Stenke, Andrea; Stone, Kane; Visioni, Daniele; Yamashita, Yousuke; Zeng, Guang

doi:10.1029/2017jd027978

Cited by 45 publications

(92 citation statements)

References 155 publications

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“…The atmospheric chemistry scheme of CNRM‐ESM2‐1 is Reactive Processes Ruling the Ozone Budget in the Stratosphere Version 2 (REPROBUS‐C_v2), first implemented and evaluated in a former version of CNRM climate model (Michou et al, ), and more recently during the course of the Chemistry Climate Model Initiative (CCMI) research (e.g., Maycock, Matthes, et al, ; Maycock, Randel, et al, ; Morgenstern et al, ; Wales et al, ; Zhang et al, ). It is an “online” scheme whereby the chemistry routines are part of the physics of the atmospheric climate model and called at each time step of the physics.…”

Section: Cnrm‐esm2‐1 Componentsmentioning

confidence: 99%

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Séférian

Nabat

Michou

et al. 2019

J Adv Model Earth Syst

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This study introduces CNRM-ESM2-1, the Earth system (ES) model of second generation developed by CNRM-CERFACS for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). CNRM-ESM2-1 offers a higher model complexity than the Atmosphere-Ocean General Circulation Model CNRM-CM6-1 by adding interactive ES components such as carbon cycle, aerosols, and atmospheric chemistry. As both models share the same code, physical parameterizations, and grid resolution, they offer a fully traceable framework to investigate how far the represented ES processes impact the model performance over present-day, response to external forcing and future climate projections. Using a large variety of CMIP6 experiments, we show that represented ES processes impact more prominently the model response to external forcing than the model performance over present-day. Both models display comparable performance at replicating modern observations although the mean climate of CNRM-ESM2-1 is slightly warmer than that of CNRM-CM6-1. This difference arises from land cover-aerosol interactions where the use of different soil vegetation distributions between both models impacts the rate of dust emissions. This interaction results in a smaller aerosol burden in CNRM-ESM2-1 than in CNRM-CM6-1, leading to a different surface radiative budget and climate. Greater differences are found when comparing the model response to external forcing and future climate projections. Represented ES processes damp future warming by up to 10% in CNRM-ESM2-1 with respect to CNRM-CM6-1. The representation of land vegetation and the CO 2 -water-stomatal feedback between both models explain about 60% of this difference. The remainder is driven by other ES feedbacks such as the natural aerosol feedback.

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Section: Cnrm‐esm2‐1 Componentsmentioning

confidence: 99%

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Séférian

Nabat

Michou

et al. 2019

J Adv Model Earth Syst

Self Cite

428

167

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“…The version of the stratospheric model employed here was recently used by Chipperfield et al (2018) to investigate lower stratospheric ozone trends and is used by Harrison et al (2018) to interpret long-term COCl 2 observations from ACE. It has also been extensively evaluated in terms of both chemistry and transport (e.g., Harrison et al, 2016;Wales et al, 2018). Figure 6 compares the modeled upper stratospheric HCl time series (60°S-60°N) to that observed by ACE.…”

Section: Journal Of Geophysical Research: Atmospheresmentioning

confidence: 99%

“…Over the past decade it has become clear that (a) natural brominated VSLS (e.g., CHBr 3 ) are a significant source of stratospheric bromine (e.g., Sala et al, 2014;Salawitch et al, 2005;Sturges et al, 2000;Wales et al, 2018), and (b) chlorinated VSLS (Cl-VSLS) are a small, but potentially increasing, source of stratospheric chlorine (Hossaini et al, 2015b). CH 2 Cl 2 is the most abundant Cl-VSLS and its tropospheric abundance has increased approximately twofold since the early 2000s.…”

Section: Introductionmentioning

confidence: 99%

Recent Trends in Stratospheric Chlorine From Very Short‐Lived Substances

et al. 2019

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Very short‐lived substances (VSLS), including dichloromethane (CH 2 Cl 2 ), chloroform (CHCl 3 ), perchloroethylene (C 2 Cl 4 ), and 1,2‐dichloroethane (C 2 H 4 Cl 2 ), are a stratospheric chlorine source and therefore contribute to ozone depletion. We quantify stratospheric chlorine trends from these VSLS (VSLCl tot ) using a chemical transport model and atmospheric measurements, including novel high‐altitude aircraft data from the NASA VIRGAS (2015) and POSIDON (2016) missions. We estimate VSLCl tot increased from 69 (±14) parts per trillion (ppt) Cl in 2000 to 111 (±22) ppt Cl in 2017, with >80% delivered to the stratosphere through source gas injection, and the remainder from product gases. The modeled evolution of chlorine source gas injection agrees well with historical aircraft data, which corroborate reported surface CH 2 Cl 2 increases since the mid‐2000s. The relative contribution of VSLS to total stratospheric chlorine increased from ~2% in 2000 to ~3.4% in 2017, reflecting both VSLS growth and decreases in long‐lived halocarbons. We derive a mean VSLCl tot growth rate of 3.8 (±0.3) ppt Cl/year between 2004 and 2017, though year‐to‐year growth rates are variable and were small or negative in the period 2015–2017. Whether this is a transient effect, or longer‐term stabilization, requires monitoring. In the upper stratosphere, the modeled rate of HCl decline (2004–2017) is −5.2% per decade with VSLS included, in good agreement to ACE satellite data (−4.8% per decade), and 15% slower than a model simulation without VSLS. Thus, VSLS have offset a portion of stratospheric chlorine reductions since the mid‐2000s.

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“…The chemistry scheme of CNRM‐ESM2‐1, identified in CMIP6 simulations under the name REPROBUS‐C_v2, was implemented in the CNRM climate model and evaluated in Michou et al (). This climate model version also contributed to the Chemistry Climate Model Initiative (e.g., Maycock, Matthes, et al, ; Maycock, Randel, et al, ; Morgenstern et al, ; Wales et al, ; Zhang et al, ). It is an “online” scheme whereby the chemistry routines are part of the physics of the atmospheric climate model and called at each time step of the physics.…”

Section: Methodsmentioning

confidence: 99%

Present‐Day and Historical Aerosol and Ozone Characteristics in CNRM CMIP6 Simulations

Michou

Nabat

Saint‐Martin

et al. 2020

J Adv Model Earth Syst

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Characteristics and radiative forcing of the aerosol and ozone fields of two configurations of the Centre National de Recherches Météoroglogiques (CNRM) and Cerfacs climate model are analyzed over the historical period (1850-2014), using several Coupled Model Intercomparison Project 6 (CMIP6) simulations. CNRM-CM6-1 is the atmosphere-ocean general circulation model including prescribed aerosols and a linear stratospheric ozone scheme, while the Earth System Model CNRM-ESM2-1 has interactive tropospheric aerosols and chemistry of the midtroposphere aloft. The representations of aerosols and ozone in CNRM-CM6-1 are issued from simulations of CNRM-ESM2-1, and this ensures some comparability of both representations. In particular, present-day anthropogenic aerosol optical depths are similar (0.018), and their spatial patterns correspond to those of reference data sets such as MACv2 and MACv2-SP despite a negative bias. Effective radiative forcings (ERFs) have been estimated using 30-year fixed sea surface temperature simulations (piClim) and several calls to the radiative scheme. Present-day anthropogenic aerosol ERF, aerosol-radiation ERF, and aerosol cloud ERF are fully within CMIP5 estimates and, respectively, equal to −1.10, −0.36, and −0.81 W m −2 for CNRM-CM6-1 and −0.21, −0.61, and −0.74 W m −2 for CNRM-ESM2-1. Additional CMIP6-type piClim simulations show that these differences are mainly due to the interactivity of the aerosol scheme whose impact is confirmed when assessing the response of both climate model configurations to rising CO 2 . Present-day stratospheric ozone ERF, equal to −0.04 W m −2 , is in agreement with that of the CMIP6 ozone. No trend appears in the ozone ERF over the historical period although the evolution of the total column ozone is correctly simulated. Plain Language SummaryThe manuscript documents the Météo-France Centre National de Recherches Météorologiques aerosol-chemistry modeling contributions to the sixth Coupled Model Intercomparison Project that supports the sixth IPCC Assessment Report of climate change. It establishes that their results are suitable for use by the scientific community in the analysis of the sixth Coupled Model Intercomparison Project experiments. The authors provide an evaluation of the model performance in both present-day and historical (1850-2014) contexts, as well as a detailed analysis of the model calculated effective radiative forcing due to ozone and aerosols.

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Stratospheric Injection of Brominated Very Short‐Lived Substances: Aircraft Observations in the Western Pacific and Representation in Global Models

Cited by 45 publications

References 155 publications

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Recent Trends in Stratospheric Chlorine From Very Short‐Lived Substances

Present‐Day and Historical Aerosol and Ozone Characteristics in CNRM CMIP6 Simulations

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