Changes between Version 1 and Version 2 of GroupActivities/CodeAvalaibilityPublication/ORCHIDEE_COS_JGR


Ignore:
Timestamp:
2023-01-13T11:23:40+01:00 (18 months ago)
Author:
maignan
Comment:

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  • GroupActivities/CodeAvalaibilityPublication/ORCHIDEE_COS_JGR

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    11= ORCHIDEE_COS_JGR = 
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    3 This version of ORCHIDEE has been used in publication "Intercomparison of atmospheric Carbonyl Sulfide (TransCom-COS; Part one): Evaluating the impact of transport and emissions on tropospheric variability using ground-based and aircraft data" by Remaud et al. (2023)  
     3This version of ORCHIDEE has been used in publication "Intercomparison of atmospheric Carbonyl Sulfide (!TransCom-COS; Part one): Evaluating the impact of transport and emissions on tropospheric variability using ground-based and aircraft data" by Remaud et al. (2023)  
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    55== Abstract == 
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    7 We present a comparison of atmospheric transport model simulations for carbonyl sulfide (COS), within the framework of the ongoing atmospheric tracer transport model intercomparison project “TransCom”. Seven atmospheric transport models participated in the inter-comparison experiment and provided simulations of COS mixing ratios in the troposphere over a 9-year period (2010–2018), using prescribed state-of-the-art surface fluxes for various components of the atmospheric COS budget: biospheric sink, oceanic source, sources from fire and industry. Since the biosphere is the largest sink of COS, we tested sink estimates produced by two different biosphere models. The main goals of TransCom-COS are (a) to investigate the impact of the transport uncertainty and emission distribution in simulating the spatio-temporal variability of COS mixing ratios in the troposphere, and (b) to assess the sensitivity of simulated tropospheric COS mixing ratios to the seasonal and diurnal variability of the COS biosphere fluxes. To this end, a control case with state-of-the-art seasonal fluxes of COS was constructed. Models were run with the same fluxes and without chemistry to isolate transport differences. Further, two COS flux scenarios were compared: one using a biosphere flux with a monthly time resolution and the other using a biosphere flux with a three-hourly time resolution. In addition, we investigated the sensitivity of the simulated concentrations to different biosphere fluxes and to indirect oceanic emissions through dimethylsulfide (DMS) and carbon disulfide (CS2). The modelled COS mixing ratios were assessed against in-situ observations from surface stations and aircraft. 
     7We present a comparison of atmospheric transport model simulations for carbonyl sulfide (COS), within the framework of the ongoing atmospheric tracer transport model intercomparison project “!TransCom”. Seven atmospheric transport models participated in the inter-comparison experiment and provided simulations of COS mixing ratios in the troposphere over a 9-year period (2010–2018), using prescribed state-of-the-art surface fluxes for various components of the atmospheric COS budget: biospheric sink, oceanic source, sources from fire and industry. Since the biosphere is the largest sink of COS, we tested sink estimates produced by two different biosphere models. The main goals of !TransCom-COS are (a) to investigate the impact of the transport uncertainty and emission distribution in simulating the spatio-temporal variability of COS mixing ratios in the troposphere, and (b) to assess the sensitivity of simulated tropospheric COS mixing ratios to the seasonal and diurnal variability of the COS biosphere fluxes. To this end, a control case with state-of-the-art seasonal fluxes of COS was constructed. Models were run with the same fluxes and without chemistry to isolate transport differences. Further, two COS flux scenarios were compared: one using a biosphere flux with a monthly time resolution and the other using a biosphere flux with a three-hourly time resolution. In addition, we investigated the sensitivity of the simulated concentrations to different biosphere fluxes and to indirect oceanic emissions through dimethylsulfide (DMS) and carbon disulfide (CS2). The modelled COS mixing ratios were assessed against in-situ observations from surface stations and aircraft. 
    88The results indicate that all models fail to capture the observed latitudinal distribution of COS at the surface. The COS mixing ratios are underestimated by at least 50 parts per trillion (ppt) in the tropics, pointing to a missing tropical source. In contrast, in summer the mixing ratios are overestimated by at least 50 ppt above 40oN, pointing to a likely missing sink in the high northern latitudes during the summer. The seasonal variability and the latitudinal distribution of COS surface mixing ratios are more sensitive to the transport model used than to a change in biosphere fluxes. Regarding the seasonal mean latitudinal profiles, in the vicinity of anthropogenic sources, the spread between models is greater than 60 ppt above 40oN in boreal summer. Regarding the seasonal amplitude, the model spread reaches 50 ppt at 6 out of 15 sites, compared to an observed seasonal amplitude of 100 ppt. All models simulated a too late minimum by at least 2 to 3 months at two high northern-latitude sites, likely owing to errors in the seasonal cycle in the ocean emissions. Finally, the temporal resolution of the biosphere fluxes (monthly versus three-hourly) has a relatively small impact of less than 20 ppt (compared to model spread) on the mean seasonal cycle at surface stations. 
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