EGU21-2298
https://doi.org/10.5194/egusphere-egu21-2298
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evaluation of CAM-Chem VSLBr model performance during SouthTRAC campaign

Lucas Berná1, Ana Isabel Lopez-Noreña1,2,3, Enrique Puliafito1,2, Javier Alejandro Barrera2, Andreas Engel4, Markus Jesswein4, Carlos Alberto Cuevas5, Alfonso Saiz-Lopez5, and Rafael Pedro Fernandez2,3,6
Lucas Berná et al.
  • 1National University of Technology - Argentina, GEAA, CEDS, Mendoza, Argentina (lberna@mendoza-conicet.gob.ar)
  • 2National Scientific and Technical Research Council (CONICET), Mendoza, 5501, Argentina
  • 3School of Natural Sciences, National University of Cuyo (FCEN-UNCuyo), Mendoza, 5501, Argentina
  • 4Institute for Atmospheric and Environmental Science, Goethe University Frankfurt, Frankfurt, Germany
  • 5Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, 28006, Spain
  • 6Institute for Interdisciplinary Science, National Research Council (ICB-CONICET), Mendoza, 5501, Argentina

In the framework of the SouthTRAC Campaign (Transport and Composition of the Southern Hemisphere Upper Troposphere and Lower Stratosphere) based on Rio Grande, Argentina, a local research group from CONICET (Argentine National Research Council)  joined the German consortium maintaining the HALO research aircraft (High-Altitude and LOng-range aircraft)  to help with the flight planning and evaluation of the chemical composition of the upper troposphere and lower stratosphere within the ozone hole periphery. The SouthTRAC aircraft campaign was carried out in two phases which took place in September and November 2019, respectively. With the purpose of providing additional information of the atmospheric composition of brominated Very Short-Lived (VSLBr) species and compare with HALO observations during the transfer and campaign flights, a CAM-Chem (Community Atmosphere Model with Chemistry) global chemistry-climate simulation was conducted. The model setup used in the halogenated CAM-Chem simulation had a 1° x 1.25° lat-lon resolution, 56 hybrid vertical levels from the surface to the middle stratosphere and considered assimilated meteorology from MERRA, including an explicit treatment of VSLBr sources and chemistry. Model output of VSLBr, long-lived bromine and chlorine (LLBr and LLCl) species and ozone mixing ratios, as well as the main inorganic halogen reactive and reservoir species and gas/heterogeneous phase reaction rates affecting lowermost stratospheric ozone were analyzed in horizontal domains and vertical cross-sections across each flightpath. The model performance with respect to the HALO observations has a general good agreement, presenting better results for mid latitudes (between 30º S and 50º S) than for southern latitudes (>50º S). In particular, CAM-Chem timeseries consistently reproduced the spatio-temporal variation of the main VSLBr species (CH2Br2 and CHBr3), including the sharp variations observed across the tropopause. For both VSLBr as well as for LLCl compounds such as CFC-12, the Pearson correlation coefficient r obtained during each of the flights ranged between 0.7 and 0.9, while the Normalized Mean Bias (NMB) was smaller than 8% for almost every flight. Regarding LLBr CH3Br, the correlation with the aircraft observations is high (r>0.9) but the inter-hemispheric variability during transfer flights is not fully captured. For Ozone, the model presents mid to high correlation with respect to measures (0.5<r<0.95) with a variable overestimation ranging from 10% to at most 40% in some flights.

How to cite: Berná, L., Lopez-Noreña, A. I., Puliafito, E., Barrera, J. A., Engel, A., Jesswein, M., Cuevas, C. A., Saiz-Lopez, A., and Fernandez, R. P.: Evaluation of CAM-Chem VSLBr model performance during SouthTRAC campaign, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2298, https://doi.org/10.5194/egusphere-egu21-2298, 2021.

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