Simulations of ⁷Be and ¹⁰Be with the GEOS-Chem global model v14.0.2 using state-of-the-art production rates

Abstract 7 Be and 10 Be are useful tracers for atmospheric transport studies. Combining 7 Be and 10 Be measurements with an atmospheric transport model can not only improve our understanding of the radionuclide transport and deposition processes but also provide an evaluation of the transport process in the model. To simulate these aerosol tracers, it is critical to evaluate the influence of radionuclide production uncertainties on simulations. Here we use the GEOS-Chem chemical transport model driven by the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) reanalysis to simulate 7 Be and 10 Be with the state-of-the-art production rate from the CRAC:Be (Cosmic Ray Atmospheric Cascade: Beryllium) model considering realistic spatial geomagnetic cutoff rigidities (denoted as P16spa). We also perform two sensitivity simulations: one with the default production rate in GEOS-Chem based on an empirical approach (denoted as LP67) and the other with the production rate from the CRAC:Be but considering only geomagnetic cutoff rigidities for a geocentric axial dipole (denoted as P16). The model results are comprehensively evaluated with a large number of measurements including surface air concentrations and deposition fluxes. The simulation with the P16spa production can reproduce the absolute values and temporal variability of 7 Be and 10 Be surface concentrations and deposition fluxes on annual and sub-annual scales, as well as the vertical profiles of air concentrations. The simulation with the LP67 production tends to overestimate the absolute values of 7 Be and 10 Be concentrations. The P16 simulation suggests less than 10 % differences compared to P16spa but a significant positive bias (∼ 18  %) in the 7 Be deposition fluxes over East Asia. We find that the deposition fluxes are more sensitive to the production in the troposphere and downward transport from the stratosphere. Independent of the production models, surface air concentrations and deposition fluxes from all simulations show similar seasonal variations, suggesting a dominant meteorological influence. The model can also reasonably simulate the stratosphere–troposphere exchange process of 7 Be and 10 Be by producing stratospheric contribution and 10 Be/7 Be ratio values that agree with measurements. Finally, we illustrate the importance of including the time-varying solar modulations in the production calculation, which significantly improve the agreement between model results and measurements, especially at mid-latitudes and high latitudes. Reduced uncertainties in the production rates, as demonstrated in this study, improve the utility of 7 Be and 10 Be as aerosol tracers for evaluating and testing transport and scavenging processes in global models. For future GEOS-Chem simulations of 7 Be and 10 Be, we recommend using the P16spa (versus default LP67) production rate.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Simulations of ⁷Be and ¹⁰Be with the GEOS-Chem global model v14.0.2 using state-of-the-art production rates ; volume:16 ; number:23 ; year:2023 ; pages:7037-7057 ; extent:21 ; Geoscientific model development ; 16, Heft 23 (2023), 7037-7057 (gesamt 21)

Contributors, Places and Time

• Creator: Zheng, Minjie ; Liu, Hongyu ; Adolphi, Florian ; Muscheler, Raimund ; Lu, Zhengyao ; Wu, Mousong ; Prisle, Nønne L.

Further information

• DOI: 10.5194/gmd-16-7037-2023
• URN: urn:nbn:de:101:1-2023120703351173055203
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:35 AM CEST