Here we provide essential codes and data used and published in publications supproted by the following project

Project
NSF: A High-sensitivity Beryllium-10 Record from an Ice Core at South Pole

(1443144, PI: Eric Steig, Co-PI: Qinghua Ding, 2016-2020)

Data:

    All following five experiments were conducted using ECHAM5-HAM atmospheric aerosol - climate model (developed by U. Heikkila) at horizontal resolution of T42 (~2.8 latitude * 2.8 longitude) with 19 vertical levels, and the temporal resolution of 30-min. Daily averages of 30-min outputs in these simulations are stored on Ding's local data archive and monthly averages of daily values are available for download.


    Exp 1. Monthly 10Be deposition and some key atmospheric variables in an AMIP simulation conducted by Ding, Steig and Schaefer
    This AMIP type simulation is forced by observed SST/sea ice from 1956 to 2011. All external forcings including 10be production rate in this simulation are set at constant values. SST and sea ice boundary forcing is derived from AMIP II Sea Surface Temperature and Sea Ice Concentration Boundary Conditions ( https://pcmdi.llnl.gov/mips/amip/amip2/AMIP2EXPDSN/BCS/amip2bcs.html). The input of 10be production rate, calculated from the Masarik and Beer (1999) for a geomagnetic field strength = 0, is long term average over the whole period. All greenhouse gas concentrations (including CO2, CH4, N2O and CFC ) are set at the level of year 1987. The goal of this experiment is to assess the sensitivity of simulated 10be in the Antarctic to interannual and interdecadal boundary forcing over the past 6 decades. These data will be used and repored in our new group paper focusing a comparison of simulated 10be with new 10be records over South Pole measured by Schaefer.

    Exp 2. Monthly 10Be deposition and some key atmospheric variables in a control simulation conducted by Ding, Steig and Schaefer
    This control simulation is forced by climatological AMIPII SST/sea ice ( https://pcmdi.llnl.gov/mips/amip/amip2/AMIP2EXPDSN/BCS/amip2bcs.html ) averaged over the whole period from 1956 to 2011 and constant external forcings ( at the level of year 1987) for 51 years. The 10be production rate in this simulation is adapted from Masarik and Beer (1999) (for a geomagnetic field strength = 0) from 1956 to 2006. The goal of this experiment is to assess the sensitivity of simulated 10be in the Antarctic to historical 10be production rate changes. These data will be used and repored in our new group paper focusing a comparison of simulated 10be with new 10be records over South Pole measured by Schaefer.

    Exp 3. Monthly 10Be deposition and some key atmospheric variables in an AMIP-type simulation forced by present-day (0ka) climate conditions derived from TraCE-21ka.
    This simulation is forced by long term average of SST/sea ice derived from TraCE-21ka's (https://www.cgd.ucar.edu/ccr/TraCE/) present-day conditions for 50 years (the first 25 years are dropped as a spin-up). The 10be production rate is set at the values of year 2000 derived from Masarik and Beer (1999) (for a geomagnetic field strength = 0). The goal of this experiment is to assess the sensitivity of simulated 10be in the Antarctic to climate forcing on millennial time scales.

    Exp 4. Monthly 10Be deposition and some key atmospheric variables in an AMIP-type simulation forced by 6ka climate conditions derived from TraCE-21ka.
    This simulation is forced by long term average of SST/sea ice derived from TraCE-21ka's (https://www.cgd.ucar.edu/ccr/TraCE/) 6ka conditions for 50 years (the first 25 years are dropped as a spin-up). The 10be production rate is set at the values of year 2000 derived from Masarik and Beer (1999) (for a geomagnetic field strength = 0). The goal of this experiment is to assess the sensitivity of simulated 10be in the Antarctic to climate forcing on millennial time scales.

    Exp 5. Monthly 10Be deposition and some key atmospheric variables in an AMIP-type simulation forced by 21ka climate conditions derived from TraCE-21ka.
    This simulation is forced by long term average of SST/sea ice derived from TraCE-21ka's (https://www.cgd.ucar.edu/ccr/TraCE/) 21ka conditions for 50 years (the first 25 years are dropped as a spin-up). The 10be production rate is set at the values of year 2000 derived from Masarik and Beer (1999) (for a geomagnetic field strength = 0). The goal of this experiment is to assess the sensitivity of simulated 10be in the Antarctic to climate forcing on millennial time scales.

      Source Code:

        Fortran source codes of ECHAM5-HAM atmospheric aerosol - climate model developed by U. Heikkila
        Please read Heikkila et al. 2013 ("10Be in late deglacial climate simulated by ECHAM5-HAM - Part 1: Climatological influences on 10Be deposition", Clim. Past, 9, 2641-2649, 2013) for more details of the model

          Publications:

            1. Ding, Q. and Q. Fu. A warming tropical central Pacific dries the lower stratosphere. Climate Dynamics, doi:10.1007/s00382-017-3774-y (2018).
            2. Feng, X., Ding, Q., Wu, L., Jones, C., Baxter, I., Tardif, R., Stevenson, S., Emile-Geay, J., Mitchell, J., Carvalho, L. M. V., Wang, H., and Steig, E.. A multidecadal-scale tropically-driven global teleconnection over the past millennium and its recent strengthening. J. Climate, (2021)