This is the primary data for a article going to be submitted to AGU GRL, named “contributions of Arctic sea-ice loss and East Siberian atmospheric blocking to 2020 record-breaking Meiyu-Baiu rainfall”. We conducted atmospheric modeling experiments using the Community Atmosphere Model version 6 (CAM6), in the Community Earth System Model, version 2 (CESM2, Danabasoglu et al. 2020) from the National Center for Atmospheric Research (NCAR). The CAM6 was run with 1.25lon*0.9lat horizontal spacing, 32 vertical levels from the surface to 2.26 hPa. In the control experiment (CTL), 1995-2005 monthly climatological SST and SIC were used as the lower boundary condition and run for 75 years, including a 25-year spin-up. To examine the influence of Arctic sea ice anomalies, we further ran two perturbed experiments covering only the period from April 1st to July 31st. In the first perturbation experiment (ARCTIC), SST and SIC north of 65 were fixed to those of 2020 from May to July and to the climatology for April. The other perturbation experiment (GLOBAL) is the same as ARCTIC except it used the 2020 SST and SIC over the globe from May to July. We performed 20 ensemble simulations with slightly different initial conditions for each of the 4-month perturbation experiments and used their ensemble mean to reduce the internal variabilities. The GLOBAL-minus-CTL differences represent the atmospheric response to the SST and SIC anomalies in late spring-early summer of 2020, and the ARCTIC-minus-CTL differences represent the atmospheric response to the Arctic SIC and SST anomalies in late spring-early summer of 2020.
“2020mjjsic” denotes the ARCTIC experiment, “globalsst” denotes the GLOBAL experiment, and “ctrl_climatology” denotes the ensemble mean of CTL experiment.
Danabasoglu, G., Lamarque, J. F., Bacmeister, J., Bailey, D. A., DuVivier, A. K., Edwards, J., et al. (2020). The Community Earth System Model Version 2 (CESM2). Journal of Advances in Modeling Earth Systems,12, e2019MS001916.
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