Icon NARVAL simulation over the tropical Atlantic for the ATL, BAR and AMA subdomains, the simulation day is 2013-12-01, extracted from NARVAL1 simulations

Icon 2.5 km simulations over the tropical Atlantic ([65 W:15E],[10S:20N] for the months of December 2013 (NARVAL1: 30 days) and August 2016 (NARVAL2: 30 days). The grid spacing, computed as the square root of the triangular grid cells, amounts to 2.5 km. In the vertical, a stretched vertical coordinate is used with 75 layers, whereby 12 layers are located in the first kilometer. The simulations are conducted for the months of December 2013 and July 2016. They are started every day at 00 UTC from the analysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) and integrated for 36 hours. Boundary data are taken from the ECMWF forecasts and updated every 3 hours. At the bottom boundary, the Sea Surface Temperature (SST) is taken from the ECMWF analysis. It is kept fixed at its initial value during the 36-h integration period. The simulations were conducted using the ICOsahedral Non-hydrostatic (ICON) model (Zängl et al., 2015). Given the horizontal grid spacing, no convective Parameterisation is employed and convection is explicitly resolved by the bulk Microphysics scheme that predicts cloud water, rain, snow, ice and Graupel (Baldauf et al., 2011). The parameterisationations for gravity wave drag and subgrid-scale orography are also switched off, otherwise the model employs the same parameterisationations as the operational model version in use at the German Weather Service (DWD), see Zängl et al. (2015) and Klocke et al. (2017) for further details.针对热带大西洋海域（范围为西经65°至东经15°、南纬10°至北纬20°）开展的2.5千米分辨率模拟试验，模拟时段为2013年12月（NARVAL1项目，共30天）与2016年8月（NARVAL2项目，共30天）。网格间距取三角形网格单元面积的平方根，最终为2.5千米。垂直方向采用拉伸垂直坐标，共75层，其中12层分布于近地面1千米高度范围内。本次模拟的运行时段为2013年12月与2016年7月，每日协调世界时（Coordinated Universal Time, UTC）00时以欧洲中期天气预报中心（European Centre for Medium-Range Weather Forecasts, ECMWF）的分析场作为初始场启动，积分时长为36小时。边界条件数据取自ECMWF的预报场，每3小时更新一次。下边界的海表温度（Sea Surface Temperature, SST）取自ECMWF分析场，在36小时的积分时段内保持初始值固定不变。本模拟试验采用非静力正二十面体网格模式（ICOsahedral Non-hydrostatic, ICON）开展（Zängl等，2015）。鉴于水平网格间距为2.5千米，无需启用对流参数化方案，对流过程可通过整体微物理方案显式解析；该方案可预报云水、雨水、雪、冰晶以及霰（Graupel）的演变过程（Baldauf等，2011）。重力波拖曳与次网格地形的参数化方案均已关闭，其余配置与德国气象局（German Weather Service, DWD）当前使用的业务模式版本完全一致，详细参数设置可参考Zängl等（2015）与Klocke等（2017）的相关研究。