Seasonal cycle of the total ozone content over Southern high latitudes in the CCM SOCOLv3.

This dataset is the output from simulations conducted using the SOCOLv3 model. We use it to study sensitivity of the TCO over Antarctica to the; (1) efficiency of the stratospheric heterogeneous reactions (SR1), and (2) intensity of the meridional flux into the polar regions due to sub-grid scale mixing processes (SR2) and (3) accuracy of the pho-to-dissociation rate calculations. (SR3). The data includes the following output variables: total ozone, ozone (O3), methane (CH4), nitrous oxide (N2O), hydroxyl (OH), ClOx family, O(1D). The data is stored in NetCDF format. Zip file contains the output for four experiments, described below. 1. Reference run (RR) To compare the CCM SOCOLv3 original calculation results with the IKFS2 measurements we have undertaken a 19-year-long reference numerical experiment for the 2000-2018 period. The first 14 years (2000-2013) of the model calculations were considered as spin up. It is necessary for the adaptation of the chemical composition and dynamics of the model atmosphere to the specific boundary conditions. The last 5 years of the model experiment (2014-2018) were used for analysis and comparison with the correspondent IKFS2 observations. As boundary conditions, we considered the long-term (2000-2018) evolution of the ozone depletion substance (ODS), greenhouse gas concentrations GHG, sea surface temperature and sea ice concentration (SST/SIC), and zonal winds in the equatorial stratosphere (QBO). The mixing ratios of ODS in the lower troposphere evolved according to the World Meteorological Organization (WMO) data (WMO, 2018). The atmospheric mixing ratios of the main GHG (CO2, CH4, and N2O) are taken from (Meinshausen et al., 2017) until 2014 and extended to 2018 following the IPCC SSP2-4.5 scenario (Meinshausen et al., 2020). The SST/SIC fields for the 21st century prescribed as monthly means are adopted from the HadISST1 dataset provided by the UK Met Office Hadley Centre (Rayner et al., 2003). The QBO is produced by a linear relaxation (“nudging”) of the model zonal winds in the equatorial stratosphere to a time series of observed winds (28, Giorgetta et al., 1996). The nudging is used between 20o N and 20o S from 90 hPa up to 3 hPa. Within the QBO core domain (10o N–10o S, 50– 8 hPa) the relaxation time is uniformly set to 7 days; outside this region, the damping depends on latitude and altitude (Giorgetta et al., 2006). Also, the evolutions of the 11-year solar activity (Matthes et al., 2017), stratospheric aerosol contents (Kovilakam et al., 2020), and the surface CO and NOx emissions from CMIP6 input4MIPs databases for the historical period to 2014 and following RCP2-4.5 until 2018 (Hoesly et al., 2018) were applied in the model runs as boundary conditions. 2. Sensitivity runs. The above-mentioned TCO discrepancies between model and satellite data probably can be explained by the poor model representations of the processes that are responsible for the polar ozone state. According to the modern scientific paradigm, the ozone content in the polar stratosphere is controlled mainly by the rates of the heterogeneous reactions and the photodissociation of ozone molecules by solar radiation at the large zenith angles of the Sun (Brasseur and Solomon, 2005). Also, the level of TCO inside the inner part of the SH polar night vortex can depend on the horizontal resolution of the model (Shuhua et al., 2002). So, if the model grid is rather rough it makes sense to consider the transport of the model species into the polar night vortexes by the sub-grid scale motions. Table 1. A short description of the sensitivity runs with CCM SOCOLv3. Name of model run Short description of the model run SR1 Two times reduction of the heterogenies reaction HCl + ClONO2 → Cl2 + HNO3 rate. SR2 Intensification of the horizontal mixing process of all transported model species into the SH polar vortex with diffusion coefficient Kyy = 5·106 m2/s in its maximum. SR3 Using the Cloud-J module installed in the SOCOLv3 model to calculate photolysis rates Therefore, to investigate the causes of the TCO underestimation and find some reasonable refinement of the model accuracy, we performed set of additional numerical runs with CCM SOCOLv3 described in the Table 1. All these model runs were designed exactly as the reference run (boundary conditions, spin-up, using the 2016-2018 years model results for comparison with the satellite data).本数据集为使用SOCOLv3模式开展的模拟实验输出结果，用于研究南极地区总柱臭氧（Total Column Ozone, TCO）对以下三项因素的敏感性：(1) 平流层非均相反应效率（SR1）；(2) 由次网格尺度混合过程（SR2）引发的向极区经向输送强度；以及(3) 光解离速率计算的准确性（SR3）。 数据集包含以下输出变量：总柱臭氧、臭氧（O₃）、甲烷（CH₄）、一氧化二氮（N₂O）、羟基自由基（OH）、氯氧化物（ClOx）家族以及O(¹D)。数据以NetCDF格式存储，压缩包包含四项实验的输出结果，详情如下。 1. 参考实验（Reference Run, RR） 为将耦合化学气候模式（Coupled Chemistry-Climate Model, CCM）SOCOLv3的原始计算结果与IKFS2观测数据进行对比，我们针对2000-2018年开展了一项为期19年的参考数值实验。其中模式计算的前14年（2000-2013年）被视为自旋启动阶段，用于使模式大气的化学组成与动力场适配特定边界条件；最后5年（2014-2018年）的模式结果则用于分析，并与对应的IKFS2观测数据进行对比。 本次实验采用的边界条件包括：2000-2018年臭氧消耗物质（Ozone Depleting Substances, ODS）、温室气体（Greenhouse Gas, GHG）浓度的长期演变，海表温度与海冰浓度（Sea Surface Temperature and Sea Ice Concentration, SST/SIC），以及赤道平流层准两年振荡（Quasi-Biennial Oscillation, QBO）。对流层低层的ODS混合比依据世界气象组织（World Meteorological Organization, WMO）2018年发布的数据设定。主要温室气体（CO₂、CH₄、N₂O）的大气混合比在2014年前取自Meinshausen等人2017年的研究成果，2014年后则依据政府间气候变化专门委员会（Intergovernmental Panel on Climate Change, IPCC）SSP2-4.5情景（Meinshausen et al., 2020）外推至2018年。 21世纪的SST/SIC月平均场取自英国气象局哈德利中心（UK Met Office Hadley Centre）发布的HadISST1数据集（Rayner et al., 2003）。QBO通过将模式赤道平流层的纬向风向观测风时间序列进行线性松弛（nudging，即张弛同化）得到（Giorgetta et al., 1996），松弛作用范围为南北纬20°之间、气压90 hPa至3 hPa的区域。在QBO核心区域（南北纬10°之间、50-8 hPa），松弛时间统一设为7天；在此区域外，阻尼强度随纬度与高度变化（Giorgetta et al., 2006）。此外，模式运行中还加入了11年太阳活动周期演变（Matthes et al., 2017）、平流层气溶胶含量（Kovilakam et al., 2020），以及历史时期至2014年取自CMIP6 input4MIPs数据库、2014年后依据RCP2-4.5情景的地表CO与NOₓ排放数据（Hoesly et al., 2018）作为边界条件。 2. 敏感性实验 模式结果与卫星观测数据之间的TCO偏差，可能源于模式对极地臭氧状态相关物理化学过程的表征不足。根据当前主流科学认知，极地平流层臭氧含量主要受控于非均相反应速率以及大太阳天顶角下太阳辐射对臭氧分子的光解离过程（Brasseur and Solomon, 2005）。此外，南半球极夜涡旋内部区域的TCO水平还可能依赖于模式的水平分辨率（Shuhua et al., 2002）。因此，若模式网格较为粗糙，则有必要考虑次网格尺度运动对模式示踪物向极夜涡旋的输送过程。 表1 基于CCM SOCOLv3的敏感性实验简要说明 | 模式实验名称 | 实验简要说明 | | ---- | ---- | | SR1 | 将非均相反应HCl + ClONO₂ → Cl₂ + HNO₃的反应速率降低至原水平的1/2 | | SR2 | 强化所有输送型模式示踪物向南半球极涡的水平混合过程，其扩散系数Kyy的最大值设定为5×10⁶ m²/s | | SR3 | 采用SOCOLv3模式内置的Cloud-J模块计算光解速率 | 为探究TCO被低估的成因并优化模式计算精度，我们基于表1所列方案开展了一系列补充数值实验。所有敏感性实验的设置均与参考实验保持一致，包括边界条件设定、自旋启动阶段，以及采用2016-2018年的模式结果与卫星观测数据进行对比。