Data for 'Local verses farfield control on South Pacific mode water variability'

The adjoint files contained in two .zip folders here are the output files of two adjoint sensitivity experiments in the South Pacific mode water formation regions, CENTRAL and EASTERN, using ECCOv4r4. The first set of outputs is for the sensitivity of the volume in the Central mode water pool to net heat flux. The folder CENTRAL.zip contains these files which are of the form ADJqnet_CENTRAL.XX.data/.meta, where XX is the timestep. The second set of outputs is for the sensitivity of the volume in the Eastern mode water pool to net heat flux. The folder EASTERN.zip contains these files which are of the form ADJqnet_EASTERN.XX.data/.meta, where XX is the timestep. Both sets of data contained here are the output/sensitivity files for 6 years at 14 day time steps. The forward perturbation files contained in four .zip folders here are the output files of four separate forward perturbation experiments, using ECCOv4r4. The first set of outputs is for a forward perturbation experiment related to the Central mode water pool sensitivities, where the perturbation is set in an area of negative sensitivity and uses a negative perturbation in the folder C_ns_np.zip. The folder C_ns_np.zip contains these files which are of the form THETA_mon_mean.XX.data/.meta, SALT_mon_mean.XX.data/.meta, and MXLDEPTH_mon_mean.XX.data/.meta, where XX is the times. The second set of outputs is for a forward perturbation experiment related to the Central mode water pool sensitivities, where the perturbation is set in an area of negative sensitivity and uses a positive perturbation in the folder C_ns_pp.zip. The folder C_ns_pp.zip contains these files which are of the form THETA_mon_mean.XX.data/.meta, SALT_mon_mean.XX.data/.meta, and MXLDEPTH_mon_mean.XX.data/.meta, where XX is the times. The third set of outputs is for a forward perturbation experiment related to the Central mode water pool sensitivities, where the perturbation is set in an area of positive sensitivity and uses a negative perturbation in the folder C_ps_np.zip. The folder C_ps_np.zip contains these files which are of the form THETA_mon_mean.XX.data/.meta, SALT_mon_mean.XX.data/.meta, and MXLDEPTH_mon_mean.XX.data/.meta, where XX is the times. The fourth set of outputs is for a forward perturbation experiment related to the Central mode water pool sensitivities, where the perturbation is set in an area of positive sensitivity and uses a positive perturbation in the folder C_ps_pp.zip. The folder C_ps_pp.zip contains these files which are of the form THETA_mon_mean.XX.data/.meta, SALT_mon_mean.XX.data/.meta, and MXLDEPTH_mon_mean.XX.data/.meta, where XX is the times. All sets of data contained here are the output/forward perturbation files for 3 years at 14 day time steps, starting when the perturbation begins. The THETA and SALT files from the forward perturbation experiments are used to create neutral density files using the gibbs seawater toolbox in MATLAB. These perturbed neutral densities are then used to find the difference the perturbation makes in relation to a control experiment. Paper abstract: In the South Pacific mode water formation region, central and eastern pools of mode water have been found to be linked to winter mixed-layer thicknesses that vary strongly interannually and out of phase across the basin. This mixed-layer variability is associated with peaks in sea level pressure variability at a quasi-stationary anomaly situated between the two pools. To investigate how surface forcing, as well as the propagation of upstream anomalies, affects the formation of these mode water pools, a set of adjoint sensitivity experiments with a density-following feature are conducted. Adjoint sensitivities reveal local cooling can lead to an increase in mode water pool volume through mixed-layer depth changes and lateral density surface movement. In addition, upstream warming along the Antarctic Circumpolar Current can lead to an increase in mode water pool volume through lateral density surface movement. Optimal conditions for mode water formation involve a combination of local cooling and upstream warming of mode water formation sites. Hence, South Pacific mode water variability is particularly sensitive to atmospheric modes which lead to a dipole in heating across the formation sites.本数据集包含两个.zip压缩文件夹，其内存储的伴随文件为基于ECCOv4r4模式，在南太平洋模态水（mode water）形成区（中部与东部子区域）开展的两次伴随敏感性实验（adjoint sensitivity experiment）的输出结果。第一组输出结果对应中部模态水团体积对净热通量（net heat flux）的敏感性。CENTRAL.zip文件夹内包含此类文件，文件名格式为ADJqnet_CENTRAL.XX.data/.meta，其中XX为时间步序号。第二组输出结果对应东部模态水团体积对净热通量的敏感性。EASTERN.zip文件夹内包含此类文件，文件名格式为ADJqnet_EASTERN.XX.data/.meta，其中XX为时间步序号。本部分两组数据均为以14天为时间步长、时长6年的输出/敏感性文件。 本数据集另含四个.zip压缩文件夹，其内存储的正向扰动文件为基于ECCOv4r4模式开展的四次独立正向扰动实验的输出结果。第一组输出结果对应与中部模态水团敏感性相关的正向扰动实验：扰动设置在敏感性为负的区域，且采用负向扰动，相关文件存储于C_ns_np.zip文件夹中。该文件夹内的文件格式为THETA（位温）月均.XX.data/.meta、SALT（盐度）月均.XX.data/.meta以及MXLDEPTH（混合层深度）月均.XX.data/.meta，其中XX为时间步序号。第二组输出结果对应与中部模态水团敏感性相关的正向扰动实验：扰动设置在敏感性为负的区域，且采用正向扰动，相关文件存储于C_ns_pp.zip文件夹中。该文件夹内的文件格式为THETA_mon_mean.XX.data/.meta、SALT_mon_mean.XX.data/.meta以及MXLDEPTH_mon_mean.XX.data/.meta，其中XX为时间步序号。第三组输出结果对应与中部模态水团敏感性相关的正向扰动实验：扰动设置在敏感性为正的区域，且采用负向扰动，相关文件存储于C_ps_np.zip文件夹中。该文件夹内的文件格式为THETA_mon_mean.XX.data/.meta、SALT_mon_mean.XX.data/.meta以及MXLDEPTH_mon_mean.XX.data/.meta，其中XX为时间步序号。第四组输出结果对应与中部模态水团敏感性相关的正向扰动实验：扰动设置在敏感性为正的区域，且采用正向扰动，相关文件存储于C_ps_pp.zip文件夹中。该文件夹内的文件格式为THETA_mon_mean.XX.data/.meta、SALT_mon_mean.XX.data/.meta以及MXLDEPTH_mon_mean.XX.data/.meta，其中XX为时间步序号。本部分所有数据集均为以14天为时间步长、时长3年的正向扰动输出文件，起始时刻为扰动施加时刻。 本正向扰动实验产出的THETA与SALT文件，将通过MATLAB的Gibbs海水工具箱（Gibbs Seawater Toolbox）用于生成中性密度（neutral density）文件。后续将基于这些经扰动的中性密度文件，计算扰动实验与对照实验间的差值。 论文摘要：在南太平洋模态水形成区，中部与东部模态水团被发现与冬季混合层厚度密切相关——该厚度存在显著的年际变化，且在整个海盆范围内呈现反相位特征。此类混合层变率与两个水团之间准静止异常处的海平面气压（sea level pressure）变率峰值相关联。为探究表面强迫以及上游异常传播如何影响上述模态水团的形成，研究团队开展了一组具备密度追踪特性的伴随敏感性实验。伴随敏感性分析结果表明，局地冷却可通过改变混合层深度与密度面的横向移动，使模态水团体积增加。此外，沿南极绕极流（Antarctic Circumpolar Current）的上游增暖，可通过密度面的横向移动使模态水团体积增加。模态水形成的最优条件为：模态水形成区域同时存在局地冷却与上游增暖。因此，南太平洋模态水的变率对能够在形成区域造成加热偶极子分布的大气模态尤为敏感。