Global Ocean Heat Content Anomalies based on Argo data

NOTE for users: please use the latest version of the product at https://zenodo.org/doi/10.5281/zenodo.10182972. Ocean Heat Content Anomalies (OHCA) are calculated (during 2005-2022) subtracting the mean over the period 2005-2021 from the monthly time series. Yearly OHCA time series are then calculated. OHC fields are mapped using locally stationary Gaussian processes with data-driven decorrelation scales (Kuusela and Stein, 2018). A linear time trend was included in the estimate of the mean field (along with spatial terms and harmonics for the annual cycle). In the present version, mapping is done in latitude and longitude with monthly subsets of data (a future version will add time to the mapping). Mapping is done separately for different vertical sections. Different vertical sections are combined to estimate: 1. Global OHC timeseries (e.g., for level 0-2000m: GCOS_0000_2000_OHCA_J_m2_oc, for OHC in J/m2; GCOS_0000_2000_OHCA_ZJ, for OHC in ZJ; the attribute “GCOS_area” is included for both variable types in the netcdf file and it tells the corresponding surface area); 2. Volume averaged temperature anomaly (global) timeseries (e.g., for level 0-2000m: GCOS_0000_2000_vol_ave_temp_anom, in degC; the attribute “GCOS_volume'' is included for this variable type in the netcdf file and it tells the corresponding volume). Regions of the ocean that are shallower than 300 m or are not sufficiently well sampled by the Argo array are not included.

用户须知：请访问https://zenodo.org/doi/10.5281/zenodo.10182972获取该产品的最新版本。
海洋热含量距平（Ocean Heat Content Anomalies, OHCA）的计算方式为：将2005-2022年的逐月时间序列减去2005-2021年的气候态平均值，随后据此生成逐年的海洋热含量距平时间序列。
海洋热含量（Ocean Heat Content, OHC）场的空间映射采用带有数据驱动去相关尺度的局地平稳高斯过程（方法源自Kuusela与Stein, 2018）。在平均场的估算模型中，纳入了线性时间趋势项，同时包含空间项与年循环的谐波分量。
本版本的空间映射基于经纬度网格，采用逐月数据子集完成（未来版本将在映射流程中加入时间维度）。映射操作针对不同垂直断面分别进行，随后整合各断面的结果以估算两类数据集：
1. 全球海洋热含量时间序列：例如针对0-2000米深度层的变量：GCOS_0000_2000_OHCA_J_m2_oc（单位为焦耳每平方米的海洋热含量）、GCOS_0000_2000_OHCA_ZJ（单位为泽焦耳的海洋热含量）；NetCDF（网络通用数据格式）文件中两类变量均附带属性"GCOS_area"，用于标识对应海域的表面积。
2. 全球体积平均温度距平时间序列：例如针对0-2000米深度层的变量：GCOS_0000_2000_vol_ave_temp_anom（单位为摄氏度）；该变量类型附带属性"GCOS_volume"，用于标识对应海域的总体积。
深度不足300米或阿尔戈（Argo）观测阵列采样不充分的海域，未被纳入本数据集。