Ocean mask and atmospheric tide derived from ERA5

Data set 1: This data set is a ocean mask file in terms of spherical harmonic coefficients up to degree/order (d/o) 360. Such a ocean mask is used for Inverted Barometer (IB) correction, as shown in the main text. This ocean mask can be transformed into any grid by a harmonic synthesis, which is set to 1 over the ocean and 0 over the continents. Usage of this ocean mask refers to the standard format of gravity fields coefficients. In detail, the leading two columns in the file denote the degree and order respectively. The third and fourth column denote the coefficient 'C' and 'S', respectively.<br>Data set 2: This data set is our tide constitute S1 (diurnal solar tide) derived from ERA5 over 2007-2014. This data set is provided as a ASCII file with a text header and a main body. The header records the basic information of authors and ends with "END OF HEADER". The main body comprises two sub-dataset, of which one is the 'cos' part and another one is the 'sin' part up to degree/order 180. As for the 'cos' part, the leading two columns in the file denote the degree and order respectively, and the third and fourth column denote the coefficient 'cnmCos' and 'snmCos', respectively. As for the 'sin' part, the third and fourth column denote the coefficient 'cnmSin' and 'snmSin', respectively. With all these coefficients ready, the tide S1 at a specific time can be easily reconstructed. <br>Data set 3: This data set is our tide constitute S2 (semi-diurnal solar tide) derived from ERA5 over 2007-2014. Usage of this data set (file) is the same as Data set 2.<br>The rest tide files are directly named after its tide consitute and their usage is the same as Data set 2 as well:ATM_K1.asc, ATM_L2.asc, ATM_M2.asc, ATM_N2.asc, ATM_P1.asc, ATM_R2.asc, ATM_R3.asc, ATM_S3.asc, ATM_T2.asc, ATM_T3.asc.数据集1：本数据集为阶数/次（d/o）最高至360的球谐系数海洋掩膜文件。如正文所述，此类海洋掩膜用于倒气压（Inverted Barometer, IB）校正。该海洋掩膜可通过谐波合成转换为任意网格格式，其海洋区域取值为1，陆地区域取值为0。本海洋掩膜的使用需遵循重力场系数的标准格式。具体而言，文件前两列分别代表阶数与次，第三、第四列则分别对应系数C与S。 数据集2：本数据集为我们基于ERA5数据在2007-2014年间提取的潮汐组分S1（周日太阳潮）。本数据集以ASCII文件形式提供，包含文本表头与主体两部分。表头记录了作者相关基础信息，并以"END OF HEADER"作为结束标识。主体包含两个子数据集，分别为阶数/次最高至180的余弦（cos）部分与正弦（sin）部分。其中余弦部分的前两列分别代表阶数与次，第三、第四列分别对应系数cnmCos与snmCos；正弦部分的第三、第四列则分别对应系数cnmSin与snmSin。获取全部上述系数后，即可轻松重构特定时刻的S1潮汐信号。 数据集3：本数据集为我们基于ERA5数据在2007-2014年间提取的潮汐组分S2（半日太阳潮），其使用方式与数据集2完全一致。 其余潮汐文件均直接以其对应的潮汐组分命名，使用方式同样与数据集2一致，包括：ATM_K1.asc、ATM_L2.asc、ATM_M2.asc、ATM_N2.asc、ATM_P1.asc、ATM_R2.asc、ATM_R3.asc、ATM_S3.asc、ATM_T2.asc、ATM_T3.asc。