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.