Spatial-temporal patterns and driving mechanisms of semiannual variations in the Philippine Sea

► We explore semiannual variations in the Philippine Sea with Altimetric SSH data. ► Semiannual changes contribute considerably to the total annual SSH variance. ► The North Equatorial Current bifurcation latitude shows weak semiannual changes. ► Semiannual variations are primarily driven by wind forcing in western Pacific. ► Semiannual changes are also prominent in wind forcing field.