"" . "sea_surface_swell_wave_mean_period"@en . "SDN:P07::8WMKETJA" . "SDN:P07::8WMKETJA" . "1" . . . . "SDN:P07::8WMKETJA" . "2017-03-27 15:08:34.0" . "2017-03-27 15:08:34.0" . . "A period is an interval of time, or the time-period of an oscillation. Wave period is the interval of time between repeated features on the waveform such as crests, troughs or upward passes through the mean level. Wave mean period is the mean period measured over the observation duration. Swell waves are waves on the ocean surface and are the low frequency portion of a bimodal wave frequency spectrum."@en . "1" . . . "false" . "accepted"@en . .