source_file trajectory ctd41cp_timestamp latitude longitude profile_id profile_lat profile_lon profile_time sci_m_present_time time conductivity density depth m_pitch m_roll optode_water_temperature oxygen_concentration oxygen_saturation potential_temperature pressure salinity sci_oxy3835_wphase_dphase sci_water_pressure sound_speed temperature u v water_depth crs instrument_ctd instrument_optode platform