Tidetech environmental data — parameters and units

Weather

Short term response of the atmosphere to solar heating and Earth rotation

• Winds at 10m above the sea surface
  • windspeed – ms^-1 or knots
  • wind direction – degrees relative to true North (direction from)
  • east wind – ms^-1 wind towards East
  • north wind – ms^-1 wind towards North
  • gust – ms^-1, maximum instantaneous wind speed in a period
• Atmospheric pressure – Pa (hPa = mbar), air pressure at mean sea level
• Air temperature – degrees Celcius (C) at 2m above the surface (or degrees Kelvin (K) … C = K – 273.15)
• Relative humidity – % at 2m above the surface, a measure of the amount of water vapour in the air
• Cloud cover – fraction between 0 (no cloud) and 1 (total cloud cover)
• Visibility – m, distance view at the surface
• Precipitation – mm/day, accumulated rainfall

Currents

• Tides – generated by the gravitational attraction between the Earth, the Moon and Sun
  • tidal current speed – ms^-1 or knots
  • tidal current direction – degrees relative to true North (direction to)
• Ocean currents – response to atmospheric forcing and differences between water masses in polar and equatorial regions
  • current speed – ms^-1
  • current direction – degrees relative to true North (direction to)
• Coastal currents – response to atmospheric forcing, river inflows and topographic steering
  • current speed – ms^-1
  • current direction – degrees relative to true North (direction to)
• Stokes drift – currents associated with surface wave propagation
  • current speed – ms^-1
  • current direction – degrees relative to true North (direction to)

Surface waves 

Generated by the action of winds on the sea surface

• Significant wave height – m, the mean of one third of the highest waves in a given period
• Peak wave period – seconds, the period of the wave spectral peak
• Peak wave direction – degrees relative to true North (direction from) of the wave spectral peak
• Wind wave height – m, the mean wave height driven by local winds in a given period
• Wind wave period – seconds, the period of the mean wind wave periods
• Wind wave direction – degrees relative to true North (direction from) of the mean wind wave
• Swell wave height – m, the mean swell wave height of the major (primary) swell component in a given period
• Swell wave period – seconds, the period of the mean swell wave periods
• Swell wave direction – degrees relative to true North (direction from) of the mean swell waves

Oceanographic

Other parameters

• Sea ice thickness – m, vertical extent of ice floating in the sea which has formed from freezing sea water
• Sea Surface Temperature – degrees Celcius (C), the foundation temperature of the sea surface layer
• Sea Surface Salinity – salinity units (psu), saltiness of the sea water at the sea surface
• Sea surface height – m, ocean sea surface height above the geoid
• Tidal elevation – m, tidal sea surface height above mean sea level
• Chlorophyll_a – mgm^-3, values of mass concentration of chlorophyll_a, an indication of primary production
• Sea ice fraction – fraction between no ice (=0) and total ice coverage (=1); all ice floating in the sea which has formed from freezing sea water