Page History

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• Surface weather stations, ships, and buoys.
  • Surface pressure observations are used over land and sea.
  • Wind speed and direction observations from ships and buoys are used.  
  • Wind observations from land stations or even from islands or coastal stations are not used.  
  • Screen temperatures over land are used in the analysis.  Screen temperatures over land are adjusted to the 2m level by taking account of:
    • the vertical distance between the observations and grid point altitude using a modified interpolation function rather than fixed value of stability.
    • land use and land cover with the associated high and low vegetation values which are taken from a new leaf area index (LAI).   Vegetation varies throughout the year but has most influence in spring and summer.
    • surface albedo for forests with underlying snow based on processed satellite data rather than tabulated values.
  • Screen temperature and dew point observations are actively used over land in a separate analysis of soil moisture.
  • Observed temperatures are not used in the analysis where the difference between observed and background temperature is greater than 7.5°C.
  • Some ocean observations are reported from instrumented marine mammals.
  • Cloud cover is not assimilated.

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