Versions Compared

Old Version 5

changes.mady.by.user Bob Owens

Saved on

compared with

New Version 6

changes.mady.by.user Bob Owens

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

  • The area of coverage includes high latitudes but every pixel is assumed to be an overhead (nadir) view.
  • The solar illumination is always assumed to be directly overhead.  This means that cloud structures can still be seen at times and locations even when in reality it is dark.
  • Unlike on real visible images, shadowing from clouds is never represented.
  • The displayed cloud reflectance is a function of the total column cloud liquid water.  When this is modelled too low the low clouds do not stand out well.  The because reflectance depends on optical depth.  This can cause uncertainty as:
    • sometimes low cloud does not show up well. The reflectance can be close to the reflectance from the surface and then clouds can’t be distinguished from terrain.
    • the amount of cloud condensate along the optical path is incorrect in the model, and/or because the optical path in the simulated image is not the same as the optical path in reality.

Users should check model cloud fields to get a complete picture.

Simulated infra-red imagery

...