P-01 P-02 P-03 P-04 P-05 P-06 P-07 P-08 P-09 P-10 P-11 P-12 P-13 P-14 P-15 P-16 P-17 DA-Menu Ross-home

PREVIOUS NEXT


Correction phase A in 4d Var. ('gradient')


  • Gradients of the observation part of the cost function with respect to pressure and potential temperature fields (model level 22 shown) are advected backwards in time (12 timesteps).
  • The observation that we are interested in occurs at t=7.
  • The gradient fields at t=0 show which regions of the atmosphere influence the model observation. There is thus information in the ATOVS observation to allow these regions to be modified (there are a few other observations also present in this 4d Var. run).


d(Jobs)/d(Pressure) (left) d(Jobs)/d(Potential temperature) (right)