Section 9.11 Comparing IFS and AIFS output

A few tentative observations can be made regarding AIFS and IFS and differences in output:

• AIFS-Single, AIFS Control (and AIFS-ENS) have distinctly different training methods.
  • AIFS-Single has RMSE training strategy, stochastic physics (SPP) not active.
  • AIFS-Control (and AIFS-ENS) has regression training strategy, SPP not active. AIFS-Control also has perturbations, somewhat analogous to SPP).
• IFS Control (and IFS ENS) uses SPP.

Generally, using same initial conditions:

• AIFS-Single is similar to IFS-Control but has a smoother look.
• AIFS-ENS sample member x and IFS-ENS sample member x are very different (possibly result of no SPP in AIFS).
• AIFS-Control similar to a sample AIFS-ENS member (more similar at short leads as expected).
• AIFS-Control similar to a sample IFS ENS member but has more noteworthy peaks (resolution differences).
• IFS-ENS sample member x has much larger peaks of values than IFS-Control sample member x (strong impact of SPP).