1. Short note on seasonal forecasts
John McGregor
Centre for Australian Weather and Climate Research
CSIRO/BOM, Melbourne
27 May 2009

2. Types of monthly SST files – ‘sstfile’
A) monthly-average (bias-corrected or derived from IRI, APCC, etc) SSTs
Typically on C km grid
TXT file with header showing grid, year, month
Interpolated to CC grid from lat/long (or Gaussian grid) data, using amipdata.f or similar
Either simple monthly-average (or boosted version to allow linear interpolation between middle of month – with namip=2)
‘sstfile’ needs to include at least 3 months, in particular month before and after modelled month.
B) monthly climatology file
Usually on C km grid, as above
TXT file as above with header showing grid, year=0, month
Can be produced from type (A) file using amipavg.f

3. Model configuration and switches
Run 1 month at a time
Subsequent months start from the restart file
Supply ‘sstfile’ and corresponding ‘icefile’
For ‘boosted’ SST file, set namip = 2 (e.g. using AMIP SSTs from 1979 onwards). Model uses linear interpolation to get daily values
For simple-average SST file, set namip =3 or 4 – model uses quadratic formula to get daily values each day (namip = 3 just uses simple time interpolation for ice)
To use “persisted anomalies”, supply type (B) average file, and set namip = -1. Same temperature anomaly will be carried through subsequent months. Sea-ice fields will stay at values of beginning of first month (‘icefile’ not needed). Available from version 906