GCM Predictability
The GCM (General circulation model) approach for this problem is to take the precipitation, temperature from the GCM which is at a resolution of 2.5 degree. These outputs are then fed into regional climate model which encompasses the feature of the regional topography and other features to produce local precipitation temp at a finer resolution. That is we perform here spatial disaggregation. The outputs from regional climate model can be then given as input into a hydrologic model to get the seasonal streamflow volume and flood peaks.
In the month-month predictability the Echam 4.5 forecasted persisted sea surface temperatures are taken for the particular month and used to predict the flows.Like wise in 3 months predictability the forecasted persisted ssts are taken for the 3 months and averaged to get the predictability of that particular season.