The project helped build the scientific capacity of young scientists in the participating countries on seasonal climate forecasting (SCF). Aside from that, the exercises conducted during the two project workshops provided the opportunity to assess the influence of ENSO based predictive systems on rainfall variability and potential for forecasting in the region. The project also allowed the opportunity to engage with public and policy makers through meetings and public seminars. From discussions with senior government officials it was apparent that consideration of climate information in planning and decision making is growing in SE-Asia. Discussion with senior water managers and agricultural practitioners highlighted the importance of seasonal climate forecasts for water allocation, and risk management decisions. Considerable work, however, needs to be done to transfer the findings of this project into practical risk management decisions. This can best be achieved through developing pilot projects in regions where the potential for forecasting is strong and climate variability can significantly improve resource use and other operational efficiencies. An example is the management of Angat Dam in the Philippines which is the main source of water supply for Metro Manila, but is also used for flood mitigation, hydropower production and agricultural use.
The following are the key findings from the project: impact of ENSO was strong in the Philippines with moderate to high forecasting skill through most of the year with lead times of up to 3 months. Niño 3.4 and SOI had the strongest relationship with rainfall variability across the whole region. Forecasting skill was poor during the peak rainy season (June–August); onset and duration of monsoon in the Philippines and Indonesia was influenced by ENSO with later onset and shorter duration of monsoon during El Niño years and earlier onset and longer duration during La Niña years. On average, the onset of monsoon was up to 38 days later and up to 35 days shorter in El Niño years compared to La Niña years; impact of ENSO on Indonesian rainfall is also strong with moderate to high forecasting skill from June to December, particularly in eastern Indonesia; there appears to be little influence of ENSO on the climate of Bangladesh in terms of the predictability of rainfall, onset and duration of the monsoon season.