Assessment of the impacts of the 1997–98 El Niño on the Asian‐Australia Monsoon

Singular Value Decomposition (SVD) analyses of rainfall and sea surface temperature (SST) are carried out globally over the entire tropics and regionally over the Asia‐Australian (AA)‐monsoon domain. Contributions to monsoon rainfall predictability by basin‐scale SST forcing and regional SST coupling are evaluated from cumulative anomaly correlation with dominant regional SVD modes. The observed 1997–98 AA‐monsoon anomalies are found to be very complex with approximately 34% of the anomalies of the Asian (boreal) summer monsoon and 74% of the Australia (austral) monsoon attributable to basin‐scale SST influence associated with El Niño. For the boreal and austral monsoon respectively, regional coupled processes contribute an additional 19% and 10%, leaving about 47% and 16% due to other factors including high frequency transients. Results suggest that in order to improve seasonal‐to‐interannual predictability of the AA‐monsoon, we need to investigate and exploit not only monsoon‐El Niño relationship, but also intrinsic monsoon regional coupled processes.