Coupled land-ocean-atmosphere processes and South Asian monsoon variability

Results from a global coupled ocean-atmosphere climate model and a model with specified tropical convective heating anomalies show that the South Asian monsoon was an active part of the tropical biennial oscillation (TBO). Convective heating anomalies over Africa and the western Pacific Ocean associated with the TBO altered the simulated pattern of atmospheric circulation for the Northern Hemisphere winter mid-latitude over Asia. This alteration in the mid-latitude circulation maintained temperature anomalies over South Asia through winter and helped set up the land-sea temperature contrast for subsequent monsoon development. South Asian snow cover contributed to monsoon strength but was symptomatic of the larger scale alteration in the mid-latitude atmospheric circulation pattern.