资源环境科技发展态势分析平台

The temporal and spatial structure of El Nino-Southern Oscillation (ENSO)-modulated convection is analysed. Computation of the leading empirical orthogonal function mode in filtered satellite outgoing longwave radiation (OLR) fields yields a time score with a 4-5 year cycle that follows Nino3.4 sea surface temperature (SST), and a spatial loading pattern with global wave-2 structure. Alternating centres of action are located over the central Pacific, West Atlantic, west Indian and Maritime Continent. The wave-2 pattern is underpinned by a split Walker cell and June-August SST anomalies in the equatorial Atlantic opposite to the East Pacific and west Indian Oceans. Hovmoller plots of the upper velocity potential and sea surface height exhibit continuous eastwards propagation of a wave-1 pattern in the 2010-2016 ENSO cycle. Atmospheric convection (OLR) reflects basin-scale patterns that switch sign with ENSO phase, as coupled zonal propagating waves become super-positioned.