Figure 06

Intraseasonal propagation in the region 70o–100oE, 20oS–30oN using 24–70-day bandpass filtered data, for May to October only, illustrated by lag correlations at each latitude between zonally-averaged data and the OLR time series (also filtered) at a base point 85oE, 12.5oN. Coloured shading is for zonally-averaged OLR. Green lines show propagation from 0o to 12.5oN, and 12.5o to 20oN. Blackcontours are for zonally-averaged SST, with solid (dashed) contours indicating negative (positive) correlation (remembering that negative OLR anomalies correspond to increased convection) and the contour interval being the same as for the coloured shading. SST is shown up to 17.5oN only, where half of the longitude domain is occupied by land. The vertical dotted line shows the latitude of the base point. (a) Observations/reanalysis (AVHRR OLR and ERA-Interim SST), (b) GL90, (c) AO_PO90, (d) ATM90[~GL] (n.b., SST correlations are too small to appear), (e) IO90, (f) ATM90[–GL], (g) ATM90[~IO].