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. Black contours
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].
Funding
National Environment Research Council (NERC) NE/L013800/1 and NE/L010976/1