Fig 6. Variation in reconstructed northwest Australian precipitation, the Southern Annular Mode, The Ningaloo Niño and the El Niño Southern Oscillation over the last two centuries.
(a) Reconstructed precipitation in semi-arid northwest Australia; the Southern Annular Mode (SAM) (b) as an observation-based index calculated by the British Antarctic Survey (BAS) and two instrumental reconstructions by (c) Visbeck [72] and (d) Fogt [70,71] and (e) a tree-ring based reconstruction of the SAM [65]; (f) the Ningaloo Niño index (NNI, see text for definition); and the El Niño Southern Oscillation (ENSO), as (g) the Southern Oscillation Index (SOI) and (h) the Niño 4 SST index. Darker lines in each plot are 20-year loess smoothing curves. “Wet” and “Dry” labels indicate the typical effect of the SAM, NN and ENSO on summer-autumn precipitation in inland northwest Australia. The shaded box highlights the timing of the recent wet period in inland semi-arid northwest Australia.