Subtropical Australia is a region with a short and sparsely documented hydroclimate history. Existing evidence suggests this region presents a pattern of hydroclimate variability that is inconsistent with the rest of eastern Australia. The strong nature of extreme events in this region as evidenced by devastating floods and droughts is also noted. The long-term hydroclimate variability of this region needs to be better understood so that adaptation and management practices can be developed to reduce the impact of extreme events. To extend the instrumental records dendroclimatology can be used as there are several remnant forest stands with multi-century aged trees across the subtropics that may be useful in developing long-term annual hydroclimate reconstructions.

Here we look at 140 instrumental rainfall stations across Southeast Queensland (SEQ) to identify trends in both temporal and spatial variability from 1908-2007. Pearson correlation analysis between each station has correlated the stations into proximal groups. For each group annual deviations from the mean are developed and analysis of above and below average rainfall phases has been undertaken. This assessment shows rainfall is not uniform across SEQ and can in fact be categorised into several spatial patterns of temporal variability. Additional assessment of all instrumental streamflow gauges of longer than 50 years duration suggests these spatial patterns also apply to the streamflow networks. Connections of SEQ hydroclimate to the El Niño Southern Oscillation and the Interdecadal Pacific Oscillation are also found in the record.

Currently only three single site tree-ring hydroclimate reconstructions exist in SEQ which when compared to the hydroclimate groups suggest single site records are representative of the spatial groups they are contained within and that alone they cannot represent large spatial areas. The implications this has on long-term hydroclimate understanding for this and other similar regions of high economic value are discussed.