Australia: The Land Where Time Began

A biography of the Australian continent 

Ningaloo Niño – Decadal Increase Since the Late 1990s

Ningaloo Niño is the episodic occurrence of ocean conditions that are anomalously warm along the subtropical coast of Western Australia (WA). Typically the Ningaloo Niño develops in the southern spring, peaking in summer, and then decaying in autumn, often occurring in conjunction with the La Niña conditions in the Pacific Ocean during which the transport of warm tropical waters towards the pole by the Leeuwin Current is promoted. Feng et al. say there has been a marked increase in the occurrence of Ningaloo Niño since the late 1990s, and suggest this is likely to be related to the negative phase of the Interdecadal Pacific Oscillation (IPO) and enhanced El Niño-Southern Oscillation (ENSO) variance since the 1970s. Positive heat content anomalies are sustained by the swing to the negative IPO, which also initiates more frequent cyclonic wind anomalies off the coast of Western Australia, which favours an enhancement of heat flow towards the pole by the Leeuwin Current. Feng et al. suggest the anthropogenically forced global warming has made it easier for extreme ocean temperatures in the region to be driven by natural variability.

Sources & Further reading

1. Feng, M., H. H. Hendon, S.-P. Xie, A. G. Marshall, A. Schiller, Y. Kosaka, N. Caputi and A. Pearce (2015). "Decadal increase in Ningaloo Niño since the late 1990s." Geophysical Research Letters 42(1): 2014GL062509.