Antarctic Circumpolar Wave

The Antarctic Circumpolar Wave is a coupled ocean/atmosphere wave that circles the Southern Ocean in approximately eight years. Since it is a wave-2 phenomenon (there are two ridges and two troughs in a latitude circle) at each fixed point in space a signal with a period of four years is seen. The wave moves eastward with the prevailing currents.

Note that although the "wave" is seen in temperature, atmospheric pressure, sea ice and ocean height, the variations are hard to see in the raw data and need to be filtered to become apparent. Because the reliable record for the Southern Ocean is short (since the early 1980s) and signal processing is needed to reveal its existence, some climatologists doubt the existence of the wave. Others accept its existence but say that it varies in strength over decades.

The wave was discovered simultaneously in 1996 by Warren White and R G Peterson; and by Jacobs and Mitchell. Since then, ideas about the wave structure and maintenance mechanisms have changed and grown: by some accounts it is now to be considered as part of a global ENSO wave.

See also

• Antarctic Circle
• Antarctic Convergence

References

• White, W.B. and R.G. Peterson (1996), An Antarctic circumpolar wave in surface pressure, temperature and sea-ice extent. Nature 380:699–702
• Jacobs, G. A., and J. L. Mitchell (1996), Ocean circulation variations associated with the Antarctic Circumpolar Wave. Geophysical Research Letters 23(21):2947–50
• Connolley, W. M. (2002), Long-term variation of the Antarctic Circumpolar Wave, Journal of Geophysical Research. doi:10.1029/2000JC000380

External links

• Antarctic Circumpolar Wave Description
• The Antarctic Circumpolar Wave: A Beta Effect in Ocean–Atmosphere Coupling over the Southern Ocean