Possible ENSO signals prior to the Last Glacial Maximum, during the last deglaciation and the early Holocene, from New Zealand

Abstract

Annually laminated lake sediments from a maar crater in Auckland, New Zealand, were analyzed spectrally for three time slices: just prior to the last glacial maximum (LGM), during the deglaciation and during the early Holocene. Strong spectral power in 2-7 year, 9-30 year and a centennial (80-120 year) timescale prior to the LGM and during two brief intervals in the deglaciation contrasts with virtually no spectral power during the rest of the deglaciation and during the early Holocene. The Antarctic Cold Reversal (ACR) appears to be the younger deglacial event. The results indicate that El Niño Southern Oscillation (ENSO) and possibly the Inter-decadal Pacific Oscillation (IPO), operated in a modern mode prior to the LGM, pulsed on and off during the deglaciation and were suppressed or absent from northern New Zealand during the early Holocene. The ACR was a period of enhanced south-westerly flow over northern New Zealand. Copyright 2004 by the American Geophysical Union.