HESS

Hydrology and Earth System Sciences

HESS

Hydrol. Earth Syst. Sci.

1607-7938

Copernicus Publications

Göttingen, Germany

10.5194/hess-7-197-2003

Modelling persistence in annual Australia point rainfall

Whiting

J. P.

¹ Lambert

M. F.

³ ¹ Metcalfe

A. V.

Centre for Applied Modelling in Water Engineering, School of Civil and Environmental Engineering, University of Adelaide, Adelaide 5005, Australia

Department of Applied Mathematics, University of Adelaide, Adelaide 5005, Australia

Email for corresponding author: mlambert@civeng.adelaide.edu.au

30 04 2003

7 2 197 211

2003

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This article is available from https://hess.copernicus.org/articles/7/197/2003/hess-7-197-2003.html

The full text article is available as a PDF file from https://hess.copernicus.org/articles/7/197/2003/hess-7-197-2003.pdf

Annual rainfall time series for Sydney from 1859 to 1999 is analysed. Clear evidence of nonstationarity is presented, but substantial evidence for persistence or hidden states is more elusive. A test of the hypothesis that a hidden state Markov model reduces to a mixture distribution is presented. There is strong evidence of a correlation between the annual rainfall and climate indices. Strong evidence of persistence of one of these indices, the Pacific Decadal Oscillation (PDO), is presented together with a demonstration that this is better modelled by fractional differencing than by a hidden state Markov model. It is shown that conditioning the logarithm of rainfall on PDO, the Southern Oscillation index (SOI), and their interaction provides realistic simulation of rainfall that matches observed statistics. Similar simulation models are presented for Brisbane, Melbourne and Perth. Keywords: Hydrological persistence,hidden state Markov models, fractional differencing, PDO, SOI, Australian rainfall