- Title
- Modelling daily rainfall along the east coast of Australia using a compound distribution Markov Chain model
- Creator
- Chowdhury, A. F. M. Kamal; Lockart, Natalie; Willgoose, Garry; Kuczera, George; Kiem, Anthony S.; Parana Manage, Nadeeka
- Relation
- 36th Hydrology and Water Resources Symposium: The Art and Science of Water (HWRS2015). Proceedings of the 36th Hydrology and Water Resources Symposium (Hobart, Tas. 7-10 December, 2015) p. 625-632
- Publisher
- Engineers Australia
- Resource Type
- conference paper
- Date
- 2015
- Description
- A widely known issue in daily rainfall simulation is that daily simulation models often underestimate the long term variability of observed rainfall, which can lead to an overestimation of reservoir reliability in urban water planning. We have developed a Compound Distribution Markov Chain (CDMC) model to stochastically generate daily rainfall time series. The CDMC model uses time-invariant parameters of the two-state Markov Chain process (transition probabilities of wet-to-wet and dry-to-dry days) for modelling the rainfall occurrence. The rainfall depth on the wet days is modelled using a gamma distribution. The gamma parameters are sampled from a bivariate normal distribution of log normally distributed mean and standard deviation of wet day rainfall over the sampling period. In this study, we calibrated the CDMC model to data from the Hunter River Catchment in the east coast of NSW, Australia, known to have prominent East Coast Low (ECL) impacts. To calibrate the model parameters, we used dynamically downscaled high resolution gridded data produced by NSW/ACT Regional Climate Modelling project for the reanalysis period of 1950-2009. In addition, high resolution gridded ground based data from the Australian Water Availability Project was used. Our results show that the CDMC model satisfactorily preserves the mean and standard deviation of observed rainfall in both short (daily) and longer (monthly to multi-year) timescales. The findings of this study will be the basis for future work examining the influence of ECLs in urban water security of coastal NSW.
- Subject
- daily rainfall simulation; observed rainfall; CDMC model; Hunter River Catchment
- Identifier
- http://hdl.handle.net/1959.13/1330861
- Identifier
- uon:26495
- Identifier
- ISBN:9781922107497
- Language
- eng
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