- Title
- Climate-informed stochastic hydrological modeling: incorporating decadal-scale variability using paleo data
- Creator
- Henley, Benjamin J.; Thyer, Mark A.; Kuczera, George; Franks, Stewart W.
- Relation
- Water Resources Research Vol. 47
- Publisher Link
- http://dx.doi.org/10.1029/2010WR010034
- Publisher
- American Geophysical Union
- Resource Type
- journal article
- Date
- 2011
- Description
- A hierarchical framework for incorporating modes of climate variability into stochastic simulations of hydrological data is developed, termed the climate-informed multi-time scale stochastic (CIMSS) framework. A case study on two catchments in eastern Australia illustrates this framework. To develop an identifiable model characterizing long-term variability for the first level of the hierarchy, paleoclimate proxies, and instrumental indices describing the Interdecadal Pacific Oscillation (IPO) and the Pacific Decadal Oscillation (PDO) are analyzed. A new paleo IPO-PDO time series dating back 440 yr is produced, combining seven IPO-PDO paleo sources using an objective smoothing procedure to fit low-pass filters to individual records. The paleo data analysis indicates that wet/dry IPO-PDO states have a broad range of run lengths, with 90% between 3 and 33 yr and a mean of 15 yr. The Markov chain model, previously used to simulate oscillating wet/dry climate states, is found to underestimate the probability of wet/dry periods >5 yr, and is rejected in favor of a gamma distribution for simulating the run lengths of the wet/dry IPO-PDO states. For the second level of the hierarchy, a seasonal rainfall model is conditioned on the simulated IPO-PDO state. The model is able to replicate observed statistics such as seasonal and multiyear accumulated rainfall distributions and interannual autocorrelations. Mean seasonal rainfall in the IPO-PDO dry states is found to be 15%–28% lower than the wet state at the case study sites. In comparison, an annual lag-one autoregressive model is unable to adequately capture the observed rainfall distribution within separate IPO-PDO states.
- Subject
- IPO; PDO; climate variability; hydrology; rainfall; stochastic
- Identifier
- uon:9505
- Identifier
- http://hdl.handle.net/1959.13/922200
- Identifier
- ISSN:0043-1397
- Language
- eng
- Full Text
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