Seasonal prediction of lake inflows and rainfall in a hydro-electricity catchment, Waitaki river, New Zealand

Purdie, Jennifer Margaret; Bardsley, W. Earl

Seasonal prediction of lake inflows and rainfall in a hydro-electricity catchment, Waitaki river, New Zealand

dc.contributor.author	Purdie, Jennifer Margaret
dc.contributor.author	Bardsley, W. Earl
dc.date.accessioned	2010-02-16T20:17:44Z
dc.date.available	2010-02-16T20:17:44Z
dc.date.issued	2010
dc.description.abstract	The Waitaki River is located in the centre of the South Island of New Zealand, and hydro-electricity generated on the river accounts for 35-40% of New Zealand's electricity. Low inflows in 1992 and 2001 resulted in the threat of power blackouts. Improved seasonal rainfall and inflow forecasts will result in the better management of the water used in hydro-generation on a seasonal basis. Researchers have stated that two key directions in the fields of seasonal rainfall and streamflow forecasting are to a) decrease the spatial scale of forecast products, and b) tailor forecast products to end-user needs, so as to provide more relevant and targeted forecasts. Several season-ahead lake inflow and rainfall forecast models were calibrated for the Waitaki river catchment using statistical techniques to quantify relationships between land-ocean-atmosphere state variables and seasonally lagged inflows and rainfall. Techniques included principal components analysis and multiple linear regression, with cross-validation techniques applied to estimate model error and randomization techniques used to establish the significance of the skill of the models. Many of the models calibrated predict rainfall and inflows better than random chance and better than the long-term mean as a predictor. When compared to the range of all probable inflow seasonal totals (based on the 80-year recorded history in the catchment), 95% confidence limits around most model predictions offer significant skill. These models explain up to 19% of the variance in season-ahead rainfall and inflows in this catchment. Seasonal rainfall and inflow forecasting on a single catchment scale and focussed to end-user needs is possible with some skill in the South Island of New Zealand.	en
dc.format.mimetype	application/pdf
dc.identifier.citation	Purdie, J.M. & Bardsley, W.E. (2010). Seasonal prediction of lake inflows and rainfall in a hydro-electricity catchment, Waitaki river, New Zealand. International Journal of Climatology, 30(3), 372-389.	en
dc.identifier.doi	10.1002/joc.1897	en
dc.identifier.issn	1097-0088
dc.identifier.uri	https://hdl.handle.net/10289/3575
dc.language.iso	en
dc.publisher	John Wiley & Sons	en
dc.relation.isPartOf	International Journal of Climatology	en_NZ
dc.rights	This is is a preprint version of an artilce published in the International Journal of Climatology. Copyright 2009 Royal Meteorological Society.
dc.subject	New Zealand	en
dc.subject	seasonal forecasting	en
dc.subject	principal components analysis	en
dc.subject	multiple linear regression	en
dc.subject	cross-validation	en
dc.subject	randomization testing	en
dc.subject	rainfall	en
dc.subject	inflows	en
dc.title	Seasonal prediction of lake inflows and rainfall in a hydro-electricity catchment, Waitaki river, New Zealand	en
dc.type	Journal Article	en
pubs.begin-page	1	en_NZ
pubs.elements-id	34363
pubs.end-page	18	en_NZ
pubs.issue	3	en_NZ
pubs.volume	online	en_NZ