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Statistical downscaling of precipitation for a selection of sites in Ireland employing a generalised linear modelling approach

Fealy, Rowan and Sweeney, John (2007) Statistical downscaling of precipitation for a selection of sites in Ireland employing a generalised linear modelling approach. International Journal of Climatology, 27 (15). pp. 2083-2094. ISSN 1097-0088

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Abstract

Producing plausible outputs from statistically downscaled models of daily precipitation remains a significant challenge when producing climate scenarios for impact assessments. This challenge arises primarily as a consequence of a number of difficulties encountered when working with higher resolution daily precipitation data. Precipitation receipts at a site tend to be largely heterogeneous over space and time as local factors, such as relief, play an important role in determining whether it rains or not. More crucially from the point of view of statistical analysis, daily precipitation data is rarely, if ever, normally distributed, resulting from a high frequency occurrence of low-fall events and a low frequency of high-fall events. Additionally, modelling precipitation requires a two-step procedure. First, precipitation occurrence must be modelled: then a model is fitted to precipitation quantities which describes the rainfall distribution for days on which precipitation occurs. This paper presents a technique that overcomes some of the difficulties encountered and produces plausible precipitation amounts for a selection of 14 sites in Ireland. Difficulties still exist with predicting extreme precipitation events, which tend to be underestimated by the methodology employed.

Item Type: Article
Additional Information: Copyright Royal Meteorological Society
Keywords: Statistical downscaling; Ireland; Synoptic stations; Generalised linear model; Gamma distribution; Logistic regression.
Subjects: Social Sciences > Geography
Item ID: 1876
Identification Number: 10.1002/joc.1506
Depositing User: Rowan Fealy
Date Deposited: 01 Mar 2010 17:51
Journal or Publication Title: International Journal of Climatology
Publisher: Royal Meteorological Society
Refereed: Yes
URI:

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