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You are here : eLibrary : IAHR World Congress Proceedings : 34th Congress - Brisbane (2011) : THEME 1: Extremes and Variability : Investigation into the suitability of using gridded data as a proxy for gauged data in hydrological ...
Investigation into the suitability of using gridded data as a proxy for gauged data in hydrological applications
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Gridded rainfall datasets have been used in many hydrological and climatological studies in Australia, including hydroclimatic forecasting, climate attribution studies and climate model performance assessments. Three Australia-wide monthly gridded rainfall datasets are currently available – the Bureau of Meteorology (BOM) dataset, the SILO dataset and the Australian Water Availability Project (AWAP) dataset. However, the question must be asked as to whether it is suitable to use gridded data as a proxy for observed data, given that gridded data is inherently ‘smoothed’. In this paper, this question is investigated through a statistical comparison between the AWAP, BOM and SILO gridded datasets and gauged data across South Australia. It is shown that the various gridded datasets may not suitably represent high or low rainfall events. To demonstrate the hydrological implications of this, a rainfall-runoff model is applied to one catchment in South Australia initially using gridded data as the source of rainfall input and then gauged rainfall data. The results indicate a markedly different runoff response associated with each of the different types of rainfall data suggesting that significant uncertainties are associated with the use of gridded data as a proxy for observed. It should be noted that this study does not seek to identify which gridded dataset is the “best”, as each data source has its pros and cons. Rather the intention is to quantify differences between various gridded data sources and how they compare with gauged data so that these differences can be considered and accounted for in studies that utilise gridded data. Ultimately, if key decisions are going to be based on the outputs of models that use gridded data, an estimate or at least understanding of the errors related to the gridded data should be made (Jeffrey et al, 2001).
File Size : 375,140 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 34th Congress - Brisbane (2011)
Article : THEME 1: Extremes and Variability
Date Published : 01/07/2011
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