Wednesday, 14 January 2009
Intercomparison of the relationship between precipitation and mountain heights among gridded precipitation datasets
Hall 5 (Phoenix Convention Center)
Precipitation is strongly affected by topography. Orographic precipitation, which is forced by topography, is useful as water resources for human societies and is often harmful as natural disasters such as flooding. It is, therefore, important to estimate precipitation amount quantitatively over mountain regions and to understand its characteristics such as intensity and frequency. Climate models, which are a useful tool to project future climate change, needs to be validated the reproducibility of precipitation in terms of not only its amount but also its characteristics. However, observed precipitation datasets, which are derived from rain gauges, satellites or their combination, have not been sufficiently validated in terms of quantitative accuracy and precipitation characteristics. We conducted an intercomparison of the relationship between precipitation and topography among sixteen gridded precipitation datasets based on both rain gauges and satellites. In this study, we focused on the intercomparison on the relationship between precipitation and mountain heights. An analysis of the dependency of mean and accumulated precipitation on mountain heights shows that the spread of the dependency among satellite-based datasets is larger than that among gauge-based datasets and that the differences between them have both regional and seasonal variations. We also examine heavy precipitation, defined by 99 percentile of daily precipitation, for the datasets in which daily precipitation is available.
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