An evaluation of the statistics of rainfall extremes in rain gauge observations, and satellite-based and reanalysis products using universal multifractals
Abstract
Confidence in the estimation of variations in the frequency of extreme events, and
specifically extreme precipitation, in response to climate variability and change
is key to the development of adaptation strategies. One challenge to establishing
a statistical baseline of rainfall extremes is the disparity among the types of datasets
(observations versus model simulations) and their specific spatial and temporal resolutions.
In this context, a multifractal framework was applied to three distinct types of rainfall
data to assess the statistical differences among time series corresponding to individual
rain gauge measurements alone-National Climatic Data Center (NCDC), model-based reanalysis
[North America Regional Reanalysis (NARR) grid points], and satellite-based precipitation
products [Global Precipitation Climatology Project (GPCP) pixels]-for the western
United States (west of 105°W). Multifractal analysis provides general objective metrics
that are especially adept at describing the statistics of extremes of time series.
This study shows that, as expected, multifractal parameters estimated from the NCDC
rain gauge dataset map the geography of known hydrometeorological phenomena in the
major climatic regions, including the strong orographic gradients from west to east;
whereas the NARR parameters reproduce the spatial patterns of NCDC parameters, but
the frequency of large rainfall events, the magnitude of maximum rainfall, and the
mean intermittency are underestimated. That is, the statistics of the NARR climatology
suggest milder extremes than those derived from rain gauge measurements. The spatial
distributions of GPCP parameters closely match the NCDC parameters over arid and semiarid
regions (i.e., the Southwest), but there are large discrepancies in all parameters
in the midlatitudes above 40°N because of reduced sampling. This study provides an
alternative independent backdrop to benchmark the use of reanalysis products and satellite
datasets to assess the effect of climate change on extreme rainfall. © 2010 American
Meteorological Society.
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Journal articlePermalink
https://hdl.handle.net/10161/4265Published Version (Please cite this version)
10.1175/2009JHM1142.1Publication Info
Sun, X; & Barros, AP (2010). An evaluation of the statistics of rainfall extremes in rain gauge observations, and
satellite-based and reanalysis products using universal multifractals. Journal of Hydrometeorology, 11(2). pp. 388-404. 10.1175/2009JHM1142.1. Retrieved from https://hdl.handle.net/10161/4265.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Ana P. Barros
Edmund T. Pratt, Jr. School Distinguished Professor Emeritus of Civil and Environmental
Engineering
Professor Ana Barros was born in Africa, grew up in Angola and Portugal, and has lived
almost all of her adult life in the United States. She attended the Faculty of Engineering
of the University of O’Porto where she obtained a summa cum laude Diploma in Civil
Engineering with majors in Structures and Hydraulics in 1985, and a M.Sc. degree in
Ocean Engineering in 1988 with a thesis focusing on numerical modeling of sediment
transport in estuaries and coastal regions. In 1990, Dr. Barros

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