Investigating uncertainties in global gridded datasets of climate extremes

We assess the effects of different methodological choices made during the construction of gridded data sets of climate extremes, focusing primarily on HadEX2. Using global land-surface time series of the indices and their coverage, as well as uncertainty maps, we show that the choices which have the...

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Main Authors: R. J. H. Dunn, M. G. Donat, L. V. Alexander
Format: Article
Language:English
Published: Copernicus Publications 2014-12-01
Series:Climate of the Past
Online Access:http://www.clim-past.net/10/2171/2014/cp-10-2171-2014.pdf
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spelling doaj-90664abaf84f47d8a016e603697f50c22020-11-24T23:58:09ZengCopernicus PublicationsClimate of the Past1814-93241814-93322014-12-011062171219910.5194/cp-10-2171-2014Investigating uncertainties in global gridded datasets of climate extremesR. J. H. Dunn0M. G. Donat1L. V. Alexander2Met Office Hadley Centre, FitzRoy Road, Exeter, EX1 3PB, UKARC Centre of Excellence for Climate System Science and Climate Change Research Centre, UNSW, Sydney, NSW 2052, AustraliaARC Centre of Excellence for Climate System Science and Climate Change Research Centre, UNSW, Sydney, NSW 2052, AustraliaWe assess the effects of different methodological choices made during the construction of gridded data sets of climate extremes, focusing primarily on HadEX2. Using global land-surface time series of the indices and their coverage, as well as uncertainty maps, we show that the choices which have the greatest effect are those relating to the station network used or that drastically change the values for individual grid boxes. The latter are most affected by the number of stations required in or around a grid box and the gridding method used. Most parametric changes have a small impact, on global and on grid box scales, whereas structural changes to the methods or input station networks may have large effects. On grid box scales, trends in temperature indices are very robust to most choices, especially in areas which have high station density (e.g. North America, Europe and Asia). The precipitation indices, being less spatially correlated, can be more susceptible to methodological choices, but coherent changes are still clear in regions of high station density. Regional trends from all indices derived from areas with few stations should be treated with care. On a global scale, the linear trends over 1951–2010 from almost all choices fall within the 5–95th percentile range of trends from HadEX2. This demonstrates the robust nature of HadEX2 and related data sets to choices in the creation method.http://www.clim-past.net/10/2171/2014/cp-10-2171-2014.pdf
collection DOAJ
language English
format Article
sources DOAJ
author R. J. H. Dunn
M. G. Donat
L. V. Alexander
spellingShingle R. J. H. Dunn
M. G. Donat
L. V. Alexander
Investigating uncertainties in global gridded datasets of climate extremes
Climate of the Past
author_facet R. J. H. Dunn
M. G. Donat
L. V. Alexander
author_sort R. J. H. Dunn
title Investigating uncertainties in global gridded datasets of climate extremes
title_short Investigating uncertainties in global gridded datasets of climate extremes
title_full Investigating uncertainties in global gridded datasets of climate extremes
title_fullStr Investigating uncertainties in global gridded datasets of climate extremes
title_full_unstemmed Investigating uncertainties in global gridded datasets of climate extremes
title_sort investigating uncertainties in global gridded datasets of climate extremes
publisher Copernicus Publications
series Climate of the Past
issn 1814-9324
1814-9332
publishDate 2014-12-01
description We assess the effects of different methodological choices made during the construction of gridded data sets of climate extremes, focusing primarily on HadEX2. Using global land-surface time series of the indices and their coverage, as well as uncertainty maps, we show that the choices which have the greatest effect are those relating to the station network used or that drastically change the values for individual grid boxes. The latter are most affected by the number of stations required in or around a grid box and the gridding method used. Most parametric changes have a small impact, on global and on grid box scales, whereas structural changes to the methods or input station networks may have large effects. On grid box scales, trends in temperature indices are very robust to most choices, especially in areas which have high station density (e.g. North America, Europe and Asia). The precipitation indices, being less spatially correlated, can be more susceptible to methodological choices, but coherent changes are still clear in regions of high station density. Regional trends from all indices derived from areas with few stations should be treated with care. On a global scale, the linear trends over 1951–2010 from almost all choices fall within the 5–95th percentile range of trends from HadEX2. This demonstrates the robust nature of HadEX2 and related data sets to choices in the creation method.
url http://www.clim-past.net/10/2171/2014/cp-10-2171-2014.pdf
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