An Evaluation of the Consistency of Extremes in Gridded Precipitation Data Sets

TitleAn Evaluation of the Consistency of Extremes in Gridded Precipitation Data Sets
Publication TypeJournal Article
Year of Publication2018
JournalClimate Dynamics
Date Published03/2018
Abstract / Summary

Noting a strong imperative to understand precipitation extremes, and that considerable uncertainty affects observational data sets, this paper compares the representation of extremes in a number of widely used daily gridded products, derived from rain gauge data, satellite retrieval and reanalysis for the conterminous United States. An analysis is based upon the concept of “tail dependence” arising in multivariate extreme value theory, and we infer the level of temporal dependence in the joint tail of the precipitation probability distribution for pairwise comparisons of products. In this way, we consider the range of products more like an ensemble and examine the relationships between members, and do not attempt to define, or compare products to, some ground truth. Linear correlation between products is also computed. Considerable discrepancy between groups of products, both annually and seasonally, is linked to source data and complex terrain. In particular, products based on rain gauge data showed remarkable similarity, but differed considerably, showing almost total loss of extremal dependence during DJF in mountainous regions, when compared with satellite products. Additionally, simulated re-forecasts revealed reasonable temporal agreement with large scale generated extremes. The diversity and extent of discrepancies identified across all products raises important questions about their use, and we urge caution, particularly for products derived from satellite data.

URLhttps://climatemodeling.science.energy.gov/system/files/private/highlights/publications/Timmermans-et-al2018feb_highlight_ClimDyn.pdf
DOI10.1007/s00382-018-4537-0
Journal: Climate Dynamics
Year of Publication: 2018
Date Published: 03/2018

Noting a strong imperative to understand precipitation extremes, and that considerable uncertainty affects observational data sets, this paper compares the representation of extremes in a number of widely used daily gridded products, derived from rain gauge data, satellite retrieval and reanalysis for the conterminous United States. An analysis is based upon the concept of “tail dependence” arising in multivariate extreme value theory, and we infer the level of temporal dependence in the joint tail of the precipitation probability distribution for pairwise comparisons of products. In this way, we consider the range of products more like an ensemble and examine the relationships between members, and do not attempt to define, or compare products to, some ground truth. Linear correlation between products is also computed. Considerable discrepancy between groups of products, both annually and seasonally, is linked to source data and complex terrain. In particular, products based on rain gauge data showed remarkable similarity, but differed considerably, showing almost total loss of extremal dependence during DJF in mountainous regions, when compared with satellite products. Additionally, simulated re-forecasts revealed reasonable temporal agreement with large scale generated extremes. The diversity and extent of discrepancies identified across all products raises important questions about their use, and we urge caution, particularly for products derived from satellite data.

DOI: 10.1007/s00382-018-4537-0
Citation:
Timmermans, B, MF Wehner, D Cooley, T O'Brien, and H Krishnan.  2018.  "An Evaluation of the Consistency of Extremes in Gridded Precipitation Data Sets."  Climate Dynamics.  https://doi.org/10.1007/s00382-018-4537-0.