Reconstructing long-term records of UK drought and analysis of variability: 1697-2013



Todd, Beverley
Reconstructing long-term records of UK drought and analysis of variability: 1697-2013. PhD thesis, University of Liverpool.

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Abstract

Droughts are one of the most widespread and complex natural hazards, and remain poorly understood in the context of the United Kingdom. Although the UK is perceived as a relatively water rich country, droughts are a recurrent feature of its climate, causing widespread and serious environmental and economic impacts. Current understanding of drought risk is often based on relatively short records, and/or a small number of specific contemporary case study events from the last couple of decades (e.g. 1976). This study addresses this problem through the development of long (>150 year) meteorological drought records reconstructed using the self-calibrating Palmer Drought Severity Index (scPDSI). The index was calculated using long duration temperature and rainfall records. New rainfall series were generated for Carlisle and Chatsworth, existent rainfall series were extended for Kew, Spalding, Manchester, Edinburgh and Oxford. Additional rainfall series were kindly provided for Appleby and Durham. Temperature series for the Lancashire Plain, Oxford, Edinburgh and Durham were also extended. Where appropriate the newly developed and existing series were evaluated and tested to ensure homogeneity. The drought reconstructions identify multiple drought-rich periods, particularly in the eighteenth and twentieth centuries, with an increasing tendency towards more severe droughts during the latter period. Prolonged rainfall deficiencies are found to be the primary cause of severe droughts, with rising temperatures exacerbating the rainfall conditioned drought pattern. Cycles at the 6-10 year period identify a sub-decadal to decadal signal during the more drought-rich periods, which can be interpreted as reflecting large scale modes of climate variability. Analysis of the spatial variability of droughts finds that whilst severe events predominantly display spatial coherence, there are notable variations in drought characteristics (severity and duration) that reflect intra- and interregional variability in drought behaviour. In part this can be attributed to localised variations in rainfall and distance between sites. This study extends the temporal range of previous drought studies and places recent drought events in a longer context, improving upon existing ‘benchmark’ drought analyses; with far-reaching implications for local, national and continental scale reduction of drought vulnerability and risk.

Item Type: Thesis (PhD)
Additional Information: Date: 2014-09 (completed)
Subjects: ?? G1 ??
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Depositing User: Symplectic Admin
Date Deposited: 11 Sep 2015 14:09
Last Modified: 17 Dec 2022 01:54
DOI: 10.17638/02011366
URI: https://livrepository.liverpool.ac.uk/id/eprint/2011366