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Titel |
Multi-annual droughts in the English Lowlands: a review of their characteristics and climate drivers in the winter half-year |
VerfasserIn |
C. K. Folland, J. Hannaford, J. P. Bloomfield, M. Kendon, C. Svensson, B. P. Marchant, J. Prior, E. Wallace |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 5 ; Nr. 19, no. 5 (2015-05-20), S.2353-2375 |
Datensatznummer |
250120715
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Publikation (Nr.) |
copernicus.org/hess-19-2353-2015.pdf |
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Zusammenfassung |
The English Lowlands is a relatively dry, densely populated region in the
south-east of the UK in which water is used intensively. Consequently, parts
of the region are water-stressed and face growing water resource pressures.
The region is heavily dependent on groundwater and particularly vulnerable to
long, multi-annual droughts primarily associated with dry winters. Despite
this vulnerability, the atmospheric drivers of multi-annual droughts in the
region are poorly understood, an obstacle to developing appropriate drought
management strategies, including monitoring and early warning systems. To
advance our understanding, we assess known key climate drivers in the winter
half-year (October–March) and their likely relationships with multi-annual
droughts in the region. We characterise historic multi-annual drought
episodes back to 1910 for the English Lowlands using various meteorological
and hydrological data sets. Multi-annual droughts are identified using a
gridded precipitation series for the entire region, and refined using the
Standardized Precipitation Index (SPI), Standardized Streamflow Index (SSI)
and Standardized Groundwater level Index (SGI) applied to regional-scale
river flow and groundwater time series. We explore linkages between a range
of potential climatic driving factors and precipitation, river flow and
groundwater level indicators in the English Lowlands for the winter
half-year. The drivers or forcings include El Niño–Southern Oscillation
(ENSO), the North Atlantic tripole sea surface temperature (SST) pattern, the
Quasi-Biennial Oscillation (QBO), solar and volcanic forcing and the Atlantic
Multi-decadal Oscillation (AMO). As expected, no single driver convincingly
explains the occurrence of any multi-annual drought in the historical record.
However, we demonstrate, for the first time, an association between La
Niña episodes and winter rainfall deficits in some major multi-annual
drought episodes in the English Lowlands. We also show significant (albeit
relatively weak) links between ENSO and drought indicators applied to river
flow and groundwater levels. We also show that some of the other drivers
listed above are likely to influence English Lowlands rainfall. We conclude
by signposting a direction for this future research effort. |
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