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| Titel |
The potential value of seasonal forecasts in a changing climate in southern Africa |
| VerfasserIn |
H. C. Winsemius, E. Dutra, F. A. Engelbrecht, E. Archer Van Garderen, F. Wetterhall, F. Pappenberger, M. G. F. Werner |
| 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 ; 18, no. 4 ; Nr. 18, no. 4 (2014-04-25), S.1525-1538 |
| Datensatznummer |
250120340
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| Publikation (Nr.) |
 copernicus.org/hess-18-1525-2014.pdf |
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| Zusammenfassung |
| Subsistence farming in southern Africa is vulnerable to extreme weather
conditions. The yield of rain-fed agriculture depends largely on
rainfall-related factors such as total seasonal rainfall, anomalous onsets
and lengths of the rainy season and the frequency of occurrence of dry
spells. Livestock, in turn, may be seriously impacted by climatic stress
with, for example, exceptionally hot days, affecting condition, reproduction,
vulnerability to pests and pathogens and, ultimately, morbidity and
mortality. Climate change may affect the frequency and severity of extreme
weather conditions, impacting on the success of subsistence farming. A
potentially interesting adaptation measure comprises the timely forecasting
and warning of such extreme events, combined with mitigation measures that
allow farmers to prepare for the event occurring. This paper investigates how
the frequency of extreme events may change in the future due to climate
change over southern Africa and, in more detail, the Limpopo Basin using a
set of climate change projections from several regional climate model
downscalings based on an extreme climate scenario. Furthermore, the paper
assesses the predictability of these indicators by seasonal meteorological
forecasts of the European Centre for Medium-Range Weather Forecasts (ECMWF)
seasonal forecasting system. The focus is on the frequency of dry spells as
well as the frequency of heat stress conditions expressed in the temperature
heat index. In areas where their frequency of occurrence increases in the
future and predictability is found, seasonal forecasts will gain importance
in the future, as they can more often lead to informed decision-making to
implement mitigation measures. The multi-model climate projections suggest
that the frequency of dry spells is not likely to increase substantially,
whereas there is a clear and coherent signal among the models of an increase
in the frequency of heat stress conditions by the end of the century. The
skill analysis of the seasonal forecast system demonstrates that there is a
potential to adapt to this change by utilizing the weather forecasts, given
that both indicators can be skilfully predicted for the December–February
season, at least 2 months ahead of the wet season. This is particularly the
case for predicting above-normal and below-normal conditions. The frequency
of heat stress conditions shows better predictability than the frequency of
dry spells. Although results are promising for end users on the ground,
forecasts alone are insufficient to ensure appropriate response. Sufficient
support for appropriate measures must be in place, and forecasts must be
communicated in a context-specific, accessible and understandable format. |
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