Should seasonal rainfall forecasts be used for flood preparedness?
In light of strong encouragement for disaster managers to use climate services for flood preparation, we question whether seasonal rainfall forecasts should indeed be used as indicators of the likelihood of flooding. Here, we investigate the primary indicators of flooding at the seasonal timesca...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-09-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/21/4517/2017/hess-21-4517-2017.pdf |
| Summary: | In light of strong encouragement for disaster managers to use climate
services for flood preparation, we question whether seasonal rainfall
forecasts should indeed be used as indicators of the likelihood of flooding.
Here, we investigate the primary indicators of flooding at the seasonal
timescale across sub-Saharan Africa. Given the sparsity of hydrological
observations, we input bias-corrected reanalysis rainfall into the Global
Flood Awareness System to identify seasonal indicators of floodiness. Results
demonstrate that in some regions of western, central, and eastern Africa with
typically wet climates, even a perfect tercile forecast of seasonal total
rainfall would provide little to no indication of the seasonal likelihood of
flooding. The number of extreme events within a season shows the highest
correlations with floodiness consistently across regions. Otherwise, results
vary across climate regimes: floodiness in arid regions in southern and
eastern Africa shows the strongest correlations with seasonal average soil
moisture and seasonal total rainfall. Floodiness in wetter climates of
western and central Africa and Madagascar shows the strongest relationship
with measures of the intensity of seasonal rainfall. Measures of rainfall
patterns, such as the length of dry spells, are least related to seasonal
floodiness across the continent. Ultimately, identifying the drivers of
seasonal flooding can be used to improve forecast information for flood
preparedness and to avoid misleading decision-makers. |
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| ISSN: | 1027-5606 1607-7938 |