Revisiting historical climatic signals to better explore the future: prospects of water cycle changes in Central Sahel
Rainfall and climatic conditions are the main drivers of natural and cultivated vegetation productivity in the semiarid region of Central Sahel. In a context of decreasing cultivable area per capita, understanding and predicting changes in the water cycle are crucial. Yet, it remains challenging...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
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| Series: | Proceedings of the International Association of Hydrological Sciences |
| Online Access: | https://www.proc-iahs.net/371/195/2015/piahs-371-195-2015.pdf |
| Summary: | Rainfall and climatic conditions are the main drivers of natural and
cultivated vegetation productivity in the semiarid region of Central Sahel.
In a context of decreasing cultivable area per capita, understanding and
predicting changes in the water cycle are crucial. Yet, it remains
challenging to project future climatic conditions in West Africa since there
is no consensus on the sign of future precipitation changes in simulations
coming from climate models.
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The Sahel region has experienced severe climatic changes in the past 60 years
that can provide a first basis to understand the response of the water
cycle to non-stationary conditions in this part of the world. The objective
of this study was to better understand the response of the water cycle to
highly variable climatic regimes in Central Sahel using historical climate
records and the coupling of a land surface energy and water model with a
vegetation model that, when combined, simulated the Sahelian water, energy
and vegetation cycles. To do so, we relied on a reconstructed long-term
climate series in Niamey, Republic of Niger, in which three precipitation
regimes can be distinguished with a relative deficit exceeding 25% for
the driest period compared to the wettest period. Two temperature scenarios
(+2 and +4 °C) consistent with future warming
scenarios were superimposed to this climatic signal to generate six virtual
future 20-year climate time series. Simulations by the two coupled models forced
by these virtual scenarios showed a strong response of the water budget and
its components to temperature and precipitation changes, including decreases
in transpiration, runoff and drainage for all scenarios but those with
highest precipitation. Such climatic changes also strongly impacted soil
temperature and moisture. This study illustrates the potential of using the
strong climatic variations recorded in the past decades to better understand
potential future climate variations. |
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| ISSN: | 2199-8981 2199-899X |