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| Titel |
Spatial and seasonal responses of precipitation in the Ganges and Brahmaputra river basins to ENSO and Indian Ocean dipole modes: implications for flooding and drought |
| VerfasserIn |
M. S. Pervez, G. M. Henebry |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Sciences ; 15, no. 1 ; Nr. 15, no. 1 (2015-01-28), S.147-162 |
| Datensatznummer |
250119278
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| Publikation (Nr.) |
 copernicus.org/nhess-15-147-2015.pdf |
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| Zusammenfassung |
| We evaluated the spatial and seasonal responses of precipitation in the
Ganges and Brahmaputra basins as modulated by the El Niño Southern
Oscillation (ENSO) and Indian Ocean Dipole (IOD) modes using Global
Precipitation Climatology Centre (GPCC) full data reanalysis of monthly
global land-surface precipitation data from 1901 to 2010 with a spatial
resolution of 0.5° × 0.5°. The GPCC monthly total
precipitation climatology targeting the period 1951–2000 was used to
compute gridded monthly anomalies for the entire time period. The gridded
monthly anomalies were averaged for the years influenced by combinations of
climate modes. Occurrences of El Niño alone significantly reduce (88%
of the long-term average (LTA)) precipitation during the monsoon months in
the western and southeastern Ganges Basin. In contrast, occurrences of La
Niña and co-occurrences of La Niña and negative IOD events
significantly enhance (110 and 109% of LTA in the Ganges and
Brahmaputra Basin, respectively) precipitation across both basins. When El
Niño co-occurs with positive IOD events, the impacts of El Niño on
the basins' precipitation diminishes. When there is no active ENSO or IOD
events (occurring in 41 out of 110 years), precipitation remains below average (95% of LTA) in
the agriculturally intensive areas of Haryana, Uttar Pradesh, Rajasthan,
Madhya Pradesh, and Western Nepal in the Ganges Basin, whereas precipitation
remains average to above average (104% of LTA) across the Brahmaputra
Basin. This pattern implies that a regular water deficit is likely,
especially in the Ganges Basin, with implications for the agriculture sector
due to its reliance on consistent rainfall for successful production.
Historically, major droughts occurred during El Niño and co-occurrences
of El Niño and positive IOD events, while major flooding occurred during
La Niña and co-occurrences of La Niña and negative IOD events in the
basins. This observational analysis will facilitate well-informed decision
making in minimizing natural hazard risks and climate impacts on
agriculture, and supports development of strategies ensuring optimized use
of water resources in best management practice under a changing climate. |
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