The relationship between African easterly waves and daily rainfall over West Africa: observations and regional climate simulations

Verfasser / Beitragende:
[Julien Crétat, Edward Vizy, Kerry Cook]
Ort, Verlag, Jahr:
2015
Enthalten in:
Climate Dynamics, 44/1-2(2015-01-01), 385-404
Format:
Artikel (online)
ID: 605474192
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024 7 0 |a 10.1007/s00382-014-2120-x  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00382-014-2120-x 
245 0 4 |a The relationship between African easterly waves and daily rainfall over West Africa: observations and regional climate simulations  |h [Elektronische Daten]  |c [Julien Crétat, Edward Vizy, Kerry Cook] 
520 3 |a The relationship between summer African easterly waves (AEWs) and daily rainfall is assessed in West Africa for 1998-2008 using various reanalyses, satellite-derived rainfall products, and a regional climate model (RCM) run at 90- and 30-km resolutions. 3-5 and 6-9day AEWs are extracted by filtering daily 700hPa meridional wind time series at 1°W and 11.5°N, and 1°W and 17.5°N, respectively. Both observed and simulated rainfall anomalies are of larger magnitude over West Africa during 3-5-d than 6-9-d AEWs. The RCM simulates larger rainfall rates in phase with the 3-5-d wave trough instead of ahead, unlike the observations, and overestimates the intensity and spatial coverage of rainfall associated with 6-9-d AEWs. The observed and simulated co-variability between 3-5-d (6-9-d) AEW activity and daily rainfall is strong (weak) and mostly located south (north) of 15°N. However, the RCM overestimates the spatial coverage of the AEW-rainfall relationship in the longitudinal (latitudinal) direction in the case of 3-5-d (6-9-d) AEWs. Observed and simulated daily intense rainfall events, extracted using a percentile threshold approach, are mostly located south of 15°N during summer. The observed relationship between their frequency of occurrence and active 3-5-d AEWs is maximal west of 8°E, while extends up to southern Chad in both RCM simulations. Their magnitude is also largely overestimated by the RCM, indicating an exaggerated coupling between the wave activity and the convection. Finally, observed and simulated 3-5-d AEWs establish the most favorable synoptic conditions for the development of intense rainfall events over West Africa. 
540 |a Springer-Verlag Berlin Heidelberg, 2014 
690 7 |a African easterly waves  |2 nationallicence 
690 7 |a Daily intense/extreme rainfall events  |2 nationallicence 
690 7 |a Regional climate model  |2 nationallicence 
690 7 |a Sahel  |2 nationallicence 
690 7 |a West Africa  |2 nationallicence 
700 1 |a Crétat  |D Julien  |u Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, 78712, Austin, TX, USA  |4 aut 
700 1 |a Vizy  |D Edward  |u Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, 78712, Austin, TX, USA  |4 aut 
700 1 |a Cook  |D Kerry  |u Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, 78712, Austin, TX, USA  |4 aut 
773 0 |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 44/1-2(2015-01-01), 385-404  |x 0930-7575  |q 44:1-2<385  |1 2015  |2 44  |o 382 
856 4 0 |u https://doi.org/10.1007/s00382-014-2120-x  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00382-014-2120-x  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Crétat  |D Julien  |u Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, 78712, Austin, TX, USA  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Vizy  |D Edward  |u Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, 78712, Austin, TX, USA  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Cook  |D Kerry  |u Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, 78712, Austin, TX, USA  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Climate Dynamics  |d Springer Berlin Heidelberg  |g 44/1-2(2015-01-01), 385-404  |x 0930-7575  |q 44:1-2<385  |1 2015  |2 44  |o 382