Klutse N.A.B.,Ghana Atomic Energy Commission |
Sylla M.B.,West African Science Service Center on Climate Change and Adapted Landuse |
Sylla M.B.,Loyola Marymount University |
Diallo I.,Cheikh Anta Diop University |
And 14 more authors.
Theoretical and Applied Climatology | Year: 2016
We analyze and intercompare the performance of a set of ten regional climate models (RCMs) along with the ensemble mean of their statistics in simulating daily precipitation characteristics during the West African monsoon (WAM) period (June–July–August–September). The experiments are conducted within the framework of the COordinated Regional Downscaling Experiments for the African domain. We find that the RCMs exhibit substantial differences that are associated with a wide range of estimates of higher-order statistics, such as intensity, frequency, and daily extremes mostly driven by the convective scheme employed. For instance, a number of the RCMs simulate a similar number of wet days compared to observations but greater rainfall intensity, especially in oceanic regions adjacent to the Guinea Highlands because of a larger number of heavy precipitation events. Other models exhibit a higher wet-day frequency but much lower rainfall intensity over West Africa due to the occurrence of less frequent heavy rainfall events. This indicates the existence of large uncertainties related to the simulation of daily rainfall characteristics by the RCMs. The ensemble mean of the indices substantially improves the RCMs’ simulated frequency and intensity of precipitation events, moderately outperforms that of the 95th percentile, and provides mixed benefits for the dry and wet spells. Although the ensemble mean improved results cannot be generalized, such an approach produces encouraging results and can help, to some extent, to improve the robustness of the response of the WAM daily precipitation to the anthropogenic greenhouse gas warming. © 2015, Springer-Verlag Wien.
Gbobaniyi E.,Obafemi Awolowo University |
Gbobaniyi E.,Swedish Meteorological and Hydrological Institute |
Sarr A.,Agence Nationale de lAviation Civile et de Meteorologie du Senegal ANACIM |
Sylla M.B.,Loyola Marymount University |
And 9 more authors.
International Journal of Climatology | Year: 2014
We examine the ability of an ensemble of 10 Regional Climate Models (RCMs), driven by ERA-Interim reanalysis, in skillfully reproducing key features of present-day precipitation and temperature (1990-2008) over West Africa. We explore a wide range of time scales spanning seasonal climatologies, annual cycles and interannual variability, and a number of spatial scales covering the Sahel, the Gulf of Guinea and the entire West Africa. We find that the RCMs show acceptable performance in simulating the spatial distribution of the main precipitation and temperature features. The occurrence of the West African Monsoon jump, the intensification and northward shift of the Saharan Heat Low (SHL), during the course of the year, are shown to be realistic in most RCMs. They also capture the mean annual cycle of precipitation and temperature, including, single and double-peaked rainy seasons, in terms of timing and amplitude over the homogeneous sub-regions. However, we should emphasize that the RCMs exhibit some biases, which vary considerably in both magnitude and spatial extent from model to model. The interannual variability of seasonal anomalies is best reproduced in temperature rather than precipitation. The ensemble mean considerably improves the skill of most of the individual RCMs. This highlights the importance of performing multi-model assessment in properly estimating the response of the West African climate to global warming at seasonal, annual and interannual time scales. © 2013 Royal Meteorological Society.
Fink A.H.,University of Cologne |
Agusti-Panareda A.,ECMWF |
Parker D.J.,University of Leeds |
Lafore J.-P.,Meteo - France |
And 16 more authors.
Atmospheric Science Letters | Year: 2011
Real-time surface and upper-air observations are crucial to the analysis and forecasting of the West African monsoon (WAM). This paper will focus on the African Monsoon-Multidisciplinary Analyses (AMMA)-driven reactivation and modernisation of the radiosonde network over West Africa, its potential long-term impact on upper-air operations in the region, the influence of the additional data in WAM analyses and forecasting, and the AMMA-related development and usage of the West African Analysis/Forecasting (WASA/F) forecast method. Copyright © 2011 Royal Meteorological Society.