TITLE:
Multi-Scale Characteristics of Precipitation and Temperature over West Africa Using SMHI-RCA Driven by GCMs under RCP8.5
AUTHORS:
Abdoulaye Sarr
KEYWORDS:
Downscaling, Scenarios, Climate Variability and Change, Onset, Seasonal Cycle, West Africa
JOURNAL NAME:
American Journal of Climate Change,
Vol.6 No.3,
August
23,
2017
ABSTRACT: In this paper, we use simulations from the Swedish Meteorological and Hydrological Institute (SMHI) regional climate model (RCM) version 3.5 (SMHI-RCA3.5) following a multi-GCM boundary forcing approach. The model is run at a horizontal resolution of 50 km on the CORDEX-AFRICA domain. Key characteristics of precipitation, mean temperature and its extremes (minimum and maximum temperature) have been investigated over West Africa and on 3 designed sub-domains, the Sahel (SAH), the Senegal-Gambia (SEN) and the Gulf of Guinea (GOG). The analysis covers a historical period 1981-2005 and two future time slices, an intermediate term (IT) 2031-2055 and a fat term (FT) 2071-2095, under the Representative Concentration Pathways 8.5 (RCP8.5). The regional climate model RCA, forced by the reanalysis ERA-Interim, 6 CMIP5 GCMs and their ensemble, reproduces realistically the climatology of precipitation and temperatures over West Africa. Compared to observed datasets GPCP for precipitation and CRU for temperature, the ensemble outperforms both other GCMs and the verification model (ERA-Interim). The major biases in precipitation are the early onset over the Sahel and the little dry season (LDS), from mid-July to mid-September over the Gulf of Guinea, and a few models either overestimate and/or reflect rather poorly. The strong warming in extreme temperatures (minimum and maximum) combined with the drying mainly over Western Sahel (SEN) found in this study will very likely impact notably a vital sector like agriculture, both during the near and far terms.