High-resolution simulations of West African climate using regional climate model (RegCM3) with different lateral boundary conditions

M. B. Sylla, A. T. Gaye, J. S. Pal, Gregory S. Jenkins, X. Q. Bi

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

To downscale climate change scenarios, long-term regional climatologies employing global model forcing are needed for West Africa. As a first step, this work examines present-day integrations (1981-2000) with a regional climate model (RCM) over West Africa nested in both reanalysis data and output from a coupled atmospheric-ocean general circulation model (AOGCM). Precipitation and temperature from both simulations are compared to the Climate Research Unit observations. Their spatial distributions are shown to be realistic. Annual cycles are considerably correlated. Simulations are also evaluated with respect to the driving large-scale fields. RCM offers some improvements compared to the AOGCM driving field. Evaluation of seasonal precipitation biases reveals that RCM dry biases are highest on June-August around mountains. They are associated to cold biases in temperature which, in turn, are connected to wet biases in precipitation outside orographic zones. Biases brought through AOGCM forcing are relatively low. Despite these errors, the simulations produce encouraging results and show the ability of the AOGCM to drive the RCM for future projections.

Original languageEnglish (US)
Pages (from-to)293-314
Number of pages22
JournalTheoretical and Applied Climatology
Volume98
Issue number3-4
DOIs
StatePublished - Jan 1 2009

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regional climate
general circulation model
climate modeling
boundary condition
climate
ocean
simulation
annual cycle
temperature
spatial distribution
climate change
mountain
West Africa

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Cite this

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abstract = "To downscale climate change scenarios, long-term regional climatologies employing global model forcing are needed for West Africa. As a first step, this work examines present-day integrations (1981-2000) with a regional climate model (RCM) over West Africa nested in both reanalysis data and output from a coupled atmospheric-ocean general circulation model (AOGCM). Precipitation and temperature from both simulations are compared to the Climate Research Unit observations. Their spatial distributions are shown to be realistic. Annual cycles are considerably correlated. Simulations are also evaluated with respect to the driving large-scale fields. RCM offers some improvements compared to the AOGCM driving field. Evaluation of seasonal precipitation biases reveals that RCM dry biases are highest on June-August around mountains. They are associated to cold biases in temperature which, in turn, are connected to wet biases in precipitation outside orographic zones. Biases brought through AOGCM forcing are relatively low. Despite these errors, the simulations produce encouraging results and show the ability of the AOGCM to drive the RCM for future projections.",
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High-resolution simulations of West African climate using regional climate model (RegCM3) with different lateral boundary conditions. / Sylla, M. B.; Gaye, A. T.; Pal, J. S.; Jenkins, Gregory S.; Bi, X. Q.

In: Theoretical and Applied Climatology, Vol. 98, No. 3-4, 01.01.2009, p. 293-314.

Research output: Contribution to journalArticle

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