The Open Access Journal of Science and Technology

Abstract

Modelling West African Total Precipitation Depth: A Statistical Approach

Author(s): S.Sovoe

Even though several reports over the past few decades indicate an increasing aridity over West Africa, attempts to establishthecontrollingfactor(s)havenotbeensuccessful.ThetraditionalbeliefofthepositionoftheInter-tropicalConvergence Zone (ITCZ) as the predominant factor over the region has been refuted by recent findings. Changes in major atmospheric circulations such as African Easterly Jet (AEJ) and Tropical Easterly Jet (TEJ) are being cited as major precipitation driving forces over the region. Thus, any attempt to predict long term precipitation events over the region using Global Circulation or LocalCirculationModelscouldbeflawedasthecontrollingfactorsarenotfullyelucidatedyet.Successfulpredictioneffortmay requiremodelswhichdependonpasteventsastheirinputsasinthecaseoftimeseriesmodelssuchasAutoregressiveIntegrated Moving Average (ARIMA) model. In this study, historical precipitation data was imported as time series data structure into an R programminglanguageandwasusedtobuildappropriateSeasonalMultiplicativeAutoregressiveIntegratedMovingAverage model,ARIMA(𝑝,𝑑,𝑞)∗(𝑃,𝐷,𝑄).ThemodelwasthenusedtopredictlongtermprecipitationeventsovertheGhanaiansegment oftheVoltaBasinwhichcouldbeusedinplanningandimplementationofdevelopmentpolicies

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