TITLE:
Rainfall Variability over Ghana: Model versus Rain Gauge Observation
AUTHORS:
Francis Nkrumah, Nana Ama Browne Klutse, David Cudjoe Adukpo, Kwadwo Owusu, Kwesi Akumenyi Quagraine, Alfred Owusu, William Gutowski
KEYWORDS:
Rainfall Variability, Ghana, RegCM3, Temporal Rainfall Distribution, Rain Gauge Data
JOURNAL NAME:
International Journal of Geosciences,
Vol.5 No.7,
June
11,
2014
ABSTRACT: This
paper used the International Centre for Theoretical Physics (ICTP) Regional
Climate Model, Version 3 (RegCM3) and rain gauge data selected from the Ghana
Meteorological Agency (GMet) from 1990 to 2008 to investigate the extent and
nature of variability in the annual rainfall and pattern of the raining seasons
in Ghana. In the study, six meteorological stations selected from three rainfall
distribution zones according to the divisions of the GMet were used to study
the pattern of rainfall and its departure from the normal trend. The study also
assessed the performance of the RegCM3 simulation with reference to the
observed gauge data. Results confirmed the unimodal nature of the rainfall
annual cycle over the northern belt and bi-modal rainfall nature over the middle
and southern belts of Ghana. Negative departures of rainfall implying
consistent downward trend were observed at all the stations. Our analysis
showed that RegCM3 captured the average rainfall over Ghana but demonstrated an
underestimation as compared to the observed gauge data. The model also had
difficulty stimulating the departures accurately in direction and in magnitude
in all the stations except for Accra where RegCM3 simulated the right direction
of the departures.