socio-economic sector of West African countries is rain-fed agriculture driven.
Information regarding the onset, cessation and duration of the rainy season is
thus, very essential. In this paper, a comparison of the onset, cessation and
duration of the rainy season has been carried out using simulated rainfall data
from the fourth generation Regional Climate Model (RegCM4) and rain gauge
measurements from Ghana Meteorological Agency (GMet), covering a period of 1998
to 2012. Similar onset and cessation dates were seen in both the simulated and
guage rainfall measurements for the various agro-ecological zones, resulting in
similar duration of the rainy season. The average duration of the rainy season
were less than 200 days for the savannah and coastal zones whereas the duration
of the rainy season were beyond 200 days for the forest and transition zones.
The bias of these comparisons was less than 30 days and the root mean square
error (RMSE) values were less than 15 days for all stations, except Saltpond.
The Pearson’s correlation (r) typically ranged between 0.4 and 0.8. However,
negative correlations were observed for Tamale in the savannah zone, and the
entire coastal zone. These findings are indications that RegCM4 has the
potential to clearly simulate the movement of the rain belt, and thus, could
fairly determine the onset, cessation and duration of the rainy season. The
findings have significant contributions to effective water resource management
and food security in Ghana, as the thriving of these sectors depend on the
dynamics of the rainfall seasons.
Amekudzi, L.K., Yamba, E., Preko, K., Asare, E.O., Aryee, J., Baidu, M. and Codjoe, N.A.S. (2015) Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana. Ecological Impacts of Climate Change, 3, 416-434. http://dx.doi.org/10.3390/cli3020416
Manzanas, R., Amekudzi, L., Preko, K., Herrera, S. and Gutierrez, J. (2014) A Comparison of Methods to Determine the Onset of the Growing Season in Nigeria. Climatic Change, 124, 805-819. http://dx.doi.org/10.1007/s10584-014-1100-9
Adejuwon, J., Balogun, E. and Adejuwon, S. (1990) On the Annual and Seasonal Patterns of Rainfall Uctuations in Sub-Saharan West Africa. International Journal of Climatology, 10, 839-848. http://dx.doi.org/10.1002/joc.3370100806
Odekunle, T. (2006) Determining Rainy Season Onset and Retreat over Nigeria from Precipitation Amount and Number of Rainy Days. Theoretical and Applied Climatology, 83, 193-201. http://dx.doi.org/10.1007/s00704-005-0166-8
Le Barbe, L., Lebel, T. and Tapsoba, D. (2002) Rainfall Variability in West Africa during the Years 1950-90. Int. J. Climate, 15, 187-202. http://dx.doi.org/10.1175/1520-0442(2002)015<0187:RVIWAD>2.0.CO;2
Omotosho, J. (2002) Synoptic Meteorology: Pathway to Seasonal Rainfall Prediction for Sustainable Agriculture and Effective Water Resources Management in West Africa but Nigeria in Particular. Journal of the Nigerian Meteorological Society, 3, 81-89.
Giorgi, F., Coppola, E., Solomon, F., Mariotti, L., Sylla, M., Bi, X., Elguindi, N., Diro, G., Nair, V., Giuliani, G., Turuncoglu, U., Cozzini, S., Guttler, I., Brien, T., Tawfik, A., Shalaby, A., Zakey, A., Steiner, A., Stordal, F., Sloan, L. and Brankovic, C. (2012) RegCM4: Model Description and Preliminary Tests over Multiple CORDEX Domains. Climate Research, 52, 7-29. http://dx.doi.org/10.3354/cr01018
Browne, N. and Sylla, M. (2012) Regional Climate Model Sensitivity to Domain Size for the Simulation of the West African Summer Monsoon Rainfall. International Journal of Geophysics, 2012, 1-17. http://dx.doi.org/10.1155/2012/625831
Mounier, F., Janicot, S. and Kiladis, G.N. (2008) The West African Monsoon Dynamics Part III: The Quasi-Biweekly zonal Dipole. Journal of Climate, 21, 1911-1928. http://dx.doi.org/10.1175/2007JCLI1706.1
Qian, J.H., Robertson, A.W. and Moron, V. (2010) Interactions among ENSO, the Monsoons, and Diurnal Cycle in Rainfall Variability over Java, Indonesia. J Atmos Sci, 67, 35093524. http://dx.doi.org/10.1175/2010JAS3348.1
Dodd, D. and Jolliffe, I. (2001) Early Detection of the Start of the Wet Season in Semiarid Tropical Climates of Western Africa. International Journal of Climatology, 21, 1251-1262. http://dx.doi.org/10.1002/joc.640
Amekudzi, L.K., Bracher, A., Bramstedt, K., Rozanov, A., Bovensmann, H. and Burrows, J.P. (2008) Towards Validation of SCHIAMACHY Lunar Occultation NO2 Vertical Profiles. Advances in Space Research, 41, 1921-1932. http://dx.doi.org/10.1016/j.asr.2007.06.055
Quansah, E., Amekudzi, L.K., Preko, K., Aryee, J., Boakye, R.O., Boli, D. and Salifu, M.R. (2014) Empirical models for Estimating Global Solar Radiation over the Ashanti Region of Ghana. Journal of Solar Energy, 2014, 1-6.