Analysis of Rainfall Variability in Ghana

2013

English

Understanding the decadal and/or annual variability and distributions of rainfall of a region is important and useful especially for agricultural activities. Rainfall data from 77 stations were analysed to determine the mean annual and interdecadal rainfall variability and distribution in Ghana for the period 1981-2010. The ArcView GISTM (version 3.2) software was the tool used to analyse the temporal variability of the decadal mean rainfall for the periods 1981-1990, 1991-2000 and 2001- 2010. The study shows variation on high and low rainfall distributions in the country. With respect to previous studies, results showed a general decline in mean annual rainfall for the period 1981-2010 with high rainfalls shifting to the South-western corner of the country. However, it could be deduced that mean decadal rainfall amounts in Ghana is on a gradual increase from 1981 to 2010, though the rate at which it is increasing is on a decline, i.e. from 8.6 % in 1991-2000 to 2.6 % in 2001-2010. We recommend that the agro-meteorological sub-department of the GMET studies the inter-annual and/or inter-decadal rainfall variability and distribution in the country and appropriately inform farmers of the same in order to avoid total crop failure. We also recommend that studies on rainfall variability in Ghana be carried out in a continuous manner as and when new rainfall data is available.

Logah, F. Y.; Obuobie, E.; Ofori, D.; Kankam-Yeboah, K.