Investigation of the Onset, Cessation and Length of the Rainy Season over Ghana
Abstract
This study seeks to investigate the onset, cessation and length of the rainy season using a
simulated rainfall data from the fourth generation Regional Climate Model (RegCM4) and
measured rainfall data from the Ghana Meteorological Agency (GMet) over Ghana from 1998
to 2012. The results from the RegCM4 was compared with those derived from the measured
rainfall data. The results showed that the mean rainfall onset dates for the Forest, Coastal,
Transition and Northern zones of the country, from the RegCM4 was calculated to be 31st
March, 4th April, 13th April and 2nd May respectively. The GMet measured rainfall values
also had the mean rainfall onset dates determined to be 27th March, 27th April, 8th April and
27th April for the Forest, Coastal, Transition and Northern zones. The mean rainfall cessation
dates from the RegCM4 was recorded to be 2nd November for the Forest zone, 29th October
for the Coastal zone, 15th November for the Transition zone and 20th October for the Northern
zone. The mean rainfall cessation dates from the GMet measured rainfall values was also
determined to be 16th November for the Forest zone, 3rd November for the Coastal zone, 24th
November for the Transitional zone and 9th November for the Northern zone. The average
length of the rainy season from the RegCM4 was computed to be about 216 days for the Forest
zone, 209 days for the Coastal zone, 216 days for the Transition zone and 171 days for the
Northern zone. The GMet rainfall measured data also measured similar average lengths of 234
days for the Forest, 191 days for the Coastal zone, 230 days for the Transition zone and 196
days for the Northern zone. These results may have very useful applications for water resource
management and food security in Ghana.
Description
A thesis submitted to the Department of Physics
Kwame Nkrumah University of Science and
Technology in partial fulfillment of the
requirements for the degree
of
Master of philosophy
in
Meteorology and Climate Science, 2014