A Markov Chain Model for Wet and Dry Spell Probabilities at Yola, Adamawa State

Abstract

The theoretical probabilities of wet and dry spells were derived from Markov Chain Model using the threshold level of 0.25mm per day for a period of 20 years to predict the length of dry spell and wet spell during the rainy season (April to September) at Gyawana meteorological station in Yola, North Easter Nigeria. The equilibrium probabilities for the station over the 20-year period are π=(0.76,0.24). This implies that the probability of dry day occurrence regardless of the weather conditions of the previous days is 0.76. The mean dry and wet duration for the station were found to be 5.52 and 1.72 days respectively. The mean weather cycle was 7.44. This information can be used to select the best planting date by avoiding the period of high risk of long dry period near the beginning of the rainy season always experienced in northern Nigeria.