An Assessment of the Rainfall and Temperature Variations in Parts of Northern Nigeria

Abstract

The aim of the study is the assessment of rainfall and temperature variations in parts of Northern Nigeria. To achieve the aim, the study set out the following objectives (i) to determine variations in rainfall characteristics in terms of number of rain days, extreme rainfall amounts, variability and ranges; (ii) to determine variations in maximum, minimum and mean temperature patterns and using the time series to determine any trend in the change, (upward or downward) (iii) to predict the values for the periods: 2007-2030, which was also subjected to the time series analysis; (iv) to determine the relationship between rainfall and temperature, and (v) to account for the causes of temperature and rainfall variability in the study area. The data for the study which were collected from the Nigerian Meteorological Agency for eleven (11) stations in parts of Northern Nigeria for a period of thirty six (36) years include, those of rainfall amounts, number of rain days, maximum temperature, and minimum temperature. Simple statistical measures of mean, median, maximum, minimum, standard deviation, variance, skewness, kurtosis and coefficient of variability were used for discerning the patterns and distribution of the climatic elements considered in the study. Time series analysis were carried out to determine the trends and predict future values of the variables. The results achieved indicate that: the region could be divided into two periods on the basis of years with lower temperatures and rainfall (1970s and 1980s) and periods with higher temperatures and rainfall (1990s and 2000s). During the predicted period, 2007-2030, rainfall declines until 2019 and from 2020, rainfall begins to increase until 2030, mean annual number of rain days decrease from 6.5 days per month in 2007 to 5.2 days per month in 2030, mean annual maximum temperature and mean annual minimum temperature continue to increase from 34.50C in 2007 to 36.60C in 2030 and 21.10C in 2007 to 21.50C in 2030 respectively. The southern part of the region has higher rainfall and lower temperatures compared to the northern parts. Temperatures vary very slightly in the region; none of the elements have departed significantly from the normal. There is a general increase in rainfall in the forecast period and a corresponding decrease in the number of rain days. There is also a general increase in mean annual temperature and annual minimum temperature. The work recommends that more of this type of studies be carried out. The result show that no signal has really been detected. We should devote more attention to regional studies of current climatic behaviours in various regions of Nigeria.