TEMPERATURE AND RAINFALL VARIABILITY STUDIES WITHIN SOUTH-SOUTH REGION OF NIGERIA

Abstract

The annual rainfall and temperature variables from 1978-2017 for the South-South region of Nigeria were retrieved from the records of NiMet in order to ascertain the recent extent of the variation in the climatic conditions of the region. The methods used for the analyses are simple approach, coefficient of variability (CV), anomaly approach, trend evaluation using parametric and non-parametric methods, and the data homogeneity test. The results show that the differences between 1978-1997 and 1998-2017 revealed variability of; -7.0 mm, -0.3^oC, and -0.3^oC for rainfall, maximum and minimum temperatures respectively. The overall CV of the maximum temperature, minimum temperature and annual rainfall is 0.026, 0.036, and 0.145 respectively. From the anomaly results it was unveiled that 21 years recorded higher rainfall whereas 19 years recorded lower rainfall. Moreover, 24 years were warmer than normal, 13 years were less warm than normal while 3 years were having a normal temperature. The Sen’s estimator slope of the annual rainfall recorded a downward trend of -94.0 mm/yr during 1978-1987 decade with a slope of -3. There were upward trends of 90.0 mm/yr with a slope of 1, 30 mm/yr with a slope of 1 and 118.0 mm/yr with a slope of 1 for 1988-1997, 1998-2007, and 2008-2017 decades respectively. While the maximum temperature recorded a downward trend of -0.1℃/yr with a slope of -1 in 1978-1987 decade. It recorded a rising trend of 0.1℃/yr with a slope of 0 in the 1998-2007 decade. The remaining two decades recorded no trend in the maximum temperature with a slope of 1 and 0 respectively. Similarly, the minimum temperature recorded upward trend of 0.1℃/yr with a slope of 0 in 1988-1997 periods, while 1978-1987, 1998-2007, and 2008-2017 decades recorded no trend with a slope of 2, 0, and 1 respectively. This study has again unveiled the fact that there is variation in the climate. Accordingly, there is a conceptual need to keep the general public on alert due to its vicious impacts so as to take the appropriate measures and adaptation opportunities for its mitigation.