Establishing Climatic Change on Rainfall Trend, Variation and Change Point Pattern in Benin City, Nigeria

Masi G. Sam

Department of Civil and Environmental Engineering, University of Port Harcourt, Choba, Rivers State, Nigeria.

Ify L. Nwaogazie *

Department of Civil and Environmental Engineering, University of Port Harcourt, Choba, Rivers State, Nigeria.

Chiedozie Ikebude

Department of Civil and Environmental Engineering, University of Port Harcourt, Choba, Rivers State, Nigeria.

*Author to whom correspondence should be addressed.


Abstract

This study examined the effect of changing climate for thirty-six years (1982-2017) on 24-hourly annual maximum time series (AMS) rainfall data for Benin City. The results show the existence of a trend, variation in magnitude, and change point dates. Trend analysis was performed using Mann-Kendall (MK) test and Sen’s slope estimator (SSE) applied to obtain the trend magnitude. A statistically significant trend was found for Benin City at a 5% level of significance. The MK |Z| statistic varied from 2.0710 to 2.1550 for IMD and 2.0844 to 2.0995 for MCIMD downscaling models, which were both greater than the critical Z-value of 1.96. The SSE gave the magnitude of the trend variation rate due to climate change at 24-hour duration as 1.008 mm/year (10.08 mm/decade) and 1.1376 mm/year (11.376 mm/decade) for the IMD and MCIMD models, respectively. Also, the trend change point analysis was conducted using the distribution-free cumulative sum test (CUSUM) and the sequential Mann-Kendall test (SQMK) which has rainfall pattern definite change point date for Benin City as 2005 from where continued a positive trend which intensified through the year 2015. Thus, proving the existence of increasing changing climatic condition for the study area.

Keywords: Rainfall data, 24-hourly AMS, statistical tests, trend analysis, change point, changing climate


How to Cite

Sam, Masi G., Ify L. Nwaogazie, and Chiedozie Ikebude. 2023. “Establishing Climatic Change on Rainfall Trend, Variation and Change Point Pattern in Benin City, Nigeria”. International Journal of Environment and Climate Change 13 (5):202-12. https://doi.org/10.9734/ijecc/2023/v13i51761.

Downloads

Download data is not yet available.