TITLE:
Comparative Analysis of Climatic Change Trend and Change-Point Analysis for Long-Term Daily Rainfall Annual Maximum Time Series Data in Four Gauging Stations in Niger Delta
AUTHORS:
Masi G. Sam, Ify L. Nwaogazie, Chiedozie Ikebude, Jonathan O. Irokwe, Diaa W. El Hourani, Ubong J. Inyang, Bright Worlu
KEYWORDS:
Rainfall Time Series Data, Climate Change, Trend Analysis, Variation Rate, Change Point Dates, Non-Parametric Statistical Test
JOURNAL NAME:
Open Journal of Modern Hydrology,
Vol.13 No.4,
October
10,
2023
ABSTRACT: The aim of this study is to establish the prevailing conditions of
changing climatic trends and change point dates in four selected meteorological
stations of Uyo, Benin, Port Harcourt, and Warri in the Niger Delta region of
Nigeria. Using daily or 24-hourly annual maximum series (AMS) data with the
Indian Meteorological Department (IMD) and the modified Chowdury Indian
Meteorological Department (MCIMD) models were adopted to downscale the time
series data. Mann-Kendall (MK) trend and Sen’s Slope Estimator (SSE) test
showed a statistically significant trend for Uyo and Benin, while Port Harcourt
and Warri showed mild trends. The Sen’s Slope magnitude and variation rate were
21.6, 10.8, 6.00 and 4.4 mm/decade, respectively. The trend change-point
analysis showed the initial rainfall change-point dates as 2002, 2005, 1988,
and 2000 for Uyo, Benin, Port Harcourt, and Warri, respectively. These prove
positive changing climatic conditions for rainfall in the study area. Erosion
and flood control facilities analysis and design in the Niger Delta will
require the application of Non-stationary IDF modelling.