Assessment of rainfall variation and trends in Calabar for the period 1982–2011 Ekpe I. A., Afangideh A. I., Offiong R. A. Dept. of Geo. & Environmental Science, University of Calabar, Nigeria Online published on 11 December, 2013. Abstract The study examines the variation and trend of rainfall in Calabar for the period 1982–2011. Rainfall data for the study were collected from the Nigerian Meteorological Agency (NIMET),Margaret Ekpo International Airport, Calabar. Statistical techniques such as mean, standard deviation, standardized anomaly, coefficient of variation (CV) and Time Series Charts with Trend line analysis(smoothen with 5-years running mean)were used to depict the temporal variation of rainfall in Calabar. Furthermore, spectral analysis was also used to determine the periodicities of rainfall for Calabar using the 30 years (1982–2011) rainfall data. The result shows that the mean annual rainfall for the period of study over Calabar was found to be 2917.72 mm. The study also shows that 2011was the wettest year, while 1983 was revealed to be the most rainfall deficit year. When a 5 year running mean was put through the annual total rainfall series fluctuations involving increasing trend were most prominent in the periods 1986 – 2001 and 2006 – 2011. A fluctuation involving decreasing rainfall trend was only prominent in the period 2001 – 2006. Significant at 95%, the spectral analysis results gives dominant peaks at 3.9 years and 8.1 years, indicating the significant cycles of rainfall for the past 30 years in Calabar. Top Keywords Rainfall Variation and Trend, Spectral Analysis, Time Series Analysis, Rainfall Cycles, Calabar. Top |