Spatial-Temporal Variation and Prediction of Rainfall in Northeastern Nigeria

Abstract

In Northeastern Nigeria seasonal rainfall is critical for the availability of water for domestic use through surface and sub-surface recharge and agricultural production, which is mostly rain fed. Variability in rainfall over the last 60 years is the main cause for crop failure and water scarcity in the region, particularly, due to late onset of rainfall, short dry spells and multi-annual droughts. In this study, we analyze 27 years (1980-2006) of gridded daily rainfall data obtained from a merged dataset by the National Centre for Environmental Prediction and Climate Research Unit reanalysis data (NCEP-CRU) for spatial-temporal variability of monthly amounts and frequency in rainfall and rainfall trends. Temporal variability was assessed using the percentage coefficient of variation and temporal trends in rainfall were assessed using maps of linear regression slopes for the months of May through October. These six months cover the period of the onset and cessation of the wet season throughout the region. Monthly rainfall amount and frequency were then predicted over a 24-month period using the Auto Regressive Integrated Moving Average (ARIMA) Model. The predictions were evaluated using NCEP-CRU data for the same period. Kolmogorov Smirnov test results suggest that despite there are some months during the wet season (May-October) when there is no significant agreement (p < 0.05) between the monthly distribution of the values of the model and the corresponding 24-month NCEP-CRU data, the model did better than simply replicating the long term mean of the data used for the prediction. Overall, the model does well in areas and months

An Analysis of Rainfall Characteristics in Machakos County, Kenya

“…In Malaysia, [3] observed increasing annual totals but with very high monthly variation ranging from -30% to +30%. Episodes of repeatedly delayed rainfall onset, short dry spells and prolonged droughts have been experienced in Nigeria over the last 60 years [4]. In the Horn of Africa, decline in the long rains (March, April and May) in the past 30 years resulting in below normal rainfall have been observed [5].…”

Characteristic temporal variability and trend of annual rainfall series in Port Harcourt Nigeria, a tropical coastal location

“…The SPI values were plotted against the years using Excel 2010 software. Regression analysis has been used in combination with other tools to analyze trends in climatic parameters in Nigeria (Amadi et al, 2014;Afangideh et al, 2010;Bibi et al, 2014) and across the globe (Durlo, 2006;Liu et al, 2006;Turkes et al, 2002;Gil-Alana 2008;Zhihua et al, 2013). The SPI is expressed as by McKee et al (1993):…”

A review of the evaluation of irrigation practice in Nigeria: Past, present and future prospects

“…water resourcess development for irrigation plays a key role in agricultural and economic growth (Mugagga and Nabaasa, 2016). Since agriculture and irrigation are intertwined, especially in a country like Nigeria where there is a wide spatial-temporal variation of rainfall across the country (Akande et al, 2017;Bibi et al, 2014), every plan towards agricultural development must also be extended to irrigation system development. It is on this premise we reviewed the future prospects of irrigation development in Nigeria under the population growth, resources availability, and government policy.…”

“…The climate in Nigeria is characterized by relatively high temperature and variations in the amount of precipitation throughout the year with alternating two seasons (rainy and dry) (Ibe and Nymphas, 2010). The rainy season is generally from April to October and the dry season from November to March, with some degrees of spatial and temporal variations in the amount and distribution of rainfall across the agro-ecological zones (Akande et al, 2017;Bibi et al, 2014). The southern part of the country has the highest average annual rainfall, ranging from 1524 to 2035 mm with duration of eight to nine months.…”