(a) Homogeneity test for the rainfall dailies from study stations for the period between 2000 and 2013. For instance, high evaporative demand indicated by high aridity index in the drier parts of eastern Kenya implies that rain water is not available for crop use and cannot meet the evaporative demands (Kimani et al., 2005). Then the number of times that a dry-spell of duration longer than or equal to occurs was computed through accumulation. Previous studies have focused on rainfall variability and determining rainfall onset and cessation but have not related the effect of climate variables on maize yields and thus food security in the four counties. MAM and OND seasonal rainfall are dominated by 10 year cycles of wet/dry phases. rainfall variability translation in English-French dictionary. Daily rainfall data were captured into the RAINBOW software [17] for homogeneity testing based on cumulative deviations from the mean to check whether numerical values came from the same population. Box 30677-00100, Nairobi, Kenya. Nicholson (1993) and Hulme [26] attributed the decrease in LRs to the desiccation (drying out) of the March-to-August rains in sub-Saharan Africa (SSA). The main objective of this paper is to assess the rainfall variability and to identify the relationship between paddy production and rainfall, by means of statistical analysis. Kriging and Spline techniques reported more representative values of observed rainfall when compared to the IDW method. Assorted arguments regarding the varied performances of the different interpolation techniques could explain the results of this study. : Spatial and temporal variability of rainfall It is timely to review recent progress in understanding of interactions between rainfall spatial and temporal resolution, variability of catchment properties and their representation in hydrological models. Decadal rainfall trends showed that both long rains (LRs) and average annual rainfall have decreased in the past 13 years in the region. Climate Variability A greater aspect of our weather and climate is its variability. For instance, probabilities of having dry-spells exceeding 15 days are relatively high (63%, 80%, 91%, 93%, and 57% for Machang’a, Kiritiri, Kiambere, Kindaruma, and Embu, resp.) Interpolation under IDW method was generally unsatisfactory when compared to the Spline and Kriging interpolation methods. The variation of rainfall amounts at various locations across a region for a specific time interval. In Embu, the highest positive anomalies (+5.0) were recorded in 2002, 2005, and 2007 during LRs (Figure 4). To optimize agricultural productivity in the region, there was need to quantify rainfall variability at a local and seasonal level as a first step of combating extreme effects of persistent dry-spells/droughts and crop failure. (Area does not vary.). The coefficient of variance (coefficient of variation) statistics were utilized to test the level of mean variations in LR and SR seasonal rainfall, number of rainy days (RD) and rainfall amounts (RA), and -test statistic to evaluate the significance of variation. Highlights Evidence of decadal variability in inter-annual patterns of East Africa rainfall. It has an annual mean temperature ranging from 17.4 to 24.5°C and average annual rainfall of 700 to 900 mm. High probabilities of dry-spells occurring and exceeding the same durations show the high risks and vulnerability that rain-fed smallholder farmers are predisposed to in the study area. Nonetheless, rainfall amount during SRs markedly increased in most study stations, with high amount gains established in the Mbeere stations. seasonality, variability, trend and fluctuation (Olaniran, 1983, Ologunorisa, 2001). In sub-Saharan Africa, the predominant setbacks in analysing hydrometeorological events are occasioned by lacking, inadequate, or inconsistent meteorological data. Mbeere subcounty represents a subhumid climate region, with annual average rainfall of 781 mm while Embu is more humid with annual average rainfall above 1,210 mm (Table 1). It thus emerges that, understanding climatic parameters, rainfall in particular, can aid in developing optimal strattegies of improving the socioeconomic well-being of smallholder farmers. Some of the variability does not appear to be caused systematically and occurs at random times. Rainfall being a prime input and requirement for plant life in rain-fed agriculture, the occurrence of dry-spells has particular relevance to rain-fed agricultural productivity (Belachew, 2002; Rockstrom et al., 2002). Generally, high variability (often attributed to La Nina, El Nino, and Sea Surface Temperatures) could occasion rainfall failures leading to declines in total seasonal rainfall in the study area. As a major concern to food production in Ghana, this study seeks to show the relationship between the production of major crops and rainfall distribution pattern in the Worobong Agroecological Area (WAA) relative to foo… The method used to determine the modes of this variability and the trends of rainfall is the chronological graphic method of information processing (MGCTI) of the “Bertin Matrix” and continuous wavelets transform (CWT). Reason 1998; Goddard and Graham 1999; Cook 2000; Rautenbach and Smith 2001; Nicholson 2003) or monthly, seasonal to annual rainfall totals (e.g. The IPCC climate models predict, for the Maghreb countries, lower rainfall and increased aridity. These results indicate high variability of rainfall received across all AEZs in the study area, further evidenced by massive rainfall anomalies reported earlier by this study. Thus, deficit is likely to prevail throughout the rain seasons as observed in other SSA regions (Li et al., 2006). R. Jaetzold, H. Schmidt, Z. Climate variability is the term to describe variations in the mean state and other characteristics of climate (such as chances or possibility of extreme weather, etc.) In Machang’a, Kiritiri, and Kindaruma, rainfall amounts during LRs were highly variable (CV = 0.41, 0.39, and 0.47, resp.) On the other hand, Kriging technique was identified as the most appropriate geostatistical interpolation techniques that can be used in spatial and temporal rainfall data reconstruction in the region. B. Hornet, and C. A. Shisanya, J. Mugwe, D. Mugendi, M. Mucheru-Muna, D. Odee, and F. Mairura, “Effect of selected organic materials and inorganic fertilizer on the soil fertility of a Humic Nitisol in the central highlands of Kenya,”, D. Raes, P. Willems, and F. Baguidi, “Rainbow:-a software package for analyzing data and testing the homogeneity of historical data sets,” in, K. K. Kumar and T. V. R. Rao, “Dry and wet spellsat Campina Grande-PB,”, J. J. Botha, J. J. Anderson, D. C. Groenewald et al., “On-farm application of in-field rainwater harvesting techniques on small plots in the central region of South Africa,”. , would the following charts be used to illustrate failures, in RA... 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