The statements, opinions and data contained in the journal, © 1996-2020 MDPI (Basel, Switzerland) unless otherwise stated. The “RI” is calculated as follows: where is year value, is the series average, and is standard deviation. For all Moroccan stations studied, the proportion of dry and very dry years reaches almost 56%, while rainy and very rainy years account for a little more than a quarter, with 24%. According to the results of various prediction of climatic models, both global and regional, a rise in temperatures and decrease in rainfall are expected [15–17]. The regional index is positive for a period of 8 years. Despite this feature, and considering temperature rise, an increase in rainfall is likely to occur in certain region of the world favorable to such climate evolution. A first stage of strong variability in 1970–1986. Research in the group aims to provide a more solid understanding of climate processes in key rainfall regions such as southern Africa, central Africa/Congo Basin, East Africa and the Sahel. dry, between the first and the second quintile; normal with trends towards drought, between the second quantile and the third quintile; rainy, between the third and the fourth quintile; From 1980 to 1987, an uninterrupted succession of years with negative regional indices can be noted. Recent analysis of the rainfall base for the eastern transect (Malou R. 2002; Malou R. [...] 2004) has allowed establishment [...] of future bases for rainfall variability in the east of the [...] country (Kolda and Bakel weather [...] stations) where models predict greatest change. The dry and very dry classes represent just over 39% of years. This article aims to analyze the precipitation trend for more than forty years of measurements on a wide northern strip in central Maghreb (Morocco, Algeria, and Tunisia). 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).  find no statistical significancy in the cumulative and extreme rainfall trends (summer and winter events) in 9 stations of this last country. The regional index is positive for almost 53% of years and negative for the remaining 47%. A & Ogunjobi K. O. This map confirms a return of more favorable conditions throughout the entire territory, as the decrease of dry and very dry years is common at 29% of the stations (of which 14% show stabilisation of this category of humidity for the two decades). Asfaw et al. A sequence of three rainy years (1971–1973) can be noted at the beginning of the series, while, for the rest of the period, trend inversions (dry year, rainy year) are for two successive years at most. Climate change is today acknowledged by a large part of the scientific community. By Akinsanola A. The beginning of the period tends less to this oscillation (a sequence of three rainy years is noticeable from 1971 to 1973). "Rainfall Variability and Trend Analysis of Rainfall in West Africa (Senegal, Mauritania, Burkina Faso)." It is shown that the convective scale variability is strongly influencing the spatial pattern of rainfields at larger time and spatial scales. The sum of numbers of all stations for each year is centered and reduced, thus getting a regional index (RI) varying from +1.80 for a very wet year to −1.80 for a very dry year. Rainfall in Nigeria is subjected to wide variability both in time and space. 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). Author to whom correspondence should be addressed. 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