(iv)From 1995 to 1997, a short wet period marks the Moroccan pluviometry, with a spectacular increase of pluviometry (the regional index reaches +1.37 in 1996, one of the highest values of the first three decades of this series). A number of techniques have been developed for the variability and trend analysis of the rainfall time series. A period qualified as wet is visible on the matrix during 1970–1979. (i)The analysis of the decade 1982–1991 (map shown in Figure 3(a)) shows the predominance of drought conditions in nineteen stations which record more than 50% dry and very dry years and only 7 which correspond to wet and wetter conditions for a little over a half of the duration of the period studied. An annual data precipitation (cumulative rainfall over a calendar year) hierarchy in terms of limit values (Q1, Q2, Median, Q3, and Q4) is done for all stations and for the entire series (Table 1). Abstract-This study investigates rainfall and temperature variabilities in Nigeria using observations of air temperature (C) and rainfall (mm) from 25 synoptic stations from 1971o -2000 (30years). A comparative study with the SPI (Standard Precipitation Index) method for detecting climate drought was conducted in 2015 [41]. The minimum, maximum and mean temperatures have increased significantly for most of the stations. Rainy and very rainy years only account for 22.90%. The evolution of precipitation accumulations of extreme years (1982–2011). Thus, 2013 is one of the warmest years recorded in Tunisia since 1950 [23]. Rainfall variability is expressed by the coefficient of variation (CV). This investigation is based on the calculation of the reduced centered index and the chronological graphical method of processing information (MGCTI) of “Bertin matrix” type. Dry years reach 50% only at three stations (Marrakech, Sefrou, and Sfax). Successive stages with the same trends exceed no more than three years (1987–1989 and 2000–2003 for negative indices and 1995–1997 for positive indices). This is an open access article distributed under the, Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. The “RI” is calculated as follows: where is year value, is the series average, and is standard deviation. Face the future,”, M. H. I. Dore, “Climate change and changes in global precipitation patterns: what do we know?”, L. V. Alexander, X. Zhang, T. C. Peterson et al., “Global observed changes in daily climate extremes of temperature and precipitation,”, M. New, M. Todd, M. Hulme, and P. Jones, “Precipitation measurements and trends in the twentieth century,”, J. H. Christensen, B. Hewitson, A. Busuioc et al., “Regional climate projections,” in, S. Planton, M. Déqué, H. Douville, and B. Spagnoli, “Impact du réchauffement climatique sur le cycle hydrologique,”, F. Giorgi and P. Lionello, “Climate change projections for the Mediterranean region,”, Blue Plan, Environment and development in Mediterranean, Climate change in the Mediterranean, no. Rainfall in Nigeria is subjected to wide variability both in time and space. 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. Thus, south coast regions of western Mediterranean basin have been subjected, in the last years, to strong climate disturbances (these facts are not concordant with the results of climate patterns already cited for precipitations). The MGCTI is developed to facilitate the interpretation of the statistical results for the Mediterranean rainfall analysis, due to the high variability affecting this parameter. Giorgi and Lionello [11] estimate that significant Mediterranean rainfall decline is expected in connection with intensification of the anticyclonic circulation and a northward shift of the string of cyclonic depression areas. An increasing trend of annual maximum temperature was … The higher variability observed in the Indus basin varies from 12 to 87.1%, with a mean value … The regional index is positive for a period of 8 years. Important for planning and management of water resource intervention Tunisia ), and Tunisia ) are not with! Software, a second procedure is conducted ’ s population is dependent on rain-fed, agriculture... Sahelian climatic stations in three countries of central Maghreb ( Morocco, Algeria, and Tunisia ) are primarily. The Mediterranean reaches, during this final year, one of the series provide evidence change... Evident in this period to which rainfall amounts vary across an area or through time that. 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