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Abstract Extreme climate events often have a significant and direct impact on social, economic, and environmental systems. This study is an attempt to characterize the current trends and future projections of extreme climatic indices in an arid region of Morocco on both an annual and a seasonal scale using 12 precipitation and temperature-based indices. The Mann–Kendall test was used to assess the trends, and the inverse distance weighted interpolation method was employed to analyze the spatial distribution of extreme precipitation indices. The results showed that the most extreme climate indices are spatially distributed with a clear gradient from the mountainous area toward the plains. Furthermore, the analysis indicates nonsignificant downward trends in the number of days with a rainfall amount greater than 10 or 20 mm. However, a significant negative trend in the consecutive dry days was observed at the Iloujdane and Sidi Bouathmane stations. The temperature indices have recorded statistically significant upward trends at all the stations. Finally, based on the RCP4.5 and RCP8.5 scenarios, future climate change simulations show, respectively, annual precipitation decreases of 23 and 34% and temperature increases of 1.9 and 2.8 °C, which could imply substantial losses of cereal yield in the rainfed agriculture.

In spite of color being one of the physicochemical parameters most commonly used to characterize a rock, very limited studies have studied the correlation between the nature, chemical composition, and color of a rock. This study presents a new approach for quantitatively assessing the relationship between these three parameters for specific rocks (example of igneous and sedimentary rocks) collected from the High Atlas of Morocco. A spectrophotometer was used to measure the color of samples, and the measurements were expressed in CIE L*a*b* color system units then converted to Hex color codes. Whereas, the chemical composition of samples was carried out by X-ray fluorescence.The most abundant oxides in magmatic rock samples are SiO 2 , Al 2 O 3 , Fe 2 O 3 , MgO, and CaO, while K 2 O, Na 2 O, TiO 2 , and P 2 O 5 are generally found in trace concentrations. Two categories of clays were studied, non-calcareous raw materials without carbonate contents (<4% CaO) and calcareous clays or marls (CaO > 10%). Phosphate samples are rich in phosphorus (4.4%-17.5%) and CaO (11.2%-42.7%) with relatively low contents of SiO 2 (28.5%-52.2%), Al 2 O 3 (3.1%-17.5%), and Fe 2 O 3 (1.1%-6.6%). Results show that the change in the content of these elements from one rock type to another may be indicative of rocks with particular characteristics that do have an impact on color. The main coloration agent of clays was iron, Fe 2+ , and Fe 3+ ions can color clay minerals either red or green or in various shades of orange and brown. However, in marls and phosphates, the high concentration of carbonates inhibits this iron effect by affecting a* (red) and b* (yellow) color parameters, which leads to grayish materials. The same applies to magmatic rocks rich in Fe 2 O 3 and CaO.

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Archeological decorated ceramics from the Saadian tombs and El Badi palace sites (Marrakech, Morocco) have reached an advanced deterioration phase; the glazes have been increasingly weakened due to human and environmental impacts over time. Portable X-ray Fluorescence (pXRF) was performed in situ and on samples selected from these two monuments, in order to define the chemical agents responsible for the color of the studied glazed ceramics and to determine their evolution over time to help find answers and link between degradations and chemical compositions of different type of glazes. The results show that all samples are lead-silica type glazes with 25-59 wt% of PbO and 51 wt% of SiO 2 . The coloring agents used for the original glaze are conventional, copper (Cu 2+ ) for the green color, iron (Fe 3+ ) and manganese (Mn 2+ ) for the yellow and black glaze. Phosphorus (P 2 O 5 ), comes from carbonate mineral phases, is responsible for the blue opalescence of glazes. The study reveals that the ceramic industry has evolved recently in Morocco; elements such as calcium and potassium are currently used in small quantities while lead is increasingly used as flux in the glaze mixture. Iron and copper are still used for black, yellow and green colors, while the use of phosphorus has been replaced by other elements such as cobalt and copper.

Flood frequency analysis could be a tool to help decision-makers to size hydraulic structures. To this end, this article aims to compare two analysis methods to see how rare an extreme hydrometeorological event is, and what could be its return period. This event caused many deadly floods in southwestern Morocco. It was the result of unusual atmospheric conditions, characterized by a very low atmospheric pressure off the Moroccan coast and the passage of the jet stream further south. Assessment of frequency and return period of this extreme event is performed in a High Atlas watershed (the Ghdat Wadi) using historical floods. We took into account, on the one hand, flood peak flows and, on the other hand, flood water volumes. Statistically, both parameters are better adjusted respectively to Gamma and Log Normal distributions. However, the peak flow approach underestimates the return period of long-duration hydrographs that do not have a high peak flow, like the 2014 event. The latter is indeed better evaluated, as a rare event, by taking into account the flood water volumes. Therefore, this parameter should not be omitted in the calculation of flood probabilities for watershed management and the sizing of flood protection infrastructure.