## 2 Materials and Methods
### Observed Climate Data Sources and Station Selection  
The data used in this study are monthly rainfall amounts. They were collected from the National Meteorological Services, the Moulouya River Basin Agency (ABHM), and the Water, Forestry and Desertification Control Department (EFLCD) at 35 stations located in or around the Moulouya basin (Figure 1 and Table 1). The choice of data sets is based on quality, reliability, geographical location, and the percentage of gaps in their chronicles. Thus, to properly detect rainfall variability over time, the duration of the data records is also of primary importance, and our series oscillated between 1970 and 2019.  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Name** & **ID** & **Longitude** & **Latitude** & **Elevation** \\ \hline Bab Azhar & S1 & \(-\)4.265918 & 34.046246 & 788 \\ \hline Bab Bouidir & S2 & \(-\)4.125435 & 34.068080 & 1543 \\ \hline Bab Louta & S3 & \(-\)4.331743 & 34.015481 & 575 \\ \hline Bechine & S4 & \(-\)3.931068 & 34.084582 & 970 \\ \hline Belfarah & S5 & \(-\)3.705054 & 34.112617 & 512 \\ \hline Beni Bouiloul & S6 & \(-\)3.979200 & 33.562500 & 1882 \\ \hline Berkine & S7 & \(-\)3.847212 & 33.766181 & 1287 \\ \hline Guercif & S8 & \(-\)3.357308 & 34.219526 & 362 \\ \hline Maghraoua & S9 & \(-\)4.049149 & 33.934194 & 1140 \\ \hline Missouri & S10 & \(-\)3.999194 & 33.045993 & 891 \\ \hline Mrija & S11 & \(-\)3.276919 & 33.995082 & 667 \\ \hline Outat El Haj & S12 & \(-\)3.701842 & 33.332709 & 763 \\ \hline Ras Laksar & S13 & \(-\)3.750186 & 33.961651 & 726 \\ \hline Saka & S14 & \(-\)3.061494 & 34.539729 & 240 \\ \hline Taddert & S15 & \(-\)3.593560 & 34.216035 & 445 \\ \hline Tahla & S16 & \(-\)4.426335 & 34.047740 & 571 \\ \hline Tamjilt & S17 & \(-\)4.015090 & 33.643434 & 1645 \\ \hline Tandit & S18 & \(-\)3.622948 & 33.663278 & 667 \\ \hline Taza & S19 & \(-\)4.009750 & 34.219546 & 522 \\ \hline Tazzeka & S20 & \(-\)4.183007 & 34.089941 & 1971 \\ \hline Zerda & S21 & \(-\)4.375925 & 33.973901 & 841 \\ \hline Rechida & S22 & \(-\)3.226150 & 33.873550 & 1080 \\ \hline Aknoul & S23 & \(-\)3.841523 & 34.649155 & 1000 \\ \hline Ansegmir & S24 & \(-\)4.927237 & 32.577055 & 1400 \\ \hline Khenifra & S25 & \(-\)5.665032 & 32.943861 & 836 \\ \hline Midelt & S26 & \(-\)4.745622 & 32.641576 & 1497 \\ \hline Taourirt & S27 & \(-\)2.876744 & 34.415103 & 358 \\ \hline Zaida & S28 & \(-\)4.961640 & 32.809918 & 1457 \\ \hline Tabouazant & S29 & \(-\)5.066797 & 32.552164 & 1645 \\ \hline Aguelman Sidi Ali & S30 & \(-\)4.994316 & 33.079951 & 2089 \\ \hline Ait Aissa & S31 & \(-\)5.068743 & 33.164349 & 1905 \\ \hline Dar El Hamra & S32 & \(-\)4.371116 & 33.695517 & 1142 \\ \hline \end{tabular}
\end{table}
Table 1: Geographical locations of stations. Code of the coordinate system used is EPSG:26191.  
Unfortunately, the majority of measurement stations in the basin are distributed along the Moulouya wadi or on its main tributaries. Indeed, the eastern side of the basin remains poorly covered in terms of stations recording climatic data. Furthermore, most of these recording stations are located at low altitudes, which can limit the results of our work.  
As in many regions of the world, some of our series are not complete and have gaps that need to be filled. For this purpose, and in order to test the quality of the data, we opted for the Climatol tool (version 3.1.1) [[https://www.climatol.eu/](https://www.climatol.eu/)]([https://www.climatol.eu/](https://www.climatol.eu/)), accessed on 15 December 2022, which is recommended by several climate researchers [54; 55; 56; 57]. The stations from which data were collected are summarized in the table below.