# Monthly Precipitation over Northern Middle Atlas, Eastern Morocco: Homogenization and Trends
## 5 Conclusions  
Our work aimed to study the rainfall trends in the northern Middle Atlas. This is an important area for precipitation climatology and trend analysis; given its potential in terms of surface and underground water resources, this territory is considered a water tower in the country. The first problem we faced was the temporal heterogeneity of the data and the large number of gaps in the series collected. The research problem therefore became the gap-filling, homogenization and trend analysis of the monthly data at the level of the study area. Indeed, a data quality control and homogenization process, to improve the reliability of monthly rainfall records, was applied initially. Secondly, we analyzed trends in monthly series over the period from 1970 to 2019.  
The results obtained show an increase in the quality of the final data, and a good robustness of the chosen Climatol tool for filling gaps and for the regionalization of the data. This step was validated by our knowledge of the climatic characteristics of the terrain. The correlations between stations' monthly precipitation, using the adjusted data, are relatively high (>0.6) for stations located approximately 25 km apart. The correlation coefficient decreases progressively with the distance, reaching a low value of 0.22 in the stations located at a distance of about 100 km. This is not surprising, given the strong variations in both the geographical location of each station in the topographic context and the exposure of the slopes to moist air masses. Orographic discontinuity can give opposite precipitation regimes.  
The RMSE values oscillate between 0.5 and 38.7 mm, with an average of 8.5 mm for all the series studied; the values of the (SNHT) oscillate between 2.5 and 26.6, with an average of 6.28. These low values indicate the reliability and good quality of the data.  
Rainfall trends generally show drier conditions for the months of January, February, March, April, May, June and December. These trends are significantly stronger in the southern and eastern parts of the study area, and only during the month of April, the wettest month. It appears that the month of July is seen as a transformation point towards positive trends. Indeed, 71% of the series have a tendency towards the increase of precipitation, although only five (or 1/3) of them have statistically significant increases. From August to November, generalized positive trends were observed. The percentage of series with a positive and significant trend varies between 55 and 77%. These results show a probable transformation of a winter and spring rainfall regime towards an autumn regime throughout the northern Middle Atlas. This change can disrupt an entire agricultural system that depends on water inputs from the Middle Atlas for irrigation.  
Conceptualization, R.A.; methodology, R.A. and M.H.; software, R.A., R.K. and H.A.; formal analysis, R.A.; validation, R.A., M.H. and N.Y.K.; investigation, R.A. and R.K.; data curation, R.A. and H.A.; writing--original draft preparation, R.A. and N.Y.K.; writing--review and editing, R.A., N.Y.K. and M.H.; visualization, K.O. and B.E.K.; supervision, N.Y.K., M.H., K.O. and B.E.K. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.