Exploring climatic variability and drought characteristics in Morocco’s Sais Plateau and Middle Atlas: A statistical and spectral analysis

¹ Laboratory of Geo-Environmental Analysis, Planning and Sustainable Development, Faculty of Letters and Human Sciences, Sidi Mohamed Ben Abdellah University, Fez, Morocco
² Environmental, Ecological and Agro-industrial Engineering Laboratory, Faculty of Sciences and Technics, University of Sultan Moulay Slimane, Beni Mellal, Morocco

^* Corresponding author: zouhir.qadem@usmba.ac.ma

Abstract

Extreme climate change phenomena are a global reality with major repercussions on hydrosystems. Drought is particularly concerning in the southern Mediterranean region, threatening water availability and related behavior. Morocco, located in North Africa and the southern Mediterranean, is highly exposed to climate change and its consequences, particularly drought. This study aims to investigate the impact of climate variability and drought characteristics on the Saïs plateau and the Middle Atlas region, using statistical and spectral indices. By analyzing annual variations in precipitation and using the Standardized Precipitation Index (SPI) and normalized difference water index (NDWI) to elucidate the temporal dynamics of water, this study highlights significant irregularities in precipitation patterns between wet and dry years, offering insight into the severity and occurrence of drought at different altitudes. In addition, the study uses the normalized difference water index (NDWI) to elucidate temporal water dynamics, revealing cyclical patterns of water availability and identifying regions sensitive to hydrological activity or drought. Furthermore, thanks to a correlation analysis between the NDWI and the SPI12 index, the study highlights the complementary relationship between spectral and statistical indices in the assessment of drought phenomena. The results show a significant difference in precipitation between the Middle Atlas and the Sais Plateau, with the Middle Atlas receiving around double the precipitation. From 1980 to 1985, drought was followed by even drier conditions until 1995, with sporadic wet years such as 1995 and 2002. During the 1980–1994 period, a persistent drought was observed until 1995, when precipitation picked up again, with notable records in 2009–2010. Positive NDWI values, with marked peaks between 2010 and 2012, indicate periods of high-water content, while negative values, such as those in 1995, 2003, and 2006, denote periods of low water content or drought.