Analyzing Long-Term Trends in Air Temperature and Precipitation in Bel-Ksiri, Morocco (1980–2024)

The study analyzes climate change in Bel-Ksiri. It provides an understanding of long-term trends (1980-2024) and changes between the last two standard twenty-year climate periods: 1980-2000 and 2001-2020.In this study, we determined the trend of the two variables studied using the Mann-Kendall test and calculated the difference and relative variations in temperature and precipitation. The Kolmogorov-Smirnov test (KS test) was used to compare the two climate periods studied (1980-2000 and 2001-2020). Data analysis was performed using the Python language. Climate trends from 1980 to 2024 reveal a marked warming, particularly in spring and summer, with an increase in daily temperature variations, exacerbating the risk of drought and impacting agriculture, water resources and health. The periods 1980-2000 and 2001-2020 show significant differences, notably an increase in maximum and minimum night-time temperatures, particularly during summer and spring. Analysis of climate indices, such as TX90p and TN90p, shows increases in temperature extremes, with notable rises in hot days and warm nights, underlining gradual warming. The TX30, TX35, TX37 and TX39 indices also show significant increases. Hot spells (WSDI) and cold spells (CSDI) have intensified, although some trends are not statistically significant. These results confirm a marked climate change, with significant impacts on ecosystems and human societies. Precipitation trends show overall rainfall stability, with a slight annual increase (+1.97%) and a notable fall decrease (-6.5%). At Bel-Ksiri, between 1980 and 2024, precipitation indices show small and insignificant variations, with slight increases in PRCPTOT (+1.09 mm/10 years) and RX1day (+0.09 mm/10 years). Analysis of rainy days reveals a slight decrease in days with ≥1 mm (-0.51%) and an increase in days with ≥10 mm (+9.82%), while dry and wet periods have changed slightly, with no statistically significant differences. Keywords: Climate change, global warming, flood risks, water resources, ecosystem .