The Meteorological and Climatic Mechanisms of Precipitation in the Guercif Basin (Northeastern Morocco): A Spatio-Temporal Analysis (1992-2024)

Abstract

This article analyzes the main aerodynamic mechanisms responsible for precipitation generation in the Guercif basin, a semi-arid region in northeastern Morocco. This region is crucially dependent on large-scale climatic fluctuations, with Atlantic and Mediterranean depressions, supported by atmospheric rivers, constituting the primary sources of precipitation.

The methodology relies on a multi-source approach integrating climatic and hydrological data covering the period 1992-2024. Sources include WorldClim for high-resolution climate data, Climate Engine for interactive climate analysis, and NASA POWER satellite data. The analysis of atmospheric configurations utilizes GFS models and ERA5 reanalysis, while climate teleconnections are evaluated via NOAA indices (NAO, EA, MO).

The results reveal a significant decrease in annual precipitation (-3% per decade, p < 0.05) accompanied by increasing interannual variability. Seasonal analysis identifies autumn and winter as the wettest seasons, with strong negative correlations between climate indices (NAO: r = -0.65 to -0.75; MO : r = -0.45 to -0.55) and winter precipitation.

The study highlights the role of dominant synoptic regimes (zonal, blocking, meridional) and the determining influence of local topography on the modulation of rainfall amounts and spatial distribution. It also underscores the intensification of atmospheric river events and the increasing persistence of blocking configurations as explanatory factors for the observed changes.