TITLE:
Characterization of Precipitation Indices in the Republic of Guinea Using In-Situ Data
AUTHORS:
Moussa Mamady Traore, Dahirou Wane, Ibrahima Camara, Tamba Nicolas Millimono, Ibrahima Kalil Kanté, Mamadou Bailo Barry, Moussa Diakhaté, Abdou Lahat Dieng, Saidou Moustapha Sall
KEYWORDS:
Precipitation, Climate Indices, In-Situ Data, Climate Extremes, Temporal Trends
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.15 No.4,
October
29,
2025
ABSTRACT: The Republic of Guinea experiences a tropical climate marked by a dry season influenced by the Harmattan winds and a rainy season driven by the West African monsoon, with a mean annual rainfall of approximately 1835 mm. This study examines precipitation trends using meteorological data from twelve synoptic stations over the period 1983-2013. Twelve precipitation indices, classified into four categories: hydrological, agro-hydrological, agronomic, and extreme precipitation indices, were analyzed to assess spatiotemporal variability. Trends were evaluated using the Mann-Kendall test at significance levels of 90%. Results reveal a pronounced north-south gradient in rainfall distribution, with the south receiving more abundant and intense precipitation. Agro-hydrological indices indicate that the rainy season begins around mid-January in southern regions, while the monsoon onset occurs nationwide by May 1st. Seven-day wet spells are frequent in the south, whereas dry spells predominate in northern areas. Conakry exhibits a high frequency of extreme wet events, in contrast to northern regions, which are more susceptible to severe dry conditions. Trend analysis shows a significant increase in wet-day indices, while indices related to dry days and extreme rainfall events display a statistically significant decrease.