Impact of the ITF Relationship and the Onset of Rainfall on Precipitation in the Republic of Guinea

Abstract

Republic of Guinea is one of the West African countries which share form a border with the southern. The rainfall onset in this country is one of the major problems that the farmers face. For it, we determined with more precision, the rainy season onset in eight synoptic stations in Republic of Guinea: Boke, Conakry, Faranah, Kankan, Koundara, Labe, Mamou and NZerekore. Then, we studied the InterTropical Front (ITF) position compared to each station at the onset date. This work better analyses the atmospheric dynamics leading to rainfall particularity. We used the daily rainfall data provided by the National Meteorological Service of Guinea for (1991-2020) years and the dekadal (10-day) ITF position data produced by the National Oceanic and Atmospheric Administration (NOAA) for (1990-2021) years. Using these daily rain of the eight stations and the ITF data, we calculated, the dekadal, monthly and annual rain amount, then we established a relation between the ITF position and the precipitation for each station. Results obtained show that the rainy season begins on May 18th, April 20th, May 4th, May 14th, June 8th, May 12th, April 28th and March 20th in Boké, Conakry, Faranah, Kankan, Koundara, Labe, Mamou and NZerekore regions, respectively. Compared to these dates, the ITF is located 2247.77 km north of Boke, 2136.13 km north of Conakry, 2121.24 km north of Faranah, 2136.13 km north of Kankan, 2236.61 km north of Koundara, 2247.77 km north of Labe, 2236.61 km north of Mamou and 2136.13 km north of NZerekore. The good correlation is obtained between the ITF position and the monthly precipitations for eight regions. This study will allow farmers to know with more precision the rainfall onset in Republic of Guinea.