Analysis of Rainfall Dynamics in Conakry, Republic of Guinea

Abstract

Observed rainfall data of the National Meteorological Service of Guinea (NMS) exhibit that synoptic station usually records the largest rainfall amount in Guinea. Only few studies have been done on this rainfall peak observed in Conakry. This work better analyses the atmospheric dynamics leading to rainfall particularity. Using NMS data from 1981 to 2010, the monthly contribution and mean seasonal cycle of each station has been done. These findings of the study show that between July and August (rainfall season peak), the coastline particularly Conakry records the largest amount of rainfall. Using Era Interim data for the common period , we also investigate the rainfall dynamics in the lower level (1000 hPa -850 hPa) from precipitable water, divergence, and moisture flow transport. There is a west and southwest moisture flow transport explained by a strong moisture convergence in the coastal region (Lower-Guinea). Furthermore, values of precipitable water in the same region are found, in agreement with the high moisture flow transport gradient. These incoming flow (west and south-west) undergo a return by blocking's Kakoulima range (foehn effect) and Fouta Djallon massif to initiate convection clouds on the Guinean coast. These processes enhance a convergence of moisture associated with orographic origin convection. This has an important effect by increasing the rainfall amount in Conakry.

Impact of the Sea Surface Temperature in the North‐Eastern Tropical Atlantic on Precipitation Over Senegal

“…More generally, the high relief near the coast contributes to the amplification of precipitation on the windward side of these mountains (Figure 7e), in agreement with Kante et al. (2020).…”

“…A last notable feature of the mean moisture transport over the continent is a distinct weakening of the westerly flow around 10°N-10°W, where the largest mountain in Sierra Leone, the Loma Mansa, rises to almost 2,000 m in height (Figure 7a). More generally, the high relief near the coast contributes to the amplification of precipitation on the windward side of these mountains (Figure 7e), in agreement with Kante et al (2020).…”