Analytical Study of Land-Sea Breeze Dynamics and Their Influence on Coastal Rainfall Patterns in Ondo State

Land-sea breeze circulations represent a critical mesoscale meteorological mechanism governing coastal rainfall distribution and diurnal precipitation patterns in Nigeria's South West coastal zone. This study analytically examines land-sea breeze dynamics along the Ondo State coastline and their influence on coastal and near-coastal rainfall patterns using a combination of observational and reanalysis data. Hourly surface wind observations from Akure Airport NiMet station and ERA5 10-metre wind fields were analyzed to characterize the land and sea breeze cycles across seasons. The convergence zones associated with the sea breeze front were identified using ERA5 moisture flux divergence fields and cross-validated with IMERG 30-minute rainfall composites during 2019 to 2022. Diurnal rainfall cycle analysis from automatic gauge stations in Ilaje and Okitipupa LGAs reveals a pronounced late afternoon rainfall maximum (15:00 to 18:00) attributable to sea breeze convergence, accounting for 38 percent of total daily rainfall at coastal stations. The inland penetration of the sea breeze front averages 45 kilometres during the wet season, generating a rainfall enhancement zone extending from the coastline to areas north of Ore. Seasonal modulation of the sea breeze intensity by the ambient monsoon flow is documented, with the strongest sea breeze signatures occurring during the inter-monsoon transition months of March and October. The study provides the first systematic documentation of land-sea breeze rainfall dynamics for Ondo State. Keywords: land-sea breeze, coastal rainfall, Ondo State, diurnal cycle, mesoscale circulation.