AN APPRAISAL OF THE ECMWF REANALYSIS5 (ERA5) MODEL IN ESTIMATING AND MONITORING ATMOSPHERIC WATER VAPOUR VARIABILITY OVER NIGERIA

This study research the performance of ERA5 reanalysis model in estimating and monitoring variability atmospheric water vapour content over Nigeria. The is a fifth-generation recently released by European Centre for Medium-Range Weather Forecasts (ECMWF). comes with excitingly high spatial temporal resolution when compared to earlier models like ERA-Interim ERA-40. However, previous models, numerous modelling uncertainties arising from data fusion methods observation schemes, which often affects its at different regions Earth. In this study, precipitable (PWV) was validated GNSS PWV permanent stations Nigeria NIGNET period 2012–2013. investigated sub-daily, diurnal, seasonal scales relation KöppenGeiger climate classification using standard statistical metrics (namely, coefficient correlation (r), Root mean square error (RMSE), Reliability index (RI), Mean absolute errors (MAE) bias). r, RI, RMSE, MAE bias values diurnal were computed as, (0.8670, 0.882, 0.979), (3.697 mm, 3.400 7.014 mm), (1.015, 1.019, 1.008), (2.769 2.706 1.939 mm) (0.826 2.033 1.739 respectively. results indicate strongest scale more than 95% agreement. pattern within zones showed good consistency Köppen-Geiger classification. recommended use retrieval historic records near real-time applications.