A Comparison of the Accuracy of Multi-satellite Precipitation Estimation and Ground Meteorological Records Over Southwestern Nigeria

Abstract

Multi-satellite rainfall observations are compared with ground-based meteorological stations data in this study. Both ground and satellite meteorological datasets were analysed and synchronized in this study. Satellite rainfall datasets used are Tropical Rainfall Measuring Mission (TRMM), Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) and African Rainfall Estimation (RFE 2.0), which were obtained from the archives of the NOAA Climate Prediction Centre. The ground meteorological data were obtained from the Nigerian Meteorological Agency (NIMET) Lagos office in Oshodi, for selected stations in Southwest of Nigeria, for the period 1998–2016. Descriptive and inferential analyses were used to analyse the dataset. Spatial and temporal trends analyses were carried out to compare rainfall estimates from satellite and ground stations. Generally, correlation results show that the relationship between satellite datasets and ground observation (NIMET) appears remarkably high in all stations with R2> 0.70. This relationship is greatly strong between TRMM and NIMET in Abeokuta, Akure, and Osogbo with R2 = 0.99, 0.98 and 0.98, respectively. CHIRPS also show high correlation with NIMET in these three stations with R2> 0.90, but RFE-NIMET relationship appears much more in Osogbo with R2 > 0.90. It is also obvious that TRMM and CHIRPS have a very high relationship in almost all locations with R2> 0.87. The major finding from this study is that though in situ meteorological data may be used for local studies of small areas, satellite rainfall estimates may also be used to augment such data, over a larger area. Besides, satellite rainfall estimates are more useful for areas with larger spatial and temporal coverage.