Development of Satellite Data- based Rainfall Intensity-Duration - Frequency Curves for Nigeria

Abstract

The paucity of spatially representative sub-daily rainfall data in Nigeria has caused difficulty in the determination of design rainfall necessary for event-based flood modelling. Previous work on the development of Intensity-Duration-Frequency (IDF) curves for Nigeria was done in the 1980s based on historical rainfall data between 1948-1978 at 35 locations in the country (referred to as Federal Ministry of Works-IDF: FMW-IDF); however, extensive application of these IDF curves has been hampered by the vagaries of climate change. Taking advantage of current technological advancements in remote sensing for rainfall estimation, the Tropical Rainfall Measuring Mission (TRMM) Satellite-based estimates was selected amongst four other rainfall products for developing the updated IDF curves. Results indicate that the TRMM product can successfully be applied to develop more spatially representative IDF curves for Nigeria. This work hereby provides 72 locations nationwide with relevant parameters to readily compute rainfall intensity values for the 2yr, 5yr, 10yr, 25yr, 50yr, and 100yr return periods, this carries overarching implications for urban flood design and management in the Country.