Journal of Geography and Earth Sciences

A Spatiotemporal Characterization of Historical Drought Using Reanalysis Precipitation: A Useful Tool in Weather Index-Based Insurance
Juddy N. Okpara, Kehinde O. Ogunjobi, Elijah A. Adefisan

Abstract
The study attempts to depict and characterize drought hazards using the reanalysis Standardized Precipitation Index (r-SPI). Also, examined is the potential of r-SPI model-based designed conceptual framework in a weather insurance contract. Due to paucity of station in-situ data, 36 years of reanalysis of precipitation data have been used to investigate the spatiotemporal characteristics of drought and its usefulness to farmers averse to risks. With fixed subjective threshold of -1.50, results revealed 4 to 11 cases of severe drought intensities of varying duration of 2 – 7 months or more. However, with varying objective thresholds of -1.33, -1.35. -1.35 and -1.33 for the Upper Niger, Inland Delta, Middle Niger, and Lower Niger sub-basins respectively, there were 4 to 13 severe drought incidences of varying duration of 2 – 7 months or more identified with the historic drought-induced famine of 1980s well captured. Every 10 years, different parts of the Niger basin experience drought events of different durations and magnitudes; with the same amount of monthly precipitation producing different SPI values and cumulative probabilities, and varying crop yields in different parts of the basin. With a conceptual framework driven by SPI 3-month, 83-88% of the variances in cereal crop yield can be explained.

Full Text: PDF     DOI: 10.15640/jges.v9n2a1