Spatiotemporal drought assessment using vegetation health index and standardized precipitation index over Sudano-Sahelian region of Nigeria

ABSTRACT

Drought events were assessed using remote sensing index (Vegetation Health Index, VHI) and meteorological index (12-month Standardized Precipitation Index, SPI-12) over the Sudano-Sahelian Region of Nigeria (SSRN) between 2000 and 2010. Rainfall data of the SSRN were acquired from nine stations of the Nigerian Meteorological Agency (NIMET). Monthly Vegetation Index (MOD13A3) and 8-day Land Surface Temperature (MOD11A2) of the Moderate-Resolution Imaging Spectroradiometer (MODIS) were retrieved from the NASA’s Land Data Product and Services Center (LPDAAC) website. The result from VHI evaluation revealed that about 121.926 km² and 36.063 km² of the region experienced extreme drought in the years 2003 and 2010, respectively, while SPI-12 detected no extreme drought condition during the same period. Both indices detected severe, moderate, and mild droughts (mild drought dominated the SPI-12 results) occurrences. The total area of the region under the influence of drought events from lowest to highest spanned from 233,259.276 km² (in 2007) to 279,189.364 km² (in 2002) and 2704.82 km² (in 2010) to 236,082.70 km² (in 2008) for VHI and SPI, respectively. Results from this study revealed that the VHI gave a better representation of drought severity with continuous/consistent spatial values compared to the SPI.

KEYWORDS:

• Nigeria Sudano-Sahelian region
• drought
• severity
• Standardized Precipitation Index (SPI)
• Vegetation Health Index (VHI)

Disclosure statement

No known conflicts of interest