Quantification of historical drought conditions over different climatic zones of Nigeria

TL;DR

This study analyzes drought trends across Nigeria's climatic zones using SPI and SPEI indices from 1980 to 2010, revealing increasing drought conditions likely linked to climate change.

Contribution

It provides a comprehensive temporal analysis of drought indices across Nigeria's climatic zones using long-term meteorological data.

Findings

Droughts are more prominent at 6- and 12-month timescales.

SPI and SPEI are better correlated at longer timescales.

There is an increasing trend in drought conditions across Nigeria.

Abstract

The impact of extreme climate such as drought and flooding on agriculture, tourism, migration and peace in Nigeria is immense. There is the need to study the trend and statistics for better planning, preparation and adaptation. In this study, the statistical and temporal variation of climatic indices Standardized Precipitation Index (SPI ) and Standardized Precipitation Evapotranspiration Index (SPEI) were computed for eighteen (18) stations covering four climatic zones (Sahel, Midland, Guinea Savannah and Coastal) of tropical Nigeria. Precipitation, minimum and maximum temperature from 1980 - 2010 obtained from the archives of the Nigerian Meteorological Services were used to compute both the SPI and SPEI indices at 1-, 3- 6- and 12-month timescales. The temporal variation of drought indices showed that droughts were more prominent at 6- and 12-months timescales. SPI and SPEI were found to be better correlated at longer timescales than short time scales. Predominant small, positive and significant trend across the region suggest an increasing trend due to climate change.