Spatio-temporal Analysis of Air Temperature over Northwestern Nigeria: A Climate Change Perspective

The study analyzed spatio-temporal variation in air temperature in Northwestern Nigeria from 1971 to 2010 and predicts air temperature to 2030, 2060 and 2090. Daily minimum and maximum air temperature (°C) data were collected from seven synoptic weather stations in the region from the Nigerian Meteorological Agency, Abuja. Air temperature data of 30 years (1970 to 1999) were also extracted from National Center for Atmospheric Research (NCAR) as well as Community Climate System Model (CCSM) projections from 1970 to 1999 and 2000 to 2099. The spatial variation of air temperature was investigated with the aid of isothermal maps, and the standardized anomaly and trend analysis were used to investigate the temporal variation in air temperature. The IPCC’s A1B and A2 SRES scenarios were used to project air temperature to 2030, 2060 and 2090 respectively. The result showed that within a 40-year period (1971-2010), maximum temperature varied spatially from 31.3^oC - 35.9^oC while minimum temperature also varied spatially from 18.4 ^oC - 22.9 ^oC with warm core over Sokoto and Yelwa, and cool core over Zaria and Kaduna respectively. The 1990’s and early 2000’s were generally warmer compared to other decades. There is a generally increasing trend in both minimum and maximum temperature for the stations and the areally averaged region though only the trends of Zaria and Kaduna (minimum temperature) and Kaduna, Yelwa and Sokoto (maximum temperature) are significant at 95% confidence level. Based on the A1B scenario, maximum temperature is projected to rise by 0.06-0.73°C by 2030, 0.08-0.81°C by 2060, and 0.09-0.85°C by 2090 while minimum temperature is projected to rise by 0.10-0.36°C by 2030, 0.13-0.35°C by 2060, and 0.14-0.37°C by 2090. Using the A2 scenario, maximum temperature is projected to rise by 0.06-0.72°C by 2030, 0.08-0.84°C by 2060, and 0.11-1.00°C by 2090 while minimum temperature is projected to rise by 0.10-0.37°C by 2030, 0.13-0.38°C by 2060, and 0.17-0.49°C by 2090. The study concludes that land use/land cover change due to urbanization and desertification are the major drivers of temperature variability in the region.