An integrated approach to delineation of the eco-climatic zones in Northern Nigeria

Abstract

This study derived eco-climatic indices; a moisture quality index, onset and cessation dates, hydrologic growing season and Aridity Index all for the period (1950-2006), in addition to using National Oceanographic and Atmospheric Administration an Advanced Very High Resolution Radiometer images to derive a Soil Adjusted Vegetation Index map. These derived eco-climatic parameters were integrated using Geographic Information System (GIS) techniques. The overlay was hinged on a theoretical basis which holds that the variations of the Aridity index, cessation dates, length of the hydrologic growing season and vegetation index are directly proportional to eco-climatic zone changes while those for onset and MQI are inversely proportional. The quantitatively derived eco-climatic index and related maps identified five eco-climatic zones; wet, humid, sub-humid, dry sub-humid and semi-arid as against the three classic regional climatic zones. The eco-climatic map further unveils progressive transformation or southwards shifts in the boundaries of the regional climatic zones. Thus, the accurate delineation of the current eco-climatic zones would be essential for providing adequate information needed to achieve food security and sustainability of the physical environment that is fundamental to disaster risk reduction in sub-Saharan Africa.   Key words: Northern Nigeria, climate change, rainfall variability, southwards shifts, eco-climatic zones, food security.