Determination of the bioclimatic aridity of seven localities in the province of Tillaberi (South Western part of Niger) and their distribution into bioclimatic zones.

摘要

A study aimed at determining the bioclimatic aridity gradient of seven localities in the Province of Tillaberi (south-western part of Niger) was carried out to distribute these localities into bioclimatic zones. A set of climatic data spreading over thirty years (1970-1999), coupled with biophysical information on this region was used. Result showed that two distinct bioclimatic zones were identified with an intermediary one in-between. The bioclimatic zones are: a semi-arid zone with an aridity degree ranging from 0.21 to 0.19, and comprising the localities of Say, Kollo, and Niamey; an arid zone with an aridity index of 0.17 to 0.15, and containing the localities of Tillaberi, Ouallam, and Filingue. With an aridity index of 0.17, Tera was considered as an intermediary zone. This study provides an insight into the degree of climatic vulnerability of these localities taken individually and collectively..