LANDUSE/LANDCOVER CHANGES AND ITS IMPACT ON URBAN NEAR-SURFACE WINDS IN OWERRI, NIGERIA

Ifeanyi G. Ukwe, Polycarp C. Nlem, Ikpong S. Umo, P. E. N. Okoroafor

ABSTRACT

This study examined the modification of the near-surface winds by urbanization process induced by changes in the landuse/landcover patterns. Results from the series of statistical analysis show a significant decrease in near-surface wind speeds in Owerri, southeast Nigeria during the period of rapid urban growth. The decline in wind speeds is found to be much stronger in the city than in the nearby rural area. The dominant wind class frequency of the city declined from 3.1 – 4.0 m/s to 2.1 – 3.0 m/s within the 30-year study period. The results are related to past studies of the changes in the landuse/landcover patterns of the city, which showed an increase in built-up surfaces and a decrease in vegetated surfaces within the study period. Increased surface roughness induced by changing urban landuse/landcover patterns is suggested as the probable cause for the declining wind speeds in the city.