ANALYSIS OF SPATIAL AND TEMPORAL VARIATION OF URBAN HEAT ISLANDS WITHIN KADUNA METROPOLIS

ABSTRACT

Understanding the spatial variation of urban heat Islands (UHI), will
be helpful in urban micro climate studies. This study the urban heat islands of
Kaduna metropolis, Nigeria. For the present study Landsat ETM+ images of 2001,
2006, 2009 and OLI 2015 was obtained from USGS of the study area. Normalized
Difference Vegetation Index (NDVI) image was developed. The digital number of
thermal infrared band is converted in to spectral radiance using the equation
supplied by the Landsat user’s hand book. The effective at-sensor brightness
temperature is obtained from the spectral radiance using Plank’s inverse
function. The surface emissivity based on NDVI is used to retrieve the final
LST. It was noted that 2006 has the highest maximum value of temperature with
the highest mean value of 0.178 and standard deviation of 0.0903 while 2001 has
the minimum value of NDVI. So also 2001 has the maximum value with highest mean
value of 0.999 and standard deviation of 0.00161 while 2015 has the minimum
value of surface emissivity. The coefficient determinant R2 (0.837) show a
strong positive correlation between mean of surface emissivity with date and
season which shows downward trend in average over the study period. 2015 has
the highest mean value of 39.42 with standard deviation of 1.92 of LST and
coefficient determinant R2 (0.457) show a positive correlation between mean of
LST with date and season, with an upward trend in average LST over the study
period. Lastly, NDVI is found to have negative correlation with LST. The
Coefficient of determination (R2) (0.66) of surface temperature with NDVI and
surface emissivity show a better prediction power of land surface temperature.