TITLE:
Urban Climate Analysis with Remote Sensing and Climate Observations: A Case of Morogoro Municipality in Tanzania
AUTHORS:
Siwa Ernest, Augustino R. Nduganda, Japhet J. Kashaigili
KEYWORDS:
Radiant Temperature, Impervious Surfaces, Urban Heat Island, Random Forest Algorithm, Mann-Kendall Test
JOURNAL NAME:
Advances in Remote Sensing,
Vol.6 No.2,
June
15,
2017
ABSTRACT: Rapid urbanization is threatening sustainable development of urban areas in Tanzania. Among the risks of rapid urbanization are Urban Heat Island (UHI) effect and climate change. While this has been noted, it is not known to what extent these risks are being realized in fast growing urban areas like Morogoro and other areas of similar geographic and climatic conditions. Therefore a study was conducted to assess the influence of urbanization on UHI and climate in Morogoro Municipality using remote sensing and climate data. Landsat imageries acquired in 1990, 2000 and 2015 were used to assess the change of impervious surface for the year 1990 to 2015 using a Classification and Regression Tree (CART). Radiant surface temperature and normalized difference vegetation index (NDVI) were derived from thermal band and reflectance bands respectively. Mann-Kendall test was used to analyze climate data for trends. Results revealed an increase of impervious surface (built up areas) from 9 km2 in 1990 to 48 km2 in 2000 and 82 km2 in 2015; which is associated with UHI. UHI was not apparent in 1990, but was apparent in 2000 and 2015 with the temperature rise of 1.08°C and 1.22°C respectively. A linear relationship between radiant surface temperature (TB ) and percent Impervious Surface (ISA); and between TB and NDVI it revealed that NDVI is better indicator of variations in TB dynamics than percent ISA. Mann-Kendall test indicated a significant increasing trend in mean annual maximum temperature. The results imply that increasing ISA coupled with vegetation degradation has contributed to temperature rise and change. Consequently, Morogoro Municipality residents are likely to suffer heat stress due to rapid urbanization. It is recommended that education on the use of reflective surfaces should be given to the residents; and an effective master plan that protects vegetation should be in place.