The Fifth-generation PSU/NCAR Mesoscale Model (MM5) is used to characterize the climatic effect of growing urbanization in Metro Manila from 1988 to 1997. Simulations are performed using the same initial and boundary conditions for different land cover data derived from satellite images of Metro Manila to isolate the influence of land cover change on the local atmosphere. It is found that surface temperature and winds are changed mostly in the area converted from rural to urban. The influence of urban growth is not only confined to the modified section where there is a mean temperature rise of 1.0°C. It also affects the original core of the city and areas near the urban-rural boundary, though the difference is not considered statistically significant. The higher surface temperature in the city induces winds from the surrounding water bodies and rural areas toward the urban region. Wind speeds are reduced as they flow over the rough urban surface. When a change in the synoptic conditions is considered together with land cover change, results indicate the important influence of the synoptic circulation on temperature change between 1988 and 1997. Inspite of this, the urban heat island effect associated with land cover change can still be discerned most notably during the daytime.
Manila Observatory
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