Satellite Remote Sensing of Land Use Changes in and around San José, Costa Rica

Using AVHRR imagery, the effects of urbanization on surface microclimate during a 7-year period in San José, Costa Rica and its surroundings are expressed as changes in fractional vegetation cover, scaled surface temperature, surface wetness, and surface evapotranspiration. Scatterplots of fractional vegetation cover versus scaled surface temperature depict elongated clusters along which pixels undergoing urbanization migrate toward lower vegetation cover, higher surface temperature, less evapotranspiration, and generally dryer surfaces. This urbanization occurred largely in response to pasture and low-density urban areas changing to high-density urban areas. The evolution in surface microclimate accompanying these changes differs considerably for the various types of urban surfaces, but ultimately the pixels become virtually indistinguishable from one another as urbanization becomes advanced. On the other hand deforestation, which occurred as trees were replaced by crops, did not result in large changes in surface temperature and wetness and may have produced increases with time in evapotranspiration.