Land Use Primer:
How does land use/land cover affect local climate?
Land surface changes can affect local precipitation and temperatures. Vegetation patterns and soil composition can influence cloud formation and precipitation through their impact on evaporation and convection (the rise of air). (de Sherbinin 2002). The effect of land cover on climate depends on the type of land cover that is present in a specific region. For example, barren lands tend to heat more rapidly and can transmit this heat to the lower atmosphere.
A recent study of the United States on summer climate using computer models of NASA and the National Oceanic and Atmospheric Administration (NOAA story on Land Cover/Climate
) , found that land cover changes from grassland to agriculture in part of the Great Plains and the Midwest brought as a result a significant cooling effect. A possible explanation is that farmlands tend to create lower temperatures due to increases in evaporation. In the same study, a warming effect associated to land use change from forest to croplands was found along the Atlantic cost of the United States. Within the climate system, forests are more efficient in transpiration processes where the evaporation of plants during photosynthesis and helps to cool the air. For details of the climate system check the CARA Climate change primer
Land surface changes can affect local temperatures not only in forests or agricultural land but also in urban areas. For example, average temperatures in downtown areas of a city can increase due to the high density of construction materials such as pavements and roofs. Higher temperatures in urban areas compared to lower temperatures in surrounding rural areas, has been called by scientists the urban heat island effect. In the following link you can find some illustrative videos on the heat island effect prepared by EPA and the Weather Channel Network. http://www.epa.gov/heatisland/about/videos.html