China: Data from NASA's QuikScat satellite have revealed that between 2000 and 2009, the Chinese capital of Beijing has quadrupled in its physical extent. A team led by NASA's Jet Propulsion Laboratory and Mark Jacobson of Stanford University used QuikScat data to measure infrastructure changes, like new buildings and roads. To study how the urban growth has changed Beijing's wind patterns and pollution, the scientists used a computer model of climate and air quality. It was discovered that winter temperatures have increased by 5 to 7 degrees Fahrenheit and wind speed has reduced by about 2 to 7 miles per hour. The stagnant city air has also increased ground-level ozone pollution. Jacobson explains the reason behind these changes. He tells that buildings slow down winds by blocking the air and creating friction. And temperatures rise because covering soil with concrete reduces evaporation. And evaporation is necessary for cooling the Earth.
Source: NASA
