Detection of Dust Storms by Using Daytime and Nighttime Multi-spectral MODIS Images

Dust storms greatly affect the environment and the resources in arid and semi-arid areas. In this paper, we study the process of an Asian dust storm in the north of China in 2005 by means of Terra and Aqua MODIS data, which could monitor dust storms both in daytime and nighttime. We use three thermal infrared (TIR), 8.5 mum, 11 mum, and 12 mum, and a tri-spectral technique presented by Ackerman (1997). We find that combining brightness temperature differences BT8.5- BT11 with negative BT11- BT12 can detect dust storms in China. Furthermore, the pre-processing of images, such as cloud screening, is important for dust storm monitoring. Compared to daytime visible and near infrared RGB images, the TIR method predicted dust storm very well and could also obtain useful information in nighttime. We also analyzed dust storm motion by four MODIS images within 24 hours. Our results showed that the dust storm motions from inter land to ocean and relies on the main wind direction. This information is very important for studying the processes of dust storm.