Notice to users

• Infra-red images show the temperatures of the observed objects (e.g. clouds). Such "night vision" capability makes them useful round the clock. In general, the higher the top of the clouds, the lower its temperature and the brighter it will appear in the image.
• Visible images liken the black-and-white photos captured from space. They are available in day time only. The resolution of visible images is higher than those of infra-red images. This enables visible images to show more detailed structure of clouds.
• Some minor processing of the images has been made by the Observatory for visual presentation.
• The animation sequence consists of past 24 satellite images taken at half-hourly or hourly intervals.
• The time of the satellite image represents the time when satellite data are completely received at the ground reception system. Usually, it will take half to one hour to process the satellite data, generate the satellite image and upload it to the website.
• The images were originally captured by Fengyun-2D (FY-2D), a geostationary meteorological satellite operated by China Meteorological Administration (CMA). Anyone wishing to further disseminate these satellite images should seek permission from CMA (Address: China Meteorological Administration, No. 46, Zhongguancun Nandajie, Beijing, China).
• FY-2D is located above the Equator at longitude 86^oE, and some 35,800 km away. As it follows the Earth's rotation closely, it is stationary relative to the Earth's surface (hence the name 'geostationary'). This enables it to view, and obtain images of, the same part of the Earth all the time. An animation of the image sequence helps bring out the movement and development of clouds.