Polar-Orbiting Satellite Images

Notice to users The images include those captured by the NOAA series of polar-orbiting meteorological satellites (NOAA-15, 16 and 17 operated by the U.S. National Oceanic and Atmospheric Administration) and the Fengyun-1 series of satellites (FY-1D operated by the China Meteorological Administration). Polar-orbiting satellites revolve around the Earth along paths roughly passing over the poles. As they move, they obtain images of different parts of the Earth. One to two images are normally received in Hong Kong from each satellite every day. Orbiting at several hundred kilometres aloft, these satellites are closer to the Earth than geostationary ones and thus produce images of higher resolution. The images are taken in the infra-red region (wavelength between 10.3 and 11.3 micrometres). These images show the temperatures of cloud tops. In general, the higher the cloud top, the lower its temperature will be. The above colour scale provides a read-out of the temperature. There may be occasional signal interference and blockage by obstacles during image reception, causing black lines to appear in the image.