What weather conditions do the different colors on the satellite cloud map represent?
In black and white infrared satellite cloud photos, we see that some places are white, some places are black, and other places are gray, etc. So what do these colors mean? We know that if the surface of the earth is a clear sky area, what the satellite observes is the infrared radiation information emitted from the ground to space, which appears as black and gray on the satellite cloud map. The darker the black, the stronger the ground radiation and the clearer the weather. When the sky above a certain place is covered with clouds and rain, what the satellite observes is the infrared radiation emitted from the cloud tops to space, which appears as white or off-white. White means that the ground radiation is very weak, the temperature is very low, the cloud system in the satellite cloud image is very dense, and the rainfall intensity is very high. The transition zone between the clear sky area and the cloud and rain area is usually covered by dark gray, gray, and light gray cloud systems, indicating that there are clouds of different thicknesses without obvious precipitation. On satellite cloud images displayed on television, the surface and ocean are often represented in green and blue.
Visible light cloud images taken from space by meteorological satellites are taken using the scattered light produced by the coarse scattering of sunlight by cloud droplets and ice crystals. White on the cloud map indicates strong reflection of sunlight, while gray and black areas indicate weak reflection. Since land has a higher reflectivity than oceans, land appears gray and oceans appear black on visible light cloud maps, while areas covered by ice, snow and deep clouds generally appear white.
One advantage of using infrared cloud images is that they can provide cloud cover and air mass temperature information day and night, while visible light cloud images only provide data during the day.
Of course, to accurately interpret the information contained in satellite cloud images, it is best to use both cloud images in combination.
Satellite cloud images are cloud pictures received from meteorological satellites on the ground. According to the flight orbit of meteorological satellites, they can be divided into two types: polar orbit meteorological satellite cloud images and geostationary orbit meteorological satellite cloud images. The former's continuous pictures represent cloud conditions at different locations; the latter's continuous pictures represent the continuous conditions of clouds in the same range below the satellite. According to the different instruments used to obtain cloud conditions from meteorological satellites, they can be divided into visible satellite cloud images and infrared satellite cloud images.
If there is a clear sky area above a certain place, what the satellite observes is the infrared radiation information sent from the ground to space, which appears as black and gray; the darker the black, the stronger the ground radiation and the higher the temperature. , the sunny the weather the better. When there is cloud and rain covering a certain area, what the satellite observes is the infrared radiation information sent from the cloud top to space, which appears as white or off-white; the whiter the color, the weaker the ground radiation, the lower the temperature, and the thicker the cloud system. The denser it is, the greater the rainfall intensity. The transition area between the clear sky area and the cloud and rain area is a dark gray, gray, and light gray cloud system, indicating that there are clouds of different thicknesses without obvious precipitation.