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Satellite Image DetailsThese images are generated by geostationary satellites orbitting 22,000 miles above the equator. These include visible, infrared and water vapor images. The images are updated once an hour at 50 after the hour. Visible Satellite Image
This image is the equivalent of taking a black and white photo of the earth. The bright areas show where the sun is being reflected back into space as a result of clouds or snow cover. Clouds and snow show up white. The thicker the cloud, the brighter the color. Land surfaces show up as gray and ocean surfaces nearly black. The major limitation to visible imagery is that it is only valid during daylight. There are 5 sectors for the visible image:
Infrared Satellite Image
This type of image shows heat based radiation from the infrared spectrum. In other words, the warmer the surface, the more infrared radiation it emits. For a satellite image, cooler surfaces are bright and warmer surfaces are dark. Since the atmosphere cools as you increase in altitude, clouds would show up as bright areas and land surfaces as dark areas. In addition, low clouds will be more gray and higher clouds will show up more white. Tall thunderstorm clouds will show up as bright white and fog will be hard to decern from land areas. A large advantage of IR is that you can view it 24 hours a day. There are 5 sectors for the visible image:
Enhanced Infrared Satellite Image
This is an infrared image enhanced to highlight the cloud areas and the coldest cloud tops. Since, IR images could be used to determine cloud height, these images are enhanced to highlight the highest, coldest cloud tops. Areas of strong precipitation will show up as shades of cyan. Thunderstorms will show up in blue and green. In addition, the contrast of warmer clouds is increased so that low clouds will show up. A color bar at the bottom of the image will describe the enhancement scheme. The tick marks at the top of the bar represent 10 degree Celsius increments starting at 50C on the left and going to -110C on the right. The colored regions represent: Water Vapor Satellite Image
The water vapor image show an infrared band which is affected strongly by the presence of water vapor. Essentially, the image shows the altitude of the highest moist layer in the atmosphere. Bright areas reflect the location of high clouds either due to jet stream cloudiness or due to thunderstorm activity. The dark areas reflect the location of dry are at high altitudes. This is associated with dry air intrusion and sinking motion associated with high pressure systems. This image is a decent tracer of jet stream winds which will show up as bright streaks. There are 4 sectors for the water vapor image:
Composite Satellite Surface Map
This is the infrared satellite image overlaid with the current surface weather map. Composite Infrared Satellite and Radar Summary
This is the infrared image overlaid with the radar summary. The infrared image will
highlight the deeper/higher clouds as bright white and the radar summary allows you to
correlate the high clouds with precipitation. The radar summary is stippled so that the
image will partially show through the radar summary. |