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Measuring weather
Satellites and their instruments can measure temperature, humidity, winds, chemicals in the atmosphere, snow cover, vegetation, precipitation, and other features. Many even observe extraterrestrial bodies, giving solar and space information. These capabilities, coupled with the great areal coverage they provide, make them very welcome additions to our Earth-based observations. You may recall from earlier sections on ASOS, Radiosonde and Radar that in situ observational coverage is far from complete. The satellites help fill the gaps. They are particularly important for weather that develops over the oceans, such as hurricanes. While there are a few land- and air-based observations of hurricanes, satellites provide continuous data. A number of satellites, like GOES and its polar-orbiting cousin, POES, have sounding instruments onboard. These radiometers observe layer mean temperature and moisture, a vertically smoothed version of what a radiosonde would observe throught the height of the atmosphere. Satellites "see" the earth using 19 different channels. The various channels observe various features. For instance, Channel 2 observes longwave emission from carbon dioxide to calculate temperatures in the upper atmosphere, and Channel 12 observes midwave emission from water vapor to derive moisture content in the upper atmosphere. Unfortunately, these instruments cannot "see" through clouds, but they do yield exceptional observations where they can see. In addition to sounding capabilities, many satellites, like GOES, carry an imager instrument. The imager radiometer on GOES performs observations in 5 channels: visible, shortwave, moisture, and two infrared channels. Observations are used to produce a two-dimensional picture of various atmospheric fields. The whole continental United States can be scanned in 41 seconds! Next page -> remote observations, satellite
Links and resources
Satellites and their instruments can measure temperature, humidity, winds, chemicals in the atmosphere, snow cover, vegetation, precipitation, and other features. Many even observe extraterrestrial bodies, giving solar and space information. These capabilities, coupled with the great areal coverage they provide, make them very welcome additions to our Earth-based observations. You may recall from earlier sections on ASOS, Radiosonde and Radar that in situ observational coverage is far from complete. The satellites help fill the gaps. They are particularly important for weather that develops over the oceans, such as hurricanes. While there are a few land- and air-based observations of hurricanes, satellites provide continuous data. A number of satellites, like GOES and its polar-orbiting cousin, POES, have sounding instruments onboard. These radiometers observe layer mean temperature and moisture, a vertically smoothed version of what a radiosonde would observe throught the height of the atmosphere. Satellites "see" the earth using 19 different channels. The various channels observe various features. For instance, Channel 2 observes longwave emission from carbon dioxide to calculate temperatures in the upper atmosphere, and Channel 12 observes midwave emission from water vapor to derive moisture content in the upper atmosphere. Unfortunately, these instruments cannot "see" through clouds, but they do yield exceptional observations where they can see. In addition to sounding capabilities, many satellites, like GOES, carry an imager instrument. The imager radiometer on GOES performs observations in 5 channels: visible, shortwave, moisture, and two infrared channels. Observations are used to produce a two-dimensional picture of various atmospheric fields. The whole continental United States can be scanned in 41 seconds! Next page -> remote observations, satellite
Links and resources
