SP-168 EXPLORING SPACE WITH A CAMERA

Pictorial presentations of radiation emitted and reflected by the Earth and the atmosphere in various spectral bands have radically improved our capability to observe meteorological features from satellites. When interpreted quantitatively, these measurements lead to the description of the telluric temperature, cloud, and moisture fields. Results shown here were obtained with Nimbus 11 on May 17, 1966

Multispectral imaging can tell scientists more about the cocoon of air around the Earth than human eyes can see. It is simply a matter of combining observations made with instruments that respond to different wavelengths in the electromagnetic spectrum - a technique nicely illustrated here.

WILLIAM NORDBERG of the Goddard Space Flight Center, NASA, explains this figure this way:

"Pictorial presentations of radiation emitted and reflected by the Earth and the atmosphere in various spectral bands have radically improved our capability to observe meteorological features from satellites. When interpreted quantitatively, these measurements lead to the description of the telluric temperature, cloud, and moisture fields. Results shown here were obtained with Nimbus 11 on May 17, 1966.

"Measurements were made in the five spectral regions of: total redected solar radiation (0.2 to 4.0 microns), total emitted thermal radiation (5 to 30 microns), CO2 absorption (14 to 16 microns), the atmospheric "window" (10 to 11 microns), and water vapor absorption (6.4 to 6.9 microns) as Nimbus II passed from the south-central United States (bottom) over the Pacific, Antarctica, the Indian Ocean (center), India, and Siberia to North America. "The radiative energy balance can be determined from the difference between the first two channels. The CO: channel maps out the temperature field in the lower stratosphere, the water-vapor channel gives the moisture content in the upper troposphere, and the window channel shows Earth-surface temperatures and cloud heights. The hot surface, and moisture-laden atmosphere, of India are obvious in the picture (upper third). in emission, low-radiation intensities (cold, cloudy, or moist) are shown light; high-radiation intensities (warm, clear, dry) are dark. The reverse is depicted by reflection (0.2 to 4.0 microns)."


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