The Infrared Interferometer Experiment on Nimbus 3

Abstract

The Michelson interferometer experiment carried on the Nimbus 3 satellite has successfully obtained thermal emission spectra of the earth and atmosphere between 400 and 2000 cm−1 with a resolution equivalent to 5 cm−1. Comparison of a measured spectrum with a spectrum calculated theoretically from near‐simultaneous radiosonde measurements indicates generally good agreement over most of the spectral range covered. A preliminary search for spectral features attributable to minor atmospheric constituents other than CO2 H2O, and O3 has resulted in a positive identification of only CH4 thus far. Comparisons of temperature profiles estimated from selected spectra with those obtained from radiosonde measurements on an individual basis and in the form of maps for selected locations and times indicate that meaningful atmospheric temperatures can be obtained, even in the presence of clouds. Similar comparisons of water vapor estimates with radiosonde measurements demonstrate that good humidity profiles can be obtained under almost clear sky conditions, but, when clouds are present within the field of view, the estimates become unreliable. Total ozone amounts in an atmospheric column obtained from the spectra are in generally good agreement with Dobson spectrometer measurements, and the estimates are found to be insensitive to clouds within the field of view under most circumstances. A global map of ozone, constructed from data taken over a 24‐hour period, shows anticipated correlations with a conventional 300‐mb pressure height map in the northern hemisphere. The possibility of obtaining information on surface composition is investigated by using a spectrum obtained over Egypt that shows a depression of as much as 10°K in brightness temperature in parts of the atmospheric window. This effect can be attributed to reststrahlen due to the presence of SiO2 in the desert soil.

Meteorological fields from remote infrared sensing

“…However, despite the large difference between retrieved and observed profiles, the mean temperatures of the 1 to 0.1 kPa layer differ by only 0.4K. Conrath et al (1970) have compared the temperature field at 50 kPa (500 mb) over the northern hemisphere as obtained from IRIS B with the temperature field obtained from radiosondes. Despite the differences in time of observation (up to 12 h) between many of the satellite temperatures and the corresponding radiosonde temperatures the patterns obtained are similar.…”

Airborne observations of far-infrared upwelling radiance in the Arctic

“…Conrath et al, 1970). Most instruments currently deployed, such as the Moderate Resolution Imaging Spectroradiometer (MODIS; King et al, 2003), the Atmospheric Infrared Sounder (AIRS; Aumann et al, 2003) and the Infrared Atmospheric Sounding Interferometer (IASI; Blumstein et al, 2004), do not measure atmospheric radiation beyond approximately 15 µm, though, because sensing far-infrared radiation (FIR; 15 µm < λ < 100 µm) generally requires a different technology (Mlynczak et al, 2006).…”

An improved method for determining the vertical ozone distribution using satellite measurements.

“…Two wavelength 1339 regions, infrared and ultraviolet can be used to infer atmospheric ozone distributions from satellite nadir measurements. The technique utilizing infrared atmospheric radiances has been developed and used by PRABHAKARA (1969) and CONRATH et al (1970). The use of atmospheric backscattered ultraviolet (BUV) was developed by SINGER and WENTWORTH (1957) and TWOMEY (1961).…”