Indirect Measurements of Atmospheric Temperature Profiles From Satellites: Iii. The Spectrometers and Experiments

Abstract

Three spectrometers and associated experiments are described. The work reviewed comprises the early experimental phases of a program to develop a satellite infrared spectrometer capable of making radiometric measurements in the 15-micron carbon dioxide band needed for deduction of atmospheric temperature profiles. Initially, a simplified, breadboard spectrometer with four spectral channels was used to determine the temperature profile of the lower atmosphere from the ground. Next, a commercial spectrophotometer was modified and another determination of the atmospheric temperature profile was made using more spectral intervals. Instrument specifications for a balloon flight model spectrometer were aerived from these experiments. Following the model's fabrication, testing, and calibration, two high-altitude balloon flights were conducted to demonstrate that the atmospheric temperature profile could be ascertained from above the atmosphere.

Atmospheric Infrared Sounder (AIRS) sounding evaluation and analysis of the pre‐convective environment

“…The usefulness of measuring atmospheric T and WV in order to diagnose the state of the atmosphere lead to the development of satellite‐based sounding instruments over 40 years ago [ Hilleary et al , 1966; James , 1967; Yates , 1970; Chesters et al , 1986], beginning with the U.S. Satellite Infrared Spectrometer (SIRS) and Infrared Interferometer Spectrometer (IRIS) onboard Nimbus 3, launched in 1969 [ Wark and Hilleary , 1969; Hayden , 1971; Wick , 1971; Smith , 1972]. SIRS and IRIS were capable of remotely sensing atmospheric T structures by using statistical relationships and regression methods [ Kaplan et al , 1977; Westwater and Strand , 1968; Smith et al , 1970; Crosby et al , 1973; Fritz , 1977].…”

Indirect Measurements of Atmospheric Temperature Profiles From Satellites: V. Atmospheric Soundings From Infrared Spectrometer Measurements at the Ground

“…It has been pointed out [IO] that when experimental data with relatively small errors are used in equation (l), the errors in the resulting solution can be enormously large. This observation was clearly demonstrated [5] when the "breadboard" model of the satellite infrared spectrometer was used to sound the atmosphere from the ground t o provide experimental data for preliminary analyses. During those experiments, however, the satellite spectrometer incorporated only four frequency channels.…”

“…The spectrometer response was calibrated as a function of spectral radiance with two blackbodies [5]. The block diagram for calibration and observation is shown in figure 1.…”

Satellite studies of the lower atmosphere

“…A variety of instrumental techniques will be used including conventional, fixed grating, multidetector spectrometers, Michelson interferometers, and spectrometers in which spectral separation is achieved by rotating wedges of continuous interference layers. (Hilleary et al 1966, Hanel and Chaney 1966,5 Hovis 1966. Improvements i n spatial and spectral resolution by about one to two orders of magnitude can be expected when highly cooled infrared detectors (77'K) can be accommodated routinely on spacecraft.…”

“…Complete temperature profiles have not yet been measured from satellites, but plans for such measurements exist and encouraging results have been obtained from attempts at inverting radiometric data taken with balloon borne instruments (Hilleary et al, 1966).…”