Short Name:

First ISCCP Regional Experiment (FIRE) Cirrus Phase II Spectral Radiance Experiment (SPECTRE) SIRIS High Resolution Emission Data

The First ISCCP Regional Experiments have been designed to improve data products and cloud/radiation parameterizations used in general circulation models (GCMs). Specifically, the goals of FIRE are (1) to seek the basic understanding of the interaction of physical processes in determining life cycles of cirrus and marine stratocumulus systems and the radiative properties of these clouds during their life cycles and (2) to investigate the interrelationships between ISCCP data, GCM parameterizations, and higher space and time resolution cloud data. To-date, four intensive field-observation periods were planned and executed: a cirrus IFO (October 13 - November 2, 1986); a marine stratocumulus IFO off the southwestern coast of California (June 29 - July 20, 1987); a second cirrus IFO in southeastern Kansas (November 13 - December 7, 1991); and a second marine stratocumulus IFO in the eastern North Atlantic Ocean (June 1 - June 28, 1992). Each mission combined coordinated satellite, airborne, and surface observations with modeling studies to investigate the cloud properties and physical processes of the cloud systems.SPECTRE/SIRIS high spectral resolution observations were obtained at Coffeyville, Kansas in November - December 1991. The SIRIS instrument has been previously flown for balloon-borne studies of stratospheric chemistry relevant to the ozone cycles. It is a modified version of a Bomem continuously scanning Fourier transform spectrometer, operating in emission mode. The following instrument parameters were applicable for the Coffeyville SPECTRE campaign. The field-of-view, 0.5 degrees full width at half-maximum, was directed towards the zenith, except for a day when limb were recorded. The highest emission-mode spectral resolution recorded during SPECTRE was taken by SIRIS 0.06 cm-1, apodized. Scan times varied from one to a few minutes, depending onthe resolution. The instrument was run at ambient temperature, withthe Si:Ga detectors at liquid helium (LHe) temperature. Data are limited by photon noise from the emission from the instrument and from the atmosphere itself. Therefore data were recorded with two different width bandpasses: 1) narrow bandpass cooled filters in channels 1-4, which reduces the background noise, yielding higher signal-to-noise; and 2) wide band in channel 5 for more complete spectral coverage.It was the goal of SPECTRE to acquire clear-sky radiance spectra under a variety of temperature and water vapor conditions.

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