Engineering topics
Publications and source records attributed to Green, R..
As a calibrated imaging spectrometer flying at a 20 km altitude, AVIRIS may contribute to the Landsat and the Advanced Land Remote Sensing System efforts. These contributions come in the areas of: 1) on-orbit calibration, 2) specification of new spectral bands, 3) validation of algorithms and 4) investigation of an imaging spectrometer for the Advance Land Remote Sensing System.
This paper describes recent improvements in the AVIRIS data facility.
The AVIRIS onboard calibrator became operational in 1992. This subsystem on the AVIRIS sensor has operated nominally throughout the 1992 and 1993 flight season. This paper describes the data measured by the onboard calibration and the two primary uses of these data.
In this study, a Modtran-based calibration approach was used to map liquid water and atmospheric water vapor and retrieve surface reflectance from three AVIRIS scenes acquired in 1992 over the Jasper Ridge Biological Preserve. Temporal trends in endmember fractions, liquid water and atmospheric water vapor were investigated also. The combination of spectral mixture analysis and the Modtran based atmospheric/liquid water models was used to develop a unique vegetation community description.
In this paper, we describe an experiment to calibrate the Optical Sensor on board the Japanese Earth Resources Satellite-1 with data acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). This experiment establishes the suitability of AVIRIS for the calibration of spaceborne sensors in the 400 to 2500 nm spectral region.
The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is an imaging spectrometer that measures spatial images of the total up welling spectral radiance from 400 to 2500 nm at 10 nm spectral intervals. Quantitiative research and application objectives for surface investigations require conversion of the measured radiance to surface reflectance or surface leaving radiance. In this paper we describe a set of algorithms to estimate aerosol optical depth, atmospheric water vapor, and surface pressure height from the AVIRIS measured radiance.
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This paper describes the Earth Radiation Budget Experiment (ERBE) data products being made available to the community. The Science Team used ten validation criteria to judge the acceptability of the data for archival. These criteria are listed, and uncertainty estimates based on them for four typical data products are presented. A brief description of the radiation budget for April 1985 from the combined data of ERBE and NOAA-9 concludes this paper.
The Earth Radiation Budget Experiment (ERBE) involves the use of a system of three spacecraft with instrument packages for measuring the earth's radiation balance to an accuracy which has been unattainable in previous experiments. The experiment is to determine the monthly averaged radiant exitances at te 'top of the atmosphere' (TOA) over the earth with a resolution of 250 km. The realization of this goal requires the conduction of high accuracy measurements, and the computation of the instantaneous radiant exitances from these measurements. The operation involved in this computation is called an 'inversion'. A third requirement is related to the computation of the daily and monthly averaged regional values from the instantaneous values. A brief description is provided of the algorithms for the inversion of the measurements to TOA radiant exitances, taking into account also the techniques which are used to validate the methods and results.
The NASA plans for FUSE, a satellite which obtains spectra with resolutions between 100,000 and 100 in the spectral regions from 912 to 1216A and 100 to 912A, are outlined. Scientific problems which can be tackled by FUSE, but not by IUE or the Space Telescope, are discussed. A grazing incidence echelle and a hybrid echelle design are presented. They have high throughput, large simultaneous spectral range, and low background photon counting statistics. The satellite operational organization is similar to that of IUE.
IUE observations indicate that the spectrum of 3C 273 is similar to that of other large-redshift quasars. There is a large excess of flux in the range 2400 A to 5300 A, which encompasses the Balmer jump region but which does not appear to be explainable by Balmer emission. The intensity ratio of Lyman-alpha to H-beta is 5.5, in agreement with other measures and a factor 6 smaller than the recombination value. The only absorption lines in the spectrum are due to our Galaxy. There is marginal evidence for a depression of the continuum shortward of the Lyman-alpha emission line, but the errors are too large to warrant any conclusion that 3C 273 has a rich absorption-line spectrum such as that seen in large-redshift quasars. The absence of emission and absorption lines of Fe II leads to the conclusion that resonance fluorescence probably produces the visual Fe II emission lines.
Positron annihilation rates in lanthanum hydrides of various composition
Mood, motility, and 17-hydroxycorticoid excretion in cyclic manic-depressive patient