Title page for ETD etd-05222007-091347


Type of Document Dissertation
Author Tira, Nour E.
URN etd-05222007-091347
Title A study of the thermal and optical characteristics of radiometric channels for earth radiation budget applications
Degree PhD
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Mahan, James Robert Committee Chair
Keywords
  • Terrestrial radiation.
  • Radiometers.
Date of Defense 1991-12-01
Availability restricted
Abstract
An improved dynamic electrothermal model for the Earth Radiation Budget Experiment (ERBE) total, nonscanning channels is formulated. This model is then used to accurately simulate two types of dynamic solar observation: the solar calibration and the so-called pitchover maneuver. Using a second model, the nonscanner active cavity radiometer (ACR) thermal noise is studied. This study reveals that radiative emission and scattering by the surrounding parts of the nonscanner cavity are acceptably small. The dynamic electrothermal model is also used to compute the ACR instrument transfer function. Accurate in-flight measurement of this transfer function is shown to depend on the energy distribution over the frequency spectrum of the radiation input function. A new array-type field-of-view (FOV) limiter, whose geometry controls the input function, is proposed for in-flight calibration of an ACR and other types of radiometers. Finally, the point spread function (PSF) of the ERBE and the Clouds and Earth's Radiant Energy System (CERES) scanning radiometers is computed. This PSF is useful

in characterizing the channel optics. It also has potential use for recovering the distribution of the radiative flux coming from the Earth by its deconvolution with satellite measurements.

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