No description available.

No description available.

The Earth Radiation Budget Experiment (ERBE) uses Angular Dependence Models (ADMs) to convert satellite observed radiances to radiative fluxes at the top of the atmosphere. Owing to errors in scene identification and to the relationship between the spatial scales of cloud systems and the spatial resolution of the ERBE scanner, the anisotropy of the radiation fields determined from ERBE observations was suspected of exhibiting a field of view size dependence. In order to remove effects due to the spatial scale of cloud fields, ERBE scanner observations from the Earth Radiation Budget Satellite (ERBS) were averaged to construct observations having a constant size field of view for all scan angles. Comparing the anisotropy for constant size fields of view with that obtained using unaltered full-resolution scanner observations, it was found that there were significant and systematic differences of the order of 5-10% for all scene types. The frequencies of occurrence for clear, partly cloudy, mostly cloudy and overcast cloud categories identified by the ERBE scene identification algorithm were calculated for the constant size field of view observations. It was found that the ERBE scene identification method failed to correctly identify scene types. A bispectral threshold method was developed for scene identification. In the determination of the thresholds, the ERBE scene identification method was assumed to be correct for nadir observations. The thresholds were then determined so that the population of scene types remained constant from nadir to limb for the constant size field of view observations. ADMs were developed using the threshold scene identification method. Results showed that the spatial-scale dependence of the ADMs was significantly reduced. The threshold ADMs satisfied the principle of reciprocity more closely than did the ERBE ADMs for all cloud categories. Using the threshold scene identification, the view zenith angle dependence of the global average albedo and the longwave flux were significantly reduced compared with those obtained using the ERBE scene identification. The estimated global average albedo increases from 0.282 for the ERBE algorithm to 0.299 for the threshold algorithm. There was no significant change for the value of the estimated longwave flux. / Graduation date: 1994

Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 134-139). / Also available by subscription via World Wide Web / xvi, 139 leaves, bound ill. 29 cm

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This study set out to examine the levels of galactic cosmic radiation exposure to Australian aircrew during routine flight operations, with particular attention to the high southern latitude flights between Australia and South Africa. Latitudes as high as 65?? South were flown to gain the data and are typical of the normal flight routes flown between Sydney and Johannesburg on a daily basis. In achieving this objective it became evident that suitable commercially available radiation monitoring equipment was not readily available and scientific radiation monitors were sourced from overseas research facilities to compliment my own FH4lB and Liulin monitors provided by UNSW. At the same time it became apparent that several predictive codes had been developed to attempt to model the radiation doses received by aircrew based on flight route, latitudes and altitudes. Further, it became apparent that these codes had not been subjected to verification at high southern latitudes and that they had not been validated for the effects of solar particle events. Initially measurements were required at the high latitudes followed by mid-latitude data to further balance the PCAIRE code to ensure reasonableness of results for both equatorial and high latitudes. Whilst undertaking this study new scientific monitors became available which provided an opportunity to observe comparative data and results. The Liulin, QDOS and a number of smaller personal dosimeters were subsequently obtained and evaluated. This appears to be the first time that such an extensive cross comparison of these monitors has been conducted over such a wide range of latitudes and altitudes. During the course of this study a fortuitous encounter with GLE 66 enabled several aspects of code validation to be examined, namely the inability of predictive codes to estimate the increased dose associated with a GLE or the effects of a Forbush decrease on the code results. Finally I review the known biological effects as discussed by numerous authors based on current epidemiological studies, with a view to high-lighting were the advent of future technology in aviation may project aircrew dose levels.