Physics & Astronomy ETDs

Publication Date

2-24-1969

Abstract

Ground-based observations of cosmic-ray intensity have the disadvantage of being more sensitive to variations of atmospheric temperature and pressure than to the more interesting variations in the primary cosmic radiation. It is, therefore, imperative to correct the recorded cosmic-ray intensity for variations of atmospheric origin before studies can be made of the smaller variations of the primary cosmic ray intensity.

In this thesis an attempt has been made to remove the variations of atmospheric origin from the cosmic-ray intensity recorded simultaneously by a neutron monitor and a meson telescope located at Albuquerque, New Mexico. It was found that the neutron monitor data could be satisfactorily cor­rected for variations of barometric pressure with a barometer coefficient of -.79%/mb; since a neutron monitor is relatively insensitive to temperature variations, temperature corrections were not made.

Two different empirical methods were used to try to cor­rect the meson data for the variations of atmospheric origin. One method used a multiple regression analysis to fit the ob­served variations of cosmic-ray intensity to the variations in the ground-level pressure and temperature and the variations of the barometer corrected neutron intensity; the other method compared the diurnal variations of the above variables. Both methods made use of the ground-level temperature, since no other temperature data were readily available. These two correction methods did not prove adequate, confirming the fact that the observed variations in meson intensity depend on the temperature distribution throughtout the atmosphere. Barometer variations were satisfactorily removed from the meson data using a total barometer coefficient of -.22%/mb.

By a comparison of the neutron and meson intensities, the magnitude of the atmospheric temperature contribution to the meson diurnal variation was found to be 0.16%/mb with a maximum at 0600 hours local time. This value is larger than that found by other researchers in different locations, indicating that at Albuquerque the temperature effects are appreciable. This confirms the fact that for a surface meson monitor, atmospheric effects are of a magnitude comparable to the primary diurnal variation, and are difficult to re­move, especially at Albuquerque where the daily atmospheric changes are both large and variable.

Degree Name

Physics

Level of Degree

Masters

Department Name

Physics & Astronomy

First Committee Member (Chair)

Derek B. Swinson

Second Committee Member

Victor H. Regener

Third Committee Member

Christopher Pratt Leavitt

Language

English

Document Type

Thesis

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