Results of a Survey of IGY Patrol Spectra at College, Alaska

Thumbnail
Name:
GI Reports 113.pdf
Size:
1.416Mb
Format:
PDF
Download
Author
Herman, L.
Belon, A. E.
Metadata
Show full item record
URI
http://hdl.handle.net/11122/3643
Abstract
The behavior of prominent auroral emissions has been studied statistically using the IGY patrol spectrograms obtained at College, Alaska during the International Geophysical Year. Results are presented in the form of mean diurnal intensity variations and in the form of correlation tables. Both presentations suggest the occurrence of two types of auroras. One is relatively weak, has a broad intensity maximum around magnetic midnight, and contains the hydrogen Balmer emissions. The other gradually increases in intensity until magnetic midnight and thereafter maintains a high intensity level until dawn. Its spectrum is usually characterized by the presence of the first positive bands of N2. The mean diurnal intensity variation of the sodium emission suggests that the twilight enhancement of the sodium D-lines persists to much greater solar depression angles than those previously reported. Some evidence is found for a small auroral contribution to the sodium emission. This contribution is however erratic and does not correlate well with any specific auroral emission. The (OI) 6364A emission shows, as expected, a strong twilight enhancement persisting to large solar depression angles. No enhancement is observed for the (OI) 5577A emission. A weak correlation is found between the intensity of the hydrogen Balmer emissions and the occurrence of red auroras.
Description
FOREWORD -- This report is an enlarged and revised version of an original study conducted by one of us (HERMAN, 1960 ). Several additional emissions of the auroral spectrum are studied. In order to ascertain and clarify some unexpected results of the original study the spectroscopic data has been re-classified into three well defined groups which are analysed separately. Data of questionable quality are removed. It appears that this new study resolves ambiguities present in the original results and allows revised and new interpretations to be advanced.
Table of Contents
Abstract -- Introduction : Instrumentation ; Radiations measured ; Intensity estimates -- Mean Diurnal Intensity Variation of Prominent Emissions : H-alpha ; First positive system of N2 ; Second positive system of N2 ; First negative system of N2 ; Red oxygen line 6364A - 2/1 (OI) ; Green oxygen line 5577A - 3/2 (OI) ; Sodium D-lines -- Spectral intensity Distribution in the Aurora -- Classification of Auroral Spectra : Type B (low altitude) ; Type AB ; Type A ; High latitude airglow ; Abnormal spectra - Fast proton spectra sodium emission -- Appendix -- Acknowledgements -- References
Date
1961-03
Source
Geophysical Institute
Publisher
Geophysical Institute at the University of Alaska
Type
Report
Peer-Reviewed
Yes
Collections