Satellite remote sensing of thermospheric O/N{sub 2} and solar EUV 2. Data analysis
- Computational Physics, Inc., Fairfax, VA (United States)
- Phillips Lab., Hanscom, MA (United States)
The companion paper by Strickland et al. describes a technique for deriving Q{sub EUV} and O/N{sub 2} from disk observations of OI 135.6 nm and N{sub 2} LBH dayglow emission. Q{sub EUV} refers to the integrated solar EUV energy flux below 45 nm and is derived from knowledge of the 135.6/LBH ratio or O/N{sub 2} in conjunction with either the 135.6 nm or LBH intensity. Strickland et al. show that the least uncertainty in derived values O/N{sub 2} occurs in the vicinity of an N{sub 2} depth of 10{sup 17}cm{sup {minus}2}. While Q{sub EUV} is obtained from the intensity of either 135.6nm or LBH, O/N{sub 2} is obtained from the intensity ratio designated by 135.6/LBH. The technique has been used to derive O/N{sub 2} and Q{sub EUV} values from nadir-viewing far ultraviolet dayglow data obtained by the auroral and ionospheric remote sensor instrument on board the Polar BEAR satellite. Data are considered from single passes on July 15, 16, and 21, 1987, spanning a latitude range from 25 to 55{degrees}N. The 3-hour ap index was between 20 and 30 for the first two passes and only about 5 for the third pass. The 135.6nm and LBH signals were obtained from spectra recorded at a resolution of 3.6 nm from which a background was subtracted followed by ingegration over the intervals from 134.5 to 139.0 nm and 155.0 to 170.0 nm. Uncertainties were assigned to the signals and their ratios that took into account statistical uncertainties in the true signal and in the subtracted background signal. Profiles of derived O/N{sub 2} with uncertainties reflecting the data undertainties are shown along with mass spectrometer/incoherent scatter O/N{sub 2} profiles over 25 - 55{degrees}N. In all cases, O/N{sub 2} increases from high to low latitudes. Derived Q{sub EUV} values are in the range from 1.1 to 1.4 ergs cm{sup {minus}2}s{sup {minus}1} and are in good agreement with values derived from the Hinteregger spectrum for the F{sub 10.7} values appropriate to the observations.
- OSTI ID:
- 223574
- Journal Information:
- Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A7 Vol. 100; ISSN JGREA2; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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