Monitoring the Outer Region of the Neutral Atmosphere

Type Journal Article
Names S. M. Nossal, E. J. Mierkiewicz, F. L. Roesler, L. M. Haffner, R. J. Reynolds, R. C. Woodward
Publication AGU Spring Meeting Abstracts
Volume 14
Pages 01
Date May 1, 2009
Library Catalog NASA ADS
Abstract Hydrogen is a primary constituent of the geocorona and is a chemical byproduct of species below such as methane and water vapor, two greenhouse gases. The solar cycle is a dominant source of natural variability in this region and must be accounted for when isolating the effects of coupling processes from below, including that due to potential long-term change in the region. Observations by the Wisconsin H-alpha Mapper Fabry- Perot of geocoronal hydrogen Balmer-alpha emissions over solar cycle 23 have quantified a factor of 1.5 ± 0.15 higher intensities at solar maximum than at solar minimum. These observations are consistent with Fabry-Perot observations from Wisconsin during solar cycle 22. All observations have been consistently calibrated for intensity using the North American Nebula. We used the LYAO_RT radiative transfer code of Bishop to compare the observed Balmer-alpha intensities with intensities calculated using the hydrogen density distribution in the Mass-Spectrometer-Incoherent-Scatter (MSIS) model, a major empirical model used by the middle and upper atmospheric research communities. The MSIS distribution yields a solar maximum to minimum ratio similar to that observed; however, significant differences in magnitude between predicted and observed intensities highlight the need for improved upper atmospheric hydrogen density determinations.
Tags 0310 Airglow and aurora, 0328 Exosphere, 0355 Thermosphere: composition and chemistry, 1620, 3305, 3309 Climatology (1616, 4215, 8408)
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