HR: 1340h
AN: SA23A-1128    [Abstracts]
TI: Observing Nitric Oxide in the Polar Night by Stellar Occultation
AU: * Lumpe, J D
EM: lumpe@cpi.com
AF: Computational Physics, Inc., 1650 38th St., Suite 105W, Boulder, CO 80301, United States
AU: Bailey, S
EM: baileys@vt.edu
AF: Virginia Tech University, Bradley Department of Electrical and Computer Engineering, 302 Whittmore Hall, Blacksburg, VA 24061, United States
AU: McClintock, B
EM: Bill.McClintock@lasp.colorado.edu
AF: University of Colorado, Laboratory for Atmospheric and Space Physics, 392 UCB, Boulder, CO 80309, United States
AU: Randall, C
EM: randall@lasp.colorado.edu
AF: University of Colorado, Laboratory for Atmospheric and Space Physics, 392 UCB, Boulder, CO 80309, United States
AB: It is now understood that NO plays a key role in the coupling of the stratosphere, mesosphere and lower thermosphere (SMLT) via energetic particle precipitation. A significant body of evidence suggests that NO created by energetic particles is transported to the lower atmosphere during polar night, where it participates in catalytic ozone destruction. To date, measurements of the highly variable NO abundance have only been made during sunlit conditions and the lack of nighttime NO measurements is a significant impediment to developing a quantitative understanding of the role played by this crucial species. We describe a space-based experiment designed to make the first measurements of NO concentration in the polar night, using the method of stellar occultation. Our approach will utilize a moderately high resolution (~90 mA) spectral measurement of NO absorption in either the δ-band at ~193 nm or the γ-band at ~215 nm. These two band features are compared to optimize tradeoffs between measurement signal-to-noise, the NO absorption strength and contamination due to competing absorption sources. The latter is primarily caused by O2 absorption in either the Schumann-Runge bands (193 nm) or the Hertzberg continuum (215 nm). We quantify the measurement capabilities required to obtain vertical profiles of NO between 70 and 150 km in the polar night, and show that an instrument with appropriate light gathering capability can be made with mass and dimensions appropriate for sounding rockets and small satellites. The expected horizontal sampling density provided by the available target stars is sufficient to characterize the polar night region. We will also describe both laboratory measurements and a planned rocket experiment which will demonstrate the viability of the stellar occultation technique.
DE: 0340 Middle atmosphere: composition and chemistry
DE: 0355 Thermosphere: composition and chemistry
DE: 0394 Instruments and techniques
DE: 2716 Energetic particles: precipitating
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting