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Titel |
Observations of NO in the upper mesosphere and lower thermosphere during ECOMA 2010 |
VerfasserIn |
J. Hedin, M. Rapp, M. Khaplanov, J. Stegman, G. Witt |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 30, no. 11 ; Nr. 30, no. 11 (2012-11-28), S.1611-1621 |
Datensatznummer |
250017288
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Publikation (Nr.) |
copernicus.org/angeo-30-1611-2012.pdf |
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Zusammenfassung |
In December 2010 the last campaign of the German-Norwegian sounding rocket
project ECOMA (Existence and Charge state Of Meteoric smoke particles in the
middle Atmosphere) was conducted from Andøya Rocket Range in northern
Norway (69° N, 16° E) in connection with the Geminid
meteor shower. The main instrument on board the rocket payloads was the
ECOMA detector for studying meteoric smoke particles (MSPs) by active
photoionization and subsequent detection of the produced charges (particles
and photoelectrons). In addition to photoionizing MSPs, the energy of the
emitted photons from the ECOMA flash-lamp is high enough to also photoionize
nitric oxide (NO). Thus, around the peak of the NO layer, at and above the
main MSP layer, photoelectrons produced by the photoionization of NO are
expected to contribute to, or even dominate above the main MSP-layer, the
total measured photoelectron current. Among the other instruments on board
was a set of two photometers to study the O2 (b1Σg+−X3Σg) Atmospheric band and NO2
continuum nightglow emissions. In the absence of auroral emissions, these
two nightglow features can be used together to infer NO number densities.
This will provide a way to quantify the contribution of NO photoelectrons to
the photoelectron current measured by the ECOMA instrument and, above the
MSP layer, a simultaneous measurement of NO with two different and
independent techniques. This work is still on-going due to the
uncertainties, especially in the effort to quantitatively infer NO densities
from the ECOMA photoelectron current, and the lack of simultaneous
measurements of temperature and density for the photometric study. In this
paper we describe these two techniques to infer NO densities and discuss the
uncertainties. The peak NO number density inferred from the two photometers
on ascent was 3.9 × 108 cm−3 at an altitude of about 99 km,
while the concentration inferred from the ECOMA photoelectron
measurement at this altitude was a factor of 5 smaller. |
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