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Global variation in the 2.7 µm NO overtone limb‐emission from the lower thermosphere
Author(s) -
Sharma R. D.,
Wheeler N. B.,
Wise J. O.,
Dothe H.,
Duff J. W.
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl010925
Subject(s) - thermosphere , overtone , radiance , atmospheric sciences , mesosphere , physics , aeronomy , altitude (triangle) , atmosphere (unit) , rotation (mathematics) , ionosphere , atomic physics , environmental science , optics , meteorology , stratosphere , spectral line , astronomy , geometry , mathematics
The overtone vibration‐rotation band (Δv=−2) limb‐emission from NO around 2.7 µm observed by the Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS‐1A) at 120 km tangent altitude is shown to arise from the nascent molecule produced by the reactions of N( 4 S) and N(²D) atoms with O 2 . Measurement of the 2.7 µm emission from NO therefore permits modeling of the local rate of production of NO, a quantity important in odd nitrogen chemistry in the thermosphere. The 2.7 µm limb‐radiance in the nonauroral region is observed, above the instrument noise level, only during the day and shows about a factor of 2 variation indicating a similar variation in the rate of production of NO. In the aurorally dosed region however the observations lead to about an order of magnitude variation in this rate.