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Infrared glow above thunderstorms?
Author(s) -
Picard R. H.,
Inan U. S.,
Pasko V. P.,
Winick J. R.,
Wintersteiner P. P.
Publication year - 1997
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 - 10.1029/97gl02753
Subject(s) - radiance , physics , atomic physics , radiative transfer , infrared , electron , spectral line , emission spectrum , ionosphere , computational physics , materials science , optics , geophysics , quantum mechanics , astronomy
Sustained heating of lower ionospheric electrons by thundercloud fields, as recently suggested by Inan et al. [1996], may lead to the production of enhanced infrared (IR) emissions, in particular 4.3‐ µ m CO 2 emission. The excitation rate for N 2 (v) via electron collisions is calculated using a new steady‐state two‐dimensional electrostatic‐heating (ESH) model of the upward coupling of the thundercloud (TC) electric fields. The vibrational energy transfer to CO 2 and 4.3‐ µ m radiative transfer are then computed using a line‐by‐line non‐LTE (non‐local thermodynamic equilibrium) radiation model. Limb‐viewing radiance profiles at 4.3‐ µ m and typical radiance spectra are estimated for five different TC charge distributions and ambient ionic conductivities. Broadband 4.3‐ µ m enhancements of greater than a factor of two above ambient nighttime levels are predicted for tangent heights (TH) in the range ∼80 to >130 km for the most perturbed case, with larger enhancements in selected narrower spectral regions. The predicted IR enhancements should be observable to an orbiting IR sensor.