Open AccessObservations of infrared radiative cooling in the thermosphere on daily to multiyear timescales from the TIMED/SABER instrument
Author(s) -
Mlynczak Martin G.,
Hunt Linda A.,
Thomas Marshall B.,
MartinTorres F. Javier,
Mertens Christopher J.,
Russell James M.,
Remsberg Ellis E.,
LópezPuertas Manuel,
Picard Richard,
Winick Jeremy,
Wintersteiner Peter,
Thompson R. Earl,
Gordley Larry L.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009ja014713
Subject(s) - thermosphere , radiative cooling , atmospheric sciences , radiative transfer , radiative flux , environmental science , atmosphere (unit) , airglow , physics , ionosphere , astrophysics , meteorology , geophysics , quantum mechanics
We present observations of the infrared radiative cooling by carbon dioxide (CO 2 ) and nitric oxide (NO) in Earth's thermosphere. These data have been taken over a period of 7 years by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the NASA Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics (TIMED) satellite and are the dominant radiative cooling mechanisms for the thermosphere. From the SABER observations we derive vertical profiles of radiative cooling rates (W m −3 ), radiative fluxes (W m −2 ), and radiated power (W). In the period from January 2002 through January 2009, we observe a large decrease in the cooling rates, fluxes, and power consistent with the declining phase of solar cycle 23. The power radiated by NO during 2008 when the Sun exhibited few sunspots was nearly one order of magnitude smaller than the peak power observed shortly after the mission began. Substantial short‐term variability in the infrared emissions is also observed throughout the entire mission duration. Radiative cooling rates and radiative fluxes from NO exhibit fundamentally different latitude dependence than do those from CO 2 , with the NO fluxes and cooling rates being largest at high latitudes and polar regions. The cooling rates are shown to be derived relatively independent of the collisional and radiative processes that drive the departure from local thermodynamic equilibrium (LTE) in the CO 2 15 μ m and the NO 5.3 μ m vibration‐rotation bands. The observed NO and CO 2 cooling rates have been compiled into a separate data set and represent a climate data record that is available for use in assessments of radiative cooling in upper atmosphere general circulation models.