Physical Sciences

Atmospheric Optics.

Atmospheric Optics

ARCON scientists have a longstanding research interest in the middle atmosphere (stratosphere, mesosphere, lower thermosphere) and the optical emissions of molecules in this region. Our efforts in this field have included the development and deployment of physics-based models; analysis of data from rocket and satellite-borne detectors; and consultation about usage of space instrumentation.

Under contract to the Air Force Research Laboratory, we developed the Atmospheric Radiance Code (ARC) to model conditions for which local thermodynamic equilibrium (LTE) does not prevail. The model incorporates the first line-by-line radiative transfer algorithm for optically thick infrared bands. This model calculates vibrational state populations, cooling rates, and line-of-sight radiance for several molecules - most notably, CO2.

We subsequently participated in the development of the first non-LTE algorithm for retrieving atmospheric temperature throughout the mesosphere. NASA implements this algorithm in operational software used by its ongoing TIMED/SABER program, and ARCON continues to consult on the validation of data products from this mission.

We have conducted science studies based on measurements from SABER, instruments on the Air Force MXS satellite, and other sources. Our most recent publication concerns the remarkable effects of sudden stratospheric warmings of 2004 and 2006 on the observed properties of the hydroxyl layer in the upper mesosphere.