Morphology of OH Meinel Band Emissions Observed by SABER/TIMED: Implication for Comparison and Interpretation of groundbased OH Airglow Observations

Abstract:

The OH Meinel band emissions of various vibrational manifolds have been observed for many decades by groundbased optical instruments to study the changes of atmospheric properties near the mesopause region. These include the temporal and spatial variablities of atmospheric temperature and composition at the emission region near 87 km and processes responsible for the observed changes. Much of our previous and current knowledge of dynamical processes (i.e. tides and waves), thermal properties (i.e. inter-annual cycles), and decadal-scale changes (i.e. solar cycle and human-induced) in the mesosphere have been gained from these important observations. Groundbased measurements, however, are constrained to limited locations, cloud-free and dark nights (local time) with very poor vertical resolution. The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the TIMED satellite has provided nearly 14 years of continuous observations of OH (5-3, 4-2) 1.6 μm and OH (9-7, 8-6) 2.0 μm Meinel band emissions. Most importantly, it has provided over one solar cycle long of well temporally and spatially sampled OH emissions with excellent vertical resolution. In this paper, we will present the morphological properties of the OH emissions at 1.6 μm and 2.0 μm observed by SABER and discuss the implication for satellite/ground measurement comparisons and the interpretation of past and future groundbased OH observations.