The goal of this research is to close these information gaps. The researchers will adapt their laboratory hardware to measure the fractional yields of vibrationally excited OH in the range of 150-300 K. This information is needed to accurately recover temperatures from satellite and ground-based observations of OH airglow. Knowledge of mesopause temperature is particularly important for quantifying the heat budget of this atmospheric region, and for monitoring long-term trends.
At altitudes around 87 km, the exothermic H + O3 reaction produces vibrationally excited hydroxyl (OHv). This molecule radiates visible and near infrared light ("airglow") from which it is possible infer atmospheric density, temperature, and species concentrations. The OHv molecule is therefore an extremely valuable observable in the mesopause. Although the total reaction rate coefficient of H + O3 is well known, estimates of the vibrational OH product yields vary considerably. Moreover, the temperature dependence of these yields has never been determined for conditions relevant to the mesosphere.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
