CEDAR: Critical Evaluation of the Hydroxyl Radical (OH) Meinel Band Einstein A Coefficients

几十年来，OH分子的Meinel带夜光发射一直被用来表征中间层温度。空气单体目前依赖于排放系数（“A系数”），PI认为需要修订。恢复使用现有的一套A系数的温度相差高达15 K从第一原理计算的实际温度。中间层温度的大的不确定性可能对模拟中间层和低热层（MLT）的化学、输送和环流产生不利影响。这些不确定性也破坏了监测MLT长期温度的努力。 这个建议解决了OH温度的测定，1）使用强度校准的夜光数据，已同时收集了一个大的光谱范围内从天文天空光谱; 2）进行比较，最近获得的OH Meinel带线强度，和最新的第一原理计算的发射系数。这项研究将有助于理解基本的物理量子过程，小尺度和大尺度的大气运动，以及低热层的长期温度变化。

The Meinel band nightglow emission from the OH molecule has been used for decades to characterize mesospheric temperatures. Aeronomers currently rely on emission coefficients ("A coefficients") that the PIs argue are in need of revision. Temperatures recovered using the existing set of A coefficients differ by up to 15 K from actual temperatures computed from first principles. Large uncertainty in the mesospheric temperature can have detrimental effects on modeling chemistry, transport and circulation of the mesosphere and lower thermosphere (MLT). The uncertainties also undermine efforts to monitor the long-term temperatures in the MLT. This proposal addresses the OH temperature determination by 1) using intensity-calibrated nightglow data that has been collected simultaneously over a large spectral range from astronomical sky spectra; 2) making comparisons between such recently obtained OH Meinel band line intensities, and the most recent first principles calculations of the emission coefficients. This research will contribute to understanding fundamental physical quantum processes, atmospheric motions on small and large scales, and long-term temperature change in the lower thermosphere.