An Empirical Model for the Peak Altitude of the OH Nightglow Emission

Using a multiple linear regression analysis for nearly six years of WINDII records, an empirical formula is determined to calculate the peak altitude of OH nightglow emission. More than 65,000 altitude profiles of volume emission rate collected by WINDII over various latitudes and longitudes during November 1991 to August 1997 are used. The peak altitudes of these profiles increase with decreasing integrated emission rates, showing an inverse relationship. Thus the peak altitude of the OH emission layer is almost completely determined by its integrated emission rate. However, the fitting is improved when a solar cycle dependence is included. A slight improvement results from incorporating an annual component for data over the mid-latitude region. The local time variation makes an insignificant change in the peak altitude of OH nightglow emission, and its effect is not considered. The peak emission altitude is linearly related to the integrated emission rate, the solar F10.7 cm flux, and the sinusoidal annual variation in the model for the OH nightglow. Accordingly, more than 80% of the calculated peak altitudes lies within a 1 km difference of the measured values. By applying this model, ground-based observers will be able to predict the OH emission peak altitude to this accuracy with a confidence level of 80%.