The diurnal, latitude, solar flux, and geomagnetic activity variations
in thermospheric NO density measured at latitudes as high as 70-degre
es have been parameterized with a simple, empirical model. Consistent
trends are found in both rocket and satellite measurements, although t
here are some differences that suggest the presence of systematic erro
rs that add factor of 2 uncertainties to the model predictions. While
NO measurements taken with IR emission and gamma band fluorescence tec
hniques are in reasonable agreement, evidence suggests that the ion co
mposition and continuum chemiluminescence methods may be less accurate
. The current model provides a convenient means for estimating daytime
and nighttime NO densities for use in atmospheric chemistry and radia
tion studies.