Mid-latitude temperatures at 87 km: Results from multi-instrument Fourier analysis

Using a novel Fourier fitting method we com- bine two years of mid-latitude temperature measurements at 87 km from the High Resolution Doppler Imager, the Colorado State University lidar, and the Peach Mountain Interferometer. After accounting for calibration bias, sig- nificant local-time variations on the order of 10 K were ob- served. Stationary planetary waves with amplitudes up to 10 K were observed during winter, with weaker wave ampli- tudes occurring during other seasons. Because of calibration biases among these instruments, we could estimate the an- nual mean temperature to no better than 193.5 4- 8.5 K. (1991) and recent work by Leblanc et ed. (1999). We present a methodology for making statistical estimates of mid-latitude temperature fields using a combination of satel- lite and ground-based data. Results at a height of 87 km are presented here to illustrate the method and its potential future use with larger multi-instrument data sets. Figure la shows the combined longitudinal and tempo- ral sampling pattern of the temperature field between 41 o 4. 1 o N at 87 km over a two-year period from the High Resolution Doppler Interferometer (HRDI) (Ortland et at.