During geomagnetic storms, Joule heating is a major heating source of the upper atmosphere that is not well estimated, due to a lack of measurements. This leads to uncertainties in orbital calculations. We present simulations with commonly used physics-based models and empirical models that provide measurements of Joule heating. The results show great discrepancies, pointing to the need for measurements in the Earth's Lower Thermosphere-Ionosphere at altitudes where Joule heating maximizes.

Comparisons of wind measurements using two different techniques (ground-based radar and satellite) in Brazil during 2006 were made in order to point out the advantages of each instrument for studies in the mesosphere and upper thermosphere. (i) For short-period variations, the measurements of the satellite were more advantageous. (ii) The monthly climatology using the radar was more appropriate. (iii) For long periods (longer than a few months), both instruments responded satisfactorily.