Thermospheric temperature and magnetic field measurements from Mt Abu during a geomagnetically disturbed period – a case study

During the recovery phase of a 'moderate' geomagnetic storm, spectroscopically measured night-time thermospheric temperatures from Mt Abu (24.6°N, 73.7°E, dip 19.09°) are found to deviate considerably (∼ 200–600 K) from the MSIS-90 model temperatures on many occasions, implying the model's limitations as applied to low-latitude thermosphere. The measured temperatures exhibit oscillatory features as opposed to the flat, featureless temperature profiles rendered by the MSIS-90 model. The temperature variabilities are found to succeed the variations in the time rate of change of the total magnetic field measured by a standard Proton Precession Magnetometer by ∼ 12.5 h, revealing the 'response time' of the low-latitude thermosphere to the disturbances over higher latitudes.