The observed and modeled low to mid latitude thermospheric response to solar wind forcing from 2001 to 2006

Total thermospheric density retrieved from the STAR accelerometer measurements made onboard CHAMP since may 2001 is used to define a disturbance coefficient that characterize at low and mid latitudes the global thermospheric perturbation associated to Solar wind forcing. No projection of satellite data at a given altitude is performed, meaning that the disturbance coefficients do not depend on a priori hypothesis on the atmospheric scale height. The statistical behavior of the disturbance coefficient is presented for high and for low solar activity conditions, and compared with several semi-empirical models. The observed and modeled behavior of the thermosphere during typical storms is also shown. Our results are used to discuss the description of magnetic activity within the codes, and the possible use of new geomagnetic indices with different time or spatial resolution