Estimation of scaling factors of thermospheric density provided by empirical models using SLR observations to Low Earth Orbiting satellites

The neutral density of the thermosphere is one of the key parameters used, in particular, to compute atmospheric drag acting on the Earth’s orbiting satellites and objects at an altitude below 1000 km. Various empirical and physical models of the thermospheric density have been derived since 1961. The most widely used empirical models are CIRA86, NRLMSISE00, JB2008, and DTM2013. A new empirical model (CHTherm-2018) has been recently developed at GFZ using 9-year accelerometer measurements from the CHAMP satellite from August 2000 to July 2009 when it flew at an altitude range from 460 to 310 km. A new method for estimating scale factors of integrated thermospheric density has been developed at DGFI-TUM using Satellite Laser Ranging (SLR) observations to spherical Earth orbiting satellites, in combination with a full precise orbit determination of these satellites. In this method, the total drag coefficient is computed using the Sentman model by averaging over all thermospheric species. Using this approach, we have estimated scale factors of the thermospheric density provided by CIRA86, NRLMSISE00, JB2008, DTM2013 and CH-Therm-2018 using SLR observations to the ANDE-P satellite from 16 August 2009 to 3 October 2009, the ANDE-C satellite from 16 August 2009 to 26 March 2010 and SpinSat from 29 December 2014 to 21 June 2015, i.e. at the periods of low and high solar activity, and the altitude range from 248 to 425 km. In this presentation, we describe the methods and models used and discuss the scaled factors obtained for various models of thermospheric density.     «

The neutral density of the thermosphere is one of the key parameters used, in particular, to compute atmospheric drag acting on the Earth’s orbiting satellites and objects at an altitude below 1000 km. Various empirical and physical models of the thermospheric density have been derived since 1961. The most widely used empirical models are CIRA86, NRLMSISE00, JB2008, and DTM2013. A new empirical model (CHTherm-2018) has been recently developed at GFZ using 9-year accelerometer measurements from t...     »