April 26, 12:00 pm - 1:00 pm
April 26, 12:00 pm - 1:00 pm
Approximating the Stormtime Dst Index and Thermospheric Using DMSP Magnetometer Measurements
Bill Burke (Air Force Research Lab)
This study explores the feasibility of performing operational estimates of the prompt Dst index using variations in the horizontal component (DBH) of the Earth’s magnetic vector detected by DMSP spacecraft while crossing the magnetic equator. Measurements are first compared with predictions of the 2005 International Geomagnetic Reference Field (IGRF) model. Quiet-time offset baselines are then established as functions of longitude for the years 2005 to 2009. Year-to-year progression of these baselines reflects secular variations of the main field. Thus, quiet-time baseline calculations for each spacecraft must be updated at regular intervals. Running-averaged values of DBH, inferred from magnetometers on DMSP F16 and F17 follow provisional Dst traces during active intervals of the 2005 to 2009 test interval. Except during the maximum epochs of magnetic of storms, exospheric temperature increases estimated from DBH variations are in reasonable agreement with those inferred from GRACE accelerometer data. The existence of a solar-cycle dependence for energy coupling to the solar wind is demonstrated.