Ground Magnetic Manifestations of Atmosphere-Ionosphere Coupling by Planetary Waves

Understanding the relation between tides, planetary waves and geomagnetic solar quiet (Sq) variations is an important aspect of atmosphere-ionosphere coupling, and much remains to be learned. In this paper we quantify the contribution of the planetary waves (PW) at 6.5-, 10- and 16-day periods on the variability of ground magnetic perturbations. Solar quiet days with Kp index <3 are examined from six different stations at low and middle latitudes in two different longitudinal sectors [(IAGA code, geographic latitude, geomagnetic latitude, geographic longitude),(IRT 52.27°, 42.20°, 104.45°), (LZH,36.1°, 26.14°,103.84°),(PHU,21.03°,11.05°,105.95°),(FRD,38.30°, 48.14°,-52.73°),( SJG, 18.11°, 28.04°, -66.15°),( KOU, 5.21°, 14.61°, -77.37°)] during Sept 2008-Sept 2010.The ground-based geomagnetic perturbations are compared with co-located TIMED/TIDI measurements of PW wind amplitudes at the same periods near 110 km. The wind and magnetic field PW amplitudes are not highly correlated at each station, and reasons for that are discussed. The contributions of these PW to the total variability of the magnetic perturbations will be reported.