Thermospheric Traveling Atmospheric Disturbances in Austral Winter From GOCE and CHAMP

Abstract

AbstractIn this study, we analyze the thermospheric density data provided by the Gravity Field and Steady‐State Ocean Circulation Explorer during June–August 2010–2013 at ∼260 km altitude and the Challenging Minisatellite Payload during June–August 2004–2007 at ∼370 km altitude to study high latitude traveling atmospheric disturbances (TADs) in austral winter. We extract the TADs along the satellite tracks from the density for varying Kp, and linearly extrapolate the TAD distribution to Kp = 0; we call these the geomagnetic “quiet time” results here. We find that the quiet time spatial distribution of TADs depends on the spatial scale (along‐track horizontal wavelength ) and altitude. At z ∼ 260 km, TADs with ≤ 330 km are seen mainly around and slightly downstream of the Southern Andes‐Antarctic region, while TADs with > 800 km are distributed fairly evenly around the geographic South pole at latitudes ≥60°S. At z ∼ 370 km, TADs with ≤ 330 km are relatively weak and are distributed fairly evenly over Antarctica, while TADs with > 330 km make up a bipolar distribution. For the latter, the larger size lobe is centered at ∼60°S, and is located around, downstream and somewhat upstream of the Andes/Antarctic Peninsula, while the smaller lobe is located over the Antarctic continent at 90°–150°E. We also find that the TAD morphology for Kp ≥ 2 and > 330 km depends strongly on geomagnetic activity, likely due to auroral activity, with greatly enhanced TAD amplitudes with increasing Kp.