Thermospheric Traveling Atmospheric Disturbances in Austral Winter From GOCE and CHAMP

In 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 λtrack ) and altitude. At z ∼ 260 km, TADs with λtrack ≤ 330 km are seen mainly around and slightly downstream of the Southern Andes‐Antarctic region, while TADs with λtrack > 800 km are distributed fairly evenly around the geographic South pole at latitudes ≥60°S. At z ∼ 370 km, TADs with λtrack ≤ 330 km are relatively weak and are distributed fairly evenly over Antarctica, while TADs with λtrack > 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 λtrack > 330 km depends strongly on geomagnetic activity, likely due to auroral activity, with greatly enhanced TAD amplitudes with increasing Kp.

在这项研究中，我们分析了重力场与稳态海洋环流探测卫星在2010 - 2013年6 - 8月期间于约260千米高度提供的热层密度数据，以及挑战小卫星有效载荷在2004 - 2007年6 - 8月期间于约370千米高度提供的数据，以研究南半球冬季高纬度行进性大气扰动（TADs）。我们从不同Kp值下的密度数据中沿卫星轨道提取TADs，并将TAD分布线性外推到Kp = 0；在此我们将这些结果称为地磁“平静时间”结果。我们发现，TADs的平静时间空间分布取决于空间尺度（沿轨道水平波长λ轨道）和高度。在z约为260千米处，λ轨道≤330千米的TADs主要出现在南安第斯 - 南极地区周围及稍下游区域，而λ轨道>800千米的TADs在纬度≥60°S的地理南极周围相当均匀地分布。在z约为370千米处，λ轨道≤330千米的TADs相对较弱，在南极洲上空相当均匀地分布，而λ轨道>330千米的TADs呈双极分布。对于后者，较大的瓣以约60°S为中心，位于安第斯山脉/南极半岛周围、下游以及稍上游区域，而较小的瓣位于东经90° - 150°的南极大陆上空。我们还发现，对于Kp≥2且λ轨道>330千米的TAD形态强烈依赖于地磁活动，可能是由于极光活动，随着Kp值的增加，TAD振幅大幅增强。