Aa Ercha, Zhang Shun-Rong, Wang Wenbin, Erickson Philip J, Qian Liying, Eastes Richard, Harding Brian J, Immel Thomas J, Karan Deepak K, Daniell Robert E, Coster Anthea J, Goncharenko Larisa P, Vierinen Juha, Cai Xuguang, Spicher Andres
Haystack Observatory Massachusetts Institute of Technology Westford MA USA.
High Altitude Observatory National Center for Atmospheric Research Boulder CO USA.
J Geophys Res Space Phys. 2022 Jun;127(6):e2022JA030527. doi: 10.1029/2022JA030527. Epub 2022 Jun 3.
Following the 2022 Tonga Volcano eruption, dramatic suppression and deformation of the equatorial ionization anomaly (EIA) crests occurred in the American sector ∼14,000 km away from the epicenter. The EIA crests variations and associated ionosphere-thermosphere disturbances were investigated using Global Navigation Satellite System total electron content data, Global-scale Observations of the Limb and Disk ultraviolet images, Ionospheric Connection Explorer wind data, and ionosonde observations. The main results are as follows: (a) Following the eastward passage of expected eruption-induced atmospheric disturbances, daytime EIA crests, especially the southern one, showed severe suppression of more than 10 TEC Unit and collapsed equatorward over 10° latitudes, forming a single band of enhanced density near the geomagnetic equator around 14-17 UT, (b) Evening EIA crests experienced a drastic deformation around 22 UT, forming a unique X-pattern in a limited longitudinal area between 20 and 40°W. (c) Thermospheric horizontal winds, especially the zonal winds, showed long-lasting quasi-periodic fluctuations between ±200 m/s for 7-8 hr after the passage of volcano-induced Lamb waves. The EIA suppression and X-pattern merging was consistent with a westward equatorial zonal dynamo electric field induced by the strong zonal wind oscillation with a westward reversal.
2022年汤加火山爆发后，在距离震中约14000公里的美洲区域，赤道电离异常（EIA）峰值出现了显著的抑制和变形。利用全球导航卫星系统总电子含量数据、全球尺度的临边和盘面紫外图像观测、电离层连接探测器风数据以及电离层探测仪观测，对EIA峰值变化及相关的电离层-热层扰动进行了研究。主要结果如下：（a）在预期的火山爆发引发的大气扰动向东经过后，白天的EIA峰值，尤其是南部的峰值，显示出超过10个总电子含量单位的严重抑制，并在超过10°纬度的范围内向赤道方向坍塌，在协调世界时14 - 17时左右在地磁赤道附近形成了一条增强密度的单带；（b）傍晚的EIA峰值在协调世界时22时左右经历了剧烈变形，在西经20°至40°之间的有限经度区域内形成了独特的X形图案；（c）热层水平风，尤其是纬向风，在火山引发的兰姆波经过后7 - 8小时内，在±200米/秒之间呈现出持续的准周期波动。EIA的抑制和X形图案的合并与由具有向西反转的强纬向风振荡引起的向西赤道纬向发电机电场一致。
