On the Seeding of Periodic Equatorial Plasma Bubbles by Gravity Waves Associated With Tropical Cyclone: A Case Study
On the Seeding of Periodic Equatorial Plasma Bubbles by Gravity Waves Associated With Tropical Cyclone: A Case Study
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DOI：
10.1029/2020ja028003
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发表时间：
2020-10
期刊：
影响因子：
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通讯作者：
K. Ajith;Guozhu Li;S. Tulasi Ram;M. Yamamoto;K. Hozumi;P. Abadi;Haiyong Xie
中科院分区：
文献类型：
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作者：
K. Ajith;Guozhu Li;S. Tulasi Ram;M. Yamamoto;K. Hozumi;P. Abadi;Haiyong Xie
了解赤道等离子体泡（EPB）不规则性的日常变化性几十年来一直是一个重大挑战，这使得EPB的确定性预测仍然难以捉摸。在本研究中，我们报告了2013年4月8日和9日在印度尼西亚Kototabang的47 MHz赤道大气雷达观测到的强烈和周期性EPB的情况。周期性的EPB在日落前开始，间隔约200-250公里。根据热带气旋维多利亚引起的深对流激发的重力波，讨论了这些周期性的EPB在日落前的发生和发展。印度气象卫星Kalpana-1上的甚高分辨率辐射计（VHRR）的输出长波辐射测量显示这些天发生了深对流活动。对流层和平流层的GPS无线电掩星（GPS-RO）观测证实了与TC维多利亚相关的深对流区向上传播的GW的存在。还通过磁赤道上空的电离层探测仪观测到了电离层高度的GW特征，并通过磁赤道和气旋中心附近的GPS-TEC（总电子含量）数据观测到了中等尺度（~300 km）GW。从GPS‐TEC和GPS‐RO观测到的GW参数来看，我们推测与TC维多利亚相关的主要GW耗散产生的次级GW可能在这连续两天期间作为产生周期性EPB的播种源。
Understanding the day‐to‐day variability of equatorial plasma bubble (EPB) irregularities has been a major challenge for many decades that makes the deterministic prediction of EPBs remain elusive. In the present study, we report a case of intense and periodic EPBs observed during 8 and 9 April 2013 by the 47‐MHz Equatorial Atmosphere Radar at Kototabang, Indonesia. The periodic EPBs separated by about 200–250 km were initiated before sunset. The presunset onset and development of these periodic EPBs were discussed in light of the gravity waves (GWs) excited in connection with the deep convection due to the tropical cyclone (TC) Victoria. The outgoing long‐wave radiation measurement by very high‐resolution radiometer (VHRR) onboard Indian meteorological satellite Kalpana‐1 shows the occurrence of deep convective activity during these days. The presence of upward propagating GWs from the deep convective region associated with TC Victoria was confirmed using the GPS radio occultation (GPS‐RO) observations in the troposphere and stratosphere. The GW signatures at ionospheric altitudes were also observed from the Ionosonde observations over magnetic equator, and medium‐scale (~300 km) GWs were observed from the GPS‐TEC (Total Electron Content) data near to the magnetic equator and cyclone center. From the GW parameters observed from GPS‐TEC and GPS‐RO, we surmise that the secondary GWs generated by the dissipation of primary GWs associated with TC Victoria could have served as a seeding source on the generation of periodic EPBs during these two consecutive days.