Subauroral polarization streams: observations with the Hokkaido and King Salmon SuperDARN radars and modeling
Subauroral polarization streams: observations with the Hokkaido and King Salmon SuperDARN radars and modeling
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DOI：
10.5194/angeo-26-3317-2008
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发表时间：
2008-10
影响因子：
1.9
通讯作者：
A. Koustov;N. Nishitani;Y. Ebihara;T. Kikuchi;M. Hairston;D. André
中科院分区：
文献类型：
--
作者：
A. Koustov;N. Nishitani;Y. Ebihara;T. Kikuchi;M. Hairston;D. André
新安装的SuperDARN北海道高频雷达监测磁纬45和65之间的电离层等离子体流，因此，与位于阿拉斯加州Salmon国王的另一个SuperDARN雷达以及北极阿拉斯加地区的DMSP卫星和地面仪器相结合，在研究极光下偏振流（SAPS）方面具有很大的潜力。初步调查表明，虽然北海道雷达经常探测到SAPS，但它们的速度相当低，在其最合适的中心波束中为150 m/s。在这项研究中，异常快速的北海道流高达800米/秒的观测。对2007年4月1日的事件进行了详细的调查。结果表明，高速回波出现后，亚暴爆发在北美与30分钟的延迟。在纬度方面，速度峰值外的极光椭圆形，签名的一个分离的偏振射流是偶尔的，并不明显。国王鲑鱼雷达操作同时检测SAPS签名，以及但在不同的时间和地点。综合环流模式对4月1日事件的模拟合理地确定了快速流动发生的时期，但低估了速度。研究的事件表明，亚暴注入的粒子群可能会加强预先存在的SAPS流，并导致预测和观测的不匹配。
The newly installed SuperDARN Hokkaido HF radar monitors ionospheric plasma flow between magnetic latitudes of 45 and 65 and thus has a great potential for studies of subauroral polarization streams (SAPS) in com- bination with another SuperDARN radar located at King Salmon, Alaska as well as the DMSP satellites and ground- based instruments in the Alaskan sector of the Arctic. Pre- liminary survey shows that although SAPS are often detected with the Hokkaido radar, their velocities are rather low, to the order of 150 m/s in its most suitable central beams. In this study, observations of unusually fast Hokkaido flows of up to 800 m/s are presented. The event of 1 April 2007 is inves- tigated in detail. It is shown that high-velocity echoes appear after substorm onsets over North America with a delay of 30 min. In terms of latitude, the velocity peaks just outside the auroral oval; signatures of a detached polarization jet are occasional and not pronounced. The King Salmon radar op- erating concurrently detects SAPS signatures as well but at different times and locations. Simulation with the Compre- hensive Ring Current Model for the 1 April event reasonably identifies the period of fast flow occurrence but the velocity is underestimated. The event studied suggests that substorm- injected particle populations may intensify the pre-existing SAPS flow and lead to a mismatch of the predictions and observations.