Imaging of Polar Mesosphere Summer Echoes with the 450 MHz Poker Flat Advanced Modular Incoherent Scatter Radar
Imaging of Polar Mesosphere Summer Echoes with the 450 MHz Poker Flat Advanced Modular Incoherent Scatter Radar
复制标题
使用 450 MHz Poker Flat 高级模块化非相干散射雷达对极地中间层夏季回波进行成像
DOI：
10.1029/2007gl031476
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发表时间：
2007
影响因子：
5.2
通讯作者：
J. Kelly
中科院分区：
文献类型：
--
作者：
M. Nicolls;C. Heinselman;E. A. Hope;S. Ranjan;M. Kelley;J. Kelly
极地中层夏季回波(PMSE)发生在极地夏季月份的中层顶附近。PMSE主要是在甚高频下研究的，但在更高的频率上也有一些检测到。在这里，我们报告了使用450 MHz(67厘米)扑克平板高级模块化非相干散射雷达(PFISR)首次检测到PMSE。观测到回波的体积反射率(单位体积的雷达散射截面)接近2-3×10−17 m−1。2007年6月11日，该系统以26波束定位模式运行，在85公里高度、仰角低至∼50°的约80×80平方公里区域内观察方向。测量显示，除了更小、更局部化的结构外，从北方漂移来的片状(数十公里)不规则区域。没有证据表明这些UHF回波具有很强的方位敏感性，因为PMSE在所有方向上都观察到了相对均匀的强度。观测表明，存在随背景风场漂移的不规则化石，以及可能与活跃的中性空气湍流有关的发展中的不规则区域。
Polar Mesosphere Summer Echoes (PMSE) occur near the mesopause during the polar summer months. PMSE are primarily studied at VHF, however there have been some detections at higher frequencies. Here, we report on some of the first detections of PMSE with the 450 MHz (67 cm) Poker Flat Advanced Modular Incoherent Scatter Radar (PFISR). Echoes were observed with volume reflectivities (radar scattering cross section per unit volume) near 2–3 × 10−17 m−1. On 11 June 2007, PFISR was operating in a 26‐beam position mode, with look directions spread over an approximately 80 by 80 km2 region at 85 km altitude with elevation angles as low as ∼50°. The measurements showed patchy (tens of kilometer) irregularity regions drifting in from the north, in addition to smaller, more localized structures. There was no evidence for strong aspect sensitivity of these UHF echoes, as PMSE was observed in all look directions with relatively uniform intensity. The observations indicate the presence of fossilized irregularities drifting with the background wind field as well as areas of developing irregularities possibly associated with the presence of active neutral air turbulence.