基于三亚VHF雷达的场向不规则体观测研究:3.距离扩展流星尾迹回波

【作者】 李明； 李国主； 宁百齐； 胡连欢；

【机构】 北京空间环境国家野外科学观测研究站中国科学院地质与地球物理研究所； 中国科学院研究生院；

【摘要】 距离扩展流星尾迹回波(RSTE,range spread trail echo)观测通常采用高功率大孔径雷达。本文利用三亚(18.4°N,109.6°E)VHF雷达观测,分析研究了小功率VHF雷达观测的RSTE特征。结果表明,三亚VHF雷达在相干散射模式观测的RSTE,其发生和演化的主要形态特征类似高功率大孔径雷达的观测结果。通过2011年8月期间,三亚VHF雷达相干散射模式观测的RSTE,与同时的全天空流星模式观测的镜面流星尾迹(SE,specular trail echo)数据,统计分析了RSTE和SE随地方时以及高度的变化,发现短持续时间RSTE与SE具有类似的时间-高度变化特征,而长持续时间RSTE发生的峰值时间,相比SE和短持续时间RSTE向晨侧偏移,且长持续时间RSTE对高度的依赖性比短持续时间RSTE显著。此外,全天空流星模式观测SE的数量远多于相干散射模式观测的RSTE数量,可能与不同模式下的观测角度、波束宽度等因素相关。更多还原

【Abstract】 Observations on range spread trail echoes(RSTEs) have been generally limited to high power large aperture radars.In this study,we use trail echoes observed with the Sanya(18.4°N,109.6°E) VHF radar to investigate the occurrence characteristics of RSTEs.The observational results show that the generation and evolution of RSTEs detected by the low power coherent radar are similar to the RSTEs measurements made with high power radars.The time-height distributions of RSTEs and specular meteor trail echoes(SEs),respectively observed by the coherent scattering and the all-sky meteor detection modes of the Sanya VHF radar during August 2011,are also investigated.For short-lived RSTEs,the mean time-height distributions are consistent with those of SEs.However,SEs and long-duration RSTEs show significant differences in the peak occurrence time and height dependence.It is found that the long-duration RSTEs occur earlier in the dawn side and show a clearer dependence on altitude.Furthermore,the number of SEs is greater than that of RSTEs,which could be associated with the radar beam width and viewing geometry.更多还原