基于MST雷达数据的中纬对流层和低平流层大气行星波研究

通过分析中国河北香河站MST (Mesosphere-Stratosphere-Troposphere)雷达 2012-2014年的水平风场数据, 研究了北半球中纬地区对流层和低平流层 (Troposphere and Lower Stratosphere, TLS)区域大气行星波的特性. 谱分 析发现, 在这一区域准16天波和准10天波占据主导地位, 准16天波更为显著. 在 对流层区域, 行星波具有丰富的频谱成分, 活动具有间断性, 持续时间一般不 超过三个月, 并没有明显的季节性变化特征, 其中纬向分量的振幅大于经向分量. 在 平流层区域(高度17km以上), 行星波一般出现在冬季, 并且主要在纬向分量中. 通常平流层区域的振幅要小于对流层区域. 结合MERRA再分析资料分 析了强行星波传播特性, 结果表明: 2014年2-3月纬向分量中的准16天波垂 直向上传播, 垂直波长约为64km, 纬圈波数约为2, 纬向传播方向自西向东, 水平波长约为15324.7km, 对应的相速度为11.1m·s-1 (向东为正); 2014年5月纬向分量中的准10天波在10~18km高度范围内向下传播, 垂直波长约为50km, 纬圈波数约为1, 传播方向自西向东, 水平波长约为 30649.4km, 对应相速为35.5m·s-1. 

Mid-latitude Planetary Waves Observation from MST Radar Measurements in the Troposphere and Lower Stratosphere

Characteristics of the Planetary Waves (PW) in the Troposphere and Lower Stratosphere (TLS) were investigated with Mesosphere-Stratosphere-Troposphere (MST) radar wind measurements in Xianghe (116.9°E, 39.8°N) from January 2012 to December 2014. Spectral analyses show that the TLS region is dominated by quasi-16-day and quasi-10-day PW, while the former ones are more significant. In the troposphere regions (above 17km height), the PW with dynamic periods are primarily observed, which last less than three months and don't indicate significant seasonal variation. Meanwhile, the amplitudes of the PW in the zonal direction exceed those in the meridional direction. In the lower stratosphere regions, intense PW mainly occur in the zonal component in winter. The amplitudes in the stratosphere are generally smaller than those in the troposphere. This paper also discusses the propagation characteristics of PW based on MST radar data and MERRA reanalysis data. The result shows that zonal component of the quasi-16-day PW observed in February and March 2014 propagated eastward with a zonal wave number of 2 (the horizontal wave length was about 15324.7km). The corresponding phase velocity was 11.1m·s-1 (positive eastward). The quasi-16-day PW propagated upward vertically with a 64km vertical wave length. In addition, the observation in May 2014 showed that the quasi-10-day PW in the zonal component propagated eastward with a zonal wave number of 1. Its horizontal wave length, phase velocity and vertical wave length were 30649.4km, 35.5m·s-1 and 50km respectively.