Semidiurnal tides from the extended Canadian Middle Atmosphere Model (CMAM) and comparisons with TIMED Doppler interferometer (TIDI) and meteor radar observations
Semidiurnal tides from the extended Canadian Middle Atmosphere Model (CMAM) and comparisons with TIMED Doppler interferometer (TIDI) and meteor radar observations
复制标题
DOI：
10.1016/j.jastp.2007.07.014
复制
发表时间：
2007-12
影响因子：
1.9
通讯作者：
Jian Du;W. Ward;J. Oberheide;Takuji Nakamura;T. Tsuda
中科院分区：
文献类型：
--
作者：
Jian Du;W. Ward;J. Oberheide;Takuji Nakamura;T. Tsuda
加拿大中层大气模式（英语：Canadian Middle Atmosphere Model）是一个大气环流模式，从地面延伸到210公里。空间复谱分析适用于水平风模拟的扩展CMAM获得半日潮振幅和相位（从e5到w5）在中层和低热层（MLT）地区。在中纬度地区，主要的w2迁移成分和8个非迁移潮汐（w3，w 4，w5，e1，e2，e3，e4和e5）的存在被确定。分量w1和s 0在高纬度趋于最大，将在后面的论文中单独讨论。迁移半日潮（w2）在中纬度地区的纬向风和纬向风的振幅都超过20 ms − 1。它的形式比较以及公布的结果。与迁移半日潮相比，非迁移半日潮的振幅是不可忽略的。w3和e2的振幅分别超过12和8 ms −1。本文用TIMED多普勒干涉仪（TIDI）在85 - 105 km高度和45°S-45°N纬度上测得的风场的四个非移动半日分量（w_3、w_4、e_1和e_2）进行了比较。总的来说，CMAM和TIDI振幅的基本纬度结构一致，年平均振幅之间的一致性因分量而异。相对于TIDI结果，CMAM的季节变化w 4是在良好的协议，e2是在合理的协议，w3是在部分协议和e1是在较差的协议。将模式中的11个半日风分量叠加，生成雅加达（6°S，106°E）和科托塔邦（0°，100°E）的总半日风，并与这些地点的两个赤道流星雷达站的测量结果进行比较。分量对重建振幅的相对贡献随月份而变化。CMAM重建通常比雷达结果大1到2倍。雷达数据中的相位通常相对于高度是固定的，而在CMAM重建中它们通常随着高度而减小。
The extended Canadian Middle Atmosphere Model (extended CMAM) is a general circulation model, which extends from the surface to about 210km. Spatial complex spectral analysis is applied to horizontal winds simulated by the extended CMAM to obtain semidiurnal tidal amplitudes and phases (from e5 to w5) in the mesosphere and lower thermosphere (MLT) region. The dominant w2 migrating component and the presence of eight nonmigrating tides (w3, w4, w5, e1, e2, e3, e4 and e5) in the mid-latitudes are identified. Components w1 and s0, which tend to maximize at high latitudes, will be discussed separately in a later paper. The migrating semidiurnal tide (w2) has amplitudes reaching over 20ms−1for both zonal and meridional winds in the mid-latitude region. Its form compares well to the published results. The amplitudes of nonmigrating semidiurnal tides are non-negligible compared with the migrating semidiurnal tides. The amplitudes for w3 and e2 exceed 12 and 8ms−1, respectively. Comparisons are made with four nonmigrating semidiurnal components (w3, w4, e1 and e2) derived from the TIMED Doppler interferometer (TIDI) wind measurements between 85 and 105km altitude and between 45°S and 45°N latitude. Overall, the basic CMAM and TIDI latitudinal structures of the amplitudes agree well and the agreement between the annual mean amplitudes varies with component. Relative to the TIDI results, the CMAM seasonal variations of w4 are in good agreement, of e2 are in reasonable agreement, of w3 are in partial agreement and of e1 are in poor agreement. The 11 semidiurnal components from the model are superimposed to generate the total semidiurnal winds at Jakarta (6°S, 106°E) and Kototabang (0°, 100°E) and are compared with measurements from two equatorial meteor radar stations at these sites. The relative contributions of components to the reconstructed amplitude vary from month to month. The CMAM reconstructions are generally larger than the radar results by a factor varying between one and two. The phases in the radar data are typically stationary with respect to height, whereas they generally decrease with height in the CMAM reconstruction.