Long-term variability in the equatorial middle atmosphere zonal wind
Long-term variability in the equatorial middle atmosphere zonal wind
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DOI：
10.1029/96jd00575
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发表时间：
1996-05
影响因子：
--
通讯作者：
M. Burrage;R. Vincent;H. G. Mayr;W. Skinner;N. Arnold;P. Hays
中科院分区：
文献类型：
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作者：
M. Burrage;R. Vincent;H. G. Mayr;W. Skinner;N. Arnold;P. Hays
自 1991 年 11 月以来，高层大气研究卫星 (UARS) 上的高分辨率多普勒成像仪 (HRDI) 提供了平流层、中间层和低热层水平风场的测量。该数据集跨越了 3 年多的时间，促进了对几乎全球背景环流的长期行为的研究。中高纬度地区纬向环流的特点是年振荡。在低纬度地区（±30°），平流层上方最显着的长期变化是中间层半年振荡（MSAO），它在赤道附近海拔 80 至 85 公里处达到最大值。对时间序列的进一步分析揭示了额外的强烈变化，幅度接近 30 ms−1，周期约为 2 年。该特征显示出与MSAO相同的高度和纬度结构，并与平流层准两年期振荡（QBO）表现出相位关系。圣诞岛中频雷达（北纬 2°，西经 130°）的观测证实了该中层 QBO (MQBO) 的存在。这些观察结果支持了一项建模研究的最新发现，该模型研究通过小尺度重力波所穿过的底层风的选择性过滤来生成 MQBO。
The high resolution Doppler imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) has provided measurements of the horizontal wind field in the stratosphere, mesosphere, and lower thermosphere since November 1991. This data set, which spans a period of more than 3 years, has facilitated an investigation of the long-term behavior of the background circulation on a nearly global basis. At middle and high latitudes the zonal circulation is characterized by an annual oscillation. At low latitudes (±30°) the most prominent long-term variation above the stratopause is the mesosphere semiannual oscillation (MSAO), which maximizes near the equator at an altitude of between 80 and 85 km. Further analysis of the time series reveals an additional strong variation, with an amplitude near 30 ms−1 and a period of about 2 years. This feature shows the same altitude and latitude structure as the MSAO and exhibits a phase relationship with the stratospheric quasi-biennial oscillation (QBO). Observations from the Christmas Island MF radar (2°N, 130°W) confirm the presence of this mesospheric QBO (MQBO). These observations support recent findings from a modeling study which generates an MQBO via the selective filtering of small-scale gravity waves by the underlying winds they traverse.