Long‐term MF radar observations of solar tides in the low‐latitude mesosphere: Interannual variability and comparisons with the GSWM
Long‐term MF radar observations of solar tides in the low‐latitude mesosphere: Interannual variability and comparisons with the GSWM
复制标题
DOI：
10.1029/98jd00482
复制
发表时间：
1998-04
影响因子：
--
通讯作者：
R. Vincent;S. Kovalam;D. Fritts;J. Isler
中科院分区：
文献类型：
--
作者：
R. Vincent;S. Kovalam;D. Fritts;J. Isler
在三个赤道和亚热带站点(阿德莱德、圣诞岛和考艾岛)进行了80-100公里高度范围内的长期MF雷达风场测量，以产生气候学和研究太阳潮汐的年际变化。阿德莱德提供了12年的数据，其他站点提供了长达6年的数据，并每30天进行一次分析。气候学数值与全球尺度波动模式(GSWM)进行了比较。对于全日潮汐，实测值和模型幅值和相位之间有很好的一致性，但半日模型值与观测值的一致性较差。日潮汐幅值和潮位相具有较强的季节变异性。振幅在3月达到最大值，副极大值出现在7/8和10月，而阿德莱德和考艾岛的位相表现出年周期，从夏季到冬季，位相提前了∼4-6小时。半日潮的振幅很少超过10m S−1。在阿德莱德和考艾岛，潮位相在春分前后快速移动，但在圣诞岛有更复杂的位相变化。昼夜潮汐表现出很强的年际变异性，特别是在三月分点附近。这与赤道平流层纬向风的准两年振荡(QBO)有关，当平流层风向东时，QBO的幅度大于气候平均值，而当QBO向西时，QBO的幅度小于气候平均值。相比之下，日潮和半日潮的位相几乎没有系统的年际变化。
Long-term MF radar wind measurements in the 80–100 km height range made at three equatorial and subtropical sites (Adelaide, Christmas Island, and Kauai) are used to produce climatologies and to study interannual variability of solar tides. Twelve years of data were available for Adelaide and up to 6 years at the other sites and are analyzed in 30-day intervals. The climatological values are compared with the Global Scale Wave Model (GSWM). Good agreement between the measured and model amplitudes and phases is found for the diurnal tide, but the semidiurnal model values agree less well with the observations. The diurnal tidal amplitudes and phases show strong seasonal variability. Maximum amplitudes are attained in March, and subsidiary maxima are observed in July/August and October, while the phase shows an annual cycle at Adelaide and Kauai, with the phase advancing by ∼4–6 hours from summer to winter. Amplitudes of the semidiurnal tide rarely exceed 10 m s−1. The phases undergo rapid shifts around the equinoxes at Adelaide and Kauai, but there is a more complicated phase variation at Christmas Island. The diurnal tide shows strong interannual variability in amplitude, especially near the March equinox. There appears to be an association with the quasi-biennial oscillation (QBO) in zonal winds in the equatorial stratosphere, with the amplitudes being larger than the climatological average in years when the stratospheric winds are eastward and smaller than average when the QBO is in its westward phase. In contrast, the phase of the diurnal tide, as well as the semidiurnal tide, shows little systematic interannual variability.